Methods and systems for treatment of acute ischemic stroke

Abstract

To provide methods and systems for transcervical access to the cerebral arterial vessels, and methods and systems for treatment of cerebral occlusion, including ischemic stroke.SOLUTION: The methods and devices may include methods and devices which may provide aspiration and passive flow reversal and protect the cerebral penumbra during the procedure to minimize injury to brain, as well as distal catheters and devices to remove occlusion. The methods and devices that provide passive flow reversal may also offer the user a degree of flow control. Devices and methods are disclosed which provide a way to securely close the access site in the carotid artery to avoid potentially devastating consequences of a transcervical hematoma.SELECTED DRAWING: Figure 32

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to the following co-pending U.S. provisional patent applications: (1) U.S. Provisional Patent Application No. 61 / 515,736, filed August 5, 2011, (2) U.S. Provisional Patent Application No. 61 / 543,019, filed October 4, 2011, (3) U.S. Provisional Patent Application No. 61 / 547,597, filed October 14, 2011, and (4) U.S. Provisional Patent Application No. 61 / 579,581, filed December 22, 2011. The disclosures of the U.S. provisional patent applications are incorporated herein by reference in their entireties. [Background technology]

[0002] The present disclosure relates generally to medical methods and devices for treating acute ischemic stroke. In particular, the present disclosure relates to methods and systems for transcervical access to cerebral arterial vasculature and for treating cerebral occlusion.

[0003] Acute ischemic stroke is the sudden interruption of adequate blood flow to part of the brain, usually caused by a clot or other embolus that has become lodged or formed in one of the blood vessels supplying the brain. If this blockage is not quickly relieved, ischemia will result in permanent neurological damage or death. The time frame for effective treatment of stroke is within three hours with intravenous (IV) thrombolytic therapy and within six hours with site-directed intra-arterial thrombolytic therapy or interventional recanalization of the occluded cerebral artery. Reperfusing the ischemic brain after this time frame offers no overall benefit to the patient and may actually cause harm due to the increased risk of intracranial hemorrhage associated with the use of fibrinolytic agents. Even within this time frame, there is strong evidence that the shorter the time from symptom onset to treatment, the better the outcome. Unfortunately, it is rare to recognize symptoms, transport the patient to stroke treatment, and ultimately treat these patients within this time frame. Despite advances in treatment, stroke remains the third leading cause of death in the United States.

[0004] Endovascular treatment of acute stroke consists of either the intra-arterial administration of thrombolytic drugs (e.g., recombinant tissue plasminogen activator (rtPA)) or mechanical removal of the blockage, often a combination of the two. As mentioned above, these interventional procedures must occur within hours of symptom onset. Both intra-arterial (IA) thrombolysis and interventional thrombectomy involve accessing the blocked cerebral artery. Intra-arterial (IA) thrombolysis, like intravenous (IV) thrombolysis, has the limitation that infusion may take several hours to effectively dissolve the clot.

[0005] Mechanical treatments include capturing and removing the clot, dissolving the clot, fragmenting and aspirating the clot, and / or creating a channel through the clot. One of the first mechanical devices developed for stroke treatment is the MERCI Retriever System (Concentric Medical, Redwood City, California). A balloon-tipped guide catheter is used to access the internal carotid artery (ICA) from the femoral artery. A microcatheter is placed through the guide catheter and used to deliver a coil-tipped retriever across the clot, which is then withdrawn to deploy the retriever around the clot. The balloon is then inflated, and with a syringe connected to the balloon guide catheter to aspirate the guide catheter during clot retrieval, the microcatheter and retriever are withdrawn into the balloon guide catheter to pull the clot. The device provides initially favorable results compared with thrombolytic therapy alone.

[0006] Other thrombectomy devices utilize expandable cages, baskets, or snares to capture and retrieve clots. A range of devices using active laser or ultrasound energy to fragment clots have also been utilized. Other active energy devices have been used in conjunction with intra-arterial administration (intra-arterial infusion) of thrombolytic agents to promote clot dissolution. Many of these devices have been used in conjunction with suction to aid in clot removal and reduce the risk of embolism. Frank suction of clots has also been utilized with single-lumen catheters and syringes or suction pumps, with or without adjunct disruption of the clot. To enhance the efficiency of thrombectomy procedures, devices that apply powered fluid vortices in conjunction with suction have been utilized. Finally, when removal or dissolution of the clot is not possible, balloons, stents, and temporary stents have been used to create a lumen (blood vessel) through the clot. Temporary stents, sometimes called stentrievers or revascularization devices, can be used not only to restore blood flow to the vessel, but also to remove or retrieve the clot. Summary of the Invention [Problem to be solved by the invention]

[0007] <Typical problems with current technology> Interventions in the cerebrovascular system often present unique access challenges. Most neurointerventional procedures use transfemoral access from the femoral region to the carotid or vertebral artery and from there to the target cerebral artery. However, this access route is often tortuous and may contain stenotic plaque material in the aortic arch and at the origin of the carotid and brachiocephalic vessels, presenting a risk of embolic complications during the access portion of the procedure. Furthermore, cerebral vessels are typically much more delicate and prone to perforation than the coronary or other peripheral vasculature. In recent years, interventional devices (e.g., wires, guide catheters, stents, and balloon catheters) have become significantly smaller and more flexible to better function within the neurovascular anatomy. However, device access challenges make many neurointerventional procedures relatively difficult or impossible. In the case of acute ischemic stroke, where "time is brain," these additional difficulties will have a significant clinical impact.

[0008] Another challenge in cerebrovascular interventions is the risk of cerebral embolism. During efforts to remove or dissolve clot obstructions in cerebral arteries, there is a significant risk of clot fragmentation, which can generate embolic particles that can travel downstream and compromise cerebral perfusion, potentially leading to neurologic events. During carotid artery stenting (CAS) procedures, embolic protection devices and systems are commonly used to reduce the risk of embolic material entering the cerebral vasculature. Device types include intravascular filters, reverse flow systems, or static flow systems. Unfortunately, these embolic protection systems are not used in the interventional treatment of acute ischemic stroke due to the delicate anatomy and access challenges, as well as the need for rapid intervention. Some current mechanical clot retrieval procedures use aspiration as a means to reduce the risk of embolism and facilitate clot removal. For example, the MERCI retriever system recommends attaching a large syringe to the guide catheter and aspirating the proximal artery while pulling the clot back into the guide. However, this process requires a second operator, potentially necessitating interruptions in aspiration if the syringe needs to be emptied and reattached, and does not allow for control of the speed and timing of aspiration. This control would be important if the patient's tolerance for backflow is questionable. Furthermore, there is no protection against embolic debris during the initial crossing of the clot with the microcatheter and deployment of the retriever device. While other components are utilized to mechanically fragment the clot, aspiration systems such as the Penumbra System utilize a catheter that aspirates against the clot. This system is limited by the level of aspiration possible with current catheter designs and, at times, by the ability to navigate a large catheter to the location of the clot.

[0009] A significant drawback of current acute stroke interventions is the time required to restore blood perfusion to the brain, which can be divided into the time required to access the blocked cerebral artery and the time required to restore blood flow through the blockage. Restoring blood flow by thrombolytic therapy, mechanical thrombectomy, or other means often takes several hours, during which time brain tissue is deprived of sufficient oxygen. During this time, there is a risk of permanent brain tissue damage. Means of shortening the procedure time and / or providing oxygen to brain tissue during the procedure would reduce this risk. [Means for solving the problem]

[0010] <Summary> Disclosed are methods and devices that allow safe, rapid, relatively short, and straight transcervical access to cerebral arteries for treating acute ischemic stroke. The methods and devices include a distal catheter and device for removing the occlusion. The methods and devices are also included to provide aspiration and passive flow reversal to facilitate occlusion removal as well as minimize distal embolism. The system provides the user with a degree of blood flow control to address the specific hemodynamic demands of the cerebral vasculature. The disclosed methods and devices also include methods and devices for protecting the cerebral penumbra during the procedure to minimize brain damage. Furthermore, the disclosed methods and devices provide a means of securely occluding the access site to the cerebral arteries to avoid the potentially devastating consequences of a transcervical hematoma.

[0011] In one aspect, a system of devices for treating a cerebral artery blockage in a patient is provided, comprising: a transcervical access sheath adapted for direct introduction into the common carotid artery through an opening in the artery, the opening being located above the patient's clavicle and below a bifurcation where the common carotid artery bifurcates into the internal carotid artery and the external carotid artery, the transcervical access sheath having an internal lumen; a distal catheter sized and shaped for axial insertion through the lumen of the transcervical access sheath such that the distal catheter can be inserted through the transcervical access sheath into a cerebral artery, the distal catheter having a lumen defined by an inner diameter; an elongate inner member sized and shaped for axial insertion through the lumen of the transcervical access sheath, the inner member having an inner lumen; a guidewire configured to be insertable into the cerebral artery through the lumen of the inner member, The system is disclosed in which the inner member has an outer diameter configured to provide a smooth transition between the inner diameter of the distal catheter and the outer diameter of the guidewire.

[0012] In another aspect, there is provided a system of devices for treating an occlusion in a cerebral artery in a patient, comprising: a transcervical access sheath adapted for direct introduction into the common carotid artery through an opening in the artery, the opening being located above the patient's clavicle and below a bifurcation where the common carotid artery bifurcates into the internal carotid artery and the external carotid artery, the transcervical access sheath having an internal lumen; The system discloses a distal catheter sized and shaped for axial insertion through the lumen of the transcervical access sheath so that the distal catheter can be inserted into a cerebral artery through the transcervical access sheath, the distal catheter having a first lumen and a smaller second lumen, the distal-most portion of the second lumen being positioned inside an extension that protrudes distally beyond a distal opening formed by the first lumen.

[0013] In another aspect, there is provided a system of devices for treating an occlusion in a cerebral artery in a patient, comprising: a transcervical introducer sheath adapted for direct introduction into a common carotid artery through an opening in the artery, the opening being located above the patient's clavicle and below a bifurcation point where the common carotid artery bifurcates into an internal carotid artery and an external carotid artery, the transcervical introducer sheath having an internal lumen; a blood flow line connected to the introducer sheath, the blood flow line providing a path for blood to flow from the introducer sheath to a return site; a hemostatic valve in a proximal region of the introducer sheath that provides access to the lumen of the introducer sheath while preventing blood loss; and a guide catheter sized and shaped for insertion through the hemostatic valve and into the lumen of the introducer sheath so as to provide access to a cerebral artery through the interior of the guide catheter.

[0014] In another aspect, there is provided a method of treating a cerebral artery occlusion, comprising: making an incision in the common carotid artery; inserting a transcervical access sheath through the incision into the common carotid artery and deploying a distal end of the sheath into the common carotid artery or the internal carotid artery, the access sheath having an internal lumen; inserting a first distal catheter into the lumen of the access sheath; positioning a distal end of the first distal catheter in the cerebral artery adjacent the occlusion; applying suction through the first distal catheter to capture the occlusion at the distal end of the first distal catheter; and retracting the distal end of the first distal catheter into the access sheath to retract the occlusion into the access sheath.

[0015] Other features and advantages will become apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the invention. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 shows an exemplary embodiment of a system of devices for transcervical access and acute ischemic stroke treatment, illustrating a balloon-tipped arterial access device inserted directly into the carotid artery, a distal catheter, and a thrombectomy device. [Figure 2] FIG. 2 shows an alternative embodiment in which the arterial access device is inserted into the carotid artery through a separate introducer sheath. [Figure 3] FIG. 3 shows an embodiment in which the introducer sheath has an occlusion balloon and a connection to a blood flow line. [Figure 4] FIG. 4 shows an alternative embodiment of an arterial access device having two occlusion balloons and an opening between the two balloons. [Figure 5] FIG. 5 shows an alternative embodiment of an arterial access device that includes two telescoping sections. [Figure 6] FIG. 6 shows an embodiment of a balloon-tipped anchoring device. [Figure 7] FIG. 7 shows an embodiment of a mechanically expandable tipped anchor guidewire. [Figure 8] FIG. 8 shows an embodiment of a distal catheter with a tapered coaxial inner member. [Figure 9] FIG. 9 shows another embodiment of a distal catheter with a tapered coaxial inner member. [Figure 10] FIG. 10 shows an embodiment of a combined arterial access device and distal catheter. [Figure 11] FIG. 11 shows an embodiment of a distal catheter having a second lumen for maintaining guidewire access. [Figure 12]FIG. 12 shows an embodiment of a distal catheter having a second lumen for maintaining guidewire access. [Figure 13] FIG. 13 illustrates an embodiment of a telescoping configured distal catheter and arterial access device. [Figure 14] FIG. 14 shows an alternative embodiment of the system with the addition of an occlusion device. [Figure 15] FIG. 15 shows an embodiment of the system with the addition of a suction source attached to the arterial access device, a filter, and a one-way check valve. [Figure 16] FIG. 16 shows an embodiment of the system with the addition of a suction source, filter, and one-way check valve attached to both the arterial access device and the distal catheter. [Figure 17] FIG. 17 shows an embodiment of the system with a single suction source, filter, and one-way check valve attached to both the arterial access device and the distal catheter, and additional valves for connecting the two devices to the suction source. [Figure 18] FIG. 18 shows an embodiment of the system with the addition of flow controllers attached to both the arterial access device and the distal catheter. [Figure 19] FIG. 19 shows an embodiment of a suction source. [Figure 20] FIG. 20 shows an alternative embodiment of the suction source. [Figure 21] FIG. 21 shows an embodiment of the system that adds a flow reverse circuit that includes a venous return site. [Figure 22] FIG. 22 shows an embodiment of a thrombectomy device. [Figure 23] FIG. 23 shows an embodiment of a thrombectomy device. [Figure 24] FIG. 24 shows an embodiment of a thrombectomy device. [Figure 25] FIG. 25 shows an embodiment of a thrombectomy device. [Figure 26]FIG. 26 shows an embodiment of a thrombectomy device. [Figure 27] FIG. 27 shows an embodiment of a thrombectomy device. [Figure 28] FIG. 28 shows an embodiment of a thrombectomy device. [Figure 29] FIG. 29 shows an embodiment of a thrombectomy device. [Figure 30] FIG. 30 shows an embodiment of a dual lumen microcatheter. [Figure 31] FIG. 31 shows an embodiment of a distal perfusion catheter. [Figure 32] FIG. 32 shows an alternative embodiment of the distal perfusion catheter. [Figure 33] FIG. 33 shows a different embodiment of a distal perfusion catheter with an occlusion balloon. [Figure 34] FIG. 34 shows a different embodiment of a distal perfusion catheter with an occlusion balloon. [Figure 35] FIG. 35 shows a different embodiment of a distal perfusion catheter with an occlusion balloon. [Figure 36] FIG. 36 shows a different embodiment of a distal perfusion catheter with an occlusion balloon. [Figure 37] FIG. 37 shows another embodiment of a distal perfusion catheter. [Figure 38] FIG. 38 shows an embodiment of the system with the addition of a distal balloon catheter configured to perfuse the proximal side of the balloon. [Figure 39A] FIG. 39A illustrates a method of using a distal balloon catheter configured to perfuse distal and / or proximal sides of the balloon. [Figure 39B] FIG. 39B illustrates a method of using a distal balloon catheter configured to perfuse distal and / or proximal sides of the balloon. [Figure 39C] FIG. 39C illustrates a method of using a distal balloon catheter configured to perfuse distal and / or proximal sides of the balloon. [Figure 39D]FIG. 39D illustrates a method of using a distal balloon catheter configured to perfuse distal and / or proximal sides of the balloon. DETAILED DESCRIPTION OF THE INVENTION

[0017] <Detailed explanation> Described herein are methods and devices that allow safe, rapid, relatively short, and straight transcervical access to the carotid artery and cerebral vasculature for the introduction of interventional devices for the treatment of ischemic stroke. Transcervical access provides a short, non-tortuous path from the vascular access point to the target treatment site, thereby reducing procedural time and difficulty compared to, for example, a transfemoral approach. Furthermore, this access route reduces the risk of embolic events due to navigation through diseased, angulated, or tortuous aortic arch or common carotid artery anatomy.

[0018] 1 shows a system of devices for accessing the common carotid artery (CCA) via a transcervical approach and for delivering devices to the cerebral vasculature. The system includes an arterial access device 2010 (sometimes referred to as an arterial access sheath), e.g., a sheath, having an internal lumen and a port 2015. The arterial access device 2010 is sized and shaped to be insertable into the common carotid artery via a transcervical incision or puncture and deployed in a location that provides access to the cerebral vasculature, e.g., the common carotid artery or the internal carotid artery. The port 2015 provides access to the internal lumen of the arterial access device and is configured to introduce additional devices into the cerebral vasculature via the arterial access device 2010.

[0019] In one embodiment, direct transcervical access to the common carotid artery with the arterial access device 2010 is achieved percutaneously via a skin incision or puncture. In an alternative embodiment, the arterial access device 2010 accesses the common carotid artery CCA via a direct surgical incision into the carotid artery. In another embodiment, the arterial access device provides access to the basilar artery BA or posterior cerebral artery PCA via a vertebral artery incision or percutaneous vertebral artery puncture to access an occlusion in the posterior cerebral vasculature, such as the posterior cerebral artery or basilar artery. The arterial access device may include an occlusion balloon to occlude antegrade blood flow. For entry into the common carotid artery, the arterial access device is inserted directly into an opening in the common carotid artery, the opening being located above the patient's clavicle and below the bifurcation of the patient's common carotid artery into the internal and external carotid arteries. For example, the opening may be located approximately 5 cm to 7 cm below the bifurcation of the patient's common carotid artery into the internal and external carotid arteries.

[0020] The system may also include one or more distal catheters 2030 to provide distal access to and local aspiration at locations distal to the distal-most end of the arterial access device 2010. A single distal catheter may be suitable for accessing and treating one or more occlusions. If more distal access is desired but not possible with the first distal catheter, a second, smaller diameter distal catheter may be inserted through or replace the first catheter. In some embodiments, the distal catheter 2030 is configured for insertion into the lumen of the arterial access device 2010 via the port 2015. The distal catheter 2030 may utilize a pre-placed guidewire, microcatheter, or other device that serves as a guide rail and support means to facilitate placement near the occlusion site. The distal catheter may also utilize a dilator element to facilitate placement over the guidewire through the vasculature. Once the distal catheter is positioned at or near the target site, the dilator may be removed. The distal catheter 2030 may then be used to apply suction to the occlusion, and the catheter 2030 or dilator may be used to deliver additional catheters and / or interventional devices to the occlusion site.

[0021] The methods and devices further include devices for passive aspiration as well as passive retrograde flow to facilitate occlusion removal and / or minimize distal embolization. The systems provide the user with a degree of flow control to address the specific hemodynamic requirements of the cerebral vasculature. The systems can include flow controllers, allowing the user to control the timing and mode of aspiration from one or more devices.

[0022] 1 , a thrombectomy device 4100 configured for transcervical access, such as a stentriever or coil retriever, may be deployed through an arterial access device to a thrombotic occlusion site. The thrombectomy device 4100 is inserted through the arterial access device 2010 and deployed across the occlusion in a cerebral vessel via a microcatheter. Optionally, a distal catheter 2030 may be used to facilitate navigation of the thrombectomy device to the occluded vascular site and / or to provide suction to the occlusion site while the thrombectomy device is retrieving the clot. The thrombectomy device and microcatheter are retracted in line into the distal catheter 2030 (if used) and into the arterial access device 2010 to retrieve the clot.

[0023] The disclosed methods and devices also include devices that protect the brain penumbra during the procedure to minimize brain damage. Distal perfusion devices may be used during the procedure to provide perfusion to the brain beyond the occlusion site, thereby reducing brain damage due to blood shortage. These perfusion devices also provide a means to reduce forward blood pressure on the occlusion in the blood vessel and to assist in removing the occlusion by suction, mechanical means, or both.

[0024] Furthermore, the disclosed methods and devices provide a means to reliably close the access site to the cerebral arteries to avoid the potentially serious consequences of a transcervical hematoma. The present disclosure provides additional methods and devices.

[0025] Arterial Access Devices According to Exemplary Embodiments The arterial access device 2010 shown in FIG. 1 is configured for direct insertion into the common carotid artery CCA without the use of a separate introducer sheath. In this configuration, the entry or distal tip of the device is tapered and includes a tapered dilator to allow the device to be smoothly introduced over a guidewire into the artery. The device 2010 may include an occlusion balloon 2020 configured to occlude the artery when inflated. In an alternative embodiment, the arterial access device 2010 does not include an occlusion balloon. The arterial access device further includes a proximal adapter. The proximal adapter includes a proximal port 2015 with a hemostatic valve to allow for introduction of the device while preventing or minimizing blood loss during the procedure. In one embodiment, the valve is a fixed-seal type passive valve. In alternative embodiments, the valve is an adjustable-opening valve, such as a Tuohy-Borst valve or a rotary hemostatic valve (RHV). The hemostatic valve may be integral with the proximal adapter or may be separately attached to the proximal end of the adapter via a Luer connection. The arterial access device 2010 may further include a connection to a blood flow line 2025 (or shunt), which may be connected to a passive or active backflow means. The blood flow line 2025 has a lumen that communicates with the lumen of the arterial access device 2010 to shunt blood from the arterial access device. In one embodiment, the blood flow line 2025 is a side arm or Y-arm 2027 attached to and extending from the arterial access device 2010 at a location between the distal and proximal ends of the arterial access device 2010. 1, the blood flow line 2025 is positioned distal to where the device enters the arterial access device's proximal port 2015. In an alternative embodiment, the blood flow line 2025 is attached to the Y-arm of a separately attached Twee-Borst valve.

[0026] The arterial access device 2010 may further include a balloon inflation lumen that fluidly connects the balloon to a second Y-arm of the proximal adapter. The Y-arm is attached to tubing 2028 that terminates in a one-way stopcock 2029. An inflation device, such as a syringe, may be attached to the stopcock 2029 to inflate the balloon when vascular occlusion is desired.

[0027] In one embodiment shown in FIG. 2 , the arterial access device is a guide catheter 2105 that is inserted into the CCA through a proximal hemostatic valve 2012 of a separate introducer sheath 2110. The arterial access device further includes a proximal adapter. The proximal adapter includes a proximal port 2015 with a hemostatic valve, allowing for introduction of the device while preventing or minimizing blood loss during the procedure. The guide catheter 2105 may include a lumen for balloon inflation. This lumen is attached to a Y-arm of the proximal adapter, which is connected to tubing 2128. The tubing 2128 terminates in a one-way stopcock 2129 for connection to a balloon inflation device. The guide catheter 2105 may include a second Y-arm 2107 in communication with the blood flow line 2125. Introduction through a separate sheath 2110 allows for removal of the guide catheter 2105 for flushing and reinsertion outside the patient's body or for exchange of the guide catheter 2105 for another guide catheter without removing the introducer sheath 2110, thereby maintaining arterial access through a transcervical incision. Additionally, this arrangement allows for repositioning of the occlusion balloon 2020 during the procedure without obstructing the arterial insertion site. Additionally, the embodiment of FIG. 2 allows for removal of the arterial access device 2105 and subsequent insertion of a vessel closure device through the introducer sheath 2110 at the end of the procedure.

[0028] In a variation of this embodiment, as shown in FIGURE 3, the introducer sheath 2110 includes an occlusion balloon 2205 and an inflation line and tubing 2318. Additionally, the introducer sheath 2110 may include a connection to a blood flow line 2310 for passive or active retrograde flow, which may be achieved as described in U.S. patent application Ser. Nos. 12 / 176,250 and 12,834,869, which are incorporated herein by reference. This embodiment may be useful when a patient has a carotid artery stenosis in addition to a cerebral artery occlusion, and the user wishes to treat the carotid artery stenosis under static or retrograde conditions as described in the cited patent applications, either before or after treatment of the cerebral artery occlusion.

[0029] In yet another embodiment, as shown in FIGURE 4, the arterial access device is a device 2105a with two occlusion balloons 2405, 2410 and a side opening 2415 disposed between the two balloons. The distal occlusion balloon 2410 is disposed at or near the distal end of the arterial access device 2105a, and the proximal occlusion balloon 2405 is disposed between the distal and proximal ends of the working portion of the arterial access device. The distal occlusion balloon 2410 is sized and shaped to be placed in the external carotid artery (ECA), and the proximal occlusion balloon 2405 is sized and shaped to be placed in the common carotid artery (CCA). Such a dual balloon configuration blocks blood flow from both the CCA and ECA to the internal carotid artery (ICA), which has a functionally similar effect to an occlusion balloon positioned in the ICA without inserting a device into the ICA. This may be advantageous when the ICA is diseased such that access could dislodge emboli and cause embolic complications, or when access to the ICA is severely tortuous and difficult to achieve, or both. A side opening 2415 in the working section of the arterial access device 2105 allows a device 2416 to be introduced through the arterial access device 2105a and inserted into the ICA through the side opening 2415 while blood flow is stopped or reversed to reduce or eliminate the risk of distal emboli. This device 2416 may then be advanced to the location of a cerebral artery occlusion to treat the occlusion.

[0030] In yet another embodiment, as shown in FIG. 5, the arterial access device is a multi-part (e.g., two-part) telescoping system 2105b. The first part is an introducer sheath 2110b configured for transcervical insertion into the CCA. The second part is a distal extension 2110c that is inserted through the proximal end of the introducer sheath 2110b to extend the reach of the sheath into the ICA. The distal end of the sheath 2110b and the proximal end of the extension 2110c form a lap junction 2113 such that a continuous lumen exists through the two devices when the extension is fully inserted. The lap junction may be of variable length such that the length of the combined telescoping system 2105b is somewhat variable. Distal extension 2110c includes a tether 2111 that allows for deployment and retrieval of distal extension 2110c through sheath 2110b. In one embodiment, the distal extension includes an occlusion balloon. In this embodiment, the tether includes a lumen for balloon inflation. The tether can be connected at its proximal end to a balloon inflation device. This arrangement provides the benefits of the two-part system shown in FIG. 2 without sacrificing luminal area.

[0031] In some embodiments, the working portion of the arterial access device, which enters the artery, is composed of two or more layers, including, for example, a first layer and a second layer. The inner liner is composed of a low-friction polymer, such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene), to provide a smooth surface for the device to advance through the lumen. The outer jacket material, which provides mechanical integrity to the liner, may be composed of materials such as Pebax, polyethylene, or nylon. The third layer may consist of a reinforcement between the liner and the jacket. The purpose of the reinforcement layer is to prevent flattening or kinking of the lumen as the device navigates through the bends of the vasculature and to provide a smooth means for device access as well as aspiration or reflux. The reinforcement may be formed from a metal such as stainless steel or Nitinol, or a rigid polymer such as PEEK. The structure may be a coil or braid, or a tube that has been laser-cut or machine-cut to provide flexibility. Additionally, the device may have radiopaque markers at the distal tip to facilitate placement of the device using fluoroscopy. In certain embodiments, the working portion of the device may be hydrophilically coated to improve advancement of the device through the vasculature.

[0032] In one embodiment, the working length of the arterial access device is configured to occlude the proximal internal carotid artery when inserted through the CCA, e.g., 10-15 cm. In an alternative embodiment, the working length of the arterial access device is a length suitable for closure with a vessel closure device, e.g., 11 cm or less. In another embodiment, the device is configured to occlude the distal internal carotid artery (ICA) when inserted through the CCA, e.g., 15-25 cm. In yet another embodiment, the arterial access device is configured to occlude the petrous, cavernous, or terminal portion of the ICA when inserted through the CCA, e.g., 20-35 cm. In this embodiment, the distal-most portion of the arterial access device, which may be about 3 to about 6 cm in length, may be configured to be more flexible to accommodate curvatures within the petrous portion of the ICA. Such additional flexibility may be achieved by using a lower durometer outer jacket material in this section. Alternatively, the wall thickness of the jacket material may be reduced and / or the density of the reinforcing layer may be modified to increase flexibility. For example, the pitch of the coils or braids may be increased, or the cut pattern of the tubing may be modified to allow for more flexibility. Additionally, the distal-most portion of the arterial access device may be tapered or stepped to a smaller diameter.

[0033] The arterial access devices described above have significantly shorter working lengths than access devices placed from a femoral artery access site. Because the distance from the femoral artery to the CCA is approximately 60-80 cm, devices utilizing a CCA access site will generally be shorter by this amount. Comparable devices designed for femoral artery access range in length from 80-95 cm for devices deployed in the cervical ICA (e.g., Concentric's balloon guide) and from 95-105 cm for devices designed to access the petrous ICA (e.g., Penumbra's Neuron 6F guide). The shorter length of the access devices disclosed herein reduces blood flow resistance through the device lumen, increasing the rate at which aspiration can occur. In this exemplary embodiment, the arterial access device is approximately 10 cm to approximately 40 cm long. In one embodiment, the arterial access device is approximately 10.5 cm long and the guide catheter is approximately 32 cm long.

[0034] Additionally, the arterial access device may include a detachable proximal extension so that the user can insert the device into the proximal port of the proximal extension and from there into the lumen of the arterial access device while minimizing radiation exposure to the user's hands. One example of a proximal extension design is described in co-pending U.S. patent application Ser. No. 12 / 540,341, filed Aug. 12, 2009, and incorporated herein by reference. U.S. patent application Ser. Nos. 12 / 633,730, 12 / 645,179, and 12 / 966,948 are also incorporated herein by reference.

[0035] Referring again to FIG. 1 , the distal catheter 2030 is configured to be inserted through the arterial access device and distal to the ICA and cerebral vessels to the location of the thrombotic occlusion 10. The length of the distal catheter 2030 is longer than the length of the arterial access device such that the distal end of the distal catheter protrudes approximately 15-25 cm from the distal opening of the arterial access device. Furthermore, the distal catheter is more flexible than the arterial access device due to the anatomy of the distal vasculature. A proximal port 2035 equipped with a hemostatic valve may be located at the proximal end of the distal catheter 2030 to allow for the introduction of devices such as microcatheters, guidewires, or thrombectomy devices while preventing or minimizing blood loss during the procedure. In some embodiments, the valve is an adjustable valve, such as a Twee-Borst valve or a rotary hemostatic valve (RHV). The hemostatic valve may be integrated into the catheter proximal adapter or may be separately attached to the proximal end of the catheter via a Luer connection.

[0036] Similar to the arterial access device, the distal catheter 2030 may be formed with two or more layers as described above. The distal catheter may be formed as described above for the working portion of the arterial access device. Additionally, the distal catheter may have a radiopaque marker at the distal tip to facilitate placement of the device using fluoroscopy. In some embodiments, the working portion of the device may be hydrophilically coated to improve advancement of the device through the vasculature. In some embodiments, the most distal portion is configured to be more flexible than the proximal portion by means such as those described above for the arterial access device.

[0037] The distal catheter 2030 has a working length configured to reach the distal ICA and cerebral vasculature when placed through the arterial access device 2010. In one embodiment, the working length is 40-80 cm. A distal catheter of this length will allow for much higher aspiration flow rates than catheters designed for transfemoral access. For example, a distal catheter configured for transfemoral access to the cerebral circulation may be 115 cm long with an inner diameter of 0.057" (inch) (DAC 057 catheter, Concentric Medical, Mountain View, Calif.), and have a flow rate of 113 ml / min for a 3.2 centipoise (cp, equivalent to blood) fluid when connected to an aspiration pump set to a vacuum of 22 in. Hg (inches of mercury). A distal catheter 2030 configured for transcervical access to the cerebral circulation from within the CCA (as described herein) may be 50 cm long with an equivalent diameter. Because flow resistance is proportional to the length of the tubing based on Poiseuille's equation for fluids passing through tubing, catheter 2030 has more than twice the flow rate of a transfemoral catheter, specifically, a flow rate of 260 ml / min for a 3.2 cp fluid when connected to an aspiration pump set to 22 in. Hg, exceeding the aspiration flow rate of the transfemoral system. The increase in aspiration rate is approximately 2.3 times the rate of aspiration. A similar increase in aspiration rate would also be seen using manual syringe aspiration or other aspiration sources. Furthermore, because a transcervical access site is much closer to many fewer turns than a transfemoral site, the catheter wall does not require as much torque strength, and thus a transcervically placed catheter 2030 can be constructed with a thinner wall construction and perform as well as or better than one placed within the target anatomy. Thinner walls result in a larger lumen, which would provide a further advantage in terms of flow rate. Because flow resistance is proportional to the fourth power of the diameter, even a small improvement in lumen area provides a significant advantage in terms of increased flow rate. In embodiments, the distal catheter may be sized to reach only the distal ICA (rather than the more distal cerebral arteries).In this embodiment, the distal catheter may have an inner diameter of 0.070" to 0.095" and a length of 25 to 50 cm. In another embodiment, the distal catheter may be sized to reach more distal cerebral arteries and may have an inner diameter of 0.035" to 0.060" and a length of 40 to 80 cm.

[0038] Similar to the arterial access device, the distal catheter may have a variable stiffness shaft. In this embodiment, the most distal portion of the distal catheter (which may be about 3 to about 6 cm in length) may be configured to be more flexible to conform to curvatures within the cerebral vasculature. This additional flexibility may be achieved by using a lower durometer outer jacket material in this portion. The shaft may have progressively stiffer sections toward more proximal portions of the shaft, with the stiffest shaft section being at the most proximal portion.

[0039] In one embodiment, an occlusion balloon 2040 may be placed on the distal catheter 2030 and can be used to occlude an artery, for example to restrict forward arterial flow or blood pressure, which would improve conditions allowing not only removal of the occlusion but also aspiration.

[0040] 1 , the distal catheter 2030 may include a proximal adapter with a Y-arm for a blood flow line 2045 (or shunt). The blood flow line 2045 has a lumen that communicates with the lumen of the distal catheter 2030. The proximal adapter further includes a proximal hemostatic valve 2035 for insertion of a guidewire, microcatheter, or other catheter. In one embodiment, the proximal adapter is permanently attached to the distal catheter 2030. In another embodiment, the proximal adapter is a female Luer connector to which a separate Twee-Borst valve with a Y-arm can be attached.

[0041] In another embodiment, the distal catheter system includes an anchor device configured to be easily navigated through the vasculature to a location distal to the cerebral occlusion. When the anchor is deployed, it may be used as a rail force and counter force to facilitate advancement of the distal catheter toward the proximal aspect of the occlusion. The example shown in FIG. 6 is a microcatheter 2505 with a distal balloon 2510. The microcatheter 2505 is placed over a guidewire 2515 through the occlusion 10, and the distal balloon 2510 is inflated. Alternatively, the microcatheter has an integrated, atraumatic guidewire tip and is advanced as a stand-alone device. The distal catheter 2030 can then utilize the shaft of the microcatheter 2505 as a rail for advancement toward the occlusion 10, as is done in the prior art. However, because the balloon 2510 is inflated, the distal end of the microcatheter 2505 anchors to the clot and / or vessel wall, providing a counter force to the advancement of the distal catheter 2030. Some of the force may be transferred to the occlusion itself, which may help remove the clot. Because the guidewire 2515 remains in place during this maneuver, access is maintained across the occlusion by the guidewire 2515 when it is necessary to re-advance the anchor (i.e., balloon 2510) and distal catheter 2030 to again attempt to remove the occlusion 10.

[0042] The atraumatic distal anchor can be a device other than a balloon. For example, other atraumatic distal anchors can include a microcatheter with a mechanically expandable tip (e.g., a braid, coil, or molly-bolt structure). The expandable tip can be configured to be sufficiently flexible and to provide sufficient force along the length of the microcatheter to reduce focal pressure against the vessel wall and minimize vessel wall trauma.

[0043] Another variation on this embodiment is a guidewire 2615 with an expandable tip 2620, such as a balloon or expandable cage or stent, as shown in FIG. 7. The guidewire 2615 is placed within the vasculature using a microcatheter and deploys when the microcatheter is retracted. The expandable portion of the guidewire 2615 device may be formed from a separate braided filament or may be cut from a single hypotube and expanded by a counterforce actuating member. For example, the proximal end of the expandable tip may be attached to the distal end of a hollow hypotube, and the distal end may be attached to a wire that runs the length of the hypotube. Pulling back on the wire will shorten the expandable tip in length and expand its diameter. Pushing the wire forward will cause the expandable tip to collapse.

[0044] Difficulties in advancing large catheters stem from a mismatch between the catheter and the internal configuration. One technique for advancing large catheters, called the tri-axial technique, involves placing a small catheter (either a microcatheter or a small-diameter distal catheter) between the larger catheter and the guidewire. However, in current systems, the small catheter has a diameter mismatch with the larger catheter, the guidewire, or both, which creates a step at the leading edge of the system as it advances through the vasculature. This step can cause difficulty in navigating highly tortuous vessels, especially in locations where side branches (e.g., the ophthalmic artery) are present. In one embodiment, as shown in FIG. 8 , a distal catheter 2030 is provided with a tapered, coaxial inner member 2652 that replaces the smaller catheter typically used. The inner member 2652 is sized and shaped to be insertable through the lumen of the distal catheter. The inner member 2652 has a tapered region with an outer diameter that forms a smooth transition between the inner diameter of the distal catheter 2030 and the outer diameter of the guidewire 2515 or microcatheter extending through the lumen of the inner member 2652. In one embodiment, the tapered dilator or inner member 2652, when placed within the distal catheter, forms a smooth transition between the distal-most tip of the larger distal catheter 2030 and the outer diameter of the guidewire 2515, which may have a diameter ranging from 0.014" to 0.018", for example. For example, the lumen diameter may be between 0.020" and 0.024". In another embodiment, the inner diameter is configured to accommodate a microcatheter having an outer diameter ranging from 0.030" to 0.040", or a 0.035" guidewire, for example, the lumen diameter may be between 0.042" and 0.044".

[0045] 9, in addition to the tapered region, the inner member 2652 includes an extension formed from a distal-most region 2653 of constant or single diameter that extends distally beyond the tapered portion of the inner member 2652. In this embodiment, the distal region 2653 of the inner member 2652 may perform some or all of the functions that the microcatheter would be useful for during a stroke intervention procedure, such as crossing an occlusion to perform distal angiograms, injecting intraarterial thrombolytic agents into a clot, or delivering a mechanical thrombectomy device such as a coil retriever or stent retriever. In this manner, the microcatheter would not need to be exchanged for a dilator for these procedures to occur.

[0046] The dilator (inner member 2652) material is sufficiently flexible and the taper is sufficiently long to provide a smooth transition between the flexibility of the guidewire and the distal catheter. This arrangement may facilitate advancing the distal catheter through tortuous anatomy to the target cerebral vasculature. In one embodiment, the dilator is configured with variable stiffness, for example, with the most distal portion formed from a soft material and the proximal portion formed from increasingly stiffer materials.

[0047] In some embodiments, the distal end of the tapered dilator includes a radiopaque marker, such as a platinum / iridium band, a tungsten, platinum, or tantalum-impregnated polymer, or other radiopaque marker. In some embodiments, the tapered dilator is configured with variable stiffness. For example, the distal segment of the dilator may be constructed of a soft material and progressively stiffer toward the proximal end. As shown in FIG. 1 , the distal catheter 2030 can itself be a catheter separate and detachable from the arterial access device. In another embodiment, as shown in FIG. 10 , the distal catheter and arterial access device are combined into a single device 2710 with a continuous lumen extending through the length of the device. The proximal section 2720 includes an arterial access sheath and a distal section 2730 that functions as the distal catheter. An occlusion balloon 2715 is located between the distal and proximal sections. The distal section 2730 is configured to be optimal for navigating the cerebral vasculature. In particular, the distal section 2730 is more flexible and tapered to a smaller diameter than the proximal section 2720 .

[0048] In another embodiment, as shown in Figures 11 and 12, the distal catheter has a second lumen that maintains guidewire access to facilitate re-advancement or exchange of the distal catheter without re-traversing the target anatomy. In the embodiment shown in Figure 11, the distal catheter has two lumens (a main lumen and a second guidewire lumen) that terminate at the distal tip. At the termination, the distal-facing surface may be angled (relative to the longitudinal axis of the catheter) to facilitate tracking of the catheter through the vasculature. In another embodiment, as shown in Figure 12, the second guidewire lumen is inside an extension 1247 that extends beyond the termination of the main lumen. The extension 1247 is the distal-most region of the distal catheter that protrudes distally beyond the opening formed by the main lumen. The extension 1247 forms a shaft with a reduced outer diameter compared to the outer diameter of the distal catheter surrounding the main lumen. The second lumen is smaller than the shaft of the main distal catheter and may be disposed within or across the occlusion when the distal end of the main lumen is positioned on the proximal surface of the occlusion. The distal end of the main lumen may similarly terminate at an angle to facilitate tracking of the device.

[0049] In yet another embodiment, the distal catheter has an expandable tip portion. When a suction device is connected to the proximal portion of the distal catheter, the expandable tip facilitates aspiration of the occlusion. The expandable tip portion may be composed of a mechanical structure, such as a braid or stent structure, which can be repeatedly opened and closed. The mechanism for opening the tip may be a pull wire that shortens the expandable portion, or an outer retention sleeve that maintains the distal portion at a small diameter but allows the distal tip to expand when retracted. The distal portion may be covered with a membrane so that vacuum can be applied to the very tip of the catheter when suction is applied, with or without the tip expanding. The expandable tip allows the catheter to maintain a low profile while tracking it to the target anatomical structure, but then expands the distal lumen area to easily capture occlusive material such as a thrombus. Once captured within the distal catheter, the thrombus may be absorbed into the suction device, or alternatively, if the catheter is no longer expanded, the thrombus may become lodged in the lumen of the distal catheter, at which point it can be removed by retracting (or withdrawing) the entire distal catheter.

[0050] In another embodiment, as shown in FIG. 13 , the distal catheter 2830 is a telescopic attachment that attaches to the distal portion of the arterial access device 2820. The distal region of the arterial access device 2820 has one or more structures that telescope distally along the longitudinal axis of the arterial access device. The structures may be telescopically folded so that they do not extend beyond the distal end of the arterial access device. When the structures telescope beyond the distal end of the arterial access device, they collectively form a continuous lumen. A tether element, such as a wire 2835, may be connected to the distal portion 2830 to expand the proximal end of the arterial access device so that telescopic actuation can be achieved from the proximal end of the arterial access device. An expandable member, such as a balloon 2815, may be positioned on the device 2820.

[0051] 14 shows an alternative embodiment in which a secondary device, such as a balloon catheter 2502, is advanced through an arterial access device 2010 into a collateral cerebral artery, such as the anterior cerebral artery (ACA). The balloon catheter 2502 includes an expandable balloon 2530 that can expand within the collateral cerebral artery to occlude the artery. As described in more detail below, occlusion of the collateral cerebral artery enhances suction and backflow through the cerebral vasculature.

[0052] Exemplary embodiments of suction and blood flow control Either or both of the arterial access device 2010 and the distal catheter 2030 may be connected to a passive or active suction source via the blood flow lines 2025, 2045 (FIG. 1) on the device. The mode of suction may vary from device to device.

[0053] In FIG. 15 , the blood flow line 2025 of the arterial access device 2010 is connected to a delivery location, such as a receptacle 3100. A suction source 3125 may be coupled to the blood flow line 2025. The receptacle 3100 and suction source 3125 may be separate or may be combined into a single device, such as a syringe. A filter 3418 and / or a check valve 3419 may be coupled to the blood flow line 2025. In FIG. 16 , the blood flow line 2045 of the distal catheter 2030 is additionally or alternatively connected to a separate suction source 3425 and a delivery location, such as a receptacle 3105. The suction source 3425 and delivery location may be combined into a single device, such as a syringe. A filter 3418 and / or a check valve 3419 may be coupled to the blood flow line 2045.

[0054] 17 shows a system in which both the arterial access device 2010 and the distal catheter 2030 are connected to the same suction source 3430 via respective blood flow lines 2025, 2045. A valve 3325 controls which device is connected to the suction source 3430. The valve can connect the suction source to one device, the other device, both devices, or another (none) device at any given time. The valve can be a three-way or four-way stopcock. Alternatively, the valve can be a simple actuation blood flow controller that selects the configuration as described above.

[0055] In some embodiments, the flow controller may facilitate control of multiple suction means through multiple devices within a single unit. This arrangement may facilitate use of the system by a single operator. The flow controller may include one or more control interfaces that a user can activate to regulate the suction applied to devices such as the arterial access device, the distal catheter, both, or others. FIG. 18 illustrates a system embodiment utilizing such a flow controller 3400. The flow controller 3400 is connected to the blood flow line 2025 of the arterial access device 2010 as well as the blood flow line 2045 of the distal catheter 2030. In this manner, the blood flow lines 2025, 2045 allow blood flow from the arterial access device 2010 and the catheter 2030, respectively, to the flow controller 3400. The controller 3400 may be connected to either or both a passive suction source 3410 and an active suction source 3420. The flow controller housing 3429 includes a control mechanism for determining how and when each device is connected to each suction source. The control mechanism may also control the level of suction from each suction source. Additionally, the controller may include a control to enable a pulsatile suction mode to facilitate collapse of the cerebral occlusion and its aspiration. The flow controller may have an interface for switching between continuous and pulsatile suction modes. The control mechanism may be designed for single-handed operation. For example, the control mechanism may be a toggle switch, a push button switch, a slider button, or the like. In one embodiment, the flow controller 3400 includes an interface, such as a single button or switch, that allows the user to quickly restore antegrade blood flow to the cerebral circulation while simultaneously deflating the occlusion balloon of the arterial access device and stopping suction.

[0056] The active suction source may be a suction pump, a regular or locking syringe, a portable aspirator, hospital suction, etc. In one embodiment, with the connection to the blood flow line closed prior to the thrombectomy step of the procedure, a locking syringe (e.g., a VacLok Syringe) is attached to the blood flow controller, and the plunger is retracted to the locked position by the user. During the procedure, when the tip of the aspirating device (either the arterial access device or the distal catheter) is near or on the surface of the occlusion, the user may open the connection to the aspirating syringe. This allows a single user to rapidly achieve maximum levels of suction, some of which are currently impossible with existing technology. In another embodiment, the suction source is a portable aspirator configured to allow aspirating and refilling without disconnecting the aspirating device. In this exemplary embodiment, the portable aspirator includes a chamber with a plunger that is moved up and down by an actuator that can be operated with one hand. The chamber includes an input and output valve so that as the plunger moves up and down, there is a continuous source of suction to and from the chamber without the need to remove and empty the chamber, as may be required with a syringe. The chamber input is connected to a catheter, and the chamber output is connected to a collection receptacle, such as a blood collection bag. In some embodiments, the suction source is configured to be used with only one hand.

[0057] One disadvantage of suction sources is that the aspirated blood is received in an external reservoir (or external container) or syringe. This blood is typically discarded at the end of the procedure, representing blood loss from the patient. Furthermore, pumps, such as centrifugal or peristaltic pumps, are known to cause damage to blood cells. While it is possible to return blood from an external reservoir to the patient, the blood is exposed to air or sits still for a period of time, risking clot formation or blood cell damage. Typically, aspirated blood is not returned to the patient to avoid the risk of thromboembolism.

[0058] FIG. 19 shows a cross-sectional view of an exemplary aspiration pump device 3250 configured to return blood to the central venous system in real time during a procedure without damaging blood cells, so that there is no reservoir where the blood sits. The pump 3250 may be connected to either or both of the arterial access device 2010 and the distal catheter 2030. The pump device 3250 includes a housing 3215 enclosing a chamber 3220 that contains a portion of the blood flow line 2025. The expandable portion 3210 of the blood flow line 2025 contained within the chamber 3220 is made from a resilient material such that it has a contracted diameter in its natural state (shown in dashed lines in FIG. 19 ) but can be configured to be reconfigured to an expanded diameter (shown in solid lines in FIG. 19 ). One or more seals 3125, such as an O-ring, seal the interface between the chamber 3220 and the blood flow line 2025. A vacuum source 3230 is connected to the chamber 3220 and is configured to be operable to alter the pressure within the chamber 3220. Two one-way check valves 3235 are located within the blood flow line 2025 on either side of the expandable portion 3210.

[0059] In operation of the pump device 3250, the vacuum source 3230 is operated to create a reduced pressure within the chamber 3220 relative to the pressure within the blood flow line lumen 3210. As shown by the solid lines in FIG. 32, the pressure difference between the chamber 3220 and the blood flow line lumen 3210 causes the expandable portion 3210 of the blood flow line 2025 to expand, increasing the volume within the chamber 3220. As controlled by the check valve 3235, this expansion pulls blood from the sheath side of the blood flow line into the expandable portion 3210, as indicated by the "inflow" arrow. The vacuum source 3230 may then be turned off to normalize the pressure within the chamber 3220, causing the expandable portion 3210 to return to its smaller, natural diameter, as shown by the dashed lines in FIG. 19. The check valve 3235 expels blood within the pre-expanded region of the blood flow line 2025 in the direction of position 3120, as indicated by the "out" arrow in Figure 19. The vacuum source 3230 may be operated to periodically vary the expandable portion 3210 between the expanded and retracted states and cooperate with the one-way check valve 3235, thereby driving blood flow through the blood flow line lumen 3210.

[0060] FIG. 20 shows a pump system 3305 that includes a pair of pump devices 3205a, 3205b, each of which is of the type shown in FIG. That is, each device 3205 includes a housing 3215 containing a chamber that contains a portion of the blood flow line 2025. The pump devices 3205a, 3205b are connected in parallel to the blood flow line 2025, such that each pump device 3205 has a blood flow line 2025 with an expandable portion 3210. The pair of pump devices 3205a, 3205b may alternate between an expanded state and a retracted state to create a relatively continuous flow state through the pump system 3305. For example, pump device 3205a may be in an expanded state while pump 3205b is in a retracted state, such that pumps 3205a, 3205b drive collectively uninterrupted blood flow through the pump system 3305.

[0061] A further advantage is that pump system 3250 or 3305, as described herein, may be used in conjunction with a passive backflow system configured to return blood to a central venous system. The two systems may share a venous return line, which is connected by a valve or other flow control device.

[0062] A passive source of suction may be a low-pressure site, such as a sheath inserted into a central vein (for venous return) or an IV (intravenous) bag placed at a vertical level that can vary depending on the degree of negative pressure desired. FIG. 21 shows an exemplary embodiment of a system 3500 using a venous return to establish passive retrograde flow to an arterial access device. The system 3500 includes an arterial access device 3510, a venous return device 3515, and a blood flow line 3520 that provides a pathway for retrograde flow from the arterial access device 3510 to the venous return device 3515. A blood flow control assembly 3525 interacts with the blood flow line 3520. The blood flow control assembly 3525 is suitable for regulating and / or monitoring retrograde flow through the blood flow line 3520. The blood flow control assembly 3525 interacts with the blood flow pathway via the blood flow line 3520 to determine the status and level of blood flow through the blood flow line.

[0063] In embodiments, as described in detail below, the arterial access device 3510 is at least partially inserted into the common carotid artery CCA and the venous return device 3515, and at least partially inserted into a venous return site such as the femoral vein or internal jugular vein. The venous return device 3515 can be inserted into the femoral vein FV via a percutaneous puncture in the groin. The arterial access device 3510 and the venous return device 3515 are connected to opposite ends of a blood flow line 3520 with connectors. The distal end of the arterial access device 3510, including the occlusion element 3529, may be positioned within the ICA. Alternatively, in situations where the ICA access is highly tortuous, it may be preferable to position the occlusion element more proximally in the common carotid artery. If blood flow through the internal carotid artery is blocked (using the occlusion element 3529), the natural pressure gradient between the internal carotid artery and the venous system will cause blood to flow retrogradely, or in a reverse direction, from the cerebral vasculature through the internal carotid artery and through the blood flow line 3520 into the venous system.

[0064] In another embodiment, the arterial access device 3510 accesses the common carotid artery (CCA) via a transcervical approach, and the venous return device 3515 accesses a venous return site other than the femoral vein, such as the internal jugular vein. In another embodiment, the system provides retrograde blood flow from the carotid artery to an external receptacle (e.g., an IV bag) rather than to the venous return site. The arterial access device 3510 connects to the receptacle via a blood flow line 3520, which communicates with a blood flow control assembly 3525. The retrograde blood flow is collected in the receptacle. Optionally, the blood can be filtered and returned to the patient. The pressure in the receptacle can be set to zero pressure (atmospheric pressure) or even lower, allowing blood to flow in the retrograde direction from the cerebral vasculature to the receptacle.

[0065] Exemplary Embodiments of a Thrombectomy Device An exemplary embodiment of a thrombectomy device for use with any of the disclosed device systems is, for example, a device as described above that is configured for transcervical placement. Specifically, the thrombectomy device has a working length that allows it to extend out of the arterial access device 2010 or distal catheter 2030 long enough to access and cross the cerebral occlusion. More specifically, the thrombectomy device has a working length of 80-120 cm.

[0066] In embodiments, a microcatheter configured for transcervical access is included as part of system 100. More specifically, a microcatheter having a working length of 100-140 cm is included in system 100. The microcatheter may be used for angiography and / or delivery of a thrombectomy device.

[0067] Further embodiments of thrombectomy devices are described below. FIG. 22 shows an enlarged side view of the distal region of an exemplary thrombectomy device 4100 formed from a self-expandable member 4112 attached to an elongated, flexible catheter 4115 extending proximally from the expandable member 4112. The expandable member 4112 is formed from a plurality of intertwined or undulating longitudinal struts arranged to form a multi-cellular structure, which may be diamond-shaped. In certain embodiments, the struts are connected to an energy source that allows acoustic energy to be applied to the struts. The expandable member 4112 is configured to transition between a reduced size and an expanded size, where the expandable member 4112 expands radially outward from a first diameter to a second diameter that is larger relative to the longitudinal axis of the catheter 4115. The expandable member 4112 may be formed from a single tube that is laser cut to the geometry to create the struts, for example, in a manner similar to the fabrication of many intravascular stents. In one embodiment, the expandable member 4112 is formed from a shape memory material, such as Nitinol. The expandable member 4112 may be comprised of the expandable member described in U.S. Patent Publication No. 20110009875, which is incorporated herein by reference in its entirety.

[0068] In use, the expandable member 4112 is advanced through the vascular anatomy via an arterial access device such as those described above. The expandable member 4112 is positioned at the thrombus site in an unexpanded state. The expandable member is then positioned at the thrombus location and transitioned to its expanded state. In certain embodiments, once the expandable member 4112 is expanded at the thrombus location, the expandable member is maintained in that position for a period of time to form a perfusion channel through the thrombus such that the resulting blood flow through the thrombus causes lysis of the thrombus. In such embodiments, the expandable member 4112 can, but need not, capture a portion of the thrombus for retrieval outside the patient's body. When a sufficient portion of the thrombus has lysed to form the desired blood flow channel through the occlusion, or when the resulting blood flow has achieved complete removal of the occlusion, the expandable member 4112 may be withdrawn into the sheath 4100 and removed from the patient. The expandable portion may capture some or all of the thrombus while being withdrawn into the sheath.

[0069] In the embodiment shown in FIG. 22 , an elongated perfusion catheter 4120 is positioned longitudinally through the expandable member 4112. The perfusion catheter 4120 has a plurality of perfusion holes communicating with an inner lumen and a source of perfusion fluid. The perfusion catheter 4120 is configured to perfuse fluid outward through the perfusion holes 4125. The perfusion holes may be used to perfuse thrombolytic agents, such as urokinase or tPA, to help dissolve blood clots. Alternatively, the perfusion holes may be used to perfuse neuroprotective agents and / or oxygenated blood.

[0070] FIG. 23 illustrates another embodiment in which an elongated mechanical member 4205 is positioned longitudinally through the expandable member 4112. The mechanical member 4205 generally extends along the longitudinal axis of the expandable member 4112. The mechanical member is configured to apply mechanical energy to the thrombus when the expandable member 4112 is positioned within the thrombus. The mechanical member 4205 can be any of a variety of mechanical members, such as a corkscrew wire or a brush. The mechanical member can be moved to apply the mechanical energy, such as by rotating or vibrating the mechanical member 4205. The embodiments of FIGS. 16 and 17 can be combined to provide irrigation and aspiration capabilities in addition to mechanical disruption capabilities.

[0071] Various other configurations may be used with or coupled to the expandable member 4112. FIG. 24 illustrates an embodiment in which a distal filter 4305 is positioned at or near the distal end of the expandable member 4112. The filter 4305 is configured to capture emboli that may be generated during removal of a thrombotic occlusion, either by natural lysis of the thrombus or mechanical retrieval of the thrombus. In the embodiment of FIG. 25, a parachute-shaped member 4405 is positioned at or near the distal end of the expandable member 4112. The embodiment of FIG. 19 includes a plurality of longitudinal struts 4605 extending from the proximal end toward the distal end of the expandable member 4112 and attached to the parachute-shaped member 4405. The struts 4605 are configured to be pushed through the thrombus when deployed within the thrombus. When pressed through the thrombus, the struts 4605 pull the parachute-shaped members 4405 around the thrombus, capturing it, after which the device 4100 can be withdrawn, removing the thrombus from the artery.

[0072] 26, an expandable expansion member 4505, e.g., an expansion balloon, is disposed within the expandable member 4112. The expansion member 4505 may be expanded to enlarge the thrombotic occlusion and compress the expandable member 4112. Once the expansion member has been expanded, the expandable member, now engaged with the clot, may be pulled back to remove the thrombus from the artery.

[0073] FIG. 27 shows another embodiment of a thrombectomy device comprising an elongate element 4705 positioned at the distal end of a distal catheter 4710. The elongate element 4705 has an irregular shape along its longitudinal axis, such as a spiral or wavy shape. Alternatively, the elongate element is slidably positioned within the distal catheter 4710. The elongate element 4705 may be formed from a spring material, such as stainless steel or nitinol, so that it can retract into the distal catheter 4710 when crossing the clot. After crossing, the catheter 4710 is retracted to expose the elongate element 4705 and allow it to assume its irregular shape. The elongate element is positioned at the site of the thrombus and may be manipulated, such as vibrating, rotating, undulating, spinning, or moving back and forth, to apply mechanical energy to the thrombus and fragment it. The distal catheter 4710 is connected to a suction source to aspirate the thrombus as it is mechanically disrupted by the elongated elements 4705 .

[0074] In the embodiment of FIG. 28 , an elongate catheter 4805 is sized and shaped to be positioned within the thrombus. The catheter 4805 includes perfusion holes 4810 that can be used to spray perfusion fluid onto the thrombus with sufficient force to fragment the thrombus. The elongate catheter 4805 may be delivered through a separate distal catheter 4820. The distal catheter 4820 may be connected to a suction source to aspirate the thrombus as it is fluidly fragmented by the perfusion fluid from the elongate catheter 4805. The distal end of the catheter 4805 may include an expandable occlusion element 4815 to prevent the perfusion fluid or fragmented thrombus from migrating downstream.

[0075] 29, a catheter 4900 includes dual lumens running parallel along the length of the catheter 4900. The dual lumens include an access lumen 4920 for deployment of an interventional device, such as a thrombectomy device or stentriever, and an irrigation lumen 4930 for delivering irrigation fluids, thrombolytic agents, or for aspirating thrombotic material.

[0076] It should be recognized that other mechanical thrombectomy catheters may be used in a similar manner to the vascular access and retrograde flow systems described above. Mechanical thrombectomy devices may include variations of the aforementioned thrombectomy devices, such as coil-tipped retrievers, stent retrievers, expandable cages, wire or filament loops, graspers, brushes, etc. These clot retrievers may include aspiration lumens to reduce the risk of embolic debris causing ischemic complications. Alternatively, thrombectomy devices may include clot disruption elements, such as fluid vortices, ultrasonic or laser energy elements, balloons, etc., along with flushing and aspiration to remove the clot. Some exemplary devices and methods are described in the following U.S. patents and patent application publications, all of which are incorporated herein by reference: U.S. Patent No. 6,730,104, U.S. Patent No. 6,663,650, U.S. Patent No. 6,428,531, U.S. Patent No. 6,379,325, U.S. Patent No. 6,481,439, U.S. Patent No. 6,929,632, U.S. Patent No. 5,938,645, U.S. Patent No. 6,824,545, U.S. Patent No. 6,679,893, U.S. Patent No. 6,685,722, U.S. Patent No. 6,436,087, U.S. Patent No. 5,794,629, U.S. Patent Application Publication No. 20080177245, U.S. Patent Application Publication No. 20090299 393, U.S. Patent Application Publication No. 20040133232, U.S. Patent Application Publication No. 20020183783, U.S. Patent Application Publication No. 20070198028, U.S. Patent Application Publication No. 20060058836, U.S. Patent Application Publication No. 20060058837, U.S. Patent Application Publication No. 20060058838, U.S. Patent Application Publication No. 20060058838, and U.S. Patent Application Publication No. 20030212384, and U.S. Patent Application Publication No. 20020133111.

[0077] A major drawback of current thrombectomy devices is the need to recross the occlusion with a guidewire and microcatheter if the device fails to clear enough of the occlusion to restore proper blood flow and further attempts are needed to clear the occlusion. Currently, single-lumen microcatheters are used to deliver thrombectomy devices. The microcatheter is positioned over a guidewire, and the guidewire is removed to deliver the thrombectomy device. When clearing the occlusion, both the microcatheter and device are pulled back, losing access across the occlusion. Therefore, if a removal attempt is unsuccessful or incomplete and further attempts are needed, the guidewire and microcatheter must be recrossed across the occlusion. As mentioned above, the extra step of recrossing is time-consuming and introduces the risk of distal vessel injury. As shown in FIG. 30 , an embodiment of this disclosure is a microcatheter 4200 that includes at least two lumens: one lumen for a guidewire 2515 and a second for delivery of a thrombectomy device 4100, such as a stentriever or coil retriever. The presence of a second lumen for the guidewire would add an exterior profile to the microcatheter over a microcatheter with only a single lumen. However, the time and risk reduction offered by the second guidewire lumen can be advantageous. Furthermore, for transcervical use, the guidewire and / or catheter walls may be scaled down to less than traditional wall thicknesses to reduce the overall increase required to add the extra lumen.

[0078] Exemplary Embodiments of a Perfusion Device In certain embodiments, the system may include a means for perfusing the cerebral vasculature and ischemic brain tissue distal to the thrombotic occlusion, for example, via a perfusion catheter delivered through the arterial access device 2010 to a site distal to the thrombotic occlusion 10. The perfusion catheter is adapted to deliver a perfusion solution to the desired location. The perfusion solution may include, for example, autologous arterial blood from the blood flow line of the passive retrograde flow circuit 3500 or from another artery, an oxygenated solution, or other neuroprotective agents. Additionally, the perfusion solution may be hypothermic to cool the brain tissue, another strategy shown to minimize brain trauma during ischemic periods. The perfusion catheter may also be used to deliver a bolus of intra-arterial thrombolytic agent simulating thrombolytic therapy. Typically, thrombolytic therapy will take 1-2 hours to clear the occlusion after the bolus is delivered. Mechanical thrombectomy will also take 1-2 hours to successfully reopen the blocked artery. Distal perfusion of the ischemic region can minimize the level of brain trauma during stroke treatment procedures. Embodiments of distal perfusion means are described below.

[0079] FIG. 31 shows a perfusion catheter 3600 positioned across a thrombotic occlusion 10, allowing perfusion distal to the occlusion. In one embodiment, the catheter 3600 is positioned over a guidewire placed through a lumen within the catheter. The lumen will serve as both the guidewire lumen and the perfusion lumen. Once placed, the guidewire may be removed to maximize the throughspace available for perfusion. Alternatively, the guidewire lumen and perfusion lumen may be two separate lumens within the catheter, such that the guidewire remains in place within the guidewire lumen without interfering with the perfusion lumen during perfusion. A perfusion exit hole 3615 communicates with the perfusion lumen and is located in the distal region of the catheter 3600. This perfusion lumen may be connected to a perfusion source, such as an infusion pump or syringe, and may be used to perfuse a perfusion solution, such as a neuroprotective agent, and / or oxygenated blood, such as the patient's own arterial blood, through the perfusion outlet holes 3615, as shown in FIG. 32 by arrow P (representing the flow of perfusion solution ejected from the catheter 3600). Alternatively, the catheter 3600 may be positioned relative to the occlusion 10 during bolus administration of thrombolysis such that the perfusion outlet holes 3615 are initially positioned just proximal to or within the thrombotic occlusion 10. The catheter can then be repositioned so that at least some of the perfusion outlet holes 3615 are located distal to the occlusion 10 to provide distal perfusion with blood or equivalent fluid to the ischemic penumbra. The perfusion catheter may also be used in conjunction with mechanical or aspiration thrombectomy, as described above. The catheter may be positioned through a lumen of the access device 2010 or the distal catheter 2030. The catheter may be placed side-by-side with the intraluminal mechanical thrombectomy means or may be coaxial with the mechanical thrombectomy device.

[0080] FIG. 32 shows another embodiment of a perfusion catheter 3600 with a perfusion lumen 3610 communicating with a side hole 3615 and / or end opening 3616 for perfusion fluid and a second lumen 3612 for pressure monitoring. The pressure monitoring lumen 3612 is closed at its distal-most end 3613. A side hole 3614 to the lumen 3612 is located proximal to the distal-most end 3613 for measuring perfusion pressure. The catheter 3600 can include an expandable occlusion element, such as an occlusion balloon, but is shown without an expandable occlusion element. The occlusion element may be positioned either distal or proximal to the side hole 3615. In one embodiment, the perfusion source may be controlled with perfusion pressure measurements to maintain a perfusion pressure of less than 200 mm Hg. In one embodiment, the perfusion flow rate is controlled to maintain perfusion in the range of about 50 ml / min to about 250 ml / min.

[0081] In an alternative embodiment, as shown in FIG. 33 , a distal perfusion catheter 3700 includes an occlusion balloon 3705, with perfusion outlet holes 3715 positioned distal and / or proximal to the occlusion balloon 3705. As with the previous embodiment, the perfusion catheter 3700 may be used in conjunction with a recanalization therapy, such as a thrombectomy device, aspiration, or intra-arterial administration of a thrombolytic agent. The catheter 3700 is placed within the vasculature such that the occlusion balloon 3705 is positioned distal to the occlusion 10. The catheter 3700 may be configured to perfuse an area distal to the balloon 3705 with blood or an equivalent fluid and to perfuse an area proximal to the balloon 3705 with a thrombolytic agent. In this regard, as shown in FIG. 34 , the catheter 3700 may include separate perfusion lumens 3720, 3725 communicating with separate perfusion outlet holes. Instead, as shown in Figure 35, the distal and proximal perfusion outlet holes connect to the same perfusion lumen 3630, which is used to infuse both the distal and proximal regions of the occlusion balloon with blood or an alternative perfusion solution. Not shown in either Figures 34 or 35 is a separate lumen for inflation and deflation of the occlusion balloon 3705. This lumen may be embedded in the wall of the catheter.

[0082] In another embodiment, as shown in FIG. 36, the expandable occlusion device 3705 is a dilatation balloon that can exert an expansion force on the thrombus while the catheter 3700 perfuses the distal vasculature.

[0083] The perfusion catheter may also provide perfusion to aid in clot removal. FIG. 37 shows a proximal perfusion catheter (proximal perfusion catheter) 3800 deployed distal to the occlusion via the arterial access device 2010. The proximal perfusion catheter 3800 includes an expandable occlusion element 3829, such as an occlusion balloon. The proximal perfusion catheter 3800 further includes one or more perfusion outlet holes 3820 proximal to the occlusion element 3829. The perfusion outlet holes 3820 communicate with an internal perfusion lumen within the perfusion catheter 3800 for perfusion of fluid outflowing through the perfusion outlet holes 3820. With further reference to FIG. 37 , the proximal perfusion catheter 3800 is deployed into the vasculature via the arterial access device such that the occlusion element 3829 of the perfusion catheter is positioned and expanded distal to the thrombus 10, and the perfusion outlet holes 3820 are positioned proximal to and distal to the occlusion element 3829 and thrombus 10. Such an arrangement provides back pressure to aid in the removal of the thrombus 10. Additionally, the occlusion element 3829 serves as distal embolic protection. Any of a variety of perfusion fluids may be used, including, for example, oxygenated blood, neuroprotective agents, thrombolytic agents, and other fluids, and may be adjusted to a desired temperature. The arterial access device 2010 can be used for aspiration in the arrangement shown in FIG. 37. The arterial access device 2010 may include an occlusion balloon 2020 and passive or active aspiration means. The perfusion catheter facilitates the removal of the thrombus through the arterial access device 2010, the blood flow line 2025, and out of the patient's body.

[0084] Alternatively, as shown in FIG. 38 , the proximal perfusion catheter 3800 may be delivered through the distal catheter 2030. If suction is initiated through the distal catheter 2030 and perfusion is initiated through the proximal perfusion catheter 3800, there is a reverse pressure gradient that helps remove the thrombus 10 from the blood vessel into the lumen of the distal catheter 2030. The arterial access device 2010 and the distal catheter 2030 may be aspirated simultaneously. Alternatively, suction may be applied sequentially between the arterial access device 2010 and the distal catheter 2030. For example, the distal catheter 2030 can be aspirated when positioned as shown in FIG. 38 . The distal catheter 2030 can then be retracted into the arterial access device 2010 and suction can be applied from the arterial access device.

[0085] In addition to applying pressure distal to the occlusion, the perfusion fluid from the proximal perfusion catheter 3800 can supply blood to small blood vessels (perforators) originating within or just proximal to the occlusion. The shaft of the perfusion catheter 3800 may also be used as a rail or conduit for delivering therapeutic devices such as a stentriever or thrombectomy device.

[0086] In one embodiment, the perfusion lumen and the guidewire lumen are two separate lumens, configured, for example, as shown in FIG. 32. In an alternative embodiment, the perfusion lumen of the perfusion catheter 3800 also functions as the guidewire lumen. In such an arrangement, a valve is desirably located at the distal end opening of the perfusion / guidewire lumen. When the guidewire is pushed distally out of the distal end opening of the guidewire lumen, the guidewire opens the valve. When the guidewire is retracted proximally back into the lumen, the valve automatically closes. In this way, after the guidewire is retracted, the valve seals the distal end opening of the lumen. The valve can also serve as a pressure relief valve, opening to relieve pressure when the perfusion pressure becomes too high.

[0087] Figures 39A-39D illustrate a typical use of the proximal perfusion catheter 3800. Figure 39A shows an enlarged view of a guidewire 3912 positioned across a thrombus 10 in a cerebral artery. In Figure 39B, the distal region of the perfusion catheter 3800 (via the guidewire 3912) is positioned across the thrombus 10, with an unexpanded occlusion element 3829 positioned distal to the thrombus 10. The guidewire 3912 protrudes from the distal end of the guidewire lumen of the perfusion catheter 3800. In Figure 39C, the guidewire is not shown because it has been retracted into the guidewire lumen of the perfusion catheter 3800. If the guidewire lumen also serves as the perfusion lumen for the perfusion catheter 3800, a distal valve 3916 (e.g., a duckbill valve) at the distal end of the guidewire / perfusion lumen automatically closes so that the lumen is now available for perfusion via the perfusion outlet hole 3820, as shown in FIG. 34C at arrow P. When the occlusion element 3829 is unexpanded (as shown in FIG. 39C), the perfusion outlet hole 3820 is available for distal perfusion. In FIG. 39D, the expandable occlusion element 3829 has been expanded in the artery. The perfusion outlet hole 3820 is then available for perfusion proximal to the occlusion element 3829, as shown by arrow P1 in FIG. 39D.

[0088] The perfusion catheters 3600, 3800 may include a pressure monitoring element. In one embodiment, the pressure monitoring element is a dedicated internal lumen of the perfusion catheter 3600, 3800 that is filled with fluid and connected to a pressure transducer at the proximal end of the perfusion catheter. A pressure transducer on the catheter itself may also be used. Alternatively, a pressure measuring guidewire may be inserted through the lumen of the perfusion catheter 3600, 3800 to the location where pressure is to be monitored.

[0089] An alternative means for cerebral perfusion involves cerebral retroperfusion, as described by Frazee et al. This embodiment involves selective cannulation via the internal jugular vein and occlusion of the transverse sinus, followed by blood infusion into brain tissue via the superior sagittal sinus during the treatment of ischemic stroke. The following articles describe cerebral retroperfusion and are incorporated herein by reference in their entirety: Frazee, JG and X. Luo (1999) "Retrograde transvenous perfusion," Crit Care Clin 15(4):777-88, vii; Frazee, JG, X. Luo et al. (1998) "Retrograde transvenous neuroperfusion: a back door treatment for stroke," Stroke 29(9):1912-6. This perfusion, in addition to providing protection for the brain tissue, will provide a retrograde flow gradient in the cerebral arteries. The retroperfusion component used with the retrograde flow system 100 not only helps capture embolic debris within the retrograde flow line during recanalization of the thrombotic occlusion 10, but also provides oxygen to the brain tissue.

[0090] It should be appreciated that other perfusion catheters or systems may be used with system 100, such as those described in U.S. Patent No. 6,435,189 and U.S. Patent No. 6,295,990, which are incorporated herein by reference in their entireties.

[0091] Exemplary Methods and Devices for Transcervical Vascular Closure Any type of closure element, including a self-closing element, a suture-based closing element, or a hydrostatic seal element, may be deployed at or around the penetration in the common carotid artery wall prior to withdrawal of the arterial access device 2010 or introducer sheath 2110 (procedural sheath) at the end of the procedure. U.S. Patent No. 20100042118, entitled "Suture Delivery Device," and U.S. Patent No. 20100228269, entitled "Vessel Closure Clip Device," describe exemplary closure devices and methods and are incorporated herein by reference in their entireties.

[0092] The closure elements may be deployed at or near the beginning of the procedure in a step called "pre-closure," or the closure elements may be deployed as the sheath is withdrawn. In one embodiment, the vascular closure means is a suture-based vascular closure device. A suture-based vascular closure device can place one or more sutures across the vascular access site so that when the ends of the sutures are tied after sheath removal, one or more stitches (or sutures) provide hemostasis at the access site. The sutures can be applied prior to insertion of a procedural sheath through the arteriotomy or after removal of the sheath from the arteriotomy. If a pre-closure step is used, the device can maintain temporary hemostasis at the arteriotomy after suture placement, except before and during procedural sheath placement, and can also maintain temporary hemostasis after procedural sheath withdrawal, except before the sutures are tied. Some suture-based vessel disclosure devices are described in US Pat. No. 6,562,052, US Pat. No. 7,001,400, and US Pat. No. 7,004,952, which are incorporated herein by reference in their entireties.

[0093] In one embodiment, the system includes an ultrasound probe element that, when used with an ultrasound imaging system, is configured to identify a desired site for carotid artery access and determine its suitability for percutaneous puncture, e.g., to confirm the vessel is free of vascular disease. The probe may also visualize surrounding anatomical structures, such as the internal jugular vein, to ensure that access can be achieved without involving these other structures. Additionally, the probe may be used to visualize the access site after vessel closure to confirm that hemostasis has been achieved. If necessary, the probe may be used to provide localized compression to the puncture site as needed to ensure hemostasis. For example, after vessel closure, the probe is used to image the closure site. If blood is seen to be overflowing from the site, the probe is depressed to compress the site. The user periodically releases pressure on the probe to assess whether hemostasis has been achieved. If not, pressure is applied again. If hemostasis is achieved, the probe may be removed.

[0094] <Typical Usage> As shown in FIG. 1 , the arterial access device 2010 is introduced transcervically directly into the patient's common carotid artery (CCA). This can be done via percutaneous puncture or direct cutdown. In the case of a puncture, ultrasound imaging can be used to accurately make the initial arterial puncture. The arterial access device 2010 is threaded through the vasculature so that the distal tip is positioned in the proximal or distal cervical, petrous, or cavernous portion of the common carotid artery or internal carotid artery (ICA). A detachable proximal extension may be used to place the arterial access device 2010 under fluoroscopy without exposing the user's hands to radiation. Exemplary embodiments of the detachable proximal extension are described in U.S. Patent Application No. 12 / 834,869, filed July 12, 2010, and are incorporated herein by reference.

[0095] Once the arterial access device is positioned, a diagnostic angiogram may be performed via a microcatheter placed through the arterial access device. The microcatheter may be for angiographic injection both proximal and distal to the occlusion. Diagnostic angiograms are performed throughout the procedure to determine the progress of clearing the occlusion(s).

[0096] If the arterial suction device has an occlusion balloon, the balloon may be inflated at this stage to apply suction to the arterial access device. Because the tip of the suction device is some distance proximal to the occlusion, suction force cannot be applied directly to the occlusion. However, sometimes this proximal suction may be useful in removing some or all of the occlusion. Once suction from the access device is complete, the occlusion balloon may be deflated so that antegrade blood flow can resume in the artery.

[0097] The distal catheter 2030 is placed through the arterial access device and positioned so that the distal tip reaches the site of the occlusion. Optionally, a coaxial system of devices including a guidewire, microcatheter, and distal catheter 2030 is threaded together through the arterial access device 2010 and advanced toward the cerebral occlusion. Alternatively, a tapered dilator with or without a microcatheter tip may be used in place of a microcatheter. Alternatively, the microcatheter and guidewire may be placed inside the tapered dilator. The detachable proximal extension, if used, may be removed before introduction of the telescopic device, or the device may be inserted through the detachable proximal extension. The microcatheter or tapered dilator and guidewire are then advanced to approach and cross the cerebral occlusion. The microcatheter or dilator may be used to perform angiograms of the cerebral circulation proximal or distal to the occlusion. The microcatheter may also be used as a rail for advancing the distal catheter.

[0098] Typically, a large distal catheter is selected that can be safely navigated to the occlusion, maximizing the force and luminal area for aspiration of the occlusion. Suction is then initiated through the distal catheter. This can be done manually, with a suction pump, or other suction source, or via the flow controller described above. If the thrombus is too large or deeply embedded in the vasculature to remove the occlusion with suction alone, additional steps are taken to remove the occlusion. A thrombectomy device may be deployed through the arterial access device to remove the clot. During clot retrieval, passive or active suction may be applied through the arterial access device to minimize or eliminate the amount of distal emboli.

[0099] If the distal catheter does not reach the occlusion, or if it becomes necessary to reach a second occlusion further distally after removal of the first occlusion, a second, smaller diameter distal catheter may be inserted through the first distal catheter and positioned at the occlusion site. Alternatively, the first distal catheter may be removed and replaced with the second distal catheter. A guidewire and / or microcatheter may be placed through the first distal catheter to facilitate the exchange. Once the desired site is reached, suction may be initiated through the second catheter as described above, or additional devices may be inserted to aid in removing the occlusion.

[0100] If it is difficult to navigate a distal catheter of the desired size to a position just proximal to the clot, a device can be deployed distal to the clot and expanded to act as an anchor to aid in the advancement of the distal catheter, as shown in FIG. 6 or FIG. 7. If desired, a second distal catheter can be used in a telescoping manner to provide support for the first distal catheter to access the proximal aspect of the occlusion. Alternatively, a tapered dilator, as shown in FIG. 8, can be used in addition to or instead of a microcatheter to facilitate navigation of the distal catheter. The arterial access device 2010 and distal catheter 2030 can be connected to passive or active suction means, as shown in FIGS. 15-17, or to a blood flow controller 3400, as shown in FIG. 18. In one embodiment, the arterial access device 2010 is connected to passive suction and the distal catheter 2030 is connected to active suction. In another embodiment, both devices are connected to active suction. During the procedure, the user can open and close connections to passive and / or active suction sources as desired. For example, once the distal catheter 2030 is positioned at the proximal aspect of the clot, active suction may be initiated to apply suction to the occlusion in order to remove it. If additional suction steps are desired using a locked syringe, the syringe may be detached, emptied, reattached, and relocked for additional suction.

[0101] In another embodiment, the microcatheter is used to deliver a thrombectomy device, such as a coil or stentriever, into or beyond the occlusion. The device is then pulled toward the distal catheter, aided by suction on the distal catheter, to remove the occlusion. The occlusion is then pulled back into the arterial access device using the distal catheter, thrombectomy device, and / or microcatheter. In yet another embodiment, the microcatheter has two lumens, as shown in Figures 11 and 12, so that a guidewire remains across the occlusion when the microcatheter and / or thrombectomy device is pulled proximally to remove the occlusion.

[0102] At any time during the procedure, a balloon on the arterial access device may be inflated at this stage to reduce forward arterial pressure on the occlusion. The inflated balloon may improve the stability of the arterial access in the vessel and provide better support for device advancement through the arterial access device. Additionally, the arterial access device may be connected to the passive or active suction described above to provide embolic protection without compromising collateral blood flow to the patient's ischemic penumbra. This may be achieved by selective periods of retrograde flow, cessation of blood flow, and antegrade blood flow, e.g., retrograde flow initiated during periods when the occlusion is being pulled toward and / or into the guide catheter. Multiple devices or device sizes may be used to remove one or more occlusions, as needed. At the end of the procedure, the arterial access catheter may be exchanged for a shorter introducer sheath, and a vessel closure device may be used to achieve hemostasis at the access site. Ultrasound may again be used, this time to confirm and / or ensure hemostasis. If appropriate, the ultrasound probe may be used to apply pressure to the access site until hemostasis is achieved.

[0103] In a variation of this procedure, the arterial access device is inserted through an introducer sheath that has been previously inserted into the CCA. An example of this arrangement is shown in Figure 2. In this scenario, if the device becomes blocked and suction slows or stops, the arterial access device may be removed during the procedure and cleaned on the table, or, if necessary, exchanged for a different size or type of catheter without compromising arterial access. Furthermore, there is no need to change the sheath at the end of the procedure before utilizing a vessel closure device. The introducer sheath may incorporate a detachable proximal extension to limit radiation exposure to the user's hands during the procedure. If used, the proximal extension may be removed prior to closure of the access site with the vessel closure device.

[0104] In yet another embodiment, the system may be used to administer intra-arterial thrombolytic therapy, for example, through a side arm in the arterial access device 2010. For example, thrombolytic therapy may be administered to the thrombotic occlusion 10 through the arterial access device 2010 or through the distal catheter 2030. In another embodiment, the system may be used to administer intra-arterial thrombolytic therapy via a microcatheter inserted into the arterial access device 2010. The microcatheter is delivered to the site of the thrombotic occlusion 10 to administer the thrombolytic agent. Thrombolytic therapy may be administered in conjunction with or instead of mechanical thrombectomy or aspiration.

[0105] In a further embodiment, the system is used to provide distal protection and / or perfusion during the procedure. In this embodiment, a perfusion catheter is inserted through the arterial access device 2010 or the distal catheter 2030, positioned across the lumen, and inflated at a point distal to the occlusion. The perfusion catheter is connected to an infusion pump to perfuse oxygenated blood or perfusion solution into the ischemic brain through the distal opening of the perfusion catheter. In one embodiment, the perfusion catheter is a balloon-tipped catheter. The balloon is inflated at a location distal to the occlusion. The balloon functions to prevent emboli from advancing distally during removal or recanalization of the occlusion. The perfusion catheter may also be connected to a flush source to perfuse proximal to the occlusion balloon through a proximal port on the perfusion catheter. This procedure essentially provides backpressure on the occlusion and may help to remove it.

[0106] If a carotid stenosis is also present, requiring treatment either before or after treatment of the cerebral occlusion, an angioplasty balloon or stent may be deployed within the stenosis via the introducer sheath. If embolic protection is desired during intervention of the carotid stenosis, the introducer sheath may have an occlusion balloon and a connection to a retrograde flow line, as shown in FIG. 3, and the CAS procedure may be performed under retrograde embolic protection, as described in co-pending U.S. patent application Ser. No. 12 / 176,250 (incorporated herein by reference). The introducer sheath is then used to place an arterial access device within the ICA. Alternatively, the introducer sheath may have an opening and two occlusion balloons, as shown in FIG. 4, to allow balloon angioplasty or stent placement at the carotid stenosis and subsequent introduction of a device (such as a distal catheter) into the ICA and cerebral circulation to treat the cerebral occlusion.

[0107] Although this specification contains many specifics, these should not be construed as limitations on the scope of the invention as claimed or that may be claimed, but as describing features particular to particular embodiments. Multiple features described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, even if certain features are described above as functioning in a combination and are initially claimed as such, one or more features from the claimed combination may sometimes be excluded from that combination, and the claimed combination may be described as a subcombination or a variation of the subcombination. Similarly, although operations are illustrated in the figures in a particular order, it should not be understood that such operations need to be performed in the particular order illustrated, or in a sequential order, or that all of the illustrated operations must be performed to achieve desirable results.

[0108] Although various method and device embodiments have been described in detail herein with reference to certain variations, it should be recognized that other variations, embodiments, uses, and combinations thereof are also possible, and therefore the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

1. a transcervical access sheath adapted for direct introduction into a common carotid artery through an opening in the artery, the opening being located above the patient's clavicle and below a bifurcation point where the common carotid artery branches into an internal carotid artery and an external carotid artery, the transcervical access sheath having an internal lumen; a distal catheter sized and shaped for axial insertion through the lumen of the transcervical access sheath so that the distal catheter can be inserted into a cerebral artery through the transcervical access sheath, the distal catheter having a lumen defined by an inner diameter; an elongate inner member sized and shaped for axial insertion through the lumen of the transcervical access sheath, the inner member having an inner lumen; a guidewire configured to be insertable into the cerebral artery through the lumen of the inner member, 1. A system of devices for treating an occlusion in a cerebral artery of a patient, wherein the inner member has an outer diameter configured to form a smooth transition between the inner diameter of the distal catheter and the outer diameter of the guidewire.

2. 10. The system of claim 1, wherein the distal tapered region of the inner member has an outer diameter that tapers in size toward the outer diameter of the guidewire.

3. the inner member includes a first tapered region having an outer diameter that tapers toward the outer diameter of the guidewire and a second, distal-most region having a substantially constant outer diameter; The system of claim 1 , wherein the guidewire protrudes from the distal-most region.

4. further comprising a blood flow line connected to the arterial access sheath; 10. The system of claim 1, wherein the blood flow line provides a pathway for blood to flow from the arterial access sheath to a return site.

5. 5. The system of claim 4, further comprising a flow controller connected to the shunt and adapted to regulate blood flow through the shunt.

6. 10. The system of claim 1, further comprising a radiopaque marker at the distal end of the distal catheter.

7. a transcervical access sheath adapted for direct introduction into the common carotid artery through an opening in the artery, the opening being located above the patient's clavicle and below a bifurcation where the common carotid artery bifurcates into the internal carotid artery and the external carotid artery, the transcervical access sheath having an internal lumen; 1. A system of devices for treating an occlusion in a patient's cerebral artery, comprising: a distal catheter sized and shaped for axial insertion through the lumen of the transcervical access sheath so that the distal catheter can be inserted into the cerebral artery through the transcervical access sheath, the distal catheter having a first lumen and a smaller second lumen, the distal-most portion of the second lumen being positioned within an extension that projects distally beyond a distal opening formed by the first lumen.

8. 8. The system of claim 7, wherein the extension defines a shaft having a reduced outer diameter compared to the outer diameter of the distal catheter about a main lumen.

9. further comprising a blood flow line connected to the arterial access sheath; 8. The system of claim 7, wherein the blood flow line provides a pathway for blood to flow from the arterial access sheath to a return site.

10. 10. The system of claim 9, further comprising a flow controller coupled to the shunt and adapted to regulate blood flow through the shunt.

11. 8. The system of claim 7, wherein the distal end of the distal catheter has a distal-facing surface disposed at an angle relative to a longitudinal axis of the distal catheter.

12. a transcervical introducer sheath adapted for direct introduction into a common carotid artery through an opening in the artery, the opening being located above the patient's clavicle and below a bifurcation point where the common carotid artery bifurcates into an internal carotid artery and an external carotid artery, the transcervical introducer sheath having an internal lumen; a blood flow line connected to the introducer sheath, the blood flow line providing a path for blood to flow from the introducer sheath to a return site; a hemostatic valve in a proximal region of the introducer sheath that provides access to the lumen of the introducer sheath while preventing blood loss; a guide catheter sized and shaped for insertion through the hemostatic valve and into the lumen of the introducer sheath so as to provide access to the cerebral artery through the interior of the guide catheter.

13. further comprising a blood flow line connected to the guide catheter; 13. The system of claim 12, wherein the blood flow line provides a pathway for blood to flow from the guide catheter to a return site.

14. The system of claim 12, further comprising an occlusion device coupled to the introducer sheath.

15. The system of claim 12, further comprising an occlusion device coupled to the guide catheter.

16. 13. The system of claim 12, further comprising a distal catheter sized and shaped for axial insertion through the lumen of the guide catheter so that the distal catheter can be inserted into a cerebral artery.

17. forming an opening in the common carotid artery; inserting a transcervical access sheath into the common carotid artery through the opening and deploying a distal end of the sheath into the common carotid artery or the internal carotid artery, the access sheath having an internal lumen; inserting a first distal catheter into the lumen of the access sheath; positioning a distal end of the first distal catheter in the cerebral artery adjacent the occlusion; applying suction through the first distal catheter to capture the occlusion at the distal end of the first distal catheter; and retracting the distal end of the first distal catheter into the access sheath to retract the occlusion into the access sheath.

18. the access sheath includes an expandable occlusion element; 18. The method of claim 17, further comprising expanding the occlusion element to occlude the common or internal carotid artery.

19. 18. The method of claim 17, wherein the access sheath is inserted through the opening without a separate introducer sheath to provide access to the common carotid artery.

20. further comprising inserting the introducer sheath through the opening such that the introducer sheath provides access to the common carotid artery; and then inserting the access sheath through the introducer sheath into the common carotid artery.

21. 18. The method of claim 17, wherein the distal tip of the first distal catheter includes a tapered dilator configured to form a smooth transition between the distal tip and a guidewire over which the first distal catheter can be positioned.

22. the tapered dilator includes a tapered section and an extension distal to the tapered section; 22. The method of claim 21, wherein the extension has a substantially constant outer diameter along its entire length.

23. 18. The method of claim 17, further comprising deploying a thrombectomy device through the access sheath into the occlusion and using the thrombectomy device to at least partially remove the occlusion.

24. the extension is positioned across the occlusion; 24. The method of claim 23, further comprising deploying a thrombectomy device through a lumen of the tapered dilator distal to the occlusion and using the thrombectomy device to at least partially remove the occlusion.

25. 24. The method of claim 23, wherein suction is applied to a distal catheter when the thrombectomy device is used to remove the occlusion.

26. 18. The method of claim 17, further comprising deploying a second distal catheter through the access sheath into the occlusion.

27. 26. The method of claim 25, further comprising deploying the second distal catheter through the lumen of the first distal catheter.

28. 26. The method of claim 25, further comprising removing the first distal catheter from the access sheath before deploying the second distal catheter.

29. 18. The method of claim 17, further comprising using ultrasound imaging to assist in creating an opening in the wall of the common carotid artery.

30. 18. The method of claim 17, further comprising using a vessel closure device to close the opening in the wall of the common carotid artery.

31. 18. The method of claim 17, further comprising using ultrasound imaging to help ensure hemostasis in closing the opening.

32. The method further comprising the step of drawing aspirate through the access sheath.

18. The method of claim 17.

33. the access sheath further includes a blood flow line attached to the access sheath at a location between the distal end and the proximal end of the access sheath; 18. The method of claim 17, further comprising connecting a blood flow line to a return site so that fluid can flow from the access sheath through the blood flow line to the return site.

34. 34. The method of claim 33, wherein the return site is a receptacle.

35. 34. The method of claim 33, wherein the return site is a venous return site.

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