Catheter for Retrieving Plug

Abstract

Disclosed is a system for removing embolic material from an intravascular site. An elongated, flexible tubular body has a tubular sidewall defining at least one axially extending lumen. An axial restraint is carried by the inner surface of the sidewall and exposed to the lumen. A rotatable core wire is extendable through the lumen and may include an obstruction-engaging tip. The core wire carries a limiting device having a distally facing bearing surface that rotatably engages the restraining device. The limiting device and restraining device are configured to permit rotation of the core wire but limit distal advancement of the tip to a predetermined relationship with the distal end of the tubular body.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application is a continuation - in - part of U.S. Patent Application No. 16 / 589,563, filed on October 1, 2019, and also claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63 / 026,898, filed on May 19, 2020, the entire contents of each of which are incorporated herein by reference. In addition, International Patent Application No. PCT / US2019 / 029709, filed on April 29, 2019, is incorporated herein by reference.

Background Art

[0002] Stroke is the third leading cause of death in the United States and the most disabling neurological disorder. Nearly 700,000 patients suffer from stroke annually. Stroke is a syndrome characterized by the acute onset of neurological deficits that last for at least 24 hours, reflecting a focal involvement of the central nervous system and resulting from a disruption of cerebral circulation. Its incidence increases with age. Risk factors for stroke include systolic or diastolic hypertension of the heart, hypercholesterolemia, smoking, heavy alcohol consumption, and the use of oral contraceptives, among others.

[0003] Hemorrhagic stroke accounts for 20% of the annual stroke population. Hemorrhagic stroke often occurs when an aneurysm or arteriovenous malformation ruptures and bleeds into the brain tissue, resulting in a cerebral infarction. The remaining 80% of the stroke population is ischemic stroke, which is caused by blocked blood vessels that deprive the brain of oxygen - carrying blood. Ischemic stroke is often caused by emboli or fragments of thrombotic tissue breaking off from other sites or the cerebral blood vessels themselves and further occluding narrow distal cerebral arteries. When a patient presents with neurological symptoms and signs that completely resolve within one hour, the term transient ischemic attack (TIA) is used. Etiologically, TIA and stroke share the same pathophysiological mechanisms and thus represent a continuum based on the duration of symptoms and the extent of ischemic injury.

[0004] Emboli may form around the heart valves or within the left atrial appendage while the heart rate is irregular and then detach and flow into the distal regions of the body following the bloodstream. These emboli can migrate to the brain and cause embolic stroke. As discussed below, many of such occlusions occur in the middle cerebral artery (MCA), but it is not the only site where emboli lodge.

[0005] When a patient presents with neurological deficits, a diagnostic hypothesis regarding the cause of the stroke can be formulated based on the patient's medical history, examination of stroke risk factors, and neurological examination. If an ischemic event is suspected, the clinician can tentatively assess whether the patient has a cardioembolic cause, extracranial or intracranial aortic disease, small-vessel parenchymal disease, or a hematological or other systemic disease. A head CT scan is often performed to determine whether the patient has suffered an ischemic or hemorrhagic injury. In subarachnoid hemorrhage, parenchymal hematoma, or intraventricular hemorrhage, blood may be present on the CT scan.

[0006]

[0007] ​However, treatment with systemic t-PA is associated with an increased risk of intracerebral hemorrhage and other hemorrhagic complications. Patients treated with t-PA were more likely to have symptomatic intracerebral hemorrhage persist for up to 36 hours from the start of treatment. Administering t-PA more than 3 hours after the onset of stroke increases the frequency of symptomatic intracerebral hemorrhage. In addition to the time constraints in the use of t-PA in acute ischemic stroke, other contraindications include the following: whether the patient has had a prior stroke or severe head trauma in the past 3 months, whether the patient has a systolic blood pressure of 185 mmHg or higher, or a diastolic blood pressure of 110 mmHg or higher, whether the patient requires aggressive treatment to lower blood pressure to the defined limits, whether the patient is taking anticoagulants or has a bleeding tendency, and / or whether the patient has recently undergone an invasive surgical procedure, etc. Therefore, only a small percentage of selected stroke patients are eligible to receive t-PA.

[0008] Also, occlusive emboli have been mechanically removed from various sites in the vascular system for many years. Mechanical therapies include clot capture and removal, clot lysis, clot disruption and aspiration, and / or formation of communication pathways for flow through the thrombus. One of the first mechanical devices developed for stroke treatment is the MERCI Retriever System (Concentric Medical, Redwood City, California). To access the internal carotid artery (ICA) from the femoral artery, a guide catheter with a balloon tip is used. A microcatheter is placed through the guide catheter and used to deliver a retriever with a coiled tip beyond the clot, and then the microcatheter is withdrawn to leave the retriever around the clot. The balloon is then inflated, and a syringe is connected to the balloon guide catheter to aspirate the guide catheter while withdrawing the microcatheter and retriever into the balloon guide catheter to finally remove the clot. This device initially had good results compared to thrombolytic therapy alone.

[0009] Other thrombectomy devices use an expandable framework, basket, or snare to capture and retrieve blood clots. Temporary stents, sometimes called stent retrievers or reperfusion devices, are used not only to remove or retrieve blood clots but also to restore blood flow in blood vessels. A series of devices that use active laser or ultrasonic energy to fragment blood clots are also used. Other active energy devices are used in combination with the injection of intra-arterial thrombolytics to promote the dissolution of blood clots. Many of these devices are used in combination with aspiration to assist in removing blood clots and reducing the risk of embolism. Aspiration of blood clots is also used with single-lumen catheters and syringes or suction pumps, with or without disruption of the blood clot. Devices that apply a driven fluid vortex in combination with aspiration have been used to improve the effectiveness of this thrombectomy. Finally, when removal or dissolution of the blood clot is not possible, patent lumens through the blood clot are created using balloons or stents.

[0010] Notwithstanding the foregoing, there remains a need for novel devices and methods for treating vascular embolisms in the body, including acute ischemic stroke and embolic cerebrovascular disease. SUMMARY OF THE INVENTION

[0011] In accordance with one aspect of the present invention, a system for removing an embolic substance from an intravascular site is provided. The system includes a tubular body that is an elongated flexible tube having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. An axial restraint device is carried by the sidewall and is exposed within the lumen. A rotatable core wire is telescopically extendable through the lumen and has a proximal end and a distal end. A limiting device is carried by the core wire, the limiting device having a bearing surface that rotatably engages the restraint device, and a thrombus gripping tip is provided at the distal end of the core wire. The limiting device and the restraint device are configured to allow rotation of the core wire but limit distal advancement of the tip to about 6 mm or less beyond the distal end of the tubular body.

[0012] The limiting device and the restraint device may be configured to allow rotation of the core wire but limit distal advancement of the tip to about 3 mm or less beyond the distal end of the tubular body. The thrombus gripping tip may include a helical thread shape. The limiting device and the restraint device may be configured to allow rotation of the core wire but limit distal advancement of the tip to exposure between about 1 and 3 full rotations of the thread shape beyond the distal end of the tubular body.

[0013] The axial restraint device may include a proximally facing bearing surface. The axial restraint device may include a radially inwardly extending protrusion. The axial restraint device may include an annular flange. The limiting device may include a distally facing bearing surface. The limiting device may include a radially outwardly extending protrusion. The radially outwardly extending protrusion may be configured to slidably contact the restraint device.

[0014] The proximal bearing surface of the axial restraint device may be within a range of about 30 cm from the distal end of the tubular body. The proximal bearing surface of the axial restraint device may be within a range of about 4 cm to about 12 cm from the distal end of the tubular body. The limiting device may be positioned within the most distal about 25% of the core wire length.

[0015] The helical thread shape may have a maximum outer diameter that is about 90% or less of the inner diameter of the lumen, leaving an annular flow path between the tip and the inner surface of the side wall. The helical thread shape may have a blunted outer edge.

[0016] The core wire may be removably positionable within the tubular body. The system may further include a handle configured to manually rotate the core wire.

[0017] The helical thread shape may extend through a rotation of about 8 full rotations or less. The helical thread shape may have an outer diameter that increases from a first diameter near the distal tip to a second maximum outer diameter in the proximal direction and then decreases from the maximum outer diameter to a third diameter in the proximal direction. The inner diameter of the tubular body adjacent to the blood clot grasping tip may be at least about 0.015 inches larger than the maximum outer diameter of the tip.

[0018] In accordance with one aspect of the present invention, a torque transmission system is provided for rotationally orienting the distal end of a catheter. The system includes a tubular body that is an elongated flexible tubular body having a proximal end, a distal end, and a tubular side wall defining at least one lumen extending axially therethrough. A first engagement surface is carried by the side wall and exposed within the lumen. A torque wire is telescopically extendable through the lumen, the torque wire having a proximal end and a distal end. A second engagement surface is carried by the torque wire. Forward movement of the distal end of the torque wire places the second engagement surface in a state of rotational coupling engagement with the first engagement surface, which is configured to cause rotation of the distal end of the catheter upon rotation of the torque wire in at least a first direction.

[0019] The first engagement surface may include at least one inclined surface and may be carried by a protrusion extending radially inwardly. The protrusion may include a ring positioned within the lumen. The second engagement surface may include a surface facing distally, which surface may be inclined with respect to the longitudinal axis of the catheter.

[0020] In accordance with another aspect of the present invention, a system for removing an embolic substance from an intravascular site is provided. The system includes a tubular body that is an elongated flexible tube having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. A first engagement surface is carried by the sidewall and exposed within the lumen. A tap wire is telescopically extendable through the lumen and has a proximal end and a distal end. A second engagement surface is carried by the tap wire. Forward movement of the tap wire distally causes the second engagement surface to contact the first engagement surface and transfers momentum from the tap wire to the distal end of the tubular body.

[0021] The first engagement surface may include a proximally facing surface and may be carried by a radially inwardly extending protrusion. The first engagement surface may include an annular flange. The second engagement surface may include a distally facing surface that may be carried by the distal end of the tap wire. The distally facing surface may be on a hammerhead carried by the wire.

[0022] In accordance with a further aspect of the present invention, a torque transmission system for rotationally orienting the distal end of a catheter is provided. The system includes a tubular body that is an elongated flexible tube having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. A first connector is provided on the sidewall and exposed within the lumen. A torque wire is telescopically extendable through the lumen and has a proximal end and a distal end. A second, complementary connector is carried by the torque wire. Coupling the first and second connectors enables rotation of the distal end of the catheter in response to rotation of the torque wire.

[0023] The first connector may include at least one toothed portion having an oblique angle, i.e., a protruding portion extending radially inward. The protruding portion may include a ring positioned within the lumen. The ring may include at least two toothed portions having an oblique angle and extending in the proximal direction. The second connector may include a distally facing surface carried by a torque wire. The distally facing surface may include at least one inclined surface. The second connector may be movable radially outward and may include an inflatable balloon. Further, the first connector may include an inner surface on the sidewall. The first connector may include the sidewall of an axially extending elongated groove configured to receive a protrusion on the torque wire.

[0024] Also provided is a method of rotationally orienting a catheter. The method includes advancing the catheter to a site within a body cavity, the catheter having a central lumen and a distal end. A torque wire is advanced within the lumen. A first connector on the torque wire engages a second connector on the catheter to rotate the torque wire, thereby rotating the distal end of the catheter.

[0025] Any feature, structure, or step disclosed herein may be replaced, combined with, or omitted from any other feature, structure, or step disclosed herein. Further, for the purpose of summarizing the disclosure, specific aspects, advantages, and features of the embodiments have been described herein. It will be understood that not all such advantages necessarily result from any particular embodiment disclosed herein. The individual aspects of the disclosure are not essential or indispensable. Further features and advantages of the embodiments will become apparent to those skilled in the art in view of the following "Modes for Carrying Out the Invention", in conjunction with the accompanying drawings and the claims.

Brief Description of the Drawings

[0026]

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[0027] With reference to FIG. 1, a catheter 10 in accordance with one aspect of the present invention is disclosed. Although described primarily in the context of an elongate flexible catheter such as a thrombus embolus retrieval catheter having a single central lumen, the catheter of the present invention can be readily modified to incorporate additional structures such as, for example, a permanent or removable strut strength enhancing mandrel, two or more lumens for enabling the injection of drugs, contrast agents, or perfusion agents, or for supplying an inflation medium to an inflatable balloon carried by the catheter, or combinations of these features, which will be readily apparent to those skilled in the art in view of the disclosure herein. In addition, although the present invention will be described primarily in the context of removing occlusive material from the distal vasculature within the brain, it has applicability as an access catheter for delivering and removing any of a variety of diagnostic or therapeutic devices, with or without aspiration.

[0028] It is contemplated that the catheter disclosed herein will be readily adaptable for use anywhere in the body where it is desirable to position a catheter configured to accurately limit the axial distal advancement of other internal catheter components or tools through the body. For example, the catheter shaft in accordance with the present invention may be sized for use throughout any of the venous or arterial sides of the neurovascular system, the coronary and peripheral vasculature, the gastrointestinal tract, the urethra, the ureters, the fallopian tubes, and other lumens and possible lumens. Specific uses include, for example, thrombus removal in cases such as ischemic stroke, deep vein thrombosis, and pulmonary embolism. The catheter structure of the present invention may also be used for minimally invasive percutaneous tissue access, such as diagnostic or therapeutic access to solid tissue targets (e.g., diagnosis or treatment of the breast or liver or brain), delivery of laparoscopic tools, or access to bone such as the spine for delivery of devices where precise axial control can be advantageous.

[0029] Catheter 10 generally includes an elongated tubular body 16 extending between a proximal end 12 and a distal functional end 14. The length of the tubular body 16 depends on the desired application. For example, lengths in the region from about 120 cm to about 150 cm or more are typical for use in percutaneous transcatheter coronary applications via femoral access. Intracranial or other applications may require different catheter shaft lengths depending on the vascular access site, as would be understood in the art.

[0030] Referring to FIG. 1B, any of the catheters disclosed herein may include an axial restraint device 2402 that cooperates with complementary stoppers on internal components such as a rotating device to allow rotation of the device, but limits the distal axial movement range of the internal device. This enables accurate positioning of the distal tip of the internal device relative to the distal end of the catheter, which is decoupled from the bending of the catheter shaft, and prevents the distal tip of the internal device from extending beyond a preset position such as the distal end of the catheter.

[0031] In the illustrated implementation, the distal restraint device or restraint component 2402 includes at least one protrusion extending radially inward from the inner surface of the tubular body, which is configured to limit the inner diameter of the suction lumen and to provide a bearing surface for engaging a distal surface carried by the agitator. The restraint device may include one or two or three or four or more protrusions such as tabs, or may include a continuous or segmented annular ring providing a substantially continuous annular, proximally facing restraint surface, as illustrated in FIG. 1B. The proximal bearing surface 2405 of the axial restraint device 2402 may be located within a range of about 50 cm or 30 cm or 15 cm from the distal end of the tubular body, for example within a range from about 4 cm to about 12 cm from the distal end.

[0032] Alternatively, the bearing surface 2405 may be provided at the proximal end of the catheter 10, depending on the desired performance and the intended vascular system. For example, the proximal hub 15 may comprise an internal bearing surface 11 that slidably engages a complementary distal bearing surface carried by a core wire. Alternatively, an outer surface 13 carried by the hub 15, such as an annular surface surrounding a central lumen, may be adapted to slidably engage a complementary distal surface carried by a control wire handle discussed below.

[0033] To optimize the alignment of the distal rotatable tip of the internal device with the distal port of the catheter and to decouple its axial alignment from the tortuosity of the vascular path that would otherwise vary the relative axial position of the catheter exit port and the tip, the proximal bearing surface of the axial restraint device is often within the range of about 3 mm to about 50 mm from the distal port of the catheter, in some implementations within the range of about 5 mm to about 20 mm, and in one implementation within the range of about 6 mm to about 14 mm.

[0034] The distal restraint device may be a circular band or ring or protrusion 2402 of metal (e.g., nitinol, stainless steel, aluminum, etc.) or polymer attached to or incorporated within the inner surface of the sidewall of the catheter 2403 near the distal tip, and the distal restraint component 2402 extends within the ID of the catheter. Further, the distal restraint component 2402 may be radiopaque for suitability for visibility under fluoroscopy. The distal restraint component 2402 carries a proximally facing surface 2405, which is, for example, an annular circumferential bearing surface that extends within the inner diameter of the catheter and contacts a distal stopper 2414 on the rotary assembly. See FIG. 1C. For example, the distal stopper 2414 may be an annular feature on the rotary assembly that contacts the distal restraint component 2402 of the catheter to stop distal advancement and prevent displacement of the distal tip beyond the distal tip of the catheter.

[0035] In one implementation, the ring 2402 is C-shaped or cylindrical in its relaxed form before being fixed within the catheter lumen, having a slit that axially extends to form a split ring. The ring 2402 is compressed using a fixing device that contracts the ring into a closed circular shape such that the ring can slide within the catheter (e.g., 0.071 inches). When the ring is released from the fixing device, the ring radially expands to the maximum diameter allowed by the inner diameter of the catheter. The radial force of the ring engages the inner surface of the catheter and resists axial displacement under the applied force in the intended use. In another implementation, the ring is a completely closed continuous annular structure (such as a typical marker band), and its distal end flares slightly radially outward to form a locking edge. The ring is inserted into the catheter from the distal end. When an axial force is applied from the proximal side, the flared portion with the locking edge holds the ring in place.

[0036] Alternatively, the distal restraint device may be formed by creating radially inward-facing folds in the catheter body or by introducing a bearing surface that penetrates the wall of the catheter and communicates with the central lumen, for example, by introducing at least one or two or more protrusions that penetrate the wall and enter the lumen. The restraint device may take the form of a concentric inner tube having an axial length of at least about 1 mm or 2 mm or more, but generally less than about 5 cm or 3 cm or 2 cm. Depending on the nature of the distal restraint device, it may be fixed by a bond formed by any of various bonding techniques including mechanical interference fits, friction fits, or adhesive and thermal bonding.

[0037] Referring to FIGS. 1C and 1D, the inner member takes the form of a blood clot retrieval device 2401. The distal section 2407 of the rotatable core wire includes a torque coil 2412 that surrounds the core wire 2410. The torque coil 2412 includes an outer coil 2413 that concentrically surrounds an inner coil 2415 having windings in opposite directions. The coil 2412 is shown as having a constant diameter, but this leaves an internally captured space between the coil and the core wire as a result of the tapered core wire. The diameter of the coil 2412 can be tapered smaller in the distal direction to follow the taper of the core wire to optimally maximize the area of the suction lumen between the coil and the inner wall of the corresponding catheter. This can be achieved by winding the coil around the core wire functioning as a tapered mandrel or by using other techniques known in the art. When this is done, the OD of the core wire tapers smaller in the distal direction while the area of the suction lumen tapers larger in the distal direction.

[0038] At the proximal end of the core wire 2410, a handle is provided that is configured to manually rotate the core wire. The handle may be a molded component such as a knob having an axially oriented surface structure such as a ridge, flat portion, or groove to enhance gripping. The handle may have two opposing tabs that extend in opposite directions from the axis of the core wire and can be rotated using two or three fingers.

[0039] As further illustrated in FIGS. 1E and 1F, the torque coil 2412 extends between a proximal end 430 and a distal end 432. The proximal end 430 is secured to the tapered portion of the core wire 2410. As illustrated in FIG. 1E, the core wire 2410 is tapered from the larger diameter within the proximal zone to the smaller diameter within the distal zone 434, with a distal transition 436 between the tapered section and the distal zone 434 which may have a substantially constant diameter throughout. The inner diameter of the inner coil 2415 is complementary (approximately the same) to the outer diameter at the proximal end 430 of the core wire 2410. The tapered section of the core wire 2410 extends proximally from the distal transition 436 to a proximal transition (not shown) where the core wire 2410 has a constant diameter.

[0040] The torque coil 2412 may additionally include a proximal radiopaque marker and / or connector, such as a solder joint 438. In the illustrated implementation, the proximal connector 438 is in the form of an annular band of silver solder, surrounding the inner coil 415 and abutting the proximal end of the outer coil 2413.

[0041] The axial length of the torque coil 2412 is in the range of from about 10 mm to about 50 mm, and in some embodiments is in the range of from about 20 mm to about 40 mm. The distal transition 436 and the distal stopper 2414 may be positioned within the range of from about 5 mm to about 20 mm from the proximal end of the distal cap 2420, and in some implementations within the range of from about 8 mm to about 12 mm.

[0042] Referring to FIGS. 1E - 1I, the distal stopper 2414 may comprise one or two or three or more spokes 440 extending radially outwardly from the outer coil 413 and optionally may be supported by an annular hub 442 carried by the torque coil 2412. The spokes 440 support a slider 441 having a peripheral surface 442 configured to slidably fit within the inner diameter of the delivery catheter lumen. Preferably, at least three or four or five or more spokes 440 are equidistantly spaced for rotational balance. In the illustrated embodiment, three spokes 440 are spaced approximately 120° apart about the circumference of the torque coil 2412.

[0043] In the illustrated embodiment, the spoke or strut 440 has an axial length greater than its width measured circumferentially and extends parallel to the longitudinal axis of the catheter. Alternatively, the spoke 440 can be oriented in a helical configuration to form a propeller that can assist in the proximal transport of material during rotation. The leading edge may be sharpened to cut a thrombus engaged by the rotation of the core wire while simultaneously applying a vacuum to the central lumen.

[0044] The distal stopper 2414 carries, for example, a plurality of distal surfaces 446 on the slider 441. The distal surfaces 446 are configured to slidably engage a proximal surface of a stop device on the inner diameter of the delivery catheter, for example, a proximal facing surface 2405 on an annular flange or ring 2402 extending radially inwardly. See FIG. 1B previously discussed. This creates a sliding interference fit with the bearing surface such that the distal stopper 2414 can rotate within the delivery catheter and can move axially distally to the same or prior to the case where the distal surface 446 slidably engages the proximal surface 2405 on the stop ring 2402.

[0045] Referring to FIG. 1E, the distal end 432 of the torque coil 2412 includes a distal cap 2420. The distal cap 2420 may include an annular band, such as a radiopaque marker band, that is adhered to the outer surface of the inner coil 2415 and is axially distal and adjacent to or overlapping the distal end of the outer coil 2413. A proximally extending appendage, such as an annular flange 2417, may be provided on the agitator tip 2416, which is for coupling to the distal cap 2420 and, in the illustrated embodiment, for coupling to the outer coil 2413. The distal cap 2420 may also be coupled directly or indirectly to the distal end of the core wire 2410.

[0046] The agitator tip 2416 includes a distal end 450 and a helical flange 452 that extends proximally, increasing in diameter in the proximal direction to a maximum diameter and then decreasing in diameter in the proximal direction to a minimum diameter that may be larger than the diameter at the distal end. The flange may extend around an extension of the longitudinal axis of the core wire 2410 for at least one substantially full rotation and generally less than about 5 or 4 or 3 rotations. The helical flange includes a rounded and blunted edge 454 that is configured to rotate slidably within a tubular delivery catheter.

[0047] The maximum OD of the distal end 2416, when measured at the axial operating location of the distal end 2416 with the stopper 2414 engaged with the stop ring, is generally at least about.005 inches, preferably at least about 0.01 inches or 0.015 inches or more smaller than the ID of the catheter suction lumen intended to be advanced through the embolization treatment system 2401. For example, a distal end having a maximum OD in the range of about 0.050 to about 0.056 inches will be positioned within a catheter having a distal ID in the range of about 0.068 to about 0.073 inches and, in one embodiment, about 0.071 inches. With the distal end centered within the lumen of the delivery (suction) catheter, this distal end is spaced from the inner wall of the catheter by at least about 0.005 inches and, in some embodiments, at least about 0.007 inches or 0.010 inches or more in all directions.

[0048] Thus, an unobstructed flow path is formed in the annular space between the maximum OD of the distal end and the ID of the catheter lumen. This annular flow path, in cooperation with the vacuum and the helical distal end, grips and withdraws occlusive material within the catheter under rotation and vacuum. The annular flow path is significantly larger than any flow path created by manufacturing tolerances at the distal end configured to shear the embolic material between the distal end and the catheter wall.

[0049] An additional suction volume results from the helical communication path defined between each two adjacent thread forms of the distal end. The cross-sectional area of the helical flow path of a distal end having a maximum OD in the range of about 0.050 inches to about 0.056 inches is generally at least about 0.0003 square inches, at least about 0.00035, or at least about 0.000375 inches in some embodiments. Thus, the total suction flow path spanning the helical distal end is the sum of the helical flow path through the distal end and the annular flow path defined between the OD of the distal end and the ID of the catheter lumen.

[0050] The rounded edge 454 on the thread shape 452, the slow manual rotation of the tip through less than about 20 rotations, or less than about 10 rotations, or less than about 5 rotations, and the space between the thread shape 452 and the catheter inner wall are combined so that both suction through the helical communication path formed between adjacent helical thread shapes and suction around the outside of the tip 2416 are possible. This suction is made such that the assembly is configured to engage and capture the occluding substance, but not shear the occluding substance between the sharp edge and the catheter inner wall. Once engaged, further applied rotation pulls the suction catheter distally past the blood clot, fixing the proximal portion of the blood clot and facilitating proximal retraction and removal. The axial length of the tip 2416 including the attachment sleeve 2417 is generally less than about 6 mm, and preferably less than about 4 mm, or 3 mm, or 2.5 mm or less, depending on the desired performance.

[0051] The pitch of the thread shape 452 may generally be varied within a range of about 35 degrees to about 80 degrees, depending on the desired performance. A thread shape pitch within the range of about 40 degrees to about 50 degrees may work best for a hard blood clot, while a pitch within the range of about 50 degrees to about 70 degrees may work best for a soft blood clot. In some implementations, the pitch is within the range of about 40 degrees to about 65 degrees, or within the range of about 40 degrees to about 50 degrees.

[0052] The distal end 2416 may additionally have features for attracting and / or enhancing the adhesion of blood clots to the distal end. For example, by treating the material of the distal end or applying a coating, a texture such as a microporous, microgranular, nanoporous, or nanoparticulate surface may be provided on the distal end. A coating of a component that attracts blood clots, such as a polymer or a drug, may be adhered to the surface of the distal end. For example, a coating of roughened polyurethane (Tecothane, Tecoflex) may be adhered to at least the threaded surface and optionally to the entire distal end. The polyurethane may preferably be roughened after coating, for example by solvent treatment, and the adhesion of the coating to the distal end may be enhanced by roughening the surface of the distal end prior to coating.

[0053] Alternatively, the core wire 2410 may be provided with an insulating coating, whereby the propagation of negative charge is delivered to the distal end, enabling the attraction of blood clots. Two conductors may, for example, take a coaxial configuration and extend over the entire length of the body. Energy parameters and considerations are disclosed in U.S. Patent No. 10,028,782 to Orion and U.S. Patent Publication No. 2018 / 0116717 to Taff et al., each of which disclosures is hereby expressly incorporated by reference in its entirety. As a further alternative, the distal end 2416 may be cooled to cryogenic temperatures to create a small freeze adhesion between the distal end and the blood clot. Considerations for forming a small cryogenic distal end for an intravascular catheter are disclosed in U.S. Patent Publication No. 2015 / 0112195 to Berger et al. and 2018 / 0116704 to Ryba et al., each of which disclosures is hereby expressly incorporated by reference in its entirety.

[0054] Referring to FIG. 1G, a cross-section through the distal stopper 2414 is shown, in which the slider 441 is a continuous circumferential wall having a continuous peripheral bearing surface 442. Three struts 440 are spaced apart, defining three flow passages 443 that extend axially therethrough. The sum of the surface areas of the leading edges of the struts 440 is preferably minimized as a percentage of the sum of the surface areas of the open flow passages 443. This allows for the maximum area for suction while at the same time providing sufficient axial support for the distal surface 446 (see FIG. 1F) to engage a complementary stop surface on the inner wall of the catheter and to prevent the tip 2416 from advancing distally beyond a preset relationship with the catheter. The sum of the leading (distally facing) surface areas of the struts is generally less than about 45% of the sum of the areas of the flow passages 443, typically about 30%, or 25%, or less than 20%.

[0055] In an embodiment having a torque coil 2412 with an OD of about 0.028 inches, the OD of the stopper 2414 is about 0.068 inches. The wall thickness of the struts is generally less than about.015 inches, typically less than about 0.010 inches, and in some implementations less than about 0.008 inches, or 0.005 inches or less. The struts 440 may have a catheter axial length sufficient to support the assembly against distal movement beyond the catheter stop ring and may be at least about 50% of the OD of the stopper 2414. For a stopper 2414 having an OD of about 0.68 inches, the struts 2440 have an axial length of at least about 0.75 mm, or 0.95 mm.

[0056] Referring to FIG. 1H, a stopper 2414 is illustrated having three different sliders 441 each supported by a respective post 440. The sum of the circumferential portions of the three peripheral surfaces is preferably 75% or less, and in some implementations 50% or 40% or less, of the total circumference of the continuous circumferential peripheral surface 442 as shown in FIG. 1G. This further increases the cross-sectional area of the flow path 443. For a catheter having a hub 443 with an ID of about 0.07 inches or less and an OD of at least about 0.026 or 0.028 or 0.030 or more, the sum of the flow paths 443 is at least about 0.0015 inches, preferably at least about 0.020 or 0.022 inches or more. The area of the leading edge of the post 440 and the slider 441 is preferably less than about.003 inches, more preferably less than about 0.001 inches, or 0.0008 inches or less. In the catheter axial direction, the length of the post 440 is at least about 0.50 mm or 0.75 mm, and in one embodiment, the length of the post 440 and the slider 441 is about 1 mm.

[0057] One method for using the above system is described below. Introduce a.088 LDP guide catheter and, if possible, advance it until the catheter tip is slightly proximal towards the occlusion site. Introduce the.071 aspiration catheter of FIGS. 1A and 1B through the 088 LDP and advance it until the catheter tip reaches the thrombus surface. Remove any intermediate catheter or guide wire if applicable. Introduce a rotatable core wire such that its distal tip is flush with the distal end of the.071 aspiration catheter. Seal the proximal RHV and apply vacuum to the.071 aspiration catheter using a suction pump. Manually rotate the core wire between about 2 and 10 times, generally 20 times or less, to engage without cutting the thrombus, pull the catheter distally partially beyond the thrombus, and stop rotation of the core wire.

[0058] At this point, the aspiration catheter is secured to the thrombus using both vacuum and mechanical engagement. The.088LDP guide catheter is advanced over the aspiration catheter until the 0.088 catheter reaches the surface of the thrombus, with the aspiration catheter functioning like a guide wire. A vacuum source, such as a VacLok syringe, is used to apply vacuum to the 088LDP guide catheter. The aspiration catheter with the thrombus secured at its distal end is retracted proximally through the 088LDP guide while maintaining the position of the 088LDP at the occlusion site.

[0059] If flow has not resumed through the 088LDP, the core wire may be removed from the aspiration catheter. Optionally, the helical tip of the core wire may be wiped to remove residual thrombus, and the core wire and aspiration catheter may be returned to the occlusion site and the thrombus retrieval procedure repeated until flow resumes. Once flow has resumed, the.088LDP guide catheter is removed.

[0060] In accordance with another aspect of the present invention, a torque transmission system is provided for changing the rotational orientation of the distal end of a highly flexible catheter shaft. Certain highly flexible catheters, as further discussed in relation to, for example, FIG. 7E, have an elliptical opening that is cut to have an angled tip at the distal end. One feature of the angled tip is that it aids in navigation and aspiration of thrombus. Ideally, this cut with the angled tip is oriented such that the large elliptical opening created faces the thrombus as directly as possible, even in a vascular system with bends and bifurcations. Generally, neurovascular catheters, and particularly the distal wall structures disclosed herein, have poor torque transmission performance, such that rotating the proximal end of the catheter does not result in an equivalent degree of predictable rotation at the distal end due to the flexible structure and thin walls. Therefore, it is not practical to attempt to orient the angled tip by applying torque directly to the catheter from the proximal end.

[0061] Referring to FIG. 2A, a torque wire is provided that directly transmits torque to the distal zone of the catheter. A distal stopper 2414, such as a circular ring, is attached to the core wire in the same manner as discussed in connection with FIG. 1C. The portion of the core wire 2410 that extends beyond about the distal transition 436 (see FIG. 1E) may be omitted, leaving the distal stopper 2414 at the distal end of the torque wire. Alternatively, a short leading segment of the core wire may extend distally beyond the distal stopper 2414 as a centering guide. The distal stopper 2414 carries a distal face that carries at least one, generally at least two or three or more engaging elements 2415 for rotationally engaging a complementary engaging structure within the catheter lumen.

[0062] Referring to FIGS. 2B and 2C, the catheter tubular body 16 carries a distal restraint device 2402 as previously discussed. The proximal face includes at least a second engaging structure 2417 that rotationally engages at least a first engaging structure 2415 on the distal face of the distal stopper. In FIGS. 2A and 2B, the engaging structures are complementary interlocking ramped teeth that allow the distal face 2415 formed at the distal end of the torque-operable guide wire and the proximal face of the distal restraint device 2402 to engage and lock together. This provides a mechanical connection that transmits torque and rotates the catheter in response to rotation of the wire.

[0063] In the embodiments of FIGS. 2A and 2B, the engaging components include a projecting portion that axially extends distally and has a first surface 2419 that extends substantially parallel to the longitudinal axis of the wire and an opposing inclined surface 2421 that extends at an inclination angle of at least about 15 or 20 degrees or more with respect to the longitudinal axis. The complementary projections and intervening recesses on the stop ring engage when the wire is rotated in a first direction and rotate the stop ring in response, but when the wire is rotated in a second, opposite direction, they may ride over each other and prevent the catheter from rotating in response to rotation of the wire.

[0064] The configuration of FIG. 2B may be integrated into any of the systems of FIGS. 1A - 1H. This enables the wire to be rotated in a first direction, allowing the catheter to be rotated within the blood vessel and to a desired rotational position adjacent to the occlusion. Thereafter, the wire may be rotated in a second, opposite direction to rotate the distal tip 2416, and as described above, the occlusion may be engaged to facilitate removal.

[0065] Alternatively, these complementary engagement surfaces may be bidirectional, engaging in either rotational direction, for example at least one protrusion on the wire that engages at least one recess on the catheter. In the illustrated embodiment, the engagement structure 2415 includes at least one toothed portion with a square edge that rotatably engages a corresponding recess such as an axially extending elongate groove. (See, for example, FIG. 3B). This enables the catheter to be coupled and rotated in either direction.

[0066] Alternatively, either or both of the complementary engagement surfaces carried by the distal stopper 2414 and the distal restraint device 2402 may have features that enhance friction, which may be, for example, a textured surface, or material, or coating, having a friction that is sufficiently high to transmit from the core wire to the catheter body sufficient torque to rotate the distal end of the catheter and effect a change in direction, such that this change in direction, for example, enters or avoids a lateral branch, or presents a different relationship between the catheter and the occluding substance.

[0067] If the angular orientation of the thrombus and the catheter (see FIG. 7E) is not favorable for presenting the largest opening of the catheter directly towards the clot, the wire may be advanced relative to the internal stop ring of the catheter and the complementary engagement surfaces engaged, such that torque is supplied using the wire to reorient the distal end of the catheter by rotation to be more favorable for clot aspiration.

[0068] In addition, while the catheter is advancing distally through the tortuous vasculature, the tip of the catheter may be rotated to optimize the angular orientation of the angled tip to facilitate distal advancement of the catheter. Thus, the angled catheter tip can be precisely rotated so as not to be caught by arterial bifurcations or calcium deposits.

[0069] In the implementation illustrated in FIG. 3A, a torque wire, such as thrombus retrieval device 2401, is similar to that illustrated in FIG. 1C except that there is no distal stopper 2414. In this implementation, the thrombus retrieval device can pass through the lumen of the outer catheter 2403 and be axially advanced freely beyond the distal end of the catheter. The thrombus retrieval device 2401 can be advanced distally to engage the thrombus, and the outer catheter 2403 can be advanced distally over the wire while having a pulling force on the thrombus retrieval device and optionally applying a vacuum through the catheter 2403 to grip and remove the thrombus.

[0070] Alternatively, the helical tip 450 can be rotated into and optionally through the occluding thrombus so as to function as a locking portion on the wire. The catheter 2403 may be withdrawn proximally leaving the locked core wire 2410 in place. The core wire 2410 can then be used as a guide wire to guide other interventional devices over or along the wire to reach the occlusion and perform additional functions. The core wire 2410 may comprise an elongate central lumen extending between a proximal port at the proximal end and a distal port at the distal tip 450. Following placement of the distal tip, a guide wire may be advanced through the central lumen and, if the distal tip 450 has rotated distally that far, through the thrombus. Thereafter, the tip 450 and the core wire 2410 may be rotated counterclockwise to disengage from the occlusion and withdrawn proximally from the patient, leaving the guide wire in place for subsequent procedures.

[0071] In an alternative configuration, the catheter 2403 may include a second lumen that is for perfusion, aspiration, or receiving a guide wire therethrough and that extends axially from the proximal port to the distal end 14 or a distal opening in its vicinity. At a desired point in the procedure, the helix and catheter 2403 may be withdrawn proximally, leaving the guide wire in place for further access.

[0072] In the implementations illustrated in FIGS. 3B and 3C, the torque wire and complementary catheter are configured in the same manner as FIGS. 1A-1H, except that the distal tip 450 may extend a controlled distance slightly beyond the distal end 14 of the catheter 10. In FIG. 3B, the distal tip 450 is approximately axially aligned with the distal end 14 of the catheter 10 (or the distal tip 3132 in FIG. 6E). This leaves an axial gap 18 between the complementary stop surface on the axial restraint device 2404 and the distal stopper 2414. As illustrated in FIG. 3C, by contacting the complementary stop surface, it is possible to extend the distal tip 450 outside the catheter by a maximum of the distance 18. The distance 18 may be at least about.5 mm or about 1 mm or 2 mm, but may generally be about 1.5 cm or 1 cm or 0.5 cm or less, depending on the desired functionality. In some embodiments, the distance 18 is in the range of about 0.5-3 mm.

[0073] Alternatively, the maximum distal extension distance 18 may be related to the pitch of the helical thread shape. For example, 18 may be a distance equivalent to the axial length for about 1 to about 5 rotations of the thread shape, and preferably may be within the range of about 1 to about 3 rotations of the thread shape.

[0074] In use, the distal tip 450 of the system of FIGS. 3B and 3C can extend beyond the catheter and be rotated to engage the plug. When the helix rotates, it pulls the catheter forward (distally), allowing the helix to advance further distally over the core wire.

[0075] A further use of the distal stopper on the wire structure is illustrated in FIG. 4. Since the core wire 2410 extends only distally up to approximately transition 436 (FIG. 1E), the distal stopper is always present at the distal end of the wire. The distal surface 2411 on the distal stopper 2414 can be used to strike the proximal surface 2405 on the distal restraint device 2402 (see FIG. 1B) to provide a jack hammer effect, such that instead of pushing the catheter from the proximal end, it can be pulled from the distal end. The striking can be at a low frequency manually achieved by the clinician, depending on the catheter configuration and the desired clinical result, or at a high frequency such as at least about 10 Hz or 100 Hz or ultrasonic.

[0076] With this configuration, at least from the perspective of pushability, the required value of the column strength along the length of the catheter body may decrease. Maintaining hoop strength is still desirable for catheters intended to be placed under vacuum. However, in a non-vacuum device, if the catheter can reach the target site by "pulling" the catheter distally from the distal restraint device 2402 rather than pushing from the proximal manifold, there is a possibility that the sidewall of the catheter can be reduced.

[0077] Referring to FIGS. 5A and 5B, a side elevation view of a blood flow-supported access wire for use with a catheter having a stop ring is illustrated. The wire 2410 carries a stopper 2414 that limits distal movement of the wire relative to the catheter by interference fit with the stop ring 2402 as previously discussed. A force transfer component 2440 is carried by the wire 2410 and is configured to move between a radially contracted configuration (FIG. 5A) for positioning within the catheter and a radially expanded configuration (FIG. 5B) when advanced distally out of the catheter. The force transfer component 2440 is adapted to at least partially impede blood flow and to transfer a distally directed force to the wire 2410. Responsive distal downstream advancement of the force transfer component 2440 causes the stopper 2414 to engage the stop ring 2402 and the catheter to be pulled in the forward direction.

[0078] In the illustrated implementation, the force transfer component 2440 includes a conical membrane such as a filter having an open proximal end 2442 and a closed distal end 2444. The proximal opening 2442 may be supported by a nitinol wire loop that is connected to the wire 2410 by angled struts 2446. The angled struts 2446 facilitate re-entry of the force transfer component 2440 into the distal end of the catheter upon proximal withdrawal of the wire 2410.

[0079] In an alternative implementation of the invention, the force transfer component 2440 may include an alternative structure for capturing force from the blood flow, including an inflatable balloon. The wire 2410 may comprise a central lumen extending along its length and communicating with the balloon to achieve inflation and deflation as understood in the art.

[0080] Referring to FIGS. 5C - 5E, a wire 2410 having an operable distal region 2450 is illustrated. The manipulation region 2450 may include a tubular body having a first side surface 2452 that is relatively axially non - contractile. The second, typically opposing side, is provided with a plurality of transverse elongate grooves 2454 that permit axial contraction. A pull wire 2456 is attached to the distal end of the manipulation zone 2450. As the pull wire 2456 retreats proximally relative to the tubular body, axial contraction and as a result, curvature of the transverse elongate grooves 2454 occurs as shown in FIG. 5E.

[0081] Any catheter shaft, or portion of a catheter shaft, in accordance with the present invention may include a multi - layer structure that is highly flexible and has a high degree of pushability sufficient to reach deep into the cerebrovascular system, for example, at least to the conus, cavernous, or cerebral segments of the internal carotid artery (ICA).

[0082] In one example, referring to FIG. 7A, the catheter 3000 may have an effective length from the manifold to the distal tip of from about 70 cm to about 150 cm, from about 80 cm to about 140 cm, from about 90 cm to about 130 cm, from about 100 cm to about 120 cm, or from about 105 cm to about 115 cm. The outer diameter of the catheter 3000 may be from about 0.07 inches to about 0.15 inches, from about 0.08 inches to about 0.14 inches, from about 0.09 inches to about 0.13 inches, from about 0.1 inches to about 0.12 inches, or from about 0.105 inches to about 0.115 inches, and the distal section may be smaller than the proximal section. The inner diameter 3108 of the catheter 3000 in a single central lumen embodiment may be about 0.11 inches or greater, about 0.1 inches or greater, about 0.09 inches or greater, about 0.088 inches or greater, about 0.08 inches or greater, about 0.07 inches or greater, about 0.06 inches or greater, or about 0.05 inches or greater. The inner diameter 3108 of the catheter 3000 in a single central lumen embodiment may be about 0.11 inches or less, about 0.1 inches or less, about 0.09 inches or less, about 0.088 inches or less, about 0.08 inches or less, about 0.07 inches or less, about 0.06 inches or less, or about 0.05 inches or less.

[0083] Referring to FIG. 7A, the inner liner 3014 may be formed by dip coating a mandrel (not shown) to provide a thin-walled, tubular inner layer of the catheter body 3000. The dip coating may be produced by coating a wire, such as a silver-coated copper wire, in PTFE. The mandrel may then be axially stretched to reduce the diameter and removed leaving the tubular inner liner.

[0084] Subsequently, the outer surface of the tubular inner liner 3014 may then be coated with a soft bundling layer 3012 such as polyurethane (e.g., Tecoflex (trademark)) to produce a layer having a thickness of about 0.005 inches or less, and in some implementations approximately 0.001 inches. The bundling layer 3012 will generally extend along approximately the most distal 10 cm or 20 cm, and generally less than about 50 cm of the catheter shaft 3000, and in one implementation may extend approximately distally 30 cm of the catheter shafts 3000, 3100.

[0085] Subsequently, a braid such as a 75 ppi stainless steel braid 3010 may be wrapped around the inner liner 3014 through the proximal zone to the distal transition 3011. Subsequently, a coil 3024 including a shape memory material such as nitinol alloy may be wrapped around the inner liner 3014 from the distal transition 3011 to the distal end of the catheter 3000. In one implementation, the nitinol coil has a transition temperature below body temperature such that the nitinol remains in the austenite (springy) state at body temperature. The adjacent annular structures or threads of the coil 3024 may be tightly wound in the proximal zone and may be more loosely spaced between adjacent annular structures in the distal section. In embodiments having a coil section 3024 with an axial length between at least about 20% and about 30% of the total length of the catheter (e.g., a 28 cm coil length for a 110 cm catheter shaft 3000), at least 1, or 2, or 3, or 4 cm of the distal coil will have a spacing of at least about 130% of the spacing in the proximal coil section, and in some implementations at least about 150% or more. For a 110 cm catheter shaft 3000 with a nitinol coil, the spacing in the proximal coil may be about 0.004 inches, and in the distal section may be at least about 0.006 inches, or 0.007 inches or more.

[0086] In embodiments including an extension catheter, the distal extensible section of the catheter may be configured according to the foregoing. The length of coil 3024 may be proportional to the length of the extensible catheter section or the overall length of catheter 3000 (e.g., the extended length). Coil 3024 may extend from the distal end of the extensible section over at least about 50%, about 60%, about 70%, about 80%, or about 90% of the length of the extensible section. In some embodiments, catheter 3000 or the extensible section may not include braiding, and coil 3024 may extend to the proximal end (100% of the length) of the extensible section.

[0087] The distal end of coil 3024 can be spaced proximally from the distal end of inner liner 3014, for example, to provide room for an annular radiopaque marker 3040. Coil 3024 may be positioned proximally from the distal end and, in some embodiments, drawn in by approximately 1 cm, 2 cm, or 3 cm or less. In one embodiment, the distal end of catheter 3000 includes an angled distal face 3006 that lies in a plane having an angle of at least about 10°, or about 20°, and in one embodiment about 30° with respect to the longitudinal axis of catheter 3000. The radiopaque marker 3040 may lie in a plane transverse to the longitudinal axis. Alternatively, at least the distally facing edge of the annular radiopaque marker 3040 may be elliptical and lie in a plane that is angled with respect to the longitudinal axis and complementary to the angle of inclination of the distal face 3006. Further details are described in connection with FIG. 7E below.

[0088] After attaching the proximal braid 3010, the distal coil 3024, and the RO marker 3040, an outer jacket 3020 such as a shrink-wrap tube may be attached to surround the catheter body 3000. The outer shrink-wrapped sleeve 3020 may comprise any of a variety of materials such as polyethylene, polyurethane, polyether block amide (e.g., PEBAX™), nylon, or others known in the art. By applying sufficient heat, the polymer is caused to flow into and embed within the proximal braid and the distal coil.

[0089] In one implementation, the outer shrink-wrap jacket 3020 is formed by successively advancing a plurality of short tubular segments 3022, 3026, 3028, 3030, 3032, 3034, 3036, 3038 concentrically over a partial assembly of the catheter shaft and applying heat to shrink those segments onto the catheter 3000 to provide a smooth, continuous outer tubular body. The structure may extend along at least the most distal 10 cm of the catheter body 3000, and preferably along at least the most distal about 20 cm, 25 cm, 30 cm, 35 cm, 40 cm, or greater than 40 cm in length. The overall length of the outer shrink-wrap jacket 3020 may be formed from the tubular segments, and the length of the distal tubular segments (e.g., 3022, 3026, 3028, 3030, 3032, 3034, 3036, 3038) may be shorter than one or more of the tubular segments forming the proximal portion of the outer shrink-wrap jacket 3020 to provide a more abrupt flexibility transition toward the distal end of the catheter 3000.

[0090] The durometer of the outer wall segment may decrease in the distal direction. For example, the proximal segments such as 3022 and 3026 may have a durometer of at least about 60 or 70 D, and the durometer of successive segments gradually decreases distally to a durometer of about 35 D or less than 25 D. The 25 cm section may have at least about 3 or 5 or 7 or more segments, and the entire catheter 3000 may have at least about 6 or 8 or 10 or more distinct flexibility zones. The distal one or two or four or more segments 3036, 3038 may have a smaller post-shrink OD than the more proximal segments 3022 - 3034, thereby creating a decreasing OD along the completed catheter body 3000. The length of the lower OD section 3004 may be in the range of about 3 cm to about 15 cm, and in some embodiments, in the range of about 5 cm to about 10 cm, such as about 7 or 8 cm, and may be achieved by providing a lower wall thickness in the distal segments 3036, 3038.

[0091] Referring to FIGS. 7B and 7D, the catheter may further include a tension support that increases tension resistance in the distal zone. The tension support may include filaments, and more particularly, may include one or more axially extending filaments 3042. The one or more axially extending filaments 3042 may be axially disposed within the catheter wall near the distal end of the catheter. The one or more axially extending filaments 3042 act as a tension support and resist elongation of the catheter wall under tension (e.g., when the catheter is retracting proximally through a tortuous vascular system).

[0092] At least one of the one or more axially extending filaments 3042 may extend proximally along the length of the catheter wall from a location about 1.0 cm from the distal end of the catheter to less than about 5 cm from the distal end of the catheter, less than about 10 cm from the distal end of the catheter, less than about 15 cm from the distal end of the catheter, less than about 20 cm from the distal end of the catheter, less than about 25 cm from the distal end of the catheter, less than about 30 cm from the distal end of the catheter, less than about 35 cm from the distal end of the catheter, less than about 40 cm from the distal end of the catheter, or less than about 50 cm from the distal end of the catheter.

[0093] The one or more axially extending filaments 3042 may have a length of about 50 cm or more, about 40 cm or more, about 35 cm or more, about 30 cm or more, about 25 cm or more, about 20 cm or more, about 15 cm or more, about 10 cm or more, or about 5 cm or more.

[0094] At least one of the one or more filaments 3042 extending in the axial direction may have a length of about 50 cm or less, about 40 cm or less, about 35 cm or less, about 30 cm or less, about 25 cm or less, about 20 cm or less, about 15 cm or less, about 10 cm or less, or about 5 cm or less. At least one of the one or more filaments 3042 extending in the axial direction may extend to at least about 50 cm from the distal end of the catheter, at least about 40 cm from the distal end of the catheter, at least about 35 cm from the distal end of the catheter, at least about 30 cm from the distal end of the catheter, at least about 25 cm from the distal end of the catheter, at least about 20 cm from the distal end of the catheter, at least about 15 cm from the distal end of the catheter, at least about 10 cm from the distal end of the catheter, or at least about 5 cm from the distal end of the catheter.

[0095] In some implementations, the filament extends proximally from the distal end of the catheter along the length of the coil 24 and terminates proximally within a range of about 5 cm or 2 cm or less on either side of the transition 3011 between the coil 3024 and the braid 3010. The filament may terminate at the transition 3011 without overlapping the braid 3010.

[0096] In another embodiment, the distal portion of the catheter 3000 may include a durometer of less than approximately 35D (e.g., 25D) to form a highly flexible distal portion of the catheter, and may have a length between approximately 25 cm and approximately 35 cm. The distal portion may include one or more tubular segments (e.g., segment 3038) of the same durometer. A series of tubular segments adjacent proximally may form a transition region between the proximal rigid portion and the distal highly flexible portion of the catheter 3000. The series of tubular segments forming the transition region may have the same or substantially similar lengths, e.g., a length of approximately 1 cm.

[0097] The relatively short length of a series of tubular segments may result in a steep drop in durometer across the transition region. For example, the transition region may have a proximal tubular segment 3036 (proximally adjacent to the distal portion) having an approximately 35D durometer. The adjacent proximal segment 3034 may have an approximately 55D durometer. The adjacent proximal segment 3032 may have an approximately 63D durometer. The adjacent proximal segment 3030 may have an approximately 72D durometer.

[0098] Even more proximal segments may include a durometer greater than approximately 72D and may extend to the proximal end of the catheter or extension catheter segment. For example, the extension catheter segment may include a proximal portion greater than approximately 72D between about 1 cm and about 3 cm. In some embodiments, the proximal portion may be about 2 cm in length. In some embodiments, the most distal segments (e.g., 3038 - 3030) may include Pebax (PEBAX (trademark)), and even more proximal segments may generally include a stiffer material, such as Vestamid (registered trademark).

[0099] The inner diameter of the catheter 3000 or catheter extension segment may be between approximately 0.06 inches and 0.08 inches, between approximately 0.065 inches and 0.075 inches, or between 0.068 inches and 0.073 inches. In some embodiments, the inner diameter is approximately 0.071 inches.

[0100] In some embodiments, the distal portion may have a tapered inner diameter as described elsewhere herein. This taper may occur approximately between the highly flexible distal portion and the transition region (e.g., across the proximal portion of the highly flexible distal portion). The taper may be relatively gradual (e.g., occurring over approximately 10 cm or more) or relatively steep (e.g., occurring over approximately less than 5 cm). The inner diameter may taper to an inner diameter between approximately 0.03 inches and approximately 0.06 inches. For example, the inner diameter may be approximately 0.035 inches, approximately 0.045 inches, or approximately 0.055 inches at the distal end of the catheter 3000. In some embodiments, the inner diameter may be constant at least over the catheter extension section.

[0101] In some embodiments, the coil 3024 may extend proximally from the distal end of the catheter 3000 along the highly flexible distal portion and terminate at the distal end of the transition region. In other embodiments, the coil 3024 may extend proximally from the distal end of the catheter to the proximal end of the transition region, to a point along the transition region, or beyond the transition region. In other embodiments, the coil 3024 may extend over the entire length of the catheter 3000 or the catheter extension section as described elsewhere herein. The braid 3010, if present, may extend from the proximal end of the coil 3024 to the proximal end of the catheter 3000 or the catheter extension section.

[0102] One or more axially extending filaments 3042 may be disposed near or radially outside the braiding layer 3012 or the inner liner 3014. One or more axially extending filaments 3042 may be disposed near or radially inside the braid 3010 and / or the coil 3024. One or more axially extending filaments 3042 may be carried between the inner liner 3014 and the helical coil 3024.

[0103] When one or more filaments 3042 extending in the axial direction are disposed within the catheter wall, the filaments 3042 extending in the axial direction may be arranged symmetrically in the radial direction. For example, the angle between two filaments 3042 extending in the axial direction with respect to the radial center of the catheter may be about 180 degrees. Alternatively, depending on the desired clinical performance (e.g., flexibility, trackability), the filaments 3042 extending in the axial direction may be arranged to be asymmetric in the radial direction. The angle between any two filaments 3042 extending in the axial direction with respect to the radial center of the catheter may be less than about 180 degrees, less than or equal to about 165 degrees, less than or equal to about 150 degrees, less than or equal to about 135 degrees, less than or equal to about 120 degrees, less than or equal to about 105 degrees, less than or equal to about 90 degrees, less than or equal to about 75 degrees, less than or equal to about 60 degrees, less than or equal to about 45 degrees, less than or equal to about 30 degrees, less than or equal to about 15 degrees, less than or equal to about 10 degrees, or less than or equal to about 5 degrees.

[0104] One or more filaments 3042 extending in the axial direction may be made of materials such as Kevlar, polyester, Meta-Para-Aramide, or any combination thereof. At least one of the one or more filaments 3042 extending in the axial direction may include a single fiber or a bundle of multiple fibers, and the fiber or bundle may have a circular or rectangular cross-section. The terms fiber or filament do not convey composition and may include any of a variety of high-tensile polymers, metals, or alloys depending on design considerations such as the desired tensile failure limit and wall thickness. The cross-sectional dimension of the one or more filaments 3042 extending in the axial direction, measured radially, may be about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 20%, 25%, or 30% or less of the cross-sectional dimension of the catheter 3000. The cross-sectional dimension of the one or more filaments 3042 extending in the axial direction, measured radially, may be about 0.001 inches, about 0.002 inches, about 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches, about 0.009 inches, about 0.010 inches, about 0.015 inches, about 0.020 inches, about 0.025 inches, or about 0.030 inches or less.

[0105] One or more filaments 3042 extending in the axial direction may increase the tensile strength of the distal zone of the catheter to at least about 1 pound, at least about 2 pounds, at least about 3 pounds, at least about 4 pounds, at least about 5 pounds, at least about 6 pounds, at least about 7 pounds, at least about 8 pounds, or at least about 10 pounds or more.

[0106] Any of the aspiration catheters or tubular extension segments disclosed herein may comprise a distal tip having an angled bevel, whether or not axial filaments are included. Referring to FIG. 7E, the distal catheter tip 3110 includes a tubular body 3112 that includes a forward section 3114, a marker band 3116, and a proximal section 3118. An inner tubular liner 3120 may extend over the entire length of the distal catheter tip 3110 and may include an immersion-coated PTFE.

[0107] A reinforcing element 3122, such as a braid or spring coil, is embedded within an outer jacket 3124, which may extend over the entire length of the distal catheter tip 3110.

[0108] The forward section 3114 terminates distally within a plane 3126 having an angled bevel, providing a leading sidewall portion 3128 having a length measured between the distal end 3130 of the marker band 3116 and the distal tip 3132. The trailing sidewall portion 3134 of the forward section 3114 has an axial length in the illustrated embodiment that is approximately equal to the axial length of the leading sidewall portion 3128, measured approximately 180 degrees around the catheter from the leading sidewall portion 3128. The leading sidewall portion 3128 may have an axial length within the range of about 0.1 mm to about 5 mm, and generally within the range of about 1 to about 3 mm. The trailing sidewall portion 3134 may have a length that is at least about 0.1 or about 0.5 or about 1 mm or about 2 mm or more shorter than the axial length of the leading sidewall portion 3128, depending on the desired performance.

[0109] The angled surface 3126 is inclined at an angle A within a range of from about 45 degrees to about 80 degrees from the longitudinal axis of the catheter. In certain implementations, this angle is within a range of from about 55 degrees to about 65 degrees, i.e., within a range of from about 55 degrees to about 65 degrees from the longitudinal axis of the catheter. In one implementation, the angle A is about 60 degrees. One result of the angle A being less than about 90 degrees is the elongation of the major axis of the area of the distal port, which increases the surface area of the port and may enhance the aspiration or retention of blood clots. Compared to the surface area of a circular port (where the angle A is 90 degrees), the area of the port with the angled surface is generally at least about 105% and up to about 130%, in some implementations within a range of from about 110% to about 125%, and in one example about 115%.

[0110] In the illustrated embodiment, the axial length of the advancement section is substantially constant around the circumference of the catheter such that the angled surface 3126 is approximately parallel to the distal surface 3136 of the marker band 3116. The marker band 3116 has a proximal surface that is approximately transverse to the longitudinal axis of the catheter, resulting in the marker band 3116 having a right trapezoidal configuration in a side elevation view. The short side wall 3138 is aligned in the rotational direction with the trailing side wall portion 3134 and has an axial length within a range of from about 0.2 mm to about 4 mm, and typically within a range of from about 0.5 mm to about 2 mm. The opposing long side wall 3140 is aligned in the rotational direction with the leading side wall portion 3128. The long side wall 3140 of the marker band 3116 is generally at least about 10% or 20% longer than the short side wall portion 3138 and may be at least about 50% or 70% or 90% or more longer than the short side wall portion 3138 depending on the desired performance. Generally, the long side wall 3140 will have a length of at least about 0.5 mm or 1 mm and less than about 5 mm or 4 mm.

[0111] The marker band may have at least one, and optionally two or three or more slits extending axially throughout its length to allow for radial expansion. The slits may be located on the short sidewall 3138, or on the long sidewall 3140, or between them, depending on the desired bending characteristics. The marker band may preferably comprise any of a variety of radiopaque materials having a wall thickness of about 0.003 inches or less, and in one implementation about 0.001 inches, such as a platinum / iridium alloy.

[0112] The marker band zone of the assembled catheter will have a relatively high bending stiffness and a high crush strength, for example at least about 50% or at least about 100% less than the proximal section 18, but generally no more than about 200% less than the proximal section 3118. A high crush strength may provide radial support to the adjacent advancing section 3114, particularly the leading sidewall portion 3128, which may facilitate the distal tip 3132 functioning as a non-traumatic buffer device during transluminal advancement and provide resistance to shrinkage under vacuum. The proximal section 3118 preferably has a lower bending stiffness than the marker band zone, and the advancing section 3114 preferably has an even lower bending stiffness and crush strength than the proximal section 3118.

[0113] The advancing section 3114 may include the outer jacket 3124 and optionally the distal extension of the inner liner 3120, distally from the marker band 3116 without any other internal support structure. The outer jacket may comprise extruded Tecothane. The advancing section 3114 may have corresponding values that are about 50% or less, and in some implementations about 25% or about 15% or about 5% or less, of the bending stiffness and radial crush stiffness for the proximal section 3118.

[0114] As described elsewhere herein, the support fiber 3142 extends through at least the distal portion of the length of the proximal segment 3118. As illustrated, the support fiber 3142 may terminate distally at the proximal surface of the marker band 3116 and may extend axially radially outward from the tubular liner 3120 and radially inward from the support coil 3122. The fiber 3142 may extend substantially parallel to the longitudinal axis or may be angled and loosened into a helix having 10 or 7 or 3 or 1 or fewer full revolutions around the catheter along the length of the helix. The fiber may comprise a high-tensile material such as a multifilament yarn spun from a liquid crystal polymer such as Vectran multifilament LCP fiber.

[0115] Depending on whether the catheter 3000 can be navigated sufficiently distally to reach the target site, a luminal extension catheter, such as a tubular extensible extension segment having a proximally extending control wire, may be inserted through the catheter 3000 from the proximal end of the catheter 3000. The extension segment is inserted and advanced distally such that the distal end of the extension segment reaches further distally beyond the distal end of the catheter 3000. The outer diameter of the extension segment is smaller than the inner diameter of the catheter 3000. In this way, the extension segment can slide within the lumen of the catheter 3000.

[0116] The extension segment incorporates the characteristics of the sidewall structure of the catheter 3000 described herein. The axial length of the tubular extension segment may be less than about 50% of the length of the catheter 3000 and typically may be less than about 25%. The axial length of the tubular extension segment generally is at least about 10 cm or 15 cm or 20 cm or 25 cm or more, but generally is about 70 cm or 50 cm or 30 cm or less.

[0117] Referring to FIGS. 8A - 8C, any of the catheters described herein may have one or more filaments 3242 extending axially.

[0118] Referring to FIGS. 10A - 10B, the beveled surface 3126 of the catheter of FIG. 7E is further modified to a surface 4000 with a blunted bevel such that the leading edge tip (shown in FIG. 7E) is removed. As shown in FIG. 10B, the catheter distal surface 4000 includes a first section 4012 that lies in a first plane crossing the longitudinal axis of the tubular body at a first angle 4020 within the range of about 35 degrees to about 55 degrees, and a second section 4014 that lies in a second plane crossing the longitudinal axis of the tubular body at a second angle 4010 within the range of about 55 degrees to about 90 degrees. The section 4016 of the distal surface 4000 shown in FIG. 7E is removed. One result of the angle 4020 being less than 90 degrees and the length 4014 being blunted is an elongation of the major axis of the area of the distal port, which increases the surface area of the port, enhancing the aspiration or retention of blood clots while potentially minimizing the likelihood of vascular wall damage.

[0119] Compared to the surface area of a circular port (both the angle 4020 and the angle 4010 are 90 degrees), the area of the blunted port with a bevel is generally at least about 105% and about 150% or less, and in some implementations within the range of about 110% to about 125%, and in one example, about 115%. The degree of blunting can be defined by the ratio of the non - blunted axial length 4022 measured from the trailing edge 4024 to the leading edge 4026 to the blunted axial length shown as section 4018.

[0120] As shown in FIG. 10A, a passivation ratio of 3 / 4 is shown. The length 4016 where the tip 4000 is passivated is in the range of 1 to 5 mm, 1 to 4 mm, 1 to 3 mm, 1 to 2 mm, 0.1 to 0.2 mm, 0.2 to 0.3 mm, 0.3 to 0.4 mm, 0.4 to 0.5 mm, 0.5 to 0.6 mm, 0.6 to 0.7 mm, 0.7 to 0.8 mm, 0.8 to 0.9 mm, 0.9 to 1.0 mm, 0.1 to 0.5 mm, 0.5 to 1.0 mm, less than 1 mm, greater than 1 mm, at least 2 mm, at least 3 mm, at least 4 mm, at least 5 mm, or any range or sub-range therebetween of the entire catheter distal surface 4022. In some embodiments, the length 4016 of the distal surface 4000 is defined by a percentage of the outer diameter of the catheter. For example, the length 4016 may be equal to a length in the range of 10% to 500%, 10% to 20%, 20% to 30%, 30% to 40%, 40% to 50%, 50% to 60%, 60% to 70%, 70% to 80%, 80% to 90%, 100% to 200%, 200% to 300%, 300% to 400%, 400% to 500%, or any range or sub-range therebetween of the outer diameter of the catheter.

[0121] Referring to FIG. 10B, the angle 4020 of the first or angled section of the distal surface 4000 may be 5 to 10 degrees, 10 to 15 degrees, 15 to 20 degrees, 20 to 25 degrees, 25 to 30 degrees, 30 to 35 degrees, 35 to 40 degrees, 40 to 45 degrees, 45 to 50 degrees, 50 to 55 degrees, 55 to 60 degrees, 60 to 65 degrees, 65 to 70 degrees, 70 to 75 degrees, 75 to 80 degrees, 80 to 85 degrees, 85 to 90 degrees, 90 to 95 degrees, or any range or sub-range therebetween. The angle 4020 of the first or angled section of the distal surface 4000 may be at least 10 degrees, at least 15 degrees, at least 20 degrees, at least 25 degrees, at least 30 degrees, at least 35 degrees, at least 40 degrees, at least 45 degrees, at least 50 degrees, at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, at least 90 degrees, or at least 95 degrees. In some embodiments, the angle 4020 of the first or angled section of the distal surface is equal to 0 to 30 degrees, 30 to 60 degrees, 60 to 90 degrees, or any range or sub-range therebetween. In some embodiments, the angle 4020 is equal to 15 to 45 degrees, 45 to 75 degrees, 75 to 95 degrees, or any range or sub-range therebetween. The angle 4010 of the second or blunted section of the distal surface 4000 may be 55 to 60 degrees, 60 to 65 degrees, 65 to 70 degrees, 70 to 75 degrees, 75 to 80 degrees, 80 to 85 degrees, 85 to 90 degrees, or any range or sub-range therebetween. The angle 4010 of the second or blunted section of the distal surface 4000 may be at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, or at least 90 degrees. In some embodiments, the angle 4010 of the second or blunted section of the distal surface 4000 is equal to 55 to 65 degrees, 65 to 75 degrees, 75 to 90 degrees, or any range or sub-range therebetween.

[0122] Referring to FIGS. 11A - 11B, a distal surface 4100 in the shape of a sine curve is shown, which includes a first section or convex wave or shape or shovel or curve 4110 defined by a first radius of curvature, which transitions to a second section or concave wave or shape or shovel or curve 4120 defined by a second radius of curvature. Each curve 4110, 4120 may have a diameter in the range of, for example, 0.02 inches to 0.05 inches, depending on the size of the catheter. Each curve 4110, 4120 is further defined by a radius of curvature 4112, 4114, respectively, as shown in FIG. 41B. In some embodiments, the first convex curve 4110 and the second concave curve 4120 each have the same or similar or substantially similar (+ / - 5%) radii of curvature 4112, 4114. In other embodiments, the first convex curve 4110 and the second concave curve 4120 each have different radii of curvature 4112, 4114. The 2D profile of the distal surface shape 4100 (e.g., when projected onto the radial plane shown in FIG. 11A) is given by the following equation:

Equation

[0123] As shown in FIG. 11A, the slopes or angles of each curve 4110, 4120 can be defined by angles 4140 and 4150, respectively. For example, to calculate each of angles 4140, 4150, an axis can be positioned at the transition point along the longitudinal center of the catheter between the first curve 4110 and the second curve 4120 such that angles 4140, 4150 define the curve or shape of the distal face 4100. In some embodiments, angle 4140 is from 0 to 5 degrees, 5 to 10 degrees, 10 to 15 degrees, 15 to 20 degrees, 20 to 25 degrees, 25 to 30 degrees, 30 to 35 degrees, 35 to 40 degrees, 40 to 45 degrees, 45 to 50 degrees, 50 to 55 degrees, 55 to 60 degrees, 60 to 65 degrees, 65 to 70 degrees, 70 to 75 degrees, 75 to 80 degrees, 80 to 85 degrees, 85 to 90 degrees, or any range or sub-range therebetween. In some embodiments, angle 4140 is from 30 to 60 degrees, 15 to 85 degrees, or any range or sub-range therebetween. In some embodiments, angle 4150 is from 0 to 5 degrees, 5 to 10 degrees, 10 to 15 degrees, 15 to 20 degrees, 20 to 25 degrees, 25 to 30 degrees, 30 to 35 degrees, 35 to 40 degrees, 40 to 45 degrees, 45 to 50 degrees, 50 to 55 degrees, 55 to 60 degrees, 60 to 65 degrees, 65 to 70 degrees, 70 to 75 degrees, 75 to 80 degrees, 80 to 85 degrees, 85 to 90 degrees, or any range or sub-range therebetween. In some embodiments, angle 4150 is from 30 to 60 degrees, 15 to 85 degrees, or any range or sub-range therebetween.

[0124] Referring to FIG. 12, a schematic diagram of a numerical simulation model is shown. A computational fluid dynamics (CFD) model was created to simulate suction of a soft blood clot 4120 within a blood vessel 4210, surrounded by blood 4130, into a catheter 4140 having various shapes or angles 4150 of the distal face.

[0125] Exemplary CFD model data are shown in FIGS. 13A - 13B. Images of the numerical simulation of blood clot aspiration show the initial state 4300 in FIG. 13A and the effective aspiration state 4310 in FIG. 13B. The amount of blood clot material aspirated over a predetermined time was measured for various shapes or angles 4150 of the distal surface. Values for a circular (transverse) port (e.g., as shown in FIG. 3A) were used as a baseline or control for benchmarking the good performance of the proposed profile. A particular shape or angle of the distal surface was considered to have better results to the extent that it could aspirate more material than the circular port shape. A higher aspiration rate indicates less resistance to aspiration and a lower likelihood of complications during aspiration - thrombectomy.

[0126] Referring to FIG. 14, the percent increase in aspirated volume is shown as a function of the distal surface angle. For example, for a distal surface showing an angle of 60 degrees, there was a maximum increase in aspiration efficiency compared to surfaces having smaller angles (from 15 degrees to 45 degrees). The aspirated volume for a surface with a 60 - degree bevel angle increased by more than 60% above circular, between 60 - 70% above the circular surface, or between 50 - 70% above the circular surface. For a distal surface with a 45 - degree bevel angle, there was an increase in aspirated volume of more than 40% above the circular surface, between 40 - 50%, between 30 - 60%, or more than 45%. For a distal surface with a 30 - degree bevel angle, there was an increase in aspirated volume of more than 20% above the circular surface, more than 25%, between 20 - 30%, or between 15 - 40%. Even for a distal surface with an angle of 15 degrees, an improvement in aspirated volume of 10% above the circular surface was shown.

[0127] Exemplary reasons for this improvement in suction efficiency as a function of the tip angle are: (1) an increase in the surface area of the catheter opening that contacts the blood clot, which increases the force exerted on the blood clot (pressure = force / area), and (2) an increase in its length that captures the thrombus over a certain distance (i.e., the capture length), which smooths the shape change as the blood clot flows from a larger-diameter blood vessel into a smaller-diameter catheter. The latter of these two design theories is supported by an investigation of the flow profile during the suction experiment. For a more distinct sinusoidal profile, the flow was more uniform and less turbulent when flowing into a smaller-diameter catheter. As shown in FIG. 14, as the angle of the face increases, the percent increase in suction volume increases, and overall, it is shown that the greater the face opening as a result of the face profile having an oblique angle, the greater the suction efficiency.

[0128] Turning to FIGS. 15A - 15C, these show the CFD velocity field profiles for cases of various face angles (i.e., no angle, i.e., 0 degrees, a 30-degree angle, and a 60-degree angle). As shown in FIG. 15A, the circular face profile shows a significant constriction of the flow, thus increasing the resistance to blood clot capture. In contrast, the distal faces having a 30-degree (FIG. 15B) or 60-degree (FIG. 15C) angle dramatically increased blood clot capture, as shown in each respective plot. As shown in FIG. 15C, the face having a 60-degree oblique angle shows that the distance between adjacent contour lines is even greater compared to the leading edge 4510 of the face having a 30-degree oblique angle, and that the leading edge 4500 of the velocity coefficient extends further into the modeled catheter body.

[0129] Turn to FIGS. 16A - 16B. FIG. 16A shows the capture length 4610 for the case of a surface 4600 with an oblique angle, and FIG. 16B shows the capture length 4620 for the case of a surface 4650 with a blunted oblique angle. In some embodiments, the length 4610 is equal to or substantially equal to the length 4620, and in other embodiments, the length 4610 is greater than, less than, or different from the length 4620. The capture length 4610 is determined by calculating the difference between the leading tip 4614 and the trailing tip 4612, and the leading edge and the trailing edge have been described in connection with FIG. 7E. Similarly, the capture length 4620 is determined by calculating the difference between the leading edge tip 4624 and the trailing edge tip 4622. In exemplary and non - limiting embodiments, the capture length ranges from 0.25 mm to 4.5 mm; 0.5 mm to 4 mm, 0.5 mm to 2.5 mm, 3.5 mm to 4 mm, 2 mm to 2.5 mm, 1.5 mm to 2 mm, 1 mm to 1.5 mm, 0.5 mm to 1 mm, etc. The capture length is directly related to the percent increase in the aspirated volume over that of a circular surface.

[0130] FIG. 17 illustrates the percent increase in the aspirated material for catheters having various distal surface profiles (i.e., those with an oblique angle, a blunted oblique angle, a sinusoidal shape) as a function of the capture length. All of the proposed profiles showed an improvement over the circular surface profile. That improvement ranged from substantially 10% to substantially 70%. In addition, the surfaces with a blunted oblique angle and the sinusoidal surfaces showed just as good results as the surfaces with an oblique angle having the same capture length. This suggests that blunted or smooth catheters can perform just as well as sharp catheters as long as the capture lengths are the same, similar, or substantially similar.

[0131] For example, when the capture length of the angled surface is in the range of about 0.5 mm to about 4 mm, the percent increase in suction volume above the circular surface control increased from about 10% to about 70%. When the capture length of the blunted surface with an angle is about 1 mm to about 1.6 mm, or about 1 mm to about 1.75 mm, the percent increase in suction volume above the circular surface control increased from about 18% to about 38%. The sinusoidal surface demonstrated an increase in suction volume of about 35% above the circular surface control for a capture length of about 1.7 mm to about 1.7 mm.

[0132] Referring to FIGS. 18A - 18B, an example of a multilayer pattern for the outer jacket section is illustrated for a progressive flexibility catheter of the type discussed, for example, in connection with FIGS. 1A or 7A. The distal section 3038 may have a length within the range of about 1 - 3 cm and a durometer of less than about 35D or 30D. The adjacent proximal section 3036 may have a length within the range of about 4 - 6 cm and a durometer of less than about 35D or 30D. The adjacent proximal section 3034 may have a length within the range of about 4 - 6 cm and a durometer of 35D or less. The adjacent proximal section 3032 may have a length within the range of about 1 - 3 cm and a durometer within the range of about 35D to about 45D (e.g., 40D). The adjacent proximal section 3030 may have a length within the range of about 1 - 3 cm and a durometer within the range of about 50D to about 60D (e.g., about 55D). The adjacent proximal section 3028 may have a length within the range of about 1 - 3 cm and a durometer within the range of about 35D to, about 50D to about 60D (e.g., about 55D). The adjacent proximal section 3026 may have a length within the range of about 1 - 3 cm and a durometer of at least about 60D, typically less than about 75D.

[0133] The more proximal segments may have a durometer of at least about 65D or 70D. The two or three most distal segments may include a material such as Tecothane, and the more proximal segments may include PEBAX, or other catheter jacket materials known in the art. At least three or five or seven or nine or more individual segments may be utilized, where the change in durometer between the highest and lowest along the length of the catheter shaft is at least about 10D, preferably at least about 20D, and in some implementations at least about 30D or 40D or more.

[0134] Performance metrics of the catheter include backup support, trackability, pushability, kink resistance, etc. Backup support means the ability to provide a stable platform where the catheter stays in an anatomically correct position and the endovascular device can advance through it. Referring to FIG. 19, when the device is pushed through the catheter 3202, without sufficient backup support within the catheter 3202, the distal portion 3204 of the catheter 3202 may exit, be pulled out of, or retract from the blood vessel 3206 branching from the main blood vessel (e.g., brachiocephalic artery 82, common carotid artery 80, or subclavian artery 84). The backup support of the catheter 3202 may be improved by providing a proximal region with a high durometer or modulus of elasticity and a distal region with a low durometer or modulus of elasticity.

[0135] The durometer or modulus of elasticity of the proximal region of the catheter 3202 may be improved by braided reinforcement. The region of the catheter where the durometer or modulus of elasticity is enhanced may cause a risk of the catheter with poor backup support to escape, and the aortic arches 1114, 1214, where the brachiocephalic artery 82, common carotid artery 80, or subclavian artery 84 branches, are near the bifurcation point, or near other anatomical structures (i.e., bifurcation points) where the main blood vessel branches into one or more smaller blood vessels. For example, the region of the catheter with enhanced durometer or modulus of elasticity may be arranged within a range of about 0.5 cm, about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, or about 6 cm from the bifurcation point where the main blood vessel branches into one or more smaller blood vessels.

[0136] Trackability means the ability of a catheter to track further distally (e.g., up to M1) than other catheters. For example, a catheter that can reach the cerebral segment of the internal carotid artery (ICA) has better trackability than a catheter that can reach the cavernous or pyramidal segment of the ICA. The trackability of a catheter may be improved by using a catheter wall with a low durometer or modulus of elasticity, or by applying a coating (e.g., a hydrophilic coating) to at least a portion of the catheter wall. In one embodiment, the hydrophilic coating may be arranged along the most distal region of the catheter. The hydrophilic coating on the catheter may extend from about 1 cm, about 5 cm, about 10 cm, about 15 cm, or about 20 cm from the distal end of the catheter. The region with a lower durometer or modulus of elasticity may be located in the most distal region of the catheter. The region with a lower durometer or modulus of elasticity may extend from about 1 cm, about 5 cm, about 10 cm, about 15 cm, or about 20 cm from the distal end of the catheter.

[0137] Pushability means the catheter has sufficient rigidity to be pushed through the anatomical structure without "buckling". The pushability of a catheter may be improved by increasing its durometer or modulus of elasticity. Also, the pushability of a catheter may be improved by providing a proximal region having a high durometer or modulus of elasticity and a distal region having a low durometer or modulus of elasticity. The transition region of a catheter with a durometer or modulus of elasticity varied along its longitudinal length (e.g., a decrease in durometer or modulus of elasticity from the proximal end to the distal end) may begin at about 50%, 60%, 70%, 75%, 80%, or more of the catheter length from its proximal end.

[0138] Kink resistance means that the catheter is resistant to kinking. Additionally, when the catheter does actually kink, the kink resistance of the catheter helps the catheter return to its original shape. Kink resistance is important in the distal portion of the catheter, which is more prone to kinking than the proximal portion. The kink resistance of a catheter may be improved by adding one or more NiTi coils (or coils at least partially made of nitinol) to the catheter wall.

[0139] Figure 20 depicts a graph of the durometer or modulus of elasticity of a catheter according to the present invention along the length of the catheter from the proximal end (x = 0) to the distal end (x = 1). A catheter according to one embodiment may have a durometer or modulus of elasticity (E) that decreases as it approaches its distal end. The proximal end of the catheter has a higher durometer or modulus of elasticity than the distal end of the catheter. A higher durometer or modulus of elasticity near the proximal end provides better backup support for the catheter. The durometer or modulus of elasticity of the catheter is substantially constant along its length near the proximal end 3302 of the catheter. Then, the durometer or modulus of elasticity of the catheter decreases near the distal end 3304 of the catheter. The durometer or modulus of elasticity of the catheter may begin to decrease at about 50%, 70%, 75%, 80%, or 90% of the length of the catheter from its proximal end (i.e., the transition region). The catheter may have a durometer or modulus of elasticity that sequentially decreases near its distal end by using a material having a decreasing durometer or modulus of elasticity near the distal end or by having a catheter wall that thins there. The decreased durometer or modulus of elasticity near the distal end provides excellent followability of the catheter.

[0140] Figure 21 depicts the flexibility test profile of a catheter according to the present invention compared to a conventional catheter. The flexibility of the catheter was measured by a three-point bend test using a 1-inch span and a 2-mm displacement. In other words, Figure 21 depicts the force (i.e., the bending load) required to displace a 1-inch length of the catheter section 2 mm in the vertical direction with respect to the distance from the stress relief (i.e., the proximal end of the catheter) to the point of force application. The modulus of elasticity of the catheter remains substantially constant along its length near the proximal end and then gradually decreases near the distal end.

[0141] The catheter according to the present invention has a bending load that is substantially constant along the longitudinal length near the proximal end and rapidly decreases near the distal end. For a catheter having a length of about 125 cm, the catheter may have a bending load of about 1.0 lbF, about 1.5 lbF, about 2.0 lbF, about 2.5 lbF, about 3.0 lbF, or about 3.5 lbF or more at about 85 cm from the proximal end. The catheter may have a bending load of about 2.5 lbF, about 2.0 lbF, about 1.5 lbF, about 1.0 lbF, or about 0.5 lbF or less at about 95 cm from the proximal end. The catheter may have a bending load of about 1.5 lbF, about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.25 lbF, or about 0.1 lbF or less at about 105 cm from the proximal end. The catheter may have a bending load of about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.4 lbF, about 0.3 lbF, about 0.2 lbF, or about 0.1 lbF or less at about 115 cm from the proximal end. For catheters having different lengths, the dimensions can be scaled as a percentage of the catheter length from the distal end of the catheter.

[0142] In a particular implementation constructed in accordance with FIG. 5, the bending load is less than about 3.0 or 3.25 lbF at 65 cm from the proximal end and averages greater than about 2.25 or 2.5 lbF from 65 cm to 85 cm from the proximal end. The bending load drops to about 1.0 or less, preferably about 0.5 lbF or less, at about 95 cm from the proximal end. This provides enhanced backup support in the aorta while maintaining enhanced tracking in the distal vasculature.

[0143] In other embodiments, the catheter may have a bending load of about 1.0 lbF, about 1.5 lbF, about 2.0 lbF, about 2.5 lbF, about 3.0 lbF, or about 3.5 lbF or more at about 60 cm from the proximal end. The catheter may have a bending load of about 2.0 lbF, about 1.5 lbF, about 1.0 lbF, or about 0.5 lbF or less at about 70 cm from the proximal end. The catheter may have a bending load of about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.4 lbF, about 0.3 lbF, about 0.2 lbF, or about 0.1 lbF or less at about 80 cm from the proximal end. The catheter may have a bending load of about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.4 lbF, about 0.3 lbF, about 0.2 lbF, or about 0.1 lbF or less at about 90 cm from the proximal end.

[0144] The catheter may have a transition region with a bending load varying by about 1.0 lbF, about 1.5 lbF, about 2.0 lbF, about 2.5 lbF, about 3.0 lbF, or about 3.5 lbF or more. The longitudinal length of the transition region may be about 20 cm, about 15 cm, about 10 cm, about 5 cm, about 3 cm, or about 1 cm or less.

[0145] Compared to the Neuron Max (Penumbra, Inc.) 3402, the catheters according to the present invention (e.g., 3404, 3406, 3408, 3410) have a similar modulus of elasticity near their proximal ends. In this way, the catheters according to the present invention provide backup support equivalent to that of the Neuron Max. Additionally, these catheters have a modulus of elasticity that decreases more rapidly than that of the Neuron Max near the transition region (between the proximal and distal ends).

[0146] Compared with the Ace 68 catheter (penumbra) 3412, Ace 64 catheter (penumbra) 3414, Benchmark 71 catheter (penumbra) 3416, and Sofia Plus (MicroVention) 3418, the catheter according to the present invention has a greater modulus of elasticity near its proximal end and a comparable modulus of elasticity near its distal end. In this way, the catheter according to the present invention may provide better backup support with comparable tracking ability compared to conventional catheters. The catheters according to the present invention may achieve this modulus of elasticity profile even when their inner diameters (and thus lumen volumes) are greater than the inner diameters in the range of 0.064 inches to 0.071 inches of Ace 68, Ace 64, Benchmark 71, and Sofia Plus.

[0147] Access suitable for the catheter of the present invention can be achieved using conventional techniques through incisions in peripheral arteries such as the right femoral artery, left femoral artery, right radial artery, left radial artery, right brachial artery, left brachial artery, right axillary artery, left axillary artery, right subclavian artery, or left subclavian artery. In an emergency, the right or left carotid artery can also be incised.

[0148] By preventing the guide wire and the inner diameter of the guide wire lumen from fitting too tightly, the slidability of the catheter over the guide wire is enhanced. In a super-small diameter catheter design, it may be desirable to coat the outer surface of the guide wire and / or the inner surface of the wall defining the GW lumen with a lubricious coating to minimize the friction when axially moving the catheter 10 relative to the guide wire. Various coatings such as Paralene, Teflon, silicone, polyimide-polytetrafluoroethylene composite materials, or other suitable ones known in the art depending on the guide wire or the inner tubular wall may be utilized.

[0149] The aspiration catheter of the present invention adapted for intracranial application generally has an overall length in the range of 60 cm to 250 cm, typically in the range of about 135 cm to about 175 cm. The length of the proximal section 33 is typically from 20 cm to 220 cm, more typically from 100 cm to 120 cm. The length of the distal section 34 is typically in the range of 10 cm to about 60 cm, usually about 25 cm to about 40 cm.

[0150] The catheter of the present invention may comprise any of a variety of biocompatible polymeric resins having suitable properties when formed in the tubular catheter body section. Exemplary materials include polyvinyl chloride, polyethers, polyamides, polyethylene, polyurethanes, their copolymers, and the like. Optionally, the catheter body may be reinforced with a metallic or polymeric braid, or other conventional reinforcing layer.

[0151] The catheter body may further comprise other components, such as radiopaque fillers; colorants; reinforcing materials; reinforcing layers, such as braids or helical reinforcing elements; and the like. In particular, the proximal body section may be reinforced to increase its column strength and torqueability (torque transmissibility) while preferably limiting its wall thickness and outer diameter.

[0152] In one aspect of the present disclosure, a system for aspirating a vascular occlusion further comprises a controller that applies a pulsatile vacuum cycle to the central lumen. In another aspect of the present disclosure, a system for aspirating a vascular occlusion further comprises a rotary hemostatic valve coupled to the proximal end of the tubular body, the rotary hemostatic valve comprising: at least one main lumen along its longitudinal length, the main lumen being configured such that the proximal portion of the thrombus grasping device passes therethrough, and a suction lumen branched from the main lumen and provided with a vacuum port.

[0153] In accordance with another aspect: advancing a guide wire from a femoral access site to a site at least as distal as the cerebral segment of the internal carotid artery, the guide wire having a proximal section with a diameter of at least about 0.030 inches and a distal section with a length of about 25 cm or less and a diameter of about 0.020 inches or less; and advancing a suction catheter directly over the guide wire and at least as distal as at least the cavernous segment, the suction catheter having a distal end and a central lumen at the distal end with a diameter of at least about 0.080 inches and an angled distal tip. A method of aspirating material from at least as distal as the cavernous segment of the internal carotid artery through a femoral access site is provided. In one aspect of the disclosure, the proximal section of the guide wire has a diameter of about 0.038 inches and the distal section has a diameter of about 0.016 inches.

[0154] With the distal end positioned at least as distal as the cavernous segment of the middle cerebral artery, a vacuum is applied to the lumen to draw the thrombus into the lumen; the thrombus is mechanically engaged to facilitate attachment to and potentially entry into the lumen.

[0155] The step of mechanically engaging may include advancing a thrombus grasping device to or beyond the distal end of the tubular body. The method of engaging a vascular occlusion may include manually rotating a thrombus grasping device within the tubular body to engage the thrombus.

[0156] In yet another aspect of the present disclosure, a method of aspirating a vascular occlusive substance further includes providing sufficient backup support to an access and aspiration combination catheter to resist withdrawal of the catheter from the aorta. To provide backup support to the access and aspiration combination catheter, a guide wire having a distal end positioned at least as distal as the cavernous segment of the internal carotid artery and having a diameter at least about 0.030 inches at the point where it enters the brachiocephalic artery may be advanced over the access and aspiration combination catheter. To provide backup support to the access and aspiration combination catheter, a guide wire having a distal end positioned at least as distal as the cavernous segment of the internal carotid artery and having a diameter at least about 0.030 inches, such as about 0.035 inches, or 0.038 inches at the point where it enters the brachiocephalic artery is advanced over the access and aspiration combination catheter.

[0157] The guide wire is navigable at least through the cerebral segment of the internal carotid artery by having a distal segment with a diameter of about 0.020 inches or less. The guide wire may be navigable through at least the cerebral segment of the internal carotid artery by having a distal segment with a diameter of about 0.016 inches. The diameter of the proximal section of the guide wire may be about 0.038 inches and the diameter of the distal section may be about 0.016 inches.

[0158] Although the invention has been described in terms of preferred embodiments, other embodiments may be incorporated by those skilled in the art in light of the disclosure herein. Accordingly, the scope of the invention is not intended to be limited by the specific embodiments disclosed herein, but is intended to be defined by the broadest scope of the following claims.

Example

[0159] A system for removing embolic material from an intravascular location,

[0160] An elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

[0161] An axial restraint device carried by the sidewall and exposed to the lumen;

[0162] A rotatable core wire extending axially through the lumen and having a proximal end and a distal end;

[0163] A limiting device carried by the core wire and having a bearing surface rotatably engaged with the restraint device;

[0164] One or more of a thrombus gripping tip at the distal end of the core wire;

[0165] A system in which the limiting device and the restraint device are configured to allow rotation of the core wire but limit distal advancement of the tip to about 6 mm or less beyond the distal end of the tubular body.

[0166] A system for removing an embolizing substance from an intravascular site, as disclosed in any of the embodiments herein, wherein the limiting device and the restraint device are configured to allow rotation of the core wire but limit distal advancement of the tip to about 3 mm or less beyond the distal end of the tubular body.

[0167] A system for removing an embolizing substance from an intravascular site, as disclosed in any of the embodiments herein, wherein the thrombus gripping tip includes a helical thread configuration.

[0168] A system for removing an embolizing substance from an intravascular site, as disclosed in any of the embodiments herein, wherein the limiting device and the restraint device are configured to allow rotation of the core wire but limit distal advancement of the tip to exposure between about 1 and 3 full rotations of the thread structure beyond the distal end of the tubular body.

[0169] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the axial restraint device includes a bearing surface facing proximally.

[0170] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the axial restraint device includes a protrusion extending radially inwardly.

[0171] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the axial restraint device includes an annular flange.

[0172] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the limiting device includes a bearing surface facing distally.

[0173] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the limiting device includes a protrusion extending radially outwardly.

[0174] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the protrusion extending radially outwardly is configured to slidably contact the restraint device.

[0175] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the proximal bearing surface on the axial restraint device is within a range of about 30 cm from the distal end of the tubular body.

[0176] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the proximal bearing surface is within a range of about 4 cm to 12 cm from the distal end of the tubular body.

[0177] A system for removing embolic material from an intravascular site, as disclosed in any of the embodiments herein, wherein the helical thread shape has a maximum outer diameter that is about 90% or less of the inner diameter of the lumen, leaving an annular flow path between the tip and the inner surface of the side wall.

[0178] A system for removing an embolic substance from an intravascular location, wherein the helical thread shape has a blunted outer edge, as disclosed in any of the embodiments of the present specification.

[0179] A system for removing an embolic substance from an intravascular location, wherein the restraining device is positioned within a range of approximately the distal 25% of the core wire length, as disclosed in any of the embodiments of the present specification.

[0180] A system for removing an embolic substance from an intravascular location, wherein the core wire is removably positionable within the tubular body, as disclosed in any of the embodiments of the present specification.

[0181] A system for removing an embolic substance from an intravascular location, further comprising a handle configured to manually rotate the core wire, as disclosed in any of the embodiments of the present specification.

[0182] A system for removing an embolic substance from an intravascular location, wherein the helical thread shape extends through a rotation of no more than about 8 full rotations, as disclosed in any of the embodiments of the present specification.

[0183] A system for removing an embolic substance from an intravascular location, wherein the helical thread shape has an outer diameter that increases from a first diameter near the distal tip to a second maximum outer diameter in the proximal direction and then decreases from the maximum outer diameter to a third diameter in the proximal direction, as disclosed in any of the embodiments of the present specification.

[0184] A system for removing an embolic substance from an intravascular location, wherein the inner diameter of the tubular body adjacent to the thrombus gripping tip is at least about 0.015 inches greater than the maximum outer diameter of the tip, as disclosed in any of the embodiments of the present specification.

[0185] A torque transmission system for rotationally orienting the distal end of a catheter,

[0186] An elongate flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

[0187] A first engagement surface carried by the sidewall and exposed to the lumen;

[0188] A torque wire extendable and retractable through the lumen and having a proximal end and a distal end;

[0189] Including one or more of a second engagement surface carried by the torque wire; such that,

[0190] Upon distal advancement of the torque wire, the second engagement surface is in a state of coupling engagement with the first engagement surface by rotation, such that rotation of the distal end of the catheter is caused by rotation of the torque wire in at least a first direction. A system made in this way.

[0191] The torque transmission system disclosed in any embodiment of this specification, wherein the first engagement surface includes at least one inclined surface.

[0192] The torque transmission system disclosed in any embodiment of this specification, wherein the first engagement surface is carried by a protrusion extending radially inward.

[0193] The torque transmission system disclosed in any embodiment of this specification, wherein the protrusion includes a ring positioned within the lumen.

[0194] The torque transmission system disclosed in any embodiment of this specification, wherein the second engagement surface includes a surface facing distally.

[0195] The torque transmission system disclosed in any embodiment of this specification, wherein the surface facing distally includes at least one inclined surface.

[0196] A torque transmission system for rotationally orienting a distal end of a catheter,

[0197] a tubular body that is an elongated flexible tubular member having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

[0198] a first connector on the sidewall and exposed to the lumen;

[0199] a torque wire that is axially extensible through the lumen and has a proximal end and a distal end;

[0200] including one or more of a second, complementary connector carried by the torque wire;

[0201] a system in which rotation of the distal end of the catheter is enabled in response to rotation of the torque wire by coupling of the first and second connectors.

[0202] The torque transmission system disclosed in any embodiment of this specification, wherein the first connector includes at least one toothed portion having an oblique angle.

[0203] The torque transmission system disclosed in any embodiment of this specification, wherein the first connector includes a protrusion extending radially inward.

[0204] The torque transmission system disclosed in any embodiment of this specification, wherein the protrusion includes a ring positioned within the lumen.

[0205] The torque transmission system disclosed in any embodiment of this specification, wherein the ring includes at least two toothed portions having an oblique angle and extending in the proximal direction.

[0206] The torque transmission system disclosed in any embodiment of this specification, wherein the second connector includes a surface facing distally and carried by the torque wire.

[0207] A torque transmission system according to any embodiment disclosed herein, wherein the surface facing distally includes at least one inclined surface.

[0208] A torque transmission system according to any embodiment disclosed herein, wherein the second connector is movable radially outward.

[0209] A torque transmission system according to any embodiment disclosed herein, wherein the second connector includes an inflatable balloon and the first connector includes a surface on the sidewall.

[0210] A torque transmission system according to any embodiment disclosed herein, wherein the first connector includes sidewalls of an axially extending elongated groove configured to receive a protrusion on the torque wire.

[0211] A method of rotationally orienting a catheter, comprising:

[0212] advancing a catheter having a central lumen and a distal end to a site within a body cavity;

[0213] advancing a torque wire into the lumen;

[0214] engaging a first connector of the torque wire with a second connector on the catheter;

[0215] rotating the torque wire to effect rotation of the distal end of the catheter, the method including one or more of the foregoing steps.

[0216] A system for removing an embolic substance from an intravascular site, comprising:

[0217] an elongated flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

[0218] A first engagement surface carried by the side wall and exposed to the lumen;

[0219] A rotatable tap wire that is telescopically extendable through the lumen and has a proximal end and a distal end;

[0220] A second engagement surface carried by the tap wire, and includes,

[0221] A system in which, upon distal advancement of the tap wire, the second engagement surface contacts the first engagement surface and momentum is transferred from the tap wire to the distal end of the tubular body.

[0222] A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the first engagement surface includes a surface facing proximally.

[0223] A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the first engagement surface is carried by a protrusion extending radially inward.

[0224] A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the first engagement surface includes an annular flange.

[0225] A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the second engagement surface includes a surface facing distally.

[0226] A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the surface facing distally is the distal end of the tap wire.

[0227] A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the surface facing distally is on a hammer head carried by the wire.

[0228] A system for facilitating distal advancement of a catheter, comprising:

[0229] An elongated flexible tubular body having a proximal end, a distal end, and a lumen extending therethrough;

[0230] A distal restraint device within the lumen;

[0231] A guidewire positionable axially movably through the lumen and having a distal stopper thereon; and including one or more of:

[0232] A system in which distal movement of the distal stopper through the lumen is restricted by the distal restraint device.

[0233] A system for facilitating distal advancement of a catheter, as disclosed in any embodiment herein, wherein the distal restraint device includes a ring.

[0234] A system for facilitating distal advancement of a catheter, as disclosed in any embodiment herein, wherein the tubular body terminates within an inclined plane.

[0235] A neurovascular catheter having a tip for non-invasive navigation, comprising:

[0236] An elongated flexible tubular body having a proximal end, a distal end, and a sidewall defining a central lumen; and including any one of:

[0237] The distal zone of the tubular body being:

[0238] A tubular inner liner;

[0239] A helical coil surrounding the inner liner and having a distal end;

[0240] A tubular jacket surrounding the helical coil and extending distally beyond the distal end of the helical coil to terminate at a catheter distal face;

[0241] A tubular radiopaque marker embedded within the tubular jacket between the distal end of the coil and the distal surface,

[0242] The catheter distal surface includes a first section that resides on a first plane that intersects the longitudinal axis of the tubular body at a first angle within a range of about 35 degrees to about 55 degrees, and a second section that resides on a second plane that intersects the longitudinal axis of the tubular body at a second angle within a range of about 55 degrees to about 90 degrees. A catheter.

[0243] The marker has a proximal surface that is approximately perpendicular to the longitudinal axis and a marker distal surface that resides on a plane that intersects the longitudinal axis at an angle within a range of about 55 degrees to about 65 degrees. A neurovascular catheter having a tip for non-invasive navigation, disclosed in any of the embodiments herein.

[0244] The distal surface defines a leading edge of the tubular body that extends distally from a trailing edge of the tubular body, and the leading edge and the trailing edge are spaced apart from each other by about 180 degrees around the longitudinal axis. A neurovascular catheter having a tip for non-invasive navigation, disclosed in any of the embodiments herein.

[0245] The advancing section of the tubular body extends distally beyond the marker band. A neurovascular catheter having a tip for non-invasive navigation, disclosed in any of the embodiments herein.

[0246] The advancing section has an axial length within a range of about 0.1 mm to about 5 mm on the leading edge of the tubular body. A neurovascular catheter having a tip for non-invasive navigation, disclosed in any of the embodiments herein.

[0247] The axial length of the advancing section on the leading edge of the tubular body is greater than the length of the advancing section on the trailing edge of the tubular body. A neurovascular catheter having a tip for non-invasive navigation, disclosed in any of the embodiments herein.

[0248] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the axial length of the marker band on the leading edge of the tubular body is at least about 20% longer than the axial length of the marker band on the trailing edge of the tubular body.

[0249] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the axial length of the marker band on the leading edge of the tubular body is in the range of about 1 mm to about 5 mm.

[0250] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the marker band includes at least one axial slit.

[0251] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the tubular liner is formed by dip-coating a removable mandrel.

[0252] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the tubular liner includes PTFE.

[0253] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, further comprising a binding layer between the inner liner and the helical coil.

[0254] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the binding layer has a wall thickness of about 0.005 inches or less.

[0255] A neurovascular catheter having a tip for non-invasive navigation, as disclosed in any embodiment herein, wherein the binding layer extends along at least 20 cm of the most distal portion of the flexible body.

[0256] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the coil contains nitinol.

[0257] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the nitinol contains an austenitic state at body temperature.

[0258] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the outer jacket is formed from at least five individual tubular segments adjacent in the axial direction.

[0259] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the outer jacket is formed from at least nine individual tubular segments adjacent in the axial direction.

[0260] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the durometer difference between the proximal one of the tubular segments and the distal one of the tubular segments is at least about 20D.

[0261] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the durometer difference between the proximal one of the tubular segments and the distal one of the tubular segments is at least about 30D.

[0262] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, further comprising a tension support for increasing the tension resistance of the distal zone.

[0263] A neurovascular catheter having a distal end for non-invasive navigation, as disclosed in any embodiment herein, wherein the tension support includes axially extending filaments.

[0264] A neurovascular catheter having a non-invasive navigation tip disclosed in any embodiment herein, wherein the filament extending in the axial direction is carried between the inner liner and the helical coil.

[0265] A neurovascular catheter having a non-invasive navigation tip disclosed in any embodiment herein, wherein the filament extending in the axial direction increases the tensile strength of the tubular body by at least about 2 pounds.

Claims

1. A system for removing an embolic substance from within a blood vessel, comprising: a tubular body that is an elongated flexible tube having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough; an axial restraint device including a bearing surface facing proximally; a rotatable core wire that is telescopically extendable through the lumen and has a proximal end and a distal end; a limiting device carried by the core wire and having a bearing surface facing distally configured to abut against the bearing surface facing proximally of the restraint device; an engagement tip at the distal end of the core wire, the engagement tip including a helical thread shape; and wherein the limiting device and the restraint device are configured to allow rotation of the core wire, and wherein the limiting device and the restraint device are configured such that when the distal end of the core wire is approximately aligned with the distal end of the tubular body, the bearing surface facing distally of the limiting device and the bearing surface facing proximally of the restraint device are separated by an axial gap.

2. The system of claim 1, wherein the limiting device and the restraint device are configured to allow rotation of the core wire but limit distal advancement of the engagement tip to about 3 mm or less beyond the distal end of the tubular body.

3. The system of claim 1, wherein the limiting device and the restraint device are configured to allow rotation of the core wire but limit distal advancement of the engagement tip to exposure during about 1 to 3 full rotations of the thread shape beyond the distal end of the tubular body.

4. The system of claim 1, wherein the helical thread shape has a maximum outer diameter of about 90% or less of the inner diameter of the lumen, leaving an annular flow path between the engagement tip and the inner surface of the sidewall.

5. The system of claim 1, wherein the helical thread shape has a blunted outer edge.

6. The system of claim 1, wherein the core wire is removably positionable within the tubular body.

7. The system of claim 1, further comprising a handle configured to manually rotate the core wire.

8. The system of claim 1, wherein the helical thread shape extends through a rotation of about 8 full rotations or less.

9. The system according to claim 1, wherein the helical thread shape has an outer diameter that increases from a first diameter near the distal tip to a second maximum outer diameter in the proximal direction and then decreases from the maximum outer diameter to a third diameter in the proximal direction.

10. The system according to claim 1, wherein the inner diameter of the tubular body adjacent to the engaging tip is at least about 0.015 inches larger than the maximum outer diameter of the engaging tip.

11. The system according to claim 1, further comprising a tubular radiopaque marker embedded in the flexible tubular body.

12. The system according to claim 1, wherein the distal end of the tubular body comprises an inclined surface.

13. The system according to claim 1, wherein at least a portion of the engaging tip is located outside the tubular body when the bearing surface facing distally abuts the bearing surface facing proximally.

14. The system according to claim 1, wherein the axial restraint device is located on a proximal hub and the proximal hub is configured to be located on the proximal end of the tubular body.

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