Aspiration catheter systems

Abstract

Coaxial catheter system (150), wherein the system comprises: a catheter (200), comprising: a distal catheter section (222) with a lumen (223) and a distal end with an opening from the lumen, wherein the lumen (223) has an inner diameter at the distal end of at least about 1.3 mm (0.052 in); and a proximal extension connected to and extending proximal to the distal catheter segment (222), wherein the proximal extension is less flexible than the distal catheter segment; and a catheter delivery element (300), comprising: a tubular section with an inner diameter of at least about 0.35 mm (0.014 in) up to about 0.6 mm (0.024 in), an outer diameter, wherein the outer diameter has at least one abutment point; wherein the difference between the inner diameter of the distal catheter section (222) and the outer diameter of the tubular section at this abutment point is not more than about 0.25 mm (0.010 in); a proximal extension that is connected to and extends proximal to the tubular section, wherein the proximal extension is less flexible than the tubular section; and a tip section which is arranged distal to the at least one end point of the tubular section, wherein the tip section has a length and tapers along at least a section of the length of the tip section, wherein the coaxial catheter system (150) has a delivery configuration characterized by: a) the catheter delivery element (300) which is positioned coaxially within the lumen (223) of the distal catheter section (222), wherein the at least one contact point of the tubular section is substantially aligned with the distal end of the distal catheter section (222), and b) wherein the tip section in the feed configuration has at least three points spaced apart along the length of the tip section, comprising at least three points: a distal point (P1) of at least three points, which is located at a distance proximal to the distal end of the catheter delivery element (300), wherein the distal point (P1) has a first bending force which is not greater than about 0.05 Newton; an intermediate point (P2) of at least three points, which is arranged at a distance proximal to the distal point (P1), wherein the intermediate point (P2) has a second bending force; and a proximal point (P3) of the at least three points, which is arranged at a distance proximal to the intermediate point (P2), wherein the proximal point (P3) has a third bending force; and c) wherein the coaxial system has at least two system points along a length of the coaxial system, the at least two system points comprising: a first system point (S1) of the at least two system points, which is arranged proximal to the distal end of the catheter section (222), wherein the first system point (S1) has a first system bending stiffness; and a second system point (S2) of the at least two system points, which is arranged distal to the first system point (S1) at a distance that is at least approximately 1 mm distal to the distal end of the catheter section (222), wherein the second system point (S2) may be the same as or different from the proximal point (P3), wherein the second system point (S2) has a second system bending stiffness, wherein the bending force of the coaxial catheter system (150) has a generally constant slope over its length, wherein the generally constant slope of the increasing bending force for the distal tip section of the catheter delivery element (300) transitions into a generally constant slope of the increasing bending force for the coaxial catheter system (150), such that there is no significant increase or change in slope between the two.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] The present application claims priority over the concurrently pending provisional US patent application with serial number 62 / 673,009, filed on May 17, 2018. The disclosure of the provisional application is hereby incorporated in its entirety by reference. AREA

[0002] The technology presented here generally relates to medical devices and, in particular, to aspiration catheter systems. GENERAL STATE OF THE ART

[0003] An acute ischemic stroke (AIS) typically occurs when an artery supplying the brain becomes blocked, preventing the delivery of fresh, oxygen-rich blood from the heart and lungs to the brain. These blockages are typically caused by a thrombus or embolus that lodges in the artery and blocks the artery that supplies an area of ​​brain tissue. When an artery is blocked, ischemic damage occurs, and brain cells can cease to function. Furthermore, if the artery remains blocked for more than a few minutes, brain cells can die, potentially leading to permanent neurological deficits or death. Therefore, immediate treatment is critical.

[0004] Two main therapies are used to treat ischemic stroke: thrombolytic therapy and endovascular treatment. The most common treatment to restore flow or reperfusion to the stroke area is intravenous (IV) thrombolytic therapy. Thrombolytic therapy must be initiated within 3 hours of symptom onset for intravenous infusion (4.5 hours in selected patients) or within 6 hours for site-specific intra-arterial infusion. Initiating therapy later has no proven benefit and may put the patient at higher risk of bleeding due to the thrombolytic effect. Endovascular treatment typically involves the use of a set of instruments to mechanically remove the embolus, with or without thrombolytic therapy.

[0005] The spectrum of endovascular treatments includes mechanical embolectomy, which utilizes a retrievable structure, such as a retrievable coil stent (also known as a stent retriever or STENTRIEVER), a wire mesh stent, or a laser-cut stent with supports that can be opened within a clot in the brain anatomy. This allows the clot to be interposed through the supports, creating a channel within the emboli to restore blood flow. The retrievable structure is then retrieved by pulling it out of the anatomy, along with aspiration techniques. Other endovascular techniques for the mechanical removal of AIS-associated emboli include manual aspiration thrombectomy (MAT) (also known as the ADAPT technique).ADAPT / MAT is an endovascular procedure in which large-diameter catheters are inserted through the transfemoral artery and maneuvered through complex anatomy to the level of the embolus, which may be located in the extracranial carotid arteries, vertebral arteries, or intracranial arteries. Aspiration techniques can be used to remove the embolus through the large-diameter catheters. Another endovascular procedure is stentrier-mediated manual aspiration thrombectomy (SMAT) (similar to the stentrier-assisted Solumbra technique). In SMAT, as in MAT, access to the embolus is gained via the transfemoral artery. However, once access is achieved, a retrievable structure is used to retract the embolus into a large-diameter catheter.

[0006] To access the brain's anatomy, guide catheters or guide sheaths are used to advance interventional devices from an arterial access site, typically the femoral artery, to the target. The guide length is determined by the distance between the access site and the desired position of the guide's distal tip. Interventional devices, such as guidewires, microcatheters, and intermediate catheters used for subselective guiding and aspiration, are inserted through the guide and advanced to the target site. Often, the devices are used coaxially; that is, a guidewire within a microcatheter within an intermediate catheter is advanced stepwise to the target site as an array, with the inner, least traumatic elements advanced distally first and the outer elements deployed as supports during advancement.The length of each element of the coaxial assembly takes into account the length of the guide, the length of the proximal connectors on the catheters, and the length required to extend from the distal end.

[0007] Typical three-axis systems, such as those used for aspiration or the delivery of stent retrievers and other interventional devices, require overlapping rows of catheters, each equipped with its own rotary hemostatic valve (RHV) at the proximal end. For example, a guidewire can be advanced through a Penumbra Velocity microcatheter with a first proximal RHV, which can be advanced through a Penumbra ACE68 with a second proximal RHV, which can be advanced through a Penumbra NeuronMAX 088 access catheter with a third proximal RHV positioned in the high carotid artery via a femoral introducer catheter. Maintaining coaxial relationships between these catheters can be technically demanding. The three RHVs must be constantly adjusted with two hands or, more commonly, with four hands (i.e., two operators).Furthermore, the working area of ​​typical three-axis systems for aspiration and / or intracranial device delivery may require a working area of ​​3 to 5 feet at the base of the operating table.

[0008] The time required to access the site of occlusion and restore blood flow to the vessel, even partially, is critical to the success of such interventions. Similarly, the occurrence of distal emboli during the procedure, potentially adverse neurological effects, and complications such as perforations and intracerebral hemorrhages limit the success of the intervention. There is a need for a system of devices and procedures that enable rapid access, optimized catheter aspiration, and treatment to fully restore flow to the blocked cerebral vessel. SUMMARY

[0009] In one described aspect, a coaxial catheter system is described, comprising a catheter and a catheter delivery element. The catheter includes a distal catheter segment with a lumen and a distal end with an opening from the lumen, the lumen having an inner diameter of at least approximately 0.052 inches at the distal end; and a proximal extension connected to and extending proximal to the distal catheter segment, the proximal extension being located below the distal catheter segment. The catheter delivery element includes a tubular segment having an inner diameter of at least approximately 0.014 inches up to approximately 0.024 inches and an outer diameter with at least one abutment point. The difference between the inner diameter of the distal segment and the outer diameter of the tubular segment at this abutment point is not more than approximately 0.010 inches.The catheter delivery element includes a proximal extension connected to and extending proximal to the tubular section, the proximal extension being less flexible than the tubular section; and a tip section located distal to the at least one contact point of the tubular section. The tip section has a length of and tapers along at least a portion of its length. The coaxial catheter system has a delivery configuration characterized in that the catheter delivery element is positioned coaxially within the lumen of the distal catheter section, and the at least one contact point of the tubular section is substantially aligned with the distal end of the distal catheter section.The delivery configuration is further characterized in that the tip section in the delivery configuration has at least three points spaced apart along its length. These at least three points comprise a distal point located proximal to the most distal end of the catheter delivery element, exhibiting a first bending force not greater than approximately 0.05 Newtons; an intermediate point located proximal to the distal point, exhibiting a second bending force; and a proximal point located proximal to the intermediate point, exhibiting a third bending force.The delivery configuration is further characterized in that the coaxial system has at least two system points along a length of the coaxial system. The at least two system points comprise a first system point, which is located proximal to the distal end of the catheter segment and has a first system bending force; and a second system point, which is located distal to the first system point at a distance of at least approximately 1 mm distal to the distal end of the catheter segment and which may be identical to or different from the proximal point and has a second system bending force.

[0010] The difference between the second bending force and the first bending force, divided by the distance between the distal point and the intermediate point, can correspond to a first flexibility slope. The difference between the third bending force and the second bending force, divided by the distance between the intermediate point and the proximal point, can correspond to a second flexibility slope. The average of the first and second flexibility slopes can define an average flexibility slope of the tip section. The difference between the first system bending force and the second system bending force, divided by the distance between the first and second system points, can correspond to a third flexibility slope. The ratio of the third flexibility slope to the average flexibility slope of the tip section can be less than approximately 25.

[0011] The proximal extension of the catheter delivery element may have at least one stiffness point located within approximately 125 cm of the distal end of the catheter delivery element, wherein the at least one stiffness point exhibits a bending force. The ratio of the bending force of the at least one stiffness point to the first bending force of the distal point may be at least approximately 100. Alternatively, the proximal extension of the catheter delivery element may have at least one stiffness point located within approximately 125 cm of the distal end of the catheter delivery element, wherein the at least one stiffness point exhibits a bending force, and the ratio of the bending force of the at least one stiffness point to the first bending force of the distal point may be at least approximately 200.The proximal extension of the catheter delivery element may have at least one stiffness point located within approximately 125 cm of the distal end of the catheter delivery element, wherein the at least one stiffness point exhibits a bending force. The ratio of the bending force of the at least one stiffness point to the first bending force of the distal point may be greater than at least approximately 300. The length of the tip section may be at least approximately 1 cm up to approximately 4 cm. The ratio of the third bending force of the proximal point to the first bending force of the distal point may be at least 2. The ratio of the first system bending force to the first bending force of the distal point may be at least 2. The distal section may have a catheter point located at least 5 mm proximal to the distal end, wherein the catheter point exhibits a catheter bending force.The first bending force at the distal point can be approximately 5% to 15% of the catheter bending force. The third bending force at the proximal point can be approximately 50% to 90% of the catheter bending force. The difference between the first bending force at the distal point and the third bending force at the proximal point can be a function of the wall thickness. The inner diameter at the distal end of the distal catheter segment can be approximately 0.054 inches, and the difference at the flexion point can be approximately 0.006 inches to approximately 0.008 inches. The inner diameter at the distal end of the distal catheter segment can be approximately 0.070 inches to approximately 0.088 inches, and the difference at the flexion point cannot exceed approximately 0.006 inches to approximately 0.008 inches.

[0012] The tubular section of the catheter delivery element may include a radiopaque marker band embedded in or positioned above a wall of the tubular section, with the radiopaque marker band positioned at the abutment point. The radiopaque marker band may have a proximal edge, a distal edge, and a width between the proximal and distal edges. In the delivery configuration, the proximal edge of the radiopaque marker band may be substantially aligned with the distal end of the distal catheter section, such that the radiopaque marker band remains outside the lumen of the distal catheter section. The outer diameter of the tubular section may have a length of at least approximately 5 cm up to approximately 10 cm. The abutment point may be located along at least a portion of the length. The outer diameter may be substantially uniform along the length.The outer diameter can be substantially uneven along its length. The distal point can be located at a distance of at least 5 mm proximal to the most distal end of the catheter delivery element. The first system point can be located at least approximately 5 mm proximal to the distal end of the catheter segment.

[0013] In a related aspect, a coaxial catheter system is described, comprising a catheter and a catheter delivery element. The catheter includes a distal catheter segment with a lumen and a distal end with an opening from the lumen, the lumen having an inner diameter of at least approximately 0.052 inches at the distal end. The catheter includes a proximal extension connected to and extending proximal from the distal catheter segment, the proximal extension being less flexible than the distal catheter segment. The catheter delivery element comprises a tubular segment with an inner diameter of at least approximately 0.014 inches up to approximately 0.024 inches and an outer diameter. The outer diameter has at least one fitting point.The difference between the inner diameter of the distal portion of the catheter and the outer diameter of the tubular portion at the bevel point is no more than approximately 0.010 inches. The catheter delivery element includes a tip section located distal to the at least one bevel point of the tubular portion. The tip section has a length of [missing information] and tapers along at least one portion of its length. The tip section has a distal point located at least 5 mm proximal to the most distal end of the catheter delivery element, and this distal point exhibits a bending force of no more than approximately 0.05 Newtons.

[0014] In a related aspect, a procedure for performing a medical intervention within a patient's cerebral vessel is described. The procedure involves advancing a first assembled coaxial system of devices toward an occlusion within the cerebral vessel. The first assembled coaxial system of devices comprises a first catheter with a first catheter segment having a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end. A first proximal extension is connected to and extends proximal from the first catheter segment, the first proximal extension being less flexible than the first catheter segment. The first assembled coaxial system of devices includes a first delivery element with a flexible, elongated body and a soft, tapered distal tip.At least one portion of the elongated body is positioned within the lumen of the first catheter segment, and the tapered distal tip extends distally to the distal end of the first catheter segment. The procedure involves proximal withdrawal of the first delivery element from the lumen of the first catheter segment and advancement of a second assembled coaxial system of devices through the lumen of the first catheter segment, out of the distal opening of the lumen, and to a location near a proximal surface of occlusion within the cerebral blood vessel. The second assembled coaxial system of devices comprises a second catheter and a second delivery element.The second catheter includes a second catheter segment with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a second proximal extension connected to and extending proximal to the second catheter segment, the second proximal extension being located below the second catheter segment. The second delivery element includes a flexible, elongated body and a soft, tapered distal tip, with at least one portion of the elongated body positioned within the lumen of the second catheter segment and the tapered distal tip extending distal to the distal end of the second catheter segment. The second compound coaxial arrangement of devices is advanced together after the distal end of the second catheter segment extends distal to the petrosal portion of the A.The method involves withdrawing the second delivery element proximally from the lumen of the second catheter segment; applying suction pressure through the lumen of the second catheter segment; anchoring the distal end of the second catheter segment to the occlusion by means of the suction pressure; and exerting a proximally directed force on the second catheter to reduce the sagging of the second catheter relative to the surrounding anatomy while the distal end of the second catheter segment remains anchored to the occlusion.

[0015] The method can further include withdrawing the second catheter from the cerebral blood vessel, wherein the distal end of the second catheter segment is provided with occlusion material.The procedure can further include advancing the first catheter over the second catheter while the distal end of the second catheter segment is anchored to the occlusion by suction pressure. The procedure can further include positioning the distal end of the first catheter segment near the proximal surface of the occlusion. The procedure can further include retracting the second catheter into the lumen of the first catheter; and automatically applying suction pressure through the lumen of the first catheter segment as the second catheter is retracted into the lumen. The suction pressure applied through the lumen of the first catheter segment and the lumen of the second catheter segment can be applied from a single source. The distal end of the second catheter segment can be equipped with occlusion material.

[0015] The procedure may further include withdrawing the second catheter from the lumen of the first catheter while the first catheter maintains suction pressure through the lumen of the first catheter segment. The procedure may further include advancing a guide sheath from an access site, the guide sheath comprising a tubular sheath body with a central lumen, a proximal end, a distal opening, and a connector operatively connected to the proximal end of the sheath body. Advancing the first assembled coaxial catheter system may include advancing the first assembled coaxial catheter system through the guide sheath. The first catheter segment may have an outer diameter configured to form a seal with the central lumen of the guide sheath when suction pressure is applied.The second catheter segment may have an outer diameter configured to form a seal with the lumen of the first catheter when suction pressure is applied. An outer surface of the second catheter segment may seal with an inner surface of the first catheter segment, creating a continuous lumen between the distal opening of the second catheter segment and the proximal end of the guide sheath. The connector may include a single- or double-headed rotary hemostatic valve. Both the first and second assembled coaxial catheter systems may be advanced through the connector. The procedure may further include the guide sheath, advancing the distal opening of the guide sheath to a location in a distal internal carotid artery (ICA).The second catheter may have an inner diameter between 0.054 in and 0.070 in, the first catheter an inner diameter between 0.072 in and 0.088 in, and the guide sheath a diameter between 6 Fr and 8 Fr. The procedure may further include advancing a guidewire through the occlusion. The occlusion need not penetrate during the procedure. The first assembled coaxial catheter system may further include a guidewire. In the assembled state, the guidewire may be positioned within a lumen of the flexible, elongated body of the first delivery element, and the first delivery element may be positioned within the lumen of the first catheter segment such that the tapered distal tip extends distally to the distal end of the first catheter segment, and the guidewire extends distally to the tapered distal tip.An outer surface of the second catheter section can form a seal with an inner surface of the first catheter section, thereby forming a continuous lumen between the distal opening of the second catheter section and the proximal opening of the first catheter section.

[0016] In a related aspect, a procedure for performing a medical intervention within a patient's cerebral vessel is described. The procedure involves advancing a first assembled coaxial catheter system to a location near the proximal surface of an occlusion within the cerebral vessel. The first assembled coaxial catheter system comprises a first catheter and a first delivery element. The first catheter includes a first catheter segment with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a first proximal extension connected to and extending proximal to the first catheter segment, the first proximal extension being located below the first catheter segment.The first delivery element comprises a flexible, elongated body and a soft, tapered distal tip section, with at least one portion of the elongated body positioned within the lumen of the first catheter segment and the tapered distal tip section extending distal to the distal end of the first catheter segment. The first assembled coaxial array of devices is advanced together once the distal end of the first catheter segment is distal to the petrosal portion of the internal carotid artery.The procedure involves proximal withdrawal of the first delivery element from the lumen of the first catheter segment; applying suction pressure through the lumen of the first catheter segment; anchoring the distal end of the first catheter segment to the occlusion via the suction pressure; applying a proximally directed force to the first catheter to reduce the sag of the first catheter relative to the surrounding anatomy while the distal end of the first catheter segment remains anchored to the occlusion; and advancing a second catheter over the first catheter while the distal end of the first catheter segment remains anchored to the occlusion via the suction pressure.The second catheter includes a second catheter segment with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a second proximal extension connected to and extending proximal to the second catheter segment. The second proximal extension is less flexible than the second catheter segment.

[0017] The procedure may further include withdrawing the first catheter from the cerebral blood vessel. The distal end of the first catheter segment may contain occlusion material. The procedure may further include positioning the distal end of the second catheter segment near the proximal surface of the occlusion. The procedure may further include withdrawing the first catheter into the lumen of the second catheter and automatically applying aspiration pressure through the lumen of the second catheter segment as the first catheter is withdrawn into the lumen. The aspiration pressure may be applied through the lumen of the first catheter segment, and the lumen of the second catheter segment is supplied by a single source of aspiration pressure. The distal end of the first catheter may contain occlusion material.The procedure may further include withdrawing the first catheter from the lumen of the second catheter while the second catheter maintains suction pressure through the lumen of the second catheter segment. The procedure may further include advancing a guide sheath from an access site. The guide sheath may comprise a tubular sheath body with a central lumen, a proximal end, a distal opening, and a connector functionally connected to the proximal end of the sheath body. The second catheter segment may include an outer diameter configured to seal with the central lumen of the guide sheath when suction pressure is applied. The first catheter segment may include an outer diameter configured to seal with the lumen of the second catheter when suction pressure is applied.An outer surface of the first catheter segment can form a seal with an inner surface of the second catheter segment, thus creating a continuous lumen between the distal opening of the first catheter segment and the proximal end of the guide sheath. The connector can incorporate a single- or double-headed rotary hemostatic valve. Both the first assembled coaxial catheter system and the second catheter can be advanced through the connector.

[0018] The procedure may include advancing the guide sheath, with the distal opening of the guide sheath being advanced to a site in a distal internal carotid artery (ICA). The first catheter may have an inner diameter between 0.054 in and 0.070 in. The second catheter may have an inner diameter between 0.072 in and 0.088 in. The guide sheath may be between 6 Fr and 8 Fr. The procedure may further include advancing a guidewire across the occlusion. The occlusion need not penetrate during the procedure. An inner surface of the second catheter segment may seal against an outer surface of the first catheter segment, forming a continuous aspiration lumen between the distal opening of the first catheter segment and the proximal opening of the second catheter segment.

[0019] In a related aspect, a system of devices for performing a medical procedure in a patient's cerebral vessel is disclosed, comprising a first catheter and a second catheter. The first catheter has a first catheter section with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a first proximal extension connected to and extending proximal from the first catheter section, the first proximal extension being located below the first catheter section. The second catheter is configured to be positioned coaxially within the lumen of the first catheter section.The second catheter comprises a second catheter segment with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a second proximal extension connected to and extending proximal to the second catheter segment, with the second proximal extension lying below the second catheter segment. The system includes a guide sheath with a tubular sheath body having a central lumen, a proximal end, a distal opening, and a connector operatively connected to the proximal end of the sheath body. A single, common vacuum source is connected to the guide sheath connector and configured to apply suction pressure through the central lumen of the guide sheath, the lumen of the first catheter segment, and the lumen of the second catheter segment.An outer surface of the second catheter section can form a seal with an inner surface of the first catheter section, thereby forming a continuous lumen between the distal opening of the first catheter section and the proximal opening of the second catheter section.

[0020] In a related aspect, a method for performing a medical procedure in a patient's cerebral vessel is disclosed. The method involves advancing a first catheter toward an occlusion within a cerebral blood vessel. The first catheter has a first catheter segment with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a first proximal extension connected to the first catheter segment near the proximal opening, the first proximal extension being located below the first catheter segment. The method includes advancing a second catheter through the lumen of the first catheter segment, out of the distal opening of the lumen, and to a location near a proximal surface of the occlusion within the cerebral vessel.The second catheter comprises a second catheter segment with a lumen, a proximal opening into the lumen, a distal opening from the lumen, and a distal end; and a second proximal extension connected to the second catheter segment near the proximal opening, the second proximal extension being located below the second catheter segment. The procedure includes forming a seal between an outer diameter of the second catheter segment and an inner diameter of the first catheter segment; and applying suction pressure through at least one of the lumens of the second catheter segment, the lumen of the first catheter segment, or a continuous aspiration lumen formed by the lumens of the first and second catheter segments. The continuous aspiration lumen extends from the distal end of the second catheter segment to the proximal opening of the first catheter segment.The procedure can further include anchoring the distal end of the second catheter segment to the occlusion using aspiration pressure. The procedure can further include applying a proximally directed force to the second catheter to reduce its sagging relative to the surrounding anatomy while keeping the distal end of the second catheter segment anchored to the occlusion.

[0021] In some variants, one or more of the following measures may be included, in any possible combination, in the aforementioned methods, facilities, equipment, and systems. Further details regarding the methods, facilities, equipment, and systems are set forth in the accompanying drawings and the description below. Additional features and advantages will become apparent from the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] These and other aspects are now described in detail with the following drawings. In general, the illustrations are neither absolutely nor comparatively to scale, but serve only for clarification. Furthermore, the relative arrangements of features and elements may be changed for the purpose of clear representation. Fig. Figures 1A-1B illustrate the course of the terminal internal carotid artery to the cerebral vascular system; Fig. Figure 1C illustrates the aortic arch including the branches of the brachiocephalic artery (BT), the left common carotid artery (LCC) and the left subclavian arteries (LSA) from the aortic arch (AA); Fig. 2A is an exploded view of an implementation of an aspiration catheter system; Fig. 2B is an assembled view of the aspiration catheter system made of Fig. 2A; Fig. 2C is a detailed view of Fig. 2A, taken at the CC district; Fig. 2D illustrates an implementation of an arterial device with a distal occlusion balloon; Fig. Figure 3 is a side view of an implementation of a spinal distal access catheter; Fig. Figure 4A is a cross-sectional view of a first implementation of a proximal control element of a spinal distal access catheter; Fig. Figure 4B is a cross-sectional view of another implementation of a proximal control element of a spinal distal access catheter; Fig. 4C is a cross-sectional view of the proximal control element from Fig. 4A within a working lumen of an access sleeve; Fig. 4D is a cross-sectional view of the proximal control element from Fig. 4B within a working lumen of an access sheath with a catheter delivery element extending therein; Fig. 4E is a schematic cross-sectional view showing the surface of the proximal control element. Fig. 4A and the proximal control element from Fig. 4B within the working lumen of an access sleeve made of Fig. 4D compares; Fig. 4F-4G are schematic cross-sectional views comparing trapezoidal and D-shaped proximal extensions relative to a working lumen of an access airlock; Fig. 5A is a side view of an implementation of a spinal distal access catheter; Fig. 5B is a top view of the spinal distal access catheter from Fig. 5A; Fig. 5C is a cross-section of the spinal distal access catheter along line CC of Fig. 5B; Fig. 5D is a cross-sectional view of the spinal distal access catheter along the DD line. Fig. 5B; Fig. 5E-5F are partial perspective views of the spinal distal access catheter from Fig. 5A; Fig. Figure 6A is a side view of an implementation of a spinal distal access catheter; Fig. Figure 6B is a top view of the spinal distal access catheter. Fig. 6A; Fig. 6C is a cross-section of the spinal distal access catheter along line CC of Fig. 6B; Fig. 6D is a cross-sectional view of the spinal distal access catheter along the DD line. Fig. 6B; Fig. 6E-6F are partial perspective views of the spinal distal access catheter from Fig. 6A; Fig. 7A is a side view of an implementation of a catheter feeder element; Fig. 7B is a cross-sectional view of the catheter delivery element made of Fig. 7A; Fig. 7C is a detailed view of Fig. 7B along circle CC; Fig. 7D is a side view of another implementation of a catheter feeder element; Fig. Figure 7E is a cross-sectional view of an implementation of a proximal section of the catheter feeder element made of Fig. 7D; Fig. Figures 7F-7J show different views of an implementation of a proximal hub for connecting to the in Fig. 7E proximal section shown; Fig. Figure 8A is a side view of a catheter implementation; Fig. Figure 8B is a schematic sectional view of the distal end of the catheter. Fig. 8A; Fig. Figure 8C is a schematic cross-sectional view of the distal end of the catheter. Fig. 8A; Fig. Figures 9A-9C show different views of a proximal extension connector; Fig. 10A is a schematic cross-sectional view of an implementation of a catheter feeder element; Fig. Figure 10B is a schematic cross-sectional view of a distal end region of the catheter delivery element made of Fig. 10A; Fig. Figure 10C is a schematic cross-sectional view of a region of the catheter delivery element made of Fig. 10A; Fig. 11 is a schematic representation of an implementation of a catheter aligned with an implementation of a catheter feed element, illustrating staggered changes of material; Fig. Figure 12 is a schematic representation of an implementation of a bending force testing system; Fig. Figure 13A is a schematic representation of a distal end region of a catheter delivery element extending through a catheter and of points that are tested for bending force; Fig. Figure 13B illustrates the bending force in Newtons (N) along the length of a catheter system that includes a catheter and a catheter feeder in the feeder configuration (dashed line), the catheter feeder alone (dashed dotted-dashed line), and the catheter alone (solid line). Fig. Figure 14A is a diagram of the bending forces along the length of a catheter system formed from a catheter feeder element configured to extend through a catheter with an inner diameter of 0.054 inches; Fig. Figure 14B is a diagram of the bending forces along the length of a catheter system formed from a catheter feeder element configured to extend through a catheter with an inner diameter of 0.070 inches; Fig. Figure 14C is a diagram of the bending forces along the length of a catheter system formed from a catheter feeder element configured to extend through a catheter with an inner diameter of 0.070 inches; Fig. Figure 14D is a diagram of the bending forces along the length of a catheter system formed from a catheter feeder element configured to extend through a catheter with an inner diameter of 0.088 inches; Fig. 14E is a diagram of the bending forces along a length of another catheter system; Fig. Figure 15 illustrates an implementation of a nested catheter system.

[0023] It should be understood that the drawings are only examples and are not to scale. It is understood that the devices described herein may include features that are not necessarily shown in every figure. DETAILED DESCRIPTION

[0024] Navigating the carotid anatomy to treat various neurovascular pathologies at the level of the cerebral arteries, such as acute ischemic stroke (AIS), requires catheter systems with superior flexibility and ease of insertion. The internal carotid artery (ICA) originates from the bifurcation of the common carotid artery (CCA) at the level of the intervertebral disc between vertebrae C3 and C4. As shown in FIG. IA, the course of the ICA is divided into four parts: the cervical part Cr, the petrosal part Pt, the cavernous part Cv, and the cerebral part Cb. In the anterior circulation, the continuously tortuous terminal carotid artery is fixed in position by bony elements. The cervical carotid artery Cr enters the petrous bone and is fixed by its bony encasing in a series of turns.The cavernous carotid artery is an artery that passes through a venous bed, the cavernous sinus. While flexible, it is fixed upon exiting the sinus by another bony element that surrounds and secures the entrance to the cavity. Due to these bony fixation points, the petrous and cavernous carotid arteries (Pt and Cv) and their protruding segments are relatively uniform in their winding. The carotid siphon (CS) is an S-shaped portion of the terminal ICA. The CS begins at the posterior bend of the cavernous ICA and terminates at the ICA bifurcation into the anterior cerebral artery (ACA) and the middle cerebral artery (MCA). The ophthalmic artery arises from the cerebral ICA, which is a common site for catheter entrapment during access to the anterior circulation.The MCA is initially defined by a single M1 segment, then branches into two or three M2 segments, and further to form M3 segments. These points, where the catheter can become stuck, can significantly prolong the time required to restore cerebral blood flow, a disadvantage with serious consequences in the treatment of AIS.

[0025] With increasing age, the large blood vessels often enlarge and lengthen. The proximal and distal fixed internal carotid arteries frequently become tortuous with age. The common carotid artery (CCA) is relatively fixed within the thoracic cavity, as it exits the neck through the clavicle. The external and internal carotid arteries (ECA and ICA) are not fixed relative to the common carotid artery (CCA) and therefore develop tortuousness with age, resulting in elongation of the entire carotid system. This can cause them to elongate and develop kinks and twists, or in the worst case, form a complete loop, also known as a "neck loop."If catheters used to cross these kinked or curved areas are too stiff or inflexible, these areas can undergo a straightening that can cause the vessel to twist around itself or form a "barber's rod," resulting in focused kinks and folds of the vessel. This type of extreme twisting can also significantly prolong the time required to restore blood flow to the brain, particularly in older adults. In certain circumstances, the twisting of the vessels around themselves or a kink in the untwisted artery can reduce normal antegrade flow to the point of cessation, leading to ischemia. Treating kinks or loops in vessels such as the cervical ICA can also increase the duration of the procedure.

[0026] A significant drawback of current catheter systems for stroke interventions is the time required to restore cerebral blood flow, including the time needed to access the occlusion(s) in the cerebral artery and the time required to completely remove the occlusion. Since more than one attempt is often necessary to fully clear the occlusion, reducing the number of attempts, as well as the time spent exchanging devices for additional attempts, is a critical factor in minimizing the overall time. Furthermore, each attempt carries a potential procedural risk due to the insertion of the device into the delicate vascular system of the brain.Another limitation is the need for multiple operators to deliver and effectively manipulate long triaxial systems with multiple RHVs, typically used with conventional guide and distal access catheters.

[0027] This document describes catheter systems and procedures for the treatment of various neurovascular pathologies, such as acute ischemic stroke (AIS). The systems described herein provide rapid and easy access to the distal target anatomy, particularly the tortuous anatomy of the cerebral vessels, at a single manipulation point. The medical procedures, devices, and systems described herein enable navigation through complex, tortuous anatomies to perform rapid and safe aspiration and removal of cerebral occlusions for the treatment of acute ischemic stroke. The medical procedures, devices, and systems described herein can also be used to deliver intracranial medical devices, with or without aspiration, for the removal of cerebral occlusions in the treatment of acute ischemic stroke.The systems described herein can be particularly useful for the treatment of AIS, regardless of whether a user intends to perform aspiration alone as the primary treatment for AIS. Furthermore, the extreme flexibility and availability of the distal access catheter systems described herein allow the catheters to conform to the tortuous anatomy rather than exerting straightening forces that create a new anatomy. The distal access catheter systems described herein can navigate tortuous loops while maintaining the natural curves of the anatomy, thereby reducing the risk of straightening the vessels. The distal access catheter systems described herein can thus create a secure channel through the neurovasculature that maintains the natural torsional curvature of the anatomy, allowing other catheters (e.g., larger-diameter aspiration catheters) to traverse it.

[0028] The devices, systems, and methods of use described herein relate to the devices, systems, and methods of use described herein in U.S. Publication No. 2013 / 0035628, filed on August 3, 2012, and may be used in combination and alternatively to U.S. Publication No. 2015 / 0173782, filed on December 19, 2014, and U.S. Publication No. 2016 / 0220741, filed on February 4, 2016. The disclosures of each of these publications are incorporated herein in their entirety by reference.

[0029] Although some implementations described herein are specifically related to accessing neurovascular anatomy for the application of aspiration, the systems and procedures described herein should not be limited to this purpose and may be applicable to other uses. For example, the catheter systems described herein can be used to deliver working devices to a target vessel of coronary anatomy or other vascular anatomy. When the terms “distal access catheter” or “aspiration catheter” are used herein, the catheter may be used for aspiration, for delivering fluids to a treatment site, or as a carrier or distal access point, providing a channel to facilitate and guide the delivery or exchange of other devices, such as a guidewire or interventional devices like stent retrievers.Alternatively, the access systems described herein may also be useful for accessing other parts of the body outside the vascular system. Similarly, if the working device is described as an expandable cerebral treatment device, stent retriever, or self-expanding stent, other interventional devices may be delivered using the delivery systems described herein.

[0030] Referring to the drawings, the Fig. 2A-2B a System 100 including devices for accessing and removing a cerebral occlusion for the treatment of an acute ischemic stroke. The System 100 can be a single-operator system, allowing all components and systems to be deployed and used jointly by one operator via a single manipulation point requiring minimal hand movement. As described in more detail below, all wire and catheter manipulations can be performed on or in the immediate vicinity of a single rotating hemostatic valve (RHV) 434 or more than one single RHV located at the same location in the same device. The System 100 can include one or more catheter delivery systems 150, each comprising a catheter 200 and a catheter advancement element 300. The catheter delivery system 150 is configured to advance through an access guide sheath 400.The Catheter 200 is configured to be received by the Guide Sheath 400 and is designed for exceptional deliverability. The Catheter 200 can be a spinal distal access catheter that is coaxial with a lumen of the Guide Sheath 400, thereby increasing the inner diameter within the conduit. The Catheter 200 can be advanced using a Catheter Advancer 300, which is inserted through a lumen 223 of the Catheter 200. The System 100 can be a distal access system capable of providing variable length from the entry point at the percutaneous arteriotomy (e.g., the femoral artery or other entry point) to the target control point of the distal catheter. Conventional distal access systems for stroke interventions typically involve a long guide sheath or guide catheter that is inserted through a shorter "advancement sheath" (e.g., a 400-inch guide sheath).The long guide sheath (11–30 cm long) is placed in the groin. It is typically positioned in the ICA to assist neurovascular interventions, including stroke embolectomy (sometimes called thrombectomy). For additional support, it may be advanced to the bony petrous end and, in rare cases, to the cavernous, clinoid, or supraclinoid end of the ICA, if feasible. To reach targets in the M1 or M2 distribution for ADAPT / MAT or Solumbra / SMAT approaches, an additional catheter may be advanced through the long guide sheath. These catheters are usually large-bore aspiration catheters, which may be, for example, 130 cm or longer.As described in more detail below, the distal access systems described herein can be 100 shorter, for example, only 115 cm long, when measured as a system from the access point, usually the common femoral artery. Furthermore, a single operator can use the systems described herein by inserting them through a single rotary hemostatic valve (RHV) 434 on the guide sheath 400, or through more than one RHV located at the same position in the same device, such as a double-headed RHV. Thus, a procedure that previously required two people can now be performed by one person.

[0031] The various components of the different systems will now be described in more detail. Access guide sleeve

[0032] Referring to the Fig. In 2A-2D, the distal access system 100 can comprise an access guide sheath 400 with a body 402 having a working lumen guide extending from a proximal hemostasis valve 434, connected to a proximal end region 403 of the body 402, to a distal opening 408 of a distal end region. The working lumen is configured to accommodate the catheter 200, allowing a distal end of the catheter 200 to extend beyond a distal end of the sheath 400 through the distal opening 408. The guide sheath 400 can be used to accommodate the catheters described herein as well as a variety of devices known in the art.For example, the devices can be configured to provide thrombotic treatments and can include large-diameter catheters, aspiration embolectomy (or thrombectomy) catheters, advanced catheters, wires, balloons, and retrievable structures such as retrievable coil-tip stents (“stent retrievers”). The Guide Sheath 400 can be used with the Catheter 200 to perform distal aspiration, as described in more detail below.

[0033] Guide Sheath 400 can be any of the various commercially available guide sheaths. For example, Guide Sheath 400 can have an inner diameter between 0.087 inches and 0.089 inches, such as the Cook SHUTTLE 6F (Cook Medical, Inc., Bloomington, IN), Terumo DESTINATION 6F (Terumo Europe NV), Cordis VISTA BRITE TIP (Cordis Corp., Hialeah, FL), Penumbra NEURON MAX 088 (Penumbra, Inc., Alameda, CA), Stryker Infinity (Stryker Neurovascular, Fremont, CA), or a comparable commercially available guide sheath. Generally, guide sheath sizes are specified herein using the French scale (F). For example, a guide sheath is specified as 6 French, and the inner diameter of this guide sheath can accommodate a catheter with an outer diameter of 6F, which is approximately 1.98 mm or 0.078 inches.A catheter can be described herein with a specific size in French to indicate the compatibility of its inner diameter with the outer diameter of another catheter. A catheter can also be described herein with a specific size in French to indicate that its outer diameter is compatible with another catheter having a specific inner diameter.

[0034] The guide sheath 400 is available in various sizes to accommodate different devices, such as the Catheter 200, and can be customized to the user's preferences. The working lumen of the guide sheath 400 can be dimensioned to accommodate the respective Catheter 200 in a sliding fit. Generally, it is desirable to minimize the overall size of the vessel insertion site by limiting the outer diameter of the guide sheath 400 to less than 0.122 inches. It is also desirable to select appropriate outer and inner diameters to ensure a good sliding fit between the Catheter 200 and the guide sheath 400. The working lumen of the guide sheath can have an inner diameter that is at least 0.001 inches larger than the maximum outer diameter of a Catheter 200 it is intended to accommodate, especially if the Catheter 200 is to be used for aspiration.The working lumen can have an inner diameter dimensioned to accommodate at least 6 French catheters (1.98 mm or 0.078 in.), at least 6.3 French catheters (2.079 mm or 0.082 in. outer diameter), at least 7 French catheters (2.31 mm or 0.091 in. outer diameter), or 8 French catheters (2.64 mm or 0.104 in. outer diameter), or larger catheters. However, the inner diameter of the Guide Sheath 400 may be smaller or larger to accommodate other catheter sizes. Regardless of length and inner diameter, the Guide Sheath 400 is kink-resistant during distal advancement through the vessels.

[0035] The aspiration catheters described herein may have an inner diameter between 0.054 in and 0.088 in. If the catheter 200 has an inner diameter of 0.088 in and a maximum outer diameter between 0.105 in and 0.107 in, the guide sheath 400 may, in turn, have a working lumen with an inner diameter between 0.106 in and 0.108 in. Generally, the difference or gap between the maximum outer diameter of the catheter 200 and the inner diameter of the guide sheath 400 is less than approximately 0.002 in, for example, between 0.001 in and 0.002 in. The small gap between the maximum outer diameter of the catheter 200 and the inner diameter of the guide sheath 400 may be localized. This means that the small gap between the two can only represent a fraction of the cylindrical length of the catheter 200 and the sheath 400.Thus, the OD-ID difference between the catheter 200 and the guide sheath 400 can be greater than or equal to 0.002 inches along a first cylindrical length where the two devices overlap during use, and less than 0.002 inches along another cylindrical length of the overlap, providing a local area of ​​low clearance within the overlap. This allows for practical relative sliding capability and adequate sealing when deployed under aspiration pressure, as described in more detail below. For example, a distal portion of the guide sheath 400 may have a first inner diameter at a distal end and a second, different inner diameter at a proximal end, so that the low clearance of the sliding fit with the catheter 200 varies along its length.In some implementations, the catheter 200 has a first outer diameter at a distal end and a second, larger outer diameter at a proximal end. The second, larger outer diameter may be less than 0.002 inches of the inner diameter of the sheath 400, and the first outer diameter may be greater than 0.002 inches of the inner diameter of the sheath 400. This provides a tighter overall fit between the guide sheath 400 and the proximal end of the catheter 200 at the location of this second, larger outer diameter.

[0036] With regard to the Fig. In 2A-2D, the sheath body 402 can extend from a proximal furcation or a rotating hemostatic valve (RHV) 434 at a proximal end region 403 to a tip 406 at a distal end of the body 402. The proximal RHV 434 can include one or more lumens molded into a connector to connect to the working lumen of the body 402 of the guide sheath 400. The working lumen can accommodate the catheter 200 and / or a variety of working devices directed at a target anatomy. The RHV 434 can be made of thick-walled polymer tubing or reinforced polymer tubing. The RHV 434 enables the introduction of devices through the guide sheath 400 into the vascular system while simultaneously preventing blood loss and the ingress of air into the guide sheath 400.The RHV 434 can be an integral part of the guide sheath 400, or the guide sheath 400 can terminate at one proximal end in a female Luer adapter to which a separate hemostasis valve component, such as a passive sealing valve, a Tuohy-Borst valve, or a rotary hemostasis valve, can be attached. The RHV 434 can have an adjustable opening large enough to remove devices with clots adhering to the tip without the clot detaching from the RHV 434 during removal. Alternatively, the RHV 434 can be removable, as when a device is removed from the sheath 400, to prevent clot detachment from the RHV 434. The RHV 434 can be a double RHV.

[0037] The RHV 434 can form a Y-connector at the proximal end 403 of the sheath 400, such that the first port of the RHV 434 is used to introduce a working catheter into the working lumen of the sheath 400, and a second port in the arm 412 is used for another purpose. For example, a syringe or other device can be connected to arm 412 via a connector 432 to deliver a forward infusion, a flush line for contrast medium or saline injections through the body 402 toward the tip 406 and into the target anatomy. Arm 412 can also be connected to an aspiration source 505 (see Fig. 2B). The aspiration source 505 can be an active aspiration source, such as an aspiration pump, a standard or locking syringe, a hand aspirator, a hospital suction device, or the like, configured to generate suction through the working lumen. In one embodiment, the aspiration source 505 is a locking syringe (for example, a VacLok syringe) attached to a flow controller or regulator. The syringe plunger can be retracted by the user into a locked position, while the connection to the flow line is closed prior to an embolectomy step of the procedure. During the procedure, when the catheter tip is near or at the site of occlusion, the user can open the connection to the suction syringe.This enables maximum transmission of the suction force applied through the working lumen of the guide sheath 400 and each catheter extending through the sheath 400, which in turn connects to the vessel at its distal end. Aspiration can be performed quickly by a single user at a single, shared source. In another implementation, the arm 412 can be connected to an aspiration source 505, which is a pump configured to apply an aspiration pressure through the working lumen of the guide sheath 400. The single, shared aspiration source is sufficient to effect aspiration throughout the entire system 100, even if multiple aspiration catheters 200 are nested within each other through the working lumen of the guide sheath 400.The arm 412 can also allow the guide sheath 400 to be flushed with saline solution or radiopaque contrast medium during a procedure. The working lumen can extend from a distal end to a proximal working port of the proximal end region 403 of the sheath body 402.

[0038] The length of the catheter body 402 is configured so that the distal tip 406 of the body 402 can be positioned as distally as possible in the internal carotid artery (ICA) during a transfemoral approach, for example, with additional length available for adjustments. In some implementations (e.g., femoral or radial percutaneous access), the length of the body 402 can be in the range of 80 to 90 cm or longer, for example, up to approximately 100 cm or up to approximately 105 cm. In some implementations, the length of the body 402 is suitable for transcarotid access to the carotid bifurcation in the range of 20 to 25 cm. In other implementations, the length of the body 402 is suitable for percutaneous transcarotid access to the CCA or proximal ICA and is in the range of 10 to 15 cm.The Body 402 is configured to follow and navigate the bends of the vascular system without kinking, collapsing or causing vascular trauma, even when subjected to high suction forces, for example.

[0039] In some implementations, the system 100 may further include a selection tool for advancing the guide sleeve 400. The selection tool may have an outer diameter configured to fit within the working lumen of the guide sleeve 400, such that a distal end of the selection tool extends a distance distal to the distal end of the guide sleeve 400. The outer diameter of the selection tool sufficiently fills the inner diameter of the working lumen of the guide sleeve 400 to minimize the lip at the distal opening 408 of the guide sleeve 400. For example, the inner diameter of the working lumen of the guide sleeve 400 may be between approximately 0.087" and approximately 0.113". In this case, the outer diameter of the selection tool may be approximately 0.006" below this value, or between approximately 0.081" and approximately 0.107".The brachiocephalic origin (BT) is typically a very prominent branch from the aortic arch (AA) for a transfemorally placed catheter targeting right-sided cerebral perfusion (FIG. IC). A catheter runs from the femoral artery through the iliac circulation into the descending aorta (DA). The catheter rotates as it approaches the aortic arch (AA) and, via the branching points of other major vessels, reaches the brachiocephalic origin (BT), which represents the furthest reach of the major vessels of the aortic arch (AA). Fig. Figure 1C illustrates the substantial and unavoidable S-tum that results from this anatomy. A catheter must traverse this S-tum along an insertion path from a point in the femoral artery to reach the internal carotid artery (ICA). The left ICA frequently originates from the brachiocephalic artery and therefore presents a similar challenge, potentially creating an even narrower S-tum. If the left ICA has a typical origin between the brachiocephalic artery (BT) and the left subclavian artery (LSA), the reach may be less extensive, but a less severe S-tum will still be formed. The distal end of the selection tool may be tapered and / or modified in shape to provide support and guidance for advancing the Sheath 400 around this tum into the ICA.In some implementations, the selection tool may have a Bernstein Select-type or Simmons-type catheter tip with reverse curvature, as is known in engineering.

[0040] The tip 406 of the guide sleeve 400 can have the same or a similar outer diameter as a section of the body 402 leading to the distal end. Accordingly, the tip 406 can have a distal surface orthogonal to a longitudinal axis passing through the body 402, and the distal surface can have an outer diameter substantially equal to a cross-sectional outer dimension of the body 402. In one implementation, the tip 406 includes a chamfer, fillet, or taper, causing the diameter of the distal surface to be slightly smaller than the cross-sectional dimension of the body 402.In another implementation, the tip 406 can be an elongated tubular section extending distally to a region of the body 402 and having a uniform outer diameter, such that the elongated tubular section has a reduced diameter compared to the uniform outer diameter of the body 402. Thus, the tip 406 can be elongated or blunt in shape. Accordingly, the tip 406 can be configured to move smoothly through a vascular system and / or to dilate vascular constrictions as it moves through the vascular system. The working lumen can have a distal end forming a distal opening 408.

[0041] The guide sleeve 400 can enclose a tip 406 that tapers from a section of the body 402 leading to the distal end. That is, an outer surface of the body 402 can have a diameter that decreases from a larger dimension to a smaller dimension at a distal end. For example, the tip 406 can taper from an outer diameter of approximately 0.114 inches to approximately 0.035 inches, or from approximately 0.110 inches to approximately 0.035 inches, or from approximately 0.106 inches to approximately 0.035 inches. The taper angle of the tip 406 can vary depending on the length of the tapered tip 406. For example, in some implementations, the tip 406 tapers from 0.110 inches to 0.035 inches over a length of approximately 50 mm.

[0042] In one implementation, the guide sheath 400 encloses one or more radiopaque markers 411. The radiopaque markers 411 may be located near the distal tip 406. For example, a pair of radiopaque bands may be pressed, painted, embedded, or otherwise arranged in or on the body 402. In some implementations, the radiopaque markers 411 include a barium polymer, a tungsten-polymer mixture, a tungsten-filled, or a platinum-filled marker, which maintains the flexibility of the distal end of the device and improves the transition along the length of the guide sheath 400 and its buckling strength. In some implementations, the radiopaque marker 411 is a tungsten-containing PEBAX or polyurethane that is heat-welded to the body 402. The markers 411 are shown in the figures as rings around the circumference of one or more regions of the body 402.The markers 411 can also have other shapes or form a variety of patterns that provide the operator with an orientation regarding the position of the distal opening 408 within the vessel. Accordingly, an operator can visualize the position of the distal opening 408 under fluoroscopy to confirm that the distal opening 408 is aligned with a target anatomy where a catheter 200 is to be placed. For example, radiopaque markers 411 allow an operator to rotate the body 402 of the guide sheath 400 at an anatomical access point, such as a patient's groin, so that the distal opening provides access to an ICA for subsequent working devices, such as catheters and wires, advanced to the ICA. In some implementations, the radiopaque markers 411 include platinum, gold, tantalum, tungsten, or any other substance visible under an X-ray fluoroscope.Each of the various components of the systems described herein may include radiopaque markers.

[0043] In some implementations, the guide sheath 400 may exhibit similar characteristics to other sheaths used in carotid access and AIS procedures, with respect to flexibility, radiopaqueness, column strength, and flexibility. The inner linings may be made of a low-friction polymer such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene) to provide a uniform surface for advancing devices through the inner lumen. An outer sheath material may impart mechanical integrity to the inner linings and may be made of materials such as PEBAX, thermoplastic polyurethane, polyethylene, nylon, or the like. The body 402 may incorporate a hydrophilic coating. A third layer may be incorporated to provide reinforcement between the inner lining and the outer sheath.The reinforcing layer can prevent flattening or kinking of the inner lumen of body 402, allowing unimpeded navigation of the device through bends in the vascular system and preventing aspiration or backflow. Body 402 can be reinforced circumferentially. The reinforcing layer can be made of metal such as stainless steel, nitinol, nitinol braid, spiral tape, spiral wire, cut stainless steel, or the like, or of a rigid polymer such as PEEK. The reinforcing layer can be a structure such as a coil, braid, or tube that has been laser-cut or machine-cut to be flexible. In another implementation, the reinforcing layer can be a cut hypotub, such as a nitinol hypotub or cut rigid polymer, or the like.The outer sheath of body 402 can be made of materials that become progressively softer towards the distal end. The flexibility of body 402 can vary along its length, increasing towards the distal section. This variability in flexibility can be achieved in several ways. For example, the hardness and / or material of the outer sheath can be altered in different sections. A less hard material can be used in a distal section of the guide sheath than in other sections. Alternatively, the wall thickness of the sheath material can be reduced and / or the density of the reinforcing layer varied to increase flexibility. For example, the spacing of the coil or braid can be stretched, or the cutting pattern in the tubing can be varied to achieve greater flexibility.Alternatively, the reinforcement structure or materials can change along the length of the mantle body 402. In another implementation, there is a transition section between the most distal flexible section and the proximal section, with one or more sections of differing flexibility between the most distal section and the remainder of the mantle body 402. In this implementation, the most distal section is approximately 2 cm to approximately 5 cm long, the transition section is approximately 2 cm to approximately 10 cm long, and the proximal section occupies the remainder of the mantle length.In some implementations, the proximal region of body 402 may be formed from a material such as nylon, a region of body 402 distal to the proximal region of body 402 may have a material hardness of 72D, while further distal regions may be increasingly flexible and may be formed from materials with a material hardness of 55D, 45D, 35D, extending towards the distal tip 406, which may, for example, be formed from a material with a material hardness of 35D.

[0044] The working lumen of the guide sheath 400 can have different inner diameters configured to accommodate catheters 200 with varying outer diameters. In some implementations, the working lumen of a first guide sheath 400 can have an inner diameter dimensioned to accommodate a 6F catheter, and the working lumen of a second guide sheath 400 can have an inner diameter dimensioned to accommodate an 8F catheter. The guide sheaths 400 can accommodate catheters with an outer diameter that exactly matches the inner diameter of the guide sheath 400 over at least one length. The guide sheath 400 (as well as any other components used with the sheath 400) can be an over-the-wire (OTW) or quick-change device, which is described in more detail below.

[0045] The sheath 400 can enclose a body 402, which is generally formed from three layers, including a sliding inner lining, a reinforcing layer, and an outer sheath layer. The reinforcing layer may include a braid to ensure good torque transmission, optionally overlaid with a coil to provide good buckling resistance. In sheaths where the reinforcing layer consists only of a braid, the polymers of the outer sheath layer may generally have greater hardness and thickness to avoid buckling problems. The wall thickness of such sheaths consisting only of a braid with a thicker polymer may be about 0.011 inches. The wall thickness of the sheaths 400 described herein with a braid and a coil overlay provides both torsion and buckling resistance and may generally be thinner, for example, about 0.0085 inches.The outer diameter of the proximal end can thereby be reduced to below 0.112 inches, for example, to approximately 0.107 inches. Generally, it is advantageous to limit the overall outer diameter of the Guide Sheath 400 so that the entry wound into the patient (e.g., at the femoral artery) can be kept to a minimum size. Thus, the Guide Sheath 400 is a high-performance sheath 400 that exhibits good torque and kinking strength and, due to its thinner wall, provides an overall lower profile for the system. The thinner wall and lower profile allow for a smaller insertion opening through the vessel without compromising the overall lumen size. In some implementations, the wall thickness of the Guide Sheath 400 may decrease gradually towards the distal end of the sheath compared to the proximal end.

[0046] The system can incorporate localized points of low clearance between the guide sheath 400 and the catheter 200 extending through it. These localized points of low clearance can provide a localized seal between the structures. In some implementations, the localized seal may be located near the distal end region of the guide sheath 400, and in other implementations, the localized seal may be located at a distance from the distal end of the guide sheath 400. The catheter 200 may have an increased outer diameter near a proximal end region, creating a cylindrical section of the catheter that forms a tight fit (e.g., less than approximately 0.002 inches clearance) with the inner diameter of the guide sheath 400. The length of this low-clearance sealing section can vary and depends on the overall clearance between the inner and outer diameters.Larger differences between the inner and outer diameters (i.e., a larger gap) can provide sufficient sealing at suction pressures by increasing the length of the cylindrical sealing area. Smaller differences between the inner and outer diameters (i.e., a smaller gap) can provide sufficient sealing at suction pressures, even with a shorter cylindrical length. In other words, a shorter sealing zone can have a tighter fit or a smaller gap, while a longer sealing zone does not necessarily require such a tight fit and can have a larger gap.

[0047] The guide sheath 400 may also include additional local sealing points as the catheter extends through its working lumen. In some implementations, the localized seal may be located at a distance from the distal end 406 of the sheath 400. In some implementations, a localized seal may be located at the distal end 406 of the sheath 400. For example, the guide sheath 400 may include a distal tip 406 designed to seal well with the outer diameter of a catheter extending through its working lumen. The distal tip 406 may be formed from a soft material that lacks a lining and reinforcing layers. The lubricating lining layer and the reinforcing layer may extend over most of the body 402, except for a length of the distal tip 406 (see Fig. 2C). The length of this unlined, unreinforced portion of the distal tip 406 of the sheath 400 can vary. In some implementations, the length is between approximately 3 mm and approximately 6 mm of the distal end of the sheath 400. Thus, the lining 409 of the sheath 400 can terminate at least approximately 3 mm from the distal end of the sheath 400, with the last 3 mm consisting of unlined soft material forming the distal tip 406. In some implementations, the ends of the coil and braid of the reinforcement layer feature a radiopaque marker 411, such as a marker band, positioned near the distal end of the sheath 400, which holds the ends in place. The lining layer 409 can extend at least one length distal to the marker band 411 before terminating, for example, a length of approximately 1 mm.The offset end of the wall layers can facilitate the transition from the marker band 411 to the soft material 407 of the distal tip 406. The soft material 407 can extend beyond the lining layer 409. The uncoated soft material 407 forming the distal tip 406 can be a PEBAX material with a hardness of not more than approximately 40D, not more than approximately 35D, not more than approximately 62A, or not more than approximately 25D. The softness of the material and the length of this uncoated distal tip 406 of the sheath 400 can vary. In general, the material is soft enough to be compressed to the outer diameter of the catheter 200 extending through the lumen of the sheath 400, as if a vacuum were applied through the lumen.The length of this unlined, unreinforced area 407 of the distal tip 406 is long enough to provide a good seal, but not so long as to cause problems with wrinkling or folding during the relative sliding between the sheath 400 and the catheter 200, which could block the lumen of the sheath or impair the sliding ability of the catheter 200 within the lumen of the sheath.

[0048] The distal tip 406 may have an inner diameter that approximates the outer diameter of the catheter 200 extending through the sheath 400. In some implementations, the inner diameter of the distal tip 406 may vary depending on the size of the catheter being used. For example, the inner diameter of the sheath at the distal tip 406 may be approximately 0.106 inches if the outer diameter of the catheter near the proximal end is approximately 0.101 inches, resulting in a difference of approximately 0.005 inches between the diameters. When a vacuum is applied, the soft, unlined, and unreinforced distal tip 406 may move to eliminate this 0.005-inch gap and, as the catheter 200 is advanced from its distal opening 408, compress to the outer diameter of the catheter 200 near its proximal end region.The difference between the inner diameter of the distal tip 406 and the outer diameter of the catheter can range from approximately 0.002 in to 0.006 in. The inner diameter of the distal tip 406 can also be tapered such that the inner diameter at the most distal end of the opening 408 is only 0.001 in to 0.002 in larger than the outer diameter of the proximal end of the catheter 200 extending through the working lumen. In some implementations, the distal tip 406 is shaped such that its walls are chamfered at an angle of approximately 60 degrees relative to the central axis of the sheath 400.

[0049] In some cases, it is desirable for the sheath body 402 to also be able to occlude the artery in which it is positioned, for example, during procedures that could cause distal embolisms. Occluding the artery stops the antegrade blood flow, thereby reducing the risk of distal embolisms that can lead to neurological symptoms such as TIA or stroke. Fig. Figure 2D shows an arterial device or sheath 400 with a distal occlusion balloon 440, which, when inflated, occludes the artery at the position of the distal tip 406 of the sheath. At any point during a procedure, for example, during the removal of an occlusion by aspiration and / or the delivery of a stent retriever or other interventional device, the occlusion balloon 440 can be inflated to occlude the vessel and reduce the risk of distal embolism in the cerebral vessels. In addition to the working lumen of the sheath 400, the sheath 400 can include an inflation lumen configured for delivering fluid to inflate the occlusion balloon 440. The inflation lumen can, for example, fluidically connect the balloon 440 to the arm 412 on the proximal adapter.This arm 412 can be attached to an inflation device, such as a syringe, to inflate the balloon 440 with a liquid when vascular occlusion is desired. The arm 412 can be connected to a passive or active aspiration source to further reduce the risk of distal embolism.

[0050] According to some implementations, the length of the 400 mm guide sheath is sufficient to access the target anatomy and exit the arterial access site with additional length outside the patient's body for adjustments. For example, the 400 mm guide sheath (regardless of whether it has a 440 mm distal occlusion balloon) may be long enough to access the petrosal ICA from the femoral artery, leaving additional length available for adjustments.

[0051] The gap between the guide sheath 400 and the catheter 200 can be a function of local regions with a small interstitial space in ID / OD. The size of the gap can change depending on whether suction pressure is applied via the system. For example, the catheter 200 may also have a slit 236 in the lumen section 222 (shown in Fig. 5B) include, which is configured to expand slightly when suction is applied from an aspiration source, thus improving the seal between the catheter 200 and the guide sheath 400. Additionally or alternatively, the distal tip 406 of the sheath 400 can be designed to move downwards to the outer diameter of the catheter 200 to further enhance the seal. The strength of the resulting localized seal(s) allows for a continuous aspiration lumen from the distal tip of the catheter 200 to a proximal end 403 of the guide sheath 400, where it connects to the aspiration source, even at lower suction forces, with minimal to no leakage.

[0052] Generally, no significant leakage occurs when there is sufficient overlap between the catheter 200 and the guide sheath 400. However, when attempting to reach the distal anatomy, the catheter 200 may be advanced to its limit, resulting in minimal overlap between the catheter 200 and the guide sheath 400. Therefore, an additional seal may be desirable to prevent leakage around the catheter 200 into the guide sheath 400. The seal between the catheter 200 and the guide sheath 400 can prevent this leakage when the catheter 200 is at its maximum extension relative to the sheath 400. distal access catheters

[0053] Again, with reference to the Fig. 2A-2B The distal access system 100 can include one or more catheters 200 configured to extend through and out of the distal end of the guide sheath 400. Depending on the procedure being performed, the catheter 200 can be a distal access, carrier, or aspiration catheter. Fig. Figure 3 illustrates a side view of an implementation of the catheter 200. The catheter 200 may comprise a relatively flexible distal lumen section 222 connected to a stiffer, kink-resistant proximal extension or proximal control element 230. The term "control element" here refers to a proximal region configured to allow a user to perform both a distal push and a proximal pull motion. The control elements described here may also be referred to as spikes, restraint straps, push wires, push tubes, or other elements with a variety of configurations. The proximal control element may be a hollow or tubular element. The proximal control element may also be solid and lack an internal lumen, such as a solid rod, band, or other solid wire-like element.In general, the proximal controls described herein are configured to move their respective component (to which they may be attached or into which they may be integrated) bidirectionally through a lumen.

[0054] The Catheter 200 provides rapid and easy access to stroke sites, even in extremely tortuous cerebral vascular systems. The catheters described herein possess a degree of flexibility and availability that makes them ideally suited to be advanced through the anatomy of the cerebral vascular system without kinking or deformation, even when navigating hairpin bends. For example, the distal lumen segment 222 can perform a 180-degree rotation (see Rotation T in Fig. 1B near the carotid siphon) and maintain the folded width of 4.0 mm without kinking or deformation. Furthermore, the distal lumen section 222 exhibits a degree of flexibility that maintains the natural tortuosity of the vessels through which it is advanced without the application of straightening forces, thus preserving the natural shape and curvature of the anatomy during use. The catheter 200, particularly in combination with a catheter delivery element 300, which is described in more detail below, provides an extended channel over the guide sheath 400, exhibiting exceptional feedability through tortuous anatomy. This allows suction forces to be applied to a target site of the stroke, as well as stroke intervention devices such as another suction catheter or a device like a stent retriever, stent, flow diverter, or other devices.

[0055] A single inner lumen 223 extends through the lumen section 222 between a proximal end and a distal end of the lumen section 222. The inner lumen 223 of the catheter 200 may have a first inner diameter, and the working lumen of the guide sheath 400 may have a second, larger inner diameter. After the catheter 200 is introduced through the working lumen of the sheath 400, the lumen 223 of the catheter 200 may be configured to be fluidically connected to and adjacent with the working lumen of the sheath 400, such that fluid flow into and / or out of the system 100 is possible, for example, by applying suction from a source connected to the system 100 at a proximal end. The combination of sheath 400 and catheter 200 can be in continuous contact with the bloodstream during aspiration at the proximal end by advancing and withdrawing the catheter 200.

[0056] The spiked catheter system can offer advantages over conventional full-length catheters for distal access, particularly with regard to aspiration. The stepwise change in the catheter's inner diameter (i.e., from the catheter's inner lumen of 223 mm to the sheath's working lumen of 400 mm) provides a significant advantage in terms of aspiration flow and force that can be generated by the spiked catheter in combination with the conventional guide catheter. For example, a spiked catheter with an inner diameter of 0.070 mm can be combined with a guide catheter with a standard outer diameter of 6 mm and an inner diameter of 0.088 mm (e.g., Penumbra Neuron MAX 088) to create an aspiration physics where the 0.088-inch catheter diameter predominates, generating a flow of 0.080 mm throughout the system.

[0057] In addition to aspiration procedures, the Catheter 200 and the Distal Access System 100 can be used to deliver tools and interventional instruments. For example, a typical stent retriever delivered via the Catheter 200 may have a long pushwire control element (e.g., 180 cm long). The Distal Access System 100 with a supported Catheter 200 allows access to distal stroke sites with much shorter lengths (e.g., 120 cm–150 cm). The overall length can be as critical as the diameter and radius for aspiration through the catheter. The shorter lengths, combined with the elimination of the multiple RHVs typical of triaxial systems, allow for operation by a single operator.

[0058] When the catheter is described herein as an aspiration catheter, it should not be limited to aspiration alone. Likewise, when the catheter is described herein as a means of delivering a stent retriever or other device, it should not be limited to that purpose. The systems described herein can be used to perform procedures that involve a combination of treatments. For example, Catheter 200 can be used to deliver a stent retriever delivery system, optionally in conjunction with aspiration through Catheter 200. As another example, a user may first perform an initial interventional procedure using the systems described herein, such as an aspiration embolectomy (sometimes called a thrombectomy), and then proceed to another interventional procedure, such as the delivery of a stent retriever or implant.

[0059] The terms “support catheter”, “spinal catheter”, “anchored catheter”, “distal access catheter”, “aspiration catheter” and “intermediate catheter” can be used synonymously herein.

[0060] It is desirable to use a 200 mm catheter with the largest possible inner diameter that can be safely navigated to the site of occlusion to optimize aspiration force in case of aspiration and / or to provide sufficient space for the delivery of a device. A suitable size for the inner diameter of the distal lumen segment 222 may be between 0.040 in and 0.100 in, or preferably between 0.054 in and 0.088 in, depending on the patient's anatomy and the size and composition of the clot. The outer diameter of the distal lumen segment 222 may be dimensioned for navigation into cerebral arteries, for example, at the level of the M1 or M2 segment of the cerebral vessels. The outer diameter (OD) should be as small as possible while maintaining the mechanical integrity of the 200 mm catheter.In one implementation, the difference between the outer diameter of the distal lumen segment 222 of the catheter 200 and the inner diameter of the working lumen of the guide sheath 400 is between 0.001 in and 0.002 in. In another implementation, the difference is between 0.001 in and 0.004 in. The gap between the inner diameter of the guide sheath 400 and the outer diameter of the catheter 200 can vary along the length of the catheter 200. For example, the distal lumen segment 222 of the catheter 200 may have localized areas with an enlarged outer diameter, creating localized areas with a small difference (e.g., approximately 0.001 in) configured for a local seal when suction pressure is applied by the system.

[0061] In some implementations, the distal lumen section 222 of the catheter 200 has a maximum outer diameter (OD) configured to fit through a 6F introducer sheath (0.070 in–0.071 in), and the lumen 223 has an inner diameter (ID) dimensioned to accommodate a 0.054 in catheter. In some implementations, the distal lumen section 222 has a lumen and a distal end with an opening from the lumen, where the lumen at the distal end may have an inner diameter (ID) of at least approximately 0.052 in. In some implementations, the distal lumen section 222 of the catheter 200 has a maximum outer diameter configured to fit through an 8F introducer sleeve (0.088 in), and the lumen 223 has an inner diameter dimensioned to accommodate a 0.070 in or 0.071 in catheter.In some implementations, the maximum outer diameter of the distal lumen section 222 is 2.1 mm, and lumen 223 has an inner diameter of 0.071 inches. In some implementations, lumen 223 has an inner diameter of 0.070 to 0.073 inches. The outer diameter of the guide sheath 400 may be suitable for insertion into at least the carotid artery, with a working lumen of an appropriate size to provide passage for the catheter 200 to treat an occlusion distal to the carotid artery toward the brain. In some implementations, the inner diameter of the working lumen may be approximately 0.074 inches, and the outer diameter of the body of the guide sheath 400 may be approximately 0.090 inches, corresponding to a sheath size of 5 French.In some implementations, the inner diameter of the working lumen may be approximately 0.087 inches and the outer diameter of the guide sheath body 400 approximately 0.104 inches, corresponding to a sheath size of 6 French. In some implementations, the inner diameter of the working lumen may be approximately 0.100 inches and the outer diameter of the guide sheath body 400 approximately 0.117 inches, corresponding to a sheath size of 7 French. In some implementations, the inner diameter of the guide sheath 400 is between 0.087 inches and 0.088 inches, and the outer diameter of the distal lumen segment 222 of the catheter 200 is between 0.082 inches and 0.086 inches, resulting in a diameter difference of between 0.001 inches and 0.005 inches. Smaller or larger tubing sizes are being considered. For example, in some implementations the inner diameter of the lumen 223 is approximately 0.088 inches and the outer diameter of the distal section is between 0.101 inches and 0.102 inches.However, a conventional 7-French sheath has an inner diameter of only about 0.100 inches, and a conventional 8-French sheath has an inner diameter of about 0.113 inches, so they would not provide the appropriate sealing fit with the outer diameter of the distal portion of the catheter for aspiration embolectomy (i.e., a 0.011-inch gap). Therefore, the Guide Sheath 400 can be designed to have an inner diameter better suited to the 0.088-inch catheter, namely between 0.106 inches and 0.107 inches. Additionally, the 0.088-inch catheter can have an increase in outer diameter from 0.101–0.102 inches to about 0.105–0.107 inches near a proximal end region to provide a localized area optimized for sealing with the guide sheath during the application of high pressure.

[0062] In one implementation, the lumen section 222 of the catheter 200 has a uniform diameter from the proximal end to the distal end. In other implementations, the lumen section 222 of the catheter 200 is conical and / or tapers towards the distal end, such that the distal end of the catheter 200 has a smaller outer diameter than a more proximal region of the catheter 200, for example, near the point where the distal lumen section 222 seals with the guide sheath 400. In yet another implementation, the outer diameter of the luminal section 222 of the catheter increases at or near an overlap section to better match the inner diameter of the sheath, as described in more detail below. This increase in outer diameter can be achieved by varying the wall thickness of the catheter 200.For example, the catheter 200 may have a slightly thicker wall near the proximal end to provide a better seal with the sheath than the catheter 200 near the distal end. The catheter 200 can have a thicker wall at this point while maintaining a consistent inner diameter. This implementation is particularly useful in a system with more than one catheter suitable for use with a single access sheath size. In some implementations, a thicker wall can be created by embedding a radiopaque material (e.g., tungsten) so that the local increase in outer diameter can be visualized during a procedure. The catheter 200 may have an increase in outer diameter near the proximal end that is not due to a thicker wall.For example, the inner diameter of the lumen can be increased so that the wall thickness remains uniform, but the lumen size increases, thereby increasing the overall outer diameter at that point.

[0063] The length of the lumen section 222 can be shorter than the length of the working lumen of the guide sleeve 400, so that when the lumen section 222 is advanced towards the target location, an overlap area 348 is created between the lumen section 222 and the working lumen (see Fig. 2B). The length of the overlap section 348 can vary depending on the length of the distal lumen section 222 and the distance to the target relative to the distal end of the guide sheath 400. Taking into account the variation of the occlusion sites and the locations where the distal tip 406 of the guide sheath 400 can be positioned, the dimensions of the lumen section 222 can range from approximately 10 cm to approximately 80 cm, or from 35 cm to approximately 75 cm, or from approximately 45 cm to approximately 60 cm. In some implementations, the distal lumen section 222 of the catheter 200 can be between 45 cm and 70 cm long, and the control element 230 of the catheter 200 can be between approximately 90 cm and approximately 100 cm long. In some implementations, the catheter 200 can have a total working length of approximately 115 cm.In other implementations, the working length of the catheter 200 between a proximal end and a distal end can be greater than 115 cm up to approximately 130 cm. In some implementations, the catheter 200 can have a working length greater than 130 cm between a proximal tab 234 (or a proximal hub) and the distal tip, for example, 133 cm. The distal lumen section 222 can have a shaft length of approximately 40 cm ± 3 cm. The distal lumen section 222 can have a shaft length of at least approximately 45 cm up to a length shorter than the working length of the sheath 400. The body 402 of the guide sheath 400 can be between approximately 80 cm and approximately 90 cm.

[0064] The length of the lumen segment 222 can be less than the length of the body 402 of the guide sheath 400, so that when the catheter 200 is withdrawn from the working lumen, an overlap region 348 remains between the catheter 200 and the inner diameter of the working lumen. A seal can be formed within a region of the overlap region 348. In some implementations, the length of the lumen segment 222 is sufficient to reach a region of the Ml segment of the middle cerebral artery (MCA) and other large vessels from a region of the internal carotid artery, while the proximal end of the lumen segment 222 of the catheter 200 is maintained relative to certain tortuous anatomies (e.g., brachiocephalic take-off BT, aortic arch AA, or within the descending aorta DA).In one implementation, the lumen section 222 of the catheter has a length sufficient to position its distal end within the Ml segment of the MCA and a proximal end within the aortic arch proximal to branches of the arch. In another implementation, the lumen section 222 of the catheter has a length sufficient to position its distal end within the Ml segment of the MCA and its proximal end within the descending aorta DA proximal to the aortic arch AA. In conjunction with a guide sheath 400 with a sheath body 402 and a working lumen, in an implementation where the catheter 200 reaches the ICA, the distance to the embolus can be less than 20 cm.

[0065] The distal lumen segment 222 has a length of less than 80 cm, for example, approximately 45 cm to approximately 70 cm. The distal lumen segment 222 can allow an overlap area 348 with the body 402, in which a seal is formed with the sheath, while still providing sufficient reach to the intracranial vessels. The carotid siphon CS is an S-shaped part of the terminal ICA that begins at the posterior arch of the cavernous ICA and terminates at the ICA bifurcation into the anterior cerebral artery (ACA) and the middle cerebral artery (MCA).In some implementations, the distal lumen section 222 may be between approximately 35 cm and 80 cm, or between 40 cm and 75 cm, or between 45 cm and 60 cm in length, so that the distal end of the catheter 200 can extend at least to the middle cerebral arteries, while the proximal control element 230 and / or the seal at the proximal end of the distal lumen section 222 remains proximal to the carotid siphon and preferably within the aorta, as described in more detail below.

[0066] The distal lumen section 222 can have a length, measured from its attachment point on the proximal control element 230 to its distal end, that is long enough to extend from a region of the internal carotid artery (ICA) proximal to the carotid siphon to a region of the ICA distal to the carotid siphon, including at least the Ml region of the brain. There is an overlap area 348 between the lumen section 222 of the catheter 200 and the working lumen of the guide sheath 400 when the lumen section 222 is inserted into the target anatomy. A seal against injected or aspirated fluid can be achieved within the overlap area 348 where the outer diameter of the catheter 200 along at least one section of the distal lumen section 222 substantially matches the inner diameter of the guide sheath 400, or the difference may be between 0.00 1" and 0.002".The difference between the outer diameter of the catheter and the inner diameter of the guide sheath 400 can vary, for example, between 1 and 2 micrometers, between 1 and 4 micrometers, or between 1 and 12 micrometers. This difference in outer / inner diameter between the sheath and the catheter can extend over the entire length of the distal lumen section 222 or be a difference within a discrete area of ​​the distal lumen section 222, for example, a cylindrical, proximal region of the distal lumen section 222. In some implementations, a seal against the fluid injected or aspirated between the catheter and the sheath can be achieved within the overlap 348 between their essentially similar dimensions without the need to incorporate a separate sealing structure or feature.In some implementations, an additional sealing structure near the proximal end region of the distal lumen section 222 provides a seal between the inner diameter of the sheath and the outer diameter of the catheter.

[0067] The length of the overlap region 348 between the sheath and the distal section varies depending on the distance between the distal end of the sheath and the embolus, as well as on the length of the lumen section 222 between its proximal and distal ends. The overlap region 348 can be dimensioned and configured to create a seal that allows a continuous aspiration lumen from the distal tip region of the catheter 200 to a proximal end region 403 of the guide sheath 400, where it can be connected to an aspiration source. In some implementations, the strength of the resulting seal can be a function of the difference between the outer diameter of the catheter 200 and the inner diameter of the working lumen, as well as the length of the overlap region 348, the applied suction force, and the materials of the components. For example, the seal can be improved by increasing the length of the overlap region 348.However, increasing the length of the overlap region 348 can result in a greater length over which the suction is drawn through the smaller diameter of the lumen section 222 instead of the larger diameter of the working lumen. Another example: Higher suction forces applied by the aspiration source can create a stronger seal between the lumen section 222 and the working lumen, even if the overlap region 348 is shorter. Furthermore, a relatively softer material from which the lumen section and / or body 402 are made can still provide a sufficient seal even when the suction forces are lower and the overlap region 348 is shorter. In one implementation, the gap of the overlap region 348 can provide a seal against a vacuum down to about 28 inHg with minimal to no leakage.The gap in the overlap area can provide a seal against a vacuum of up to approximately 730 mmHg with minimal to no leakage.

[0068] In other implementations, the overlap region 348 itself does not provide a seal between the body 402 and the lumen section 222. Instead, an additional sealing element positioned within the overlap region 348, for example at a discrete location along a region of the lumen section 222, narrows the gap between their respective inner and outer diameters, so that the seal is provided by the sealing element within the overlap region 348. In this implementation, the location of the seal between the lumen section 222 and the body 402 can be positioned more proximal relative to certain convoluted regions of the anatomy. For example, the proximal end region of the lumen section 222 can have a discrete increase in outer diameter that reduces the gap between the outer diameter of the lumen section 222 and the inner diameter of the body 402.This increase in the outer diameter of lumen section 222 can be positioned relative to the overall length of lumen section 222 such that the sealing area between the two components does not have sharp bends. For example, the sealing area can enclose the proximal end of lumen section 222 at a certain distance from the distal tip of the catheter, and this sealing area can be designed to remain within the descending aorta DA when the distal end of lumen section 222 is advanced through the aortic arch into the brachiocephalic trunk BT, the right common carotid artery RCC to the level of the petrosal portion of the internal carotid artery and beyond.Maintaining the sealing area below the level of the aortic arch while the distal end of the catheter is positioned, for example, within the M1 region of the MCA, is a function of the length of lumen segment 222 as well as the length and position of the sealing segment on the catheter. The sealing area on lumen segment 222 can be located at a distance of at least approximately 40 cm, 45 cm, 50 cm, 55 cm, 60 cm, 65 cm, 70 cm, up to approximately 75 cm from the distal tip of the catheter.

[0069] The use of the term "seal" in relation to the catheter and guide sheath refers to a condition in which, when suction is applied, fluid is prevented from passing essentially from one side of the seal to the other. For example, the small gap between the outer diameter of the catheter and the inner diameter of the sheath at the seal can prevent blood from passing between the outer surface of the catheter and the inner surface of the sheath, thus creating a seal. The seal does not necessarily mean that the entire catheter system is sealed. Even if the catheter is "sealed" with the sheath, blood may still be drawn into the lumen of the catheter and through the guide sheath (at least until the distal end of the catheter becomes "blocked," at which point a complete seal of the entire system may occur).

[0070] The catheter 200 can be telescopically displaced relative to the sheath (and / or relative to another catheter 200) so that the distal end of the distal lumen segment 222 can reach cerebrovascular targets, for example, within regions M1 and M2, while the proximal end of the distal lumen segment 222 remains proximal to or below the level of sharp bends along the insertion path. For example, the catheter system entry point may be in the femoral artery, and the target embolus may be distal to the right carotid artery (RCC), such as within the M1 segment of the middle cerebral artery on the right side. The proximal end of the distal lumen segment 222 (e.g.,(where the sealing element is located and / or where the material transitions to the proximal control element 230) can remain within a vessel that lies proximal to a highly tortuous anatomy: the carotid siphon, the right carotid artery (RCC), the brachiocephalic trunk (BT), the origin of the brachiocephalic artery from the aortic arch, the aortic arch (AA) where it transitions from the descending aorta (DA) to the ascending aorta. The descending aorta (DA) is a continuously straight segment in most anatomies. FIG. IC illustrates the aortic arch (AA) separating the ascending aorta (AscA) and the descending aorta (DA). The most distal carotid artery from a femoral access point is the right carotid artery (RCC), which branches off from the brachiocephalic trunk (BT) (or the left carotid artery (LCC), which in some patients branches off from the same brachiocephalic trunk (BT) - the so-called "bovine anatomy").The distal portion of lumen 222 can be configured to extend, upon insertion into the RCC, from a target site in regions M1 or M2 to the brachiocephalic trunk (BT), to the level of the aortic arch (AA), or to the descending aorta (DA), sometimes referred to here as "below the branch" of the brachiocephalic trunk (BT). This avoids requiring the stiffer proximal control element 230, or the transition of material between the stiffer proximal control element 230 and the distal portion of lumen 222, to navigate the often very sharp bend of the aortic arch or the bend of the brachiocephalic branch. The bend of the aortic arch and the branch of the brachiocephalic trunk are frequently the first sharp bends that catheters must navigate as they ascend to the brain via the RCC artery.The less flexible sections of the catheter segment can bypass the areas of increased tortuosity near the internal carotid artery. The distal lumen section 222 can change its flexibility towards the proximal region to approximate the flexibility of the stiffer proximal control element 230. The distal end of the catheter can be used to target left cerebral blood flow, while the proximal control element 230 of the catheter 200, as well as the material transitions of the distal lumen section 222, remain near the proximal control element 230 below the turn of the brachiocephalic branch (e.g., within the aorta, proximal to the origin of the left carotid artery (LCC), and preferably within the descending aorta (DA). Similarly, the area of ​​the seal, or a large part of the area of ​​the seal, remains between the distal lumen section 222 and the shell, preferably proximal to these strong coils.

[0071] In some implementations, the distal lumen segment 222 may have a length that allows the distal end of the distal lumen segment 222 to extend distal to the carotid siphon into the cerebral portion of the internal carotid artery, while at the same time the proximal end of the distal lumen segment 222 (e.g., where it transitions into the proximal control element 230, as described in more detail below) remains within the aorta proximal to the origin of the brachiocephalic trunk BT, for example, within the descending aorta DA (see Fig. 2C). In this implementation, the distal lumen segment can have a length between approximately 35 cm and 75 cm, for example between 45 cm and 70 cm or 65 cm.

[0072] The attachment area between the stiffer proximal control element 230 and the more flexible distal lumen segment 222 changes material and flexibility. This change can lead to kinking. Therefore, it is preferable to avoid forward movement of the attachment area into extreme bends. For example, the distal lumen segment 222 may be long enough to allow the attachment point to be advanced no further than the first turn of the carotid siphon, no further than the origin of the brachiocephalic artery 610, no further than the aortic arch AA, or no further than the descending aorta DA when the catheter is advanced from a femoral access site. In some implementations, the distal lumen segment 222 is long enough to keep the attachment point within the descending aorta DA while still providing access to the M1 or M2 regions of the neurovascular bundle.The point of material change within the outermost bend of the brachiocephalic branch BT from the aortic arch AA is generally avoided if the distal lumen segment 222 has a length between approximately 35 cm and approximately 75 cm or 45 cm and 70 cm or 65 cm.

[0073] A seal can be fabricated on and / or within the overlap region 348 between the distal lumen segment 222 and the sheath body 402. Generally, it may be desirable to position the seal between the distal lumen segment 222 and the sheath body 402 outside of extreme bends in the neurovascular region. In some implementations, the distal lumen segment 222 may have a length that allows its distal end to extend distal to the carotid siphon into the cerebral portion of the internal carotid artery, while simultaneously keeping the region containing the seal and the sheath body 402 proximal to the brachiocephalic origin BT, the aortic arch AA, or within the descending aorta DA. In this implementation, the length can range from approximately 35 cm to approximately 75 cm, from approximately 40 cm to approximately 65 cm, or greater than 40 cm down to a length that is less than the working length of the encapsulation body 402.

[0074] With regard to Fig. 2C The unreinforced region 407 of the distal tip 406 of the sheath 400 can have a length that allows it to provide sufficient sealing force against the outer surface of the catheter 200 when a vacuum is applied. The distal lumen section 222 of the catheter 200, used with this implementation of the sheath 400, can have a length that is less than 60 cm, less than 50 cm, less than 40 cm, less than 35 cm, less than 30 cm, down to about 10 cm. For example, the distal lumen section 222 of the catheter 200, when used with a sheath 400 that has an unreinforced region 407 configured to seal against the outer diameter of the catheter 200, can be less than about 30 cm, for example, between about 10 cm and about 30 cm.

[0075] The seal within the overlap region 348 may be due to the small difference between the inner and outer diameters. The proximal end region of the distal lumen section 222 may have an increase in the outer diameter (e.g., increased wall thickness), creating a region of local sealing against the inner diameter of the guide sleeve. Additionally or alternatively, the localized seal may be due to an additional sealing element positioned on an outer surface of the distal lumen section or an inner surface of the sleeve body. A sealing element may include an increased diameter or a protruding feature in the overlap region. The sealing element may include one or more external rib structures. The one or more rib structures may be compressible when the lumen section is inserted into the lumen of the sleeve body.The rib geometry can be designed such that the sealing element acts like an O-ring, a square ring, or another piston seal. The sealing element can include one or more inclined surfaces that are pre-tensioned against an inner surface of the sheath lumen. The sealing element can include one or more expandable elements that are actuated to create a seal. The inflatable or expandable element can be a balloon or a sheathed braided structure that can be inflated or expanded and provides a seal between the two devices at any time, even after the catheter has been positioned at the desired location. Thus, no sealing force needs to be applied to the catheter during positioning; it is only applied or actuated to create a seal after the catheter has been positioned.The sealing element can be positioned on the outer surface of the distal lumen segment, for example, near the proximal end of the distal lumen segment, and can be located within the overlap area. More than one sealing element can be positioned along the length of the catheter.

[0076] The additional sealing element of the distal lumen section 222 can be a cup seal, a balloon seal, or a disc seal formed from a soft polymer and positioned around the outside of the distal lumen section near the overlap area to provide an additional seal. The sealing element can be a thin-walled tube with an outer diameter substantially equal to the inner diameter of the lumen of the casing body. The tube can be sealed at one end to form a cup seal or at both ends to form a disc or balloon seal. The balloon seal can enclose trapped air, forming a collapsible space. One or more slits can be formed through the wall of the tube such that the balloon seal is collapsible and can more easily pass through a radiofrequency penetrator (RFP).The balloon seal does not need to include slits to create a less collapsible sealing element that retains the trapped air. The sealing element can be adjusted to fit the cover and achieve the desired degree of collapse.

[0077] In some implementations, the system may include one or more features that limit the extension of the catheter 200 relative to the sheath 400 to a specific distance, so that the achieved overlap area 348 is optimal and / or over-advancement of the catheter 200 is prevented. For example, a tab on a region of the catheter 200 may be positioned such that, when the catheter 200 is advanced through the sheath 400 by a selected distance, it is sized to rest against the port through which the catheter 200 is inserted, thus preventing further distal extension of the catheter 200 through the sheath 400.A tab can also be positioned on a region of the catheter advancement element 300 to ensure optimal extension of the catheter advancement element 300 relative to the distal end of the catheter 200, thus supporting the advancement of the catheter 200 into the intracranial vessels.

[0078] Again, in relation to Fig. 3 The proximal control element 230 is configured to move the distal lumen segment 222 bidirectionally through the working lumen of the guide sheath 400, such that the distal lumen segment 222 can be advanced out of the guide sheath 400 into a target position for treatment within the target vessel. In some implementations and as in Fig. As shown in Figure 3, the proximal control element 230 of the catheter 200 can have a smaller outer diameter than the outer diameter of the distal lumen section 222, thereby forming a proximal spine or attachment to the catheter 200. A smaller outer diameter for the proximal control element 230 than the outer diameter of the distal lumen section 222 allows the larger-diameter working lumen of the sheath 400 to maintain greater suction forces than would otherwise be possible through the smaller-diameter lumen section 222 of the catheter 200, or allows the insertion of working devices through the lumen with lower frictional forces.The significantly shorter length of lumen segment 222 results in an increase in the lumen diameter between lumen segment 222 adjacent to the working lumen, thus providing a significantly larger radius and lumen area for advancing a working device and / or aspirating the clot, particularly compared to other systems where the aspiration lumen extends along the entire inner diameter of the aspiration catheter. Specifically, the combined volume of the catheter 200 lumen area and the working lumen area proximal to the distal lumen segment 222 is larger than the lumen area of ​​the large-diameter catheter along the entire length of the system. This increases the likelihood of embolus removal during a single aspiration attempt.In particular, the graduated lumen diameter along the proximal control element 230 can enable greater aspiration force, resulting in improved aspiration of the embolus.

[0079] Furthermore, this configuration of the catheter 200 and the proximal control element 230 significantly reduces the time required to advance and re-advance the catheter 200 and / or working devices through the working lumen from the distal opening 408. The proximal control element 230 of the catheter 200 has a length and structure that extends through the working lumen of the guide sleeve 400 to a proximal end of the system 100, allowing the proximal control element 230 to be used for advancing and re-advancing the catheter 200 through the working lumen. However, the proximal control element 230 of the catheter 200 occupies only a fraction of the lumen space of the system 100, resulting in an increased lumen area for aspiration and / or delivery of working devices.The increased lumen diameter also increases the annular area available for forward flushing of contrast medium, saline, or other solutions, while devices such as microcatheters or other instruments can be positioned coaxially within the lumen section 222 of the catheter 200 and / or within the working lumen. This can enhance the ease and capability of performing angiograms during instrument navigation.

[0080] In one implementation, the distal lumen segment 222 of the catheter 200 is designed to be flexible and lubricated to ensure safe navigation to the target site. The distal lumen segment 222 can be kink-resistant and collapse-resistant when subjected to high suction forces to effectively aspirate a clot. The lumen segment 222 may exhibit increasing flexibility towards the distal end, with uniform material changes along its length to prevent kinks, angles, or sharp bends in its structure, for example, during navigation through sharp angles such as those with 90° or more up to 180° bends, for example at the aortoiliac junction, the origin of the left subclavian artery LSA from the aorta AA, the origin of the brachiocephalic artery (innominate artery) BT from the ascending aorta AscA, and many other peripheral locations, such as the carotid siphon.The distal lumen section 222 can change from a lower flexibility near its connection with the proximal control element 230 to a higher flexibility at the most distal end.For example, a first section of the distal lumen segment 222 can be formed from a material with a material hardness of 72D along a first length, a second section can be formed from a material with a material hardness of 55D along a second length, a third section can be formed from a material such as Pebax or MX1205 with a material hardness of 40D along a third length, a fourth section can be formed from a material with a material hardness of 35D along a fourth length, a fifth section can be formed from a material with a material hardness of 25D along a fifth length, a sixth section can be formed from a material such as Tecoflex with a material hardness of 85A along a sixth length, and a final distal section of the catheter can be formed from a material such as Tecoflex with a material hardness of 80A.In some implementations, the distal end of the distal lumen section 222 of the catheter 200 may be made of a material such as Tecothane with a material hardness of 62A. Thus, the distal lumen section 222 changes its flexibility from lower near its junction with the proximal control element 230 to higher at the most distal end, where, for example, a distal tip of the catheter advance element 300 may extend from the distal end of the catheter 200. Other procedural catheters described herein may have a similar design, providing variable relative stiffness that changes from the proximal end to the distal end of the catheter, as described elsewhere herein. The change in flexibility from the proximal to the distal end of the distal lumen section 222 can be achieved by a variety of methods.

[0081] The distal lumen section 222 can include two or more layers. In some implementations, the distal lumen section 222 includes an inner sliding lining, a reinforcing layer, and an outer mantle layer, each of which will be described in more detail.

[0082] The sliding inner lining can be a PTFE lining with one or more thicknesses along variable flexibility sections. The PTFE lining can be a tubular lining formed by dip coating or film casting of a removable mandrel, such as a silver-plated copper wire, as known in engineering. Various layers of different thicknesses can be applied. For example, a base layer of etched PTFE approximately 0.005 inches thick can be formed. A second, middle layer of Tecoflex SG-80A approximately 0.0004 inches thick can be formed over the base layer. A third, top layer of Tecoflex SG-93A approximately 0.0001 inches thick or less can be formed over the middle layer.A reinforcing layer and / or reinforcing fiber can be applied to the inner lining, followed by the outer mantle layer and / or an additional outer coating, before the mandrel is removed by longitudinal stretching.

[0083] The reinforcing layer is a generally tubular structure formed, for example, from a wound tape, coil, or braid. The material for the reinforcing structure can be stainless steel, such as 304 stainless steel, nitinol, a cobalt-chromium alloy, or another metal alloy that provides the desired combination of strength, flexibility, and compressive strength. In some implementations, the distal lumen section 222 has a reinforcing structure consisting of a nitinol tape wound into a coil. The coil reinforcement can be, for example, a tapered nitinol tape fixed to a specific inner diameter (e.g., 0.078 in to 0.085 in) and having a pitch (e.g., between 0.012 in and 0.016 in). The tape can be made of 304 stainless steel (e.g., approximately 0.012 in x 0.020 in).The coil can be thermofixed before being transferred to the catheter. The coil pitch can increase from the proximal end to the distal end of the distal lumen section 222. For example, the tape coils may have gaps, and the size of these gaps can increase toward the distal end of the distal lumen section 222. For example, the gap between the tape coils near the proximal end of the distal lumen section 222 may be approximately 0.016 inches, while the gap between the tape coils near the distal end may be larger, such as 0.036 inches. This change in pitch provides increased flexibility near the most distal end of the distal lumen section 222. The distal lumen section 222 may additionally contain one or more reinforcing fibers (see figure). Fig. 8B-8C) are included, configured to prevent coil elongation as described in more detail below. The reinforcement structure may incorporate multiple materials and / or designs to vary the flexibility along the length of the distal lumen section 222.

[0084] The outer sheath layer can consist of discrete polymer sections with different degrees of hardness, compositions and / or thicknesses to vary the flexibility along the length of the distal lumen section 222.

[0085] At least one section of the outer surface of the catheter 200 may be provided with a lubricating coating, such as a hydrophilic coating. In some implementations, the coating may be applied to an inner and / or outer surface to reduce friction during guidance. The coating may include a variety of materials known in the art. The proximal control element 230 may also be coated to improve guidance through the working lumen. Suitable lubricating polymers are well known in the art and may include silicone and the like, hydrophilic polymers such as high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxides, polyvinylpyrrolidone, polyvinyl alcohols, hydroxyalkylcellulose, alginates, saccharides, caprolactone, HYDAK coatings (e.g., B-23K, HydroSleek), and the like, as well as mixtures and combinations thereof.Hydrophilic polymers can be mixed with each other or with formulations of water-insoluble compounds (including some polymers) to obtain coatings with suitable lubricity, adhesion and solubility.

[0086] In some implementations, the distal lumen section 222 includes two or more layers. In some implementations, the distal lumen section 222 includes an inner sliding lining, a reinforcing layer, and an outer sheath layer. The outer sheath layer may consist of discrete sections of polymer with varying degrees of hardness, compositions, and / or thicknesses to vary the flexibility along the length of the distal lumen section 222. In one implementation, the sliding inner lining is a PTFE lining with one or more thicknesses along variable sections of flexibility. In one implementation, the reinforcing layer is a generally tubular structure formed, for example, from a wound tape or wire coil or a braid.The material for the reinforcement structure can be stainless steel, for example, stainless steel 304, nitinol, a cobalt-chromium alloy, or another metal alloy that provides the desired combination of strength, flexibility, and compressive strength. In one implementation, the reinforcement structure incorporates multiple materials and / or designs to vary the flexibility along the length of the distal lumen segment 222. In one implementation, the outer surface of the catheter 200 is provided with a lubricating coating, for example, a hydrophilic coating. The proximal control element 230 can also be coated to improve guidance through the working lumen.Suitable lubricating polymers are known in the industry and can include silicone and the like, hydrophilic polymers such as high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxides, polyvinylpyrrolidone, polyvinyl alcohols, hydroxyalkylcellulose, alginates, saccharides, caprolactone and the like, as well as mixtures and combinations thereof.

[0087] Again, in relation to the Fig. 2A-2B The distal lumen segment 222 of the catheter 200 may have a variety of radiopaque markers. A first radiopaque marker 224a may be located near the distal tip area to aid navigation and correct tip positioning under fluoroscopy.

[0088] Additionally, a proximal region of the catheter 200 may feature one or more proximal radiopaque markers 224b, such that the overlap region 348 can be visualized as the relationship between a radiopaque marker 411 on the guide sheath 400 and the radiopaque marker 224b on the catheter 200. The proximal region of the catheter 200 may also feature one or more radiopaque markers that, for example, visualize the proximal opening into the single lumen of the catheter, as described in more detail below. In one implementation, the two radiopaque markers (marker 224a at the distal tip and a proximal marker 224b) are distinct to minimize confusion in the fluoroscopic image.For example, the proximal marker 224b of the catheter may be a single band, and the marker 411 on the guide sheath 400 may be a double band. All markers on a device placed through the distal access system may also feature another type of band or marker. The radiopaque markers 224 of the distal lumen segment 222, particularly those near the distal tip region navigated through extremely tortuous anatomy, may be relatively flexible such that they do not impair the overall flexibility of the distal lumen segment 222 near the distal tip region. The radiopaque markers 224 may be tungsten- or platinum-coated markers, which are relatively flexible compared to other types of radiopaque markers used in devices where flexibility is not a primary concern.In some implementations, the X-ray dense marking may consist of a band of tungsten-coated PEBAX with a hardness of 35D.

[0089] How best to in the Fig. As shown in Figures 8B-8C, at least one reinforcing fiber 801 can be integrated into a wall of the distal lumen section 222 to prevent stretching of a wound reinforcing layer 803. The fiber 801 can be positioned between the lining layer 805 and the reinforcing layer 803. The fiber 801 can extend along the longitudinal axis A of the catheter 200 from a proximal end region of the distal lumen section 222 to a distal end region of the lumen section 222. The proximal end of the fiber 801 can be connected to a region of the distal lumen section 222 near the point where it connects to the proximal control element 230. A distal end of the fiber 801 can terminate near the distal end of the distal lumen section 222. The distal end of fiber 801 can be detected between the distal marker band 224a and one end of the reinforcement layer 803.The distal marker band 224a can be completely encapsulated between the inner lining 805 and the outer sheath 807. In some implementations, the distal end of fiber 801 extends distally to the last coil of the reinforcing layer 803, which runs beneath marker band 224a, and then loops back around band 224a in a proximal direction. The free end of fiber 801 is thereby captured beneath the reinforcing layer 803 and marker band 224a. The reinforcing fiber 801 thus terminates at the point where the reinforcing layer 803 ends, leaving an approximately 10 cm to 12 cm long unreinforced distal tip region. The catheter 200 can include several reinforcing fibers 801 extending longitudinally along the distal lumen section 222, such as two, three, four or more fibers 801 distributed around the circumference of the lumen section 222 and aligned parallel to each other and to the longitudinal axis A of the catheter 200.The reinforcing fiber 801 may also terminate at a location further distal or proximal than the location of the distal end marker 224a. The material of the reinforcing fiber 801 may vary, including but not limited to various high-strength polymers such as polyester, PEEK, and other similar materials.

[0090] The distal lumen section 222 of the catheter 200 can have a proximal control element 230 that is connected to the single lumen of the distal lumen section 222 near a proximal opening. The distal lumen section 222 and the proximal control element 230 can be connected to each other by a coupling band 901 (see Fig. 9A-9C) are connected to each other. A proximal end 905 of the coupling band 901 can be attached to a distal end of the proximal control element 230, and a distal end of the coupling band 901 can be attached to the distal lumen section 222. The proximal end 905 of the coupling band 901 can include a slot 907 configured to weld to the proximal control element 230 of the catheter 200. The catheter 200 can include a strain relief along a skive length, such as made of tungsten-containing PEBAX. The distal end of the coupling band 901 can be cut to form a plurality of coils 903. These spirals 903 are configured to blend with the coils of the reinforcement layer 803 in the proximal end region of the distal lumen section 222.The size of the gap between the spirals 903 of the coupling tape 901 can be substantially the same as the size of the gap between the coils of the reinforcing layer 803, such that they can blend cleanly without creating localized areas of increased wall thickness due to overlaps. The thickness of the spirals 903 can be, but need not be, similar to the thickness of the tape forming the reinforcing layer 803. For example, the wound reinforcing layer 803 can be formed from a nitinol tape approximately 0.003 inches thick. The coupling tape 901 can have a wall thickness of approximately 0.003 inches, such that the spirals 903 and the coils of the reinforcing layer 803 can have a similar material thickness.This similarity in material thickness between the turns and the spirals 903 contributes to a generally uniform outer profile, which can be minimized and avoids the formation of a significantly increased wall thickness in this region of the coupling. A flat proximal end of the distal lumen section 222 helps to maximize the inner diameter while keeping the outer diameter as small as possible, for example, by reducing the inner diameter of the guide sheath to a minimum (e.g., below about 0.113 in or about 0.107 in). The connecting band 901 can enclose an opening 911 through the central region 909, configured to receive a proximal end of the reinforcing fiber 801, which extends longitudinally through the distal lumen section 222.The region of overlap between the distal end of the proximal control element and the distal lumen segment 222 can vary, but can be at least approximately 5 mm, at least approximately 7 mm, or at least approximately 10 mm to ensure a uniform and smooth transition. The overlap between the proximal control element and the distal lumen segment 222 can be approximately 5 mm to approximately 15 mm.

[0091] As previously mentioned, the distal end of the proximal control element 230 can be welded to the proximal end 905 of the coupling band 901. In some implementations, the distal end region of the proximal control element 230 is chamfered in some places and flat in others. The proximal control element 230 can be a stainless steel band (e.g., 0.012 in x 0.020 in or 0.014 in x 0.020 in along most of its length). A distal end region of the proximal control element 230 may have an interrupted taper, allowing the thickness of the band to change from a thickness of 0.012 in or 0.014 in to a thickness that is equal to or not substantially different from the thickness of the spirals 903 on the coupling band 901, which is attached to a proximal end region of the distal lumen section 222.The discontinuous taper can include a flat length that is bounded at the proximal and distal ends by a tapered length. The flat length allows for a more uniform, minimal material thickness between the distal lumen section 222 and the proximal control element 230, thus avoiding weak points that are more prone to kinking. For example, the distal end region of the proximal control element 230 can have a first tapered length that changes its thickness from 0.012 in to 0.008 in, and a second tapered length that changes its thickness from the thickness of the flat length to approximately 0.003 in. In other implementations, the distal end region of the proximal control element 230 may have a first conical length that changes its thickness from 0.014 in to a thickness of 0.010 in, and a second conical length that changes its thickness from the thickness of the flat length to about 0.003 in.The spirals 903 of the coupling band 901 can have a thickness corresponding to the end thickness of the proximal control element 230. The lengths of the tapered and flat sections can vary. In some implementations, the first tapered length can be approximately 0.12 cm, the flat length approximately 0.2 cm, and the second tapered length approximately 0.15 cm. Uniform thickness along this flat length is a useful goal for catheter fabrication. The catheter need not have a proximal control element 230 in the form of a band and can have any of the configurations described herein.

[0092] As previously mentioned, the proximal control element 230 is configured to allow distal advancement and proximal insertion of the catheter 200 through the working lumen of the guide sheath 400, including passage out of the distal opening 408. In one implementation, the length of the proximal control element 230 is longer than the total length of the guide sheath 400 (from the distal tip to the proximal valve), by approximately 5 cm to 15 cm. The length of the body 402 can range from 80 to 90 cm, or up to approximately 100 cm or up to approximately 105 cm, and the length of the proximal control element 230 can range from 90 to 100 cm.

[0093] Referring to Fig. 3. The proximal control element 230 may include one or more markings 232 to indicate the overlap between the distal lumen section 222 of the catheter 200 and the sheath body 402, as well as the overlap between the distal lumen section 222 of the catheter 200 and other interventional devices that may extend through the distal lumen section 222. At least one initial marking 232a may be an RHV proximity marking positioned such that, when the marking 232a is aligned with the proximal hemostasis valve 434 of the sheath during the insertion of the catheter 200 through the guide sheath 400, the catheter 200 is positioned at its most distal position with the minimum overlap length required to create a seal between the catheter 200 and the working lumen.At least one second marker 232b can be a fluoro-saver marker that can be positioned on the control element 230 and is located at a distance from the distal tip of the distal lumen section 222. In some implementations, a marker 232 can be positioned approximately 100 cm from the distal tip of the distal lumen section 222.

[0094] The proximal control element 230 can include a gripping function, such as a tab 234, at its proximal end to allow the proximal control element 230 to be easily grasped and advanced or retracted. The tab 234 can be connected to one or more other components of the system, as described in more detail below. The proximal tab 234 can be designed to be easily identifiable among all other devices that can be inserted into the proximal sleeve flap 434, such as guide wires or reusable stent connector wires. A section of the proximal control element 230 and / or the tab 234 can be colored or marked with a bright color to easily distinguish it from guide wires, reusable stent connectors, or the like.When multiple catheters 200 are used together in a nested arrangement to reach more distal locations in the brain, each proximal control element 230 and / or each tab 234 can be color-coded or otherwise labeled to clearly indicate to an operator which catheter 200 is connected to which proximal control element 230. The proximal section 366 of the catheter delivery element 300 can also include a color to distinguish it from the proximal control element 230 of the catheter 200.

[0095] The tab 234 can be integrated into, or be present in addition to, a proximal hub connected to a proximal end of the control element 230. As described in more detail below, the proximal control element 230 can, for example, comprise a hypotube with a lumen. The lumen of the hypotube can be located at a proximal end of the control element 230 for fluid exchange with the proximal hub, such that suction forces and / or fluids can be delivered through the hypotube via the proximal hub. The proximal control element 230 can also be a solid element and need not include a lumen to transmit suction forces to the distal end of the catheter 200.

[0096] The proximal control element 230 can be configured with sufficient rigidity to allow advancement and retraction of the distal lumen segment 222 of the catheter 200, yet still be flexible enough to navigate the cerebral anatomy without kinking, if necessary. The configuration of the proximal control element 230 can vary. In some implementations, the proximal control element 230 may have a tubular element with an outer diameter that is essentially identical to the outer diameter of the distal lumen segment 222, similar to a typical catheter device. In other implementations, the outer diameter of the proximal control element 230 is dimensioned so that it does not occupy too much lumen area within the lumen of the guide sheath 400, thereby creating an enlargement of the inner diameter for aspiration.

[0097] The proximal control element 230 can be a solid metal wire having a round, rectangular, trapezoidal, D-shaped or oval form (see Fig. 4A-4G). The proximal control element 230 can have a flattened wire strip with a rectangular shape, as in Fig. 4A shown. The flattened wire strip may also have a square, rectangular, or other shape. The wire strip may be bent along an arc into a circular, oval, C-shaped, or quarter-circle shape, or any other form. Thus, an inward-facing surface of the strip may be essentially flat, and an outward-facing surface of the strip (i.e., the surface configured to abut an inner diameter of the access sheath through which it extends) may be essentially curved (see Fig. 4F-4G). The curvature of the surface can essentially match the curvature of the inner surface of the access sheath. The resulting shape of the band can generally be trapezoidal. The overall dimensions of the band can vary depending on its shape and the size of the distal lumen segment. The 0.054-inch catheter 200 can have a proximal control element 230 that is trapezoidal or D-shaped in cross-section. The inward-facing, flat surface can be approximately 0.020 inches wide, and in the case of the trapezoidal implementation, the outward-facing, curved surface can extend along an arc approximately 0.030 inches long.The 0.070-inch Catheter 200 can have a proximal extension with a trapezoidal or D-shaped cross-section. The width of the inward-facing flat surface is slightly larger, for example, approximately 0.025 inches. In the case of the trapezoidal implementation, the outward-facing curved surface can extend along an arc approximately 0.040 inches long. The 0.088-inch Catheter 200 can have a proximal extension with a trapezoidal or D-shaped cross-section. The width of the inward-facing flat surface is approximately 0.035 inches, and the outward-facing curved surface of the trapezoidal implementation can extend along an arc approximately 0.050 inches long.

[0098] The proximal control element 230 can be a hollow tube with a continuous lumen 235, for example a hypotube, as in Fig. Figure 4B shows that the hypotube can have an oval or circular shape. In one implementation, the proximal control element 230 is a stainless steel strip with dimensions of approximately 0.012 in x 0.020 in. In another implementation, the proximal control element 230 is a stainless steel strip with dimensions of approximately 0.014 in x 0.020 in. In yet another implementation, the proximal control element 230 is a round wire with dimensions of 0.014 in to 0.018 in. In yet another implementation, the proximal control element 230 is a strip with thicknesses of 0.010 in to 0.015 in and 0.015 in to 0.025 in. In yet another implementation, the proximal control element 230 is a hypotube formed from a flattened strip of rigid material having a tubular shape and a lumen 235.In some implementations, the proximal control element 230 can be formed from a flattened strip of stainless steel and rolled into a hypotube such that the proximal control element 230 has a wall thickness of about 0.007 in, an inner diameter of about 0.004 in, and an outer diameter of about 0.018 in before the hypotube is modified into an oval shape. The ovalized hypotube can maintain an inner diameter of at least 0.001 in along at least one first dimension and an outer diameter of at least 0.015 in along at least one first dimension. In one implementation, the material of the proximal control element 230 is a metal such as stainless steel or nitinol, or a plastic such as one made from a variety of polymers.

[0099] In one implementation, the proximal control element 230 is a stainless steel hypotube with an oval shape (see Fig. 4B). The oval shape can increase the column strength, shear force, and buckling resistance of the proximal control element 230 to improve advancement through tortuous anatomy. The cross-sectional area of ​​an oval hypotube minimizes the influence of the catheter 200 on the movement of other instruments through the working lumen of the sheath 400. Fig. Figure 4C illustrates a cross-sectional view of the working lumen of the shell 400, which has a proximal control element 230 extending through it. The proximal control element 230 has a rectangular shape. Fig. Figure 4D illustrates a cross-sectional view of the working lumen with an oval hypotube proximal control element 230 and a catheter delivery element 300 extending through it. Fig. Figure 4E illustrates the surface area comparison between the rectangular band and the oval hypotube. The oval hypotube has a smaller surface area compared to the rectangular band, which allows for a higher flow rate through the working lumen, for example, during the application of suction forces. The materials, dimensions, and shape of the proximal control element 230 can be selected based on the materials, dimensions, and shape of the distal lumen section 222. For example, the proximal control element 230 can be a rectangular band made of 340 stainless steel with dimensions of 0.012 in x 0.020 in, and the distal lumen section 222 can have an inner diameter of approximately 0.054 in to approximately 0.072 in.In another implementation, the proximal control element 230 can be a rectangular stainless steel 340 band with dimensions of 0.014 in x 0.020 in, and the distal lumen section 222 can have an inner diameter of approximately 0.088 in. The added weight of the stainless steel band 230 can be useful for advancing a catheter with a larger inner diameter without kinking.

[0100] With regard to the Fig. In 5A-5F, the junction between the distal lumen section 222 of the catheter 200 and the proximal control element 230 can be configured to allow a smooth transition in flexibility between the two sections, thus avoiding kinks or weak points. The smooth transition at the junction between the distal lumen section 222 and the proximal control element 230 also allows for smooth passage of devices through the continuous inner lumen formed by the working lumen of the guide sheath 400 and the lumen 223 of the lumen section 222 of the catheter 200. In one implementation, the distal lumen section 222 has a transition section 226 near the proximal opening into the single lumen, where the lumen section 222 connects to the proximal control element 230 (see Fig. 5A). The transition section 226 may have an angled cut such that there is no abrupt step transition from the working lumen of the guide sheath 400 to the inner lumen 223 of the catheter 200. The angled cut may generally be planar. In an alternative implementation, the angled cut is curved or stepped to create a more gradual transition zone. The proximal end of the distal lumen section 222 may be obliquely angled relative to the longitudinal axis of the catheter 200 such that the proximal end and the proximal opening into the lumen are at an angle greater than 90° to the longitudinal axis of the catheter 200, for example, between approximately 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, or 45° to less than 90°.The proximal end of the distal lumen section 222 can also be oriented substantially perpendicular to the longitudinal axis of the catheter 200, such that the proximal end and the proximal opening into the lumen form an angle of substantially 90° to the longitudinal axis of the catheter 200. Similarly, the distal end of the distal lumen section 222 can be angled obliquely relative to a longitudinal axis of the catheter 200, such that the distal end and the distal opening from the lumen 223 are positioned at an angle other than 90° to the longitudinal axis of the catheter 200, for example, between approximately 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, or 45° below 90°. The distal end region of the distal lumen section 222 can also be oriented essentially perpendicular to the longitudinal axis of the catheter 200, so that the distal end and the distal opening into the lumen form an angle of essentially 90° to the longitudinal axis of the catheter 200.

[0101] The proximal control element 230 can be connected to a proximal end region of the catheter 200 and / or extend along at least one portion of the distal lumen section 222, such that the proximal control element 230 is connected to the distal lumen section 222 at a distance from the proximal end that defines the proximal opening into the lumen, for example, via the connecting band 901. The proximal control element 230 can be connected to the distal lumen section 222 by a variety of mechanisms, including gluing, welding, bonding, sandwiching, stringing, fastening, or tying one or more components of the proximal control element 230 and / or the lumen section 222. The distal lumen section 222 and the proximal control element 230 can be connected by a weld, a mechanical connection, an adhesive connection, or a combination thereof.In some implementations, the proximal control element 230 and the lumen section 222 are connected by sandwiching the proximal control element 230 between layers of the distal lumen section 222. For example, the proximal control element 230 may have a hypotube or a rod whose distal end is beveled, ground, or cut so that the distal end can be attached to the layers of the catheter section 222 near a proximal end region using composite material or otherwise. The bevel length of the proximal control element 230 may be approximately 7 mm and may include a tungsten-loaded Pebax strain relief along its length. The overlap area between the distal end of the proximal control element 230 and the lumen section 222 may be at least approximately 1 cm.This type of coupling enables a smooth and uniform transition from the proximal control element 230 to the lumen section 222.

[0102] Furthermore, with regard to the Fig. 5A-5F, the transition section 226 of the distal lumen section 222 can open to form a proximal tail 238, which extends a length proximal to the transition section 226. In some implementations, the proximal tail 238 has a cross-sectional geometry that is essentially curved. For example, the proximal tail 238 can extend along an arc of the longitudinal axis of the catheter 200 between approximately 20 and approximately 90 degrees. In some implementations, the proximal tail 238 is curved to create a funnel shape and facilitates the loading and reloading of a catheter delivery element 300 into the lumen of the catheter 200. In other implementations, the edges of the proximal end piece 238 are curved such that the proximal end piece 238 is not essentially flat.The curved shape can vary, including a teardrop shape, which allows for a smooth transition and improved loading / reloading of the catheter delivery element 300 into the lumen and avoids flat edges that could rub against and become entangled in the component during insertion. In other implementations, the proximal end 238 is essentially flat. The proximal end 238 can provide a smooth transition between the distal lumen segment 222 and the proximal control element 230 when the device is forced to bend. This can reduce the likelihood of kinking and facilitate pushing against resistance.

[0103] The dimensions of the proximal end piece 238 may vary. The dimensions in the Fig. The proximal end piece 238 shown in Figures 5A-5F is relatively wide compared to the width of the proximal control element 230 and can therefore be longer without impairing the ability of other devices to be inserted through the proximal opening into the lumen at the transition region 226. In other implementations, the proximal tail 238, defined by a region not supported by the coils of the reinforcing layer 803 and located proximal to the coupling band 901, can be shorter. The width of this proximal end piece 238 can taper along this shorter length to the width of the proximal control element 230. The tapered, shorter proximal end piece 238 can mitigate problems with inserting tools into the proximal opening. In general, wide proximal end pieces 238 can be longer than proximal end pieces 238 that taper to the width of the proximal control element 230.

[0104] A proximal region of the distal lumen segment 222 may contain one or more markers to allow visualization under fluoroscopy during loading / reloading of the catheter delivery element 300. For example, the proximal end region may include a section of Pebax (e.g., 35D) loaded with tungsten (80%) for radiopacity. In some implementations, the proximal tail 228 and / or the transition section 226, which defines the proximal opening into the lumen of the lumen segment 222, may be coated or embedded with a radiopaque material such that the opening into the lumen can be fully visualized during use. The radiopaque material embedded in this proximal end region may increase the outer diameter.

[0105] The distal end of the proximal control element 230 and / or the distal lumen section 222 may have features that facilitate mechanical connection during welding, such as a textured surface, protruding features, or cutouts. During a hot welding process, these features would facilitate mechanical connection between the polymeric distal lumen section 222 and the proximal control element 230. For example, the proximal end of the distal lumen section 222 may include a short fitting sleeve 240, as shown in Fig. Figures 6A-6F show a proximal edge 221 of the distal lumen section 222 connected to the inner lumen 240. The sleeve 240 can enclose an inner lumen extending between a proximal opening 242 and a distal opening 241. The distal end of the proximal control element 230 can be inserted through the proximal opening 242 and into the inner lumen of the sleeve 240 to connect the proximal control element 230 to the distal lumen section 222. In some implementations, the proximal control element 230 can be connected to the distal lumen section 222 such that a distal opening 231 of the hypotube forming the proximal control element 230 can communicate with the lumen 223 of the distal lumen section 222, for example, such that the distal opening 241 of the sleeve 240 communicates with it.The sleeve 240 can also provide a transition between the distal lumen section 222 and the proximal control element 230, similar to the proximal tail 238. The distal lumen section 222 does not need to include a matching sleeve 240 to connect to the proximal control element 230. For example, the distal end of the proximal control element 230 can be inserted through a wall of the proximal end piece 238 at the proximal end of the distal lumen section 222 (see Figure 2). Fig. 5A, 5E-5F). The distal end of the proximal control element 230 can extend along the length of the proximal end 238 and along at least one length of the wall of the distal lumen section 222.

[0106] The lumen section 222 of the catheter 200 can have a uniform diameter or wall thickness from the proximal end to the distal end, or the lumen section 222 can have different outer diameters or wall thicknesses along its length. For example, the most distal end of the distal lumen section 222 can have a smaller outer diameter compared to a more proximal region of the distal lumen section 222. Fig. 5A-5B, 5E-5F and the Fig. 6A-6B, 6E-6F and the Fig. Figure 8A shows a distal lumen section 222, which has a distal tubular region or distal tube 245 with a smaller outer diameter and a proximal tubular region or proximal tube 246 with a larger outer diameter. The distal tube 245 transitions into the proximal tube 246 via a step 247. As is best described in the Fig. 5A and Fig. As shown in Figure 6A, the inner diameters of the distal tube 245 and the proximal tube 246 are essentially the same, providing a uniformly smooth inner wall surface for the lumen 223. The outer diameter of the distal tube 245 may be smaller than the outer diameter of the proximal tube 246. The step 247 is formed by a change in wall thickness between the distal tube 245 and the proximal tube 246. In some implementations, the outer diameter of the distal tube 245 may be about 0.080 in to about 0.084 in, and the outer diameter of the proximal tube 246 may be about 0.087 in to about 0.088 in. In other implementations, the outer diameter of the proximal tube 246 may be between 0.106 in and about 0.107 in. The relative lengths of the proximal and distal tubes 245, 246 may vary, as described elsewhere herein.For example, the proximal tube 246 can form a proximal sealing zone, which has a cylindrical segment with a length of approximately 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, up to approximately 10 mm or 15 mm. The proximal sealing zone of the proximal tube 246 can have a larger outer diameter than the distal tube. In some implementations, the distal tube can have an outer diameter of approximately 0.082 inches, while the proximal tube 246 at the proximal sealing zone can have an outer diameter of approximately 0.087 inches. In other implementations, the distal tube can have an outer diameter of approximately 0.102 inches, and the proximal tube 246 at the proximal sealing zone can have an outer diameter of approximately 0.105 inches.

[0107] At least one section of the wall of the proximal tube 246 with a larger outer diameter may be interrupted, so that it encloses a slot 236 (see Fig. 5A-5C, 5E-5F, 6A-6C, and 6E-6F). The slot 236 can extend a distance along the proximal tube 246. The slot 236 can extend from an edge 221 of the proximal tube 246 over at least approximately 2 cm of the length of the proximal tube 246. The slot 236 can extend along the entire length of the proximal tube 246 to the location of the elevation 247, but need not. Additionally, the proximal tube 246 can include more than one slot 236. The slot 236 can be positioned in the larger-diameter proximal tube 246 at a location opposite the point where the distal end of the proximal control element 230 connects to the wall of the distal lumen section 222. The distal end of the proximal control element 230, which is embedded in the wall of the proximal tube 246, lies opposite the slot 236 (see Fig. 5C and Fig. 6C). The slot 236 can be positioned at another location around the proximal tube 246.

[0108] The slot 236 can allow a slight expansion of the proximal tube 246, so that the ends of the wall forming the slot 236 separate from each other, creating a gap between them. For example, when the catheter 200 is inserted through the working lumen of the sheath 400, the outer diameter can be accommodated in a sliding fit, leaving at least an overlap area 348. When suction is applied through the working lumen, for example, by applying suction from a suction source connected to the proximal end 403 of the guide sheath 400, the seal in the overlap area 348 can be improved by a slight enlargement of the gap formed by the slot 236.This slight expansion provides a better seal between the outer diameter of the proximal tube 246 and the inner diameter of the working lumen of the sheath 400, as the outer surface of the catheter walls 200 can press against the inner surface of the working lumen, creating a tight fit between the catheter 200 and the sheath 400. This improved seal between the outer surface of the catheter 200 and the inner surface of the working lumen minimizes the ingress of blood from the vessel into the working lumen directly through the distal opening 408. Thus, the larger outer diameter of the proximal tube 246, in combination with the slot 236, can improve the seal between the catheter 200 and the sheath 400 by accommodating variations in the inner diameter of the sheath. The slot 236 can effectively increase the outer diameter of the proximal tube 246, depending on the spacing of the walls forming the slot 236.The walls forming the slot 236 can be spaced apart, increasing the slot's width. The outer diameter of the proximal tube 246, including the increased width after the spacing between the walls forming the slot 236, can be equal to or greater than the inner diameter of the sheath through which the proximal tube 246 is inserted. This allows a single catheter to be compatible with a wider range of inner diameters. In some implementations, the outer diameter of the proximal tube 246 can be 0.081 in or approximately 0.100 in when the walls forming the slot 236 are abutting with no gap. The outer diameter of the proximal tube 246 can be increased to approximately 0.087 in or approximately 0.106 in when the walls forming the slot 236 are spaced at their maximum distance from each other.Furthermore, the increased wall thickness of the proximal tube 246 enables the creation of a more robust connection between the distal lumen section 222 and the proximal control element 230 of the catheter.

[0109] Additionally or alternatively, the distal tip 406 of the sheath 400 may include one or more features that improve the seal between the inner diameter of the working lumen of the sheath 400 and the outer diameter of the proximal end region of the catheter 200. Catheter delivery element

[0110] The distal access system 100 may, but need not, include a catheter advancement element 300 for introducing the catheter 200 into the distal anatomy. Likewise, the catheter advancement element 300 may be used with catheters other than the catheter 200 described herein. For example, the catheter advancement element 300 may be used to deliver a 5MAX reperfusion catheter (Penumbra, Inc., Alameda, CA) for the removal of blood clots in patients with acute ischemic stroke, or other reperfusion catheters known to the technique. Although the catheter advancement element 300 is described herein in relation to the catheter 200, it may be used to advance other catheters, and its use is not intended to be limited to this.

[0111] The Distal Access System 100 provides rapid and easy access to the distal target anatomy, particularly the tortuous anatomy of the cerebral vascular system. The flexibility and deliverability of the Distal Access Catheter 200 allow it to conform to the shape of the tortuous anatomy, avoiding the application of straightening forces that would create a new anatomical shape. The Distal Access Catheter 200 is capable of this even when the catheter advancement element 300 extends through its lumen. Thus, the flexibility and deliverability of the catheter advancement element 300 is equivalent to or better than the flexibility and deliverability of the distal lumen segment 222 of the Distal Access Catheter 200, as both are configured to reach the middle cerebral artery (MCA) without straightening the curves of the anatomy along the way.

[0112] The catheter delivery element 300 can include a non-expandable, flexible, elongated body 360 connected to a proximal section 366. The catheter delivery element 300 and the catheter 200 described herein can be configured for rapid exchange or over-the-wire procedures. For example, the flexible, elongated body 360 can be a tubular section extending the entire length of the catheter delivery element 300 and have a proximal opening from the lumen of the flexible, elongated body 360 configured to extend outside the patient's body during use. Alternatively, the tubular section can have a proximal opening positioned so that the proximal opening remains inside the patient's body during use.The proximal section 366 can be a proximal element connected to and extending proximal to a distal tubular section. A proximal opening of the tubular section can be positioned near the point where the proximal element connects to the tubular section. Alternatively, the proximal section 366 can be a proximal extension of the tubular section, extending to a proximal opening near a proximal end of the catheter delivery element 300 (i.e., outside the patient's body).

[0113] The configuration of the proximal section 366 can vary. In some implementations, the proximal section 366 is simply a proximal extension of the flexible elongated body 360, which does not change significantly in structure but does change in flexibility. For example, the proximal section 366 transitions from the highly flexible distal regions of the catheter delivery element 300 to less flexible proximal regions of the catheter delivery element 300. The proximal section 366 provides a relatively rigid proximal end suitable for manipulating and rotating the more distal regions of the catheter delivery element 300. In other implementations, the proximal section 366 is a hypotube. The hypotube may be exposed or coated with a polymer. In still other implementations, the proximal section 366 may be a polymer section reinforced by a wound band.The proximal section 366 can have the same outer diameter as the flexible elongated body or a smaller outer diameter than the flexible elongated body.

[0114] The proximal section 366 need not include a lumen. For example, the proximal section 366 may be a solid rod, band, or wire that does not have a continuous lumen connected to the tubular elongated body 360. When the proximal section 366 is described herein as having a lumen, it should be understood that the proximal section 366 may also be solid and not have a lumen. The proximal section 366 is generally less flexible than the elongated body 360 and may transition to a stiffer proximal end. Thus, the catheter delivery element 300 may have an extremely soft and flexible distal tip that transitions proximally into a stiff proximal section 366, which is well suited for rotating and sliding the distal elongated body 360.The transition in the flexibility of the catheter delivery element 300 and the system as a whole is described in more detail below and in the examples.

[0115] The elongated body 360 can be accommodated within the inner lumen 223 of the distal lumen section 222 of the catheter 200 and extend through it (see Fig. 2B). The elongated body 360 or tubular section may have an outer diameter. The outer diameter of the tubular section may have at least one abutment point, wherein the difference between the inner diameter of the catheter 200 and the outer diameter of the tubular section at the abutment point may not exceed approximately 0.010 in, for example, from 0.003 in to approximately 0.010 in, preferably from approximately 0.006 in to approximately 0.008 in. As described in more detail below, the catheter delivery element 300 may also include a tip section or distal tip 346 located distal to the at least one abutment point of the tubular section. The tip section may have a length and taper along at least one portion of its length. The distal tip 346 of the catheter delivery element 300 can extend beyond the distal end of the catheter 200, as shown in Fig. Figure 2B shows that the proximal section 366 of the catheter delivery element 300, or the proximal extension, is connected to and extends proximal to a proximal end region of the elongated body 360. The proximal section 366 may be less flexible than the elongated body 360 and may be configured for bidirectional movement of the elongated body 360 of the catheter delivery element 300 within the lumen section 222 of the catheter 200, as well as for movement of the catheter system 100 as a whole. The elongated body 360 may be inserted coaxially through the inner lumen 223 of the lumen section 222. The outer diameter of at least one region of the elongated body 360 may be dimensioned such that it substantially fills at least one section of the inner lumen 223 of the lumen section 222.

[0116] The overall length of the catheter delivery element 300 (e.g., between the proximal end and the most distal tip) varies, but is generally long enough to extend through the carrier 200 and at least one distance beyond the distal end of the carrier 200, while at least one length of the proximal section 366 remains outside the proximal end of the guide sheath 400 and outside the patient's body. In some implementations, the overall length of the catheter delivery element 300 is approximately 145 to 150 cm, with a working length of approximately 140 to 145 cm from a proximal tab or hub to the most distal tip.The elongated body 360 can have a length at least as long as the lumen section 222 of the catheter 200, although the elongated body 360 may be shorter than the lumen section 222, provided that at least a minimum length remains within the lumen section 222 when a distal portion of the elongated body 360 is extended distal to the distal end of the lumen section 222 to form a fixed point or area with the catheter. In some implementations, this minimum length of the elongated body 360 remaining within the lumen section 222 when the distal tip 346 is positioned in its optimal advancement configuration is at least approximately 5 cm, at least approximately 6 cm, at least approximately 7 cm, at least approximately 8 cm, at least approximately 9 cm, at least approximately 10 cm, at least approximately 11 cm, or at least approximately 12 cm up to approximately 50 cm.In some implementations, the shaft length of the distal lumen section 222 may be approximately 35 cm to approximately 75 cm and shorter than the working length of the guide sheath, and the insertion length of the elongated body 360 may be at least approximately 45 cm, 46 cm, 47 cm, 48 cm, 48.5 cm, 49 cm, 49.5 cm up to approximately 85 cm.

[0117] The length of the elongated body 360 can allow the distal end of the elongated body 360 to reach cerebrovascular targets within, for example, the M1 or M2 regions, while the proximal end of the elongated body 360 remains proximal to or below the level of severe bends along the insertion path. For example, the catheter system entry point may be in the femoral artery, and the target embolus may be distal to the right common carotid artery (RCC), such as within the M1 segment of the middle cerebral artery on the right side.The proximal end of the elongated body 360, where it transitions into the proximal section 366, can remain within a vessel proximal to highly tortuous anatomy, such as the carotid siphon, the right common carotid artery (RCC), the brachiocephalic trunk (BT), the branch into the brachiocephalic artery from the aortic arch (AA), or the branch from the aortic arch (DA). This avoids the stiffer proximal section 366, or the transition of material between the stiffer proximal section 366 and the long body 360, having to navigate the bend of the aortic arch or the bend of the brachiocephalic branch from the aortic arch, both of which can be very pronounced. The lengths described herein for the distal lumen section 222 can also apply to the elongated body 360 of the catheter delivery element.

[0118] The proximal section 366 can also have a varying length. In some implementations, the proximal section 366 is approximately 90 cm to approximately 95 cm long. The distal section, which extends distally to the distal end of the lumen section 222, may include a distal tip 346 that projects beyond the distal end of the lumen section 222 during use of the catheter advancement element 300. The distal tip 346 of the elongated body 360 is configured to project distally from the distal end of the lumen section 222 during advancement of the catheter 200 through the tortuous anatomy of the cerebral vessels, as described in more detail below. The proximal section 366, which is connected to and extends proximal to the elongated body 360, can generally be aligned laterally next to the proximal control element 230 of the catheter 200.The arrangement between the elongated body 360 and the lumen section 222 can be maintained during the advancement of the catheter 200 through the tortuous anatomy to reach the target site for treatment in the distal vessels, and helps to prevent the distal end of the catheter 200 from becoming entangled in tortuous branched vessels, as described in more detail below.

[0119] In some implementations, the elongated body 360 may have a region of relatively uniform outer diameter extending along at least part of its length, and the distal tip 346 tapers from this uniform outer diameter. The outer diameter of the elongated body 360 may have a step at some point along its length, for example, a step in the outer diameter at a proximal end region where the elongated body 360 connects to the proximal section 366. Depending on the inner diameter of the catheter 200, the gap between the catheter 200 and the outer diameter of the elongated body 360 along at least part of its length may not exceed approximately 0.010 in, such as within a range of approximately 0.003 in to 0.010 in or between 0.006 in and 0.008 in.

[0120] The elongated body 360 can have an overall shape profile from the proximal end to the distal end, transitioning from a first outer diameter with a first length to a tapered outer diameter with a second length. The first length of this first outer diameter region (i.e., the close-fitting region between the distal lumen section 222 and the elongated body 360) can be at least approximately 5 cm or 10 cm up to approximately 50 cm. The length of the tapered outer diameter can be between 1 cm and 4 cm. When the catheter delivery element 300 is introduced through the catheter 200, this tapered distal tip 346 is configured to extend beyond and protrude from the distal end of the lumen section 222, while the more proximal region of the body 360 (i.e., the first length described above) remains within the lumen section 222.

[0121] As mentioned, the distal end of the lumen section 222 can be blunt and exhibit no change in the dimension of the outer diameter, while the distal tip 346 can be tapered, thus providing an overall elongated, tapered geometry of the catheter system. The outer diameter of the elongated body 360 also approaches the inner diameter of the lumen section 222, thus minimizing the rise from the elongated body 360 to the outer diameter of the lumen section 222. By preventing this rise, problems are avoided with the lip formed by the distal end of the lumen section 222, which can become entangled in the tortuous neurovascular structure, such as around the carotid siphon near the branch of the ophthalmic artery, as the distal tip 346, in combination with the distal end of the catheter 200, bends and curves along the vascular anatomy.In some implementations, the inner diameter of the lumen section 222 can be at least approximately 0.052 inches, approximately 0.054 inches, and the maximum outer diameter of the elongated body 360 can be approximately 0.048 inches, so the difference between them is approximately 0.006 inches. In some implementations, the inner diameter of the lumen section 222 can be approximately 0.070 inches and the maximum outer diameter of the elongated body 360 can be approximately 0.062 inches, so the difference between them is approximately 0.008 inches. In some implementations, the inner diameter of the lumen section 222 can be approximately 0.088 inches and the maximum outer diameter of the elongated body 360 can be approximately 0.080 inches, so the difference between them is approximately 0.008 inches.In some implementations, the inner diameter of lumen segment 222 may be approximately 0.072 inches and the maximum outer diameter of elongated body 360 approximately 0.070 inches, so the difference between them is only 2 thousandths of an inch. In other implementations, the maximum outer diameter of elongated body 360 is approximately 0.062 inches, so the difference between them is approximately 0.010 inches. Although the outer diameter of elongated body 360 extends through the lumen of lumen segment 222, lumen segment 222 and the elongated body 360 extending coaxially through it are flexible enough to traverse the tortuous anatomy leading to the level of the M1 or M2 arteries without kinking or damaging the vessel.

[0122] The dimensions provided herein are approximate values, and each dimension may have an engineering tolerance or permissible deviation limit. The use of the terms "about" or "approximately" is intended to indicate such permissible tolerance for the dimension in question. Where "about" or "approximately" is not used herein with a particular dimension, that dimension need not be exact.

[0123] The length of the distal tip 346 (e.g., the region of the catheter advance element 300 configured to extend distally to the distal end of the catheter 200 during use to achieve the optimal advance configuration) can vary. In some implementations, the length of the distal tip 346 may range from approximately 0.50 cm to approximately 4.0 cm from the most distal end of the elongated body 360, or from approximately 1.0 cm to approximately 3.0 cm. In other implementations, the length of the distal tip 346 ranges from 2.0 cm to approximately 2.5 cm. In some implementations, the length of the distal tip 346 varies depending on the inner diameter of the catheter 200 with which the catheter advance element 300 is to be used.For example, the length of the distal tip 346 may be shorter (e.g., 1.2 cm) for a catheter feeder element 300 designed to be used with a catheter 200 with an inner diameter of approximately 0.054 in, and longer (e.g., 2.5 cm) for a catheter feeder element 300 designed to be used with a catheter 200 with an inner diameter of approximately 0.088 in. The distal tip 346 can have a constant taper from the outer diameter of the elongated body 360 (e.g., the distal end of mark 344b) to a second, smaller outer diameter at the most distal end (e.g., the proximal end of mark 344a), as shown in . Fig. Figure 7C shows that in some implementations, the constant taper of the distal tip 346 can range from an outer diameter of approximately 0.048 in to an outer diameter of approximately 0.031 in over a length of approximately 1 cm. In other implementations, the constant taper of the distal tip 346 can range from an outer diameter of 0.062 in to an outer diameter of approximately 0.031 in over a length of approximately 2 cm. In yet other implementations, the constant taper of the distal tip 346 can range from an outer diameter of 0.080 in to an outer diameter of approximately 0.031 in over a length of approximately 2.5 cm. The length of the constant taper of the distal tip 346 can vary, for example, between 0.8 cm and approximately 2.5 cm, or between 1 cm and 3 cm, or between 2.0 cm and 2.5 cm. The angle of the taper can vary 360° depending on the outer diameter of the elongated body.For example, the taper can have an angle between 0.9 and 1.6 degrees relative to the horizontal. The taper can have an angle between 2 and 3 degrees from a centerline of the elongated body 360°.

[0124] The catheter delivery element 300 can include a distal tip 346 that tapers along its length. The elongated body 360 of the catheter delivery element 300 can have an inner diameter that remains constant along its length, even with the tapered distal tip 346. Thus, the inner diameter of the lumen extending through the tubular section of the catheter delivery element 300 can remain uniform, and the wall thickness of the distal tip 346 can be reduced to accommodate the taper. The wall thickness can decrease distally along the length of the taper. Therefore, the material properties, including the wall thickness, angle, and length of the taper, can contribute to maximizing the overall flexibility of the distal end of the distal tip 346.The catheter delivery element 300 changes in its flexibility from the distal end to the point of contact, where it achieves an outer diameter that differs from that of the catheter 200 by no more than about 0.010 inch.

[0125] The distal tip 346 need not be conical and can achieve its soft, atraumatic, and flexible characteristics due to a property of the material that is not based on a change in external dimensions, in order to facilitate endovascular navigation to an embolus in a tortuous anatomy. Additionally or alternatively, the distal tip 346 of the elongated body 360 can exhibit a transition in flexibility along its length. The most flexible region of the distal tip 346 may be its distal end, extending along the length of the distal tip 346 from the distal end toward a region proximal to the distal end.For example, the distal tip 346 may be formed from a material with a hardness of no more than 35D or approximately 62A, and proximally transition to a flexible region where it is formed from a material with a hardness of no more than 55D and 72D up to the proximal section 366, which may be a stainless steel hypotube or a combination of a material property and a conical shape. The materials used to form the regions of the elongated body 360 may include PEBAX (such as PEBAX 25D, 35D, 55D, 72D) with a lubrication additive compound, such as Mobilize (Compounding Solutions, Lewiston, Maine). In some implementations, the material used to form a region of the elongated body 360 may be Tecothane 62A.By incorporating a lubricating additive directly into the polymeric elongated body, the incorporation of a separate lubricating lining, such as a Teflon lining, is unnecessary. This allows for a more flexible element that can move through the distal cerebral anatomy and is less prone to kinking. Similar materials can be used to form the distal lumen section 222 of the catheter 200, providing similar advantages. The flexibility of the distal tip 346 can be achieved through a combination of flexible lubricating materials and conical shapes. For example, the length of the tip 346 can be kept shorter than 2 cm to 3 cm, while maintaining optimal insertability due to a change in the flexible material from the distal tip to a more proximal region, thus maintaining a distance between the distal tip and the more proximal region.In one implementation, the elongated body 360 is made of PEBAX (polyether block amide) with embedded silicone designed to exhibit maximum flexibility. The wall thickness of the distal end of the lumen section 222 can also be designed to be so thin as to minimize the lip formed by the distal end of the lumen section 222 relative to the elongated body 360.

[0126] The elongated body 360 offers an advantage over a microcatheter in that it can have a relatively large outer diameter, only 0.003 to 0.010 inches smaller than the inner diameter of the distal lumen section 222 of the catheter 200, while still maintaining a high degree of flexibility to navigate through tortuous anatomical structures. If the gap between the two components is too small (e.g., below approximately 0.003 inches), the force required to slide the catheter advancer 300 relative to the catheter 200 can damage one or both components and increase the risk to the patient during the procedure. The gap results in a fit that is too tight to provide optimal relative sliding. If the gap between the two components is too large (e.g.,(larger than about 0.010 inches), the distal end of the 200 catheter forms a lip that tends to become entangled in branched vessels during advancement through tortuous neurovasculature, such as around the carotid siphon where the ophthalmic artery branches off.

[0127] The difference between the inner and outer diameters of the elongated body 360 and the distal lumen segment 222 can lie within this size range (e.g., 0.003 in - 0.010 in) along much of its length. For example, the elongated body 360 may have a relatively uniform outer diameter ranging from about 0.048 in to about 0.080 in from the proximal end to the distal end, up to the point where the tapering of the distal tip 346 begins. Similarly, the distal lumen segment 222 of the catheter 200 may have a relatively uniform inner diameter ranging from about 0.054 in to about 0.088 in from the proximal end to the distal end. Thus, the difference between their respective inner and outer diameters can lie within this gap size range of 0.003 inches to 0.010 inches over most of their length.The distal tip 346 of the elongated body 360, which tapers, has a larger gap relative to the inner diameter of the distal lumen section 222. However, during use, this tapered distal tip 346 is configured to extend distally to the distal end of the catheter 200, so that the portion of the elongated body 360, which has an outer diameter matched to the inner diameter of the distal lumen section 222, is positioned within the lumen of the catheter 200, thus minimizing the lip at the distal end of the catheter 200.

[0128] The elongated body 360 can be manufactured from various materials that provide suitable flexibility and lubricity. Examples of such materials include high-density polyethylene, 72D PEBAX, 90D PEBAX, or materials with equivalent stiffness and lubricity. At least a portion of the elongated body 360 may be reinforced to improve navigation and torque (e.g., by a braided reinforcement layer). The flexibility of the elongated body 360 can be increased toward the distal tip 346, so that the distal portion of the elongated body 360 is softer and more flexible, and easier to articulate and bend than a more proximal portion. For example, a more proximal portion of the elongated body may exhibit a bending force flexible enough to navigate tortuous anatomies such as the carotid siphon without kinking.If the elongated body 360 has a braided reinforcing layer along at least part of its length, the braided reinforcing layer can terminate at a distance proximal to the distal tip 346. For example, the distance from the end of the braid to the distal tip can be approximately 10 cm to approximately 15 cm, or approximately 4 cm to approximately 10 cm, or approximately 4 cm to approximately 15 cm.

[0129] In some implementations, the elongated body 360 can be generally tubular along at least part of its length, such that it has a single lumen 368 extending parallel to a longitudinal axis of the catheter delivery element 300 (see Fig. 7A-7C and also Fig. 10A-10C). In one implementation, the single lumen 368 of the elongated body 360 is dimensioned to accommodate a guidewire; however, the use of the catheter delivery element 300 generally eliminates the need for a guidewire. Methods for using the catheter delivery element 300 without a guidewire to position a catheter in distal regions of the brain are described in more detail below.

[0130] A guidewire can generally extend concentrically through the single lumen 368 from a proximal opening to a distal opening through which the guidewire can extend. In some implementations, the proximal opening is located at the proximal end of the catheter delivery element 300, such that the catheter delivery element 300 is configured for over-the-wire (OTW) procedures. In other implementations, the proximal opening is a quick-change opening 362 through a wall of the catheter delivery element 300, such that the catheter delivery element 300 is configured for a quick-change instead of, or in addition to, OTW. In this implementation, the proximal opening 362 extends through the side wall of the elongated body and is located at a distance from a proximal tab 364 and distal to the proximal section 366 (see Fig. 7A-7B and 7D). The proximal opening 362 can be located at a distance of approximately 10 cm to approximately 20 cm from the distal tip 346. In some implementations, the proximal opening 362 may be located at a point where the elongated body 360 connects to the proximal section 366, for example, directly distal to one end of the hypotube (see Fig. 7B). In other implementations, the proximal opening 362 is located further distally, approximately 10 cm to approximately 18 cm from the most distal end of the elongated body 360 (see Fig. 7D). A proximal opening 362, located closer to the distal tip 346, facilitates easier removal of the catheter advancement element 300 from the catheter 200, while the catheter guidewire remains in place for a "quick-change" procedure. Quick-changes can be performed by a single person. The catheter advancement element 300 can be easily replaced with another device, with the same guidewire remaining in position. The single lumen 368 of the elongated body 360 can be configured to accommodate a guidewire with a diameter ranging from 0.014 in to 0.018 in or from 0.014 in to 0.022 in. In this implementation, the inner lumen diameter of the elongated body 360 can range from 0.020 in to 0.024 in.The guidewire, the catheter delivery element 300, and the catheter 200 can all be arranged coaxially to be inserted through the working lumen of the guide sheath 400. The inner diameter of the lumen 368 of the elongated body 360 can be between 0.019 inches and approximately 0.021 inches.

[0131] Fig. Figure 7D shows another implementation of the catheter advance element 300 configured for rapid exchange. Rapid exchange configurations can significantly reduce the device length, decrease manpower requirements, and shorten fluoroscopy time. As in other embodiments described herein, the catheter advance element 300 may comprise a non-expandable, flexible, elongated body 360 connected to a proximal section 366, which in turn is connected to a proximal tab 364 or a hub 375. The area near the distal tip 346 may be tapered such that the outer diameter tapers over a length of about 1 cm to about 4 cm. In some implementations, the distal taper length is 2.5 cm. In some implementations, the distal tip 346 tapers from about 0.080 in to about 0.031 in. Furthermore, the distal tip 346 can be made of a material with a material hardness (e.g.62A and 35D) are formed, which proximally changes the hardness of the materials (e.g., 55D and 72D) up to the proximal section 366. For example, illustrated. Fig. 7D the segment 371 of the elongated body 360 including the distal tip 346, which is formed from a material with a material hardness of 35D and a length of about 10 cm to about 12.5 cm.

[0132] Segment 371 of the elongated body 360, including the distal tip 346, is made of a material with a hardness of 62A and is approximately 10 cm to 12.5 cm long. Segment 372 of the elongated body 360 is made of a material with a hardness of 55D and is approximately 5 cm to 8 cm long. Segment 373 of the elongated body 360 is made of a material with a hardness of 72D and can be approximately 25 cm to 35 cm long. The three segments 371, 372, and 373 together form an insertion length of the elongated body 360, from the point where the proximal section 366 is connected to the elongated body 360 to the end of the distal tip 346, which can be approximately 49 cm long.

[0133] The Fig. Figures 10A-10C illustrate an implementation of a catheter delivery element 300 with a reinforcing layer 380. The reinforcing layer 380 can be a braid or another type of reinforcement to improve the torque capability of the catheter delivery element 300 and to help bridge the components of the catheter delivery element 300 with such differences in flexibility. The reinforcing layer 380 can bridge the transition from the rigid proximal section 366 to the flexible elongated body 360. In some implementations, the reinforcing layer 380 can be a braid positioned between the inner and outer layers of Pebax 382, ​​384 (see Figure 10A-10C). Fig. 10C). The reinforcement layer 380 can terminate at a distance proximal to the distal tip section 346. For example, shows Fig. 10A the elongated body 360 with segment 371 and segment 373, which are arranged proximal to segment 371. Segment 371 may include the distal tip 346, which is formed from a material with a material hardness of at most about 35D. Segment 371 is an unreinforced polymer that has a length of about 4 cm to about 12.5 cm. Segment 373 of the elongated body 360, which is located proximal to segment 371, may include the reinforcing layer 380 and extend a total of about 37 cm to the unreinforced distal segment 371. A proximal end region of the reinforcement layer 380 can overlap with a distal end region of the proximal section 366, such that a small overlap of hypotube and reinforcement is present near the transition between the proximal section 366 and the elongated body 360.

[0134] With regard to Fig. In 7D, an entry port 362 for a procedural guide wire can be positioned at a distance from the most distal end of the elongated body 360. In some implementations, the entry / exit port 362 can be located approximately 18 cm from the most distal end, creating a segment 370 for quick wire exchange. The outer diameter of the elongated body 360 within segment 370 (segments 371 and 372) can be approximately 0.080 to 0.082 inches, while segment 373 proximal to this quick-exchange wire entry / exit segment 370 has a reduced outer diameter of approximately 0.062 to 0.064 inches.

[0135] The tubular section of the catheter delivery element may have an outer diameter that includes at least one contact point. The difference between the outer diameter at the contact point and the inner diameter of the lumen at the distal end of the distal section may not exceed approximately 0.010 inches. The at least one contact point of this tubular section may be a point along its length. The length of the at least one contact point of this tubular section may range from at least approximately 5 cm to approximately 50 cm, including, for example, at least approximately 6 cm, at least approximately 7 cm, at least approximately 8 cm, at least approximately 9 cm, at least approximately 10 cm, at least approximately 11 cm, or at least approximately 12 cm to approximately 50 cm. This length need not be uniform, so the contact point need not be tight along its entire length.For example, the tightly fitting area may include ribs, grooves, slots, or other surface features.

[0136] In other implementations, the entire catheter delivery element 300 can be a tubular element configured to accommodate a catheter guidewire through both the proximal section 366 and the elongated body 360. For example, the proximal section 366 can be a hypotube or a tubular element with a lumen that communicates with the lumen 368 extending through the elongated body 360 (shown in Fig. 3) In some implementations, the proximal section 366 may be a peeled stainless steel hypotube coated with PTFE and having an outer diameter of 0.026 in. In other implementations, the outer diameter may range from 0.024 in to 0.030 in. In some implementations, such as an over-the-wire version, the proximal section 366 may be a beveled hypotube connected to a proximal hub 375. The proximal section 366 may be eccentric or concentric to the distal lumen section 222. As is best in Fig. As shown in Figure 7E, the proximal section 366 can be a stainless steel hypotube. The proximal section 366 can be a solid metal wire with a round or oval shape. The proximal section 366 can be a flattened wire strip with a rectangular shape. The wire strip can be bent into a circle, oval, C-shape, quarter circle, or other shape along an arc. The proximal section 366 can have a variety of shapes, whether or not a lumen extends through it, including a circular, oval, C-shaped, D-shaped, or other shape. In some implementations, the proximal section 366 is a D-shaped hypotube such that one inward-facing side is flat and one outward-facing side is rounded. The rounded side of the proximal section 366 can be shaped to engage with a correspondingly rounded inner surface of the sheath 400.The hypotube may have a lubricating coating such as PTFE. The hypotube may have an inner diameter of approximately 0.021 in, an outer diameter of approximately 0.0275 in, and an overall length of approximately 94 cm, providing a working length of approximately 143 cm for the catheter delivery element 300. Including the proximal hub 375, the catheter delivery element 300 may have an overall length of approximately 149 cm. In some implementations, the hypotube may be a tapered section approximately 100 mm long, starting proximally with a thickness of 0.3 mm and ending with a thickness of 0.10 mm to 0.15 mm. In other implementations, the elongated body 360 may be a solid element connected to the proximal section 366 and lacking a guidewire lumen.

[0137] The proximal section 366 is in the Fig. 2A, 7A-7D, and 10A are shown with a smaller outer diameter, which is less than the outer diameter of the elongated body 360. The proximal section 366 need not have a decrease in outer diameter and may also have the same outer diameter as the elongated body 360. For example, the proximal section 366 may contain a tube or other stiffening element coated with one or more polymer layers, thereby making the proximal section 366 essentially the same outer diameter as the elongated body 360.

[0138] How best to in the Fig. As shown in Figures 7F-7J, the proximal end of the proximal section 366 can be connected to a proximal hub 375. The proximal hub 375 can be an overmolded component having a Luer thread 377 and a Luer taper 378 formed on an inner surface of the proximal hub 375. The proximal hub 375 can have a tab 364 to facilitate clamping by the user. The proximal hub 375 prevents the catheter advancement element 300 and the catheter 200 from advancing beyond the distal tip of the base sheath 400 or the guide catheter by limiting insertion into the proximal RHV 434, which is an important functional and safety feature for the proper operation of the system 10.

[0139] At least a portion of the massive elongated body 360, such as the elongated distal tip 346, can be formed from a malleable material in which it is embedded or to which it is attached, tapering to a smaller dimension at a distal end. The distal tip 346 can be shaped at a desired angle or in a desired form, similar to how a guide wire can be used. The malleable length of the elongated body 360 can be at least approximately 1 cm, 3 cm, 5 cm, and up to approximately 10 cm, 15 cm, or longer. In some implementations, the malleable length can be approximately 1%, 2%, 5%, 10%, 20%, 25%, 50%, or more of the total length of the elongated body 360. In some implementations, the catheter feed element 300 may have a working length of approximately 140 cm to approximately 143 cm, and the elongated body 360 may have an insertion length of approximately 49 cm.The insertion length can be the PEBAX portion of the elongated body 360, which is approximately 49.5 cm. Thus, the malleable length of the elongated body 360 can range from approximately 0.5 cm to approximately 25 cm or more. The change in shape can be a function of manual shaping of the malleable length by the user prior to insertion, or the tip can be pre-shaped to a specific angle or curvature at the time of manufacture. Alternatively, the change can be reversible and actuated, such that, upon activation by a user, the tip forms the desired shape, allowing the tip to be used in a straight shape until the user requests a change. The catheter delivery element 300 can also include a shaping mandrel extending through the lumen of the elongated body 360, such that a physician can shape the distal tip 346 into a desired form at the time of use.Thus, the malleable distal tip 346 can be integrated into an elongated body 360 with a guide wire lumen.

[0140] The elongated body 360 can extend over the entire length of the catheter 200, including the distal lumen section 222 and the proximal control element 230, or the elongated body 360 can include the proximal section 366, which is generally oriented laterally adjacent to the proximal control element 230 of the catheter 200. The proximal section 366 of the elongated body 360 can be positioned coaxially or eccentrically to the elongated body 360. The proximal section 366 of the elongated body 360 can have a lumen extending through it. Alternatively, the section 366 can be a solid rod or a band without a lumen.

[0141] Again, with regard to the Fig. 7A-7D, the elongated body 360, similar to the distal lumen section 222 of the catheter 200, may have one or more radiopaque markers 344 along its length. The one or more markers 344 may vary in size, shape, and location. One or more markers 344 may be placed along one or more parts of the catheter delivery element 300, such as a tip-to-tip marker, a tip-to-taper marker, an RHV proximity marker, a fluoro-saver marker, or other markers that provide various information regarding the relative position of the catheter delivery element 300 and its components. In some implementations, and as is best described in Fig. As shown in Figure 7C, a distal end region can have a first radiopaque marker 344a, and a second radiopaque marker 344b can be arranged to indicate the boundary between the tapering of the distal tip 346 and the more proximal region of the elongated body 360 with a uniform or maximum outer diameter. This provides the user with information regarding optimal extension of the distal tip 346 in relation to the distal end of the lumen section 222 in order to minimize the lip at this distal end of the lumen section 222 for advancement through tortuous anatomy.In other implementations, for example, if the distal tip 346 is not necessarily tapered but instead exhibits a change in overall flexibility along its length, the second radiopaque marker 344b can be positioned to indicate the location where the relative flexibilities of the elongated body 360 (or the distal tip 346 of the elongated body 360) and the distal end of the lumen section 222 are substantially equal. The marker material can be a platinum / iridium ribbon, a polymer impregnated with tungsten, platinum, or tantalum, or another radiopaque marker that does not impair the flexibility of the distal tip 346 and the elongated body 360. In some implementations, the radiopaque markers are extruded PEBAX loaded with tungsten for radiopacity.In some implementations, the proximal marker band may be approximately 2.0 mm wide and the distal marker band approximately 2.5 mm wide to provide distinguishable information about the distal tip 346.

[0142] The proximal control element 230 of the catheter 200 can include a proximal tab 234 at its proximal end. Similarly, the proximal section 366 connected to the elongated body 360 can include a tab 364. The tabs 234 and 364 can be configured to be detachably and adjustableally connected to each other and / or to their respective proximal sections. This coupling allows the catheter advance element 300 to reversibly connect to the catheter 200, locking (and unlocking) the relative extension of the distal lumen section 222 and the elongated body 360. This allows the catheter 200 and the catheter advance element 300 to be advanced as a single unit. In the locked configuration, the tab 364 or the proximal section 366 can engage with the catheter tab 234.In the unlocked configuration, the tab 364 and the catheter tab 234 can be released. The tab 364 or the proximal section 366 can, for example, engage with or lock into the catheter tab 234 to maintain the relationships between the corresponding section of the elongated body 360 and the catheter 200 in the locked configuration. The tab 364 can be a feature on the proximal hub 375, such as the hub 375 in the [reference missing]. Fig. 7F-7J.

[0143] Such a locking mechanism can be achieved, for example, by using a detent on the tab 364 that engages in a recess formed in the catheter tab 234, or vice versa. For example, the tab 234 of the catheter 200 can form a ring with a central opening extending through it. The tab 364 of the body 360 can have an annular detent with a central pin dimensioned such that it can be inserted through the central opening of the tab 234, so that the ring of the tab 234 is received in the annular detent of the tab 364, forming a single gripping element with which a user can advance and / or retract the catheter system through the access sheath. The tabs 234 and 364 can be fixed or movable to accommodate different relative positions between the elongated body 360 and the lumen section 222 of the catheter 200.In some implementations, a proximal end of the proximal control element 230 of the catheter 200 may include a coupling element 334, such as a clamp, a clip, a C-shaped element, or another connector configured to accommodate the proximal section 366 of the catheter feed element 300 (see . Fig. 2A). The coupling element 334 can be configured to engage with the proximal section 366 by an interference fit, such that a first force is required to insert the proximal section 366 into the clamp of the tab 234, and a second, greater force is required to remove the proximal section 366 from the clamp of the tab 234. However, after the proximal section 366 is inserted into the coupling element 334, the catheter delivery element 300 and the catheter 200 can still be moved relative to each other along a longitudinal axis of the system. The force required to move the relative position of the two components can be dimensioned such that unintentional adjustment is avoided and the relative position can be maintained during use, but can be adjusted if intentionally changed.The coupling configuration between the proximal section 366 of the catheter delivery element 300 and the proximal control element 230 of the catheter 200 can vary. Generally, however, the coupling is configured to be reversible and adjustable while providing sufficient retention force between the two elements in a relatively user-friendly manner (e.g., allowing one-handed operation) and organizing the proximal ends of the components (e.g., preventing the proximal control element 230 and the proximal section 366 from twisting and entangling). The coupling feature 334, configured to prevent entanglement and aid in organizing the proximal sections, may be integrated into the tabs or be a separate feature located along their proximal end region.

[0144] The catheter delivery element 300 can be positioned in a locked configuration with the catheter 200, which is configured for improved guidance through a tortuous and frequently diseased vascular system in acute ischemic stroke. Other configurations are considered herein. For example, the elongated body 360 can include one or more detents on an outer surface. The detents can be located near a proximal end and / or a distal end of the elongated body 360. The detents are configured to lock with appropriately shaped surface features on the inner surface of the lumen segment 222 through which the elongated body 360 extends. The catheter delivery element 300 and the catheter 200 can have more than a single locking point between them.For example, a coupling element 334, such as a clamp, a clip, a C-shaped element or other connector, may be provided that is configured to hold together the catheter feed element 300 and the proximal control element 230 or the tab 234 of the catheter 200.

[0145] In some implementations, the proximal control element 230 of the catheter 200 can run along or within a special channel of the proximal section 366. The channel can be located along the length of the proximal section 366 and have a shape corresponding to the shape of the proximal control element 230 of the catheter, such that the proximal control element 230 of the catheter 200 can be received in the channel and slide smoothly in both directions along the channel. Once the catheter 200 and the elongated body 360 are fixed, the combined system, i.e., the catheter 200 and the catheter delivery element 300, can be brought to a target location, for example, through the working lumen of the guide sheath 400 described elsewhere herein.

[0146] The catheter advancement element 300 (regardless of whether it contains the reinforcement layer or not), loaded into the lumen of the catheter 200, can be used to advance the catheter 200 to distal regions of the brain (e.g., at the level of the MCA). The conventional approach for the Circle of Willis involves using a triaxial system that includes a catheter guidewire placed within a conventional microcatheter, which is itself located within an intermediate catheter. The entire coaxial system may extend through a base catheter or base sheath. The sheath is typically positioned so that its distal tip is placed in a high cervical carotid artery. The coaxial systems are often advanced together to approximately the terminal carotid artery, at which point the conventional coaxial systems must be advanced stepwise in separate throws.This is due to the two successive 180-degree or larger rotations (see . Fig. 1A-1C). The first 180-degree turn is located at the level of the petrous bone to the cavernous internal carotid artery. The second 180-degree turn is located at the terminal cavernous carotid artery as it passes through and bifurcates into the anterior cerebral artery (ACA) and the middle cerebral artery (MCA). This S-shaped region is referred to herein as the "siphon" or "carotid siphon." The ophthalmic artery arises from the cerebral ICA, which is a common point of catheter entrapment during access to the anterior circulation.

[0147] Conventional microcatheter systems can be advanced over a guidewire to the anterior circulation. The inner diameter of the conventional microcatheter is significantly larger than the outer diameter of the guidewire over which it is advanced, creating a lip at a distal region of the system that can become entangled on these lateral branches during passage through the siphon. Conventional microcatheter systems (i.e., catheter-guidewire, microcatheter, and intermediate catheter) are not advanced in a single, smooth passage, but rather sequentially through the bends of the carotid siphon to the distal target sites. The bends of the carotid siphon are negotiated one at a time using a stepwise advancement technique. For example, the carotid siphon must be traversed. The conventional microcatheter is held in place while the guidewire alone advances an initial distance (i.e.,The conventional microcatheter is advanced through the first bend of the siphon. The guidewire is then held in place while the conventional microcatheter is advanced over the guidewire through the first bend. The conventional microcatheter and catheter guidewire are then held in place while the intermediate catheter is advanced over the microcatheter and catheter guidewire through the first bend. This process is repeated to traverse the second bend of the siphon, which is generally considered the more difficult turn into the cerebral vessel. The microcatheter and intermediate catheter are held in place while the catheter guidewire is advanced a second distance (i.e., through the second bend of the siphon). Finally, the guidewire and interventional catheter are held in place while the microcatheter is advanced over the guidewire through the second bend.The guidewire and microcatheter are then secured, while the interventional catheter is advanced through the second turn alone. This multi-step procedure is a time-consuming process requiring multiple people who must perform several hand changes on the components. For example, two hands are needed to secure and slide the components over each other, forcing the user to perform the steps sequentially. The stepwise procedure is necessary because the incremental changes between these components (e.g., catheter-guidewire, microcatheter, and intermediate catheter) would make advancement too difficult.

[0148] In contrast, the Catheter 200 and Catheter Advancer 300 eliminate this multi-stage, stepwise procedure for advancing the components to gain access to distal sites via the siphon. The Catheter 200 and Catheter Advancer 300 can be advanced as a single unit through both turns of the carotid siphon CS. Both turns can be traversed in a single, smooth pass or throw to a target in a cerebral vessel without the need to stepwise adjust their relative extensions and without relying on the conventional stepwise advancement technique used with traditional microcatheters. The Catheter 200, with the Catheter Advancer 300 extending through it, allows a user to advance them together in the same relative position from the first bend of the siphon through the second bend, beyond the terminal cavernous carotid artery, into the ACA and MCA.It is important that the two components can be advanced in a single, smooth movement through both bends without changing the hand position.

[0149] The catheter advance element 300 can be positioned adjacent to the catheter 200 in a way that provides optimal relative extension between the two components for a single, smooth advance. The catheter advance element 300 can be positioned through the lumen of the catheter 200 such that its distal tip 346 extends beyond a distal end of the catheter 200. The distal tip 346 of the catheter advance element 300 eliminates the step-like transition between the inner element and the outer catheter 200, thus preventing problems with entanglement on branched vessels within the vascular system, allowing the catheter 200 to easily navigate the multiple angled bends of the carotid siphon CS. The optimal relative extension could, for example, be the distal tip 346 of the elongated body 360 extending distally to a distal end of the catheter 200.The length of the distal tip 346, which extends distally to the distal end of the catheter 200 during advancement, can range from 0.5 cm to approximately 4 cm. This alignment can be achieved by intervention with a mechanical element or simply by the user holding the two components together.

[0150] The components can be advanced with a guidewire, over a pre-positioned guidewire, or without a guidewire at all. In some implementations, the guidewire can be pre-assembled with the catheter delivery element 300 and the catheter 200 such that the guidewire extends through one lumen of the catheter delivery element 300, which is loaded through one lumen of the catheter 200, all before insertion into the patient. The pre-assembled components can be simultaneously inserted into the sheath 400 and advanced together through and beyond the turns of the carotid siphon.

[0151] The optimal relative lengthening of the catheter 200 and the catheter delivery element 300 can additionally be determined based on the staggering of the material transitions. Fig. Figure 11 is a schematic representation illustrating the approximate locations of the material transitions in the catheter delivery element 300 and the approximate locations of the material transitions in the catheter 200. For example, the catheter delivery element 300 may include a proximal section 366, which may be a hypotube and has a material hardness of approximately 72D. The proximal section 366 transitions at location 1101a to a region having a material hardness of approximately 55D, which transitions at location 1101b to a region with a material hardness of approximately 35D, and which transitions at location 1101e to a region with a material hardness of 35D. Similarly, the catheter 200 may include a proximal control element 230, which is a stainless steel band.The proximal control element 230 transitions at location 1103a to a region with a material hardness of 72D, at location 1103b to a region with a hardness of 55D, at location 1103c to a region with a material hardness of approximately 40D, at location 1103d to a region with a material hardness of approximately 35D, at location 1103e to a region with a material hardness of 25D, at location 1103f to a material hardness of approximately 85A, and at location 1103g to a material hardness of approximately 80A. A distal catheter delivery element 300 can be made of Tecothane with a material hardness of approximately 62A. Positions 1101 of the catheter delivery element 300 and 1103 of the catheter 200 may be offset, such that the positions are offset from each other. There may be more or fewer material changes within the catheter delivery element and the catheter.

[0152] The catheter 200 and the catheter delivery element 300 can be pre-assembled during manufacturing such that the catheter delivery element 300 extends to an optimal length distal to the distal end of the catheter 200 and / or the material transitions are staggered. An optimal extension length can be such that the entire length of the tapered distal tip of the catheter delivery element 300 extends beyond the distal end of the catheter 200, so that the outer diameter of the catheter delivery element 300, at which the at least one contact point is located, is aligned with the distal end of the catheter 200 in such a way that it essentially coincides with it.This can result in the tightly fitting outer diameter region of the elongated body 360 being essentially aligned with the distal end of the catheter 200, such that it remains within the lumen of the catheter 200, with only the tapered region of the distal tip 346 extending distal to the lumen of the catheter 200. This relative arrangement provides the best configuration for advancement through tortuous vessels, where a lip at the distal end of the system would present the greatest difficulty. This optimal pre-assembled configuration can be maintained by a coupler configured to engage both the proximal control element 230 of the catheter 200 and the proximal section 366 of the catheter advance element 300. The coupler can be used during a procedure. Alternatively, the coupler can be removed prior to a procedure.

[0153] Different areas of the distal lumen section 222 and the elongated body 360 of the catheter delivery element 300 can exhibit different bending forces. The bending force in N-mm² can be measured by evaluating the force in Newtons (N) generated when the device is deflected a certain distance using a specific gauge length. Fig. Figure 12 is a schematic representation of a test system 1205 for evaluating the bending force or flexural strength of the various components described herein. The test system 1205 can vary, as is known in the art. The one in Fig. The test system shown in Figure 12 includes a pin 1210, which forms a fixed point, and an anvil 1215, which is connected via a lever 1222 to a strain gauge 1220, which forms a measuring point. The pin 1210 can hold the sample 1201 under test such that a gauge length 1225 of the sample 1201 is exposed. The anvil 1215 is connected to the strain gauge 1220 via the lever 1222 and can be pressed against a section of the sample 1201 that is positioned a distance of the gauge length 1225 from the pin 1210. The anvil 1215 can displace this section so that the section acts as a trigger for a force that can be measured by the strain gauge 1220. The gauge length 1225 can be approximately 5 mm. The anvil 1215, for example, can have a width of approximately 2 mm, resulting in a minimum measuring length of approximately 3 mm. The length may vary depending on the testing system.

[0154] The bending force (modulus of elasticity x area moment of inertia) can be calculated according to the equation EI = FL3 / 38, where F is the deflection force, L is the gauge length, and 8 is the deflection. For example, with a gauge length of 3 mm (L = 3 mm) and a deflection of the catheter tip by 2 mm (8 = 2 mm), a force of 0.05 to 0.5 N can be generated. In some implementations, the bending force at the most distal end of the distal lumen section can range between 0.225 and 2.25 N-mm². For comparison, the flexibility of the catheter delivery element 300, based on similar deflection measurements and calculations, can be as follows. With a deflection of 2 mm and a force measurement length of 3 mm, the distal tip of the catheter delivery element 300 can exhibit a bending force between 0.005 and 0.05 N or a bending force between 0.0225 and 0.225 N-mm2.Other procedural catheters described herein may exhibit similar flexibility zones that provide variable relative stiffness, changing from the proximal end to the distal end of the catheter, as described elsewhere herein.

[0155] Fig. Figures 13A-13B schematically illustrate points along the catheter system that correspond to the one described in Fig. The test system shown in Figure 12 can be used. The points may vary depending on the overall size of the catheter system. The various points of the catheter system 150 can be tested when the catheter system 150 is placed in a feeder configuration. The catheter 200 may have a lumen and a distal end with an opening from the lumen 223. The lumen may have an inner diameter of at least approximately 0.052 inches at the distal end. The tubular section 360 of the catheter feeder element 300 may have an outer diameter with at least one contact point, the difference between the inner diameter and the outer diameter at the contact point being no more than approximately 0.010 inches. The at least one contact point may be the location on the catheter feeder element 300 immediately proximal to the tapered distal tip 346.When the catheter advance element 300 is in the advance configuration and positioned coaxially within the lumen of the distal lumen section 222 of the catheter 200, the at least one contact point of the tubular section 360 can be substantially aligned with the distal end of the catheter 200. In this configuration, the distal section 346 of the catheter advance element 300 extends distally to the distal end of the catheter 200. In some implementations, the difference at the contact point is no more than about 0.010 inches or lies between about 0.006 inches and 0.008 inches.

[0156] The tubular section 360 of the catheter delivery element 300 may have a radiopaque marker band embedded in or positioned above a wall of the tubular section 360 near the distal end. A first radiopaque marker band 344a is located at the distal end of the tapered tip section 346, and a second radiopaque marker band 344b is located at the proximal end of the tapered tip section 346. The proximal radiopaque marker band 344b may have a proximal edge, a distal edge, and a width between the proximal and distal edges. In the advancement configuration, the proximal edge of the radiopaque marker band 344b can be substantially aligned with the distal end of the distal catheter segment 222, such that the radiopaque marker band 344b remains outside the lumen 223 of the distal catheter segment 222.At least one section of the radiopaque marker band 344b can be positioned at the abutment point or location of the catheter delivery element 300 where the outer diameter is no more than about 0.010 in, preferably between about 0.006 in and 0.008 in smaller than the inner diameter of the catheter 200 in which it is positioned. The at least one abutment point of the tubular section 360 can be located proximal to the tip section 346 and be situated where the taper of the tip section 346 substantially terminates. This allows the tapered tip section 346 to fully extend outside the distal end of the catheter 200 and the alignment of the nib point essentially within the distal opening of the lumen 223 of the distal catheter section 222, thereby minimizing any distal lip that could be formed by the catheter 200.The point of contact can be located along at least one section of the length of the outer diameter of the tubular section 360, which has a length of at least about 5 cm to about 10 cm, wherein the outer diameter is substantially uniform or non-uniform.

[0157] The top section 346 can include at least three points (see e.g. P1, P2, P3 in the Fig. 13A-13B) that are spaced apart along the length of the tip section. The distal point P1 of the at least three points can be located at a distance proximal to the most distal end of the catheter delivery element 300. This distance can be a minimum distance required to establish a measurement length for the test system, for example, at least approximately 3 mm to approximately 5 mm. An intermediate point P2 of the at least three points can be located at a distance proximal to the distal point P1. A proximal point P3 of the at least three points can be located at a distance proximal to the intermediate point P2. Additional points can be measured on the tapered tip section 346 and are provided for illustration.

[0158] Fig. Figure 13A also illustrates points that can be tested on the system 150 as a whole. The coaxial catheter system 150 in the delivery configuration can include at least two system points along a length of the coaxial system 150. A first system point S1 of the at least two system points can be located proximal to the distal end of the catheter 200. The first system point S1 generally takes into account the combined bending force of the catheter 200 and the bending force of the catheter delivery element 300, which extends through the catheter 200 (see dashed line in Figure 13A). Fig. 13B). The first system point S1 can be located proximal to the distal end of the catheter 200 by a measuring length of approximately 5 mm. A second system point S2, of which there are at least two system points, can be located distal to the first system point S1, for example, at a distance of at least approximately 1 mm distal to the distal end of the catheter segment. The second system point S2 can take into account the bending force of the catheter delivery element 300, which extends outside the catheter 200. The second system point S2 is located in Fig. Point 13A is illustrated as a point distinct from P3; however, the second system point S2 could be the same as the proximal section P3 or the same as another point, for example, P4. The points are provided for illustrative purposes only and are not intended to be restrictive. Other points are also considered here.

[0159] Fig. Figure 13B illustrates theoretical bending forces (N) of a catheter system 150 at various points along the length of the system 150. The at least three points on the tip section 346 include P1, P2, P3, and also P4, which are spaced apart along the length of the tip section 346 of the catheter delivery element 300 (represented by a dashed line). Each of these points can be located distal to the distal end of the catheter 200 (solid line) in the delivery configuration and thus only considers the bending force of the catheter delivery element 300. A fifth point P5 along the length of the catheter delivery element 300 is also shown in Figure 13B. Fig. 13B is shown and can be positioned at a point within the catheter 200 when the system 150 is in the feed configuration. However, P5 only considers the bending force measurement of the catheter feed element 300.

[0160] The catheter 200 and the catheter delivery element 300 can each have a plurality of material changes from the distal end to the proximal end, such that when the catheter delivery element 300 is positioned coaxially inside the catheter 200 in the delivery configuration, the flexibility of the system 150 changes linearly from the flexibility of the distal tip of the catheter delivery element 300 to the more proximal regions of the system 150. In other words, the change in flexibility from the distal tip 346 of the catheter delivery element 300 (which is positioned outside the distal end of the catheter 200 while in the delivery configuration) to the flexibility of the system 150 as a whole (i.e., catheter delivery element 300 plus catheter 200) can be defined by a slope that does not include a significant jump and is essentially constant.

[00207] Fig. Figure 13B illustrates this additive stiffness of the system 150 moving proximally along a length of the system 150. Fig. Figure 13B shows that the distal end of the catheter delivery element 300 at P1 exhibits a bending force that is significantly less than the bending force of the distal end of the catheter 200 through which it extends (e.g., greater than at least approximately twice as much). In some implementations, the bending force of the distal end of the catheter delivery element 300 at P1 is no more than approximately 0.05 N. The bending force of the catheter delivery element 300 can increase along the length of the distal tip section 346 to approximate the higher bending force of the distal end of the catheter 200. For example, the stiffness of the distal tip section 346 can increase by at least a factor of two along its length to approximate the higher bending force of the distal end of the catheter 200. The bending force of the catheter system 150 along its length can generally have a constant slope.This generally constant slope of the increased bending force for the distal section of the catheter delivery element 300 (in . Fig. 13B shown as a dashed line) can be converted into a generally constant slope of the increased bending force for the combined system 150 (in Fig. 13B (shown as a dashed line) such that there is no significant change or increase in slope between the two. The bending force of the distal section 346 can have a constant slope until it changes the constant slope of the system 150 as a whole (i.e., additive bending force between catheter 200 and catheter delivery element 300, shown by a dashed line). The bending force of the catheter delivery element 300 can continue to increase along the length of the tip section 346 (e.g., from P1 to P2 to P3 to P4) and then decrease again, for example, proximal to the at least one contact point (see, for example, P5 in ). Fig. 13B). The bending force of the catheter delivery element 300 can be reduced proximal to this flexion point and remain significantly lower than the bending force of the catheter 200 over a length. In some implementations, a proximal marker 344b, indicating the proximal end of the tapered distal tip 346 of the catheter delivery element 300, can indicate the stiffness of the catheter delivery element 300 at this point (e.g., near P3, P4, S2 in Fig. 13B) locally increase. This minimizes the increase in stiffness from the distal tip section 346 of the catheter delivery element 300 to the distal end of the catheter 200 of the assembled assembly 150. Tables 1, 3, 4, and 5 of Example 1 in the "Experiments" section below describe the bending forces at various points along a length of different catheter systems.

[0161] The bending forces along the length of the catheter system 150 can be used to calculate the slopes of different segments of the system 150. A difference between the bending force at P2 and the bending force at P1, divided by the distance between P2 and P1, and / or a difference between the bending force at P3 and the bending force at P2, divided by the distance between P3 and P2, can provide a first flexibility slope. A difference between the bending force at P3 and the bending force at P2, divided by the distance between P3 and P2, can provide a second flexibility slope. An average of the first and second flexibility slopes can define an average flexibility slope of the tip section.In some implementations, a fourth distal tip point can be measured in such a way that the average flexibility slope of the tip segment can include this additional segment when calculating the average slope (e.g., the segment between P3 and P4). The difference between the bending force at S1 and the bending force at S2 (whether P3 or P4), divided by the distance between S1 and S2 (whether P3 or P4), can provide an initial system flexibility slope.

[0162] In some implementations, the bending force of the distal end of the catheter delivery element 300 may not exceed approximately 0.05 N. The average flexibility slope of the tip section may be at least approximately 0.005 N / mm. The system flexibility slope may range between approximately 0.01 N / mm and approximately 0.03 N / mm. The ratio between the system flexibility slope and the average flexibility slope of the tip section may be less than approximately 25, less than approximately 15, and preferably less than approximately 5, such as 3 to approximately 1. The slopes may be substantially constant or nearly constant and may exhibit substantially no stepwise increases in the bending force slope from one segment to the next along the length of the catheter system 150.In particular, the catheter systems described herein avoid large abrupt increases in the slope between the flexibility of the section extending distal to the distal end of the catheter and the flexibility of the system as a whole (see also the examples described below in Example 1). Fig. 14A-14D).

[0163] The bending force of the distal tip of the catheter delivery element 300 at P1 can be a fraction of the bending forces of the distal end of the catheter 200, such as between 5% and 15%. In contrast, the bending force of the contact point on the catheter delivery element 300 near the proximal end of the distal tip 346 (e.g., P3 or P4 or S2) can be approximately 50% to 90% of the bending force (or flexibility) of the distal end of the catheter 200. Thus, the bending force at the contact point of the catheter delivery element 300 can be closer to the bending force of the distal end of the catheter 200. In some implementations, a section of the catheter advance element 300, which is proximal to the tapered distal tip 346, may have a length of about 5 cm to about 10 cm, and this section may have a bending force (or flexibility) that may be about 40% to 90% of the bending force of the distal end of the catheter 200.

[0164] The smooth transition of flexibility along the length of the catheter systems described herein provides optimal maneuverability without risk of kinking. The catheter systems described herein can have a distal end that is exceptionally flexible and transition to a proximal end that is exceptionally stiff to ensure optimal torque transmission and handling. Thus, the bending force P1 of the catheter delivery element 300 can be a fraction of the bending force of a portion of the proximal section 366 of the catheter delivery element 300. The proximal section 366 can include at least one stiffness point located within approximately 20 cm proximal to the tubular section 360. The stiffness point can exhibit a relatively high bending force, for example, between approximately 5 N and approximately 15 N.The ratio of the bending force at the at least one stiffness point to the first bending force of P1 can be at least approximately 100, at least approximately 200, or at least approximately 300. The proximal section 366 of the catheter delivery element 300 can be more than 300 times stiffer than the distal tip P1 of the catheter delivery element at P1. The bending force of the catheter delivery element 300 at the distal tip P1 cannot exceed approximately 0.30% of the bending force of the proximal section 366, for example, between 0.10% and approximately 0.50%. Application procedure

[0165] In a Fig. In the implementation shown in Figure 15, a guide sheath 400 can be deployed such that the distal end of the sheath 400 is advanced, for example, to a point in the internal carotid artery (ICA). The sheath 400 can be advanced to the carotid artery using a guidewire and an advancement tool. The guidewire and advancement tool, if used, can be removed or replaced with a smaller guidewire that can be advanced further distally into the cerebral vessels, or without a guidewire altogether, as described in more detail below. A first catheter 200a can be advanced through the working lumen of the guide sheath 400 and from its distal end. The first catheter 200a can have a distal lumen segment 222a that is connected to a proximal control element 230a.The proximal control element 230a can have a smaller outer diameter than the outer diameter of the distal lumen segment 222a and can be connected to the lumen of the distal lumen segment 222a near a proximal opening. The first catheter 200a can be advanced using a catheter advancer element and without the aid of a guidewire. The catheter advancer element can assist the advancement of the first catheter 200a through the vessel without it becoming stuck at a sharp bend and / or vessel bifurcation. The first catheter 200a can be advanced through the working lumen of the guide sheath 400 and then through the vessel to a first target site. The catheter advancer element 300 can be removed from the lumen of the first catheter 200a. A second catheter 200b with a second catheter advancer element 300 can be advanced through the lumen of the first catheter 200a.The second catheter 200b can also include a distal lumen segment 222b, which is connected to a proximal control element 230b near a proximal opening from the lumen of the distal lumen segment 222b. Similar to the first catheter 200a, the proximal control element 230b of the second catheter 200b can have a smaller outer diameter than the outer diameter of the distal lumen segment 222b. The distal end of the second catheter 200b can be extended using its proximal control element 230b so that it extends beyond the distal end of the first catheter 200a, allowing the smaller-diameter second catheter 200b to target a site on a distal vessel with a narrower dimension than the site of the first catheter 200a. In this implementation, the first catheter 200a with spikes can serve as a carrier for the second catheter 200b with spikes.The second catheter 200b can be advanced with or without a catheter guidewire. After removal of the second catheter advance element 300, the inner lumen of the second catheter 200b can be in fluid communication with the inner lumen of the first catheter 200a, which is in fluid communication with the working lumen of the guide sheath 400, thus forming a continuous lumen consisting of three sections with progressively larger dimensions toward the proximal end of the catheter system. For example, the first catheter 200a can have a distal lumen section 222a with an inner diameter of approximately 0.088 inches, and the second catheter 200b can have a distal lumen section 222b with an inner diameter of approximately 0.070 inches. More than two nested catheters are considered, the respective inner and outer diameters of which are dimensioned to accommodate each other and be used together.The corresponding inner and outer diameters of the catheters can be dimensioned so that they slide relative to each other, yet still provide a sufficient seal. For example, the interconnected lumens created by the nested arrangement can seal against each other, allowing aspiration and enabling the application of suitable pressure through the nested catheters to achieve, for example, a suction force sufficient for the aspiration embolectomy of removed clots.

[0166] The proximal end of the nested catheter system can have various gripping, organizing, and securing features. For example, the guide sheath 400 can enclose a proximal end connected to a rotating hemostatic valve 434, which provides access to the working lumen through which the catheters can be advanced. Each component of the catheter system can extend proximally from the valve 434. For example, the proximal control elements 230a, 230b of the catheters 200a, 200b can extend through the valve 434. Proximal extensions of their respective catheter delivery elements (in Fig. (15 not shown) may also extend proximally through the valve 434. Each of these components in the nested or telescoping catheter set may have identifying features at their proximal end regions that distinguish them from one another. For example, each proximal control element 230a, 230b may have a tab 234a, 234b with a distinguishable shape, color, or other visual features unique to that particular catheter. Each proximal control element 230a, 230b may include a coupling feature, such as a clamp or other connector, that organizes the various control elements and helps prevent entanglement. Nested catheters and their respective catheter delivery elements may be included in a kit.

[0167] The systems described herein involve the use of a base sheath and a catheter that can pass through the sheath and is long enough to reach the intracerebral target, such as the Ml segment of the middle cerebral artery. The use of an introducer or catheter advancer with a tapered tip allows for the insertion of large-diameter catheters, such as full-length catheters "over the wire" or catheters like those described herein, which have a proximal extension. The catheter advancer may include a pair of radiopaque markers configured to assist the operator in advancing the system.The distal marker near the most distal end of the catheter delivery element can be distinguished from the distal marker on the catheter by its characteristic appearance under fluoroscopy, as well as by simply moving the atraumatic catheter delivery element back and forth to understand its relationship and positioning relative to the catheter. The second marker on the catheter delivery element, located proximal to the most distal tip marker, can delineate the tapering of the distal tip, i.e., the area where the outer diameter of the catheter delivery element is sufficiently large to reduce the "lip" of the transition between the catheter delivery element and the catheter through which it is inserted and configured for delivery.The markings help in positioning the catheter delivery element relative to the distal end of the large-diameter catheter, so that the tip of the catheter is aligned with the taper of the catheter delivery element and optimal alignment is facilitated.

[0168] The relationship between the distal marker of the large-diameter catheter and the tapered marker of the catheter advancer (i.e., the proximal marker indicating the start of the taper) is identifiable using the tandem marking system. The paired elements are in a "tip-to-taper" position. The relative length between the catheter advancer and the catheter can be set during introduction of the system into the right hand-held catheter (RHV). However, the relative length may change as the system advances through the sheath or guide catheter. As the system exits the guide catheter, the large-lumen catheter and catheter advancer can be adjusted to assume the tip-to-taper position as the system traverses the often tortuous proximal vessel (e.g., the cervical internal carotid artery) toward more distal targets.The system, consisting of the large-diameter catheter and the catheter delivery element, can be locked in its relative extension, thus maintaining the alignment of the delivery element and the large-diameter catheter. Since the large-diameter catheter is visible within the distal end of the sheath or even slightly beyond it, the delivery element can be adjusted to assume the correct position relative to the catheter before advancing. The optimal relative extension between the distal marker of the catheter and the conical marker on the delivery element can be maintained over as much of the anatomy as possible to maximize the delivery capability of the delivery element, navigating twists and turns while avoiding side branches such as the ophthalmic artery.Once the target is reached, the catheter delivery element is fixed and the large-bore catheter is then advanced over the catheter delivery element towards the target without crossing the target.

[0169] The catheter advancer is specifically designed to allow catheter insertion without a guidewire. This ability to insert the catheter without crossing the embolus and without a guidewire is based on the smooth transitions between the outer diameter of the advancer and the large-bore catheter, as well as the smooth transitions in flexibility between the two. When the advancer is bent into an arc greater than 180 degrees, its softness and flexibility create a smooth arc without sharp bends or kinks in the catheter's geometry. Thus, the advancer seeks out larger lumens and reaches the areas where the majority of blood flow is concentrated, as opposed to smaller arteries. The distal tip of the advancer can further promote a strong preference for seeking out larger vessels during advancement into the distal vessels.This tendency to remain within the main channel allows for the advancement of large-diameter catheters without the aid of a catheter guidewire. The tendency to follow the main channels of blood flow is consistent with the pathophysiology of acute ischemic stroke, in which larger emboli tend to follow the same pathways until they become lodged and interrupt antegrade blood flow. Furthermore, these main channels are often ideal for the placement of access catheters, as these conducting arteries allow smaller catheters to be inserted into specific target arteries for therapeutic interventions.

[0170] Standard neurovascular procedures and nearly all endovascular procedures rely on the concept of a guidewire directing a catheter to a target site. Guidewires are typically pre-shaped and often encounter side branches from non-target locations, where the guidewire can become entangled or slip, leading to time-consuming disruptions during the procedure that often require the surgeon to repeatedly realign the guidewire. Furthermore, this tendency of a guidewire to penetrate side branches can be dangerous. Guidewires in neuroanatomy are typically 0.014 to 0.018 inches in diameter and are often capable of encountering and traumatizing small branches that can accommodate this size, potentially resulting in minor hemorrhages, dissections, or occlusions. In a delicate area like the brain, these events can have catastrophic consequences.The tendency of a guide wire to become entangled and slipped can also lead to the formation of a leading edge on the guide wire, which can move forward independently or as part of a triaxial system to create dissection surfaces and traumatize small vessels.

[0171] In contrast, the catheter delivery element described herein preferentially remains within the larger lumen of a vessel. In stroke treatment, an embolus is propelled to specific anatomical structures by the blood flow generated by the arterial system within the cerebral anatomy. The catheter delivery element tends to follow a path identical to that taken by an embolus, particularly one originating from a site such as the heart or carotid artery. Even in highly tortuous anatomy and with many bends, the catheter delivery element positions itself within the largest lumen of the anatomy. The catheter delivery element can preferentially take the larger lumen at a bifurcation while simultaneously following the greatest blood flow, thereby maintaining the overall direction and angles of the vessel.

[0172] Considering the standard anatomy of the cerebral vascular system, the Circle of Willis is supplied by two vertebral and two carotid arteries. Since these four arteries are the access points to the cerebral anatomy, the course of the catheter advancement element can be identified and has been validated in standard models of cerebral anatomy. In the anterior circulation, where the entry point for endovascular interventions in the brain is the internal carotid artery (ICA), the catheter advancement element can guide the large-diameter catheter to the M1 segment of the middle cerebral artery (MCA). The high flexibility of the catheter advancement element, combined with the distal flexibility of most cerebral catheters, allows for guidance even in cases of significant tortuosity.Regardless of the tortuosity of the arterial course, the catheter advancer tends to navigate the bends and deliver the largest branch of a main artery, for example, from the ICA to the M1 segment of the MCA. The branching at the M1-to-M2 level can be variable, but often has two main branches (superior and inferior) that may branch evenly or unevenly, depending on the anatomy, which can vary considerably from patient to patient. If the diameter and angulation of the M2 branch are similar, the catheter advancer can take either of the two branches. If the target for catheter placement does not have a favorable arterial angulation or size, the catheter advancer may need to be bent (e.g., by forming a malleable distal tip) and aligned, or a guidewire may be used.

[0173] In some anatomies where the M2 bifurcation is of an even size, a back-and-forth motion can help select one branch and then the other without the need for a guidewire or a curved distal tip of the catheter advancer. The back-and-forth motion guides the catheter advancer into one of the two branches of the M2. Even if initially straight, the catheter advancer will acquire a degree of curvature that aids in its guidance into the vessel. Therefore, if an operator encounters an M2 bifurcation and wishes to cannulate one of the two branches of an evenly divided bifurcation, selecting either branch with the catheter advancer is possible without a catheter guidewire.

[0174] Thus, major channels such as the ICA, the middle cerebral artery, and its tributaries in the anterior circulation are naturally the preferred route for the described catheter advancement element and the subsequent insertion of a large-diameter catheter (via access from the ICA). A similar phenomenon can occur in the posterior circulation, which has access via the vertebral arteries originating from the right and left subclavian arteries. The catheter advancement element also utilizes the major channels in this circulation by traversing the vertebral arteries leading to the basilar artery and its main tributaries: the posterior cerebellar artery and the superior cerebellar artery in the posterior circulation.

[0175] Navigation using the catheter advancement element can ensure maximum deliverability with minimal vascular trauma. Catheters can cause a "razor blade effect" in a curved vessel because the blunt end of a large-diameter catheter tends to follow the greater curvature of the vessel as it is advanced by the operator. This blunt-ended catheter system can hollow out or "shave" the greater curvature with its sharp edge, increasing the risk of dissection along an anatomical plane within the multilayered medium or large artery or vein (see, e.g., Catheter Cardiovasc. Interv. 2014 Feb; 83(2):211-20). Placing a partially inflated balloon and a catheter guidewire through the catheter can mitigate this "razor blade effect" in this situation by beveling the edge of the large-bore catheter.Similarly, the catheter advancement element can serve to minimize the edge of these catheters. By positioning the catheter advancement element within the lumen of the large-bore catheter, such that the tapered marker of the advancement element is optimally aligned with the distal marker of the catheter, the edge is minimized, thus eliminating the "razor blade effect" when the large-bore catheter is advanced through the turns of the vessel. This is particularly useful in cerebral anatomy. Stroke treatments are typically required in areas distal to the carotid siphon, especially distal to the origin of the ophthalmic artery from the larger curve of the strong tortuosity of the last turn of the carotid siphon, the "S-turn," the "anterior genu" of the carotid siphon, which is typically considered part of the terminal internal carotid artery (ICA).The specific design of the catheter advancement element, when correctly oriented within the large-diameter catheter (note that the distal tip marking indicates the "tip-to-taper" position) relative to the taper marking of the advancement element, maximizes the likelihood of avoiding puncture and snagging on the ocular artery. The tapered marking of the advancement element can be positioned at or behind the origin of the ocular artery to minimize these adverse effects and allow the large-bore catheter to pass through the artery without incident. In a relatively straight section, such as is often found after passing the siphon, the large-bore catheter can be advanced over the advancement element, which continues to act as a guide to the target.The transition between the catheter advancer and the distal edge of the large-bore catheter is insignificant, especially compared to the step changes that occur with a typical microcatheter or guidewire, which do not prevent entanglement on branches such as the ocular artery. The catheter advancer allows the large-bore catheter to be maneuvered to the surface of the embolus without the need for a microcatheter or catheter guidewire and without crossing and / or fragmenting the embolus in any way.

[0176] Conventional techniques for treating acute ischemic occlusion (AIS), whether using a stent retriever, aspiration techniques, or a combination of both, require crossing the target occlusion with a guidewire and a microcatheter. Crossing the embolus with a guidewire and subsequently a microcatheter can lead to fragmentation of the occlusion, which may be fragile and thrombotic. Therefore, an aspiration technique is advantageous, as it completely removes the embolus without crossing the occlusion with a device.

[0177] A stent retriever cannot cross or intervene at the target occlusion without being pulled off by the embolus. ADAPT is a best-in-class, aspiration-only technique that avoids crossing the target occlusion with a stent retriever, thus reducing the risk of fragmentation. However, the ADAPT approach still requires crossing the target occlusion with both a guidewire and a microcatheter (see Turk et al. J Neurointerv. Surg. 2014 Apr 1; ​​6(3):231-7). A guidewire such as Neuron Max (Penumbra) is positioned as distally as possible. A microcatheter and microguidewire are advanced through the guidewire and distally to the occlusion. Using the microcatheter and microguidewire as a carrier, a reperfusion catheter such as Penumbra 5 Max is advanced until occlusion.Aspiration is maintained until the occlusion at the tip of the reperfusion catheter becomes lodged or wedged. The reperfusion catheter is then withdrawn and removed while maintaining aspiration and occlusion at the catheter tip.

[0178] The systems described herein do not require a guidewire or microcatheter. And if a guidewire and microcatheter are used, they do not need to be advanced to the target occlusion. Thus, the systems described herein can incorporate catheters of relatively large diameter that can be positioned without compromising the target occlusion, thereby reducing the risk of stroke and subsequent effects from occlusion fragmentation and demonstrating efficiency. Furthermore, the systems described herein are single-operator systems, allowing the operator to work on a single recurrent venous access device (RHV) and, in the case of supported components, to manipulate all elements used for navigation within the anatomy with one hand by "squeezing" them together. This is sometimes referred to as "one-point operation."

[0179] As described above, the catheter delivery element can be arranged coaxially within the single lumen of the distal catheter segment, forming a coaxial catheter system. The catheter can have a distal catheter segment and a proximal extension. The distal catheter segment can have an inner diameter defining the single lumen and a distal end defining a distal opening from the lumen. The proximal extension can be connected to the distal catheter segment and extend proximal to it. The catheter delivery element can have a tubular polymer segment with an inner diameter defining a lumen, a first outer diameter that is substantially uniform along its length, and a radiopaque marker band embedded in or positioned above a wall of the tubular polymer segment.The radiopaque marker band can form a second outer diameter, positioned distal to and larger than the first. A tapered polymer tip can be positioned distal to the second outer diameter and terminate at a distal opening of the tubular segment's lumen. The conical polymer tip can be between approximately 0.5 cm and 4 cm in length, for example, between approximately 1 cm and 3 cm, or approximately 2.5 cm. The catheter delivery element can also include a proximal extension connected to and extending proximal to the tubular polymer segment.

[0180] The coaxial catheter system can have a delivery configuration in which the conical polymer tip of the catheter delivery element extends distally to the distal end of the distal catheter segment, and the radiopaque marker band is essentially aligned with the distal end of the distal catheter segment, and the first outer diameter is positioned within the lumen of the distal catheter segment.

[0181] The operator can manipulate both the catheter and the catheter delivery element from a single radiofrequency handpiece (RFH) of the guide sheath. The coaxial catheter system can be advanced together, maintaining the delivery configuration. The relative relationship between the radiopaque marker band on the catheter delivery element and a second marker band near the distal end of the catheter helps maintain the delivery configuration during delivery. The operator can use a single hand movement to position the two elements relative to each other and advance this coaxial catheter system.

[0182] The coaxial catheter system can be advanced as far distally as possible until the catheter advancer is positioned at the surface of the embolus. The proximal extension of the catheter advancer can be held "fixed" to the RHV, and the catheter can be advanced over the catheter advancer so that the distal end of the distal catheter segment is advanced over the catheter advancer to the surface of the embolus. No catheter guidewire or microcatheter is required to advance the coaxial catheter system to the surface of the embolus. Importantly, no devices need to cross the embolus.

[0183] The catheter advance element can then be withdrawn from the coaxial catheter system and removed from the single RHV while the catheter is held in position at the surface of the embolus. The system is ready for the commencement of aspiration, as described in more detail below.

[00232] In some implementations, the first coaxial catheter system may not be able to reach the surface of the embolus. Therefore, the catheter advance element of the coaxial catheter system can be removed, leaving the lumen of the distal catheter segment open to advance a second coaxial catheter system through the first catheter. The second coaxial catheter system can include a second catheter and a second catheter advance element and is advanced similarly to the first coaxial catheter system (i.e., via single-point manipulations), but through the first catheter, which acts as a carrier.

[0184] Once the catheter is positioned at the surface of the embolus, the right hemorrhage (RHV) can be closed and aspiration initiated through the same RHV, for example, via a side arm. The embolus can then be aspirated from the body through the catheter using only the aspiration pressure. Alternatively, if the catheter has a blocked distal orifice, it can be slowly withdrawn, for example, towards the lumen of a larger-diameter catheter, while aspiration is applied to remove the embolus.

[0185] Retracting an embolus lodged at the distal orifice of the catheter to the distal orifice of the guide sheath can increase the risk of fragmentation and embolization, depending on how far it must be withdrawn before it is completely enclosed within a lumen. Therefore, it is desirable to use a nested system of successively larger catheter sizes to create a family of aspiration catheters, all operating from a single point of entry via the single right ventricular hemorrhage (RHV). This allows the smallest-diameter catheter, advanced most distally, to be withdrawn only a short distance into a larger-diameter catheter, which can then completely aspirate the embolus, or, if necessary, a further short distance into an even larger-diameter catheter, which can aspirate the embolus from the body.This reduces the likelihood of fragmentation of the captured clot and increases the likelihood of complete clot removal.

[0186] The guide sheath can be a large 7F sheath configured to accommodate a larger-diameter catheter with an inner diameter of approximately 0.088 inches, which in turn can accommodate a medium-diameter catheter with an inner diameter of approximately 0.070 inches, which in turn can accommodate a smaller-diameter catheter with an inner diameter of approximately 0.054 inches. Various sizes are considered here, and these examples are not intended to be limiting.

[0187] Although the larger-diameter catheter can aspirate the embolus more efficiently, its significantly larger dimensions may prevent it from advancing to the embolus without additional manipulation. In some implementations, a smaller-diameter catheter, extending through the lumen of the larger-diameter catheter, can be advanced to the surface of the embolus. The smaller-diameter catheter (and its delivery element) can be fixed in such a way that the larger-diameter catheter is advanced as far distally as possible over the smaller-diameter catheter.If the larger-diameter catheter, advanced over the smaller-diameter catheter, can reach the embolus in this manner, the catheter advancer can be removed from the smaller-diameter catheter, the RHV (respiratory hemorrhage) can be closed, and aspiration can begin. Both the distal end of the smaller-diameter catheter and the distal end of the larger-diameter catheter are positioned at the surface of the embolus. The smaller-diameter catheter can be withdrawn from the system while aspiration continues. If free flow is established with aspiration (e.g.,(recognizable by the flow into the aspiration source), the operator can position the larger-diameter catheter and consider whether to perform angiography to confirm the restoration of antegrade flow and the removal of the obstruction, after ensuring that the large-diameter catheter is completely clear of debris through aggressive aspiration and flushing. If free flow cannot be established, aspiration can continue, and after removal of the smaller-diameter catheter, the larger-diameter catheter can be removed, thus clearing the embolus from the body. The higher flow and forces generated by the larger-diameter catheter under full aspiration, without the smaller-diameter catheter positioned in its lumen and obstructing flow, are achieved.During the removal of both the smaller diameter catheter and the larger diameter catheter, a single, common source and a single, common aspiration source can be used.

[0188] If the larger-diameter catheter cannot reach the target embolus by crawling over the smaller-diameter catheter, the larger-diameter catheter and the catheter delivery element for the smaller-diameter catheter can be fixed to the RHV (Reference Handling Unit) such that the smaller-diameter catheter can be advanced between them to the surface of the embolus. The smaller-diameter catheter can then provide a guide for a further attempt to advance the larger-diameter catheter toward the surface of the embolus.These steps can be repeated in sequence to “advance” the larger diameter catheter toward the embolus until both the distal end of the smaller diameter catheter and the distal end of the larger diameter catheter are positioned near the surface of the embolus, allowing an aspiration embolectomy to be performed through it.

[0189] The smaller-diameter catheter can be attached to the embolus and retracted towards the larger-diameter catheter. If the embolus is too large to fully enter the lumen of the smaller-diameter catheter, it can be engulfed or retracted by the larger-diameter catheter. The smaller-diameter catheter, which has the embolus attached at its distal end by aspiration, can be withdrawn, whereupon the embolus can be immediately aspirated and retracted by the larger-diameter catheter.

[0190] Tension can accumulate in a catheter system being advanced through tortuous brain anatomy. When the distal tip of the catheter encounters resistance, downward and lateral forces can be exerted on the supporting catheter system. The entire system may move forward as the distal tip of the catheter passes these points of resistance. The resistance may be due to the twist in the vessel, obstructions or bifurcations, pre-existing implants, or other causes. Typically, the tension is accumulated without loss of position. The resulting effect is a back-and-forth movement of the system toward the target and the uniform accumulation of tension in the guide sheath as it is relentlessly forced downward (i.e., proximally backward against the direction of insertion).

[0191] In the case of stroke aspiration systems, the same stored tension can occur when advancing a larger-diameter catheter (e.g., one with an inner diameter of 0.088 inches). If the larger-diameter catheter develops stored tension and the operator attempts to advance it to the target embolus (e.g., in the Ml branch of the MCA), the larger-diameter catheter traverses the anatomy in a "larger curve to a larger curve," creating some loosening in the system. The stored tension creates resistance, causing the catheter to jam at some point and fail to reach the target. If the larger-diameter catheter does not target the embolus, a smaller-diameter catheter can be advanced to reach it, as it has a smaller diameter and better delivery.The smaller-diameter catheter can overcome the stored tension and traverse the anatomy in a "larger curve to a larger curve" motion, just as the larger-diameter catheter did. The smaller-diameter catheter can anchor itself to the embolus via the suction pressure applied by the system. The smaller-diameter catheter can be fixed at the site of occlusion, and aspiration can be turned on to maximum (e.g., via a pump). This will secure or anchor the smaller-diameter catheter to the embolus, allowing the operator to "straighten" the entire system and apply a proximally directed force to the smaller-diameter catheter to eliminate sagging relative to the surrounding anatomy, while the distal end of the smaller-diameter catheter remains anchored to the occlusion.Once the laxity is reduced, the catheters now traverse the anatomy in a "smaller curve to a smaller curve" rather than a "larger curve to a larger curve," thus straightening their path relative to the surrounding anatomy. A straightened path allows the larger-diameter catheter to be advanced over the anchored smaller-diameter catheter, so that its distal end reaches the embolic target in such a way that aspiration and anchoring by the smaller-diameter catheter are maintained. The surgeon creates a straighter, tension-free path to "push" the larger-diameter catheter over the smaller-diameter catheter.Once the larger diameter catheter is in place - even if the larger catheter does not reach the embolus - significant protection against embolism is provided and embolization outside the target area is avoided, especially if the larger diameter catheter is placed distal to the nearest bifurcation and proximal to the embolus site.

[0192] Once the larger-diameter catheter is positioned, the smaller catheter extending through it can be withdrawn. Aspiration can continue through the single source, and the seal around the encapsulated embolus is maintained as the smaller catheter is withdrawn toward the distal end of the larger-diameter catheter. Once the smaller-diameter catheter is retracted into the distal end of the larger-diameter catheter, aspiration pressure within the larger-diameter catheter can be automatically activated, allowing the embolus to be drawn into the lumen of the larger-diameter catheter. Due to the larger internal diameter, the embolus is likely to be removed under continuous aspiration pressure through the single, shared aspiration source.Both the smaller diameter catheter and the larger diameter catheter can be withdrawn from the system. materials

[0193] One or more components of the catheters described herein may include or consist of a variety of materials, including one or more of the following: metal, metal alloy, polymer, metal-polymer composite, ceramic, hydrophilic polymers, polyacrylamide, polyether, polyamides, polyethylene, polyurethanes, their copolymers, polyvinyl chloride (PVC), PEO, PEO-impregnated polyurethanes such as Hydrothane, Tecophilic polyurethane, Tecothane, PEO soft-segment polyurethane with Tecoflex, thermoplastic starch, PVP and combinations thereof and the like, or other suitable materials.

[0194] Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L and 316LV; mild steel; nickel-titanium alloys, such as linear-elastic and / or superelastic Nitinol; other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 like INCONEL® 625, UNS: N06022 like HASTELLOY® C-22®, UNS: N10276 like HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 like MONEL® 400, NICKELVAC® 400, NICORROS® 400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 like MP35-N® and the like), nickel-molybdenum alloys (e.g.,UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like); platinum-enriched stainless steel; titanium; combinations thereof; and the like; or any other suitable material as described elsewhere herein.

[0195] The inner lining materials of the catheters described herein may include low-friction polymers such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene), or PTFE with a polyurethane layer (Tecoflex). Reinforcing layer materials of the catheters described herein may be incorporated to provide mechanical integrity for the application of torque and / or to prevent flattening or kinking, such as metals, including stainless steel, nitinol, nitinol braid, spiral tape, spiral wire, cut stainless steel, or the like, or rigid polymers such as PEEK. Reinforcing fiber materials of the catheters described herein may include various high-strength polymers such as Kevlar, polyester, meta-para-aramid, PEEK, single fibers, multi-fiber bundles, high-tensile polymers, metals or alloys, and the like.The outer sheath materials of the catheters described herein can provide mechanical integrity and consist of a variety of materials such as polyethylene, polyurethane, PEBAX, nylon, Tecothane, and the like. Other coating materials of the catheters described herein include Paralene, Teflon, silicone, polyimide-polytetrafluoroethylene, and the like. EXAMPLES

[0196] The catheter systems described herein were developed using a system such as the one described in Fig. The 12 catheters shown were tested for bending forces, and the data are provided below. A first catheter system comprised a catheter feeder element having an outer diameter dimensioned to extend through a catheter with an inner diameter of approximately 0.054 inches (Version A). A second catheter system comprised a catheter feeder element having an outer diameter dimensioned to extend through a catheter with an inner diameter of approximately 0.070 inches (Versions B1 and B2). A third catheter system comprised a catheter feeder element having an outer diameter dimensioned to extend through a catheter with an inner diameter of approximately 0.088 inches (Version C).

[0197] At least three points along the tapered tip section of the catheter delivery elements were tested (see P1, P2, P3, P4 in the Fig. 13A-13B). The distal point P1 of the at least three points was located approximately 5 mm proximal to the most distal end of the catheter delivery element. The second point P2 of the distal tip section was an intermediate point of the at least three points located proximal to distal point P1. In version A, the second point P2 was located approximately 12 mm proximal to the most distal end of the catheter delivery element. In versions B1, B2, and C, the second point P2 was located approximately 20 mm proximal to the most distal end of the catheter delivery element. A proximal point P3 of the at least three points could be located proximal to the intermediate point P2 and was located approximately 13 mm proximal to the most distal end of the catheter delivery element in version A and approximately 25 mm proximal in versions B1, B2, and C. Some catheter system versions included a fourth point P4. P4 was designed for versions B1, B2 and Cat with approximately 27 mm, 27 mm respectively.Measured at 28 mm.

[0198] The catheter systems were placed in the feed configuration and soaked in a bath at 37 °C for a specific period prior to testing. The feed configuration for the experiment is as follows: the catheter feed element is positioned coaxially within the lumen of the distal catheter segment, such that the at least one contact point of the tubular segment is substantially aligned with the distal end of the catheter, and the distal tip of the catheter feed element extends distally to the distal end of the catheter. The region near P3 on the catheter feed element formed a contact point with the catheter, with the difference between the inner and outer diameters at the contact point not exceeding approximately 0.010 inches. The difference was approximately 0.006 inches for version A and approximately 0.008 inches for versions B1 and C.Each of the locations P1, P2, P3 and P4 (where applicable) was located at the tip section of the catheter delivery element and extended distally to the distal end of the catheter.

[0199] A fifth point P5 was measured for all versions that provided a bending force for the catheter delivery element only proximal to the contact point (see Fig. 1 3B). The fifth point, P5, was positioned at a location within the catheter when the system was in the advance configuration; however, P5 only considered the bending force measurement of the catheter advance element. In version A, this fifth point, P5, was measured approximately 16 mm proximal to the distal end of the catheter advance element. In versions B1 and C, the fifth point, P5, was located approximately 30 mm proximal to the distal end of the catheter advance element. When the components of the catheter system are in the advance configuration, this fifth point, P5, on the catheter advance element can lie within the catheter. Therefore, P5 was measured on the catheter advance element without the catheter being present.

[0200] At least two points along the catheter system were also tested to measure the bending force of the system in the delivery configuration (see S1 and S2 in the Fig. 13A-13B). The first system point S1 took into account the combined bending force of the catheter and the bending force of the catheter delivery element extending through the catheter, and is in Fig. 13B is represented by a dashed line. The first system point S1 of the at least two system points was located proximal to the distal end of the catheter at a measuring length of approximately 5 mm or approximately 19 mm from the distal end of the catheter system for version A and approximately 33 mm or 34 mm from the distal end of the catheter system for versions B1 / B2 and C.

[0201] A second system point S2, of which there were at least two system points, was located distal to the first system point S1. The second system point S2 accounted for the bending force of the catheter delivery element extending outside the catheter. In some tests, the second system point S2 was located distal to the distal end of the catheter and was identical to the proximal point P3 or the proximal point P4 (if present).

[0202] Table 1 below provides the bending forces, measured in Newtons (N), at various points along the length of the catheter systems in the advancement configuration. The points listed in the table generally correspond to those in the Fig. The points shown in Figures 13A-13B are not to scale. They are for illustrative purposes only, and other points can be measured.

[0203] Table 1 shows that the bending force at the distal end of the catheter delivery element at P1 was no more than approximately 0.05 N. The difference between the bending force at P2 and the bending force at P1, divided by the distance between P2 and P1, and / or the difference between the bending force at P3 and the bending force at P2, divided by the distance between P3 and P2, provided a first flexibility slope. The first flexibility slope was approximately 0.008 N / mm for version A, 0.010 N / mm for version B1, and 0.012 N / mm for version C. The difference between the bending force at P3 and the bending force at P2, divided by the distance between P3 and P2, provided a second flexibility slope. The second flexibility slope was approximately 0.008 N / mm for version A, 0.006 N / mm for version B1, and 0.007 N / mm for version C. The average of the first and second flexibility slopes yielded the average flexibility slope of the tip section.In some tests, a fourth distal tip point was measured, such that the average tip section flexibility inclination included this additional segment when calculating the average inclination (e.g., the segment between P3 and P4). The average tip section flexibility inclination for each version of the tested catheter systems was at least 0.005 N / mm. For example, the average tip section flexibility inclination was approximately 0.008 N / mm for version A and version B1, and approximately 0.010 N / mm for version C. The difference between the bending force of S1 and the bending force of S2 (either P3 or P4), divided by the distance between S1 and S2 (either P3 or P4), provided an initial system flexibility inclination. The first system flexibility tendency when P3 is used as S2 was approximately 0.024 N / mm for version A, 0.013 N / mm for version B1 and approximately 0.009 N / mm for version C.In this calculation, the ratio between the initial system flexibility slope and the average flexibility slope of the flexible section was approximately 3.0 for version A, approximately 1.6 for version B, and approximately 0.9 for version C. The initial system flexibility slope, used with P4 as S2, was approximately 0.035 N / mm for version B1 and approximately 0.02 N / mm for version C. In this calculation, the ratio between the initial system flexibility slope and the average flexibility slope of the flexible section was approximately 4.4 for version B1 and approximately 2.0 for version C. Regardless of which point was used for S2 (P3 or P4), the ratio between the initial system flexibility slope and the average flexibility slope of the tip section was less than approximately 5 for each version.

[0204] Fig. Figures 14A to 14D illustrate the bending forces of the various points described above in relation to the distance in mm along a length of the system. Fig. shows data for the version A system, which has a catheter feeder element 300 having an outer diameter dimensioned to extend through a catheter with an inner diameter of approximately 0.054 inches. Fig. Figure 14B illustrates data for the version B1 system, which has a catheter feeder element 300 with an outer diameter dimensioned to extend through a catheter with an inner diameter of approximately 0.070 inches. Fig. Figure 14C illustrates data for another version (version B2) of a catheter system which has a catheter feeder element 300 with an outer diameter dimensioned to extend through a catheter with an inner diameter of about 0.070 inch. Fig. Figure 14D illustrates data for the version C system, which includes a catheter feeder element 300 having an outer diameter dimensioned to extend through a catheter with an inner diameter of approximately 0.088 inches.

[0205] The Fig. Figures 14A-14D illustrate how the slopes of the lines are essentially constant or nearly constant and exhibit essentially no stepwise increases in the bending force slope from one segment to the next along the length of the catheter system. In particular, none of the tested versions exhibited any abrupt increases in bending force between the distal peak points (i.e., the points of the catheter advance element extending distally to the distal end of the catheter) and the system point (i.e., the combination of catheter and catheter advance element). Thus, the overall slope of the system in the advance configuration is essentially constant over a length of the system, for example, over a length from the most distal end (0 mm) to approximately 35 mm proximal to the most distal end of the system.

[0206] In every version tested, the bending force of the distal end of the catheter delivery element at P1 was significantly lower than the bending force of the distal end of the catheter through which it extends (e.g., at least approximately twice as high) (see also Table 4 below). The bending force of the distal end of the catheter delivery element at P1 was no more than approximately 0.05 N. The bending force of the catheter delivery element increased along the length of the distal tip section and approached the higher bending force of the distal end of the catheter. For example, the stiffness of the distal tip section increased at least twice as much along its length and approached the bending force of the distal end of the catheter. The bending force of the catheter system along its length exhibited a generally constant slope. This generally constant slope of the increased bending force for the distal section of the catheter delivery element (in Fig. 13B (shown as a dashed line) transitioned to a generally constant slope of the increased bending force for the combined system (in Fig. 13B (shown as a dashed line), such that there is no significant jump in the slope between the two. The bending force of the distal segment had a slope that transitioned into the slope of the overall system (i.e., additive bending force between catheter and catheter delivery element, shown by the dashed line) without a significant jump in the slope from one segment to the next.

[0207] Corresponding points on another catheter system (GUIDELINER navigation catheter system; Vascular Solutions, Minneapolis, MN) were tested for comparison. The data are provided in Table 2 below and also in Fig. Figure 14E illustrates the bending force of the various points in relation to the distance in mm along a length of the GUIDELINER system. Table 2 Kathetersystem P1 P2 P3 S2 S1 Distale Spitzenpunkt(Nur Navigationskatheter) Systempunkte 8F GUIDELINERNavigationskatheter 0,114 N 0,137N 0,141 N 0,141 N 0,636 N Distanz entlang der Längedes Systems vom distalstenEndpunkt 5 mm 10 mm 15 mm 15 mm 20 mm

[0208] The first bending force of P1 was greater than 0.05 N, specifically approximately 0.114 N. Various calculations were performed using the bending force data shown in Table 2. The first flexibility slope for the GUIDELINER system was approximately 0.005 N / mm. The second flexibility slope for the GUIDELINER system was approximately 0.001 N / mm. The average flexibility slope of the tip section for the GUIDELINER system was approximately 0.003 N / mm. The first system flexibility slope for the GUIDELINER system was approximately 0.10 N / mm. The ratio between the first system flexibility slope and the average flexibility slope of the tip section for the GUIDELINER system was greater than 30. This ratio numerically illustrates what is in Fig. 14E is graphically represented. Fig. Figure 14E shows that the GUIDELINER catheter system exhibits a large jump in gradient from the flexibility of the flexible segment of the navigation catheter, which extends distally to the distal end of the catheter through which it passes, to the flexibility of the system as a whole. These increased jumps in gradient mean that there are sharp changes in stiffness along the length of the catheter system, preventing the GUIDELINER catheter system from advancing around the curves of the tortuous vessels that traverse the bony anatomy of the skull. The catheter tip cannot navigate such curves. In contrast, the catheter systems described herein have lower gradient values, illustrating that they have the most uniform change in stiffness possible from the distal to the proximal end and are therefore suitable for delivery through tortuous anatomical structures.

[0209] Table 3 below shows the slopes of the catheter systems described herein compared to the slopes of the GUIDELINER navigation catheter system. The "average tip section flexibility slope" was calculated. More precisely, the average tip section flexibility slope is the average of the slopes of segments P1 to P2, P2 to P3, and P3 to P4, if available. Additional tip section segments may be included. The "S2-S1 segment inclination" is the inclination of the segment between system points S2 and S1. System point S2 may be the same point or a different point than one of the other points (e.g., P4 or P3). The "P1-S1 segment inclination" is the inclination of a line drawn directly from the most distal point P1 to system point S1. Table 3 Kathetersystem P1 (N) P2 (N) P3 (N) P4 (N) S2 (N) S1 (N) DurchschnittlicheFlexibilitätsneigung desSpitzenabschnitts (N / mm) Steigung desSegmentsS2-S1(N / mm) Slope of segment P1-S1 (N / mm) Version A0.054 inch 0,023 0,079 0,087 n / a 0,087 0,208 0,0080 0,0202 0,0132 Ratio to the average flexibility tendency of the peak segment 1 2,52 1,65 Version B10.070 inch 0,025 0,180 0,211 0,233 0,233 0,442 0,0093 0,0349 0,0149 Ratio to the average flexibility tendency of the peak segment 1 3,76 1,61 Version B20,070 inch 0,025 0,180 0,211 0,233 0,233 0,345 0,0093 0,0187 0,0114 Ratio to the average flexibility tendency of the peak segment 1 2,01 1,23 Version C0.088 inch 0,029 0,210 0,245 0,299 0,299 0,415 0,0124 0,0193 0,0133 Ratio to the average flexibility tendency of the peak segment 1 1,56 GUIDELINER Navigation Catheter 0,114 0,137 0,141 n / a 0,141 0,636 0,0026 0,0990 0,0348 Ratio to the average flexibility tendency of the peak segment 1 37,40 13,13

[0210] The conical distal tip section experienced a change in bending force along its length, which increased at least twofold. The conical distal tip section of the catheter delivery element in versions A, B1, B2, and C exhibited a minimum inclination of at least 0.005 N / mm. In contrast, the increase in bending force along the length of the GUIDELINER was only about 1.2 times greater. Furthermore, the GUIDELINER exhibited an average tip section flexibility inclination of less than approximately 0.003 N / mm. The inclination of each of the catheter systems (versions A, B1, B2, and C) increased by no more than about fivefold from distal point P1 to system point S1, whereas in the GUIDELINER it increased more than 30-fold from 0.114 N / mm.

[0211] Table 4 below shows the bending forces of the distal tip of the catheter delivery element relative to the bending forces of the distal end of the catheter. The point measured in Table 4 below, designated as "catheter point C1," was a point along a length of the catheter closest to the distal end that could utilize the systems described herein, for example, a catheter measurement length from the distal end of at least approximately 5 mm. The bending force (or flexibility) of the distal tip at P1 was approximately 16% of the bending force (or flexibility) of C1 for version A, approximately 10% for version B1, and approximately 8% for version C. Thus, the bending force at P1 ranged from approximately 5% to 15% of the bending force at C1. The bending force (or flexibility) of the flexion point near the proximal end of the distal tip (e.g. P3 or P4) was approximately 59% for version A, approximately 91% for version B1 and approximately 82% for version C.Thus, the bending force at the flexion point was between approximately 50% and 90% of the bending force (or flexibility) of C1. In contrast, the distal tip P1 on the GUIDELINER was stiffer than the same tip in versions A, B1, or C. The proximal point P3 on the GUIDELINER exhibited a greater bending force than the distal tip P1, but this bending force was much less than the bending force of the catheter point C1 (i.e., only 23% of the stiffness of the catheter point C1). Therefore, there was a greater difference between the bending force of the navigation catheter at P3 compared to the bending force of the catheter at C1 compared to the versions of the catheter systems described herein. This difference contributes to the greater stepwise increase in the gradients of the GUIDELINER catheter system, as best illustrated in [reference missing]. Fig. 14E can be seen. Table 4 Catheter system Distal tip P1(N) Proximal point P3 / P4(N) Catheter point C1(N) (Catheter delivery element only) Catheter only Version A 0.054" 0,023 0,087 0,147 16 % 59 % 100 % Version Bl 0.070 inch 0,025 0,233 0,256 10 % 91 % 100 % Version C 0.088 inch 0,029 0,299 0,366 8% 82 % 100 % 8F GUIDELINERNavigation catheter 0,114 0,141 0,624 18 % 23 % 100 %

[0212] Table 5 below shows the bending force of P1 of the catheter delivery element relative to the bending force of a section of the proximal extension of the catheter delivery element. The point EI selected for testing on the proximal extension was located approximately 20 cm proximal to the tubular section of the catheter delivery element. Point EI exhibited a bending force of approximately 9.21 N. The bending force of the catheter delivery element at the distal tip P1 was no more than approximately 0.30% of the bending force of the proximal extension at EI. The ratio of the bending force at point EI to the bending force at the distal tip P1 was at least approximately 300. The proximal extension of the catheter delivery element in version C was approximately 318 times stiffer than the distal tip of the catheter delivery element at P1, version B1 was approximately 368 times stiffer, and version A was approximately 400 times stiffer. Table 5 Catheter system P1 (N) E1 (N) % stiffness Relationship Version A 0.054" 0,023 9,21 0,25 % 400 Version Bl0,070" 0,025 9,21 0,27 % 368 Version C0,088" 0,029 9,21 0,30 % 318 GUIDELINER Navigation Catheter 0,114 17,52 0,65 % 154 Orion-21 0,137 8,36 1,64 % 61

[0213] Two additional catheter systems were analyzed for comparison. The bending force of the GUIDELINER navigation catheter at point El was approximately 17.52 N, greater than that of all other tested versions. The bending force of the distal tip at point P1 was also higher than that of the catheter system versions described herein. The bending force of the navigation catheter at the distal tip P1 was approximately 0.65% of the bending force of the proximal extension at El. Furthermore, the bending force at point El of the GUIDELINER navigation catheter was only 154 times greater than at the distal tip P1. The ORION-21 catheter (Medtronic, Minneapolis, MN) exhibited a bending force at the distal tip P1 that was approximately 1.64% of the bending force at El. The bending force at point El of the ORION-21 was only about 60 times greater than its distal tip at P1.

[0214] The data described herein provide a numerical picture of the smooth transition in flexibility along the length of the various catheter systems described herein, offering optimal maneuverability without kinking. The catheter systems described herein feature distal ends that are exceptionally flexible, transitioning to proximal ends that are exceptionally stiff to ensure optimal torque and handling. The transitions in flexibility along the length of the system are designed so that the two components work together seamlessly, as if they were a single component, without large jumps in stiffness from one segment to the next.

[0215] The implementations describe catheters and delivery systems, as well as procedures for delivering catheters to target anatomical structures. While some implementations are specifically described for delivering catheters to a target vessel within a neurovascular anatomy, such as a cerebral vessel, the implementations are not limited to this, and certain implementations may be suitable for other uses. For example, the catheters can be adapted for delivery to various neuroanatomical structures, such as subclavian, vertebral, and carotid vessels, as well as coronary or peripheral vessels, to name just a few possible applications. Although the systems described herein are presented as useful for treating a particular disease or pathology, the diseases or pathologies to be treated can vary and are not intended to be limiting.The use of the terms "embolus," "embolic," "embolisms," "thrombus," "occlusion," "clot," etc., in connection with a treatment target using the devices described herein, is not intended to be restrictive. These terms may be used interchangeably and may include, but are not limited to, blood clots, air bubbles, small fatty deposits, or other objects that are carried in the bloodstream to a distant location or that form at a point in a vessel. These terms may be used interchangeably herein to describe anything that may cause partial or complete occlusion of blood flow through or within the vessel.

[0216] In various implementations, the description refers to the illustrations. However, certain implementations can be practiced without one or more of these specific details or in combination with other known methods and configurations. The description presents numerous specific details, such as particular configurations, dimensions, and procedures, to provide a comprehensive understanding of the implementations. In other cases, known methods and manufacturing techniques have not been described in great detail to avoid unnecessarily complicating the description. References in this description to "an embodiment," "an implementation," or similar terms mean that a particular described feature, structure, configuration, or property is included in at least one embodiment or implementation.Therefore, the terms "one embodiment," "one implementation," or similar expressions that appear at various points in this description do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, configurations, or properties in one or more implementations may be combined in any suitable manner.

[0217] The use of relative terms throughout the description can denote a relative position or direction. For example, "distal" can denote a first direction away from a reference point. Similarly, "proximal" can denote a location in a second direction opposite to the first. The reference point used here can be the operator, so the terms "proximal" and "distal" refer to an operator using the device. A region of the device that is closer to an operator can be referred to herein as "proximal," and a region of the device that is farther away from an operator can be referred to herein as "distal."Similarly, the terms “proximal” and “distal” may also be used herein to denote anatomical locations of a patient from the operator’s perspective, or from the perspective of an entry point, or along a path of delivery from the system’s entry point. Therefore, a proximal location may denote a site in the patient closer to an entry point of the device along a path of delivery to a target, and a distal location may denote a site in the patient farther from an entry point of the device along a path of delivery to the target. However, these terms are provided only for the purpose of establishing relative reference systems and are not intended to restrict the use or orientation of the catheters and / or delivery systems to any particular configuration described in the various implementations.

[0218] Although this specification contains many details, these should not be interpreted as limitations on the scope of what is claimed or may be claimed, but rather as descriptions of features specific to certain embodiments. Certain features described in this specification in connection with separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in connection with a single embodiment may also be implemented separately in several embodiments or in any suitable subcombination. Furthermore, features described above may be, and even originally claimed as, acting in certain combinations.In some cases, one or more features from a claimed combination can be removed, and the claimed combination can be focused on a subcombination or a variation of a subcombination. Likewise, the operations shown in the drawings in a particular order should not be interpreted as requiring that these operations be performed in the order shown or in sequential order, or that all of the operations shown must be performed to achieve the desired results. Only some examples and implementations are disclosed. Variations, modifications, and improvements to the described examples and implementations, as well as other implementations, may be made based on what has been disclosed.

[0219] In the foregoing descriptions and in the claims, expressions such as "at least one of" or "one or more of" may appear, followed by a conjunctive list of elements or features. The term "and / or" may also appear in a list of two or more elements or features. Unless explicitly or implicitly contradicted by the context in which it is used, such an expression shall mean each of the listed elements or features individually or each of the listed elements or features in combination with any of the other listed elements or features. For example, the expressions "at least one of A and B," "one or more of A and B," and "A and / or B" shall each mean "A alone, B alone, or A and B together." A similar interpretation applies to lists including three or more elements.For example, the expressions “at least one of A, B and C”, “one or more of A, B and C” and “A, B and / or C” are each to be understood as meaning “A alone, B alone, C alone, A and B together, A and C together, B and C together or A and B and C together”.

[0220] The use of the term “based on” above and in the claims is intended to mean “at least partially based on” that an unmentioned feature or element is also permissible.

[0221] The invention is further described in the following numbered paragraphs: 1. Coaxial catheter system, the system comprising the following: a catheter, including: a distal catheter section with a lumen and a distal end with an opening from the lumen, wherein the lumen has an inner diameter at the distal end of at least approximately 0.052"; and a proximal extension that is connected to and extends proximal to the distal catheter segment, wherein the proximal extension is less flexible than the distal catheter segment; and a catheter delivery element, comprising: a tubular section with an inner diameter of at least about 0.014" to about 0.024", an outer diameter, wherein the outer diameter has at least one abutment point; wherein the difference between the inner diameter of the distal catheter section and the outer diameter of the tubular section at this abutment point is not more than about 0.010"; a proximal extension that is connected to and extends proximal to the tubular section, wherein the proximal extension is less flexible than the tubular section; and a tip section which is arranged distal to the at least one end point of the tubular section, wherein the tip section has a length and tapers along at least a section of the length of the tip section, wherein the coaxial catheter system has a delivery configuration characterized by: a) the catheter delivery element, which is positioned coaxially within the lumen of the distal catheter section, wherein the at least one contact point of the tubular section is substantially aligned with the distal end of the distal catheter section, and b) wherein the tip section in the feed configuration has at least three points spaced apart along the length of the tip section, comprising at least three points: a distal point of the at least three points, which is located at a distance proximal to the most distal end of the catheter delivery element, wherein the distal point has a first bending force which is not greater than about 0.05 Newtons; an intermediate point of at least three points, which is arranged at a distance proximal to the distal point, wherein the intermediate point has a second bending force; and a proximal point of the at least three points, which is arranged at a distance proximal to the intermediate point, wherein the proximal point has a third bending force; and c) wherein the coaxial system has at least two system points along a length of the coaxial system, the at least two system points comprising: a first system point of the at least two system points, which is arranged proximal to the distal end of the catheter section, wherein the first system point has a first system bending force; and a second system point of at least two system points, which is arranged distal to the first system point at a distance that is at least approximately 1 mm distal to the distal end of the catheter section, wherein the second system point may be the same or a different one than the proximal point, wherein the second system point has a second system bending force. 2. Coaxial catheter system according to paragraph 1, where the difference between the second bending force and the first bending force divided by the distance between the distal point and the intermediate point corresponds to a first flexibility tendency; where a difference between the third bending force and the second bending force divided by a distance between the intermediate point and the proximal point corresponds to a second flexibility tendency; where an average of the first flexibility tendency and the second flexibility tendency defines an average flexibility tendency of the peak section; where a difference between the bending force of the first system and the bending force of the second system, divided by the distance between the first system point and the second system point, corresponds to a third flexibility tendency; and where the ratio between the third flexibility tendency and the average flexibility tendency of the peak section is less than approximately 25. 3. Coaxial catheter system according to paragraph 1, wherein the proximal extension of the catheter delivery element has at least one stiffness point located within approximately 125 cm from the distal end of the catheter delivery element, wherein the at least one stiffness point has a bending force, wherein the ratio of the bending force of the at least one stiffness point to the first bending force of the distal point is at least approximately 100. 4. Coaxial catheter system according to paragraph 1, wherein the proximal extension of the catheter delivery element has at least one stiffness point located within approximately 125 cm from the most dis...

Claims

[1] Coaxial catheter system (150) comprising: a catheter (200), comprising: a distal catheter section (222) with a lumen (223) and a distal end with an opening from the lumen, wherein the lumen (223) has an inner diameter at the distal end of at least about 1.3 mm (0.052 in); and a proximal extension connected to and extending proximal to the distal catheter segment (222), wherein the proximal extension is less flexible than the distal catheter segment; and a catheter delivery element (300), comprising: a tubular section with an inner diameter of at least about 0.35 mm (0.014 in) up to about 0.6 mm (0.024 in), an outer diameter, wherein the outer diameter has at least one abutment point; wherein the difference between the inner diameter of the distal catheter section (222) and the outer diameter of the tubular section at this abutment point is not more than about 0.25 mm (0.010 in); a proximal extension that is connected to and extends proximal to the tubular section, wherein the proximal extension is less flexible than the tubular section; and a tip section which is arranged distal to the at least one end point of the tubular section, wherein the tip section has a length and tapers along at least a section of the length of the tip section, wherein the coaxial catheter system (150) has a delivery configuration characterized by: a) the catheter delivery element (300) which is positioned coaxially within the lumen (223) of the distal catheter section (222), wherein the at least one contact point of the tubular section is substantially aligned with the distal end of the distal catheter section (222), and b) wherein the tip section in the feed configuration has at least three points spaced apart along the length of the tip section, comprising at least three points: a distal point (P1) of at least three points, which is located at a distance proximal to the distal end of the catheter delivery element (300), wherein the distal point (P1) has a first bending force which is not greater than about 0.05 Newton; an intermediate point (P2) of at least three points, which is arranged at a distance proximal to the distal point (P1), wherein the intermediate point (P2) has a second bending force; and a proximal point (P3) of the at least three points, which is arranged at a distance proximal to the intermediate point (P2), wherein the proximal point (P3) has a third bending force; and c) wherein the coaxial system has at least two system points along a length of the coaxial system, the at least two system points comprising: a first system point (S1) of the at least two system points, which is arranged proximal to the distal end of the catheter section (222), wherein the first system point (S1) has a first system bending stiffness; and a second system point (S2) of the at least two system points, which is arranged distal to the first system point (S1) at a distance that is at least approximately 1 mm distal to the distal end of the catheter section (222), wherein the second system point (S2) may be the same as or different from the proximal point (P3), wherein the second system point (S2) has a second system bending stiffness, wherein the bending force of the coaxial catheter system (150) has a generally constant slope over its length, wherein the generally constant slope of the increasing bending force for the distal tip section of the catheter delivery element (300) transitions into a generally constant slope of the increasing bending force for the coaxial catheter system (150), such that there is no significant increase or change in slope between the two. [2] Coaxial catheter system (150) according to claim 1, where the difference between the second bending force and the first bending force divided by the distance between the distal point and the intermediate point (P2) corresponds to a first flexibility tendency; where a difference between the third bending force and the second bending force divided by a distance between the intermediate point (P2) and the proximal point (P3) corresponds to a second flexibility tendency; where an average of the first flexibility tendency and the second flexibility tendency defines an average flexibility tendency of the peak section; where a difference between the bending force of the first system and the bending force of the second system, divided by the distance between the first system point (S1) and the second system point (S2), corresponds to a third flexibility tendency; and where the ratio between the third flexibility tendency and the average flexibility tendency of the peak section is less than approximately 25. [3] Coaxial catheter system (150) according to claim 1, wherein the proximal extension of the catheter delivery element (300) has at least one stiffness point located within about 125 cm from the distal end of the catheter delivery element (300), wherein the at least one stiffness point has a bending force, wherein the ratio of the bending force of the at least one stiffness point to the first bending force of the distal point is at least about 100. [4] Coaxial catheter system (150) according to claim 1, wherein the proximal extension of the catheter delivery element (300) has at least one stiffness point located within about 125 cm from the distal end of the catheter delivery element (300), wherein the at least one stiffness point has a bending force, wherein the ratio of the bending force of the at least one stiffness point to the first bending force of the distal point (P1) is at least about 200. [5] Coaxial catheter system (150) according to claim 1, wherein the proximal extension of the catheter delivery element (300) has at least one stiffness point located within about 125 cm from the distal end of the catheter delivery element (300), wherein the at least one stiffness point has a bending force, wherein the ratio of the bending force of the at least one stiffness point to the first bending force of the distal point (P1) is greater than about 300. [6] Coaxial catheter system (150) according to claim 1, wherein the length of the tip section is at least 1 cm up to 4 cm. [7] Coaxial catheter system (150) according to claim 6, wherein the ratio of the third bending force of the proximal point (P3) to the first bending force of the distal point (P1) is at least 2. [8] Coaxial catheter system (150) according to claim 1, wherein the ratio of the first system bending stiffness to the first bending force of the distal point (P1) is at least 2. [9] Coaxial catheter system (150) according to claim 1, wherein the distal catheter section (222) has a catheter point located at a distance of at least 5 mm proximal to the distal end, wherein the catheter point has a catheter bending stiffness. [10] Coaxial catheter system (150) according to claim 9, wherein the first bending force of the distal point (P1) is about 5% to 15% of the catheter bending stiffness. [11] Coaxial catheter system (150) according to claim 9, wherein the third bending force of the proximal point (P3) is about 50% to 90% of the catheter bending stiffness. [12] Coaxial catheter system (150) according to claim 1, wherein the difference between the first bending force at the distal point (P1) and the third bending force at the proximal point (P3) is a function of wall thickness. [13] Coaxial catheter system (150) according to claim 1, wherein the tubular section of the catheter delivery element (300) has a radiopaque marker band embedded in or positioned above a wall of the tubular section, wherein the radiopaque marker band is positioned at the snag point. [14] Coaxial catheter system (150) according to claim 13, wherein the radiopaque marker band has a proximal edge, a distal edge and a width between the proximal edge and the distal edge, wherein in the delivery configuration the proximal edge of the radiopaque marker band is substantially aligned with the distal end of the distal catheter section (222) such that the radiopaque marker band remains outside the lumen (223) of the distal catheter section (222). [15] Coaxial catheter system (150) according to claim 1, wherein the outer diameter of the tubular section has a length of at least 5 cm to 10 cm, wherein the snag point is arranged along at least one section of the length. [16] Coaxial catheter system (150) according to claim 15, wherein the outer diameter is substantially uniform along the length. [17] Coaxial catheter system (150) according to claim 15, wherein the outer diameter is not substantially uniform along the length. [18] Coaxial catheter system (150) according to claim 1, wherein the distal point (P1) is arranged at a distance of at least 5 mm proximal to the distal end of the catheter delivery element (300). [19] Coaxial catheter system (150) according to claim 1, wherein the first system point (S1) is located at least about 5 mm proximal to the distal end of the catheter section (222). [20] Coaxial catheter system (150) according to claim 1, wherein the distal point (P1) is located 5 mm proximal to the distal end of the catheter delivery element (300), the intermediate point (P2) is located 12 mm proximal to the distal end of the catheter delivery element, and the proximal point (P3) is located 13 mm proximal to the distal end of the catheter delivery element. [21] Coaxial catheter system (150) according to claim 20, wherein the first system point (S1) is located 19 mm proximal to the distal end of the catheter delivery element and the second system point (S2) is located 13 mm proximal to the distal end of the catheter delivery element. [22] Coaxial catheter system (150) according to claim 1, wherein the distal point (P1) is located 5 mm proximal to the distal end of the catheter delivery element (300), the intermediate point (P2) is located 20 mm proximal to the distal end of the catheter delivery element, and the proximal point (P3) is located 25 mm proximal to the distal end of the catheter delivery element. [23] Coaxial catheter system (150) according to claim 22, wherein the first system point (S1) is located 33 mm proximal to the distal end of the catheter delivery element and the second system point (S2) is located 25 or 27 mm proximal to the distal end of the catheter delivery element. [24] Coaxial catheter system (150) according to claim 22, wherein the first system point (S1) is located 34 mm proximal to the distal end of the catheter delivery element and the second system point (S2) is located 25 or 28 mm proximal to the distal end of the catheter delivery element, wherein the second system point (S2) is identical to the proximal point (P3). [25] Catheter system according to claim 1, wherein the ratio between the third flexibility inclination and the average flexibility inclination of the tip section is less than 15. [26] Catheter system according to claim 1, wherein the ratio between the third flexibility inclination and the average flexibility inclination of the tip section is less than 5. [27] Catheter system according to claim 1, wherein the distal point (P1) is arranged 3 mm to 5 mm proximal to the distal end of the catheter delivery element (300).

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