Rapid aspiration thrombus removal system and method

Abstract

A dilator for facilitating intraluminal medical procedures within a neurovascular system, the dilator comprising: a flexible elongated body having a tubular body extending along a length between a proximal region and a distal region, the distal region having a tapered distal tip that tapers distally from a first outer diameter to a second outer diameter that is smaller than the first outer diameter, a single lumen extending longitudinally through the flexible elongated body to a distal opening of the tapered distal tip, wherein the tapered distal tip has a first radiopaque marker disposed at a proximal end of the tapered distal tip and a second radiopaque marker disposed at a distal end of the tapered distal tip, the first radiopaque marker and the second radiopaque marker identifying the tapered distal tip; and a proximal spine extending from the proximal region of the flexible elongated body.

Description

[0001] This application is a divisional application of the PCT international invention patent application with application number 201680018521.7, application date February 4, 2016, and invention name “Rapid aspiration thrombus removal system and method”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application Serial No. 62 / 111,481, filed on February 4, 2015, and U.S. Provisional Application Serial No. 62 / 142,637, filed on April 3, 2015, the disclosures of each of which are incorporated herein by reference in their entirety.

[0004] This application also relates to the following U.S. patent applications, which are incorporated herein by reference in their entirety: (1) U.S. patent application serial number 14 / 576,953 filed on December 19, 2014; and (2) U.S. patent application serial number 14 / 569,365 filed on December 12, 2014; (3) U.S. patent application serial number 14 / 537,316 filed on November 10, 2014; (4) U.S. patent application serial number 14 / 221,917 filed on March 21, 2014, all of which are incorporated by reference. Background Art

[0005] The present disclosure generally relates to medical methods and devices for treating acute ischemic stroke. More particularly, the present disclosure relates to methods and systems for navigating through complex anatomy to perform rapid and safe aspiration and removal of cerebral emboli.

[0006] Acute ischemic stroke is a sudden blockage of sufficient blood flow to a part of the brain, which is usually caused by a thrombus or other embolism retained or formed in one of the blood vessels supplying the brain. If this blockage cannot be resolved quickly, ischemia may cause permanent neurological impairment or death. The time limit for effective treatment of stroke is: within 3 hours for intravenous (IV) thrombolytic therapy, and within 6 hours for fixed-point intra-arterial thrombolytic therapy, or up to 8 hours for the interventional recanalization of blocked cerebral arteries. Reperfusion of the ischemic brain after this time period has no overall benefit to the patient, and may actually cause harm, because the use of fibrinolytic protein causes an increased risk of intracranial hemorrhage. Even during this period, there is strong evidence to show that the shorter the time period between symptom onset and treatment, the better the efficacy. Unfortunately, it is rare to identify symptoms, send patients to stroke treatment sites and finally treat these patients within this time limit. Despite treatment progress, stroke remains the third leading cause of death in the United States and is the main cause of serious, long-term disability.

[0007] Endovascular treatment of acute stroke includes intra-arterial administration of thrombolytic drugs (such as recombinant tissue plasminogen activator (rtPA)), mechanical removal of the blockage, or a combination of both. As mentioned above, these interventional treatments must be performed within a few hours of symptom onset. Both intra-arterial (IA) thrombolytic therapy and interventional thrombectomy involve access to the blocked cerebral artery via endovascular techniques and devices.

[0008] Similar to IV thrombolytic therapy, the limitation of IA thrombolytic therapy itself is that several hours of infusion may be required to effectively dissolve the clot. Interventional thrombectomy includes capturing and removing the clot using a snare, coil or temporary stent (also referred to as a retrievable stent device), and aspirating the clot with or without clot destruction. Retrievable stent devices are also used to quickly restore flow to the blood vessel during intervention. Hybrid procedures can also be used, which combine retrievable stent devices and aspiration via a guide catheter or via an intermediate catheter to help remove the clot and reduce the risk of distal embolism. Finally, when clot removal or dissolution cannot be performed, a balloon or stent has been used to create an artificial cavity through the clot.

[0009] In order to enter the brain anatomical structure, the interventional device is guided to the target anatomical structure from the arterial access site (typically the femoral artery) using a guide catheter or a guide sheath. During the program period that may potentially release a high level of embolism, a balloon guide catheter is often used to perform proximal carotid artery occlusion. Proximal occlusion has the effect of preventing forward flow and increasing the suction efficiency of the lumen of the guide catheter. The length of the guide is determined by the distance between the desired position of the entry site and the distal tip of the guide. The interventional device such as a guidewire, a microcatheter and an intermediate catheter for sub-selective guidance and suction is inserted through the guide and advanced to the target site. Usually, the device is used in a coaxial manner, that is, the guidewire inside the microcatheter inside the intermediate catheter is advanced to the target site in a step-by-step manner as an assembly, wherein the internal, most non-invasive element is first advanced toward the distal side and provides support for the advancement of the external element. The length of each element of the coaxial assembly takes into account the length of the guide, the length of the proximal connector on the catheter and the length required to extend from the distal end. Thus, for example, the working length of the intermediate catheter is typically 20-40 cm longer than the working length of the guide, while the working length of the microcatheter is typically 10-30 cm longer than the working length of the intermediate catheter. The guidewire is typically another 20-50 cm longer than the microcatheter.

[0010] Some exemplary problems with current technology include the time required or even the ability to access the occlusion site, the time required to restore flow or the inability to fully or even partially restore flow to the vessel, the occurrence of distal embolism during the procedure with potential negative neurological effects and procedural complications such as perforation and intracerebral hemorrhage. There is a need for a device system and method that enables rapid access, optimized aspiration of clots, distal protection during all phases of the procedure to potentially release the embolism, and safe and rapid device replacement as needed to fully restore flow to the occluded cerebral vessel. Summary of the invention

[0011] In one aspect, an intravascular access system for facilitating intraluminal medical procedures performed within the neurovascular system through an access sheath is disclosed. The system includes an aspiration or support catheter having a flexible distal lumen portion having an inner diameter defining a lumen extending between a proximal opening at a proximal end of the lumen portion and a distal opening at a distal end of the lumen portion. The catheter has a rigid spine coupled to at least the proximal end of the lumen portion and extending proximally therefrom. The system includes a dilator and a rigid dilator spine, the dilator having a flexible distal dilator portion sized to be received within the lumen of the lumen portion; and the rigid dilator spine extending proximally from the dilator portion.

[0012] The dilator spine may be aligned side by side with the spine of the catheter. The distal dilator portion may have a tapered distal tip. The dilator may have a length at least as long as the length of the catheter, such that the distal tip of the dilator protrudes from the distal opening of the lumen portion. The dilator may be generally tubular along at least a portion of the length. The proximal end of the catheter spine may include a clamping feature configured for a user to grasp in order to move the catheter through the access sheath. The proximal end of the dilator spine may include a tab configured to lock with the clamping feature on the catheter spine. When the catheter and the dilator are in a locked configuration, they can be advanced through the access sheath as a single unit. The clamping feature and the dilator tab may be removably coupled so that in the locked configuration, the dilator tab engages the clamping feature, and in the unlocked configuration, the dilator tab disengages from the clamping feature. The dilator tab may be fixed to the dilator, or may be slidable on the dilator to accommodate different relative positions between the dilator and the catheter. The distal dilator portion may include one or more detents on an outer surface configured to lock with correspondingly shaped surface features on an inner surface of the lumen of the luminal portion through which the dilator portion extends. The dilator spine and the catheter spine may have similar stiffness and kink resistance. The dilator may have visual markings on the distal and / or proximal ends of the distal tip. The distal region of the dilator may be more flexible and increase in stiffness toward the proximal region of the dilator. The catheter spine and the dilator spine may be configured to cause bidirectional sliding movement of the luminal portion through the lumen of the access sheath and navigate the luminal portion into the cerebral blood vessels to reach a treatment site.

[0013] In an interrelated aspect, an intravascular access system for facilitating intraluminal medical procedures within a neurovascular system is disclosed, which has an access sheath and an aspiration or support catheter. The access sheath has a sheath body having an inner diameter defining a lumen between a proximal end and a distal end of the sheath body. The sheath body has at least one opening from the lumen near a distal region of the sheath body. The aspiration or support catheter includes a flexible distal lumen portion having an outer diameter sized to be inserted through the lumen of the access sheath, an inner diameter defining a lumen extending between a proximal opening at the proximal end of the lumen portion and a distal opening at the distal end of the lumen portion, and a length between the proximal opening and the distal opening. The aspiration or support catheter includes a rigid spine coupled to at least the proximal end of the lumen portion and extending proximally therefrom. The rigid spine is configured to cause a bidirectional sliding motion of the lumen portion through the lumen of the access sheath and out of the at least one opening to navigate the lumen portion into a cerebral vessel to reach a treatment site. When the distal end of the lumen portion is extended into a cerebral vessel to reach a treatment site, a portion of the outer diameter of the lumen portion is fluidly sealed with the inner diameter of the access sheath.

[0014] The lumen portion and the sheath body can be concentrically aligned, and the lumen of the lumen portion and the lumen of the sheath body form a continuous suction lumen from the distal end of the lumen portion to the proximal end of the sheath body. The continuous suction lumen can be used to suction fluid and debris from the distal opening of the lumen portion. The continuous suction lumen can deliver material through the distal opening of the lumen portion. The continuous suction lumen can form an increasing portion of diameter, where the lumen of the lumen portion merges into the lumen of the sheath body. The lumen of the lumen portion can be shorter than the lumen of the sheath body. When the lumen portion extends distally beyond the at least one opening of the sheath body, the lumen portion and the sheath body can form an overlapping area. The outer diameter of the lumen portion can approach the inner diameter of the lumen of the sheath body, so that a seal is formed by the overlapping area. The seal can be configured to be able to seal a vacuum up to 25inHg or up to 28inHg. The seal in the overlap region may be configured to seal against pressures up to 300 mmHg, or up to 600, or up to 700 mmHg.The seal may be located distal to a proximal end of the lumen portion and proximal to the at least one opening of the sheath body.

[0015] The system may also include a sealing element positioned on the outer surface of the lumen portion. The sealing element may include an increasing diameter or protruding feature in the overlapping area. The sealing element may include one or more external ridge features. When the lumen portion is inserted into the lumen of the sheath body, the one or more ridge features may be compressible. The sealing element may include one or more inclined surfaces biased against the inner surface of the lumen of the sheath body. The sealing element may include one or more expandable members actuated to seal. The sheath body may have an outer diameter suitable for insertion into the carotid artery. The outer diameter of the sheath body may be between 5Fr and 7Fr.

[0016] The sheath body can have a length between a proximal end and a distal end suitable for positioning the distal end of the sheath body at the petrous portion of the internal carotid artery from a transfemoral approach. The length of the sheath body can be between 80 cm and 105 cm. The length of the lumen portion can be between 10 cm and 25 cm. The length of the lumen portion can be less than the length of the sheath body so that when the catheter is retracted into the sheath body, a seal is maintained between the overlapped region of the lumen portion and the inner diameter of the sheath body.

[0017] The spine may be longer than the entire length of the sheath body. The lumen portion may include three or more layers, including an inner lubricating lining, a reinforcing layer, and an outer sheath layer. The outer sheath layer may be composed of discontinuous portions of polymers having different hardnesses, compositions, and / or thicknesses to vary flexibility along the length of the distal lumen portion. The outer diameter of the distal lumen portion may be sized to be used for navigation into a cerebral artery. The inner diameter of the distal lumen portion may be between 0.040" and 0.088". The outer diameter of the lumen portion may approach the inner diameter of the sheath body to create a sealing area at an overlapping region while still allowing the catheter to move through the sheath body. The catheter may be tapered toward the distal opening so that the distal end of the lumen portion has a smaller outer diameter than a more proximal region of the lumen portion, near which the lumen portion is sealed to the sheath body. The distal region of the sheath body may include an occluding element. The distal region of the sheath body may include an expanded distal tip. The at least one opening from the lumen may include a side opening located a distance away from the distal tip of the sheath body. The distal tip of the sheath body may also include a bevel feature configured to angle the catheter away from the longitudinal axis of the sheath body lumen and out through the at least one opening.

[0018] The spine may be longer than the entire length of the sheath body. The spine may be a wire having an outer diameter from 0.014" to 0.018". The spine may be a hypotube having a guidewire channel extending therethrough. The spine may be a ribbon having an outer dimension of a thickness from 0.010" to 0.025". The ribbon may be curved along at least a portion of an arc. The spine may be configured to rotate the lumen portion about the longitudinal axis of the access sheath. The spine may be eccentrically coupled to the lumen portion, and the spine extends proximally from the lumen portion to the exterior of the proximal end of the sheath body. The proximal end of the lumen portion may have an angled cutout. The angled cutout may be generally planar or curved. The sheath body may have one or more visual markings on a distal region of the sheath body. The distal lumen portion may have one or more visual markings at a distal region of the lumen portion, a proximal region of the lumen portion, or both. The one or more visual markings on the sheath body and the one or more visual markings on the lumen portion may be visually different. The spine can have one or more visual markings. The one or more visual markings of the spine can indicate an overlap between the distal lumen portion and the sheath body. The one or more visual markings of the spine can be positioned such that when the visual marking of the spine is aligned with a portion of the access sheath, the catheter is positioned at a distal-most position with a minimum overlap length required to create a seal between the catheter and the sheath body.

[0019] The system may also include a dilator having a flexible distal dilator portion having a distal tip and sized to be received within the lumen portion of the catheter. The dilator may be a tubular element along at least a portion of its length. The dilator may be a solid rod formed of a ductile material configured to be shaped by a user. The dilator may also include a rigid dilator spine extending proximally from the dilator portion. The dilator spine may be coaxial and may have a lumen extending through it. The dilator spine may be eccentric. When used, the dilator spine may be aligned side by side with the spine of the catheter. The distal tip of the dilator may be conical. The dilator may have a length at least as long as the length of the catheter so that the distal tip protrudes from the distal opening of the lumen portion. The proximal end of the spine may include a clamping feature configured for a user to grasp in order to move the catheter through the access sheath. The proximal end of the dilator spine may include a tab configured to lock with the clamping feature on the catheter spine. When the catheter and the dilator are in a locked configuration, they can be advanced through the sheath body as a single unit. The clamping feature and the dilator tab can be removably coupled such that in the locked configuration, the dilator tab engages the clamping feature, and in the unlocked configuration, the dilator tab disengages from the clamping feature. The dilator tab can be fixed to the dilator, and / or can be slidable on the dilator to accommodate different relative positions between the dilator and the catheter.

[0020] The distal dilator portion may include one or more detents on an outer surface configured to lock with correspondingly shaped surface features on an inner surface of a lumen of the lumen portion through which the dilator portion extends. The dilator spine and the catheter spine may have similar stiffness and kink resistance. The dilator may have visual markings on the distal and / or proximal ends of the distal tip. The distal region of the dilator may be more flexible and increase in stiffness toward a proximal region of the dilator.

[0021] The access sheath may also include a connector that connects the proximal end of the sheath body to a proximal hemostasis valve. The proximal hemostasis valve may have an adjustable opening that is sized to be large enough to allow the catheter to be removed without dislodging any clot thereon. When used with the access sheath, the rigid spine of the catheter may extend proximally from the lumen portion through the access sheath lumen and out of the proximal hemostasis valve of the access sheath. The connector may provide a connection of the proximal end of the sheath body to a suction line. The connector may have a large bore inner lumen and be connected to a large bore suction line. The suction line may be connected to a suction source. The suction source may be an active suction source. The suction line may be connected to a forward instillation or flushing line. The access sheath may also include a proximal extension portion so that when the distal lumen portion of the catheter is retracted from the sheath body lumen, it remains within the proximal extension portion. The inner diameter of the lumen portion may be sized to allow placement of an interventional device through the lumen portion.

[0022] Other features and advantages will be apparent from the following description of various embodiments, illustrating by way of example the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is an exploded view of a device system for accessing and removing a brain occlusion from a femoral artery access site to treat acute ischemic stroke;

[0024] Figure 2A Shows Figure 1 The components of the system are positioned in the patient from a transfemoral approach to treat the occlusion;

[0025] Figure 2B yes Figure 2A A detailed view of a portion of the system taken along circle BB;

[0026] Figure 3 Shown being used via a transcervical access site Figure 1 Components of the system;

[0027] Figure 4 An embodiment of an access sheath is shown;

[0028] Figure 5 Shown as a separate, removable component Figure 4 Embodiments of a proximal portion of an access sheath;

[0029] Figure 6 shows the minimization by Figure 4 Embodiments of a connector having a flow resistance of the access sheath into the proximal portion;

[0030] Figure 7 An embodiment of an access sheath with an occluding balloon is shown;

[0031] Figures 8A-8B An embodiment of a sealing element between an access sheath body and a lumen portion of a catheter extending therethrough is shown;

[0032] Fig. 9 An embodiment of a microcatheter and retrievable stent device positioned via a spine-bearing catheter is shown;

[0033] Figures 10A-10C An embodiment of an expandable portion on a retrievable stent device is shown;

[0034] Fig.11 An embodiment of an aspiration system for use with the systems described herein is shown;

[0035] Fig. 12A An embodiment of a catheter system with spine for use with the systems described herein is shown;

[0036] Fig. 12B Shows Fig. 12A a spine-bearing catheter system having a spine-bearing dilator extending through a lumen of the spine-bearing catheter;

[0037] Fig. 12C Shows Fig. 12A a catheter system with a spine extending through a side opening of an embodiment of an access sheath;

[0038] Fig.13 It is around Fig. 12B A cross-sectional view taken along line AA;

[0039] Fig.14 It is around Fig. 12B A cross-sectional view taken along line BB;

[0040] Fig.15A An embodiment of a spine-containing aspiration catheter-dilator system having a spine-containing catheter and a spine-containing dilator in a locked configuration is shown.

[0041] Fig. 15B A spine-bearing aspiration catheter-dilator system is shown with a spine-bearing catheter and a spine-bearing dilator in an unlocked configuration;

[0042] Fig.16 An embodiment of a catheter system with a spine extending distally to an access sheath for treating emboli in a cerebral vessel is shown. DETAILED DESCRIPTION

[0043] One of the major drawbacks of current acute stroke interventional procedures is the time required to restore blood perfusion to the brain. This time includes the time required to access one or more occluded sites in the cerebral arteries, as well as the time required to completely remove the occlusion in the artery. Since it is often the case that more than one attempt must be made to completely remove the occlusion, reducing the number of attempts and reducing the time required to change devices for additional attempts are important factors in minimizing the total time. In addition, each attempt is associated with potential procedural risks caused by advancing the device in the fragile cerebrovascular system.

[0044] Disclosed herein are methods and devices that enable safe and rapid access to the complex neurovascular anatomy of the brain and intracranial arteries and removal of occlusions. The methods and devices include one or more access devices, catheters, and occlusion removal thrombectomy devices. Also disclosed are methods and devices that provide active suction and / or passive flow reversal to facilitate occlusion removal and minimize distal embolism. The system provides a degree of flow control to the user to meet the specific hemodynamic requirements of the cerebrovascular system. The system described herein provides excellent ease of use in that a single operator can operate the disclosed system using a single point of continuous suction to quickly and safely perform replacements without switching. The higher efficiency of the suction force of the system described herein reduces distal embolic debris and increases the rate of "one-time" thrombectomy.

[0045] It should be appreciated that, although some embodiments are specifically described with respect to suctioning neurovascular anatomical structures, the embodiments are not limited thereto, but may also be applied to other uses. For example, the suction catheter with spine and one or more components of the access system described herein may be used to deliver a working device to a target vessel of a coronary artery anatomical structure or other vascular system anatomical structure. It should be appreciated that, in the case where the phrase "suction catheter" is used herein, such a catheter may be used for other purposes besides suction, such as delivering fluid to a treatment site or providing a pipeline as a support catheter to facilitate and guide the delivery or replacement of other devices such as guidewires or interventional devices. Alternatively, the access system need not be limited to the vascular system, and may be used to access other parts of the body outside the vascular system. It should also be appreciated that references to specific features, structures, configurations, characteristics, or implementations or embodiments throughout this specification may be combined in any suitable manner. The use of relative terms throughout the description may indicate relative positions or directions. For example, "distal" may indicate a first direction away from a reference point. Similarly, "proximal" may indicate a position in a second direction opposite to the first direction. However, such terms are provided to establish a relative frame of reference and are not intended to limit the use or orientation of the anchor delivery system to the specific configurations described in the various embodiments below.

[0046] Figure 1 A device system for accessing and removing a cerebral occlusion from a femoral artery access site to treat acute ischemic stroke is shown. The system 100 includes an access sheath 220, a sheath dilator 250, a guidewire 270, one or more aspiration or support catheters 320 with spines, a dilator 340, a microcatheter 400, and a retrievable stent device 500, each of which will be described in more detail below. In addition, the system 100 may include one or more arterial access sheath systems 200, which include an access sheath 220, one or more sheath dilators 250, and a sheath guidewire 270. The system 100 may include one or more catheter systems 300 with spines, which include aspiration or support catheters 320 with spines, a tapered dilator 340, and alternatively, a catheter cleaning tool 350. The catheter system 300 with spines may include nested catheters with spines to expand to a distal site. The system 100 may include an access sheath system 200, a tapered catheter system 300, a microcatheter 400, and a retrievable stent device 500.

[0047] Figure 2A Some elements of the system are shown in place in a patient to treat an occlusion from a transfemoral approach. An access sheath 220 can be inserted through a femoral artery insertion site positioned so that the distal tip of the access sheath 220 is located at or near the petrous portion of the internal carotid artery ICA. A spine-carrying aspiration catheter 320 can be positioned so that the distal tip is located at the occlusion surface in the artery. In some implementations, the access sheath 220 can be inserted through a direct puncture in the wall of the common carotid artery and advanced into the internal carotid artery, rather than via a transfemoral approach (see FIG. Figure 3 ).

[0048] As in the detailed Figure 2B As more clearly seen in FIG. 2 , the access sheath 220 can have a sheath body 222 and an inner lumen 223 extending between the proximal and distal regions of the sheath body 222. The spine-bearing aspiration catheter 320 is sized to extend through the inner lumen 223 of the access sheath 220 such that the distal region of the catheter 320 extends beyond the distal region of the access sheath 220. The catheter 320 is disposed within the Figure 2B 221 as exiting the lumen 223 of the sheath body 222 through the distal opening 221. However, it should be appreciated that the sheath body 222 may have one or more side openings proximal to the distal region of the body 222 through which the catheter 320 may pass (see Fig. 12C ), which will be described in more detail below.

[0049] Still reference Figure 2B, the spine-bearing aspiration catheter 320 can include a relatively flexible distal lumen portion 322 coupled to a rigid and kink-resistant proximal spine 330. The distal lumen portion 322 can have an inner lumen 323 extending between the proximal and distal ends of the lumen portion 322. The lumen 323 of the catheter 320 can have a first inner diameter, and the lumen 223 of the access sheath 220 can have a second, larger inner diameter. The lumens 223, 323 are fluidly connected and continuous so that it is possible for fluid to flow into and / or out of the system, for example by applying suction from a suction source coupled to the system via a connector 226 on the access sheath 220. The overlap region 120 between the distal portion of the sheath body 222 and the lumen portion 322 of the catheter 320 is sized and configured to create a seal that allows a continuous aspiration lumen from the distal tip region of the spine-bearing catheter 320 to the proximal sheath connector 226. If the sheath body 222 has a side opening through which the distal lumen portion 322 of the catheter 320 extends, the seal created at the overlap region 120 between the sheath body 222 and the lumen portion 322 is located proximal to the side opening.

[0050] The key dimensions that affect the suction force through the tube include radius (r), pressure (P), viscosity (n) and length (L), where flow rate = Q = πr 4(ΔP) / 8nL. The change in radius increases the flow rate to the fourth power and the length is inversely proportional to the flow rate. As will be described in more detail below, the aspiration catheter has an over-the-wire portion that is part of the total distance required to reach the target site. This configuration greatly speeds up the time required to retract and re-advance the catheter. In addition, the system described herein can provide a significantly increased radius and lumen area for aspirating clots and a significantly shorter length, particularly compared to existing systems in which the aspiration lumen extends along the entire inner diameter of the aspiration catheter. In the system described herein, most of the aspiration lumen has the radius of the procedure sheath. The catheter 320 is smaller in diameter than the guide, but increases in lumen diameter when it reaches the lumen of the passage sheath 220, allowing greater suction force to be applied to most of the length of the lumen system. In addition, the total length of this narrow diameter region of the catheter 320 is much shorter than the total length of the passage sheath. The proximal spine 330 of the catheter 320 has a length and structure extending through the lumen 223 of the access sheath 220 to the proximal end of the system, so that it can be used to advance and retract the catheter 320 through the lumen 223 of the sheath 220. However, the spine 330 of the suction catheter 320 only occupies a small part of the lumen space of the system, resulting in an increase in the lumen area used for suction. The increased lumen area used for suction increases the time spent on suction occlusion and increases the possibility of removing the occlusion in a single suction attempt. When a device such as a microcatheter or a tapered dilator is coaxially positioned in the catheter 320 with the spine and the access sheath 220, the increasing lumen diameter also increases the annular area that can be used to flush contrast agents, saline or other solutions forward. This can increase the ease and ability of performing angiography during device navigation.

[0051] Current stroke interventions pose a risk of distal emboli being released. For example, during attempts to remove or dissolve clot blockages in cerebral arteries, there is a significant risk of thrombus rupture producing embolic particles that can migrate downstream into the occluded or other vessels and impair cerebral perfusion. In carotid artery stenting (CAS), embolic protection devices and systems are often used to reduce the risk of embolic material entering the cerebral vasculature. Types of devices include intravascular distal filters, and reverse flow or static flow systems. Unfortunately, these types of embolic protection systems are not used for interventional treatment of acute ischemic stroke due to fragile anatomical structures and access challenges and the need for rapid intervention. The stroke intervention period when flow is restored is often considered an important time because the brain is now being perfused with blood. However, this is also a period of embolic risk. When there is a blockage in the artery, there is no flow. Therefore, any embolic debris generated by passing the occlusion with a guidewire and / or microcatheter or deploying a retrievable stent device through the occlusion remains stagnant. However, when flow is restored to the artery, the embolism can now flow antegrade to the distal vascular region.

[0052] When the retrievable stent device is being pulled back into the guide or catheter, the second period of embolism risk occurs. In existing methods and devices, suction is applied to the intermediate catheter when the retrievable stent device is retracted into the catheter, or the catheter and the retrievable stent device are pulled back into the guide together, and suction is applied to the guide catheter. Both suction points through the catheter and through the guide can be used to reduce the risk of distal embolism during the critical step of drawing out the occlusion from the patient by the guide. Usually, two people are needed to achieve two suction points, or suction is performed sequentially from the catheter and then from the guide, which may cause interruption or suboptimal suction of suction. In the disclosed system and method, during the advancement of the device, at the critical time of flow recovery, and during the entire time of removing the occlusion with a single suction point, reverse flow can be applied to the target site.

[0053] In aspects of the present disclosure, the suction level can be varied from a low level that achieves adequate protection of distal embolism to a higher level that provides effective suction removal of the occlusion. This aspect allows distal protection without high levels of blood loss, but allows the strong suction force required to remove the occlusion.

[0054] In another aspect, methods and apparatus are disclosed for additionally providing active aspiration or passive retrograde flow during a procedure to remove thrombi and minimize distal embolism. The system provides the user with a degree of blood flow control to meet the specific hemodynamic requirements of the cerebrovascular system. The system may include a flow controller that allows the user to control the timing and pattern of aspiration.

[0055] In another aspect, methods and apparatus are disclosed for additionally providing a flushing step to minimize embolism in the system and increase visibility of particles in the system during use.

[0056] The following description provides detailed implementations and benefits of each aspect of the disclosed invention.

[0057] Referring again to the embodiment of the embodiment showing the access sheath 220 Figure 1 The sheath 220 may include a sheath body 222 as the insertable portion of the sheath 220 (i.e., the portion that is inserted into the patient), a proximal connector 226, an aspiration line 230, a proximal hemostasis valve 234, and an irrigation line 236. The sheath 220 may also include a proximal extension 240, and may also include a valve on the connector 226 to fluidically isolate the sheath body 222 from the proximal portion 240 of the access sheath 220. The access sheath 220 may be accompanied in the kit by one or more dilators 250, and a sheath guidewire 270.

[0058] The diameter of the sheath body 222 is suitable for insertion into the carotid artery, and it has an inner lumen 223 of a size suitable for providing a passage for a catheter for treating the occlusion. In one embodiment, the sheath body 222 can have an inner diameter of about 0.074" and an outer diameter of about 0.090" (corresponding to a 5Fr sheath size), an inner diameter of about 0.087" and an outer diameter of about 0.104" (corresponding to a 6Fr sheath size), or an inner diameter of about 0.100" and an outer diameter of about 0.177" (corresponding to a 7Fr sheath size). The length of the sheath body 222 is configured to enable the distal tip of the sheath body 222 to be positioned as distally as the petrous portion of the internal carotid artery. In one embodiment, the length of the sheath body 222 is suitable for a transfemoral approach, which is in the range of 80 to 90 cm, or up to about 100 cm, or up to about 105 cm. In one embodiment, the length of the sheath body 222 is suitable for a transjugular approach to the petrous ICA, which is in the range of 20 to 25 cm. In one embodiment, the length of the sheath body 222 is suitable for a transcervical approach to the CCA or proximal ICA, which is in the range of 10-15 cm. The sheath body 222 is configured to assume and navigate through the bends of the vascular system and receive high suction without kinking, collapsing, or causing vascular trauma.

[0059] The sheath body 222 can be constructed in two or more layers. The inner liner can be constructed of a low friction polymer such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene) to provide a smooth surface for advancing the device through the inner lumen. The outer sheath material can provide mechanical integrity to the inner liner and can be constructed of materials such as PEBAX, thermoplastic polyurethane, polyethylene, nylon, etc. A third layer can be incorporated, which can provide reinforcement between the inner liner and the outer sheath. The reinforcement layer can prevent flattening or kinking of the inner lumen of the sheath body 222 to allow the device to navigate unimpeded through bends in the vascular system and unimpeded suction or reverse flow. The sheath body 222 can be circumferentially reinforced. The reinforcement layer can be made of metals such as stainless steel, Nitinol, Nitinol braid, spiral tape, spiral wire, cut stainless steel, etc., or rigid polymers such as PEEK. The reinforcement layer can be a structure such as a coil or braid or a pipe that has been laser cut or mechanically cut to have flexibility. In another embodiment, the reinforcement layer can be a cut hypotube, such as a Nitinol hypotube, or a cut rigid polymer, etc.

[0060] The flexibility of the sheath body 222 can vary over its length, with the flexibility increasing toward the distal portion of the sheath body 222. The change in flexibility can be achieved in various ways. For example, the outer sheath can change hardness and / or material at various portions. A lower hardness outer sheath material can be used in the distal portion of the sheath compared to other portions of the sheath. Alternatively, the wall thickness of the sheath material can be reduced, and / or the density of the reinforcement layer can be varied to increase flexibility. For example, the pitch of the coil or braid can be stretched, or the cutting pattern in the tubing can be varied to have greater flexibility. Alternatively, the reinforcement structure or material can vary over the length of the sheath body 222. In one embodiment, the distal-most portion has a force between 50 and 300 N-mm 2 The bending stiffness (E*I) of the sheath body 222 is in the range of 500 to 1500 N-mm 2 , where E is the elastic modulus and I is the area moment of inertia of the device. In another implementation, there is a transition portion between the most distal flexible portion and the proximal portion, with one or more portions of varying flexibility between the most distal portion and the remainder of the sheath body 222. In this embodiment, the most distal portion is about 2 cm to about 5 cm, the transition portion is about 2 cm to about 10 cm, and the proximal portion occupies the remainder of the sheath length.

[0061] The tip of the sheath body 222 may include one or more distal radiopaque markers 224 (see Figure 1 ). In one embodiment, the radiopaque tip marker 224 is a metal band embedded near the distal end of the sheath body 222, such as a platinum-iridium alloy. Alternatively, the access sheath tip material can be a separate radiopaque material, such as a barium polymer or a tungsten polymer blend. The distal region of the sheath body 222 is also an area of ​​overlap region 120 that allows for a seal between the catheter 320 and the sheath body 222 to create a continuous suction lumen. Therefore, the outer diameter of the lumen portion 322 of the suction catheter 320 approaches the inner diameter of the distal region of the lumen 223 of the sheath body 222, thereby forming a seal. The relative position of the seal formed can vary depending on the position at which the suction catheter 320 leaves the lumen 223 of the sheath body 222 and the position of the opening from the sheath body 222, as described in more detail below. For example, if the sheath body 222 has an opening at the distal tip, the seal can be located closer to the distal end of the sheath body 222 than if the sheath body 222 has one or more side openings in the distal region of the sheath body 222 for the catheter 320 to exit the lumen 223.

[0062] Reference again Figure 1, the access sheath 220 may also include a connector 226 that connects the proximal end of the sheath body 222 to the proximal hemostasis valve 234 and also provides a connection to the aspiration line 230. The connector 226 may have a large bore inner lumen and is connected to the large bore aspiration line 230. In one embodiment, the inner lumen of the connector 226 is at least 0.080". In one embodiment, the inner lumen of the aspiration line 230 is at least 0.080". The aspiration line 230 may terminate in a stopcock, a female luer connector, or other connector 232 that allows connection to a suction source. In one embodiment, the aspiration source is an active aspiration source, such as a syringe or a pump. In another embodiment, the aspiration source is a reverse flow shunt line, such as described in U.S. Patent No. 8,157,760 and U.S. Patent Publication No. 2010 / 0217276, both of which are incorporated herein by reference. The large bore aspiration line 230 may be configured to resist collapse. For example, the suction line 230 can be a thick-walled polymer tubing or a reinforced polymer tubing. The suction line valve 232 enables the line 230 to be opened or closed. In one embodiment, the valve 232 also allows the connection of one or more additional fluid lines for connecting a forward instillation or flushing line for contrast agent or saline injection. As an example, the valve 232 can be a stopcock manifold commonly used in interventional procedures to allow multiple connections. The connector 226 can also include a device to secure the access sheath 220 to the patient to reduce the risk of the sheath coming out in this case. For example, the connector 226 can include one or more suture eyelets 233.

[0063] Still reference Figure 1, the proximal end of the access sheath 220 can terminate in a proximal hemostasis valve 234. The valve 234 allows the device to be introduced into the vascular system through the sheath 220 while preventing or minimizing blood loss and preventing the introduction of air into the access sheath 220. The hemostasis valve 234 can include a flushing line 236 or a connection to a flushing line 236 so that the sheath 220 can be flushed with saline or radiopaque contrast agent as needed during the procedure. The flushing line 236 can also be used as a second suction point during part of the procedure, as described more fully below. The hemostasis valve 234 can be a static sealing passive valve, or an adjustable opening valve, such as a Tuohy-Borst valve or a rotary hemostasis valve (RHV). The hemostasis valve 234 can be integral with the access sheath 220, or the access sheath 220 can terminate in a female luer adapter on the proximal end, and a separate hemostasis valve 234 component (e.g., a passive sealing valve, a Tuohy-Borst valve, or a rotary hemostasis valve) can be attached to the female luer adapter. In one embodiment, valve 234 has an adjustable opening that opens large enough to allow removal of a device with an adhered clot on the tip without causing the clot to dislodge at valve 234 during removal. Alternatively, valve 234 is removable and is removed when the catheter tip is removed from sheath 220 to prevent the clot at valve 234 from dislodging.

[0064] Reference again Figure 1 , the arterial sheath system 200 may include one or more sheath dilators 250 and a sheath guidewire 270. The sheath guidewire 270 may be first inserted into the artery using standard vascular access techniques (e.g., micropuncture techniques or modified Seldinger techniques). The sheath dilator 250 allows the access sheath 220 to be smoothly inserted through the puncture site in the arterial wall. The dilator 250 may be inserted into the access sheath 220, and then the two components may be inserted into the artery together on the sheath guidewire 270. The distal end 256 of the dilator 250 may be generally conical so as to allow the dilator 250 to dilate the needle puncture site when it is inserted into the artery through the arterial wall. The tapered distal end 256 may have a total angle (relative to the longitudinal axis of the dilator) generally between 6 and 12 degrees, with an arcuate leading edge.

[0065] The inner lumen of the dilator 250 can accommodate the sheath guidewire 270 and can have an inner diameter between 0.037" and 0.041" to correspond to the sheath guidewire 270 between 0.035" and 0.038". Alternatively, the inner lumen of the dilator 250 can be between 0.020" and 0.022" to accommodate the sheath guidewire 270 between 0.014" and 0.018". Alternatively, the dilator 250 can be a two-part dilator having an inner dilator and an outer dilator. The outer dilator can have an inner diameter between 0.037" and 0.041", and the inner dilator can have an inner diameter between 0.020" and 0.022". In use, the sheath 220 can be inserted into the artery together with the outer dilator having the sheath guidewire 270 between 0.035" and 0.038". The sheath guidewire 270 may then be removed and replaced with an inner dilator and a smaller guidewire of between 0.014" and 0.018", and the access sheath 220 may then be further advanced distally to the desired location in the carotid artery.

[0066] In order to insert the arterial sheath 220 initially on the sheath guidewire 270 into the artery, the dilator taper 256 can have a certain rigidity and taper angle to provide sufficient expansion force on the arterial puncture site. However, in order to safely reach the petrous part of the ICA, it may be desirable to have such a sheath dilator 250, which has a softer and / or longer taper at the distal end than that used for the initial arterial access. In one embodiment, the access sheath system 200 may include two or more tapered dilators. The first tapered dilator can be used with an arterial access device to enter the artery, and therefore the size and structure are determined in a manner similar to a standard introducer sheath dilator. Exemplary materials that can be used for tapered dilators include, for example, high-density polyethylene, 72D PEBAX, 90D PEBAX, or equivalent rigidity and lubricity materials. The second tapered dilator can be provided with a softer distal portion or a distal portion with a lower bending rigidity and / or a longer tapered portion length relative to the distal portion of the first tapered dilator. That is, the second dilator has a distal region that is softer, more flexible, or more easily segmented or bent than the corresponding distal region of the first dilator. Thus, the distal region of the second dilator is more easily bent than the corresponding distal region of the first dilator. In one embodiment, the distal portion of the first dilator has a force between 50 and 100 N-mm 2 The distal portion of the second dilator has a bending stiffness in the range of 5 to 15 N-mm 2 A second dilator (which has a distal portion with lower bending stiffness) can be exchanged with the initial first dilator so that the access sheath 220 can be advanced into the internal carotid artery and bypass the curvature in the artery without excessive force or trauma to the vessel due to the softer distal portion of the second dilator.

[0067] The distal portion of the soft second dilator can be, for example, 35 or 40D PEBAX, with the proximal portion made of, for example, 72DPEBAX. One or more intermediate mid-sections may be included on the second dilator to provide a smooth transition between the soft distal portion and the harder proximal portion. In one embodiment, the two dilators have an inner diameter between 0.037" and 0.041". In an alternative embodiment, the first dilator has an inner diameter between 0.037" and 0.041", and the second dilator has an inner diameter between 0.020" and 0.022". In yet another embodiment, the second dilator is a two-part dilator having an inner dilator and an outer dilator as described above. In one embodiment, one or both dilators may have a radiopaque tip marker 224 so that the dilator tip position is visible during fluoroscopy. In one variation, the radiopaque marker 224 is a portion of tungsten-loaded PEBAX or polyurethane that is heat welded to the distal tip of the dilator. Other radiopaque materials may similarly be used to produce a radiopaque marker 224 at the distal tip.

[0068] In one embodiment, the access sheath 220 includes a proximal extension 240 extending between the connector 226 and the proximal hemostasis valve 234. In a transcervical configuration of the system, it may be desirable to move the proximal hemostasis valve 234 away from the distal tip of the access sheath 220, effectively extending or lengthening the proximal portion of the access sheath outside the body while maintaining the length of the insertable sheath body portion 222. This allows the user to insert the device into the proximal hemostasis valve 234 of the access sheath 220 from a point further away from the target site and therefore away from the x-ray source and / or image intensifier used for fluoroscopic imaging of the target site, thereby minimizing radiation exposure to the user's hands and his or her entire body. In this embodiment, the proximal extension 240 can be in a range of between 10 and 25 cm, or between 15 and 20 cm. In a transcervical or transfemoral configuration, it may also be desirable to provide a portion of the access sheath 220 that is fluidly connected to the access sheath aspiration line, but which can extend proximally from the aspiration line connection. This will allow the user to pull the device out of the blood flow from the sheath tip to the aspiration line without completely removing the device from access sheath 220.

[0069] In alternative embodiments, it may also be desirable to intermittently isolate the proximal portion 240 from the sheath body 222. In one embodiment, as Figure 4As shown in , the connector 226 includes a valve 242 that can close the fluid connection between the sheath body 222 and the proximal portion 240 of the access sheath 220 (including the aspiration line 230, the proximal extension 240 and the proximal hemostasis valve 234). This can allow the distal portion of the catheter, a retrievable stent device, or other thrombus removal device to be pulled into the proximal extension 240, the valve 242 to close to fluidly isolate the sheath body 222 from the proximal portion of the sheath, and then the proximal hemostasis valve 234 is widely opened or removed, or the entire proximal extension 240 of the sheath 220 is removed, without bleeding from the artery of the sheath 220. The proximal extension 240 can be at least as long as the distal lumen portion 322 of the spine-bearing catheter 320 so that the distal lumen portion 322 can be fully pulled into the proximal extension 240 and the valve 242 closed before the proximal hemostasis valve 234 is opened widely to completely remove the catheter 320 from the sheath 220.

[0070] Alternatively, after a thrombectomy device or other interventional device is pulled into the proximal extension 240 and the sheath body 222 is closed via valve 242, a portion of the thrombectomy device (e.g., the distal lumen portion 322 of the aspiration catheter 320) can remain in the proximal extension 240 and be flushed or otherwise cleaned by creating flow from the flush line to the aspiration line to dislodge the clot without completely removing the device 320 from the access sheath 220. This ability to flush and clean the thrombectomy device without completely removing the thrombectomy device can reduce bleeding, time, and the risk of air embolism during steps between thrombus removal attempts. Moreover, retracting the thrombectomy device into the proximal extension 240 while flushing and cleaning without completely removing it from the sheath body 222 also minimizes operator and staff exposure to blood and debris associated with device cleaning. In any of these embodiments, the proximal extension tubing is transparent so that flushing solution and the presence / absence of embolic debris or air are clearly visible through the tubing.

[0071] The proximal extension 240 of the access sheath 220 can be provided as a separate, removable component that can be attached to any sheath using a standard connection on the proximal end. Figure 5As shown in , the proximal component 280 includes a connector 285 that can be attached to the proximal connector 15 of the standard sheath 10. The connected components can produce an assembly having the configuration and features of the access sheath 220. In this embodiment, the user can select from any of several already available sheaths of appropriate length, shape, and mechanical properties for the procedure, and perform the steps of the procedure described in the present disclosure. The removable proximal component 280 may include a Y-arm connector 226, an aspiration line 230, a proximal extension 240, a proximal hemostasis valve 234 and an irrigation line 236, and valve connectors 232 and 238 that terminate the aspiration line 230 and the irrigation line 236, respectively. The connector 285 can be connected to the proximal connector 226 on the sheath 220. In the example shown in FIG. Figure 6 In the illustrated embodiment, the connector 285 is configured to minimize resistance to flow through the sheath 10 and into the proximal portion 280. For example, instead of a standard male-female luer connection, the connector 285 may include: an adapter 60 having an inner lumen and surface that mates with a standard female luer connector 62 typically located on a sheath; a sealing element 64 that seals between the adapter 60 and the sheath female luer connector 62; and a rotating nut 66 that engages the threaded elements of the female luer connector 62 and couples the adapter 60 and the luer connector 62 together so that the seal 64 is compressed and can seal against fluid and air vacuum and pressure. Again, referring to Figure 5 The proximal component 280 may also include a valve 242 on the Y-arm connector 226 so that when the proximal component 280 is attached to the sheath 10, the proximal portion may selectively open or close fluid connection with the sheath 10. A similar type of connection may be made for the connector 232 that connects the sheath aspiration line 230 to the aspiration source.

[0072] In a preferred embodiment, for an overall length of approximately 34 cm, the proximal connection has a proximal extension length of approximately 22 cm, a Y-arm connector of approximately 7 cm, and a proximal hemostasis valve of approximately 5 cm in length.

[0073] It may be desirable to temporarily occlude the carotid artery during an intervention to prevent antegrade flow of the embolus during part of the procedure. Figure 7 , the access sheath 220 includes an occlusion balloon 246 on the distal tip of the sheath body 222. An additional lumen in the sheath body 222 can be connected to an inflation line 248 and fluidly connect the balloon 246 to the inflation line 248. An inflation device is attached to the inflation line 248 to inflate the occlusion balloon 246. In this embodiment, the balloon 246 is inflated when occlusion of the carotid artery is desired.

[0074] In some cases, it is desirable to keep the sheath tip as small as possible during sheath insertion to minimize the diameter of the arterial puncture, but to expand the opening of the sheath 220 after it has been inserted into the blood vessel. At least one purpose of this feature is to minimize the impact or generation of distal embolism during the pulling back of the aspiration catheter 320 or other thrombus removal device into the sheath 220. During the thrombus removal procedure, the thrombus can be "pulled back" into the distal opening 221 of the sheath 220 on the device that has captured the thrombus. If the distal tip of the sheath 220 is enlarged or expanded into a funnel shape relative to its initial size, the chance of fragments of the thrombus breaking off or causing embolism is minimized because the larger size or funnel shape of the sheath tip is more likely to accommodate the embolism sucked therein without causing the embolism to be broken into multiple fragments. This produces better clinical results for the patient. In one embodiment of the access sheath, the distal portion of the sheath body 222 is such a material and / or construction that the tip can expand after the sheath 220 is inserted into the artery and positioned at its desired position. In one embodiment, the distal region of the sheath has an ID of approximately 0.087" that can expand to a diameter of approximately 0.100" to 0.120", but may vary in size and / or expand.

[0075] Examples of expansion distal tip configurations include a covered braided tip that can be shortened to expand. Another example of an expansion distal tip configuration is an umbrella or similar configuration that can be opened with mechanical actuation or elastic spring force when unconstrained. Other mechanisms for expandable diameter tubes are well known in the art. A specific embodiment is a sheath made of a material that is deformable when inflated using a high pressure balloon.

[0076] Exemplary devices are described in co-pending U.S. Patent Publication No. 2015 / 0173782, filed on December 19, 2014, and are incorporated herein by reference in their entirety. The construction of such features is described in co-pending Publication No. 2015 / 0173782.

[0077] The distal region of the sheath body 222 may also vary in the location, size, and number of openings. The sheath body 222 may incorporate one or more openings near the distal region of the sheath 220 that allow fluid flow between the lumen 223 of the sheath body 222 and the vascular system in which the sheath 220 is located. The one or more openings may be sized to allow at least the lumen portion 322 of the aspiration catheter 320 to extend therethrough. The one or more openings may be sized to be larger than the outer diameter of the lumen portion 322 such that the one or more openings form an elongated opening, slot, or notch in the distal region of the sheath body 222. The one or more openings may be formed in a sidewall region of the sheath body 222 just near the distal end such that the opening is located at least 0.25 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, or 4.0 mm or more from the distal end of the sheath body 222. The one or more openings can be a plurality of openings forming a porous region near the distal region of the sheath body 222, wherein at least one of the plurality of openings is sized to be large enough to allow one or more components of the system to exit the lumen 223 of the sheath body 222. In some embodiments, the one or more openings include a distal opening 221 from the lumen 223 of the sheath body 222 (see Figure 4 and 12C In some embodiments, the one or more openings include an elongated distal port forming a side opening 1219 on a first side of the sheath body 222 positioned proximal to the distal region (see Fig. 12C). The side opening 1219 can be located at least 0.25 mm or more distal to the sheath body 222. The side opening 1219 can have a diameter at least as large as the outer diameter of the distal lumen portion 322 of the catheter 320 with spine. Preferably, the side opening 1219 has a diameter that is at least 1.5 times, 2 times, 2.5 times, or 3 times as large as the outer diameter of the distal lumen portion 322. In another embodiment, the sheath body 222 includes a pair of side openings 1219 on opposite and / or adjacent sides of the sheath body 222 near the distal region. In another embodiment, the sheath body 222 includes a distal opening 221 from the lumen 223 and one or more elongated side openings 1219 from the lumen 223. It should be appreciated that the sheath body 222 can be rotated about the longitudinal axis A so that the one or more side openings 1219 are positioned to allow the catheter 320 to extend distally from the side openings 1219 in a desired direction relative to the longitudinal axis A of the sheath 220. Including a wide mouth side opening 1219 can allow the catheter 320 to have a range of exit angles from a position approximately (i.e., very nearly) parallel to the sheath body 222 to a position at a certain angle to the sheath body 222 (e.g., approximately perpendicular to the sheath body 222 or at a right angle thereto, and an angle greater than 90°). This arrangement can be critical in situations where there is significant angulation or bifurcation within the vessel being traversed. Typically, tortuous segments and bifurcations in blood vessels have significant angulations of up to 90° or greater angles of up to 180°. Typical significant angulation points in the vascular system can include the aorto-iliac junction, the bifurcation of the left subclavian artery from the aorta, the bifurcation of the brachiocephalic (innominate) artery from the ascending aorta, and many other peripheral locations.

[0078] Reference again Figure 1As described above, the catheter system 300 may include an aspiration catheter 320 with a spine having a flexible distal lumen portion 322 and a rigid proximal spine 330. Compared to other systems configured to navigate through the cardiovascular system, the outer diameter of the distal lumen portion 322 and the flexibility and lubricity of the lumen portion 322 paired with the rigid spine 330 allow the aspiration catheter 320 with a spine to navigate to the occlusion site in the cerebral vascular system. The system described herein can reach the occlusion in areas of the anatomical structure with a long, tortuous access route. The route may contain stenotic plaque material in the aortic arch and the origin of the carotid and brachiocephalic vessels, creating a risk of embolic complications. In addition, cerebral vessels are generally more fragile and prone to perforation than coronary arteries or other peripheral vascular systems. Because it can overcome these access challenges, the catheter system described herein can more easily provide neurovascular interventional procedures. The catheter system described herein is designed to navigate through tortuosity rather than push through it. U.S. Patent Publication No. 2015 / 0174368, filed December 12, 2014, and U.S. Patent Publication No. 2015 / 0173782, filed December 19, 2014, which are incorporated herein by reference, describe features of catheter devices that can navigate through the tortuous anatomy of cerebral arteries.

[0079] The length of the distal lumen portion 322 can vary. In some embodiments, the length of the distal lumen portion 322 extends from an area near the distal tip of the access sheath body 222 to the occlusion site in the carotid artery, forming a proximal overlap region 120 with the distal end of the access sheath 220 (see Figure 2B ). Taking into account the variation in the occlusion site and the location where the distal tip of the access sheath may be positioned, the length of the distal lumen portion 322 may be in the range of about 10 cm to about 25 cm. The length of the distal lumen portion 322 is less than the length of the sheath body 222 of the access sheath 220 so that when the spine-carrying aspiration catheter 320 is retracted into the sheath body 222, a seal is maintained between the overlap region 328 of the spine-carrying aspiration catheter 320 and the inner diameter of the sheath body 222.

[0080] The catheter systems described herein can incorporate multiple spine-bearing catheters nested within one another to allow extension to tortuous anatomical structures. For example, a first spine-bearing catheter 320 having an outer diameter sized to be received within the lumen of the sheath body 222 can have a second spine-bearing catheter 320 extending through the inner lumen of the first spine-bearing catheter 320. The second spine-bearing catheter 320 can extend beyond the distal end of the first spine-bearing catheter 320 using its proximal spine, so that the smaller diameter second spine-bearing catheter 320 can reach more distal areas of the vascular system, particularly distal areas with narrower dimensions. In this embodiment, the first spine-bearing catheter 320 can be used as a support catheter for the second spine-bearing catheter 320. The second spine-bearing catheter 320 can have an inner lumen that is fluidly connected to the inner lumen of the first spine-bearing catheter 320, and the inner lumen of the first spine-bearing catheter is fluidly connected to the inner lumen of the sheath body 222 to form a continuous suction lumen.

[0081] In one embodiment, the distal lumen portion 322 of the catheter 320 is constructed to be flexible and lubricated so as to enable safe navigation to the target site, and to resist kinking and collapse when subjected to high suction forces so as to effectively aspirate clots, with a portion of increased flexibility toward the distal end. In one embodiment, the distal lumen portion 322 includes three or more layers, including an inner lubricating liner, a reinforcing layer, and an outer sheath layer. The outer sheath layer can be composed of discontinuous portions of polymers with different hardness, composition and / or thickness to change flexibility along the length of the distal lumen portion 322. In one embodiment, the lubricating inner liner is a PTFE liner with one or more thicknesses along the variable portion of flexibility. In one embodiment, the reinforcing layer is a generally tubular structure formed by, for example, a wound ribbon or coil or braid. The material used for the reinforcing structure can be stainless steel, such as 304 stainless steel, nitinol, cobalt-chromium alloy, or other metal alloys that provide a desired combination of strength, flexibility and extrusion resistance. In one embodiment, the reinforcing structure includes a variety of materials and / or designs to change flexibility again along the length of the distal lumen portion 322. In one embodiment, the outer surface of the catheter 320 is coated with a lubricating coating, such as a hydrophilic coating. In some embodiments, the coating can be on the inner surface and / or the outer surface to reduce friction during tracking. The coating can include various materials known in the art. The spine portion 330 can also be coated to improve tracking through the passage sheath 220. Suitable lubricating polymers are well known in the art and can include silicones, etc., hydrophilic polymers, such as high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylether oxides, polyvinyl pyrrolidone, polyvinyl alcohol, hydroxyalkyl cellulose, algin, sugars, caprolactone, etc., and mixtures and combinations thereof. Hydrophilic polymers can be blended with each other or with a formulated amount of water-insoluble compounds (including some polymers) to produce a coating with suitable lubricity, adhesion and solubility.

[0082] The outer diameter of the distal lumen portion 322 can be sized for navigation into a cerebral artery. It is desirable that the catheter have an inner diameter as large as possible that can be safely navigated to the occlusion site in order to optimize aspiration force. Depending on the patient's anatomy and the size and composition of the clot, a suitable size for the inner diameter can be in the range of between 0.040" and 0.075", or can be in the range of between 0.040" and 0.088". The outer diameter should be as small as possible while still maintaining the mechanical integrity of the catheter 320. However, at the overlap region 120, the outer diameter (OD) of the catheter 320 approaches the inner diameter (ID) of the access sheath 220, thereby forming a sealing area at the overlap region 120 while still enabling the catheter 320 to be easily inserted through the sheath 220 and positioned at the desired site. In one embodiment, the catheter 320 and the access sheath 220 are sized to match at the overlap region 120 without a change in the outer diameter of the catheter 320 (see Figure 2B ). In one embodiment, the difference between the access sheath ID and the catheter OD in the overlap region is 0.002" or less. In another embodiment, the difference is 0.003" or less. In one embodiment, the catheter 320 tapers toward the distal tip of the distal lumen portion 322 such that the distal-most end of the catheter has a smaller outer diameter than a more proximal region of the catheter where the catheter seals to the access sheath. In another embodiment, the catheter OD is incremented at the overlap portion 328 to more closely match the sheath inner diameter (see Figure 1 ). This embodiment is particularly useful in systems having more than one catheter adapted for a single access sheath size. It should be appreciated that where the catheter OD of the spine-bearing catheter 320 matches or differs by 0.002" or less from the sheath inner diameter, sealing of the fluid being injected or aspirated can be achieved by the overlap 328, such that there is no need to increase the catheter OD. Sealing of the fluid being injected or aspirated between the catheter and the sheath can be achieved by their substantially similarly sized overlap without incorporating any separate sealing structure or sealing feature.

[0083] In such Fig. 8A and 8B In another embodiment shown, there is a sealing element 336 located on the outer surface of the proximal end of the distal lumen portion 322. The sealing element 336 can be one or more external ridge features and can be compressed when the catheter 320 is inserted into the lumen of the access sheath 220. The geometry of the ridges can allow the sealing element 336 to function as an O-ring, quad ring, or other piston seal design. Figure 8BA similar configuration is shown, where the sealing element 336 has a wiper seal configuration, such as an inclined surface biased against the inner surface of the access sheath body 222. Alternatively, the sealing element 336 can be an inflatable or expandable member, such as a balloon or a covered braided structure, which can be inflated or expanded and provide a seal between the two devices at any time including after the catheter 320 is positioned at the desired site. An advantage of this embodiment is that no sealing force is applied to the catheter 320 during catheter positioning, but rather the sealing force is applied or actuated to seal after the catheter 320 is positioned.

[0084] It should be understood that Figures 8A-8B 322. The shape of the proximal region of the distal lumen portion 322 can have an angled cut compared to the straight cut shown in . It should also be appreciated that the spine 330 can be coupled to the proximal region of the catheter 320 and / or can extend along at least a portion of the distal lumen portion 322 so that the spine 330 is coupled to the distal lumen portion 322 at a distance from the proximal end. The spine 330 can be coupled to the portion 322 by various mechanisms, including bonding, welding, gluing, clamping, stringing, tying, or tying one or more components that make up the spine 330 and / or portion 322. In some embodiments, the spine 330 and the lumen portion 322 are coupled together by clamping the spine 330 between the layers of the distal lumen portion 322. For example, the spine 330 can be a hypotube or rod having a distal end that is cut, ground, or cut so that the distal end can be laminated or otherwise attached to the layers of the catheter portion 322 near the proximal region. The overlap area between the distal end of spine 330 and portion 322 may be at least about 1 cm. This type of coupling allows for a smooth and even transition from spine 330 to lumen portion 322.

[0085] In one embodiment, the overlap region is configured to enable sealing of a vacuum of up to 25 inHg or up to 28 inHg. In one embodiment, the overlap region 120 is configured to enable sealing of pressures of up to 300 mmHg or up to 600 mmHg or up to 700 mmHg without substantial leakage. Additionally, there may be features that prevent over-advancement of the spine-bearing aspiration catheter 320 beyond the distal end of the access sheath 220. In any embodiments involving an increasing diameter or protruding feature at the overlap region 328 of the spine-bearing aspiration catheter 320, the access sheath body 222 may include an undercut at the tip that prevents the proximal overlapping portion of the spine-bearing aspiration catheter 320 from leaving the sheath body 222.

[0086] The distal lumen portion 322 of the catheter 320 may have a radiopaque marker 324 at the distal tip to aid in navigation and proper positioning of the tip under fluoroscopy (see Figure 1). In addition, the proximal overlap region 328 of the catheter 320 may have one or more proximal radiopaque markers 1324 (see Fig. 12C ) so that the overlap region 120 can be visualized as the relationship between the access sheath distal marker 224 and the catheter proximal marker 1324. In one embodiment, the two markers (the marker 324 at the distal tip and the more proximal marker 1324) are distinct to minimize confusion in the fluoroscopic image, e.g., the catheter proximal marker 1324 can be a single band and the sheath tip marker 224 can be a double band.

[0087] The spine 330 of the spine-carrying aspiration catheter 320 is coupled to the proximal region of the distal lumen portion 322. The spine 330 is configured to allow the catheter 320 to be distally advanced and proximally retracted through the lumen 223 of the access sheath 220. In one embodiment, the length of the spine 330 is longer than the entire length of the access sheath 220 (from the distal tip to the proximal valve), for example, about 5 cm to 15 cm in length. Figure 1 As shown in , the spine 330 may include a mark 332 to indicate the overlap between the distal lumen portion 322 of the catheter 320 and the sheath body 222. The mark 332 can be positioned so that when the mark 332 is aligned with the sheath proximal valve 234 during the insertion of the catheter 320 through the sheath 220, the suction catheter 320 with the spine is positioned at the most distal position, where the overlap length required to create a seal between the suction catheter 320 with the spine and the access sheath 220 is minimal. The spine 330 may include a gripping feature, such as a tab 334 on the proximal end, to make the spine easy to grasp and advance or retract. The tab 334 can be coupled to one or more other components of the system 300, such as a dilator configured to extend through the lumen 323 of the distal lumen portion 322, which will be described in more detail below. The proximal tab 334 can be designed to be easily identifiable from other devices (e.g., a guidewire 270 or a retrievable stent device wire 500) present in the sheath proximal valve 234. In one embodiment, spine 330 is colored or marked with a bright color so that it can be easily distinguished from a guidewire, a retrievable stent tether, or the like.

[0088] The spine 330 can be configured to have sufficient rigidity to allow advancement and retraction of the distal lumen portion 322 of the aspiration catheter 320 with the spine, but also have sufficient flexibility to navigate through the brain anatomical structure as needed. In addition, the outer diameter size of the spine 330 is determined to avoid occupying too much lumen area in the lumen 223 of the sheath body 222 and the access sheath 220. In one embodiment, the spine 330 is a round wire with a size from 0.014" to 0.018". In another embodiment, the spine 330 is a ribbon with a size range from 0.010" to 0.015" thickness, and 0.015" to 0.025" thickness. The ribbon can have a variety of cross-sectional shapes, such as a flat ribbon or a curved ribbon forming a c-shape or other shape along an arc. In another embodiment, the spine 330 is a hypotube. In one embodiment, the material of the spine 330 is a metal such as stainless steel or nitinol, and a plastic such as any of a variety of polymers.

[0089] One or more components of the systems described herein can be made of metals, metal alloys, polymers, metal-polymer composites, ceramics, combinations thereof, or the like, or other suitable materials. Some examples of suitable metals and metal alloys include stainless steels, such as 304V, 304L, and 316LV stainless steels; mild steels; nickel-titanium alloys, such as linear elastic and / or superelastic nitinol; other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625, such as 625, UNS: N06022, such as UNS: N10276, as other alloys, etc.), nickel-copper alloys (e.g., UNS: N04400, 400, 400, 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035, such as etc.), nickel-molybdenum alloys (e.g., UNS: N10665, ALLOY ), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, etc.; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (for example, UNS: R30003, such as etc.); platinum-rich stainless steel; titanium; combinations thereof; etc.; or any other suitable material.

[0090] The connection between the distal lumen portion 322 of the catheter 320 and the proximal spine 330 can be configured to allow a smooth transition in flexibility between the two portions without creating kinks or weak points, and also to allow devices such as guidewires and microcatheters to pass smoothly through the continuous inner lumen created by the lumen 223 of the access sheath 220 and the lumen 323 of the lumen portion 322 of the catheter 320. In one embodiment, the distal lumen portion 322 has a transition portion 326 (see Figure 1 ), near the transition portion, portion 322 is connected to the spine 330 with an angled cut so that there is no steep step transition from the inner lumen 223 of the sheath 220 to the inner lumen 323 of the catheter 320. The angled cut can be generally planar. In alternative embodiments, the angled cut is curved or stepped to provide a more gradual transition area. The distal lumen portion 322 and the spine 330 can be connected by welding, mechanical bonding, adhesive bonding, or some combination thereof. The distal end of the spine 330 can have features that promote mechanical bonding during welding, such as a textured surface, protruding features, or cut-out features. These features will facilitate the mechanical bonding between the polymer distal lumen portion 322 and the spine 330 during the thermal welding process. In another embodiment, for example Figures 12A-12B The catheter system 1300 shown in FIG. 1 has a spine catheter 1320 and a dilator 1340 extending therethrough, forming a smooth transition of flexibility between the two portions so as not to kink or create a weak point during advancement of the system 1300. Loss of this smooth transition of flexibility may occur when the dilator 1340 is removed from the spine catheter 1320. The spine 1330 may be used primarily to retrieve the spine catheter 1320, wherein the risk of kinking or weak point formation is significantly lower.

[0091] The spine-supported aspiration catheter 320 does not have a lumen extending throughout its entire length 320 due to the presence of the spine 330 on its proximal region, so if the lumen of the catheter becomes blocked, either prior to use or during a procedure, conventional flushing and priming procedures are ineffective. In conventional single lumen catheters, a syringe is attached to the proximal adapter of the catheter and the inner lumen can be vigorously flushed with a solution. The spine-supported catheter 320 can be provided with an auxiliary catheter flushing and clearing device 350 (see Figure 1). The device 350 can be a tube with a rounded or tapered tip on the distal end and a female luer connection on the proximal end. The luer connector allows a syringe to be connected to the device 350. The blunt or tapered tip enables the device 350 to be inserted into the distal or proximal end of the lumen portion 322 of the catheter 320 without the risk of damaging the catheter 320, and the syringe is actuated to flush the device. The OD of the cleaning device 350 closely matches the ID of the lumen portion 322 of the catheter 320 with a spine, so that the suction catheter 320 with a spine can be flushed with sufficient force to remove debris and aspirated occlusive materials from the catheter. The device 350 can also be used to mechanically remove any entrained thrombus with a plunger-like action, and the working length of the device 350 can be at least as long as the distal lumen portion 322 of the catheter 320, so that it can be inserted through the entire lumen 323 of the distal lumen portion 322. Flushing may occur in conjunction with inserting the device 350 to more effectively clear entrained thrombus or other embolic material from the catheter 320 .

[0092] In an alternative embodiment, the aspiration catheter 320 is a single lumen catheter, for example, a catheter of the type described in co-pending U.S. Patent Publication No. 2015 / 0174368 filed on December 12, 2014. In such an embodiment, the catheter can be equipped with or coupled with a tapered coaxial dilator 340 that is generally tubular and has a tapered distal portion that provides a smooth transition between the catheter and a guidewire positioned within the catheter.

[0093] The spine-mounted aspiration catheter 320 can be navigated through the vascular system over a microcatheter and guidewire of appropriate size. Alternatively, the spine-mounted catheter 320 can be equipped with a coaxial dilator 340 (see Figure 1 ). The dilator 340 is sized and shaped to be inserted through the inner lumen 323 of the distal lumen portion 322 of the catheter 320 in a coaxial manner so that the proximal region of the dilator 340 is aligned side by side with the spine 330 of the catheter 320 when in use. The dilator 340 can have a tapered distal tip 346. The length of the dilator 340 can be at least as long as the aspiration catheter 320 with the spine to allow the distal tapered tip 346 to protrude at least from the distal end of the lumen portion 322 of the catheter 320 with the spine. The dilator 340 can have an outer diameter that forms a smooth transition to the distal tip of the catheter, and a distal tapered tip 346 that provides a smooth transition down to a guidewire that extends outside the inner lumen of the dilator 340. The dilator 340 can be generally tubular along at least a portion of its length. In one embodiment, the tapered dilator 340 is designed to accommodate a guidewire that can be, for example, in the range of 0.014" to 0.018". In this embodiment, the inner lumen diameter may be between 0.020" and 0.024". The tapered distal tip 346 may be in the range of 1.5 cm to 3 cm.

[0094] It should be appreciated that the dilator described herein for use with a catheter with a spine can vary in its configuration. For example, as described above, the dilator 340 can be a coaxial dilator 340 that is generally tubular and has a tapered distal portion that provides a smooth transition between the catheter 320 and the guidewire positioned within the catheter 320. The tubular body of the dilator 340 can extend along the entire length of the catheter 320. Alternatively, the dilator 340 can incorporate a proximal spine that is aligned side by side with the spine of the catheter 320. The proximal spine can be coaxially or eccentrically positioned with the distal region of the dilator 340. The coaxial proximal spine of the dilator 340 can have a lumen extending through it. Alternatively, the dilator 340 can be a solid rod without a lumen. The solid rod dilator can be formed of a ductile material that can be thinned to have a narrow outer diameter (e.g., 0.010"-0.014") so that the dilator can be shaped into any angle or shape desired by the user, similar to how a guidewire can be used. In this configuration, the catheter system does not include a guidewire or microcatheter.Such a dilator has advantages over a microcatheter in that it can have an outer diameter that is 0.003"-0.010" smaller than the inner diameter of the spine catheter 320.

[0095] The dilator 340 can have a proximal female luer adapter 348 at the proximal end to allow the dilator 340 to be flushed with a syringe. The dilator 340 can also incorporate a clip feature at the proximal end to allow the dilator 340 to make the material of the dilator 340 sufficiently flexible and the tapered distal tip 346 can be long enough to create a smooth transition between the flexibility of the guidewire and the flexibility of the catheter. This configuration can facilitate the advancement of the catheter 320 into the target cerebral vascular system through curved anatomical structures. In one embodiment, the distal end of the dilator 340 has a radiopaque marker 344 and / or a marker 343 at the proximal end of the tapered distal tip 346. The marker material can be a platinum / iridium band, tungsten, platinum, or tantalum impregnated polymer, or other radiopaque markers.

[0096] The dilator 340 can be configured to have a variable stiffness between the distal and proximal ends of the dilator 340. For example, the distal-most portion extending beyond the distal end of the lumen portion 322 of the catheter 320 can be made of a more flexible material, with the material stiffness increasing toward the more proximal portions. In some embodiments, the dilator 340 can be a spine-bearing dilator having a proximal spine, which will be described in more detail below. The proximal end of the dilator 340 may include a tab 1364 that allows the dilator 340 to lock with a tab 334 on the proximal end of the spine 330 of the catheter 320 so that the two components (the spine-bearing catheter 320 and the dilator 340) can be advanced over the guidewire as a single unit (see Fig. 12A). In some embodiments, the tab 334 of the catheter 320 can form a ring with a central opening extending therethrough. The tab 1364 of the dilator 340 can have an annular detent with a central post. The central post of the tab 1364 can be sized to be inserted through the central opening of the tab 334 so that the ring of the tab 334 is received within the annular detent of the tab 1364, forming a single gripping element for the user to advance and / or withdraw the catheter system through the access sheath. The tab 1364 can be fixed to the dilator 340, or can be slidable on the dilator 340 to accommodate different relative positions between the dilator 340 and the catheter 320 with spine.

[0097] Figure 12A-16 Additional views of an aspiration catheter and dilator system 1300 with spine as described elsewhere herein are provided. Figures 12A-12B The aspiration catheter 1320 with spine is shown having a dilator 1340 extending through the aspiration lumen 1323 of the distal lumen portion 1322. As described elsewhere herein, the catheter 1320 can include a proximal spine 1330 having a tab 1334 and a distal lumen portion 1322 having the aspiration lumen 1323. The spine 1330 can extend between the distal lumen portion 1322 and the tab 1334. The dilator 1340 can be received within the aspiration lumen 1323 of the catheter 1320 with spine. The dilator 1340 can include a distal dilator portion 1360 and a proximal spine 1362. The dilator portion 1360 can extend between a distal tip 1346 of the dilator 1340 and the beginning of the proximal spine 1362. When engaged with the catheter 1320, the dilator portion 1360 of the dilator 1340 can extend through the entire length of the distal lumen portion 1322 of the catheter 1320, such that the dilator tip 1346 extends a fixed distance beyond the distal end of the distal lumen portion 1322 of the catheter 1320 to provide a smooth transition for improved tracking. The dilator tip 1346 can be tapered, as described elsewhere herein, and can be soft, non-invasive, and flexible to the vessel wall to facilitate intravascular navigation to embolize in tortuous anatomical structures, as compared to dilators typically used for percutaneous arterial access (which are used to bluntly dissect through tissue and arterial walls).

[0098] The dilator 1340 is shown in a locked configuration, wherein the catheter 1320 is configured for improved tracking through the acute ischemic stroke tortuosity and generally diseased vasculature. The dilator portion 1360 may include one or more detents on an outer surface of the dilator portion 1360. The detents may be located near the proximal region and / or distal region of the dilator portion 1360. The detents are configured to lock with correspondingly shaped surface features on the inner surface of the lumen 1323 through which the dilator portion 1360 extends. The dilator 1340 may include a dilator tab 1364 on the proximal end of the proximal spine 1362 of the dilator 1340, as described above, which may be configured to connect and lock with corresponding features on the proximal region of the catheter spine 1330, such as via one or more detents or other surface features. Thus, the dilator 1340 and the catheter 1320 may have more than one locked connection point between them. The proximal spine 1362 of the dilator 1340 can extend between the dilator portion 1360 and the tabs 133 of the dilator 1340. The dilator portion 1360 can be a tubular element as described elsewhere herein that forms a guidewire lumen extending over the length of the dilator portion 1360 (and the entire length of the distal lumen portion 1322 of the catheter 1320 with the spine). It should be appreciated that the entire dilator 1340 can be a tubular element configured to receive a guidewire through the spine 1362 and the dilator portion 1360. The proximal end of the dilator portion 1360 (i.e., the transition portion 1326 between the dilator portion 1360 and the proximal spine 1362) can include a "step-up" to smooth the transition between the distal lumen portion 1322 of the catheter 1320 and the dilator portion 1360 of the dilator 1340. The transition portion 1326 can incorporate an angled cut so that there is no sharp step transition from the inner lumen 1223 of the sheath 1220 to the inner lumen 1323 of the catheter 1320. Thus, the spined aspiration catheter-dilator 1300 can be smooth to the vessel wall it interfaces with.

[0099] The proximal spine 1362 of the dilator 1340 can have similar stiffness and properties as the spine 1330 of the catheter 1320. More particularly, one or both of the spines 1362, 1330 can be rigid and / or kink resistant. In addition, one or both of the spines 1362, 1330 can have stiffness to allow the distal portion (i.e., the combined distal lumen portion 1322 and dilator portion 1360) to be pushed through the access sheath or guide sheath while creating a very low profile. In one embodiment, one or both of the spines 1362, 1330 include a rigid wire.

[0100] The catheter tab 1334 and the dilator tab 1364 can be removably connected to each other. More specifically, the tabs 1334, 1364 can have a locked configuration and an unlocked configuration. In the locked configuration, the dilator tab 1364 can be engaged with the catheter tab 1334. In the unlocked configuration, the dilator tab 1364 can be disengaged from the catheter tab 1334. The dilator tab 1364 can be attached (e.g., snapped or locked) to the catheter tab 1334 in such a manner that it maintains the relationship of the corresponding portions of the spine catheter 1320 and the spine dilator 1340 in the locked configuration. Such locking can be achieved by, for example, using a detent on the dilator tab 1364 that snaps into place within a recess formed in the catheter tab 1334, or vice versa. In some embodiments, the spine 1330 of the spine catheter 1320 can extend beside or within the dedicated channel of the dilator spine 1362. The channel can be positioned along the length of the dilator spine 1362 and have a cross-sectional shape that matches the cross-sectional shape of the catheter spine 1330, so that the spine 1330 of the catheter 1320 can be received within the channel and smoothly slide bi-directionally along the channel. Once the spine-bearing catheter 1320 and the spine-bearing dilator 1340 are secured, the combined system (i.e., the spine-bearing aspiration catheter-dilator 1300) can be delivered to the target site, such as through the lumen 223 of the access sheath 220 described elsewhere herein.

[0101] refer to Fig. 12B , a spine-carrying aspiration catheter-dilator 1300 is shown with a spine-carrying catheter 1320 and a spine-carrying dilator 1340 in an unlocked configuration according to one embodiment. When the spine-carrying aspiration catheter-dilator 1300 is at a target site, as discussed herein, the dilator tab 1364 can be unlocked from the catheter tab 1334. The spine-carrying dilator 1340 can be retracted and the spine-carrying catheter 1320 can be used, for example, for aspiration or for guidewire or balloon delivery.

[0102] refer to Fig.13 , according to one embodiment, a spine-bearing catheter 1320 coaxially aligned with a spine-bearing dilator 1340 is shown along Fig. 12B13. A cross-sectional view taken along line AA of FIG. 13. The cross-section shows a portion of a catheter-dilator in which the dilator portion 1360 is received within the aspiration lumen 1323 of the distal lumen portion 1322. The lumen 1323 can have an inner diameter in the range of up to 0.072 inches, but larger or smaller inner diameters are possible (possibly larger or smaller). The wall of the distal lumen portion 1322 can be kink-resistant or ovalized to provide a maximum diameter for aspiration. The dilator portion 1360 can be received in the distal lumen portion 1322 with a sliding fit. Thus, in one embodiment, the outer dimension of the dilator portion 1360 can be smaller than the inner diameter of the distal lumen portion 1322. For example, the lumen 1323 can have a diameter of 0.072 inches, while the dilator portion 1360 can have an outer dimension of 0.070 inches.

[0103] refer to Fig.14 , according to one embodiment, shows the spine catheter 1320 after the spine dilator 1340 is removed along the Fig. 12B BB. The cross section shows the distal lumen portion 1322 after the dilator portion 1360 has been retracted and / or removed. The distal lumen portion 1322 has an inner wall 1321 defining a lumen 1323. The lumen 1323 can be circular, as shown, or can have any other shape. In one embodiment, the effective diameter of the lumen 1323 is in the range of up to 0.072 inches.

[0104] refer to Fig.15A , a spine-bearing aspiration catheter-dilator system 1300 having a spine-bearing catheter 1320 and a spine-bearing dilator 1340 in a locked configuration is shown according to one embodiment. In one embodiment, the spine 1330 and the dilator 1340 can have substantially similar outer dimensions throughout their length. For example, instead of converging to a smaller dimension between the dilator portion 1360 and the dilator spine 1362, the dilator spine 1362 can have the same dimensions as the dilator portion 1360. Thus, a catheter-dilator having substantially the same cross-sectional area over at least a majority of its length can be provided. As described above, the spine-bearing dilator 1340 and the spine-bearing catheter 1320 can have corresponding tabs 1334, 1364 that engage in the locked configuration and disengage in the unlocked configuration.

[0105] refer to Fig. 15B, a spine-bearing aspiration catheter-dilator having a spine-bearing catheter 1320 and a spine-bearing dilator 1340 in an unlocked configuration is shown according to one embodiment. The spine-bearing dilator 1340 can be removed from the spine-bearing catheter 1320 in a manner similar to that described above. In one embodiment, the spine-bearing aspiration catheter-dilator can have similar cross-sections over a majority of its length, and thus, the shapes of the spine-bearing catheter 1320 and the spine-bearing dilator 1340 can be complementary. For example, the spine 1330 can have a cross-section along an arc, such as a quarter circle, and thus, the cross-section of the dilator spine 1362 can be three quarters of a circle. Thus, the spine 1330 can conform to the dilator spine 1362 to provide an overall cross-section that is a full circle.

[0106] refer to Fig.16 , a schematic diagram of a spine-bearing catheter 1320 located in a neurovascular anatomy is shown according to one embodiment, the spine-bearing catheter including a distal lumen portion 1322 having an inner lumen 1323. Used in conjunction with an access sheath 1220 having a sheath body 1222 and an inner lumen 1232, in embodiments where the spine-bearing catheter 1320 reaches the ICA and the distance to the embolism E is always felt to be less than 20 cm, it can be seen that a distal lumen portion 1322 having a length of 25 cm will allow an overlap region 1120 with the access sheath 1220 to create a seal. The overlap region 1120 can have a length of several centimeters and can vary depending on the distance from the embolism E to the distal end of the distal lumen portion 1322, e.g., depending on how far the spine-bearing catheter 1320 is advanced relative to the access sheath 1220.

[0107] As described elsewhere herein, the lumen area available for aspiration of emboli using a catheter 1320 with a spine is larger than that of an aspiration system with a conventional large-bore catheter in a passage sheath. More particularly, the combined area of ​​the lumen area of ​​the catheter 1320 with a spine and the lumen area of ​​the passage sheath 1220 proximal to the distal lumen portion 1322 is greater than the lumen area of ​​a large-bore catheter along the entire length of the system. Therefore, the possibility of removing an embolism in a single aspiration attempt can be increased. More particularly, the incremental lumen diameter along the spine 1330 can be able to obtain greater aspiration force, resulting in improved aspiration of emboli. When a device such as a microcatheter or a tapered inner member is coaxially positioned in a catheter with a spine and a passage sheath, the incremental lumen diameter can also increase the annular area available for forward flushing of contrast agents, saline or other solutions. Therefore, the ease and ability of performing angiography during device navigation can be improved.

[0108] The disclosed system can be equipped with auxiliary devices specifically configured for use with the system. It should be appreciated that reference to one embodiment of an access sheath system or an aspiration catheter system is not intended to be limiting, and the auxiliary devices described herein can be used with any system having any of the various features or combinations described herein. For example, where an access sheath is described below, it should be appreciated that one or more features of any access sheath or access sheath system described herein can be combined. Similarly, where a catheter with a spine is described below, one or more features of any catheter with a spine or catheter system with a spine described herein can be combined.

[0109] In one embodiment, the system includes a microcatheter 400 (see Figure 1 ). The microcatheter 400 can be configured to be particularly suitable for navigation in cerebral blood vessels. The microcatheter 400 can be used to replace the tapered dilator 340 to help navigate the catheter 320 with the spine to the desired site. Thus, it can include a device at the proximal end to lock the spine 330 to the microcatheter 400, so that the two components (the catheter 320 with the spine and the microcatheter 400) can be advanced on the guidewire as a single unit. In some cases, the microcatheter 400 is advanced in front of the catheter 320 to provide support when the catheter 320 is advanced, or to pass through the occlusion and perform angiography at the far side of the occlusion. In this case, the length of the microcatheter 400 can be about 10 to 20 cm longer than the catheter 320 with the spine. The microcatheter 400 can also be used to deliver a retrievable stent device 500 to the occlusion. In this case, the microcatheter 400 can have an inner diameter suitable for delivering the retrievable stent device 500, for example, in the range of 0.021 "to 0.027" and with a PTFE liner. The microcatheter 400 may be at least about 5-10 cm or at least about 5-20 cm longer than the overall length of the spine catheter 320 to allow the microcatheter 400 to extend beyond the distal end of the aspiration catheter 320 during navigation.

[0110] In one embodiment, the system includes a retrievable stent device 500 having a distal expandable portion 510 that is sized and configured to be delivered through a microcatheter 400, such as Fig. 9 . The retrievable stent device 500 can be used in conjunction with other components of the system to help remove the occlusion. The retrievable stent device 500 can also be used to quickly restore flow to an occluded artery during a thrombus removal procedure. Examples of retrievable stent devices include the Solitaire revascularization device (Medtronic) or the Trevo stent retriever (Stryker).

[0111] In the method of use, the retrievable stent device 500 is used to help introduce a thrombus into the catheter 320 during the aspiration step, or to clear the catheter 320 that may be blocked during the aspiration step. In one embodiment, the retrievable stent device 500 is configured to be particularly suitable for performing these functions. For example, Fig. 10A As shown in FIG, the distal end of the expandable portion 510 of the device 500 has a plurality of struts or elements 520 that come together at the distal tip to close the distal end so that when the device 500 is pulled into the catheter 320 and then through the catheter 320 and out of the distal end, the device allows blood flow through the device but captures thrombus debris. Alternatively, the distal end 520 is a filter element or a balloon element.

[0112] In another example, in Fig. 10B In the present invention, the retrievable stent device 500 includes two or more segments including one or more proximal segments 510a, which are configured to expand in the distal inner lumen of the catheter when one or more distal segments 510b are expanded across the occlusion, as in the prior art retrievable stent devices. Fig. 10C As seen in the drawings, the retrievable stent device 500 has a very long expandable portion 510 so that the proximal portion of the expandable portion can expand in the distal inner lumen of the catheter when the distal portion expands through the occlusion. In all of these embodiments, the proximal end of the expandable portion 510 has minimal structural elements, which will allow the expandable portion to be easily pulled into the lumen of the catheter 320 and out of the access sheath 320, thereby minimizing the obstruction of aspirating thrombi through the device. In these examples, even when a clot is aspirated into the catheter 320, the expandable portion 510 still engages with the clot, and if the catheter 320 is blocked, the device 500 is well positioned to clear the clot when it is pulled back. Once the retrievable stent device 500 has been removed from the lumen portion 322 of the catheter 320, if the site is still partially or completely occluded, additional suction can be applied to the site through the catheter 320. If the catheter 320 is still blocked, this step will not be possible; the catheter must be removed and cleaned outside the patient before being reinserted for additional suction. This configuration of the retrievable stent device 500 may be used with a conventional single lumen aspiration catheter or a spine-equipped aspiration catheter 320 .

[0113] like Figures 10A-10C The embodiment of the device 500 shown in FIG. 5 can be used with known thrombus removal devices and methods to address the problem of catheter occlusion during thrombus aspiration.

[0114] In one embodiment, the system includes a suction source 600, such as Figure 2A or Figure 3As shown in . The suction source 600 can be attached to the suction line 230 on the access sheath 220. Examples of the suction source 600 include a syringe or an active suction pump. The suction source 600 can be connected to a delivery location, such as a container. The container and the suction source 600 can be independent (e.g., a mechanical or electromechanical fluid pump, whose outlet is connected to the blood collection reservoir) or can be combined into a single device (such as a syringe or a syringe pump). Alternatively, the blood collection reservoir is connected to a vacuum source such as a hospital vacuum line or an air vacuum pump, and is therefore both a container and a suction source. A filter and / or a check valve can be connected to the suction source. The pump can be a positive displacement pump, such as a diaphragm or piston pump, a peristaltic pump, a centrifugal pump, or other fluid pump mechanisms known in the art.

[0115] In one embodiment, the suction source is a variable state or multi-state suction source and includes a mechanism for controlling the suction level, for example, by modifying the vacuum level in a vacuum pump, by modifying the power of a motor of a positive displacement, peristaltic or centrifugal pump, or by modifying the syringe withdrawal speed in a syringe or syringe pump. Alternatively, the suction rate can be varied by providing an element with a variable flow resistance, such as a parallel flow path that can be switched between high and low flow resistance paths, a flow orifice or lumen that can be variably opened, or other means of varying the flow resistance. In an example, the suction source is configured to have two suction levels: a high suction level for aspirating thrombotic occlusions when the catheter is in contact with thrombotic material, and a low suction level for use during procedural steps where the risk of causing distal embolism is high (e.g., when a retrievable stent device is expanded to restore flow to a vessel or to pass through a lesion).

[0116] In another example, if Fig.11 As shown in , the suction source 600 also includes a flow sensor 275 that senses the flow in the suction line 230, which is connected to a controller that controls the suction level. The suction source 600 can increase the suction level when the flow rate is slow, and can reduce the suction level when the flow rate increases. In this way, the force is the greatest when the catheter is blocked or partially blocked, but is reduced to a minimum level when there is free flow to ensure the protection of distal embolism but limit the volume of blood sucked. In this way, the system optimizes thrombus suction while limiting the amount of blood sucked. Alternatively, the suction source 600 can include a vacuum gauge. When the flow in the catheter 320 is blocked or restricted, the pump produces a higher vacuum level. In this example, the suction force can be configured to increase when a higher vacuum is detected.

[0117] In yet another suction source embodiment, the suction source 600 provides a cyclic level of suction force, for example, the suction force cycles between a high vacuum level to a lower vacuum level at a set frequency, or cycles from a high vacuum level to no vacuum, or cycles from a high level of vacuum to a pressure source. The cyclic suction mode can provide a hammer-type force on the thrombus and increase the ability to aspirate the thrombus through the catheter. The cyclic suction force can be achieved by a solenoid valve, a programmable pump motor, etc. In one embodiment, cyclic suction is applied by low flow or high vacuum only when a blockage or restricted flow is detected in the suction line, as described above, and at other times, the suction source returns to a low flow level, or is turned off. This configuration can be controlled by the user, or automatically controlled via a feedback loop to the suction source.

[0118] In one embodiment, the system includes a mechanism for passive reverse flow configured to be connected to an aspiration line on the access sheath. For example, the aspiration line is connected to a low pressure site such as a central vein, or an external container set to zero or negative pressure.

[0119] In such Fig.11 In one embodiment shown, the flush line 236 can be connected to a syringe 286 that can hold saline fluid or radiopaque contrast agent via a stopcock 238. In addition, the flush line 236 can be connected to a flush source 288, such as a pressurized saline bag. A valve 292 can control the flow from the flush source 288 to the flush line 236. When the valve 292 is open to the flush line 236, a pressurized fluid source is provided. In one embodiment, the valve 292 is connected to the suction source 600 via a mechanical or electromechanical coupling 295, so that the valve 292 is only opened when the suction source 600 is turned on. Alternatively, the valve 292 is connected to a flow sensor 275 in the suction line 230, so that the valve 292 is opened only when there is flow in the direction toward the suction source 600. In these embodiments, the flow rate of the flush source 288 is configured to flow just enough to keep the proximal extension 240 free of blood, but not too high so that the flow resists the suction flow and limits the suction of thrombus. An advantage of this embodiment is that the proximal extension 240 remains free of blood, and any emboli or air in the proximal extension 240 is clearly visible. This provides feedback to the user when and whether to flush the catheter with saline or contrast via the syringe 286.

[0120] In another embodiment, valve 292 is mechanically or electromechanically coupled to valve 242 that connects sheath body 222 to proximal portion 240 of sheath 220. Coupling 290 can be configured such that valve 292 can only be opened when valve 242 is closed. This feature allows proximal extension 240 to be cleared of blood via a flushing step without the risk of emboli being backwashed through the catheter into the vascular system. Coupling 290 can be configured in one of several ways. For example, coupling 290 can always open valve 238 when valve 242 is closed, or coupling can prevent valve 238 from opening unless valve 242 is closed but not automatically opened.

[0121] In one embodiment, valve 292 is a variable state valve that allows different levels of flushing flow rates. In this example, valve 292 is configured to allow slow flushing when the suction source is at a low setting and allow higher levels of flushing when the suction source is at a high setting. In one embodiment, when valve 242 is closed, the valve allows higher levels of flushing. These configurations allow for continuous removal of debris and / or clear visibility of the proximal portion of the access sheath, and minimize the risk of distal embolism or air entering the vascular system during the steps of the procedure. For example, during the step of removing the distal tip of the catheter from the proximal hemostasis valve 234, any clot captured on the tip of the catheter may be released when the catheter is pulled through the valve, but using continuous flushing, the released embolism will be flushed into the suction line and not retained in the sheath (where it may be reinjected into the vascular system, such as during contrast injection after the catheter is removed).

[0122] Reference again Figure 1 , the system 100 may include a kit of multiple devices. In an embodiment, the kit includes an access sheath system 200, wherein the access sheath system includes an access sheath, one or more tapered sheath dilators, and one or more sheath guidewires. In another embodiment, the system 100 includes the access sheath system 200 and one or more spine-bearing catheter systems 300 having one or more inner diameters. In one embodiment, the spine-bearing catheter system 300 includes a spine-bearing aspiration catheter 320 and a tapered dilator 340. In one embodiment, the spine-bearing catheter system 300 also includes a catheter cleaning tool 350. In yet another embodiment, the system 100 includes the access sheath system 200, the tapered catheter system 300, the microcatheter 400, and a retrievable stent device 500.

[0123] In an embodiment configured for a transcervical approach, the kit includes an access sheath 220, wherein the length of the insertable sheath body 222 is approximately 23 cm, the proximal extension 240 is approximately 22 cm, the connector 226 is approximately 7 cm, and the proximal hemostasis valve 234 is approximately 5 cm for an overall access sheath length of approximately 57 cm. In one embodiment, the kit also includes an aspiration catheter 320 with a spine, wherein the catheter distal lumen portion 322 is approximately 20 cm, the transition portion 326 is approximately 2-4 cm, and the spine portion 330 is approximately 65 cm for an overall catheter length with a spine of approximately 88 cm. In another embodiment, the kit also includes a tapered dilator 340 having a working length of 93 cm. In another embodiment, the kit also includes a microcatheter 400 having a working length of approximately 198 cm and a retrievable stent device 500 having a total length of 128 cm.

[0124] In an embodiment configured for a transfemoral approach, the kit includes an access sheath system 220, wherein the length of the insertable sheath body 222 is about 90 cm, the proximal extension 240 is about 22 cm, the connector 226 is about 7 cm, and the proximal hemostasis valve 234 is about 5 cm for a total access sheath length of about 124 cm. The proximal portion of the access sheath can be a removable proximal portion 280. In one embodiment, the kit also includes an aspiration catheter 320 with a spine, wherein the catheter distal lumen portion 322 is about 20 cm, the transition portion 326 is about 2-4 cm, and the spine portion 330 is about 132 cm for a total catheter length with a spine of about 155 cm. In another embodiment, the kit also includes a tapered dilator 340 having a working length of 160 cm. In another embodiment, the kit also includes a microcatheter 400 having a working length of about 165 cm and a retrievable stent device 500 having a total length of 195 cm.

[0125] In another embodiment, the kit includes an access sheath 220 with a removable proximal portion 280, and a single lumen aspiration catheter. In another embodiment, the kit includes only the proximal portion 280 that can be attached to any introducer sheath suitable for the procedure. In this embodiment, the kit may also include an aspiration catheter 320 with a spine or a single lumen aspiration catheter.

[0126] In any of these embodiments, the kit may also include a suction source, such as a pump, an attachment to a vacuum pump, a syringe, a syringe attachable to a syringe pump, etc. The kit may also include a device for automatic flushing, such as coupling device 290 or 292.

[0127] As described elsewhere herein, it should be appreciated that reference to one embodiment of an access sheath system or catheter system is not intended to be limiting, and the kits described herein may be combined with any system and / or ancillary device described herein having any of the various features described herein. For example, where an access sheath is described as part of a kit, it should be appreciated that one or more features of any access sheath or access sheath system described herein may be combined. Similarly, where a catheter with a spine is described as part of a kit, one or more features of any catheter with a spine or catheter system with a spine described herein may be combined.

[0128] Figure 2A and 3 The method of use is shown. Figure 2A As shown in , the access sheath 220 is inserted into the femoral artery using a standard vascular access sheath and advanced until the sheath tip is positioned in a safe location as distally as possible in the internal carotid artery or the common carotid artery. Figure 3 In the embodiment of the present invention, the access sheath 220 is inserted directly into the common carotid artery and advanced until the tip of the sheath is positioned in a safe position as distally as possible in the internal carotid artery. In either case, the sheath can be initially advanced to the common carotid artery or the proximal internal carotid artery, and then the dilator is replaced with a softer dilator before the sheath is advanced more distally into the internal carotid artery. The sheath is then secured to the patient using sutures passed through the eyelets on the sheath connector. The sheath aspiration line 230 is connected to a suction source 600 such as a syringe or a suction pump. The sheath aspiration line can also be connected to a forward flush line (e.g., a pressurized saline bag) via a stopcock or a stopcock manifold.

[0129] Once the sheath tip is positioned at the desired location, it is secured to the patient. The catheter with spine, tapered dilator and guidewire are preassembled in a coaxial configuration and introduced into the carotid artery through the proximal hemostasis valve of the sheath. The suction catheter 320 with spine is advanced through the access sheath and positioned until the distal tip is at the treatment site. The device is advanced using standard interventional techniques until the distal catheter tip is at the proximal side of the occlusion. The marking 332 on the spine 330 ensures that there is still an overlap area 120 between the distal lumen portion 322 of the catheter and the access sheath body 222. At this point, the tapered dilator 340 and guidewire can be removed. In an alternative embodiment, a microcatheter 400 is used instead of the tapered dilator 340 to help navigate the catheter 320 to the occlusion. During the procedure, a forward flush is opened to the suction lumen before or between the periods of suction to keep the lumen clean. At any time during device navigation, such as when the guidewire or microcatheter 400 is being passed through an occlusion, suction may be initiated from the suction source 600 at a level suitable for distal embolic protection.

[0130] Once the distal tip of the spine-carrying aspiration catheter 320 is at the face of the clot, aspiration is initiated at a level suitable for aspiration thrombus removal, which is a higher level than distal embolic protection. The catheter 320 can be held in aspiration mode against the clot for a period of time deemed appropriate by the user. Depending on the results of the aspiration thrombus removal operation (obtained by observing the flow through the aspiration line and / or the resistance of the backward force on the spine of the catheter), the user can determine that the clot has been completely aspirated, or if not, the user can choose to move the catheter 320 back and forth to aspirate the clot in place, or slowly retract the catheter 320 into the sheath 220. If flow to the artery is restored by aspirating the clot through the catheter 320 and the sheath 220, a final angiogram can be performed and the catheter 320 can be retracted. However, if the thrombus blocks the catheter tip and cannot be removed, the catheter 320 is pulled back, with some or all of the occlusion attached to the tip of the catheter 320 by the aspiration force.

[0131] In the latter case, suction is maintained at the tip of the catheter 320 the entire time the catheter 320 is pulled into the access sheath 220. Once the catheter 320 has been fully retracted into the access sheath 220, the catheter 320 can be quickly removed from the sheath body 222 while suction is maintained on the sheath 220. It should be appreciated that the catheter 320 can be retracted into the sheath body 222 after extending through the distal opening 219 at the distal tip of the sheath body 222. Alternatively, the catheter 320 can extend through a side opening 219 near the distal region of the sheath body 222 such that retraction of the catheter 320 into the sheath body 220 occurs through the side opening 219. At some time during catheter retraction, the level of suction can be changed from a high level desired for aspiration thrombus removal to a lower level desired for distal embolic protection, depending on whether the catheter 320 is clogged with occlusive material. By providing the ability to continuously maintain suction from the catheter tip or sheath tip or a region distal to the sheath, and providing a means to vary the level of suction and maintain suction, the procedure optimizes the ability to aspirate clots while minimizing distal embolism and minimizing blood loss from the aspiration. If desired, suction may also be initiated at the flush line 236 of the proximal valve 234 to reduce the chance of distal embolism during removal of the catheter tip through the proximal valve 234 where a clot may be adhered.

[0132] The spine-carrying aspiration catheter 320 can be completely removed from the proximal hemostasis valve 234 of the sheath 220. Alternatively, if the access sheath 220 has a proximal extension 240, the distal lumen portion 322 can be pulled into the proximal extension 240. In the latter case, once pulled in, the catheter 320 and sheath 220 can be flushed to remove potential embolic material without completely removing the catheter 320 from the sheath 220. Strong flushing from the proximal valve flush line 236 while aspirating from the aspiration line 230 creates a flushing environment for the catheter 320 and sheath 220. If necessary, the catheter cleaning tool 350 can be inserted into the sheath proximal valve 234 and used to clean the inner lumen 323 of the catheter 320 at this time. If the access sheath 220 has a connector valve 242, the proximal portion 240 can be closed from the sheath body 222 during this stage so that there is no risk of flushing embolic material into the sheath body 222 and then into the artery.

[0133] Alternatively, valve 242 can be closed and suction is paused, while proximal valve 242 is opened or removed and catheter 320 is completely removed from sheath 220. When catheter 320 is removed, closing valve 242 limits blood loss from sheath 220. Cleaning tool 350 can then be used to flush catheter 320 onto a table or into a bowl or other container. Proximal extension 240 can also be flushed by providing a flushing source 288 from proximal valve flushing line 236 simultaneously with flushing from aspiration line 230, or by opening a side port on aspiration line 230 to flush onto a table or into a bowl or other container. If necessary, angiography can be performed to assess flow through the treated artery. If the procedure dictates, catheter 320 or another catheter can be re-advanced to the occlusion site over a guidewire and tapered dilator 340 or microcatheter 400 as described above to attempt another aspiration thrombectomy step. Flushing of the proximal extension 240 of the catheter and access sheath 220 minimizes the risk of distal embolism during these subsequent steps.

[0134] In another exemplary method, the retrievable stent device 500 may be used in conjunction with aspiration to remove thrombotic occlusions. Fig. 9 This method of use is shown through a transcervical or transfemoral access site. In this case, the access sheath 220 can be positioned as above and advanced until the sheath tip is positioned in a safe position as distally as possible in the internal carotid artery. The spine catheter 320 can then be preloaded onto the microcatheter 400 and guidewire, and the coaxial assembly can be introduced into the carotid artery and advanced into the cerebral vessels via the access sheath 220. The microcatheter 400 and guidewire can be advanced through the occlusion. The tip of the spine aspiration catheter 320 can be advanced as distally as possible, but proximal to the clot.

[0135] At this time, the guidewire can be removed and the retrievable stent device 500 can be inserted through the microcatheter 400 until it is also positioned through the occlusion. The microcatheter 400 can be pulled back to deploy the stent. At any time during the device navigation, such as when the guidewire or microcatheter 400 passes through the occlusion or before the stent is deployed, suction can be started from the suction source at a level suitable for distal embolic protection. By starting suction before the stent is deployed, any embolism released when passing through the lesion will not be carried downstream when the flow in the artery is restored, but will be captured in the catheter tip. When the retrievable stent device 500 is deployed, suction can be maintained. It is usually deployed for several minutes before attempting to retract the stent to maximize the engagement of the stent strut with the occlusion. Then, the retrievable stent device 500 can be pulled into the catheter 320 with a spine, and continue to retract until it has been completely removed from the proximal valve of the access sheath 220.

[0136] Alternatively, the stent device 500 can be pulled into the distal portion of the spine catheter 320, and the stent device 500 and spine catheter 320 can be pulled back out of the access sheath 220 together. Suction can be increased to a higher level during the stent and / or catheter retraction step to optimize the aspiration of the clot and minimize distal embolism. If the access sheath 220 has a proximal extension 240 with a valve on the connector, the device 500 can be pulled into the proximal extension 240 and the valve closed, and then the proximal hemostasis valve 234 can be opened widely, and the stent device 500 or stent device / spine catheter combination can be pulled out. Then if the procedure dictates, the proximal extension 240 can be flushed via the valve flush line 236 and the suction line 230 before the same or alternative device is reinserted for another thrombus removal attempt.

[0137] Alternatively, after placing the suction catheter 320, the long or segmented stent retriever 500 can be positioned as above with the microcatheter 400 so that a portion of the expandable portion 510 passes through the thrombus and a portion is in the distal segment 322 of the catheter 320, and then expands. After the expandable portion 510 expands, suction can be started so that the thrombus is completely withdrawn from the blood vessel and the catheter 320 into the suction source 600, or is withdrawn into the distal tip and / or distal lumen 323 of the catheter 320. At this time, the long or segmented stent retriever 500 can be carefully pulled into the catheter 320 while maintaining suction. During this period, the clot that has blocked the catheter 320 and / or the debris released during this step should be sucked into the catheter 320. Completely removing the stent retrieval device 500 from the working channel 323 of the catheter 320 should release the occlusive material from the lumen 323.

[0138] In any of these cases, the suction source can be a variable or multi-state suction source configured to maximize the suction force on the thrombotic occlusion while minimizing blood loss during free flow periods in the catheter.

[0139] In another exemplary method, the access sheath 220 has an occlusion balloon 246. Figure 7 As seen in FIG. 1 , during a procedural step where the risk of distal embolism is high (e.g., retracting a stent device 500 or a spine catheter 320 with an adherent clot), the balloon 246 can be inflated. The balloon 246 has the effect of stopping antegrade flow and increasing suction forces in the carotid artery, thereby increasing aspiration of the clot and reducing the risk of distal embolism.

[0140] In another exemplary method, the access sheath 220 has an expandable distal tip. In this method, the distal tip can be expanded at some time after the access sheath tip has been positioned at the desired site but before the spine catheter 320 is retracted into the access sheath 220. This method will reduce the chance of distal embolism caused by the release of a clot that adheres to the distal tip of the spine catheter 320 as the distal tip is pulled into the tip of the sheath 220. Instead, the expanded or expanded access sheath tip acts as a funnel to capture the entire clot.

[0141] In another exemplary approach and as briefly described above, the access sheath 1220 has a side opening 1219 (at Fig. 12C1219 ). In the method, a spine-bearing catheter 1320 having a spine-bearing dilator 1340 extending through a lumen 1323 of a distal lumen portion 1322 of the catheter 1320 can be advanced distally through the lumen 1223 of the catheter sheath 1220 toward a distal region of the sheath body 1222. The distal tip of the distal lumen portion 1322 of the spine-bearing catheter 1320 (which can have a spine-bearing dilator extending through the distal lumen portion 1322 and forming the most distal end of the catheter system) can exit the lumen 1223 via the side opening 1219 and then be further advanced distally beyond the distal tip of the access sheath 1220. A bevel feature 1217 or other internal feature may be incorporated at the distal region of the lumen 1223 to provide a surface against which the tip of the dilator may be deflected to guide the catheter 1320 toward the side opening 1219 away from the longitudinal axis A of the lumen 1223 of the sheath body 1222 to achieve a smooth transition or exit from the lumen 1223. The distal tip 1346 of the dilator 1340 may abut the bevel feature 1217 and be guided at a slight angle toward the side opening 1219 away from the longitudinal axis of the sheath body 1222. As described elsewhere herein, the sheath body 1222 and thus the side openings 1219 may be rotated about the longitudinal axis A so that one or more side openings 1219 are positioned to allow the catheter 1320 to extend distally from the side opening 1219 in a desired direction relative to the longitudinal axis A of the sheath 1220. This will generally be dictated by the anatomy encountered by the operator. As also described elsewhere herein, an overlap region 1120 is formed between the distal lumen portion 1322 of the catheter and the access sheath body 1222. A sealing element 1336 can be positioned on an outer surface of the distal lumen portion 1322, such as near a proximal region of the distal lumen portion 1322 and can be located within the overlap region 1120. When the dilator 1340 is withdrawn from the lumen 1323 of the lumen portion 1322, the seal formed can allow complete transmission of the suction force through the continuous lumen formed by the lumen 1323 of the lumen portion 1322 and the lumen 1223 of the access sheath body 1222.

[0142] In another exemplary method, the suction source 600 is connected to a blood reservoir that maintains the integrity of the blood in such a way that the blood can be safely returned to the patient at the end of the thrombus removal portion of the procedure, either directly or through subsequent blood processing (such as cell washing and / or blood filtration). In another exemplary method, the suction source is connected to a blood shunt, which in turn is connected to a device such as a venous sheath or venous return catheter that returns the blood to the patient during the procedure and does not require a blood reservoir. In another exemplary method, the blood is collected in a reservoir and then discarded at the end of the procedure.

[0143] In another exemplary method, the access sheath 1220 is delivered from the femoral insertion site to the right subclavian artery or the left subclavian artery or the external carotid artery, as described elsewhere herein. The access sheath 1220 can be delivered to the carina of a bifurcation between a target vessel having an embolism, such as the internal carotid artery (ICA) and another vessel, such as the external carotid artery (ECA). Once the access sheath 1220 is in place, a working device such as a suction catheter 1320 with a spine can be delivered into the target vessel through the lumen 1223 of the access sheath 1220. The lumen 1223 of the access sheath 1220 and the lumen 1323 of the catheter 1320 are continuous and form an increasing diameter for suction, as described elsewhere herein. The overlap region 1120 is maintained between the catheter 1320 extending distally from the lumen 1223 of the access sheath 1220. It should be appreciated that the catheter 1320 can extend distally from the lumen 1223 of the access sheath 1220 through the opening 1221 at the distal tip of the access sheath 1220 or the side opening 1119 near the distal region of the access sheath 1220. The body 1222 of the access sheath 1220 can be oriented to provide optimal placement of the side opening 1119 relative to the anatomical structure. The overlap region 1120 between the distal lumen portion 1322 of the catheter 1320 and the access sheath body 1222 can create a seal and allow complete transmission of suction forces through the continuous lumen formed by the lumen 1323 of the lumen portion 1322 and the lumen 1223 of the access sheath body 1222, as well as provide a seal for delivering fluids to a target vessel (e.g., injecting angiographic contrast media, saline, one or more drugs, or other materials directly into the neurovascular anatomical structure). By allowing the working lumen 1223 of the access sheath 1220 to provide the majority of the aspiration column, the aspiration catheter 1320 with a spine can generate a more powerful aspiration force. As described elsewhere herein, the lumen 1323 of the distal lumen portion 1322 of the aspiration catheter 1320 can be sized smaller than the diameter of the lumen 1223 of the access sheath 1220, which only reduces the diameter of the spine 1330 extending therethrough. The increased diameter of the lumen can generate a larger aspiration column than, for example, a large-bore catheter having a similar overall length. The aspiration catheter 1320 with a spine can also be used as a support delivery catheter in situations where the operator wants to reach the petrous carotid artery or other difficult-to-reach landmarks within the cerebral vascular system. More particularly, after the spine-carrying aspiration catheter 1320 is delivered into the target vessel through the working lumen 1223 of the access sheath 1220, auxiliary working devices such as guidewires, microcatheters, stent retrievers, etc. can be delivered through the lumen 1323 to more distal anatomical structures to perform other procedural operations as described elsewhere herein.

[0144] Although this specification contains many details, these should not be interpreted as limitations on the scope of the invention that is claimed or can be claimed, but rather as descriptions of features that are peculiar to a particular embodiment. Certain features described in the context of an independent embodiment in this specification may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented independently or in any suitable sub-combination in multiple embodiments. Moreover, although the features may be described above as acting in certain combinations and even initially required to be so, one or more features from the required combination may be removed from the combination in some cases, and the required combination may involve a sub-combination or a variation of the sub-combination. Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring such operations to be performed in the particular order shown or in order, or performing all the operations shown to obtain the desired result. Therefore, the essence and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

1. A system for facilitating an intraluminal medical procedure within a neurovascular system, the system comprising: a catheter comprising a distal portion defining a lumen and a proximal spine coupled to the distal portion; An expander, the expander comprising: a flexible elongated body having a tubular body extending along a length between a proximal region and a distal region, the tubular body tapering distally from a first outer diameter to a second outer diameter that is smaller than the first outer diameter, thereby forming a tapered distal tip of the tubular body, a single lumen extending longitudinally through the flexible elongate body to a distal opening at a distal end of the tapered distal tip, wherein the tapered distal tip has at least one radiopaque marker disposed at a proximal end and / or a distal end of the tapered distal tip and identifying the tapered distal tip; and a proximal portion extending from a proximal region of the flexible elongate body, wherein the proximal portion has a lumen and a proximal end configured to be flushed through an adapter at the proximal end, and wherein the tapered distal tip of the tubular body is made of a more flexible material, wherein the material of the tubular body increases in rigidity towards the proximal portion; and a slidable tab adapted to lock a proximal portion of the dilator with a proximal spine of the catheter to adjust a relative position between the dilator and the catheter, wherein, when assembled, at least a portion of the flexible elongated body is positioned within a lumen of the catheter, at least a portion of the tapered distal tip is positioned distal to a distal end of the catheter, and the slidable tab locks with the proximal spine of the catheter to advance the catheter and the dilator together through the neurovascular system, and Wherein, the slidable tab is configured to unlock from the proximal spine of the catheter to withdraw the dilator from the lumen of the catheter.

2. The system according to claim 1, wherein: The proximal portion of the dilator has a single lumen extending through the entire length of the proximal portion and in communication with the single lumen of the flexible elongate body.

3. The system according to claim 1, wherein: The distal region of the dilator is more flexible than the proximal region of the flexible elongate body.

4. The system according to claim 1, wherein: The distal opening of the flexible elongate body is sized to accommodate a guidewire having an outer diameter between 0.014" and 0.018".

5. The system according to claim 1, wherein: The single lumen of the dilator extends the entire length of the dilator, with the inner lumen diameter of the single lumen being between 0.020" and 0.024".

6. The system according to claim 1, wherein: The tapered distal tip of the flexible elongate body extends a length of between 1.5 cm and 3 cm.

7. The system according to claim 1, wherein: The proximal portion of the dilator and the flexible elongate body have substantially similar outer diameters.

8. The system according to claim 1, wherein: A section of the proximal portion of the dilator is configured to be advanced into a blood vessel of a patient, wherein at least a portion of the section comprises a different material than a portion of the flexible elongate body.

9. The system according to claim 1, wherein: The tapered distal tip is made of a polymer.

10. The system according to claim 9, wherein: The flexible material of the tapered distal tip is 35D or 40DPEBAX.

11. The system according to claim 1, wherein: The at least one radiopaque marker is made of a tungsten, platinum, or tantalum impregnated polymer, or is a strip of radiopaque material.

12. The system of claim 1, wherein: The distal portion has a proximal end, a proximal opening, and a distal end, and the lumen of the catheter extends between the proximal end and the distal end, and the lumen of the catheter has an inner diameter between 0.040" and 0.088", wherein the outer diameter of the flexible elongated body is sized to be received within the lumen of the catheter to accommodate different relative positions.

13. The system according to claim 12, wherein: The tapered distal tip has flexibility and a length to create a smooth transition between the flexibility of a guidewire extending through a distal opening of the catheter and the flexibility of the catheter when the tapered distal tip is positioned outside the distal end of the catheter.

14. The system according to claim 12, wherein: The length of the dilator is at least as long as the length of the catheter.

15. The system of claim 12, wherein: The flexible elongate body has a length such that the tapered distal tip extends beyond the distal end of the catheter and the proximal region is located adjacent a proximal opening of a flexible distal lumen portion of the catheter.

16. The system of claim 15, wherein: The length of the distal lumen portion from the distal end to the proximal opening is at least 10 cm.

17. The system of claim 12, further comprising an access sheath comprising a sheath body having an inner diameter defining a working lumen between proximal and distal ends of the sheath body and a proximal connector fitting.

18. The system of claim 17, wherein: The distal portion of the catheter is sized to be positioned within the access sheath, and wherein a difference between (a) at least one outer diameter of the distal portion and (b) an inner diameter of the access sheath at an overlap region is less than 0.002".

19. The system of claim 17, further comprising an aspiration pump coupled to the proximal connector fitting and configured to transmit a suction force sufficient to perform aspiration thrombectomy through the catheter to a distal end of the distal portion of the catheter.

20. The system of claim 17, wherein: The access sheath has a length between a proximal end of a sheath body and a distal end of the sheath body suitable for positioning the distal end of the sheath body at the petrous portion of the internal carotid artery from a transfemoral approach.

21. The system of claim 17, wherein: The sheath body has a visual indicia near a distal end of the sheath body.

22. The system of claim 21, wherein: The distal portion of the catheter has one or more visual markings near a distal end of the distal portion.

23. The system of claim 22, wherein: Alignment of the one or more visual markings of the catheter with the visual markings of the sheath body indicates that the catheter is positioned at a distal-most position with a minimum overlap length to create a seal between the catheter and the sheath body.

24. The system of claim 22, wherein: The visual indicia of the sheath body is different from the one or more visual indicia of the catheter.

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