Rapid aspiration thrombectomy system and method

Abstract

To provide an intravascular access system for facilitation of intraluminal medical procedures within neuro vasculature through an access sheath.SOLUTION: The system includes an aspiration catheter or a support catheter having a flexible distal luminal portion having an inner diameter defining a lumen extending between a proximal opening at a proximal end of the luminal portion and a distal opening at a distal end of the luminal portion. The catheter has a rigid spine coupled to at least the proximal end of the luminal portion and extending proximally therefrom. The system includes a flexible distal dilator portion sized to be received within the lumen of the luminal portion. Associated systems, devices, and methods of use are also described.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 62 / 111,481, filed February 4, 2015, and U.S. Provisional Application No. 62 / 142,637, filed April 3, 2015, the disclosures of each of which are incorporated herein by reference in their entireties.

[0002] This application is also related to the following U.S. patent applications, the entire contents of which are incorporated herein by reference: (1) U.S. patent application Ser. No. 14 / 576,953, filed December 19, 2014; (2) U.S. patent application Ser. No. 14 / 569,365, filed December 12, 2014; (3) U.S. patent application Ser. No. 14 / 537,316, filed November 10, 2014; and (4) U.S. patent application Ser. No. 14 / 221,917, filed March 21, 2014. [Background technology]

[0003] The present disclosure relates generally to medical methods and devices for the treatment of acute ischemic stroke. More particularly, the present disclosure relates to methods and systems for navigating complex anatomy to perform rapid and safe aspiration and removal of cerebral infarcts.

[0004] Acute ischemic stroke is a sudden blockage of adequate blood flow to a portion of the brain, usually caused by a clot or other embolus that has become lodged or formed in one of the blood vessels that supply blood to the brain. If this blockage is not quickly relieved, ischemia may result in permanent neurological damage or death. The time frame for effective treatment of stroke is within 3 hours for intravenous (IV) thrombolysis, 6 hours for site-specific intra-arterial thrombolysis, and up to 8 hours for interventional recanalization of an occluded cerebral artery. Reperfusion of the ischemic brain after this time period provides no overall benefit to the patient and may actually be harmful by increasing the risk of intracranial hemorrhage with the use of fibrinolytic agents. Even within this time frame, there is strong evidence that the shorter the time from onset to treatment, the better the outcome. Unfortunately, it is rare to have the time frame in which symptoms can be noticed, the patient transported to a place of stroke treatment, and ultimately, these patients can be treated within this time frame. Despite advances in treatment, stroke remains the third leading cause of death and the leading cause of severe long-term disability in the United States.

[0005] Endovascular treatment of acute stroke consists of intra-arterial administration of thrombolytic drugs such as recombinant tissue plasminogen activator (rtPA), mechanical removal of the blockage, or a combination of the two. As mentioned above, these interventional procedures must be performed within hours of onset. Both intra-arterial (IA) thrombolysis and interventional thrombectomy involve accessing the occluded cerebral artery via endovascular techniques and devices.

[0006] As with IV thrombolysis, IA thrombolysis alone is limited in that it requires several hours of infusion to effectively dissolve the clot. Interventional thrombectomy involves the use of snares, coils or temporary stents (also known as retrievable stent devices) to capture and remove the clot, followed by aspirating the clot with or without further disruption of the clot. Retrievable stent devices are used to rapidly restore flow to the vessel during interventions. Hybrid procedures combining retrievable stent devices with aspiration through a guide or intermediate catheter are also used to aid in the removal of the clot and reduce the risk of distal embolism. Finally, balloons or stents have been used to create a patent lumen through the clot when removal or dissolution of the clot is not possible.

[0007] To access the cerebral anatomy, a guide catheter or guide sheath is used to guide an interventional device from an arterial access site, typically the femoral artery, to the target anatomy. A balloon guide catheter is often used to allow proximal carotid occlusion during the procedure, which may liberate high levels of emboli. Proximal occlusion has the effect of preventing forward flow and increasing the efficiency of aspiration through the lumen of the guide catheter. The length of the guide is determined by the distance between the access site and the desired location of the guide distal tip. Interventional devices such as guidewires, microcatheters, and intermediate catheters used for sub-selective guides and aspiration are inserted through the guide and advanced to the target site. Often the devices are used coaxially, i.e., a guidewire in a microcatheter within an intermediate catheter is advanced in stages as an assembly to the target site, advancing the inner most atraumatic element distally first, protecting the advancement of the outer elements. 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 an intermediate catheter is typically 20-40 cm longer than the working length of a guide, the working length of a microcatheter is typically 10-30 cm longer than the working length of an intermediate catheter, and the guidewire is typically 20-50 cm longer than the microcatheter. Summary of the Invention [Problem to be solved by the invention]

[0008] Some typical problems with current technology include the time required to access or at least the availability of access to the occluded site, the time required to restore flow or the inability to fully or at least partially restore flow to the vessel, and the occurrence of distal embolism during the procedure potentially having negative neurological effects and procedural complications such as perforation and intracerebral hemorrhage. What is needed are device systems and methods that allow rapid access, potentially resolving emboli, optimized aspiration of clots, distal protection throughout all stages of the procedure, and safe and rapid device exchanges required to fully restore flow to occluded cerebral vessels. [Means for solving the problem]

[0009] In one aspect, an endovascular access system for facilitating endoluminal neurovascular medical procedures through an access sheath is disclosed. The system includes an aspiration or support catheter having a flexible distal lumen having an inner diameter defining a lumen extending between a proximal opening at a proximal end of the lumen and a distal opening at a distal end of the lumen. The catheter has a rigid spine coupled to at least the proximal end of the lumen and extending proximally from the lumen. The system includes a dilator having a flexible distal dilator portion sized to be received within the lumen of the lumen and a rigid dilator spine extending proximally from the dilator portion.

[0010] The dilator spine may be aligned side-by-side with the spine of the catheter. The distal dilator section may have a tapered distal tip. The dilator has a length at least as long as the catheter such that the distal tip of the dilator can protrude from the distal opening of the lumen. The dilator may be generally tubular along at least a portion of its length. The proximal end of the catheter spine may include a gripping mechanism configured to be gripped by a user to move the catheter through the access sheath. The proximal end of the dilator spine may include a tab configured to be locked to a gripping mechanism on the catheter spine. When the catheter and dilator are locked, they may be advanced as a single unit through the access sheath. The gripping mechanism and the dilator tab may be removably coupled such that in a locked configuration the dilator tab engages the gripping element and in an unlocked configuration the dilator tab disengages from the gripping element. 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 section can include one or more detents on an outer surface configured to engage correspondingly shaped surface features on the inner surface of the intraluminal lumen through which the dilator section extends. The dilator spine and the catheter spine can have similar stiffness and kink resistance. The dilator can have visual markers at the distal and / or proximal ends of the distal tip. The distal end region of the dilator can be more flexible and become stiffer toward the proximal end region of the dilator. The catheter spine and the dilator spine can be configured to effect bidirectional sliding movement of the lumen through the lumen of the access sheath and advance the lumen into the cerebral vasculature to reach the treatment site.

[0011] In a related aspect, an intravascular access system for facilitating intraluminal neurovascular medical procedures is disclosed having 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 end region of the sheath body. The aspiration or support catheter has a flexible distal lumen having an outer diameter dimensioned for insertion through the lumen of the access sheath, a proximal opening at the proximal end of the lumen, an inner diameter defining a lumen extending between the proximal opening and the distal opening at the distal end of the lumen, and a length between the proximal and distal openings. The aspiration or support catheter includes a rigid spine coupled to at least the proximal end of the lumen and extending proximally therefrom. The rigid spine is configured to effect bidirectional sliding motion of the lumen through the lumen of the access sheath, exiting the at least one opening and advancing the lumen into the cerebral vasculature to reach the treatment site, and a portion of the outer diameter of the lumen fluidly seals with the inner diameter of the access sheath when a distal end of the lumen extends into the cerebral vasculature to reach the treatment site.

[0012] The lumen and the sheath body can be concentrically aligned, and the lumen of the lumen and the lumen of the sheath body form a continuous aspiration lumen from the distal end of the lumen to the proximal end of the sheath body. The continuous aspiration lumen can be used to aspirate fluids and debris from the distal opening of the lumen. The continuous aspiration lumen can deliver material through the distal opening of the lumen. The continuous aspiration lumen can form an increase in diameter where the contents of the lumen of the lumen are entirely transferred into the lumen of the sheath body. The lumen of the lumen can be shorter than the lumen of the sheath body. The lumen and the sheath body can form an overlap region where the lumen extends distally beyond at least one opening of the sheath body. The outer diameter of the lumen can approach the inner diameter of the lumen of the sheath body, such that the overlap region forms a seal. The seal can be configured to be capable of sealing against a vacuum of up to 25 inHg or up to 28 inHg. The seal in the overlap region can be configured to be capable of sealing against pressures of up to 300 mmHg or up to 600 mmHg or 700 mmHg. The seal can be located distal to the proximal end of the lumen and proximal to the at least one opening in the sheath body.

[0013] The system may further include a sealing element disposed on an outer surface of the lumen. The sealing element may include an increasing diameter or protruding feature in the overlap region. The sealing element may include one or more external ridge features. The one or more ridge features may be compressible when the lumen is inserted into the lumen of the sheath body. The sealing element may include one or more angled surfaces biased against an inner surface of the sheath body lumen. The sealing element may include one or more expandable members that are 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.

[0014] The sheath body can have a length between the proximal and distal ends suitable for positioning the distal end of the sheath body into 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 can be between 10 cm and 25 cm. The length of the lumen can be shorter than the length of the sheath body such that when the catheter is retracted into the sheath body, a seal remains between the overlap region of the lumen and the inner diameter of the sheath body.

[0015] The spine can be longer than the entire length of the sheath body. The lumen can include three or more layers, including an inner lubricated liner, a reinforcing layer, and an outer jacket layer. The outer jacket layer can be composed of separate sections of polymer having different durometers, compositions, and / or thicknesses to vary flexibility along the length of the distal lumen. The outer diameter of the distal lumen can be sized for movement into the cerebral artery. The inner diameter of the distal lumen can be between 0.040 inches and 0.088 inches. The outer diameter of the lumen can be close to the inner diameter of the sheath body, thereby allowing the catheter to move through the sheath body while forming a sealed area at the overlap area. The catheter can be tapered toward the distal opening such that the distal-most end of the lumen has a smaller outer diameter compared to more proximal regions of the lumen near where the lumen seals with the sheath body. The distal end region of the sheath body can include an occlusion element. The distal end region of the sheath body can include an extended distal tip. The at least one opening from the lumen can include a lateral opening disposed a distance away from the distal tip of the sheath body. The distal tip of the sheath body can further include a beveled feature configured to direct the catheter outwardly from a longitudinal axis of the sheath body lumen through the at least one opening.

[0016] The spine may be longer than the overall length of the sheath body. The spine may be a wire having an outer dimension of 0.014 inches (0.014") to 0.018 inches (0.018"). The spine may be a hypotube having a guidewire passageway extending therethrough. The spine may be a ribbon having an outer dimension of 0.010 inches (0.010") to 0.025 inches (0.025") thick. The ribbon may be curved along at least a portion of an arc. The spine may be configured to rotate the lumen about a longitudinal axis of the access sheath. The spine may be eccentrically coupled to the lumen, the spine extending proximally from the lumen outside the proximal end of the sheath body. The proximal end of the lumen may have an angled cut. The angled cut may be generally planar or curved. The sheath body may have one or more visual markers at a distal end region of the sheath body. The distal lumen may have one or more visual markers at a distal end region of the lumen, a proximal end region of the lumen, or both. The one or more visual markers on the sheath body can be visually distinct from the one or more visual markers on the lumen. The spine can have one or more visual markers. The one or more visual markers on the spine can indicate an overlap between the distal lumen and the sheath body. The one or more visual markers on the spine can be positioned such that when the visual markers on the spine are aligned with a portion of the access sheath, the catheter is positioned in a distal-most position having the shortest overlap length required to form a seal between the catheter and the sheath body.

[0017] The system may further include a flexible distal dilator section having a distal tip and sized to be received within the lumen 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 malleable material configured to be shaped by a user. The dilator may further include a rigid dilator spine extending proximally from the dilator section. The dilator spine may be coaxial and may have a lumen extending therethrough. The dilator spine may be eccentric. In use, the dilator spine may be aligned side-by-side with the spine of the catheter. The distal tip of the dilator may be tapered. The dilator may have a length at least as long as the length of the catheter such that the distal tip protrudes from the distal opening of the lumen. The proximal end of the spine may include a gripping mechanism configured to be gripped by a user to move the catheter through the access sheath. The proximal end of the dilator spine may include a tab configured to engage with a gripping mechanism on the catheter spine. When the catheter and dilator are in the locked configuration, they can be advanced as a single unit through the sheath body. The gripping mechanism and dilator tabs can be removably coupled such that in the locked configuration, the dilator tabs engage the gripping elements and in the unlocked configuration, the dilator tabs disengage from the gripping elements. The dilator tabs 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.

[0018] The distal dilator section can include one or more detents on an outer surface configured to engage with correspondingly shaped surface features on an inner surface of the lumen through which the dilator section extends. The dilator spine and the catheter spine can have similar stiffness and kink resistance. The dilator can have visual markers at the distal and / or proximal ends of the distal tip. The distal end region of the dilator can be more flexible and become stiffer toward the proximal end region of the dilator. The catheter spine and the dilator spine can be configured to effect bidirectional sliding movement of the lumen through the lumen of the access sheath and advance the lumen into the cerebral vasculature to reach the treatment site.

[0019] The access sheath may further include a connector connecting the proximal end of the sheath body to the proximal hemostatic valve. The proximal hemostatic valve may have an adjustable opening sized to be large enough to remove the catheter without dislodging the clot thereon. When used with the access sheath, the stiff spine of the catheter may extend proximally from the lumen through the access sheath lumen and out of the proximal hemostatic valve of the access sheath. The connector may provide a connection to an aspiration line at the proximal end of the sheath body. The connector may have a large diameter lumen and may be connected to a large diameter aspiration line. The aspiration line may be connected to a suction source. The aspiration source may be an active suction source. The aspiration line may be connected to a forward drip or irrigation line. The access sheath may further include a proximal extension such that when the distal lumen of the catheter is withdrawn from the sheath body lumen, it remains within the proximal extension. The inner diameter of the lumen may be sized to allow for placement of an interventional device through the lumen.

[0020] Other features and advantages will be apparent from the following description of various embodiments which illustrate, by way of example, the principles of the invention. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an example of an exploded view of a system of devices for accessing and removing a cerebral occlusion to treat acute ischemic stroke from a femoral artery access site. [Figure 2A] FIG. 2A shows the components of the system of FIG. 1 in place in a patient via a transfemoral approach for treatment of the occlusion. [Figure 2B] FIG. 2B is a detailed view of a portion of the system of FIG. 2A, taken along the cross-section along circle BB. [Diagram 3] FIG. 3 illustrates the components of the system of FIG. 1 used via a transcarotid access site. [Figure 4] FIG. 4 illustrates an embodiment of an access sheath. [Diagram 5] FIG. 5 shows an embodiment of the proximal portion of the access sheath of FIG. 4 provided as a separate, removable component. [Figure 6] FIG. 6 illustrates an embodiment of a connector for minimizing flow resistance through the access sheath of FIG. 4 to the proximal end. [Figure 7] FIG. 7 illustrates an embodiment of an access sheath having an occlusion balloon. [Figure 8A] FIG. 8A illustrates an embodiment of a sealing element between the access sheath body and the lumen of the catheter extending therethrough. [Figure 8B] FIG. 8B illustrates an embodiment of a sealing element between the access sheath body and the lumen of the catheter extending therethrough. [Figure 9] FIG. 9 shows an embodiment of a microcatheter and retrievable stent device placed through a spine catheter. [Figure 10A] FIG. 13 shows an embodiment of an expandable portion on a retrieveable stent device. [Figure 10B] FIG. 13 shows an embodiment of an expandable portion on a retrieveable stent device. [Figure 10C]FIG. 13 shows an embodiment of an expandable portion on a retrieveable stent device. [Figure 11] FIG. 11 illustrates an embodiment of an aspiration system for use in the systems described herein. [Figure 12A] FIG. 12A illustrates an embodiment of a spined catheter system for use in the systems described herein. [Figure 12B] FIG. 12B shows the spined catheter system of FIG. 12A with a spined dilator extending through the lumen of the spined catheter. [Figure 12C] FIG. 12C shows the spined catheter system of FIG. 12A extending through a side opening of an embodiment of an access sheath. [Figure 13] FIG. 13 is a cross-sectional view taken along line AA in FIG. 12B. [Figure 14] FIG. 14 is a cross-sectional view taken along line BB in FIG. 12B. [Figure 15A] FIG. 15A shows an embodiment of a spined aspiration catheter-dilator system having a spined catheter and a spined dilator in a locked configuration. [Figure 15B] FIG. 15B shows a spined aspiration catheter-dilator system having a spined catheter and a spined dilator in an unlocked configuration. [Figure 16] FIG. 16 shows an embodiment of a spined catheter system extending distally to an access sheath for treating an embolus in a cerebral vasculature. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] One of the major drawbacks of current acute stroke intervention procedures is the time required to restore blood perfusion to the brain. This time includes the time required to access the site of occlusion in a cerebral artery and the time required to completely remove the arterial occlusion. Multiple attempts are often required to completely remove the occlusion, and reducing the number of attempts, along with the time required to exchange the device for additional attempts, are key factors in minimizing the overall time. Furthermore, each attempt is associated with potential procedural risks due to advancement of the device in the delicate cerebral vasculature.

[0023] Disclosed herein are methods and devices that allow safe and rapid access to and removal of occlusions from the complex neurovascular anatomy of the brain and intracranial arteries. The methods and devices include one or more access devices, catheters, and thrombectomy devices for removing occlusions. Disclosed herein are methods and devices that provide active aspiration and / or passive backflow to facilitate removal of occlusions as well as minimize distal emboli. The systems provide the user with a degree of flow control to address the specific hemodynamic demands of the cerebral vasculature. The systems described herein provide superior ease of use in that a single operator can operate the disclosed system using single-point continuous aspiration for rapid and safe exchange without changeover. The high efficiency of aspiration provided by the systems described herein reduces distal embolic debris and increases the speed of "one-pass" thrombectomy.

[0024] Although some embodiments are specifically described with respect to aspirating neurovascular anatomy, it is understood that the embodiments are not so limited and may be applicable to other applications. For example, the spined aspiration catheter and one or more components of the access system described herein may be used to deliver a working device to a target vessel in the coronary anatomy or other vascular anatomy. Where the phrase "aspiration catheter" is used herein, it is also understood that the catheter may be used for other purposes other than or in addition to aspiration, such as for delivery of fluids to a treatment site or as a support catheter that provides a conduit to facilitate and guide the delivery or exchange of other devices, such as a guidewire or interventional device. Alternatively, the access system need not be limited to the vasculature, but may be useful for accessing other parts of the body outside the vasculature. It is also understood that throughout this specification, certain features, structures, configurations, features, or implementations or embodiments may be combined in any suitable manner. Relative terms may be used throughout this specification to indicate relative positions or directions. For example, "distal" may indicate a first direction away from a reference point. Similarly, "proximal" can refer to 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 anchoring delivery system to the particular configurations described in the various embodiments below.

[0025] FIG. 1 illustrates a system of devices for accessing and removing cerebral occlusions to treat acute ischemic stroke from a femoral artery access site. The system 100 includes an access sheath 220, a sheath dilator 250, a guidewire 270, one or more spined aspiration or support catheters 320, a dilator 340, a microcatheter 400, and a retrievable stent device 500, each of which is described in detail below. Additionally, the system 100 can include one or more arterial access sheath systems 200, including the access sheath 220, one or more sheath dilators 250, and a sheath guidewire 270. The system 100 can include one or more spine catheter systems 300, including a spined aspiration or support catheter 320, a tapered dilator 340, or a catheter clearing tool 350. The spine catheter system 300 can incorporate a nested spine catheter to provide extended reach to distal sites. The system 100 can include an access sheath system 200 , a tapered catheter system 300 , a microcatheter 400 , and a retrievable stent device 500 .

[0026] 2A shows several components of the system being placed in place in a patient via a transfemoral approach for treatment of an occlusion. An access sheath 220 can be inserted through a femoral artery insertion site with the distal tip of the access sheath 220 positioned at or near the petrous portion of the internal carotid artery ICA. A spined aspiration catheter 320 can be positioned with its distal tip at the occluded aspect of the artery. In some embodiments, the access sheath 220 can be advanced to the internal carotid artery by being inserted through a direct puncture in the wall of the common carotid artery rather than via a transfemoral approach (see FIG. 3).

[0027] As can be seen more clearly in detailed FIG. 2B, the access sheath 220 can have a sheath body 222 and an inner lumen 223 extending between the proximal and distal end regions of the sheath body 222. The spined aspiration catheter 320 is sized and extends through the inner lumen 223 of the access sheath 220 such that the distal end region of the catheter 320 extends beyond the distal end region of the access sheath 220. The catheter 320 is shown in FIG. 2B to exit the lumen 223 of the sheath body 222 through a distal opening 221. However, as described in more detail below, the sheath body 222 can have one or more side openings near the distal end region of the body 222 through which the catheter 320 can extend (see FIG. 12C).

[0028] 2B, the spined aspiration catheter 320 can include a relatively flexible distal lumen 322 coupled to a stiff, kink-resistant proximal spine 330. The distal lumen 322 can have an internal lumen 323 extending between the proximal and distal ends of the lumen 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 coupled and in contact to allow for the flow of fluid into and / or out of the system, such as by drawing from a suction source coupled to the system via a connector 226 on the access sheath 220. The overlap region 120 between the distal section of the sheath body 222 and the lumen 322 of the catheter 320 is sized and configured to allow for a continuous aspiration lumen from the distal tip region of the spined catheter 320 to the proximal sheath connector 226. If the sheath body 222 has a side opening through which the distal lumen 322 of the catheter 320 extends, the seal formed in the overlap region 120 between the sheath body 222 and the lumen 322 is disposed proximate the side opening.

[0029] The key dimensions that affect the suction force through a tube include radius (r), pressure (P), viscosity (n), and length (L), and flow rate = Q = πr 4(ΔP) / 8nL. A change in radius increases the flow rate by its fourth power, and length is inversely proportional to the flow rate. As described in more detail below, the aspiration catheter has an over-the-wire portion for a portion of the total distance required to reach the target site. This configuration significantly reduces the time required to retract and re-advance the catheter. Additionally, the systems described herein can provide significantly increased radius and lumen area for clot aspiration, as well as significantly shorter lengths, particularly compared to conventional systems in which the aspiration lumen extends along the entire inner diameter of the aspiration catheter. In the systems described herein, the majority of the aspiration lumen has the radius of the procedural sheath. Although the catheter 320 has a smaller diameter than the guide, the lumen diameter increases as it reaches the lumen of the access sheath 220, allowing for significant aspiration forces to be applied over the majority of the length of the lumen system. Additionally, the overall length of this narrow diameter region of the catheter 320 is very short compared to the overall length of the access sheath. The proximal spine 330 of the catheter 320 has a length and structure that extends through the lumen 223 of the access sheath 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 aspiration catheter 320 only partially occludes the luminal space, increasing the luminal area for aspiration of the system. The increased luminal area for aspiration increases the time it takes to aspirate the occlusion and increases the likelihood of clearing the occlusion in one aspiration attempt. With a device such as a microcatheter or tapered dilator coaxially positioned within the spine catheter 320 and the access sheath 220, the increased luminal diameter also increases the luminal area available for forward flushing of contrast, saline, or other solutions. This can facilitate and enhance the ability to perform angiograms during device movement.

[0030] Current stroke interventions pose a risk of distal occlusion being released. During efforts to remove or dissolve thrombus occlusions in cerebral arteries, for example, there is a significant risk of thrombus fragmentation, which can generate occlusive particles that can travel downstream to reach either the occluded vessel or other defects and impair cerebral perfusion. In carotid artery stenting procedures (CAS), embolic protection devices and systems are commonly used to reduce the risk of embolic material entering the cerebral vasculature. This type of device includes intravascular distal filters, and reverse flow or static flow systems. Unfortunately, due to the need for rapid intervention, as well as delicate anatomy and access challenges, these types of embolic protection systems have not been used in acute ischemic stroke interventional treatments. The period of stroke intervention when flow is restored is usually considered to be a critical time when the brain is now perfused with blood. However, it is also a period of embolic risk. While there is an occlusion in the artery, there is no flow. Thus, any embolic debris created by crossing the embolus with a guidewire and / or microcatheter, or by placing a retrievable stent device across the occlusion, will remain stagnant, but when flow is restored to the artery, the embolus will flow antegrade to distal vascular territories.

[0031] The second period of embolic risk occurs when the retrievable stent device is retracted into the guide or catheter. In conventional methods and devices, suction is applied to the intermediate catheter while the retrievable stent device is retracted into the catheter, or the catheter and retrievable stent device are retracted together into the guide while suction is applied to the guide catheter. Two-point suction, one through the catheter and one through the guide, may both be used to reduce the risk of distal embolism during the critical step of removing emboli from the patient through the guide. Often, two people are required to enable two-point suction, or suction is applied sequentially, first from the catheter and then from the guide, which may result in interrupted or suboptimal suction. In the disclosed systems and methods, backflow may be applied to the target site at a single suction point during the critical time of flow restoration as the device is advanced and during the entire time that emboli are removed.

[0032] In one aspect of the present disclosure, the level of suction may be varied from a low level that achieves adequate protection from distal embolism to a high level that provides effective suction for embolic removal. This aspect allows for distal protection without high levels of blood loss, yet allows for the strong suction required for embolic removal.

[0033] In another aspect, methods and devices are disclosed for further providing active aspiration or passive retrograde flow during procedures to remove thrombus and minimize distal embolism. The system provides the user with a degree of flow control to address the specific hemodynamic demands of the cerebral vasculature. The system includes a flow controller that allows the user to adjust the timing and mode of aspiration.

[0034] In another aspect, methods and devices are disclosed that further provide a washing step to minimize emboli entrapment in the system and to increase visualization of particles in the system during use.

[0035] The following description provides detailed implementations and advantages of each aspect of the disclosed invention.

[0036] 1, which illustrates an embodiment of an access sheath 220. The sheath 220 includes a sheath body 222, which is 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 include a proximal extension 240 and may also include a valve on the connector 226 that fluidly isolates the sheath body 222 from the proximal portion 240 of the access sheath 220. The access sheath 220 may be a kit with one or more dilators 250 and a sheath guidewire 270.

[0037] The diameter of the sheath body 222 is suitable for insertion into the carotid artery and has an inner lumen 223 suitably sized to provide a passageway for a catheter to treat the embolus. In one embodiment, the sheath body 222 has an inner diameter of about 0.074 inches (0.074") and an outer diameter of about 0.090 inches (0.090") corresponding to a 5 French sheath size, an inner diameter of about 0.087 inches (0.087") and an outer diameter of about 0.104 inches (0.104") corresponding to a 6 French sheath size, or an inner diameter of about 0.100 inches (0.100") and an outer diameter of about 0.177 inches (0.177") corresponding to a 7 French sheath size. The length of the sheath body 222 is configured to allow the distal tip of the sheath body 222 to be positioned as distally as possible in the petrous portion of the internal carotid artery. In one embodiment, the length of the sheath body 222 is suitable for a transfemoral approach and ranges from 80-90 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 transcarotid approach to the petrous ICA and ranges from 20-25 cm. In one embodiment, the length of the sheath body 222 is suitable for a transcarotid approach to the CCA or proximal ICA and ranges from 10-15 cm. The sheath body 222 is configured to navigate through bends in the vasculature and to be able to receive high suction forces without kinking, collapsing, or causing vascular trauma.

[0038] The sheath body 222 may be constructed of two or more layers. The inner liner may 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 jacket material may provide mechanical integrity to the inner liner and may be constructed of materials such as PEBAX, thermoplastic polyurethane, polyethylene, nylon, etc. A third layer may also be incorporated and may provide reinforcement between the inner liner and the outer jacket. The reinforcement layer may prevent flattening or kinking of the inner lumen of the sheath body 222, which may allow for smooth navigation of the device through bends in the vessel as well as aspiration or backflow. The sheath body 222 may be reinforced circumferentially. The reinforcement layer may be made of metals such as stainless steel, nitinol, nitinol braid, helical ribbon, helical wire, cut stainless steel, or a rigid polymer such as PEEK. The reinforcement layer may have a structure such as a coil or braid, or a tube that is laser cut or machine cut to provide flexibility. In another embodiment, the reinforcing layer may be a cut hypotube, such as a Nitinol hypotube or a cut rigid polymer.

[0039] The flexibility of the sheath body 222 can vary along its length, increasing in flexibility towards the distal portion of the sheath body 222. Varying flexibility can be accomplished in a variety of ways. For example, the outer jacket can vary in durometer and / or material in various sections. A lower durometer outer jacket material can be used in the distal portion of the sheath compared to other portions of the sheath. Alternatively, the jacket wall thickness can be reduced and / or the density of the reinforcement layer can be changed to increase flexibility. For example, the pitch of the coil or braid can be stretched or the cut pattern in the tube can be changed to be more flexible. Also, the reinforcement structure or material can vary along the length of the sheath body 222. In one embodiment, the most distal portion has a lower bending stiffness (E* I) range is 50-300N-mm 2 and the bending stiffness of the remaining part of the sheath body 222 is 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 embodiment, there is a transition section between the most distal flexible section and the proximal section, with one or more changes in flexibility between the most distal section and the remainder of the sheath body 222. In this embodiment, the most distal section is about 2 cm to about 5 cm, the transition section is about 2 cm to about 10 cm, and the proximal section makes up the remainder of the sheath length.

[0040] The tip of the sheath body 222 may include one or more distal radiopaque markers 224 (see FIG. 1). In one embodiment, the radiopaque markers 224 are metal bands, for example platinum iridium alloy, embedded near the distal end of the sheath body 222. Alternatively, the access sheath tip material may be a separate radiopaque material, for example a barium polymer blend or a tungsten polymer blend. The distal region of the sheath body 222 also extends into an overlap region 120 that allows for a seal between the catheter 320 and the sheath body 222, forming a continuous aspiration lumen. Thus, the outer diameter of the lumen 322 of the aspiration catheter 320 approaches the inner diameter of the distal region of the lumen 223 of the sheath body 222 so that a seal is formed. The relative location of the seal formed may vary depending on where the aspiration catheter 320 exits the lumen 223 of the sheath body 222 and the location of the opening from the sheath body 222, as described in more detail below. If the sheath body 222 has an opening at its distal end, the seal may be located closer to the distal end of the sheath body 222 than if the sheath body 222 had one or more side openings in the distal end region of the sheath body 222 through which the catheter 320 can exit the lumen 223.

[0041] Referring again to FIG. 1 , the access sheath 220 can 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 has a large diameter lumen and connects to a large diameter aspiration line 230. In one embodiment, the lumen of the connector 226 is at least 0.080 inches. In one embodiment, the lumen of the aspiration line 230 is at least 0.080 inches. The aspiration line 230 can terminate in a stopcock, female luer connector, or other connector 232 that allows for connection to a suction source. In one embodiment, the aspiration source is an active suction source, such as a syringe or pump. In another embodiment, the aspiration source is a retrograde shunt line, such as described in U.S. Pat. No. 8,157,760 and U.S. Patent Application Publication No. 2010 / 0217276, both of which are incorporated herein by reference. The large diameter aspiration line 230 can be configured to be resistant to collapse. For example, the aspiration line 230 can be a thick walled or reinforced polymer tube. The aspiration line valve 232 allows for opening and closing of the line 230. In one embodiment, the valve 232 also allows for connection to one or more additional fluid lines, such as for connection to a forward drip or irrigation line for contrast 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 include a means for securing the access sheath 220 to the patient to reduce the risk of sheath dislodgement during the procedure. For example, the connector 226 can include one or more suture eyelets 233.

[0042] 1, the proximal end of the access sheath 220 may terminate in a proximal hemostatic valve 234. This valve 234 allows for the introduction of devices through the sheath 220 into the vessel while preventing and minimizing blood loss and preventing air from entering the access sheath 220. The proximal hemostatic valve 234 may include an irrigation line 236 or a connection to an irrigation line 236 so that the sheath 220 can be irrigated with saline or radiopaque contrast agent during the desired procedure. The hemostatic valve 234 may be a statically sealed active valve, or a Touhy Borst valve or a rotating hemostatic valve (RHV). The hemostatic valve 234 may be integral with the access sheath 220, or the access sheath 220 may terminate at its proximal end in a female Luer adapter to which a separate hemostatic valve 234 component, such as a passively sealed valve, a Touhy Borst valve or a rotating hemostatic valve, may be attached. In one embodiment, valve 234 has an adjustable opening that is large enough to move a device with a clot attached to its tip during removal so that the clot is not dislodged by valve 234. Alternatively, valve 234 is removable and is removed when the tip of the catheter is removed from sheath 220 to prevent the valve 234 from dislodging the clot.

[0043] Referring again to FIG. 1, the arterial sheath system 200 can include one or more sheath dilators 250 and sheath guidewires 270. The sheath guidewires 270 can be first inserted into the artery using standard vascular access techniques such as the micropuncture technique or the modified Seldinger technique. The sheath dilators 250 allow smooth insertion of the access sheath 220 through the puncture site in the arterial wall. The dilators 250 can be inserted into the access sheath 220, and then the two elements are inserted together into the artery along with the sheath guidewire 270. The distal end 256 of the dilators 250 can generally have a tapered shape to allow the dilators 250 to dilate the needle puncture site as they are inserted into the artery through the arterial wall. The tapered distal end 256 can have a radiused tip and a total included angle (relative to the longitudinal axis of the dilator) generally between 6-12 degrees.

[0044] The lumen of the dilator 250 can accommodate the sheath guidewire 270 and can have an inner diameter of 0.037 inches to 0.041 inches, corresponding to the 0.035 inches to 0.038 inches of the sheath guidewire 270. Alternatively, the lumen of the dilator 250 can be 0.020 inches to 0.022 inches, corresponding to the 0.014 inches to 0.018 inches of the sheath guidewire 270. 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 of between 0.037 inches to 0.041 inches, and the inner dilator can have an inner diameter of between 0.020 inches to 0.022 inches. In use, the sheath 220 can be inserted into the artery with the outer dilator with the sheath guidewire 270 between 0.035 inches to 0.038 inches. The sheath guidewire 270 is then removed and replaced with an inner dilator and a smaller guidewire between 0.014 inches and 0.018 inches, and the access sheath 220 can then be advanced further distally to the desired site within the carotid artery.

[0045] For initial insertion of the arterial sheath 220 into the artery along the sheath guidewire 270, the dilator taper 256 can have a predetermined stiffness and taper angle to provide an appropriate expansion force at the arterial puncture site. However, it may be desirable to have a sheath dilator 250 with a softer and / or longer taper at the distal end than that used for initial arterial access to safely reach the petrous portion of the ICA. In one embodiment, the access sheath system 200 can include two or more tapered dilators. A first tapered dilator can be used with an arterial access device to advance into the artery, and thus can be sized and configured in a manner similar to a standard introducer sheath dilator. Examples of materials that can be used for the tapered dilator include, for example, high density polyethylene, 72D PEBAX, 90D PEBAX, or materials with comparable stiffness and lubricity. The second tapered dilator may have a softer distal section or portions having a lower bending stiffness and / or a longer taper length than the distal portion of the first tapered dilator. That is, the second dilator has a distal region that is softer, more flexible, or articulates or bends more easily than the corresponding distal region of the first dilator. Thus, the distal region of the second dilator bends more easily than the corresponding distal region of the first dilator. In one embodiment, the distal portion of the first dilator has a bending stiffness of 50-100 N-mm. 2 and the distal portion of the second dilator has a bending stiffness in the range of 5 to 15 N-mm 2 A second dilator (having a distal portion with a lower bending stiffness) can be exchanged for the initial first dilator such that the flexible distal portion of the second dilator can be advanced into the internal carotid artery and around the curvature of the artery without causing excessive force or trauma on the vessel.

[0046] The flexible, distal portion of the second dilator may be, for example, 35 or 40D PEBAX, with a proximal portion made of, for example, 72D PEBAX. A middle middle section or groups of middle middle sections may be included on the second dilator to provide a smooth transition between the flexible distal section and the stiff proximal section. In one embodiment, both dilators have an inner diameter between 0.037 inches and 0.041 inches. In another embodiment, the first dilator has an inner diameter between 0.037 inches and 0.041 inches, and the second dilator has an inner diameter between 0.020 inches and 0.022 inches. In yet another embodiment, the second dilator is a two-piece 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 to allow the location of the tip of the dilator to be visible under fluoroscopy. In one version, the radiopaque marker 224 is a tungsten-loaded PEBAX or polyurethane section that is heat welded to the distal tip of the dilator. Other radiopaque materials may be used to form the radiopaque marker 224 at the distal tip as well.

[0047] In one embodiment, the access sheath 220 includes a proximal extension 240 that extends between the connector 226 and the proximal hemostatic valve 234. In the transcarotid configuration of the system, it may be desirable to move the proximal hemostatic valve 234 away from the distal tip of the access sheath 220, effectively stretching or lengthening the proximal portion of the access sheath outside the body while maintaining the length of the insertable sheath body 222. This allows the user to insert the device into the proximal hemostatic valve 234 of the access sheath 220 from a location farther away from the target site and therefore from the x-ray source and / or image intensifier used to fluoroscopically image the target, thereby minimizing radiation exposure to the user's hands and his or her entire body. In this embodiment, the proximal extension 240 may be in the range of 10-25 cm, or in the range of 15-20 cm. In either the transcarotid or transfemoral configuration, it is desirable to have a portion of the access sheath 220 fluidly connected to the access sheath aspiration line, which may extend proximally from the aspiration line connection, allowing the user to withdraw the device from the blood flow from the sheath tip to the aspiration line without having to completely remove the device from the access sheath 220.

[0048] In another embodiment, it may be desirable to intermittently isolate the proximal portion 240 from the sheath body 222. In one embodiment, as shown in FIG. 4, the connector 226 includes a valve 242 that closes 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 hemostatic valve 234. This allows the distal portion of a catheter, retrieval stent device, or other thrombus removal device to be retracted into the proximal extension 240 without arterial bleeding from the sheath 220, the valve 242 to be closed to fluidly isolate the sheath body 222 from the proximal portion of the sheath, and then the proximal hemostatic valve 234 can be opened wide or removed, or the entire proximal extension 240 of the sheath 220 can be removed. To completely remove the catheter 320 from the sheath 220, the proximal extension 240 can have at least the same length as the distal lumen 322 of the spine catheter 320, so that the distal lumen 322 is fully retracted into the proximal extension 240 and the valve 242 is closed before the proximal hemostasis valve 234 is opened wide.

[0049] Also, after the clot removal device or other interventional device is retracted into this proximal extension 240 and the sheath body 222 is closed with the valve 242, a portion of the clot removal device, for example the distal lumen 322 of the aspiration catheter 320, may remain in the proximal extension 240 and be washed or cleaned by creating a flow from a flush line to an aspiration line to remove clots without completely removing the device 320 from the access sheath 220. This ability to flush and clean the clot removal device without completely removing the device can reduce bleeding, time, and risk of air embolism during the procedure. Also, retracting the clot removal device into the proximal extension 240 during flushing and cleaning without completely removing the device from the sheath body 222 can minimize the risk of operator or staff coming into contact with blood or debris resulting from cleaning the device. In any of these embodiments, the proximal extension tube is clear so that the flushing fluid and the presence / absence of embolic debris or air can be viewed through the tube.

[0050] The proximal extension 240 of the access sheath 220 can be provided as a separate, removable member that can be attached to any sheath with a standard connection at its proximal end. As shown in FIG. 5, the proximal member 280 includes a connector 285 that can be connected to the proximal hub 15 of a standard sheath 10. The connected members form an assembly having the configuration and features of the access sheath 220. In this embodiment, the user can select from several available sheaths having the appropriate length, shape, and mechanical characteristics for the procedure and perform the steps of the procedure described in this disclosure. The removable proximal member 280 can include the Y-arm connector 226, the aspiration line 230, the proximal extension 240, the proximal hemostasis valve 234, and the irrigation line 236, along with 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 of the sheath 220. In one embodiment shown in FIG. 6, the connector 285 is configured to minimize flow resistance through the sheath 10 and into the proximal portion 280. For example, instead of a standard male-female luer connection, the connector 285 includes an adapter 60 having a lumen and a face that mates with a standard female luer connector 62 commonly found on a sheath, a seal member 64 that seals between the adapter 60 and the sheath female luer 62, and a rotating nut 66 that engages a threaded portion of the female luer 62 such that the seal 64 is compressed to seal against fluids, air vacuum, and pressure, connecting the adapter 60 and the luer 62 together. Returning again to FIG. 5, the proximal member 280 may include a valve 242 on the Y-arm connector 226 so that when the proximal member 280 is connected to the sheath 10, the proximal portion can selectively open or close the fluid connection with the sheath 10. A similar type of connection can be made for the connector 232 that connects the sheath suction line 230 to the suction source.

[0051] In a preferred embodiment, the proximal connection has a proximal extension about 22 cm long, a Y-arm connector about 7 cm long, and a proximal hemostatic valve about 5 cm long, for a total length of about 34 cm.

[0052] During some portions of the procedure, it may be desirable to temporarily occlude the carotid artery during the intervention to prevent antegrade flow of emboli. In one embodiment, as shown in FIG. 7, the access sheath 220 includes an occlusion balloon 246 at the distal tip of the sheath body 222. An additional lumen within the sheath body 222 can be connected to an inflation line 248 to fluidly connect the balloon 246 to the inflation line 248. An inflation device is connected 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 required.

[0053] In some instances, it may be desirable to keep the sheath tip as small as possible during sheath insertion, but expand the opening of the sheath 220 after insertion into the vessel to minimize the diameter of the arterial puncture. At least one purpose of this feature is to minimize the effect or creation of a distal occlusion when the aspiration catheter 320 is retracted or another clot removal device is retracted into the sheath 220. During a clot removal procedure, a thrombus may be "pulled back" into the distal opening 221 of the sheath 220 on the device that captured the thrombus. If the distal tip of the sheath 220 is enlarged or funneled compared to its initial size, the likelihood of the thrombus fragmenting and causing an embolism is minimized because the larger dimensions or funneled shape of the sheath tip increases the likelihood that an embolus will be drawn into it without breaking into multiple pieces. This results in a more favorable clinical outcome for the patient. In one embodiment of the access sheath, the distal portion of the sheath body 222 is selected in material and / or construction to allow the tip to expand after the sheath 220 is inserted into the artery and placed in the desired location. In one embodiment, the distal region, which has an ID of about 0.087 inches, can expand to a diameter of about 0.100 inches to 0.120 inches, and may vary and / or be flared in size.

[0054] An example of an expanding distal tip configuration includes a covered braided tip that can be contracted to expand. Another example of an expanding distal tip is an umbrella or similar structure that opens when unconstrained by a mechanical drive or elastic spring. Other mechanisms for expanding diameter are known. One specific embodiment is a sheath made of a material that is deformable when expanded with a high pressure balloon. Exemplary devices are described in co-pending U.S. Patent Publication No. 2015 / 0173782, filed Dec. 19, 2014, and incorporated herein by reference in its entirety. Configurations of this feature are described in co-pending U.S. Patent Publication No. 2015 / 0173782.

[0055] The location, size and number of openings may also vary in the distal end region of the sheath body 222. The sheath body 222 may incorporate one or more openings near the distal end region of the sheath 220 that allow fluid to flow between the lumen 223 of the sheath body 222 and the blood vessel in which the sheath 220 is disposed. The one or more openings may be sized to allow the lumen 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 322 such that the one or more openings may form an elongated mouth, slot or notch in the distal end region of the sheath body 222. The one or more openings can be formed in a region of the sidewall of the sheath body 222 immediately proximate 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 away from the distal end of the sheath body 222. The one or more openings can be a plurality of openings forming a porous region proximate the distal end region of the sheath body 222, with at least one of the plurality of openings being sized large enough to allow one or more members 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 FIGS. 4 and 12C). In some embodiments, the one or more openings include an elongated distal port that forms a side opening 1219 located on a first surface of the sheath body 222 near the distal end region (see FIG. 12C). The side opening 1219 can be located at least 0.25 mm or more away from the distal end of the sheath body 222. The side opening 1219 can have a diameter at least the same as the outer diameter of the distal lumen 322 of the spined catheter 320. Preferably, the side opening 1219 has a diameter at least 1.5, 2, 2.5, or 3 times larger than the outer diameter of the distal lumen 322.In another embodiment, the sheath body 222 includes a pair of side openings 1219 on opposing and / or adjacent faces of the sheath body 222 near the distal end 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 to position the one or more openings 1219 to allow distal expansion of the catheter 320 from the side openings 1219 in a desired direction relative to the longitudinal axis A of the sheath 220. The introduction of the wide-mouthed side openings 1219 can change the range of exit angles of the catheter 320 from a position that is substantially (i.e., nearly) parallel to the sheath body 222 to a position that is angled relative to the sheath body 222, e.g., greater than 90 degrees, as well as a position that is substantially perpendicular or perpendicular to the sheath body 222. This placement can be very important in situations where there is severe angulation in the vessel being crossed or where bifurcations are present. Often times, tortuous sections or bifurcations in a vessel have severe angulations of up to 90 degrees or even greater, up to 180 degrees. Representative severe angulation points in the vasculature include the aortoiliac junction, the left subclavian artery bifurcation from the aorta, the brachiocephalic (innominate) artery bifurcation from the ascending aorta, as well as many other peripheral locations.

[0056] Referring again to FIG. 1, as described above, the catheter system 300 can include a spined aspiration catheter 320 having a flexible distal lumen 322 and a rigid proximal spine 330. The flexibility and lubricity of the lumen 322 mated to the rigid spine 330 as well as the outer diameter of the distal lumen 322 allow the spined aspiration catheter 320 to navigate to the site of an occlusion in the cerebral vessels as compared to other systems configured to navigate the cardiovascular system. The system described herein can reach emboli in regions of the anatomy that have long and tortuous access paths, which may include stenotic plaque material originating from the aortic arch vessels, carotid vessels and brachiocephalic vessels, which are at risk for embolic complications. Additionally, the cerebral vessels are typically more delicate and prone to perforation than the coronary arteries or other peripheral vasculature. The catheter system described herein has the ability to overcome these access challenges, making neurovascular intervention procedures easier to provide. The catheter systems described herein are designed to navigate bends rather than push through them. U.S. Patent Application Publication No. 2015 / 0174368, filed December 12, 2014, and U.S. Patent Application Publication No. 2015 / 0173782, filed December 19, 2014, which are incorporated herein by reference, describe features of catheter devices that can navigate the tortuous anatomy of the cerebral arteries.

[0057] The length of the distal lumen 322 can vary. In some embodiments, the length of the distal lumen 322 extends from a region near the distal tip of the access sheath body 222 to the site of the occlusion in the carotid artery, forming a proximal overlap region 120 with the distal end of the access sheath 222 (see FIG. 2B). To account for variability in the site of the occlusion and where the distal tip of the access sheath is located, the length of the distal lumen 322 can range from about 10 cm to about 25 cm. Because the length of the distal lumen 322 is less than the length of the sheath body 222 of the access sheath 220, the spined aspiration catheter 320 retracts into the sheath body 222, leaving a seal between the overlap region 328 of the spined aspiration catheter 320 and the inner diameter of the sheath body 222.

[0058] The catheter system herein may incorporate multiple spine catheters nested together to allow extended reach into tortuous anatomical structures. For example, a first spine catheter 320 having an outer diameter sized to be received within the lumen of the sheath body 222 may have a second spine catheter 320 extending through the inner lumen of the first spine catheter 320. The second spine catheter 320 may extend beyond the distal end of the first spine catheter 320 with its proximal spine so that the second spine catheter 320 having a smaller diameter can reach more distal regions of the vessel, particularly those regions of narrower dimensions. In this embodiment, the first spine catheter 320 serves as a support for the second spine catheter 320. The second spine catheter 320 has an internal lumen in fluid communication with the internal lumen of the first spine catheter 320, which is in fluid communication with and forms a continuous aspiration lumen with the internal lumen of the sheath body 222.

[0059] In one embodiment, the distal lumen 322 of the catheter 320 is configured to be soft and smooth for safe navigation to the target site, and kink and crush resistant for effective aspirating of clots when subjected to high suction forces, with multiple sections of increasing flexibility toward the distal end. In one embodiment, the distal lumen 322 includes three or more layers, including an inner lubricious liner, a reinforcing layer, and an outer jacket layer. The outer jacket layer may be constructed of discreet sections of polymer with different durometers, compositions, and / or thicknesses to vary flexibility along the length of the distal lumen 322. In one embodiment, the inner lubricious liner is a PTFE liner with one or more thickness sections along the different sections of flexibility. In one embodiment, the reinforcing layer is a generally tubular structure formed, for example, of a wound ribbon or wire coil or braid. The material of the reinforcing structure may be stainless steel, e.g., 304 stainless steel, nitinol, cobalt chrome alloy, or other metal alloy that provides the desired combination of strength, flexibility, and resistance to breakage. In one embodiment, the reinforcing structure may also include multiple materials and / or configurations to vary flexibility along the length of the distal lumen 322. In one embodiment, the exterior surface of the catheter 320 is coated with a lubricious coating, such as a hydrophilic coating. In some embodiments, there may be a coating on the interior and / or exterior surface to reduce friction during tracking. The coating may include a variety of materials known in the art. A coating may be formed on the spine to improve tracking through the access sheath 220. Suitable lubricious polymers are known in the art and may include hydrophilic polymers such as silicones, high density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxide, polyvinylpyrrolidone, polyvinyl alcohol, hydroxyalkyl cellulose derivatives, algins, sugars, caprolactone, and the like, and mixtures and combinations thereof. Hydrophilic polymers may be blended with each other or with blend amounts of water-insoluble compounds (including some polymers) to obtain coatings with suitable lubricity, adhesion, and solubility properties.

[0060] The outer diameter of the distal lumen 322 can be sized to allow navigation into the cerebral artery. It is desirable for the catheter to have an inner diameter as large as possible to allow safe navigation to the site of the occlusion to optimize suction. The appropriate size of the inner diameter can range between 0.040 inches and 0.075 inches, or between 0.040 inches and 0.088 inches, depending on the patient's anatomy and the clot and composition. The outer diameter should be as small as possible while still maintaining the mechanical integrity of the catheter 320. However, in the overlap region 120, the outer diameter (OD) of the catheter 320 approaches the inner diameter (ID) of the access sheath 220 to form a seal area in the overlap region 120 while allowing easy insertion of the catheter 320 through the sheath 220 and allowing placement of the catheter 320 at the desired site. In one embodiment, the catheter 320 and the access sheath 220 are sized to fit in the overlap region 120 without changing the outer diameter of the catheter 320 (see FIG. 2B). In one embodiment, the difference between the catheter OD and the access sheath ID at the overlap region is 0.002 inches or less. In another embodiment, the difference is 0.003 inches or less. In one embodiment, the catheter tapers toward the distal opening such that the most distal end of the catheter has a smaller outer diameter than the more proximal region of the catheter near where the catheter seals with the access sheath. In another embodiment, the catheter OD increases at the overlap region 328 to more closely match the inner diameter of the sheath (see FIG. 1). This embodiment is particularly useful in systems using multiple catheters adapted for use with a single access sheath size. It will be appreciated that if the catheter OD of the spine catheter 320 matches the sheath inner diameter or the difference is 0.002 inches or less, a seal against infused or aspirated fluids can be achieved by the overlap region 328 without the need to increase the catheter OD. Sealing against fluids injected or aspirated between the catheter and sheath can be achieved by the substantially same dimensional overlap of the catheter and sheath without incorporating a separate sealing structure or function.

[0061] In another embodiment shown in Figures 8A and 8B, there is a sealing element 336 disposed on the outer surface of the proximal end of the distal lumen 322. The sealing element 336 can be one or more external ridge features that can be compressed when the catheter 320 is inserted into the lumen of the access sheath 220. The ridge shape can be such that the sealing element 336 behaves as an O-ring, quad ring, or other piston seal structure. Figure 8B shows a similar configuration, where the sealing element 366 has a wiper seal configuration configured such that the angled surface is 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 coated braid structure, that can be inflated or expanded to provide a seal between the two devices at any time, even after the catheter 320 is positioned at the desired site. The advantage of this embodiment is that no sealing force acts on the catheter 320 during catheter positioning, but a sealing force is applied or acted upon to seal after the catheter 320 is positioned.

[0062] It is understood that the shape of the proximal end region of the distal lumen 322 may be an angled cut as opposed to the straight cut shown in Figures 8A-8B. It is understood that the spine 330 may be joined at the proximal end region of the catheter 320 and / or may extend along at least a portion of the distal lumen 322 such that the spine 330 is joined to the distal lumen 322 at a distance from the proximal end. The spine 330 and / or one or more elements that make up the section 322 may be joined to the section 322 using a variety of mechanisms including bonding, welding, gluing, clamping, stringing, tethering, or tying. In some embodiments, the spine 330 is joined to the lumen 322 by being clamped between layers of the distal lumen 322. For example, the spine 330 may be a hypotube or rod having a distal end that is ground, polished, or cut so that the distal end is laminated or otherwise attached to a layer of the catheter section 322 near the proximal end region. The area of ​​overlap between the spine 330 and the section 322 may be at least about 1 cm. This type of bond allows for a smooth, planar transition from the spine 330 to the lumen section 322.

[0063] In one embodiment, the overlap region is configured to be sealable against a vacuum of up to 25 inches of mercury (inHg), or up to 28 inches of mercury (inHg). In one embodiment, the overlap region 120 is configured to be sealable against a pressure of up to 300 mmHg, or up to 600 mmHg, or up to 700 mmHg with minimal leakage. Additionally, features may be provided to prevent the spine aspiration catheter 320 from advancing too far beyond the distal end of the access sheath 220. In some embodiments including an increased diameter and protruding features in the overlap region 328 of the spine catheter 320, the access sheath body 222 may have an undercut at its tip that prevents the proximal overlap of the spine aspiration catheter 320 from slipping out of the sheath body 222.

[0064] The distal lumen 322 of the catheter 320 may have a radiopaque marker 324 at its distal tip to aid in movement and proper positioning of the distal tip under fluoroscope (see FIG. 1). Additionally, the proximal overlap region 328 of the catheter 320 may include one or more proximal radiopaque markers 1324 so that the overlap region 120 may be visualized as a relationship between the access sheath distal marker 224 and the catheter proximal marker 1324 (see FIG. 12C). In one embodiment, the two markers (the distal tip marker 324 and the more proximal marker 1324) are distinct to minimize obscuration in fluoroscopic images, for example, the catheter proximal marker 1324 may be a single band and the sheath tip marker 224 may be a double band.

[0065] The spine 330 of the spined aspiration catheter 320 is coupled to the proximal end region of the distal lumen 322. The spine 330 is configured to allow the catheter 320 to be advanced distally and retracted proximally through the lumen 223 of the access sheath 220. In one embodiment, the length of the spine 330 is greater than the overall length of the access sheath 220 (from the distal tip to the proximal valve), for example, about 5 cm to 15 cm. As shown in FIG. 1, the spine 330 can include a mark 332 indicating the overlap between the distal lumen 322 of the catheter 320 and the sheath body 222. The mark 332 can be positioned such that when the mark 332 is aligned with the sheath proximal valve 234 during insertion of the catheter 320 through the sheath 220, the spined catheter can be positioned in a distal-most position with the minimum overlap length required to form a seal between the spined aspiration catheter 320 and the access sheath 220. The spine 330 can include a gripping feature, such as a tab 334, on the proximal end to allow for easy grasping and advancement or retraction of the spine. The tab 334 can be coupled to one or more elements of the system 300, such as a dilator configured to extend through the lumen 323 of the distal lumen 322, as described in more detail below. The proximal tab 334 can be configured to allow for easy differentiation among other devices present within the sheath proximal valve 234, such as a guidewire 270 or a retrievable stent device wire 500. In one embodiment, the spine 330 is brightly colored or marked to allow for easy differentiation from guidewires, retrievable stent tethers, and the like.

[0066] The spine 330 is configured to be sufficiently rigid to allow for advancement and retraction of the distal lumen 322 of the spined aspiration catheter 320, yet flexible enough to navigate through the brain anatomy as needed. Additionally, the outer diameter of the spine 330 is sized so as not to take up too much luminal area within the lumen 223 of the access sheath 220 and sheath body 222. In one embodiment, the spine 330 is a round wire measuring 0.014 inches to 0.018 inches. In another embodiment, the spine 330 is a ribbon measuring 0.010 inches to 0.015 inches in thickness and 0.015 inches to 0.025 inches in 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, as well as a plastic, such as various polymers.

[0067] One or more elements of the systems described herein can be made from metals, metal alloys, polymers, metal-polymer composites, ceramics, combinations thereof, or other suitable materials. Some examples of suitable metals and metal alloys include: stainless steels, such as 304V, 304L, and 316LV; mild steel; nickel-titanium alloys, such as linear elastic and / or superelastic Nitinol; other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625, such as INCONEL® 625; UNS: N06022, such as HASTELLOY® C-22®; HASTELLOY® C276®; and the like). Nickel-copper alloys (e.g., UNS:N04400, such as MONTEL 400, NICKELVAC 400, NICORROS 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N), nickel-molybdenum alloys (e.g., HASTELLOY, ALLOY B2®, other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten alloys or tungsten alloys, etc.; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003, such as ELGILOY®, PHYNOX®, etc.); platinum-rich stainless steels; titanium; combinations thereof, etc.; or other suitable materials.

[0068] The junction between the distal lumen 322 of the catheter 320 and the proximal spine 330 is configured to allow a smooth transition in flexibility between the two sections without forming kinks or weak points, and to allow smooth passage of devices such as guidewires and microcatheters through the continuous internal lumen formed by the lumen 223 of the access sheath 220 and the lumen 323 of the catheter 320. In one embodiment, the distal lumen 322 has a transition 326 (see FIG. 1 ) near where the distal lumen 322 joins the spine 330, which has an angled cut, so that there is no abrupt, gradual transition from the internal lumen 223 of the sheath 220 to the internal lumen 323 of the catheter 320. The angled cut can be generally planar. In another embodiment, the angled cut can be curved or stepped to provide a more gradual transition area. The distal lumen 322 and the spine 330 can be joined by a welded bond, a mechanical bond, an adhesive bond, or a combination thereof. The distal end of the spine 330 can have features such as a textured surface, a protruding feature, or a cut-out feature to facilitate mechanical bonding during welding. During the heat welding process, the feature promotes mechanical bonding between the polymeric distal lumen 322 and the spine 330. In another embodiment, the catheter system 1300 shown in FIGS. 12A-12B having a spined catheter 1320 and a dilator 1340 extending therethrough forms a smooth transition in flexibility between the two portions upon advancement of the system 1300 without kinking or forming weak points. Removal of the dilator 1340 from the spined catheter 1320 can result in loss of this smooth transition in flexibility. The spined catheter 1320 can be withdrawn first if the risk of forming kinks or weak points can be significantly reduced.

[0069] Because the spined aspiration catheter 320 does not have a lumen that extends its entire length 320 due to the presence of the spine 330 on its proximal end region, traditional flushing or preparation steps are ineffective if the lumen of the catheter becomes clogged, either before use or during a procedure. In traditional single lumen catheters, a syringe is attached to the proximal adapter of the catheter, and the internal lumen is forcefully flushed with a solution. The spined catheter 320 may also be provided with an attached catheter flushing and cleaning device 350 (see FIG. 1). This device 350 may be a tube with a blunt or tapered tip at the distal end and a female Luer connector at the proximal end. The Luer connector may connect a syringe to the device 350. The blunt or tapered tip allows the device 350 to be inserted into either the distal or proximal end of the lumen 322 of the catheter 320 without risk of damaging the catheter 320, and the syringe may be operated to flush the device. The OD of the clearing device 350 closely matches the ID of the lumen 322 of the spine catheter 320, allowing it to flush the spine aspiration catheter 320 with sufficient force to clear debris and aspirated occlusive material from the catheter. The device 350 can be used to mechanically clear clots with a plunger type action, and the working length of the device 350 can be at least as long as the distal lumen 322 of the catheter 320, allowing it to be inserted through the entire lumen 323 of the distal lumen 322. Flush may be used in conjunction with pushing the device to more effectively remove clots or other embolic material from the catheter 320.

[0070] In another embodiment, the aspiration catheter 320 is a single lumen catheter, for example, catheters of that type are described in co-pending U.S. Patent Application Publication No. 2015 / 0174368, filed December 12, 2014. In that embodiment, the catheter may be provided with or coupled to a tapered coaxial dilator that is generally cylindrical and has a tapered distal portion that allows for a smooth transition between the catheter and a guidewire disposed within the catheter.

[0071] The spined aspiration catheter 320 can be moved through the blood vessel over an appropriately sized microcatheter and guidewire. Alternatively, the spined catheter 320 can be supplied with a coaxial dilator 340 (see FIG. 1). The dilator 340 is sized and shaped to be inserted in a coaxial manner through the inner lumen 323 of the distal lumen 322 of the catheter 320 such that, in use, the proximal end region of the dilator 340 is aligned alongside the spine 330 of the catheter 320. The dilator 340 can have a tapered distal tip 346. The length of the dilator 340 can be at least as long as the spined aspiration catheter 320, such that at a minimum, the distal tapered tip 346 protrudes beyond the distal end of the lumen 322 of the spined catheter 320. The dilator 340 can have an outer diameter that provides a smooth transition to the distal end of the catheter and a distal tapered tip 346 that provides a smooth transition from the inner lumen of the dilator 340 to the guidewire that extends outwardly. The dilator 340 can be generally cylindrical along at least a portion of its length. In one embodiment, the tapered dilator 340 is designed to accept a guidewire having a diameter in the range of, for example, 0.014 inches and 0.018 inches. In this embodiment, the diameter of the inner lumen can be between 0.020 inches and 0.024 inches. The tapered distal tip 346 can be in the range of 1.5 cm to 3 cm.

[0072] It should be understood that the dilators described herein for use with spined catheters may vary in configuration. For example, as described above, the dilator 340 may be a coaxial dilator 340 that is generally cylindrical and has a tapered distal portion that allows for a smooth transition between the catheter 320 and a guidewire disposed within the catheter 320. The cylindrical body of the dilator 340 may extend along the entire length of the catheter 320. Alternatively, the dilator 340 may incorporate a proximal spine that is aligned alongside the spine of the catheter 320. The proximal spine may be positioned coaxially with or eccentrically relative to the distal end region of the dilator 340. The coaxial proximal spine of the dilator 340 may have a lumen extending therethrough. Alternatively, the dilator 340 may be a solid rod without a lumen. A solid rod dilator can be made from a malleable material that is milled to have a narrow outer diameter (e.g., 0.010 inch to 0.014 inch) so that the dilator can be molded to any angle and shape desired by the user, similar to how a guidewire is used. In this configuration, the catheter system does not include a guidewire or microcatheter. Such a dilator has an advantage over a microcatheter in that it has an outer diameter that is 0.003 inch to 0.010 inch smaller than the inner diameter of the spine catheter 320.

[0073] The dilator 340 may have a proximal female luer adapter 348 at its proximal end to allow the dilator 340 to be flushed with a syringe. The dilator 340 may incorporate a clip feature at its proximal end to allow the dilator 340 to be made of a sufficiently flexible material and the tapered distal tip 346 to be of sufficient length to allow a smooth transition between the flexibility of the guidewire and the flexibility of the catheter. This configuration allows the catheter 320 to be easily advanced through tortuous anatomy into the target cerebral vessel. In one embodiment, the distal end of the dilator 340 has a radiopaque marker 344 and / or marker 343 at the proximal end of the tapered distal tip 346. The marker material may be a platinum / iridium band, a polymer impregnated with tungsten, platinum or tantalum, or other radiopaque marker.

[0074] The dilator 340 can be configured to vary in stiffness between the distal and proximal ends of the dilator 340. For example, the most distal portion, which extends beyond the distal end of the lumen 322 of the catheter 320, can be made of a softer material, with progressively stiffer materials being used toward the more proximal portion. In some embodiments, as described in more detail below, the dilator 340 can be a spined dilator having a proximal spine. The proximal end of the dilator 340 can include a tab 1364 that can lock the dilator 340 with a tab 334 on the proximal end of the spine 330 of the catheter 320, allowing the two elements (spine catheter 320 and dilator 340) to be advanced along a 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 insertable through a central opening of the tab 334 such that the ring of the tab 334 is received in the annular detent of the tab 1364 to form a single gripping element by which a user can advance and / or retract the catheter system through the access sheath. The tab 1364 can be attached to the dilator 340 or can be slidable on the dilator 340 to accommodate different relative positions between the dilator 340 and the spined catheter 320.

[0075] 12A-12B provide additional views of the spined aspiration catheter and dilator system 1300 described elsewhere herein. FIGS. 12A-12B show a spined aspiration catheter 1320 having a dilator 1340 extending through an aspiration lumen 1323 of a distal lumen 1322. As described elsewhere herein, the catheter 1320 can have a proximal spine 1330 having a tab 1334 and a distal lumen 1322 having an aspiration lumen 1323. The spine 1330 can extend between the distal lumen 1322 and the tab 1334. The dilator 1340 is receivable within the aspiration lumen 1323 of the spined catheter 1320. The dilator 1340 can include a distal dilator 1360 and a proximal spine 1362. The dilator 1360 can extend between the distal tip 1346 of the dilator 1340 and the beginning of the proximal spine 1362. When engaged with the catheter 1320, the dilator 1340's dilator 1360 can extend through the entire length of the distal lumen 1322 of the catheter 1320 such that the dilator tip 1346 extends a predetermined distance beyond the distal end of the distal lumen 1322 of the catheter 1320 to provide a smooth transition for improved tracking. As described elsewhere herein, the dilator tip 1346 can be tapered and can be soft, atraumatic, and pliable to the vessel wall, thereby facilitating intravascular navigation to emboli in tortuous anatomical structures compared to dilators typically used for percutaneous arterial access, which dissect blithely through tissue and arterial walls.

[0076] The dilator 1340 is shown in a locked configuration with the catheter 1320 configured for improved tracking through tortuous and often diseased vessels in acute ischemic stroke. The dilator section 1360 can include one or more detents on an outer surface of the dilator section 1360. The detents can be located near the proximal end region and / or the distal end region of the dilator section 1360. The detents are configured to lock to correspondingly shaped surface features on the inner surface of the lumen 1323 through which the dilator section 1360 extends. The dilator 1340 can include an extension tab 1364 at the proximal end of the proximal spine 1362 of the dilator 1340, which can be configured to connect and lock to corresponding features on the proximal end region of the catheter spine 1330, as described above, for example, via one or more detents or other surface features. This allows the dilator 1340 and the catheter 1320 to have more than a single locking connection point between them. The proximal spine 1362 of the dilator 1340 can extend between the dilator section 1360 and the tab 1364 of the dilator 1340. The dilator section 1360 is a tubular element, as described elsewhere herein, that defines a guidewire lumen that runs the entire length of the dilator section 1360 (and the entire length of the distal lumen 1322 of the spined catheter 1320). It should be understood that the entire dilator 1340 can be a tubular element configured to receive a guidewire through the dilator section 1360 as well as the spine 1362. The proximal end of the dilator section 1360, i.e., the transition 1326 between the dilator section 1360 and the proximal spine 1362, can include a "step up" to smooth the transition between the distal lumen 1322 of the catheter 1320 and the dilator section 1360 of the dilator 1340. The transition 1326 can incorporate an angled cut so that there is no abrupt, gradual transition from the inner lumen 1223 of the sheath 1220 to the inner lumen 1323 of the catheter 1320, thereby allowing the spined aspiration catheter-dilator 1300 to be smooth against the vessel wall it contacts.

[0077] The proximal spine 1362 of the dilator 1340 can have similar stiffness and properties as the spine 1330 of the catheter 1320. More specifically, one or both of the spines 1362, 1330 can have stiffness and / or kink resistance. Additionally, one or both of the spines 1362, 1330 can have a stiffness that allows for pushing the multiple distal portions, i.e., the combined distal lumen 1322 and dilator portion 1360, through an access sheath or guidewire while producing a very low profile.

[0078] The catheter tab 1334 and the dilator tab 1364 can be removably connected to one another. More specifically, the tabs 1334, 1364 can have a locked and an unlocked configuration. In the locked configuration, the dilator tab 1364 can engage with the catheter tab 1334. In the unlocked configuration, the dilator tab 1364 can disengage from the catheter tab 1334. The dilator tab 1364 can be attached, for example, by clicking or locking, to the catheter tab 1334 in a manner that maintains the relationship between the corresponding portion of the spined dilator 1340 and the spined catheter 1320 in the locked configuration. Such locking can be achieved, for example, by using a detent on the dilator tab 1364 to snap into place within a recess formed in the catheter tab 1334. In some embodiments, the spine 1330 of the spined catheter 1320 can move alongside or within a special channel in the dilator spine 1362. The channel can be disposed along the length of the dilator spine 1362 and can have a cross-sectional shape that matches the cross-sectional shape of the catheter spine 1330 such that the spine 1330 of the catheter 1320 can be received within the channel and slide smoothly bidirectionally along the channel. Once the spined catheter 1320 and spined dilator 1340 are secured, the combined system, i.e., aspiration catheter-dilator 1300, can be delivered to the target site, for example, through the lumen 223 of the access sheath 220 described elsewhere herein.

[0079] 12B, a spined aspiration catheter-dilator 1300 is shown having a spined catheter 1320 and a spined dilator 1340 in an unlocked configuration according to one embodiment. Once the spined aspiration catheter-dilator 1300 is positioned at the target site, the dilator tabs 1364 can be unlocked by the catheter tabs 1334, as described herein. The spined dilator 1340 can be withdrawn and the spined catheter 1320 can be used, for example, for aspiration or over-the-wire or balloon delivery.

[0080] FIG. 13 is a cross-sectional view of a spined catheter 1320 coaxially positioned with a spined dilator 1340, taken along line AA in FIG. 12B, according to one embodiment. The cross-sectional view shows a catheter-dilator portion with a dilator 1360 received within an aspiration lumen 1323 of a distal lumen 1322. The lumen 1323 may have an inner diameter ranging up to 0.072 inches, although larger or smaller inner diameters are possible. The wall of the distal lumen 1322 may resist twisting or ovalization to provide a maximum diameter for aspiration. The dilator portion 1360 may be received in the distal lumen 1322 with a slip fit. Thus, in one embodiment, the outer diameter of the dilator portion 1360 may be less than the inner diameter of the distal lumen 1322. For example, the lumen 1323 may have a diameter of 0.072 inches and the dilator portion 1360 may have an outer diameter of 0.070 inches.

[0081] Figure 14 is a cross-sectional view of the spined catheter 1320 without the spined dilator 1340 taken along line BB in Figure 12B according to one embodiment. The cross section shows the distal lumen 1322 after the dilator 1360 has been retracted and / or removed. The distal lumen 1322 has an inner wall 1321 that defines a lumen 1323. The lumen 1323 may be circular as shown, or may be another shape. In one embodiment, the effective diameter of the lumen 1323 ranges up to 0.072 inches.

[0082] FIG. 15A illustrates a spined aspiration catheter-dilator system 1300 having a spined catheter 1320 and a spined dilator 1340 in a locked configuration, according to one embodiment. In one embodiment, the spine 1330 and dilator 1340 can have substantially similar overall dimensions along their entire length. For example, rather than converging to a smaller dimension between the dilator section 1360 and the dilator spine 1362, the dilator spine 1362 can have the same dimensions as the dilator section 1360, thus providing a catheter-dilator having substantially the same cross-sectional area along at least a majority of its length. As discussed above, the spined dilator 1340 and the spined catheter 1320 can have corresponding tabs 1334, 1364 that engage in the locked configuration and disengage in the unlocked configuration.

[0083] FIG. 15B illustrates a spined aspiration catheter-dilator with the spined catheter 1320 and the spined dilator 1340 in an unlocked configuration, according to one embodiment. The spined dilator 1340 can be removed from the spined catheter 1320 in a manner similar to that described above. In one embodiment, the spined aspiration catheter-dilator can have a similar cross-sectional area over the majority of its length, such that the shapes of the spined catheter 1320 and the spined dilator 1340 can be complementary. For example, the spine 1330 can have a cross-sectional area along an arc of a circle, e.g., a quadrant, such that the cross-sectional area of ​​the dilator spine 1362 can be three-quarters of a circle. In this manner, the spine 1330 can match the dilator spine 1362 to provide a full cross-sectional area of ​​a full circle.

[0084] 16 is a schematic diagram of a spined catheter 1320 having a distal lumen 1322 with an internal lumen 1322 located within the neurovascular anatomy, according to one embodiment. When used with an access sheath 1220 having a sheath body 1222 and an internal lumen 1232, it will be appreciated that the overlap region 1120 forms a seal with the access sheath 1220, with the distal lumen 1322 being 25 cm in length in one embodiment where the spined catheter 1320 reaches the ICA and is consistently felt to be less than 20 cm away from the embolus E. The overlap region can be several centimeters in length and can vary depending on the distance of the distal end of the distal lumen of the lumen 1322 from the embolus E, for example, depending on how far the spined catheter 1320 is advanced from the access sheath 1220.

[0085] As described elsewhere herein, the luminal area available for aspiration of emboli is greater with the spined catheter 1320 than with an aspiration system having a conventional large bore catheter in the access sheath. More specifically, the combined volume of the luminal area of ​​the spined catheter 1320 and the luminal area of ​​the access sheath 1220 near the distal lumen 1322 is greater than the luminal area of ​​a large bore catheter along the entire length of the system, thereby increasing the likelihood of removing an emboli in a single aspiration attempt. More specifically, the enlarged luminal diameter along the spine 1330 allows for greater aspiration forces to be obtained, improving aspiration of the emboli. The enlarged luminal diameter can also increase the annular area over which a device, such as a microcatheter or tapered inner member, can be forward-washed with contrast, saline, or other solutions while coaxially positioned in the spined catheter and access sheath. This can improve the ease and ability to perform angiograms during device movement.

[0086] The disclosed systems may include auxiliary devices that are specifically configured for use with the systems. It is understood that reference to one embodiment of an access sheath system or aspiration catheter system is not intended to be limiting, and that the auxiliary devices described herein may be used with any system having variations or combinations of the features described herein. For example, where an access sheath is described below, it is understood that it may incorporate one or more features of any of the access sheaths or access sheath systems described herein. Similarly, where a spined catheter is described below, it may incorporate a spined catheter or spined catheter system described herein.

[0087] In one embodiment, the system includes a microcatheter 400 (see FIG. 1). The microcatheter 400 can be configured to be particularly suitable for navigation within the cerebral vasculature. A microcatheter 400 can be used in place of the tapered dilator 340 to aid in moving the spine catheter 320 to the desired site. Thus, at its proximal end, it may include a means for locking the spine 330 to the microcatheter 400, so that the two elements (spine catheter and microcatheter 400) can be advanced as a single unit along a guidewire. In some instances, the microcatheter 400 is advanced in front of the catheter 320 to provide support as the catheter 320 advances, or to cross the occlusion and perform an angiogram distal to the occlusion. In this case, the length of the microcatheter 400 can be approximately 10-20 cm longer than the spine catheter. 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 delivery of the retrievable stent device 500, for example, in the range of 0.021 inches and 0.027 inches, and an inner liner of PTFE. The microcatheter 400 may be at least about 5-10 cm, or alternatively about 5-20 cm, longer than the overall length of the spine catheter 320 so that it can extend beyond the distal end of the aspiration catheter 320 during movement.

[0088] In one embodiment, the system includes a retrievable stent device 500 having a distal expandable portion 510, which is sized and configured for delivery through a microcatheter 400, as shown in FIG. 9. The retrievable stent device 500 can be used with other elements of the system to aid in the removal of an obstruction. The retrievable stent device 500 can also be used to rapidly restore flow to an obstructed artery during a thrombectomy procedure. Examples of retrievable stent devices include the Solitaire Revascularization Device (Medtronic) or the Trevo Stentriever (strayker).

[0089] In a method of use, the retrievable stent device 500 is used to assist in entrapment of thrombus into the catheter 320 during the aspiration phase or to assist in clearing the catheter 320 that may become clogged during the aspiration phase. In one embodiment, the retrievable stent device 500 is configured to be particularly adapted to perform these functions. For example, as shown in FIG. 10A, the distal end of the expandable portion 510 of the device 500 has multiple struts or elements that come together at the distal end to close off the most distal end, thereby allowing blood flow across the device, but is configured to capture thrombus debris as the device 500 is retracted into the catheter 320 and then exit the distal end through the catheter 320. Alternatively, the distal end 520 is a filter element or a balloon element.

[0090] In another example shown in Figure 10B, the retrievable stent device 500 includes two or more segments, with one or more proximal segments 510a configured to be expandable within the distal inner lumen of the catheter, while one or more distal segments 510b are configured to be expandable across the occlusion, as is done with conventional retrievable stent devices. Alternatively, as seen in Figure 10C, the retrievable stent device 500 has a very long expandable portion 510, with a proximal portion of the expandable portion expandable within the distal inner lumen of the catheter, while a distal portion is expanded across the occlusion. In all of these embodiments, the proximal end of the expandable portion 510 has minimal structural elements, which allows the expandable portion to be easily retracted into the lumen of the catheter 320 and out of the access sheath 320, minimizing the impediment to thrombus aspiration through the device. In these embodiments, even if a clot is aspirated into the catheter 320, the expandable portion 510 still engages the clot, and if the catheter 320 becomes plugged, the device 500 is in a good position to clear the clot when pulled back. Once the retrievable stent device 500 is removed from the lumen 322 of the catheter 320, additional suction can be applied to the site through the catheter 320 if it is still partially or completely blocked. If the catheter 320 remains blocked, this step is not possible, so the catheter must be removed and flushed outside the patient's body before being reinserted for additional suction. This configuration of the retrievable stent device 500 can be used with either a traditional single lumen aspiration catheter or a spined aspiration catheter 320.

[0091] The embodiment of device 500 shown in Figures 10A-10C can be used in conjunction with known thrombectomy devices and methods that address the problem of catheter clogging during thrombus aspiration.

[0092] In one embodiment, as shown in FIG. 2A or FIG. 3, the system includes a suction source 600. The suction source 600 can be attached to the suction line 230 on the access sheath 220. Examples of the suction source 600 can 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 separate, a mechanical or electromechanical fluid pump whose outlet is connected to a blood collection reservoir, or integrated into a single device such as a syringe or syringe pump. Alternatively, the blood collection reservoir is connected to a vacuum source such as a hospital vacuum line or an air vacuum pump, thus providing the container as well as the suction source. A filter and / or a check valve can be coupled 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 pumping mechanisms known in the art.

[0093] In one embodiment, the suction source is a variable or multi-state suction source and includes a mechanism for controlling the suction level, including, for example, changing the vacuum level in a vacuum pump, changing the power to a motor of a positive displacement, peristaltic or centrifugal pump, or changing the syringe retraction speed in a syringe or syringe pump. Alternatively, the suction speed can be varied by providing an element with variable flow resistance, such as a parallel flow path that can be switched between high and low flow resistance paths, an orifice or lumen that can be variably opened, or other means by which flow resistance can be varied. In one example, the suction source is configured to have two levels of suction: a high level of suction used when the catheter is in contact with thrombotic material to aspirate the thrombotic occlusion, and a low level of suction used during steps where there is a high risk of causing distal embolism, such as when a lesion is crossed or a retrievable stent device is expanded and flow is restored to the vessel.

[0094] In another example shown in FIG. 11, the suction source 600 further includes a flow sensor 275 that senses the flow rate in the suction line 230, which is coupled to a controller that controls the level of suction. The suction source 600 can increase the suction level when the flow rate is slow and decrease the suction level when the flow rate is increased. In this way, the force is greatest when the catheter is clogged or partially clogged, but is reduced to a minimum level when limiting the volume of blood aspirated while ensuring free flow to ensure protection from distal emboli. In this way, the system optimizes the aspiration of clots while limiting the amount of blood aspirated. Alternatively, the suction source 600 can include a vacuum gauge. When the flow in the catheter 320 is blocked or restricted, the pump generates a higher level of vacuum. In this example, the suction force can be configured to increase when a higher vacuum is detected.

[0095] In yet another embodiment of the suction source, the suction source 600 provides a periodic level of suction, for example, cycling between high and low levels of vacuum, or high and no vacuum, or high and low vacuum, at a predetermined frequency. The periodic suction mode can provide a jackhammer type force to the clot, enhancing the ability to aspirate the clot through the catheter. Periodic suction can be enabled via solenoid valves, programmable pump motors, and the like. In one embodiment, periodic suction is applied at low flow rates or high vacuum, as described above, only when a clog or restricted flow is detected in the aspiration line, and at other times the suction source reverts to low flow or is turned off. This configuration can be user controlled or configured to be automatically controlled via a feedback loop to the suction source.

[0096] In one embodiment, the system includes an automatic reflux mechanism configured to connect 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 to an external reservoir set at zero or negative pressure.

[0097] In one embodiment shown in FIG. 11, the irrigation line 236 may be connected to a syringe 286 holding saline or a radiopaque contrast agent via a stopcock 238. Additionally, the irrigation line 236 may be connected to an irrigation source 288, for example, a pressurized bag of saline. A valve 292 may control the flow from the irrigation source 288 to the irrigation line 236. When the valve 292 is open to the irrigation line 236, a pressurized source of fluid is provided. In one embodiment, the valve 292 is coupled to the suction source 600 via a mechanical or electromechanical coupler 295 such that the valve 292 is open only when the suction source 600 is on. Alternatively, the valve 292 is coupled to a flow sensor 275 in the suction line 230 such that the valve 292 is on only when there is flow toward the suction source 600. In these embodiments, the flow rate of the irrigation source 288 is high enough to clear the blood in the proximal extension 240, but not so high as to create a flow that acts against the aspiration flow and limits the aspiration of clots. The advantage of this embodiment is that the blood remains clear in the proximal extension 240, and any emboli or air within the proximal extension 240 are clearly visible. This provides feedback to the user when flushing the catheter with saline or contrast via syringe 286.

[0098] In another embodiment, valve 292 is either mechanically or electromechanically connected to valve 242, which connects sheath body 222 to proximal portion 240 of sheath 220. Coupling 290 can be configured such that valve 292 is open only when valve 242 is closed. This feature allows blood to be removed from proximal extension 240 via a flushing step without risking emboli back through the catheter and into the vasculature. Coupling 290 can be configured, for example, in any of a number of ways. For example, coupling 290 can always be open when valve 242 is closed, or valve 238 can be prevented from opening unless valve 242 is closed and automatically opens.

[0099] In one embodiment, valve 292 is a variable-acting valve that allows for different levels of irrigation flow rates. In this example, valve 292 is configured for slow irrigation when the suction source is at a low setting and for a high level of irrigation when the suction source is at a high setting. In one embodiment, valve 292 is configured for an even higher level of irrigation when valve 242 is closed. These configurations allow for continuous removal of debris and / or clear visibility of the proximal portion of the access sheath while minimizing the risk of distal emboli or air entering the vessel during steps of the procedure. For example, in the step where the distal tip of the catheter is removed from proximal hemostasis valve 234, any clots trapped at the tip of the catheter are liberated as the catheter is pulled through the valve, but the liberated emboli are washed into the aspiration line by continuous irrigation and do not remain in the sheath where they may be reinjected into the vessel, for example, during contrast injection after the catheter is removed.

[0100] Referring again to FIG. 1, the system 100 may include a kit of multiple devices. In one embodiment, the kit includes an access sheath system 200, which 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 spined catheter systems 300 having one or more inner diameters. In one embodiment, the spined catheter system 300 includes a spined aspiration catheter 320 and a tapered dilator 340. In one embodiment, the spined catheter system 300 also includes a catheter clearing tool 350. In yet another embodiment, the system 100 includes an access sheath system 200, a tapered catheter system 300, a microcatheter 400, and a retrievable stent device 500.

[0101] In an embodiment configured for percutaneous access, the kit includes an access sheath 220, with an insertable sheath body 222 having a length of about 23 cm, a proximal extension 240 having a length of about 22 cm, a connector 226 having a length of about 7 cm, a proximal hemostatic valve 234 having a length of about 5 cm, and an overall length of the access sheath having a length of about 57 cm. In one embodiment, the kit also includes a spined aspiration catheter 320, with a catheter distal lumen 322 having a length of about 20 cm, a transition section 326 having a length of about 2-4 cm, and a spine section 330 having a length of about 65 cm, and an overall length of the spined catheter having a length of about 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 about 198 cm and a retrievable stenting device 500 having a total length of 128 cm.

[0102] In an embodiment configured for transfemoral access, the kit includes an access sheath system 220, with an insertable sheath body 222 having a length of about 90 cm, a proximal extension 240 having a length of about 22 cm, a connector 226 having a length of about 7 cm, a proximal hemostatic valve 234 having a length of about 5 cm, and an overall length of the access sheath 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 a spined aspiration catheter 320, with a catheter distal lumen 322 having a length of about 20 cm, a transition section 326 having a length of about 2-4 cm, a spine section 330 having a length of about 132 cm, and an overall length of the catheter 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.

[0103] In another embodiment, the kit includes the access sheath 220 having a detachable 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 appropriate for the procedure. In this embodiment, the kit can include a spined aspiration catheter 320 or a single lumen aspiration catheter.

[0104] In any of these embodiments, the kits can 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 kits can include a means for automatic cleaning, such as coupling means 290 or 292.

[0105] As described elsewhere herein, it is understood that references to one embodiment of an access sheath system or catheter system are not intended to be limiting, and that the kits described herein can incorporate any of the systems and / or auxiliary devices described herein having any of a variety of features. For example, when an access sheath is described as part of a kit, it is understood that it can incorporate one or more features of any of the access sheaths or access sheath systems described herein. Similarly, when a spined catheter is described as part of a kit, it is understood that it can incorporate one or more features of any of the spined catheters or spined catheter systems described herein.

[0106] 2A and 3 show the method of use. As shown in FIG. 2A, the access sheath 220 is inserted into the femoral artery using a standard vascular access sheath and advanced until the sheath tip is located as far distal as safely possible within the internal or common carotid artery. In FIG. 3, the access sheath 220 is inserted directly into the common carotid artery and advanced until the sheath tip is located as far distal as safely possible within the internal carotid artery. In either scenario, the sheath is first advanced into the common or proximal carotid artery, and then a dilator is advanced and exchanged for a softer dilator before advancing the sheath more distally into the internal carotid artery. The sheath is then secured to the patient using sutures through the eyelets of the sheath connector. The sheath is then secured to the patient using sutures through eyelets on the sheath connector. The sheath aspiration line 230 is connected to an aspiration source 600, such as a syringe or aspiration pump. The sheath aspiration line may be connected to a forward flush line (such as a pressurized saline bag) via a stopcock or a stopcock manifold.

[0107] Once the sheath tip is secured in the desired location, it is secured to the patient. The spined catheter, tapered dilator, and guidewire are pre-assembled in a coaxial configuration and introduced into the carotid artery through the sheath proximal hemostatic valve. The spined aspiration catheter 320 is advanced through the access sheath and positioned once 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 aspect of the occlusion. The mark 332 on the spine 330 ensures that there is still an overlap region 120 between the distal lumen 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 in place of the tapered dilator 340 to assist in moving the catheter 320 into the occlusion. During this procedure, forward flushing is opened to the aspiration lumen to keep the lumen clear before or during aspiration. At any point during device movement, suction can be initiated from suction source 600 at a level appropriate for distal embolic protection, for example, when the guidewire or microcatheter 400 is crossing the occlusion.

[0108] Once the distal tip of the spined aspiration catheter 320 reaches the surface of the clot, suction is initiated at a level appropriate for aspiration thrombectomy, which is a higher level than distal embolic protection. The catheter 320 can remain in aspiration mode on the clot for any period of time the user deems appropriate. Depending on the outcome of the aspiration thrombectomy procedure (by observing the flow through the aspiration line and / or resistance to rearward force on the catheter spine), 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 situ, or the catheter 320 can be slowly retracted into the sheath 220. If blood flow is restored to the artery by aspirating the clot through the catheter 320 and sheath 220, a final angiogram can be performed and the catheter 320 can be retracted. However, if a thrombus occludes the catheter tip and cannot be removed, the suction force causes the catheter 320 to be pulled back with some or all of the occlusion attached to the tip of the catheter 320.

[0109] In the latter scenario, suction is maintained at the tip of the catheter 320 throughout the entire time the catheter 320 is retracted into the access sheath 220. Once the catheter 320 is fully retracted into the access sheath, the catheter 320 can be quickly removed from the sheath body 222 while maintaining suction in the sheath. It should be appreciated that the catheter 320 may be retracted into the sheath body 222 after extending through a distal opening 219 at the distal tip of the sheath body 222. Alternatively, the catheter 320 may extend through a side opening 219 near the distal end region of the sheath body 222, in which case the catheter 320 is retracted through this side opening 219 into the sheath body 222. At some point during catheter retraction, the suction level may be changed from a high level suitable for suction thrombectomy to a low level suitable for distal embolic protection, depending on whether the catheter 320 is clogged with occlusive material. By providing the ability to continuously maintain suction from either the catheter tip or the sheath tip or the sheath distal region, and by providing a means to maintain suction with varying suction levels, this procedure can optimize the ability to suction while minimizing distal embolism and while minimizing blood loss from suction. If desired, suction can also be initiated on the flush line 236 of the proximal valve 234, thereby reducing the likelihood of distal embolism upon removal of the catheter tip, which may have clots attached, through the proximal valve 234.

[0110] The spined aspiration catheter 320 can be completely removed from the proximal hemostatic valve 234 of the sheath 220. Alternatively, if the access sheath 220 has a proximal extension 240, the distal lumen 322 can be retracted into the proximal extension 240. In the latter scenario, once retracted, the catheter 320 and sheath 220 can be flushed to remove potential embolic material without completely removing the catheter 320 from the sheath 220. Vigorous flushing from the proximal valve flush line 236 along with suction from the aspiration line 230 creates a clean environment for the catheter 320 and sheath 220. If desired, a catheter cleaning tool 350 can be inserted into the sheath proximal valve 234 and used to clear the lumen 323 of the catheter 320 at this point. If the access sheath 220 has a connector valve 242, the proximal portion 240 may be closed off from the sheath body 222 at this stage, thereby preventing the risk of embolic material entering the sheath body 222 and into the artery.

[0111] Alternatively, the valve 242 can be closed to stop suction while the proximal valve is opened or removed, and the catheter 320 is completely removed from the sheath 320. Closing the valve 242 limits blood loss from the sheath when the catheter 320 is removed. The catheter 320 may then be washed over the table using the cleaning tool 350 or flushed into a bowl or other receptacle. The proximal extension 240 may be washed using a flush source 288 from the proximal valve flush line 236, simultaneously with suction from the suction line 230, or by opening a side port for washing over the table or flushing into a bowl or other receptacle. If desired, an angiogram can be performed to evaluate flow through the treated artery. If the procedure indicates, the catheter 320 or other catheter can be advanced again over the guidewire and tapered dilator 340 or microcatheter 400 as described above to attempt another suction thrombectomy step. Flush of the catheter and proximal extension 240 of the access sheath 220 can minimize the risk of distal embolism during these subsequent steps.

[0112] In another exemplary method, the retrievable stent device 500 can be used in conjunction with aspiration to remove a thrombotic occlusion. FIG. 9 illustrates the method of use via either a percutaneous or transfemoral access site. In this scenario, the access sheath 220 is positioned as described above and can be advanced into the internal carotid artery until the sheath tip is as distal as safe. The spine aspiration catheter 320 is then preloaded onto the microcatheter 400 and guidewire, and the coaxial assembly can be introduced into the carotid artery through the access sheath 220 and advanced into the cerebral vasculature. The microcatheter 400 and guidewire can be advanced across the occlusion. The tip of the spine aspiration catheter 320 can be advanced as distal as possible and close to the clot.

[0113] At this point, the guidewire can be removed and the retrievable stent device can be inserted through the microcatheter 400 until it is positioned across the occlusion. The microcatheter 400 can be retracted to place the stent. Suction can be initiated from the suction source at any point during device movement at a level appropriate for distal embolic protection, for example, when the guidewire or microcatheter 400 is crossing the occlusion, or prior to stent deployment. By initiating suction prior to stent deployment, emboli dislodged while crossing the lesion are not carried downstream in the artery recovery flow, but rather are captured within the catheter tip. Suction can be maintained while the retrievable stent device 500 is deployed. Typically, the stent is deployed for several minutes before being retracted to maximize engagement of the stent struts against the occlusion. The retrievable stent device 500 can then be retracted into the spine catheter 320 and continued to be retracted until it is completely removed from the proximal valve of the access sheath 220.

[0114] Alternatively, the stent device 500 can be retracted into the distal portion of the spine catheter 320, and the stent device 500 and spine catheter 320 can be retracted together from the access sheath 220. During the retraction step of the stent and / or catheter, suction can be increased to a higher level to optimize clot aspiration and minimize distal embolization. The access sheath 220 has a proximal extension 240 with a valve on the connector, the device 500 can be retracted into the proximal extension 240, the valve closed, then the proximal hemostatic valve 234 can be opened wide, and the stent device 500 or stent device / spine catheter combination can be withdrawn. The proximal extension 240 can then be flushed via the valve flush line 236 and aspiration line 230 before the same or an alternative device is reinserted for another thrombectomy attempt, if the procedure indicates.

[0115] Alternately, after placing the aspiration catheter 320, the elongated or segmented stent retriever 500 is placed as described above with the microcatheter 400 and then expanded such that a portion of the expandable portion 510 is across the thrombus and a portion is in the distal segment 322 of the catheter 320. After the expandable portion 510 is expanded, suction can be initiated such that the thrombus is completely aspirated from the blood vessel and catheter 320 into the suction source 600 or into the distal tip and / or distal lumen 323 of the catheter 320. At that point, the elongated or segmented stent retriever 500 can be carefully pulled into the catheter 320 while suction is being applied. At this point, any clots lodged in the catheter 320 and / or debris dislodged during this step should be aspirated into the catheter 320. The stent retriever device 500 should be completely removed from the working channel 323 of the catheter 320 to completely clear the occluding material from the lumen 323.

[0116] In any of these scenarios, the suction source may be a variable or multi-state suction source configured to maximize suction force against the thrombotic occlusion while minimizing blood loss during free flow within the catheter.

[0117] In another exemplary method, the access sheath 220 has an occlusion balloon 246. As shown in Figure 7, the balloon 246 can be inflated during steps of the procedure where there is a high risk of distal embolism, such as during retraction of a clot-attached stent device 500 or spined catheter 320. The balloon 246 has the effect of stopping antegrade flow and increasing suction in the carotid artery, thereby increasing clot aspiration and reducing the risk of distal embolism.

[0118] In another exemplary method, the access sheath 220 has an expandable distal tip. In this manner, the distal tip can be expanded some time after the access sheath tip reaches the desired site, but before the spine catheter 320 is retracted into the access sheath 220. This method can reduce the chance of distal embolism resulting from dislodging clots attached to the distal tip of the spine catheter 320, since the distal tip is retracted into the tip of the sheath 220. Instead, the expanded or inflated tip of the access sheath acts as a funnel to capture any clots.

[0119] In another exemplary method, as briefly described above, the access sheath 1220 has a side opening 1219 (best shown in FIG. 12C). In this method, a spined catheter 1320 having a spined dilator 1340 extending through a lumen 1323 of a distal lumen 1322 of the catheter 1320 can be advanced through the lumen 1223 of the access sheath 1220 toward the distal end region of the sheath body n1222. The distal tip of the distal lumen 1322 of the spined catheter 1320 (which may have a spined dilator extending through the distal lumen 1322 forming the most distal end of the catheter system) can exit the lumen 1223 via the side opening 1219 and then further advanced distally beyond the distal tip of the access sheath 1220. The incorporation of angled feature 1217 or other internal features into the distal end region of lumen 1223 can form a surface against which the tip of the dilator can be deflected to direct the catheter 1320 away from the longitudinal axis A of the lumen 1223 of the sheath body 1222 and toward the side opening 1219 to achieve a smooth transition or exit from the lumen 1223. The distal tip 1346 of the dilator 1340 can abut against the angled feature 1217 and be angled toward the side opening 1219 at a slight angle away from the longitudinal axis of the sheath body 1222. As described elsewhere herein, the sheath body 1222, and thus the side openings 1219, can be rotatable about the longitudinal axis A such that one or more side openings 1219 can be positioned to allow the catheter 1320 to extend distally therethrough in a desired orientation relative to the longitudinal axis A of the sheath 1220. This is often dictated by the anatomy encountered by the operator. Also, as described elsewhere herein, an overlap region 1120 is formed between the distal lumen 1322 of the catheter and the access sheath body 1222. A seal element 1336 can be positioned on an exterior surface of the distal lumen 1322, for example, near a proximal end region of the distal lumen 1322, and can be disposed within the overlap region 1120.The seal formed allows complete transmission of suction forces through the continuous lumen formed by the lumen 1323 of the lumen 1322 and the lumen 1223 of the access sheath body 1222 when the dilator 1340 is withdrawn from the lumen 1323 of the lumen 1322 .

[0120] In another exemplary method, the suction source 600 is connected to a blood collection bath that maintains the integrity of the blood so that it can be safely returned to the patient at the end of the thrombectomy portion of the procedure, either directly or with post-treatment of the blood such as cell washing and / or hemofiltration. In another exemplary method, the suction source is connected to a blood shunt that is in turn connected to a device such as a venous sheath or venous return catheter that allows blood to be returned to the patient during the procedure without the need for a blood bath. In another exemplary method, the blood is collected in the bath and discarded at the end of the procedure.

[0121] In another exemplary method, an access sheath 1220 is delivered from a femoral insertion site into the subclavian or external carotid artery, as described elsewhere herein. The access sheath 1220 can be delivered to the carina of a bifurcation between a target vessel, such as the internal carotid artery (ICA) containing an embolus, and another vessel, such as the external carotid artery (ECA). Once the access sheath 1220 is positioned, a working device, such as a splined aspiration catheter 1320, can be delivered through the lumen 1223 of the access sheath 1220 into the target vessel. As described elsewhere herein, the lumen 1223 of the access sheath 1220 and the lumen 1323 of the catheter 1320 are adjacent, forming an increased diameter for aspiration. An 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 may extend distally from the lumen 1223 of the access sheath 1220 through an opening 1221 at the distal tip of the access sheath 1220 or through a side opening 1119 near the distal region of the access sheath 1220. The body 1222 of the access sheath 1220 may be oriented to provide optimal placement of the side opening 1119 relative to the anatomy. The overlap region 1120 between the distal lumen 1322 of the catheter 1320 and the access sheath body 1222 may form a seal and fully transmit suction forces through the adjacent lumen formed between the lumen 1323 of the lumen 1322 and the lumen 1223 of the access sheath body 1222, as well as provide a seal against delivery of fluids to the target vessel, such as angiographic contrast injection, saline, one or more drugs or other materials, directly into the neurovascular anatomy. By having the working lumen 1223 of the access sheath 1220 provide the majority of the suction column, the spined aspiration catheter 1320 can generate a stronger suction force. As described elsewhere herein, the dimensions of the lumen 1323 of the distal lumen 1322 of the aspiration catheter 1320 can be smaller than the diameter of the lumen 1223 of the access sheath 1220, reduced by the diameter of the spine 1330 extending therethrough.The increased diameter of the lumen can, for example, create a larger aspiration column than that of a larger caliber catheter having a similar overall length. The spined aspiration catheter 1320 can also be used as a support delivery catheter, for example, when an operator desires to reach difficult to reach landmarks in the carotid petrous or cerebral vasculature. More specifically, after delivery of the spined aspiration catheter 1320 through the working lumen 1223 of the access sheath 1220 into the target vessel, a second working device, such as a guidewire, microcatheter, stent retriever, etc., can be delivered through the lumen 1323 to a more distal anatomical structure to perform another procedural operation, as described elsewhere herein.

[0122] Although the specification contains many specific examples, these should not be construed as limitations on the scope of the claimed or claimable invention, but as describing features specific to particular embodiments. Certain features described in the specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the specification in the context of a single embodiment may also be implemented separately in multiple embodiments or in suitable subcombinations. Furthermore, even if features are described above as functioning in a particular combination, and even if originally claimed as such, one or more features from the claimed combination may in some cases be excluded from that combination, and the claimed combination may also involve subcombinations or variations of the subcombination. Similarly, although operations are shown in the figures in a particular order, such operations should not be understood as requiring that the operations be performed in the particular order or sequence shown, or that all of the operations shown be performed, to achieve desirable results. Thus, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

1. An intravascular access system for facilitating intraluminal neurovascular medical procedures via an access sheath, comprising: a flexible distal lumen having an inner diameter defining a lumen extending between a proximal opening at a proximal end of the lumen and a distal opening at a distal end of the lumen; a rigid spine coupled to at least the proximal end of the lumen and extending proximally therefrom; and the intravascular access system comprising: a dilator having a flexible distal dilator portion sized to be received within the lumen of the lumen and a rigid dilator spine extending proximally from the distal dilator portion.

2. The system of claim 1 , wherein, in use, the dilator spine is aligned side-by-side with a spine of a catheter.

3. The system of claim 1 or 2, wherein the distal dilator portion has a tapered distal tip.

4. The system according to any one of claims 1 to 3, wherein the expander has at least a length that enables a distal tip of the expander to protrude from the distal opening of the lumen.

5. The system of any of claims 1 to 4, wherein the dilator is generally tubular along at least a portion of its length.

6. The system of any of claims 1 to 5, wherein the proximal end of the catheter spine includes a gripping mechanism configured to be gripped by a user to move the catheter through the access sheath.

7. 7. The system of claim 6, wherein the proximal end of the dilator spine has a tab configured to engage with the gripping feature on the catheter spine.

8. The system of claim 7 , wherein the catheter and the dilator are in a locked configuration such that they can be advanced as a single unit through the access sheath.

9. 9. The system of claim 7 or 8, wherein the gripping mechanism and the dilator tab are removably coupled such that in a locked configuration, the dilator tab engages the gripping mechanism and in an unlocked configuration, the dilator disengages from the gripping mechanism.

10. The system of any one of claims 7 to 9, wherein the dilator tabs are fixed to the dilator.

11. The system of any of claims 7 to 9, wherein the dilator tab is slidable on the dilator to accommodate different relative positions between the dilator and the catheter.

12. The system of any of claims 1 to 11, wherein the distal dilator portion can include one or more detents on an outer surface configured to engage correspondingly shaped surface features on an inner surface of the lumen through which the dilator portion extends.

13. The system of any one of claims 1 to 12, wherein the dilator spine and the catheter spine have similar stiffness and kink resistance.

14. The system of any of claims 1 to 13, wherein the dilator has a visual marker at the distal and / or proximal end of the distal tip.

15. The system of any of claims 1 to 14, wherein a distal end region of the dilator is more flexible and becomes stiffer towards a proximal end region of the dilator.

16. The system of any one of claims 1 to 15, wherein the catheter spine and the dilator spine are configured to allow the luminal portion to be slidably moved in both directions through the lumen of the access sheath and to allow the luminal portion to be moved into the cerebral vasculature to reach the treatment site.

17. An intravascular access system for facilitating intraluminal neurovascular medical procedures via an access sheath, comprising: an access sheath including a sheath body having an inner diameter defining a lumen between a proximal end and a distal end of the sheath body and at least one opening from the lumen proximate a distal end region of the sheath body; a suction or support catheter including a flexible distal lumen having an outer diameter sized for insertion through the lumen of the access sheath, an inner diameter defining a lumen extending between a proximal opening at a proximal end of the lumen and a distal opening at a distal end of the lumen, and a length between the distal opening and the proximal opening; and a rigid spine at least coupled to the proximal end of the lumen and extending proximally therefrom; the rigid spine is configured to allow bidirectional sliding movement of the lumen through the lumen of the access sheath and out of at least one opening to move the lumen into a cerebral vasculature to reach a treatment site; and The intravascular access system, wherein when the distal end of the lumen is extended into a cerebral blood vessel to reach a treatment site, an outer diameter portion of the lumen seals against the inner diameter of the access sheath.

18. 20. The system of claim 17, wherein the lumen and the sheath body are concentrically disposed, and the lumen of the lumen and the lumen of the sheath body form a continuous aspiration lumen from the distal end of the lumen to the proximal end of the sheath body.

19. The system of claim 18 , wherein the continuous aspiration lumen is operable to aspirate fluids and debris from the distal opening of the lumen.

20. 20. The system of claim 18 or 19, wherein the continuous aspiration lumen is operable to deliver a substance through the distal opening of the lumen.

21. The system of any of claims 17-20, wherein the continuous aspiration lumen forms an increasing diameter section where the lumen of the lumen portion tapers into the lumen of the sheath body.

22. The system according to any one of claims 17 to 21, wherein the lumen of the lumen portion is shorter than the lumen of the sheath body.

23. The system of any of claims 17-22, wherein the lumen and the sheath body form an overlap region when the lumen extends distally beyond at least one opening in the sheath body.

24. 24. The system of claim 23, wherein an outer diameter of the lumen approaches an inner diameter of the lumen of the sheath body such that a seal is formed by the overlap region.

25. 25. The system of claim 24, wherein the seal is configured to be capable of sealing against a vacuum of up to 25 inches of mercury (inHg) or up to 28 inches of mercury (inHg).

26. 25. The system of claim 24, wherein the seal in the overlap region is configured to be capable of sealing against a pressure of up to 300 mmHg.

27. The system of any one of claims 24 to 26, wherein the seal is located distal to a proximal end of the lumen and proximal to at least one opening in the sheath body.

28. The system of any of claims 24-27, further comprising a sealing element located on an exterior surface of the lumen.

29. 30. The system of claim 28, wherein the sealing element includes an increased diameter or protruding feature in the overlap region.

30. The system of claim 28 , wherein the sealing element includes one or more external ridge features.

31. The system of claim 30 , wherein the one or more external ridge features are compressible when the lumen is inserted into the lumen of the sheath body.

32. 30. The system of claim 28, wherein the sealing element has one or more angled surfaces that bias against an inner surface of the sheath body lumen.

33. 30. The system of claim 28, wherein the sealing element includes one or more expansion members that act to seal.

34. The system according to any one of claims 17 to 33, wherein the sheath body has an outer diameter suitable for insertion into a carotid artery.

35. 35. The system of claim 34, wherein the outer diameter of the sheath body is between 5 Fr and 7 Fr.

36. The system of any one of claims 17 to 35, wherein the sheath body has a length between the proximal end and the distal end suitable for positioning the distal end of the sheath body in the petrous portion of the internal carotid artery via a transfemoral approach.

37. 37. The system of claim 36, wherein the length of the sheath body is between 80 cm and 105 cm.

38. The system of any one of claims 17 to 37, wherein the length of the lumen is between 10 cm and 25 cm.

39. 39. The system of any of claims 17-38, wherein a length of the lumen is shorter than a length of the sheath body such that a seal remains between the overlap region of the lumen and the inner diameter of the sheath body when the catheter is retracted into the sheath body.

40. The system of any one of claims 17 to 39, wherein the spine is longer than the overall length of the sheath body.

41. The system of any of claims 17-40, wherein the lumen comprises three or more layers including an inner lubricious liner, a reinforcing layer, and an outer jacket layer.

42. 42. The system of claim 41, wherein the outer jacket layer is constructed from discrete portions of polymer having different durometers, compositions, and / or thicknesses to vary flexibility along the length of the distal lumen.

43. The system of any of claims 17 to 42, wherein the distal lumen is sized to be traversed into a cerebral artery.

44. The system of any one of claims 17 to 43, wherein the inner diameter of the distal lumen is between 0.040 inches and 0.088 inches.

45. The system of claims 17-44, wherein the outer diameter of the lumen approaches the inner diameter of the sheath body to form a seal area in the overlap area while allowing movement of the catheter through the sheath body.

46. 46. ​​The system of any of claims 17-45, wherein the catheter has a tapered shape toward the distal opening such that a distal-most end of the lumen has a smaller outer diameter than a more proximal region of the lumen near where the lumen seals with the sheath body.

47. The system of any of claims 17 to 46, wherein the distal end region of the sheath body includes an occlusion element.

48. The system of any of claims 17 to 47, wherein the distal end region of the sheath body includes an enlarged distal tip.

49. The system of any of claims 17 to 48, wherein at least one opening from the lumen comprises a lateral opening located away from the distal tip of the sheath body.

50. 50. The system of claim 17, wherein a distal tip of the sheath body includes an angled feature configured to angle the catheter away from a longitudinal axis of the sheath body lumen and out through the at least one opening.

51. The system of any one of claims 17 to 50, wherein the spine is longer than the overall length of the sheath body.

52. The system of any of claims 17 to 51, wherein the spine has an outer dimension of between 0.014 inches and 0.018 inches.

53. The system of claims 17-52, wherein the spine is a hypotube having a guidewire passage extending therethrough.

54. The system of any of claims 17 to 53, wherein the spine is a ribbon having an outer dimension of a thickness between 0.010 inches and 0.025 inches.

55. 55. The system of claim 54, wherein the ribbon is curved along at least a portion of a circular arc.

56. The system of any of claims 17 to 55, wherein the spine is configured to rotate the lumen about a longitudinal axis of the access sheath.

57. The system of any one of claims 17 to 56, wherein the spine is eccentrically coupled to the lumen, and the spine extends proximally from the lumen toward outside the proximal end of the sheath body.

58. The system of any of claims 17 to 57, wherein the proximal end of the lumen has an angled cut.

59. 60. The system of claim 58, wherein the angled cut is generally flat or curved.

60. The system of any of claims 17 to 59, wherein the sheath body has one or more visual markers at the distal end region of the sheath body.

61. 61. The system of any of claims 17 to 60, wherein the distal lumen has one or more visual markers at a distal end region of the lumen, a proximal end region of the lumen, or both.

62. 62. The system of claim 60 or 61, wherein the one or more visual markers on the sheath body and the one or more visual markers on the lumen are visually distinguishable.

63. The system of any of claims 60 to 62, wherein the spine has one or more visual markers.

64. 64. The system of claim 63, wherein the one or more visual markers on the spine indicate an overlap between the distal lumen and the sheath body.

65. 65. The system of claim 63 or 64, wherein the one or more visual markers on the spine are positioned such that when the visual marker on the spine is aligned with a portion of the access sheath, the catheter is positioned in a distal-most position having a minimum overlap length required to form a seal between the catheter and the sheath body.

66. The system of any of claims 17 to 65, further comprising a dilator, the dilator including a flexible distal dilator portion having a distal tip and dimensioned for receipt within the lumen of the catheter.

67. 67. The system of claim 66, wherein the expander is a tubular element along at least a portion of its length.

68. 67. The system of claim 66, wherein the expander is a solid rod formed of a malleable material configured to be shaped by a user.

69. 67. The system of claim 66, wherein the expander is a rigid expander spine extending proximally from the expansion portion.

70. 70. The system of claim 69, wherein the dilator spines are coaxial.

71. 71. The system of claim 70, wherein the coaxial dilator spine has a lumen extending therethrough.

72. 70. The system of claim 69, wherein the dilator spine is eccentric.

73. A system according to claims 69 to 72, wherein in use, the dilator spine is aligned alongside the spine of the catheter.

74. The system of any one of claims 66 to 73, wherein the distal tip is tapered.

75. 75. The system of claim 74, wherein the dilator has at least the same length as the catheter such that the distal tip protrudes from the distal opening of the lumen.

76. The system of any of claims 69-75, wherein the proximal end of the spine includes a gripping mechanism configured to be gripped by a user to move the catheter through the access sheath.

77. 77. The system of claim 76, wherein the proximal end of the dilator spine has a tab on the catheter spine configured to engage with the gripping feature.

78. 78. The system of claim 77, wherein the catheter and the dilator are in a locked configuration such that they can be advanced as a single unit through the sheath body.

79. 79. The system of claim 77 or 78, wherein the gripping mechanism and the dilator tab are removably coupled such that in a locked configuration, the dilator tab engages the gripping mechanism and in an unlocked configuration, the dilator disengages from the gripping mechanism.

80. The system of any one of claims 77 to 79, wherein the dilator tab is fixed to the dilator.

81. The system of any of claims 77 to 79, wherein the dilator tab is slidable on the dilator to accommodate different relative positions between the dilator and the catheter.

82. The system of any of claims 66-81, wherein the distal dilator portion can include one or more detents on an outer surface configured to engage correspondingly shaped surface features on an inner surface of the lumen through which the dilator portion extends.

83. The system of any one of claims 69 to 82, wherein the dilator spine and the catheter spine have similar stiffness and kink resistance.

84. The system of any of claims 66 to 83, wherein the expander has a visual marker at the distal and / or proximal end of the distal tip.

85. The system of any of claims 66 to 84, wherein a distal end region of the expander is more flexible and becomes stiffer towards the proximal end region of the expander.

86. The system of any one of claims 17 to 85, wherein the access sheath further comprises a connector connecting the proximal end of the sheath body to a proximal hemostasis valve.

87. 87. The system of claim 86, wherein the proximal hemostasis valve has an adjustable opening sized large enough to allow the catheter to be removed without dislodging clots thereon.

88. 88. The system of claim 86 or 87, wherein, when used with the access sheath, the rigid spine of the catheter extends proximally from the lumen through the lumen of the access sheath and out of the proximal hemostasis valve of the access sheath.

89. The system of any of claims 86-88, wherein the connector provides a connection to an aspiration line at the proximal end of the sheath body.

90. A system according to any one of claims 86 to 89, wherein the connector has a large diameter lumen and connects to a large diameter suction line.

91. 91. The system of claim 89 or 90, wherein the suction line connects to a suction source.

92. 92. The system of claim 91, wherein the suction source is an active suction source.

93. A system according to any one of claims 89 to 92, wherein the suction line connects to a forward drip or irrigation line.

94. The system of any one of claims 17 to 93, wherein the access sheath further comprises a proximal extension, and wherein the distal lumen of the catheter remains within the proximal extension when withdrawn from the lumen of the sheath body.

95. The system of any of claims 17 to 94, wherein an inner diameter of the lumen is sized to allow placement of an interventional device therethrough.

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