Occlusion sheath configured for percutaneous vascular access

Abstract

Systems and methods disclosed herein are configured for use in vascular and / or neural interventional procedures. The systems and methods enable safe and rapid access to the carotid artery, including percutaneous access, and further access to the brain or intracranial artery, to introduce an interventional device, such as for the treatment of a disease condition. The methods and devices may include vascular access and retrograde blood flow systems.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] Pursuant to 35 U.S.C. §119(e), this application claims priority to U.S. Provisional Patent Application Serial No. 63 / 391,067, filed on July 21, 2022, entitled “Occlusion Sheath Configured for Percutaneous Vascular Access,” the entire contents of which are incorporated herein by reference. Background Art

[0003] The present invention relates generally to medical methods and devices. More particularly, the present invention relates to methods, systems and devices for accessing and treating the carotid vasculature, and optionally establishing retrograde blood flow during carotid stenting and other procedures.

[0004] The present invention also relates to methods and systems for accessing and treating the cerebral arterial vasculature, such as for treating stroke, intracranial atherosclerotic disease (ICAD), transient ischemic attack (TIA), acute ischemic stroke (AIS), tandem lesions, embolization of ruptured and unruptured intracranial and extracranial aneurysms, chronic occlusions, and other disease conditions of the neurovascular system. Summary of the invention

[0005] The present invention discloses methods and devices for vascular and / or neurological interventional procedures. The methods and devices enable safe and rapid access to the carotid arteries, including percutaneous access, and further access to the brain or intracranial arteries to introduce interventional devices, such as for the treatment of stroke and / or other disease conditions. The methods and devices include vascular access and retrograde blood flow systems.

[0006] In one aspect, a system for accessing and treating a carotid artery is disclosed, the system comprising: an outer guide sheath configured to be delivered percutaneously into the carotid artery; an inner catheter movably positioned within the outer guide sheath, the inner catheter having an expandable element positioned on a distal region of the inner catheter, wherein the inner catheter comprises a lumen extending between a proximal end and a distal end and adapted to receive blood flow from a common carotid artery, the outer guide sheath and the inner catheter being adapted to be introduced together into the common carotid artery, the expandable element being adapted to expand and occlude the common carotid artery; and a locking collar positioned on a proximal region of the outer guide sheath, the locking collar being configured to rotate around an outer wall of the outer guide sheath, wherein the locking collar has a There is a first set of threads on the inner wall of the locking collar, wherein the first set of threads engages a second set of threads on the outer wall of the inner catheter, and wherein rotation of the locking collar causes the first set of threads to engage the second set of threads and lock the position of the inner catheter relative to the outer guide sheath; wherein the inner catheter is movably positioned within the outer guide sheath between a first position and a second position, wherein in the first position, the outer guide sheath is positioned relative to the outer guide sheath so that a portion of the outer guide sheath covers and constrains the expandable element in a contracted state, and in the second position, the outer guide sheath does not constrain the expandable element, and wherein when the inner catheter is in the first position, the locking collar is aligned with the second set of threads.

[0007] Other aspects, 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 DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A is a schematic diagram of a retrograde blood flow system including a flow control assembly in which an arterial access device is introduced into the common carotid artery via a transcarotid approach and a venous return device is communicated with the internal jugular vein.

[0009] Figure 1B is a schematic diagram of a retrograde blood flow system in which an arterial access device is placed into the common carotid artery via a transcarotid approach and a venous return device is connected to the femoral vein.

[0010] Figure 1C is a schematic diagram of a retrograde blood flow system in which an arterial access device is placed into the common carotid artery via a transfemoral approach and a venous return device is connected to the femoral vein.

[0011] Figure 1D is a schematic diagram of a retrograde blood flow system in which the retrograde flow is collected in an external container.

[0012] Figure 2A is an enlarged view of a carotid artery with the carotid artery occluded with an occluding element on a sheath and connected to a reverse flow shunt, and an interventional device, such as a stent delivery system or other working catheter introduced into the carotid artery via an arterial access device.

[0013] Figure 2B is an alternative system in which the carotid artery is occluded with a separate external occlusion device and connected to a reverse flow shunt, and an interventional device, such as a stent delivery system or other working catheter, is introduced into the carotid artery via an arterial access device.

[0014] Figure 3 is an alternative system in which the carotid artery is connected to a reverse flow shunt and an interventional device, such as a stent delivery system or other working catheter, is introduced into the carotid artery via an arterial access device and the carotid artery is occluded with a separate occlusion device.

[0015] Figure 4 A diagram of normal cerebral circulation including the loop of Williams is shown.

[0016] Figure 5 The vascular system in the patient's neck is shown, including the common carotid artery CCA, the internal carotid artery ICA, the external carotid artery ECA, and the internal jugular vein IJV.

[0017] Fig. 6A An arterial access device that can be used in the methods and systems of the present invention is shown.

[0018] Figure 6B An additional arterial access device configuration is shown having a distal end with a reduced diameter.

[0019] Fig. 7A and Figure 7B Shows that Fig. 6A A tube used together with a sheath.

[0020] Figure 7C An embodiment of a sheath stop is shown.

[0021] Fig.7D Shown positioned on the sheath Figure 7C The sheath stopper.

[0022] Fig. 8A An additional arterial access device configuration having an expandable occlusive element is shown.

[0023] Figure 8B An additional arterial access device configuration is shown having an expandable occlusive element and a distal end with a reduced diameter.

[0024] Fig.9A and Fig. 9B Additional embodiments of arterial access devices are shown.

[0025] Fig. 9C and Fig.9D An embodiment of a valve on an arterial access device is shown.

[0026] FIG. 10A to FIG. 10C and Fig.11An embodiment of a venous return device that may be used in the methods and systems of the present invention is shown.

[0027] Fig.12 The system of FIG. 1 is shown including a flow control assembly.

[0028] Figure 13 to Figure 14 Embodiments of variable flow resistance components that may be used in the methods and systems of the present invention are shown.

[0029] FIG. 15A to FIG. 15C A schematic diagram of an embodiment of a sheath 1505 configured for percutaneous access and occlusion of a blood vessel, such as an artery, is shown.

[0030] Fig.16A and Fig. 16B A schematic diagram illustrating a distal region of an embodiment of a sheath configured for percutaneous access and occlusion of a blood vessel.

[0031] Fig.17A and Fig. 17B A schematic diagram illustrating the distal region of an embodiment of a sheath 1705 configured for percutaneous access and occlusion of a blood vessel.

[0032] Fig.18A An embodiment of a sheath having a distal umbrella element is shown.

[0033] Fig.18B Show Fig.18A Cross-sectional view of the sheath.

[0034] Fig.19A and Fig.19B Another embodiment of an umbrella member on a sheath is shown.

[0035] Fig. 20A and Fig. 20B The distal region of the sheath is shown with an expandable element, such as a balloon.

[0036] Fig.21A and Fig.21B Another embodiment of a sheath including an expandable balloon is shown.

[0037] FIG. 22A to FIG. 22C An embodiment of a sheath including an expandable balloon integrated into the outer wall of the sheath is shown.

[0038] FIG. 23A to FIG. 23B The proximal hub of the sheath is shown configured to control the tensioned configuration of the balloon.

[0039] Fig.24A and Fig. 24B Alternative mechanisms that may be coupled to the sheath for controlling the tensioned configuration of the balloon are shown.

[0040] Fig.25A and Fig.25BAn embodiment of a sheath system including a balloon sheath integrated with a guide sheath is shown.

[0041] FIG. 26A to FIG. 26C Another embodiment of a sheath system is shown that includes a balloon sheath integrated with an introducer sheath.

[0042] Fig. 27 and Fig.28 Schematic diagrams and cross-sectional views of embodiments of sheaths are shown.

[0043] FIG. 29A to FIG. 30B An embodiment of a sheath positioned in a blood vessel is shown. DETAILED DESCRIPTION

[0044] The disclosed methods, devices and systems establish and promote retrograde or reverse blood flow blood circulation in the carotid bifurcation region to limit or prevent the release of emboli into the cerebrovascular system, particularly into the internal carotid artery. In non-limiting examples, the methods can be used for interventional procedures such as stenting and angioplasty, atherectomy, which is performed using open surgical techniques or using percutaneous techniques such as modified Seldinger techniques or micropuncture techniques through a transcarotid approach or a transfemoral approach to the common carotid artery. Any of a variety of interventions can be used in conjunction with the systems and methods described herein, including treatment of stroke, intracranial atherosclerotic disease (ICAD), transient ischemic attack (TIA), acute ischemic stroke (AIS), tandem lesions, embolization of ruptured and unruptured intracranial and extracranial aneurysms, chronic occlusions, intravascular lithotripsy (IVL), shock wave intravascular lithotripsy (IVL) and other disease conditions of the neurovascular system.

[0045] Entering the common carotid artery (such as Figure 5 ) is established by placing an access sheath or other tubular access cannula into the arterial lumen, typically with the distal end of the sheath positioned proximal to the intersection or bifurcation B from the common carotid artery to the internal and external carotid arteries. A percutaneous version of the sheath may have an occlusive member at the distal end, such as a compliant occlusive balloon. A catheter or guidewire with an occlusive member, such as a balloon, may be placed through the access sheath and positioned in the proximal external carotid artery ECA to inhibit entry of emboli, but occlusion of the external carotid artery is generally not necessary. A second return sheath is placed in the venous system, such as the internal jugular vein IJV or the femoral vein FV. The arterial access and venous return sheaths are connected to create an external arteriovenous shunt.

[0046] Retrograde blood flow is established and adjusted to meet the patient's requirements. Blood flow through the common carotid artery can be occluded with an external vascular ring or tape, a vascular clamp, an internal occlusive member such as a balloon, or other type of occlusive device. When blood flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system will cause blood to flow retrograde or in the opposite direction from the cerebral vascular system through the internal carotid artery and the shunt to the venous system.

[0047] Alternatively, the venous sheath can be eliminated and the arterial sheath can be connected to an external collection reservoir or container. The reverse blood flow can be collected in this container. If necessary, the collected blood flow can be filtered and then returned to the patient during or at the end of the operation. The pressure of the container can be open to atmospheric pressure, resulting in a pressure gradient that causes blood to flow back from the cerebral vascular system to the container, or the pressure of the container can be negative pressure.

[0048] Alternatively, to achieve or enhance reverse blood flow from the internal carotid artery, blood flow from the external carotid artery may be blocked, typically by deploying a balloon or other occlusive element in the external carotid artery just above (ie, distal to) the bifurcation within the internal carotid artery.

[0049] Although the procedures and protocols described below will be particularly directed to carotid stenting, it should be understood that the methods described herein for accessing the carotid arteries may also be used for angioplasty, arteriotomy, and any other interventional procedures that may be performed in the carotid system, such as at a location near the bifurcation between the internal and external carotid arteries. In addition, it should be understood that some of these access, vessel closure, and embolic protection methods will be applicable to other vascular interventional procedures, for example, the treatment of acute stroke.

[0050] The present invention includes a number of specific aspects for improving the performance of carotid access protocols. At least some of these individual aspects and improvements may be performed alone or in combination with one or more of the improvements to facilitate and enhance the performance of specific interventions in the carotid system.

[0051] Figure 1AA first embodiment of a retrograde blood flow system 100 is shown, which is suitable for establishing and promoting retrograde or reverse blood flow blood circulation in the carotid bifurcation region to limit or prevent the release of emboli into the cerebrovascular system, particularly into the internal carotid artery. The system 100 interacts with the carotid artery to provide retrograde blood flow from the carotid artery to a venous return site, such as the internal jugular vein (or to another return site, such as another great vein or an external container in an alternative embodiment). The retrograde blood flow system 100 includes an arterial access device 110, a venous return device 115, and a shunt 120, which provides a pathway for retrograde blood flow from the arterial access device 110 to the venous return device 115. A flow control assembly 125 interacts with the shunt 120. The flow control assembly 125 is suitable for regulating and / or monitoring retrograde blood flow from the common carotid artery to the internal jugular vein, as described in more detail below. Flow control assembly 125 interacts with the blood flow path through shunt 120, which may be external to the flow path, internal to the flow path, or both. Arterial access device 110 is at least partially inserted into the common carotid artery CCA, and venous return device 115 is at least partially inserted into a venous return site, such as the internal jugular vein IJV, as described in more detail below. Arterial access device 110 and venous return device 115 are coupled to shunt 120 at connection locations 127a and 127b. When blood flow through the common carotid artery is obstructed, the natural pressure gradient between the internal carotid artery and the venous system causes blood to flow retrograde or reverse RG (from the cerebral vascular system) to the cerebral vascular system. Figure 2A ) flows through the internal carotid artery and shunt 120 to the venous system. Flow control assembly 125 regulates, enhances, assists, monitors and / or otherwise regulates retrograde blood flow.

[0052] exist Figure 1AIn an embodiment, the arterial access device 110 enters the common carotid artery CCA via a transcarotid approach. Transcarotid access provides a short and non-tortuous path from the vascular access point to the target treatment site, thereby reducing the time and difficulty of the operation, for example, compared with a transfemoral approach. In one embodiment, the arterial distance from the arteriotomy to the target treatment site (as measured across the artery) is 15 cm or less. In one embodiment, the distance is between 5 and 10 centimeters. Additionally, the access route reduces the risk of emboli generated by navigating in a diseased, angled or tortuous aortic arch or common carotid artery anatomy. At least a portion of the venous return device 115 is placed in the internal jugular vein UV. In one embodiment, transcarotid access to the common carotid artery is achieved percutaneously via an incision or puncture in the skin, and the arterial access device 110 is inserted through the incision or puncture. If an incision is used, the length of the incision may be about 0.5 cm. An occluding element 129, such as an expandable balloon, can be used to occlude the common carotid artery CCA at a position proximal to the distal end of the arterial access device 110. The occlusive element 129 may be located on the arterial access device 110 or it may be located on a separate device. In an alternative embodiment, the arterial access device 110 accesses the common carotid artery CCA via a direct surgical transcarotid approach. In the surgical approach, a tourniquet 2105 may be used to occlude the common carotid artery. The tourniquet 2105 is shown in phantom to indicate that it is a device used in an alternative surgical approach.

[0053] In another embodiment, Figure 1B As shown, arterial access device 110 enters the common carotid artery CCA via a transcarotid approach, while venous return device 115 enters a venous return site other than the jugular vein, such as a venous return site consisting of the femoral vein FV. Venous return device 115 can be inserted into a central vein, such as the femoral vein FV, via percutaneous puncture in the groin.

[0054] In another embodiment, Figure 1C As shown, the arterial access device 110 enters the common carotid artery via a femoral artery approach. According to the femoral artery approach, the arterial access device 110 approaches the CCA via a percutaneous puncture to the femoral artery FA, ​​such as in the groin, and enters the target common carotid artery CCA upward along the aortic arch AA. The venous return device 115 can be connected to the jugular vein JV or the femoral vein FV.

[0055] Figure 1DYet another embodiment is shown, in which the system provides retrograde blood flow from the carotid artery to an external container 130, rather than to a venous return site. The arterial access device 110 is connected to the container 130 via a shunt 120, which is in communication with a flow control assembly 125. The retrograde blood flow of blood is collected in the container 130. If necessary, the blood can be filtered and then returned to the patient. The pressure of the container 130 can be set to zero pressure (atmospheric pressure) or even lower, thereby causing blood to flow backward from the cerebral vascular system to the container 130. Optionally, in order to achieve or enhance reverse blood flow from the internal carotid artery, blood flow from the external carotid artery can be blocked, which is usually performed by deploying a balloon or other occlusive element in the external carotid artery just above the bifurcation within the internal carotid artery. Figure 1D The arterial access device 110 is shown deployed with a CCA in a transcarotid approach, however it should be understood that the outer container 130 can also be used with the arterial access device 110 in a transfemoral approach.

[0056] refer to Figure 2A Magnified view of the middle carotid artery, a therapeutic or interventional device, such as a stent delivery system 135 or other working catheter, can be introduced into the carotid artery via an arterial access device 110 or a percutaneous sheath, as described in detail below. The stent delivery system 135 can be used to treat plaque P, such as deploying a stent into the carotid artery. Figure 2A The arrow RG in the figure indicates the direction of retrograde blood flow. Figure 2B As shown, in an alternative embodiment, the clamp element is used to occlude the artery.

[0057] Figure 3 An alternative embodiment is shown in which the occluding element 129 can be introduced into the carotid artery on a second sheath 112 that is separate from the distal sheath 605 of the arterial access device 110. The second or "proximal" sheath 112 can be adapted for insertion into the common carotid artery in a proximal or "downward" direction away from the cerebral vasculature. The second proximal sheath can include an inflatable balloon 129 or other occluding element, generally as described above. The distal sheath 605 of the arterial access device 110 can then be placed in the common carotid artery distal to the second proximal sheath and generally oriented in a distal direction toward the cerebral vasculature. By using separate occluding and access sheaths, the size of the arteriotomy required to introduce the access sheath can be reduced.

[0058] Anatomical description

[0059] Collateral cerebral circulation

[0060] The Williams Circle CW is the main arterial anastomosis trunk of the brain, in which all the main arteries supplying blood to the brain, i.e., the two internal carotid arteries (ICA) and the vertebrobasilar system are connected. Blood is transported to the brain from the Williams Circle by the anterior cerebral artery, the middle artery, and the posterior cerebral artery. This communication between the arteries makes collateral circulation through the brain possible. Blood flow through alternative routes is made possible, thereby providing a safety mechanism in the case of occlusion of one or more blood vessels supplying blood to the brain. In most cases, even when an obstruction occurs somewhere in the arterial system (e.g., when the ICA is ligated, as described herein), the brain can continue to receive sufficient blood supply. The blood flow flowing through the Williams Circle ensures sufficient cerebral blood flow by redistributing blood to multiple paths on the deprived side.

[0061] It is believed that the collateral potential of the Williams circle depends on the presence and size of its constituent vessels. It should be understood that there may be considerable anatomical differences between individuals in these vessels, and many of the vessels involved may be diseased. For example, some people lack one of the communicating arteries. If these people are blocked, the collateral circulation will be impaired, resulting in ischemic events and potential brain damage. In addition, the autoregulatory response to reduced perfusion pressure may include enlarging collateral arteries in the Williams circle, such as the communicating arteries. This compensatory mechanism occasionally requires adjustment time before the collateral circulation can reach a level that supports normal function. This autoregulatory response can occur in the space of 15 to 30 seconds and can only compensate within a certain range of pressure and flow declines. Therefore, transient ischemic attacks may occur during the adjustment period. Very high retrograde flow rates over extended periods of time can lead to a situation where the patient's brain cannot obtain sufficient blood flow, resulting in patient intolerance, which manifests as neurological symptoms or in some cases transient ischemic attacks.

[0062] Figure 4 The normal cerebral circulation and formation of the Williams circle CW are depicted. The aorta AO gives off the brachiocephalic artery BCA, which branches into the left common carotid artery LCCA and the left subclavian artery LSCA. The aorta AO further gives off the right common carotid artery RCCA and the right subclavian artery RSCA. The left and right common carotid arteries CCA give off the internal carotid artery ICA, which branches into the middle cerebral artery MCA, the posterior communicating artery PcoA and the anterior cerebral artery ACA. The anterior cerebral artery ACA delivers blood to some parts of the frontal lobe and the striatum. The middle cerebral artery MCA is a large artery with tree-like branches that bring blood flow to the entire side of each hemisphere of the brain. The left and right posterior cerebral arteries PCA originate from the basilar artery BA and deliver blood to the back of the brain (occipital lobe).

[0063] Anteriorly, the circle of Williams is formed by the anterior cerebral artery ACA and the anterior communicating artery ACoA connecting the two ACAs. Two posterior communicating arteries PCoA connect the circle of Williams to two posterior cerebral arteries PCA, which branch from the basilar artery BA and complete the circle posteriorly.

[0064] The common carotid artery CCA also gives rise to the external carotid artery ECA, which branches extensively to supply most structures of the head, with the exception of the brain and orbital contents. The ECA also helps supply structures in the neck and face.

[0065] Carotid bifurcation

[0066] Figure 5 An enlarged view of the relevant vascular system in the patient's neck is shown. The common carotid artery CCA branches into the internal carotid artery ICA and the external carotid artery ECA at the bifurcation B. The bifurcation is located approximately at the level of the fourth cervical vertebra. Figure 5 A plaque P formed at the bifurcation B is shown.

[0067] As discussed above, the arterial access device 110 can access the common carotid artery CCA via a transcarotid approach. According to the transcarotid approach, the arterial access device 110 is inserted into the common carotid artery CCA at an arterial access location L, which can be, for example, a surgical incision or puncture in the wall of the common carotid artery CCA. The distance D between the arterial access location L and the bifurcation B is typically about 5 to 7 cm. When the arterial access device 110 is inserted into the common carotid artery CCA, it is not desirable for the distal tip of the arterial access device 110 to contact the bifurcation B because this may disrupt the plaque P and cause the generation of embolic particles. In order to minimize the possibility of the arterial access device 110 contacting the bifurcation B, in one embodiment, only about 2-4 cm of the distal region of the arterial access device is inserted into the common carotid artery CCA during surgery.

[0068] Each side of the common carotid artery is wrapped in a layer of fascia called the carotid sheath. This sheath also encloses the internal jugular vein and vagus nerve. The anterior portion of the sheath is the sternocleidomastoid muscle. Transcarotid access to the common carotid artery and internal jugular vein, either percutaneously or surgically, can be performed just above the clavicle, between the two heads of the sternocleidomastoid muscle and carefully through the carotid sheath to avoid the vagus nerve.

[0069] At the upper end of this sheath, the common carotid artery bifurcates into the internal and external carotid arteries. The internal carotid artery continues upward without branching until it enters the skull to supply the retina and brain. The external carotid artery branches to supply the scalp, face, eyes, or other superficial structures. Several facial and cranial nerves weave together in front and behind the artery. Additional neck muscles may also cover the bifurcation. During the carotid endarterectomy, these nerves and muscle structures can be dissected and pushed aside to access the carotid bifurcation. In some cases, the carotid bifurcation is closer to the level of the mandible, where access is more challenging and there is less space available to separate it from the various nerves that should be preserved. In these cases, the risk of accidental nerve injury may be increased, and open endarterectomy may not be a good option.

[0070] Retrograde blood flow system

[0071] As discussed, the retrograde blood flow system 100 includes an arterial access device 110, a venous return device 115, and a shunt 120 that provides a pathway for retrograde blood flow from the arterial access device 110 to the venous return device 115. The system also includes a flow control assembly 125 that interacts with the shunt 120 to regulate and / or monitor retrograde blood flow through the shunt 120. Exemplary embodiments of components of the retrograde blood flow system 100 are now described.

[0072] Arterial Access Devices

[0073] Fig. 6A An exemplary embodiment of an arterial access device 110 is shown, which includes a distal sheath 605, a proximal extension 610, a flow line 615, an adapter or Y-connector 620, and a hemostatic valve 625. The arterial access device may also include a dilator 645 having a tapered tip 650 and an introducer guidewire 611. The arterial access device is used with the dilator and the introducer guidewire to access a blood vessel. The features of the arterial access device can be optimized for transcarotid access. For example, the design of the access device components can be optimized to limit potential damage to the blood vessel due to sharp angle insertion, allow non-invasive and safe sheath insertion, and limit the length of the sheath, sheath dilator, and introducer guidewire inserted into the blood vessel. The arterial access device 110 may include any embodiment of the percutaneous sheath described herein.

[0074] The distal sheath 605 is suitable for introduction through an incision or puncture in the wall of the common carotid artery, which can be an open surgical incision or, for example, a percutaneous puncture established using the Seldinger technique. The sheath length can be in the range of 5 to 15 cm, typically 10 cm to 12 cm. The inner diameter is typically in the range of 7 Fr (1 Fr = 0.33 mm) to 10 Fr, typically 8 Fr. In particular, when the sheath is introduced through a transcarotid approach, above the clavicle but below the carotid bifurcation, it is desirable that the sheath 605 has a high degree of flexibility while maintaining circumferential strength to resist kinking and buckling. Therefore, the distal sheath 605 can be circumferentially enhanced, such as by braid, spiral band, spiral wire, cutting tubing, etc., and has an inner liner so that the reinforcement structure is sandwiched between the outer jacket layer and the inner liner. The inner liner can be a low friction material, such as PTFE. The outer jacket can be one or more of a group of materials, including Pebax, thermoplastic polyurethane or nylon. In one embodiment, the reinforcement structure or material and / or outer jacket material or thickness may vary over the length of the sheath 605 to vary its flexibility along the length. In an alternative embodiment, the distal sheath is adapted to be introduced into the femoral artery, such as in the groin, via percutaneous puncture and up the aortic arch AA into the target common carotid artery CCA.

[0075] The distal sheath 605 may have a stepped or other morphology with a distal region 630 of reduced diameter, as shown in FIG. Figure 6B As shown. The distal region 630 of the sheath can be sized for insertion into the carotid artery, typically having an inner diameter in the range of 2.16 mm (0.085 inches) to 2.92 mm (0.115 inches), wherein the remaining proximal region of the sheath has a larger outer diameter and lumen diameter, wherein the inner diameter is typically in the range of 2.794 mm (0.110 inches) to 3.43 mm (0.135 inches). The larger lumen diameter of the proximal region minimizes the overall flow resistance of the sheath. In one embodiment, the reduced diameter distal segment 630 has a length of approximately 2 cm to 4 cm. The relatively short length of the reduced diameter distal segment 630 allows the segment to be positioned in the common carotid artery CCA via a transcarotid approach, wherein the risk that the distal end of the sheath 605 will contact the bifurcation B is reduced. In addition, the reduced diameter segment 630 also allows the size of the arteriotomy used to introduce the sheath 605 into the artery to be reduced, while minimizing the impact on the level of flow resistance. Furthermore, the reduced diameter distal section may be more flexible and thus better conform to the lumen of a blood vessel.

[0076] Reference again Fig. 6A, the proximal extension 610 of the elongated body has an inner cavity continuous with the inner cavity of the sheath 605. The cavity can be combined by a Y-connector 620, which also connects the cavity of the streamline 615 to the sheath. In the assembled system, the streamline 615 is connected to the retrograde shunt 120 (Figure 1) and forms its first leg. The proximal extension 610 may have a length sufficient to space the hemostatic valve 625 away from the Y-connector 620 adjacent to the percutaneous or surgical insertion site. By spacing the hemostatic valve 625 away from the percutaneous insertion site, the physician can introduce the stent delivery system or other working catheter into the proximal extension 610 and the sheath 605 while being outside the fluoroscopic field when performing fluoroscopic fluoroscopy. In one embodiment, the distance from the most distal intersection of the proximal extension with the sheath 605 (such as, at the hemostatic valve) to the proximal end of the proximal extension is about 16.9 cm. In one embodiment, the proximal extension has an inner diameter of 0.125 inches and an outer diameter of 0.175 inches. In one embodiment, the proximal extension has a wall thickness of 0.025 inches. For example, the inner diameter can range from, for example, 0.60 inches to 0.150 inches, and the wall thickness can range from 0.010 inches to 0.050 inches. In another embodiment, the inner diameter can range from, for example, 0.150 inches to 0.250 inches, and the wall thickness can range from 0.025 inches to 0.100 inches. The size of the proximal extension can vary. In one embodiment, the proximal extension has a length in the range of about 12-20 cm. In another embodiment, the proximal extension has a length in the range of about 20-30 cm.

[0077] In one embodiment, the distance along the sheath from the hemostatic valve 625 to the distal tip of the sheath 605 is in the range of about 25 to 40 cm. In one embodiment, the distance is in the range of about 30 to 35 cm. In the case where the system configuration allows a 2.5 cm sheath to be introduced into the artery and the distance in the artery from the arteriotomy site to the target site is between 5 and 10 cm, the system enables the distance from the hemostatic valve 625 (the location of the interventional device introduced into the sheath) to the target site to be in the range of about 32.5 cm to 42.5 cm, between 32 and 43 cm. This distance is about one-third of the distance required by the prior art.

[0078] The flush line 635 can be connected to the side of the hemostatic valve 625 and can have a stopcock 640 at its proximal or distal end. The flush line 635 can allow for the introduction of saline, contrast fluid, etc. during surgery. The flush line 635 can also allow for pressure monitoring during surgery. For example, a dilator 645 with a tapered distal end 650 can be provided to facilitate introduction of the distal sheath 605 into the common carotid artery. The dilator 645 can be introduced through the hemostatic valve 625 so that the tapered distal end 650 extends through the distal end of the sheath 605, such as in Fig. 7A645. Dilator 645 may have a central lumen to accommodate a guidewire. Typically, a guidewire is first placed into the vessel, and the dilator / sheath combination is advanced over the guidewire as it is introduced into the vessel.

[0079] Optionally, a sheath stopper 705, such as in the form of a tube, may be provided that is coaxially received on the exterior of the distal sheath 605, also as shown. Fig. 7A As shown. The sheath stopper 705 is configured to act as a sheath stopper to prevent the sheath from being inserted too deeply into a blood vessel. The sheath stopper 705 is sized and shaped to be positioned on the sheath body 605 so that it covers a portion of the sheath body 605 and leaves a distal portion of the sheath body 605 exposed. The sheath stopper 705 may have a flared proximal end 710 that engages the adapter 620, and a distal end 715. Optionally, the distal end 715 may be beveled, such as Figure 7B As shown. Sheath stopper 705 can be used for at least two purposes. First, the length of sheath stopper 705 limits the introduction of sheath 605 to the exposed distal portion of sheath 605, such as Fig. 7A As shown, the insertion length of the sheath is limited to the exposed distal portion of the sheath. In one embodiment, the sheath stopper limits the exposed distal portion to a range between 2 and 3 cm. In one embodiment, the sheath stopper limits the exposed distal portion to 2.5 cm. In other words, the sheath stopper can limit the insertion of the sheath into the artery to a range between about 2 and 3 cm or to 2.5 cm. Secondly, the sheath stopper 705 can engage the pre-deployed puncture closure device (if present) disposed in the carotid wall to allow the sheath 605 to be withdrawn without removing the closure device. The sheath stopper 705 can be made of a transparent material so that the sheath body can be clearly seen below the sheath stopper 705. The sheath stopper 705 can also be made of a flexible material, or the sheath stopper 705 includes a hinged section with increased flexibility, so that it allows the sheath to be bent in place as needed once it is inserted into the artery. The sheath stopper can be plastically bendable so that it can be bent into a desired shape so that it maintains the shape when released by the user. The distal portion of the sheath stopper can be made of a harder material, and the proximal portion can be made of a more flexible material. In one embodiment, the harder material has a hardness of 85A, and the more flexible section has a hardness of 50A. In one embodiment, the harder distal portion is a sheath stopper 705 of 1 to 4 cm. The sheath stopper 705 can be removed from the sheath so that if the user desires a larger sheath insertion length, the user can remove the sheath stopper 705, cut the length of (the sheath stopper) shorter, and reassemble the sheath stopper 705 to the sheath so that a larger length of insertable sheath length is extended from the sheath stopper 705.

[0080] Figure 7CAnother embodiment of a sheath stopper 705 is shown positioned adjacent a sheath 605 having a dilator 645 positioned therein. Figure 7C The sheath stopper 705 can be deformed from a first shape, such as a straight shape, to a second shape different from the first shape, wherein the sheath stopper maintains the second shape until a sufficient external force acts on the sheath stopper to change its shape. For example, the second shape can be a non-straight, curved, or other contoured or irregular shape. For example, Figure 7C A sheath stop 705 is shown having multiple bends as well as straight sections. Figure 7C Only one example is shown, but it will be appreciated that the sheath retainer 705 may be shaped to have any number of bends along its longitudinal axis. Fig.7D The sheath stopper 705 is shown positioned on the sheath 605. The sheath stopper 705 has a greater rigidity than the sheath 605, so that the sheath 605 assumes a shape or contour that conforms to the contoured shape of the sheath stopper 705.

[0081] The sheath stopper 705 can be shaped according to the angle at which the sheath is inserted into the artery and the depth of the artery or the size of the patient. This feature reduces the force of the sheath tip in the vessel wall, particularly when the sheath is inserted into the vessel at a steep angle. The sheath stopper can be bent or otherwise deformed into a shape that helps to orient the sheath coaxially with the artery to be entered, even when the angle of entry into the arteriotomy is relatively steep. The sheath stopper can be shaped by the operator before the sheath is inserted into the patient. Alternatively, the sheath stopper can be shaped and / or reshaped after the sheath is inserted into the artery.

[0082] In another embodiment, Fig.9A As shown, the sheath stopper 705 includes a distal base or flange 710 that is sized and shaped to distribute the force of the sheath stopper over a larger area of ​​the vessel wall, thereby reducing the risk of vessel damage or accidental insertion of the sheath stopper into the vessel through an arteriotomy. The flange 710 can have a circular or other non-invasive shape that is large enough to distribute the force of the sheath stopper over a large area of ​​the vessel wall. In one embodiment, the flange is inflatable or mechanically expandable. For example, an arterial sheath and sheath stopper can be inserted into the surgical area through a small puncture in the skin and then expanded before the sheath is inserted into the artery.

[0083] The sheath stopper may include one or more cutouts or indentations 720 along the length of the sheath stopper, which are patterned in a staggered manner so that the indentations increase the bendability of the sheath stopper while maintaining axial strength to allow the forward force of the sheath stopper to abut against the arterial wall. The indentations may also be used to facilitate fixing the sheath to the patient via sutures to hinder the sheath from moving out. The sheath stopper may also include a connector element 730 on the proximal end, which corresponds to a feature on the arterial sheath so that the sheath stopper may be locked or unlocked from the arterial sheath. For example, the connector element is a hub with a slot 740 that is roughly L-shaped, and the slot 740 corresponds to a pin 750 on the hub to create a bayonet-mounted connection. In this way, the sheath stopper may be securely attached to the hub to reduce the possibility of the sheath stopper being accidentally removed from the hub unless unlocked from the hub.

[0084] The distal sheath 605 can be configured to establish a curved transition from a generally anterior-posterior approach above the common carotid artery to a generally axial luminal direction within the common carotid artery. Arterial access through the wall of the common carotid artery, whether direct surgical resection or percutaneous access, may require an entry angle that is generally larger than other arterial entry sites. This is because the common carotid artery insertion site is closer to the treatment site (i.e., the carotid bifurcation) than other entry points. A larger entry angle is needed to increase the distance from the insertion site to the treatment site to allow the sheath to be inserted at a sufficient distance without causing the distal tip of the sheath to reach the carotid bifurcation. For example, the sheath insertion angle for access through the carotid artery is generally 30-45 degrees or even larger, while the sheath insertion angle for accessing the femoral artery may be 15-20 degrees. Therefore, the sheath must adopt a generally larger bend than the introducer sheath, so that it will not be kinked, and it will not cause excessive force on the relative arterial wall. In addition, it is expected that the sheath tip will not abut or contact the arterial wall in a manner that limits the blood flow in the sheath after insertion. The sheath insertion angle is defined as the angle between the luminal axis of the artery and the longitudinal axis of the sheath.

[0085] Another sheath configuration includes a curved dilator inserted into a straight but flexible sheath so that the dilator and sheath bend during insertion. The sheath is flexible enough to conform to the anatomy after the dilator is removed.

[0086] In one embodiment, the sheath has built-in puncture capability and an atraumatic tip similar to the tip of a guidewire. This eliminates the need for needle and wire exchange currently used for arterial access based on micropuncture techniques, thus saving time, reducing blood loss and requiring less surgeon skill.

[0087] Fig. 8A Another embodiment of an arterial access device 110 is shown. This embodiment is similar to the arterial access device 110 except that the distal sheath 605 includes an occluding element 129 for occluding blood flow through, for example, the common carotid artery. Fig. 6AThe embodiments shown in are substantially the same. If the occluding element 129 is an inflatable structure, such as a balloon, the sheath 605 may include an inflation chamber communicated with the occluding element 129. The occluding element 129 may be an inflatable balloon, but it may also be an inflatable cuff, a conical or other circumferential element that flares outward to engage the inner wall of the common carotid artery to block flow therethrough, a coated braid, a slotted tube that expands radially when axially compressed, or a similar structure that can be deployed mechanically, etc. In the case of balloon occlusion, the balloon may be compliant, non-compliant, elastomeric, enhanced, or have various other properties. In one embodiment, the balloon is an elastomeric balloon that is tightly received on the outside of the distal end of the sheath before inflation. When inflated, the elastomeric balloon can expand and conform to the inner wall of the common carotid artery. In one embodiment, the elastomeric balloon is capable of expanding to a diameter at least twice that of the undeployed configuration, often capable of deploying to a diameter at least three times that of the undeployed configuration, and more preferably at least four times that of the undeployed configuration or greater.

[0088] like Figure 8B As shown, the distal sheath 605 with the occluding element 129 may have a stepped or other morphology with a distal region 630 of reduced diameter. The distal region 630 may be sized for insertion into the carotid artery, wherein the remaining proximal region of the sheath 605 has a larger outer diameter and lumen diameter, wherein the inner diameter is typically in the range of 2.794 mm (0.110 inches) to 3.43 mm (0.135 inches). The larger lumen diameter of the proximal region minimizes the overall flow resistance of the sheath. In one embodiment, the reduced diameter distal segment 630 has a length of approximately 2 cm to 4 cm. The relatively short length of the reduced diameter distal segment 630 allows the segment to be positioned in the common carotid artery CCA via a transcarotid approach, wherein the risk that the distal end of the sheath 605 will contact the bifurcation B is reduced.

[0089] In situations where the sheath inserted into the artery has a sharp sheath insertion angle and / or a short length, such as may be seen in a transcarotid access procedure, the distal tip of the sheath is more likely to be positioned partially or completely against the vessel wall, thereby limiting flow into the sheath. In one embodiment, the sheath is configured to center the tip in the vessel lumen. One such embodiment includes a balloon, such as the occluding element 129 described above. In another embodiment, the balloon may not occlude blood flow, but still center the tip of the sheath away from the vessel wall, like an inflatable buffer. In another embodiment, an expandable feature is located at the tip of the sheath and mechanically expands once the sheath is in place. Examples of mechanically expandable features include a braided structure or a helical structure or longitudinal struts that expand radially when shortened.

[0090] In one embodiment, occlusion of the vessel proximal to the distal tip of the sheath can be performed from outside the vessel, such as in a Rumel tourniquet or vessel ring proximal to the sheath insertion site. In alternative embodiments, an occluding device can be assembled around the sheath tip outside the vessel, such as an elastic ring, an inflatable cuff, or a mechanical clamp that can be tightened around the vessel and distal sheath tip. In a blood flow reversal system, this method of vessel occlusion minimizes the area of ​​static blood flow, thereby reducing the risk of thrombosis, and also ensures that the sheath tip is aligned with the vessel axis and is not partially or completely blocked by the vessel wall.

[0091] exist 9A to 9D Another arterial access device is shown in . This version has a different connection to the blood flow diverter than the previous version. Fig.9A Components of the arterial access device 110 are shown, including the arterial access sheath 605 , the sheath dilator 645 , the sheath stopper 705 , and the sheath guidewire 611 . Fig. 9B The arterial access device 110 is shown assembled for insertion into the carotid artery over a sheath guidewire 611. After the sheath is inserted into the artery and during surgery, the sheath guidewire 611 and sheath dilator 705 are removed. In this configuration, the sheath has a sheath body 605, a proximal extension 610, and a proximal hemostatic valve 625 having a flush line 635 and a stopcock 640. The proximal extension 610 extends from a Y-adapter 660 to the hemostatic valve 625, where the flush line 635 is connected. The sheath body 605 is the portion that is sized for insertion into the carotid artery and is actually inserted into the artery during use.

[0092] Instead of a Y-connector with a flow line connection terminating in a valve, the sheath has a Y-adapter 660 that connects the distal portion of the sheath to the proximal extension 610. The Y-adapter may also include a valve 670 that can be operated to open and close a fluid connection to a connector or hub 680 that can be removably connected to a flow line, such as a shunt. The valve 670 is located proximate to the lumen of the adapter 660, which communicates with the lumen of the sheath body 605. Fig. 9C and Fig.9D Details of the Y-adapter 660 with valve 670 and hub 680 are shown in cross section. Fig. 9C The valve is shown closed to the connector. This is the position the valve will be in during preparation of the arterial sheath. The valve is configured so that there is no possibility of trapped air during preparation of the sheath. Fig.9DThe valve to the connector opening is shown. Once the blood flow shunt 120 is connected to the hub 680, this position will be used and blood flow will be allowed from the arterial sheath to the shunt. This configuration eliminates the need to prepare both the flush line and the flow line, instead allowing preparation from a single flush line 635 and stopcock 640. This single point preparation is the same as the preparation of a conventional introducer sheath, which does not have a connection to the shunt line and is therefore more familiar and convenient for the user. In addition, the absence of a flow line on the sheath makes it easier to handle the arterial sheath during preparation and insertion into the artery.

[0093] Reference again Fig.9A , the sheath may also include a more distal second connector 690 that is separated from the Y-adapter 660 by a section of tubing 665. The purpose of this second connector and tubing 665 is to allow the valve 670 to be positioned more proximal to the distal tip of the sheath while still limiting the length of the insertable portion of the sheath 605, thereby allowing the user to reduce the level of exposure to radiation sources when the blood flow diverter is connected to the arterial sheath during surgery. In one embodiment, the distal connector 690 includes suture eyelets to help secure the sheath to the patient once positioned.

[0094] During transcarotid artery revascularization (TCAR) surgery, an arterial sheath 605 can be inserted into the patient's common carotid artery (CCA). As described elsewhere herein, in order to achieve reverse flow of blood, the CCA can be occluded to prevent antegrade blood flow from the aorta through the CCA. Blood flow through the CCA can be occluded with an external vascular ring or tape, a vascular clamp, an internal occluding member, such as a balloon or other type of closure device. When the blood flow through the CCA is blocked, the natural pressure gradient between the internal carotid artery (ICA) and the venous system will cause blood to flow retrogradely or reversely from the cerebral vascular system. Blood from the ICA and the external carotid artery (ECA) flows in a retrograde direction, and the system described herein allows retrograde blood to flow into the sheath 605, through the flow controller 1130, the venous sheath 910, and then backflow to the femoral vein of the patient, as described elsewhere herein. Loose embolic material can be brought into the arterial sheath 605 with the retrograde blood flow.

[0095] Venous return device

[0096] Reference now Fig. 10A and Fig. 10B , the venous return device 115 may include a distal sheath 910 and a flow line 915 that is connected to the shunt 120 and forms a leg thereof when the system is in use. The distal sheath 910 is adapted to be introduced into a venous return location, such as the jugular vein or femoral vein, through an incision or puncture. The distal sheath 910 and flow line 915 may be permanently attached or may be attached using a conventional Luer connector, such as Fig. 10A Optionally, Fig. 10BAs shown, the sheath 910 can be coupled to the flow line 915 by a Y-connector 1005. The Y-connector 1005 can include a hemostatic valve 1010. The venous return device also includes a venous sheath dilator 1015 and an introducer guide wire 611 to introduce the venous return device into the internal jugular vein or other veins. Like the arterial access dilator 645, the venous dilator 1015 includes a central guide wire lumen, so that the combination of the venous sheath and the dilator can be placed on the guide wire 611. Optionally, the venous sheath 910 can include a flushing line 1020 with a stopcock 1025 at its proximal or distal end.

[0097] exist Fig. 10C and Fig.11 An alternative configuration is shown in . Fig. 10C Components of the venous return device 115 are shown, including the venous return sheath 910 , the sheath dilator 1015 , and the sheath guidewire 611 . Fig.11 The venous return device 115 is shown assembled for insertion into a central vein over a sheath guidewire 611. Once the sheath is inserted into the vein, the dilator and guidewire are removed. The venous sheath may include a hemostatic valve 1010 and a flow line 915. A stopcock 1025 at the end of the flow line allows the venous sheath to be flushed through the flow line before use. This configuration allows the sheath to be prepared from a single point, just like a conventional introducer sheath. The connection to the blood flow diverter 120 is made with a connector 1030 on the stopcock 1025.

[0098] In order to reduce the flow resistance of the overall system, the artery enters the streamline 615 ( Fig. 6A ) and venous return line 915 and Y-connector 620 ( Fig. 6A ) and 1005 can each have a relatively large lumen inner diameter, typically in the range of 2.54 mm (0.100 inches) to 5.08 mm (0.200 inches), and a relatively short length, typically in the range of 10 cm to 20 cm. A lower system flow resistance is desirable because it allows flow to be maximized during the portion of the surgery where the risk of emboli is greatest. A lower system flow resistance also allows the use of a variable flow resistance to control blood flow in the system, as described in more detail below. The dimensions of the venous return sheath 910 can be generally the same as the dimensions of the arterial access sheath 60S described above. In the venous return sheath, an extension for the hemostatic valve 1010 is not required.

[0099] Retrograde shunt

[0100] The shunt 120 may be comprised of a single tube or multiple connected tubes that provide fluid communication between the arterial access conduit 110 and the venous return conduit 115 to provide a path for retrograde blood flow therebetween. Figure 1AAs shown, shunt 120 is connected to flow line 615 of arterial access device 110 at one end (via connector 127a) and to flow line 915 of venous return catheter 115 at an opposite end (via connector 127b).

[0101] In one embodiment, the shunt 120 may be formed by at least one tube in communication with the flow control assembly 125. The shunt 120 may be any structure that provides a fluid path for blood flow. The shunt 120 may have a single lumen or it may have multiple lumens. The shunt 120 may be removably attached to the flow control assembly 125, the arterial access device 110, and / or the venous return device 115. Before use, the user may select a shunt 120 of a length that is most suitable for use with the arterial access location and the venous return location. In one embodiment, the shunt 120 may include one or more extension tubes that can be used to change the length of the shunt 120. The extension tubes may be modularly attached to the shunt 120 to achieve the desired length. The modular aspect of the shunt 120 allows the user to extend the shunt 120 as needed, depending on the location of the venous return. For example, in some patients, the internal jugular vein IJV is small and / or tortuous. Due to the proximity to other anatomical structures, the risk of complications at this location may be higher than the risk at some other locations. In addition, a neck hematoma may cause airway obstruction and / or cerebrovascular complications. Therefore, for such patients, it may be necessary to locate a venous return site in a location other than the internal jugular vein IJV, such as the femoral vein. The femoral return site can be achieved percutaneously with a low risk of serious complications, and it also provides alternative venous access to the central veins if the internal jugular vein IJV is not available. In addition, the femoral return changes the layout of the reverse flow shunt so that the shunt controls can be located closer to the interventional "working area" where the device is introduced and the contrast injection port is located.

[0102] In one embodiment, the shunt 120 has an inner diameter of 4.76 mm (3 / 16 inch) and a length of 40-70 cm. As mentioned, the length of the shunt can be adjusted. In one embodiment, the connector between the shunt and the arterial and / or venous access device is configured to minimize flow resistance. In one embodiment, the arterial access sheath 110, the retrograde shunt 120, and the venous return sheath 115 are combined to create a low flow resistance arteriovenous AV shunt, such as Figures 1A to 1D As described above, the connections and flow lines of all of these devices are optimized to minimize or reduce flow resistance. In one embodiment, the AV shunt has a flow resistance that enables flow rates up to 300 mL / min when there are no devices in the arterial sheath 110 and when the AV shunt is connected to a fluid source with blood viscosity and a static head of 60 mmHg. The actual shunt resistance may depend on the presence of a check valve 1115 or a filter 1145 (e.g., Fig.12The length of the flow divider (as shown) or flow transmitter may vary and flow rates between 150 and 300 mL / min may be achieved.

[0103] When a device, such as a stent delivery catheter, is placed in the arterial sheath, the flow resistance of a section of the arterial sheath increases, which in turn increases the flow resistance of the entire AV shunt. This increase in flow resistance will correspondingly reduce the flow rate. In one embodiment, Fig. 6A The Y-arm 620 shown connects the arterial sheath body 605 to a flow line 615 at a distance from the hemostatic valve 625, where the catheter is introduced into the sheath. This distance is set by the length of the proximal extension 610. Therefore, the section of the arterial sheath that is restricted by the catheter is limited to the length of the sheath body 605. The actual blood flow restriction will depend on the length and inner diameter of the sheath body 605, and the outer diameter of the catheter. As described above, the sheath length can range from 5 to 15 cm, typically 10 cm to 12 cm, and the inner diameter is typically in the range of 7 Fr (1 Fr = 0.33 mm) to 10 Fr, typically 8 Fr. The stent delivery catheter can range from 3.7 Fr. to 5.0 or 6.0 Fr, depending on the size of the stent and the manufacturer. This restriction can be further reduced if the sheath body is designed to increase the inner diameter of the portion that is not in the blood vessel (stepped sheath body), such as Figure 6B Since blood flow restriction is proportional to the fourth power of the lumen distance, a small increase in lumen or annular area results in a large decrease in flow resistance.

[0104] The actual flow through the AV shunt when in use will further depend on the patient's cerebral blood pressure and flow resistance.

[0105] Flow Control Components - Regulation and Monitoring of Retrograde Blood Flow

[0106] The flow control assembly 125 interacts with the retrograde shunt 120 to regulate and / or monitor the retrograde flow rate from the common carotid artery to a venous return site, such as the femoral vein, the internal jugular vein, or to an external container 130. In this regard, the flow control assembly 125 enables the user to achieve a higher maximum flow rate than existing systems, and also selectively adjust, set, or otherwise regulate the retrograde flow rate. Various mechanisms can be used to regulate the retrograde flow rate. The flow control assembly 125 enables the user to configure the retrograde blood flow in a manner suitable for various treatment regimens, as described below.

[0107] Fig.12An example of a system 100 is shown with a schematic diagram of a flow control assembly 125 positioned along a shunt 120 such that retrograde blood flow passes through at least a portion of the flow control assembly 125 or is otherwise in communication therewith. The flow control assembly 125 may include various controllable mechanisms for regulating and / or monitoring retrograde blood flow. The mechanisms may include various devices for controlling retrograde blood flow, including one or more pumps 1110, valves 1115, syringes 1120, and / or variable resistance components 1125. The flow control assembly 125 may be manually controlled by a user and / or automatically controlled via a controller 1130 to change the flow through the shunt 120. For example, by changing the flow resistance, the rate of retrograde blood flow through the shunt 120 may be controlled. The controller 1130, which will be described in more detail below, may be integrated into the flow control assembly 125, or it may be a separate component that is in communication with components of the flow control assembly 125.

[0108] In addition, the flow control assembly 125 may include one or more flow sensors 1135 and / or anatomical data sensors 1140 (described in detail below) for sensing one or more aspects of retrograde blood flow. A filter 1145 may be positioned along the shunt 120 to remove emboli before blood flows back to the venous return site. When the filter 1145 is positioned upstream of the controller 1130, the filter 1145 may prevent emboli from entering the controller 1145 and potentially clogging the variable flow resistance component 1125. It should be understood that the various components of the flow control assembly 125 (including the pump 1110, valve 1115, syringe 1120, variable resistance component 1125, sensors 1135 / 1140 and filter 1145) may be positioned at various locations along the shunt 120 and at various upstream or downstream locations relative to each other. The components of the flow control assembly 125 are not limited to Fig.12 . In addition, flow control assembly 125 need not include all of the components, but may include various sub-combinations of components. For example, a syringe may optionally be used within flow control assembly 125 to regulate flow, or it may be used external to the assembly for purposes other than flow regulation, such as to introduce a fluid, such as a radiopaque contrast agent, into an artery in an antegrade direction via shunt 120.

[0109] Both the variable resistance component 1125 and the pump 1110 can be connected to the shunt 120 to control the retrograde flow rate. The variable resistance component 1125 controls the flow resistance, while the pump 1110 provides a positive displacement of blood through the shunt 120. Therefore, the pump can be activated to drive retrograde blood flow, rather than relying on the perfusion stump pressure and venous back pressure of the ECA and ICA to drive retrograde blood flow. The pump 1110 can be a peristaltic tube pump or any type of pump, including a positive displacement pump. The pump 1110 can be activated and deactivated (manually or automatically via the controller 1130) to selectively achieve blood displacement through the shunt 120 and control the flow rate through the shunt 120. The blood displacement through the shunt 120 can also be achieved in other ways, including using a suction syringe 1120, or a suction source can be used, such as a vacuum blood collection tube, a vacuum lock syringe or a wall suction. The pump 1110 can communicate with the controller 1130.

[0110] One or more flow control valves 1115 may be positioned along the path of the shunt. The valves may be manually actuated or automatically actuated (via controller 1130). Flow control valve 1115 may be, for example, a one-way valve, a check valve, or a high-pressure valve that prevents blood flow in the shunt 120 in the antegrade direction, which will close the shunt 120, for example, during high-pressure contrast injection (which is intended to enter the arterial vascular system in the antegrade direction). In one embodiment, the one-way valve is a low-resistance valve, such as the low-resistance valve described in U.S. Pat. No. 5,727,594 or other low-resistance valves.

[0111] In one embodiment of a flow divider having a filter 1145 and a one-way check valve 1115, the check valve is located downstream of the filter. In this way, if there is debris traveling in the flow divider, it will be trapped in the filter before reaching the check valve. Many check valve configurations include a sealing member that seals against a housing containing a flow chamber. Debris may be trapped between the sealing member and the housing, thereby affecting the ability of the valve to seal against reverse pressure.

[0112] The controller 1130 communicates with the components of the system 100, including the flow control assembly 125 to enable manual and / or automatic regulation and / or monitoring of retrograde blood flow through the components of the system 100 (including, for example, the shunt 120, the arterial access device 110, the venous return device 115, and the flow control assembly 125). For example, a user may actuate one or more actuators on the controller 1130 to manually control the components of the flow control assembly 125. The manual controls may include switches or dials or similar components located directly on the controller 1130, or components remote from the controller 1130, such as a foot pedal or similar device. The controller 1130 may also automatically control the components of the system 100 without input from the user. In one embodiment, the user may program the software in the controller 1130 to enable such automatic control. The controller 1130 may control the actuation of the mechanical portions of the flow control assembly 125. Controller 1130 may include circuitry or programming that interprets signals generated by sensors 1135 / 1140 such that controller 1130 may control actuation of flow control assembly 125 in response to such signals generated by the sensors.

[0113] Fig.12 The representation of the controller 1130 in FIG. 1 is merely exemplary. It should be understood that the appearance and structure of the controller 1130 may vary. Fig.12 1130 is shown as being integrated into a single housing. This allows a user to control the flow control assembly 125 from a single location. It should be understood that any of the components of the controller 1130 may be separated into separate housings. In addition, Fig.12 The controller 1130 and the flow control assembly 125 are shown as separate housings. It should be understood that the controller 1130 and the flow control regulator 125 can be integrated into a single housing, or can be separated into multiple housings or components.

[0114] Blood flow status indicator

[0115] The controller 1130 may include one or more indicators that provide the user with visual and / or audio signals about the state of retrograde blood flow. The audio indication advantageously reminds the user of the blood flow state without the user visually checking the flow controller 1130. The indicator may include a speaker 1150 and / or a light 1155 or any other device for conveying the state of retrograde blood flow to the user. The controller 1130 may communicate with one or more sensors of the system to control the activation of the indicator. Alternatively, the activation of the indicator may be directly bound to the user who actuates one of the flow control actuators 1165. The indicator light does not have to be a speaker or a light. The indicator may be just a button or a switch that visually indicates the state of retrograde blood flow. For example, a button in a certain state (such as a pressed or down state) may be a visual indication that the retrograde blood flow is in a high state. Alternatively, a switch or dial pointing to a blood flow state of a specific mark may be a visual indication that the retrograde blood flow is in a marked state.

[0116] Flow rate actuator

[0117] The controller 1130 may include one or more actuators that a user may press, switch, manipulate, or otherwise actuate to adjust the retrograde flow rate and / or monitor the flow rate. For example, the controller 1130 may include a flow control actuator 1165 (such as, one or more buttons, knobs, dials, switches, etc.) that a user may actuate to cause the controller to selectively change an aspect of the reverse blood flow. For example, in the illustrated embodiment, the flow control actuator 1165 is a knob that can be turned to various discrete positions, each of which corresponds to the controller 1130 that enables the system 100 to achieve a specific retrograde flow rate. States include, for example, (a) off; (b) low flow; (c) high flow; (d) suction. It should be understood that the above states are merely exemplary and that different states and combinations of states may be used. The controller 1130 achieves various retrograde blood flow states by interacting with one or more components of the system, including sensors, valves, variable resistance components, and / or pumps. It should be appreciated that the controller 1130 may also include circuitry and software to adjust the retrograde flow rate and / or monitor the flow rate such that the user need not actively actuate the controller 1130 .

[0118] The closed state corresponds to a state in which there is no retrograde blood flow through the shunt 120. When the user sets the flow control actuator 1165 to closed, the controller 1130 stops the retrograde blood flow, such as by closing a valve or closing a stopcock in the shunt 120. The low flow and high flow states correspond to low retrograde flow rates and high retrograde flow rates, respectively. When the user sets the flow control actuator 1165 to low flow or high flow, the controller 1130 interacts with components of the flow control regulator 125, including the pump 1110, valve 1115 and / or variable resistance component 1125, to increase or decrease the flow rate accordingly. Finally, the aspiration state corresponds to opening a circuit to a suction source, such as a vacuum blood collection tube or a suction unit (if active retrograde blood flow is required).

[0119] The system can be used to change blood flow between various states, including an active state, a passive state, a suction state, and a closed state. The active state corresponds to the system using a device that actively drives retrograde blood flow. For example, such an active device may include, for example, a pump, a syringe, a vacuum source, etc. The passive state corresponds to when the retrograde blood flow is driven by the perfusion stump pressure of the ECA and ICA and possibly by venous pressure. The suction state corresponds to the system using a suction source, for example, a vacuum blood collection tube or a suction unit to drive the retrograde blood flow. The closed state corresponds to the system having zero retrograde blood flow, such as the result of closing a stopcock or valve. Low flow rate and high flow rate can be passive or active blood flow states. In one embodiment, specific values ​​of low flow rate and / or high flow rate (for example, in ml / minute) can be predetermined and / or pre-programmed into the controller so that the user does not actually need to set or enter the value. Instead, the user simply selects "high flow" and / or "low flow" (such as by pressing an actuator, such as a button on the controller 1130), and the controller 1130 interacts with one or more components of the flow control assembly 125 to cause the flow rate to achieve a predetermined high or low flow rate value. In another embodiment, the user sets or enters a value for the low flow rate and / or high flow rate, such as set or entered into the controller. In another embodiment, the low flow rate and / or high flow rate are not actually set. Instead, external data (such as data from the anatomical data sensor 1140) is used as a basis for affecting the flow rate.

[0120] The flow control actuator 1165 can be a plurality of actuators, such as one actuator for switching the state from low flow to high flow, such as a button or switch, and another actuator for closing the flow loop to close, for example, during contrast injection when directing the contrast agent antegrade to the carotid artery. In one embodiment, the flow control actuator 1165 may include a plurality of actuators. For example, one actuator may be operated to switch the flow rate from low to high, another actuator may be operated to temporarily stop the blood flow, and a third actuator (such as a stopcock) may be operated to aspirate using a syringe. In another example, one actuator is operated to switch to low flow, and another actuator is operated to switch to high flow. Alternatively, the flow control actuator 1165 may include a plurality of actuators for switching the state from low flow to high flow, and additional actuators for fine-tuning the flow rate within the high flow state and the low flow state. When switching between low flow and high flow, these additional actuators may be used to fine-tune the flow rate in those states. Therefore, it should be understood that within each state (ie, high flow state and low flow state), various flow rates can be dialed in and fine-tuned. A wide variety of actuators can be used to achieve control of blood flow states.

[0121] The controller 1130 or various components of the controller 1130 may be located at various positions relative to the patient and / or relative to other components of the system 100. For example, the flow control actuator 1165 may be located near a hemostasis valve where any interventional tools are introduced into the patient so that the flow control actuator 1165 is accessible during the introduction of the tools. The location may vary, for example, based on whether a transfemoral or transcarotid approach is used, such as Figures 1A to 1C As shown. The controller 1130 may have a wireless connection to the rest of the system 100 and / or a wired connection of adjustable length to allow remote control of the system 100. The controller 1130 may have a wireless connection and / or a wired connection of adjustable length to the flow control regulator 125 to allow remote control of the flow control regulator 125. The controller 1130 may also be integrated into the flow control regulator 125. When the controller 1130 is mechanically connected to the components of the flow control assembly 125, a tether with mechanical actuation capability may connect the controller 1130 to one or more of the components. In one embodiment, the controller 1130 may be positioned at a sufficient distance from the system 100 to allow the controller 1130 to be positioned outside of the radiation field when fluoroscopy is used.

[0122] Any of the controller 1130 and its components can interact with other components of the system (such as pumps, sensors, shunts, etc.) in various ways. For example, any of a variety of mechanical connections can be used to achieve communication between the controller 1130 and the system components. Alternatively, the controller 1130 can communicate electronically or magnetically with the system components. Electromechanical connections can also be used. The controller 1130 can be equipped with control software that enables the controller to implement control functions with system components. The controller itself can be a mechanical, electrical or electromechanical device. The controller can be mechanically, pneumatically or hydraulically actuated or electromechanically actuated (for example, in the case of solenoid actuation of a flow control state). The controller 1130 may include a computer, a computer processor and a memory, as well as data storage capabilities.

[0123] Fig.13 An exemplary embodiment of a variable flow control element 1125 is shown. In this embodiment, the flow resistance through the flow divider 120 can be varied by providing two or more alternative flow paths to create low resistance and high resistance flow paths. Fig.13 As shown, blood flow through the shunt 120 passes through the main cavity 1700 and the secondary cavity 1705. The secondary cavity 1705 is longer and / or has a smaller diameter than the main cavity 1700. Therefore, the secondary cavity 1705 has a higher flow resistance than the main cavity 1700. By passing the blood through both cavities, the flow resistance will be minimized. Due to the pressure drop created in the main cavity 1700 across the inlet and outlet of the secondary cavity 1705, the blood can flow through both cavities 1700 and 1705. This has the benefit of preventing blood stasis. As shown in FIG. Fig.14 As shown, by blocking the blood flow through the main chamber 1700 of the shunt 120, the blood flow is completely diverted to the secondary chamber 1705, thereby increasing the flow resistance and reducing the blood flow rate. It should be understood that additional flow chambers can also be provided in parallel to allow three, four or more discrete flow resistances. The shunt 120 can be equipped with a valve 1710, which controls the blood flow to the main chamber 1700 and the secondary chamber 1705. The position of the valve can be controlled by an actuator, such as a button or switch on the housing of the flow controller 125. Fig.13 and Fig.14 Embodiments of the invention have the advantage that they maintain precise lumen size even at the lowest flow settings. The size of the secondary lumen can be configured to prevent thrombosis even at the lowest flow or prolonged blood flow conditions. In one embodiment, the lumen diameter of the secondary lumen 1705 is 0.063 inches or greater.

[0124] In one embodiment, the connectors connecting the components of the reverse blood flow system are large-bore, quick-connect connectors. Fig. 9BAs shown, the male large bore hub 680 on the Y-adapter 660 of the arterial sheath 110 is connected to the female counterpart 1320 on the arterial side of the blood flow shunt 120. Similarly, the male large bore connector 1310 on the venous side of the blood flow shunt 120 is connected to the female counterpart connector 1310 on the flow line of the venous sheath 115, as shown. Fig. 10C Connections can be standard female and male Luer connectors or other styles of tubing connectors.

[0125] sensor

[0126] As mentioned, the flow control assembly 125 may include or interact with one or more sensors that communicate with the system 100 and / or communicate with the patient's anatomical structure. Each of the sensors may be adapted to respond to a physical stimulus (including, for example, heat, light, sound, pressure, magnetism, motion, etc.) and transmit a resulting signal for measurement or display or to operate the controller 1130. In one embodiment, the flow sensor 1135 interacts with the shunt 120 to sense an aspect of the blood flow through the shunt 120, such as the flow rate or volume rate of the blood flow. The flow sensor 1135 may be directly coupled to a display that directly displays the value of the volume flow rate or flow rate. Alternatively, the flow sensor 1135 may feed data to the controller 1130 to display the volume flow rate or flow rate.

[0127] The type of flow sensor 1135 can vary. The flow sensor 1135 can be a mechanical device, such as a paddle wheel, a flapper valve, a rolling ball, or any mechanical component that responds to the flow of blood through the shunt 120. The movement of the mechanical device in response to the flow of blood through the shunt 120 can be used as a visual indication of fluid flow, and can also be calibrated to a scale as a visual indication of the fluid flow rate. The mechanical device can be coupled to an electrical component. For example, a paddle wheel can be positioned in the shunt 120 so that the fluid flow causes the paddle wheel to rotate, wherein a greater fluid flow rate causes a greater rotational speed of the paddle wheel. The paddle wheel can be magnetically coupled to a Hall effect sensor to detect the rotational speed, which indicates the fluid flow rate through the shunt 120.

[0128] The system 100 is not limited to the use of a flow sensor 1135 positioned in the shunt 120, or a sensor that interacts with the venous return device 115 or the arterial access device 110. For example, the anatomical data sensor 1140 may communicate or otherwise interact with an anatomical structure of the patient, such as a neuroanatomical structure of the patient. In this manner, the anatomical data sensor 1140 may sense measurable anatomical aspects directly or indirectly related to the retrograde flow rate from the carotid artery. For example, the anatomical data sensor 1140 may measure blood flow conditions in the brain, such as the flow rate in the middle cerebral artery, and communicate these conditions to the display and / or controller 1130 to adjust the retrograde flow rate based on predetermined criteria. In one embodiment, the anatomical data sensor 1140 includes a transcranial Doppler ultrasound examination (TCD), which is an ultrasound test that uses reflected sound waves to evaluate blood as it flows through the brain. Using TCD generates a TCD signal that can be communicated to the controller 1130 to control the retrograde flow rate to achieve or maintain a desired TCD profile. The anatomical data sensor 1140 may be based on any physiological measurement, including reverse flow velocity, blood flow through the middle cerebral artery, TCD signals of embolic particles, or other neuromonitoring signals.

[0129] In another safety mechanism, the controller 1130 includes a timer 1170 ( Fig.12 ), which is timed relative to the time the flow rate is at a high flow rate. The controller 1130 can be programmed to automatically return the system 100 to a low flow rate after a predetermined high flow rate period, for example, after 15, 30, or 60 seconds or more of high flow rate. After the controller returns to a low flow rate, the user can initiate another predetermined high flow rate period as desired. In addition, the user can override the controller 1130 to cause the system 100 to move to a low flow rate (or high flow rate) as desired.

[0130] Example Percutaneous Sheath Embodiments

[0131] Fig.15AA schematic diagram of an embodiment of a sheath 1505 configured to percutaneously access and occlude a blood vessel, such as an artery (e.g., a common carotid artery) is shown. The sheath 1505 (or any of the sheaths described herein) can be configured according to or in addition to the arterial access device 110 described above. The sheath 1505 has an inner lumen and a distal tip 1502. The sheath 1505 has a distal region 1510 that includes an expandable portion 1515 that is configured to expand radially outward and occlude or partially occlude the blood vessel when positioned in the blood vessel. The expandable portion 1515 includes a plurality of corrugations or other similar structures (such as an accordion-like structure or a corrugated body that expands and contracts along its length) that can be switched between a contracted state and an expanded state, wherein the expanded state is suitable for occluding (or partially occluding) the blood vessel. In one embodiment, the expandable portion 1515 is a braid or mesh (such as nitinol) with a coating positioned on or above the braid or mesh, such as a polymer coating or fabric (such as a polymer coated fabric). In any of the embodiments described herein, the sheath may have an angled shape, such as one or more bends or curves, so that the distal tip is centered in the blood vessel. Such a bend may be sharp or pointed relative to the long axis of the sheath, or the bend may have a soft bend. Such a bend may be positioned at the distal tip of the expandable element, such as the distal end of the balloon, within the balloon or proximal to the balloon.

[0132] The expandable portion 1515 can be connected to an elongated actuator element, such as one or more tension wires, which travel through a small or appropriately sized lumen in the wall of the sheath 1505 to the proximal end of the sheath 1505. The actuator element is connected to a control element, such as a tension ring 1525 on a proximal hub 1525 of the sheath 1505. The proximal hub 1525 can include a flushing port 1517.

[0133] By applying or removing tension (or compression) on the expandable portion 1515 via the actuator element 1520 and the tension ring 1525, the expandable portion 1515 can be in a contracted state ( Fig. 15B ) and expansion state ( Fig. 15C ). When force (tension or compression) is applied, the expandable portion 1515 radially expands into an enlarged disc shape that, when positioned in a vessel, occludes the vessel. When the force is released, the expandable portion 1515 relaxes and flattens again, allowing the sheath to be removed from the vessel. Depending on the mechanism, an increase or reduction in applied force can be used to occlude a vessel or remove an occlusion.

[0134] Force (tension or compression) may be applied to the expandable portion 1515 by actuating the tension ring 1525, such as via a screw or pulley system. It should be understood that other mechanisms for creating and reducing tension may also be used, such as, for example, a stretching and locking system to advance / retract the braid / mesh into / from the polymer material, or other devices known in the art.

[0135] Fig.16A A schematic diagram of the distal region of a sheath 1605 embodiment configured for percutaneous access and occlusion of a blood vessel is shown. The embodiment includes one or more wings or flaps 1610 positioned on the distal region of the sheath 1605. The flap 1610 is attached to the outer region of the sheath 1605 at a base region 1612. One or more expandable members 1615 (such as a balloon) are positioned at or near the base region 1612 between the inner surface of the flap and the outer surface of the sheath. In the collapsed state, the flap 1610 is positioned flush or substantially flush with the outer surface of the sheath 1605 so that the flap 1610 does not contribute or makes minimal contribution to the diameter of the sheath 1605.

[0136] The flap 1610 can be switched to an expanded state ( Fig. 16B ), wherein flap 1610 protrudes outwardly from sheath 1605 like a cantilever. This is caused by the expandable member 1615 switching to a larger size and pushing flap 1610 to the expanded state. The expandable member 1615 can be switched to a larger size, such as by being inflated through one or more inflation lumens in the sheath 1605. To switch back to the contracted state, the expandable member 1615 is scaled so that its size is reduced. The flap is grasped downward to allow the sheath to be pulled out of the blood vessel. Flap 1610 can be used in combination with any of the expandable elements described herein, such as an expandable balloon.

[0137] The flaps may be made of any of a variety of materials, such as polymeric materials, polymer-coated fabrics, or other non-porous materials that prevent blood from passing and occluding the vessel. The flaps may overlap each other around the circumference of the sheath to achieve complete circumferential occlusion of the vessel.

[0138] Fig.17A A schematic diagram of the distal region of an embodiment of a sheath 1705 configured for percutaneous access and occlusion of a blood vessel is shown. The embodiment includes an expandable umbrella element 1710 (shown in phantom) at the distal region, wherein the umbrella element extends in an annular manner around the entire circumference of the sheath. The umbrella element 1710 is Fig.17A The contracted state and Fig. 17BThe umbrella can be made of various materials, such as nitinol or stainless steel (frame) or polymer, polymer-coated fabric or other non-porous material (covering). The umbrella element 1710 includes or is attached to one or more tethers 1715 (such as wires, rods, etc.) extending from the umbrella element 1710 to the proximal hub of the sheath 1705, wherein the user can actuate the tethers 1715 to control the expansion and contraction of the umbrella element 1710. The tethers 1715 are actuated via pushing, twisting, tightening or other mechanisms at the proximal hub to move the umbrella element between the expanded and contracted states. When the wire is pushed in the distal direction, it applies a force that causes the umbrella element to open (i.e., expand) and occlude the blood vessel. The tethers can have sufficient column strength to allow the user to push the tethers so that they apply force to the umbrella element.

[0139] exist Fig.17A and Fig. 17B In the embodiment of the present invention, the umbrella-shaped element is located on the outer surface of the sheath tube 1705. Fig.17A In the retracted, collapsed or unexpanded state shown, the umbrella element is positioned to be flat or substantially flush with the outer surface of the sheath so that the umbrella element does not substantially increase the outer dimensions of the sheath. Fig.17A and Fig. 17B The tether 1715 is pushed leftward to apply force to the umbrella element. As the tether 1715 is advanced, the distal-most tip of the umbrella element remains fixed to the sheath, while the proximal region of the umbrella element moves in the distal direction. This causes the umbrella element 1710 to open radially outward into a conical, biconical, or other expanded shape. The tether can be retracted rearward to close the umbrella element.

[0140] Fig.18A Another embodiment of an umbrella-shaped element 1810 on a sheath 1805 is shown. In this embodiment, the umbrella-shaped element 1810 is positioned between an outer sheath layer 1815 and a coaxial inner sheath layer 1820, such as Fig.18B . The umbrella element 1810 is attached to one or more tethers 1830, which can be advanced to slide the umbrella outwardly and distally from between the outer sheath layer 1815 and the coaxial inner sheath layer 1820. The umbrella element expands outward to an expanded state. The umbrella element 1810 can be made of a shape memory wire, such as nitinol, which expands radially outward when the umbrella element is withdrawn from the sheath. The tethers 1830 can be retracted to slide the umbrella back between the outer sheath layer 1815 and the coaxial inner sheath layer 1820 or to reinsert the umbrella between the outer sheath layer 1815 and the coaxial inner sheath layer 1820, thereby contracting.

[0141] Fig.19A and Fig.19BAnother embodiment of an umbrella element 1910 is shown on a sheath 1905. In this embodiment, the umbrella element is formed by a frame 1920 coupled to a push wire (or similar, rod) 1930 extending toward the proximal hub. The metal frame 1920 and push wire 1930 are slidably positioned between the inner and outer sheath layers.

[0142] The umbrella element 1910 can be made of a deformable material, such as a fabric or a polymer, and is positioned outside of the sheath 1905. The umbrella element 1910 includes a slotted track 1935. When the frame 1920 is pushed distally (via the push wire 1930), the arms of the frame 1920 are pushed out and slide along the slotted track 1935. This causes the umbrella element to expand, such as Fig.19B shown.

[0143] Fig. 20A and Fig. 20B The distal region of the sheath 2005 is shown. An expandable element, such as a balloon 2010, is coupled to the distal region of the sheath 2005. The balloon 2010 is Fig. 20A and Fig. 20B 2005 is shown in an expanded state such that the balloon 2010 flares outwardly from the outer wall or distal edge of the sheath 2005 in a manner that allows the balloon 2010 to at least partially occlude the blood vessel. The sheath 2005 can be formed such that the inner and outer walls form an annular cavity that accommodates the balloon 2010 in a constrained or non-expanded state. Alternatively, the balloon 2010 can be constrained within the lumen of the sheath 2005 when constrained. In this manner, the sheath 2005 can provide protection for the balloon 2010, such as during insertion of the sheath 2005 into a blood vessel.

[0144] The configuration of the balloon 2010 can vary. For example, in one embodiment, the balloon 2010 is formed solely of a compliant or malleable material that is configured to expand into a desired shape when inflated (such as via an inflation lumen in the sheath 2005).

[0145] In another embodiment, the balloon includes or is coupled to one or more actuating elements 2015 that can be actuated to convert the balloon to an expanded shape. For example, the actuating element can be a line attached to or molded within the balloon. The line can be used to push the balloon 2010 out of the distal region of the sheath 2005, where the balloon can be inflated to an expanded state. The line can include, for example, a shape memory material (such as Nitinol) that provides support for the desired shape of the balloon 2010 in the expanded state. The balloon can be scaled and pulled back into the sheath using the line to convert the balloon 2010 to a constrained state, such as during the withdrawal of the sheath 2005 from a blood vessel.

[0146] In another embodiment, the balloon 2010 is molded around one or more shape memory wires that cause the balloon to flare outwardly to the vessel wall when the balloon is expanded. When the balloon is deflated, vacuum pressure directs the wires back into the sheath.

[0147] Fig.21A and Fig.21B Another embodiment of a distal region of a sheath 2105 is shown that includes an expandable balloon 2110 formed by a compliant ring integrated into the outer wall of the sheath 2005. The balloon 2110 is a deformable, annular structure that extends circumferentially around the outer wall of the sheath. The balloon 2005 includes one or more inflation chambers that can be used to expand the balloon from a constrained or smaller shape ( Fig.21A ) to an expanded shape ( Fig.21B ). The inflation lumen may be coaxial or non-coaxial with the sheath. In one method of manufacture, the balloon is attached to the sheath 2005 using a laser bonding process. The laser is used to heat the material of the balloon so that the balloon fuses or bonds with the distal region of the sheath. The balloon may be formed of a flexible, compliant material, and the sheath is made of a polymer in an embodiment.

[0148] FIG. 22A to FIG. 22C Another embodiment of a distal region of a sheath 2205 is shown that includes an expandable balloon 2210 integrated into the outer wall of the sheath 2205. For example, the balloon 2210 can be located on the outer wall, or it can be at least partially located within the outer wall, such as between the inner and outer layers of the outer wall of the sheath. The expandable balloon 2210 is coupled to the outer wall so that when the balloon 2210 is in a position such as Fig.22A In the deflated or unexpanded state shown, the balloon 2210 does not increase the diameter of the sheath. The balloon 2210 is made of a compliant material that can stretch along the long axis of the sheath 2205, such as Fig.22A , which shows a balloon 2210 in a stretched state (stretched along the length of the sheath). This stretched configuration eliminates or reduces wrinkles or undulations in the balloon. The stretched configuration also places the balloon in tension 2210 so that the outer diameter of the balloon 2210 (and the sheath 2205) is reduced or minimized, such as during insertion of the sheath 2205 into a blood vessel.

[0149] refer to Fig. 22B , the tension in the balloon 2210 can be relaxed or otherwise released so that the length of the balloon 2210 along the longitudinal axis of the sheath 2205 is relatively Fig.22A The stretched configuration shown is reduced. With the balloon 2210 no longer under tension, the material of the balloon 2210 now has the ability to expand radially outward. The balloon 2210 can then be inflated (e.g., via one or more inflation lumens in the sheath 2205) to transition the balloon 2210 to an expanded state with an increased outer diameter, such as Fig. 22Cas shown in .

[0150] Fig.22A The stretched configuration of the balloon 2210 shown in the figure can be achieved in various ways. For example, by pulling back proximally on the outer portion of the sheath 2205 (as shown by arrow 2215), so that it pulls and stretches the attached portion of the balloon 2210. The outer portion of the sheath 2205 can then be locked in place with a locking element located at the proximal hub of the sheath 2205, such as a latch, screw, lock, hook, etc.

[0151] Non-limiting examples of mechanisms that may be coupled to the sheath 2205 to control the tensioned configuration of the balloon 2210 are now described. Fig.23A A first mechanism 2305 is shown coupled or otherwise connected to a proximal hub 2302 of a sheath 2205, comprising an inner shaft 2310 and a coaxial outer shaft 2315 slidable relative to the inner shaft 2310. The hub 2302 comprises a first component 2320 attached to the outer shaft 2315 and a second component 2325 attached to the inner shaft 2310. A sealing element 2330, such as an O-ring, provides a sealing relationship between the first component 2320 and the second component 2325. The balloon is attached to the outer shaft 2315 at a proximal end and to the inner shaft 2310 at a distal end, such that relative movement between the inner shaft 2310 and the outer shaft 2315 can be used to place the balloon 2210 in a stretched configuration. The hub 2302 also comprises an inflation path 2335, which can be used to inflate the balloon 2210.

[0152] Fig. 23B A perspective view of the second component 2325 is shown. The second component 2325 has an elongated body 2340 that is slidably positioned in a cavity 2345 ( Fig.23A ) so that the second component 2325 can slide relative to the first component along the long axis of the sheath tube 2205, such as Fig.23A As shown by arrow A in the reference Fig. 23B The body 2340 of the second component 2325 has a translation path 2350 in which the pin 2355 of the first component 2320 is positioned. The translation path 2350 and the pin 2355 engage one another so that they together define a slidable movement between the first component 2320 and the second component 2325.

[0153] Prior to inflation of the balloon 2210, the hub 2302 is actuated by displacing the first member 2322 relative to the second member 2325. This results in relative movement between the inner shaft 2310 (which is attached to the balloon 2210) and the outer shaft 2315 (which is also attached to the balloon 2210), allowing the user to selectively place the balloon 2210 in a tensioned configuration (e.g., Fig.22A as shown) or in a non-tensioned form (as Fig. 22BWhen in the untensioned configuration, balloon 2210 can be inflated via inflation path 2335.

[0154] Fig.24A and Fig. 24B (which is not drawn to scale) shows an alternative mechanism that can be coupled to the sheath 2205 for controlling the tensioned configuration of the balloon. Fig.24A The balloon 2210 is shown in a deflated state, and Fig. 24B The balloon 2210 is shown in an expanded state. The hub 2405 is located at the proximal region of the sheath 2205 and includes an access device, such as a Luer element 2415 that provides access to the lumen of the sheath 2205. The hub 2405 includes a first hub portion 2420 attached to the inner shaft 2310 and a second hub portion 2425 attached to the outer shaft 2315 of the sheath 2205. The inner shaft 2310 is attached to the distal end of the balloon 2210. The outer shaft 2315 is attached to the proximal end of the balloon 2210.

[0155] The second hub portion 2425 is slidably positioned within the interior cavity of the first hub portion 2420. The second hub portion 2425 is movable within the cavity along the long axis of the sheath 2205. The second hub portion 2425 divides the interior cavity into a proximal portion 2435 and a distal portion 2440. A biasing element, such as a spring 2440, is positioned in the second hub portion 2440 to bias the second hub portion 2425 toward the proximal portion 2435 of the interior cavity. The seal is positioned to provide a sealed separation between the proximal portion 2435 and the distal portion 2440. In addition, an inflation shaft 2450 is in communication with the proximal portion 2435 and the balloon 2210.

[0156] The spring 2440 maintains a constant tension on the outer shaft 2315 via the second hub portion 2425, so that the balloon 2210 is maintained in a default contracted state, such as Fig.24A In this state, the balloon 2210 is stretched along its length. The balloon 2210 can be inflated via the inflation shaft 2450, which causes the balloon 2210 to expand outward and thus retract the outer shaft 2315 proximally, as shown. Fig. 24B As shown. Inflation of the balloon via inflation shaft 2450 also increases the pressure of cavity 2435, which acts like a piston on the second hub portion 2425. This causes the second hub portion 2425 to slide downward, as allowed by spring 2440. The pneumatic force on the second hub portion 2425 then appropriately balances (and exceeds) the resistive spring force of spring 2440 for actuation. Inflation shaft 2450 can also be used to inject fluids, such as water / saline / contrast media, etc., into the inflation cavity (between the outer and inner shafts) and balloon 2210.

[0157] Fig.25A and Fig.25BAn embodiment of a sheath system comprising an inner balloon sheath 2505 (or balloon catheter 2505) integrated with an outer guide sheath 2510 is shown. The guide sheath 2510 is coaxially and slidably positioned on the balloon sheath 2505 so that the balloon sheath is slidably and removably positioned inside the inner cavity of the guide sheath. The balloon sheath 2505 includes an expandable element, such as a balloon 2515, which can be converted between a contracted state and an expanded state. The balloon 2515 extends around the circumference of the outer wall of the sheath. Fig.25A The system in a first state or position is shown, wherein the guide sheath 2510 is positioned relative to the balloon sheath 2505 so that a portion of the guide sheath 2510 covers the balloon 2510 and constrains it in a contracted state. That is, the guide sheath 2510 covers the balloon 2215 so that the inner wall of the guide sheath 2510 prevents the balloon 2215 from expanding outward. The inner catheter 2505 includes a cavity extending between a proximal end and a distal end, and the distal end is suitable for receiving blood flow from the common carotid artery. The outer guide sheath and the inner catheter 2505 are suitable for being introduced jointly through the common carotid artery or other arteries, such as a puncture in the femoral artery. Any of the embodiments described herein can be introduced through the common carotid artery, the femoral artery or other arteries.

[0158] Fig.25B The system is shown in a second state or position, wherein the guide sheath 2510 is moved axially relative to the balloon sheath 2505 (along the long axis of the sheath, such as in a proximal direction or relative to the balloon sheath 2505). Fig.25B The guide sheath 2510 is moved to the right (or vice versa) so that the guide sheath 2510 no longer covers or constrains the balloon 2515. The relative movement between the guide sheath and the balloon sheath is through the movement of only the guide sheath, only the balloon sheath, or both the guide sheath and the balloon sheath. Fig.25BIn the embodiment of the present invention, the distal edge of the guide sheath 2510 is positioned proximal to the proximal edge of the balloon 2515. The balloon 2515 is free to expand outward, such as via inflation, via self-biasing or other mechanisms toward expansion. The balloon sheath 2505 may include a locking element, such as a threaded arrangement 2520, which is mechanically docked with a corresponding locking element 2525 (such as a corresponding thread) on the guide sheath 2510. That is, the outer wall of the balloon sheath 2505 has one or more threads that interact with the complementary threads on the inner wall of the locking element 2525 of the outer guide sheath 2510. In one embodiment, the locking element 2525 is an annular collar having a size of expanding outward relative to at least a portion of the outer guide sheath 2510, such as an adjacent area of ​​the outer guide sheath 2510 where the collar is located. The collar can rotate around the outer wall and / or long axis of the outer guide sheath 2510 relative to the rest of the outer guide sheath 2510. This allows the user to rotate the locking element 2525 and lock the thread of the guide sheath tube and the thread of the inner balloon catheter 2505. Therefore, the locking collar has a first set of threads on the inner wall of the locking collar, wherein the first set of threads engages the second set of threads on the outer wall of the inner catheter, and locks the position of the inner catheter relative to the outer guide sheath tube. In one embodiment, when the inner catheter is in the first position, the locking collar is aligned with the second set of threads on the guide sheath tube. In another embodiment, there is a third set of threads (or a continuous thread configuration along the inner catheter) on the guide sheath tube, wherein when in the second position, the locking collar is aligned with the threads.

[0159] Fig.25B A guide sheath 2510 is shown with a locking element 2525 of the guide sheath positioned to engage with the threads 2520 ( Fig.25A ) are locked together. Fig.25A In the illustrated configuration, the guide sheath 2510 can also protect the balloon 2515, such as during passage through tissue. As mentioned, the collar 2525 can be rotated to engage the threads with each other and lock the position of the guide sheath and balloon catheter relative to each other.

[0160] FIG. 26A to FIG. 26C Another embodiment of a sheath system is shown that includes a balloon sheath 2605 (or catheter) integrated with a guide sheath. Fig.26A , the sheath 2605 includes a window cover 2610 aligned with the inner balloon. As described in more detail below, the window cover 2610 can be a layer of material positioned between the outer shell of the sheath 2605 and the inner layer of the sheath. Fig.26AWindow cover 2610 is shown in a closed state such that window cover 2610 covers and constrains the internal balloon. Window cover 2610 includes a proximal region 2615 that can be actuated, such as by a user retracting proximal region 2615. This also retracts window cover 2610 proximally to reveal an opening in which balloon 2620 is positioned. Balloon 2620 is then inflated to an expanded state, such as Fig.26C Various mechanisms can be used to retract the window cover 2610, such as a slidable pull ring, a trigger, a screw mechanism, a button, etc.

[0161] Fig. 27 Show FIG. 26A to FIG. 26C Schematic cross-sectional view of one embodiment of a sheath 2605. The sheath 2605 includes an outer layer forming an outer shell 2705. A window layer 2710 (such as a polymer) is positioned inside the outer shell and forms a window cover 2610. A balloon layer 2715 is positioned inside the window layer 2710 and forms a balloon 2620. An intermediate layer 2720 is formed of a polymer and is positioned below the balloon layer 2715. An inflation cavity 2725 is formed between the intermediate layer 2720 and the inner layer 2730, which can be, for example, formed of a braid and / or a coil. An inner cavity 2740 is inside the sheath 2605.

[0162] Fig.28 Show FIG. 26A to FIG. 26C Schematic cross-sectional view of another embodiment of a sheath 2605. This embodiment of the sheath 2605 includes an outer layer forming an outer shell 2805. A balloon layer 2820 (such as a polymer) is positioned between the outer shell 2805 and the window layer 2815. An inflation lumen is positioned between the window layer 2815 and the inner layer 2825, which can be formed, for example, by a braid and / or a coil. An inner lumen 2830 is inside the sheath 2605.

[0163] Window layer 2710 (such as a polymer) is positioned inside the outer shell and forms window cover 2610. Balloon layer 2715 is positioned inside window layer 2710 and forms balloon 2620. Intermediate layer 2720 is formed of a polymer and positioned below balloon layer 2715. Inflation cavity 2725 is formed between intermediate layer 2720 and inner layer 2730, which can be, for example, formed of braid and / or coil. Inner cavity 2740 is inside sheath 2605.

[0164] Fig.29A and Fig.29B Another embodiment of a sheath 2805 (or inner balloon catheter) positioned in a blood vessel is shown. The sheath 2805 has a curved distal region, wherein the bend may be a fixed bend that remains in place unless action is taken to remove the bend. The bend may be the default state of the sheath, or may be achieved after placement in the blood vessel. Reference Fig.29A, the sheath 2805 includes a main lumen 2810 that opens at the distal end of the sheath 2805. The sheath also includes a secondary lumen 2815 that is parallel to the main lumen 2810. The secondary lumen 2815 forms a hole or opening 2820 that is positioned at a distance from the distal end of the sheath 2805. In an exemplary embodiment, the opening 2820 is 1-5 cm from the distal end of the sheath 2805, such as at the location of the bend or at 1-2 cm, 1-3 cm, or 2-3 cm. The inflatable balloon 2830 is joined or otherwise fixedly positioned adjacent to the opening 2820 within the secondary lumen 2815. When positioned as Fig.29A 2815, the balloon 2830 is in a reduced size, scaled state. The balloon 2830 can also be converted to be positioned outside the secondary cavity 2815, so that the balloon 2830 is positioned flush with the outer surface of the sheath 2805, so that the balloon blocks the opening 2820. The balloon 2820 can also be moved outward from the secondary cavity 2815 and to the outside of the sheath 2805 so that it engages the interior of the blood vessel, such as to occlude or at least partially occlude the blood vessel. The balloon 2830 is made of a compliant or semi-compliant material. For example, the balloon 2830 can be made of silicone, a polymer blend, urethane, Pellethane or other compliant materials. FIG. 29A to FIG. 30B The embodiments can be used with Fig.25A and Fig.25B The configuration shown in (or any other configuration) is used in combination to constrain balloon 2830.

[0165] During insertion of the sheath 2805 into a blood vessel, the balloon 2830 is structurally protected by being located within the secondary lumen 2815 or being tightened along the outer surface of the sheath 2805. Once positioned at the desired location in the blood vessel, the balloon 2830 can be inflated to an expanded state via the secondary lumen 2815, such as Fig.29B During inflation, balloon 2830 expands outward through opening 2820. Balloon 2830 can expand to the size of the occluded vessel. The balloon expands in a proximal direction while main lumen 2810 opens in a distal direction. This arrangement can allow for additional working space within the vessel. As mentioned, the balloon can be positioned at a bend. In one embodiment, the balloon is positioned at a bend such as Fig.29B The cavity 2810 inflates or extends outwardly in a direction opposite to the direction of the bend shown (or in a direction opposite to the direction in which the opening of the cavity 2810 faces).

[0166] Fig. 30A and Fig. 30B Another embodiment of a sheath 3005 positioned in a blood vessel is shown. Fig.29A and Fig.29B3010 or a dual lumen (not shown). The sheath 3005 has a distal opening 3015 at the distal end of the sheath 3005. The sheath 3005 also has a second opening 3020 that communicates with the lumen 3010 (in a single lumen configuration). The lumen 3010 can be used to deliver one or more treatments, such as, for example, a stent delivery system, an aspiration catheter, a stent retriever, etc., via the distal opening 3015.

[0167] The secondary opening 3020 can be used to deliver an occluding device 3030, which can be mounted on a tether, delivery wire, or delivery shaft 3035, such as Fig. 30B The delivery wire can be used to move the balloon inside and outside the sheath 3005 via the opening 3020. The occluding device can be any device that can be expanded to occlude a blood vessel. The occluding device 3030 can be deployed to occlude the blood vessel, followed by delivery of therapy via the distal opening 3015.

[0168] The configuration of the occluding device 3030 can be varied. For example, the occluding device can be a balloon on a delivery shaft 3035 formed by a thin wire or tube, which can be hollow to inflate the occluding device. The delivery shaft 3035 can have a J-shaped distal region (or other shapes) to pass through the secondary opening 3020. The shape of the occluding device 3030 can be varied. In another example, the occluding device 3030 is an umbrella or accordion-shaped device that is connected to an actuating element, such as a tensioning wire to expand the occluding device. A dilator can be used to facilitate the delivery of the delivery shaft 3035. Such a dilator can have an inner cavity through which the occluding device 3030 and the delivery shaft 3035 are deployed. The dilator can be used to guide the occluding system through the secondary opening 3020 to provide automatic entry into the blood and prevent the occluding system from hitting the vessel wall at a sharp angle. The dilator can also include a back-seepage indicator to confirm that the occluding system is properly inserted into the blood vessel. Fig. 30A and Fig. 30B The occlusion system shown can also be Fig.29A and Fig.29B Double-lumen sheath is shown for delivery.

[0169] Exemplary usage

[0170] The blood flow through the carotid bifurcation at different stages of the method of the present invention will be described. Initially, the distal sheath 605 of the arterial access device 110 (or any embodiment of the percutaneous sheath described herein) is introduced into the common carotid artery CCA. As mentioned, access to the common carotid artery CCA can be performed via a transcarotid or transfemoral approach and can be a direct surgical incision or a percutaneous approach. After the sheath 605 of the arterial access device 110 is introduced into the common carotid artery CCA, blood flow will continue to flow in the antegrade direction AG, where blood flow from the common carotid artery enters the internal carotid artery ICA and the external carotid artery ECA.

[0171] The venous return device 115 is then inserted into a venous return site, such as the internal jugular vein IJV or the femoral vein. The shunt 120 is used to connect the flow lines 615 and 915 (such as Figure 1A In this manner, the shunt 120 provides a path for retrograde blood flow from the arterial access device 110 to the venous return device 115. In another embodiment, the shunt 120 is connected to the external container 130 instead of the venous return device 115, such as Figure 1C shown.

[0172] Once all components of the system are in place and connected, blood flow through the common carotid artery CCA is stopped, such as by using an expandable occlusive element of a percutaneous sheath in the common carotid artery CCA. Alternatively, the occlusive element 129 is introduced on a second occlusive device 112 separate from the distal sheath 605 of the arterial access device 110, such as Figure 2B The ECA may also be occluded with a separate occluding element, which may be on the same device 110 or on a separate occluding device.

[0173] At that time, retrograde blood flow RG from the external carotid artery ECA and the internal carotid artery ICA will begin and flow through the sheath 605, the streamline 615, the shunt 120, and enter the venous return device 115 via the streamline 915. As described above, the flow control assembly 125 regulates the retrograde blood flow. While maintaining the retrograde blood flow, the stent delivery catheter 2110 (or other interventional device) is introduced into the sheath 605. The stent delivery catheter 2110 is introduced into the sheath 605 through the hemostatic valve 615 and the proximal extension 610. The stent delivery catheter 2110 is advanced into the internal carotid artery ICA, and the stent 2115 is deployed at the bifurcation B.

[0174] Optionally, when blood flow from the common carotid artery continues and the internal carotid artery remains blocked, measures can be taken to further loosen the emboli from the treatment area. For example, mechanical elements can be used to clean or remove loose or loosely attached plaque or other potential embolic debris in the stent, thrombolysis or other fluid delivery catheters can be used to clean the area, or other operations can be performed. For example, under retrograde blood flow, balloons, atherectomy or more stents can be used to treat stent stenosis. In another example, the occlusion balloon catheter may include a flow chamber or aspiration chamber or channel that is open on the proximal side of the balloon. Saline, thrombolytic agents or other fluids can be injected and / or blood and debris can be sucked or sucked out of the treatment area without the need for additional devices. Although the emboli released in this way will flow into the external carotid artery, the external carotid artery is usually not as sensitive to embolic release as the internal carotid artery. By prophylactically removing the potential emboli left behind, when blood flow to the internal carotid artery is reestablished, the risk of embolic release is even further reduced. Emboli may also be released under retrograde blood flow, allowing the emboli to flow through the shunt 120 to the venous system, a filter in the shunt 120 , or the container 130 .

[0175] After the bifurcation has cleared the embolus, the occlusive element 129 or, alternatively, the tourniquet 2105 may be released to reestablish antegrade blood flow, such as Fig.14 E. Then, the sheath 605 can be removed.

[0176] Before the sheath 605 is extracted at the end of the operation, a self-closing element can be deployed around the perforation in the common carotid artery wall. Usually, the self-closing element will be deployed at the beginning of the operation or near it, but optionally, the self-closing element can be deployed when the sheath is extracted, usually when released from the distal end of the sheath to the common carotid artery wall. It is advantageous to use the self-closing element because it greatly affects the rapid closure of the perforation in the common carotid artery when the sheath is extracted. This rapid closure can reduce or eliminate the accidental blood loss that occurs at the end of the operation or during the accidental removal of the sheath. In addition, this self-closing element can reduce the risk of arterial wall dissection during entry. In addition, the self-closing element can be configured to apply friction or other retaining forces on the sheath during surgery. Such retaining force is advantageous, and can reduce the chance of accidentally removing the sheath during surgery. The self-closing element eliminates the need for vascular surgery closure of the artery with sutures after removing the sheath, thereby reducing the need for a large surgical field, and greatly reducing the surgical skills required for surgery.

[0177] Although certain versions are described herein in detail to describe various embodiments of methods and apparatus, it should be understood that other versions, embodiments, methods of use and combinations thereof are also possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

1. A system for accessing and treating a carotid artery, the system comprising: an outer introducer sheath configured for percutaneous delivery into a carotid artery; an inner catheter movably positioned within the outer guide sheath, the inner catheter having an expandable element positioned on a distal region of the inner catheter, wherein the inner catheter includes a lumen extending between a proximal end and a distal end and adapted to receive blood flow from a common carotid artery, the outer guide sheath and inner catheter being adapted to be co-introduced into the common carotid artery, the expandable element being adapted to expand and occlude the common carotid artery; as well as a locking collar positioned on a proximal region of the outer guide sheath, the locking collar configured to rotate about an outer wall of the outer guide sheath, wherein the locking collar has a first set of threads on an inner wall of the locking collar, wherein the first set of threads engages a second set of threads on an outer wall of the inner catheter, and wherein rotation of the locking collar causes the first set of threads to engage the second set of threads and lock a position of the inner catheter relative to the outer guide sheath; wherein the inner catheter is movably positioned within the outer guide sheath between a first position and a second position, wherein in the first position the outer guide sheath is positioned relative to the outer guide sheath such that a portion of the outer guide sheath covers and constrains the expandable element in a contracted state, and in the second position the outer guide sheath does not constrain the expandable element, and wherein when the inner catheter is in the first position the locking collar is aligned with the second set of threads.

2. The system of claim 1, further comprising a shunt fluidly connected to the inner catheter, wherein the shunt provides a path for blood to flow from the inner catheter to a flashback site.

3. The system of claim 1, wherein the expandable element is a balloon that extends around the circumference of the outer wall of the sheath. The system of claim 1 , wherein the inner catheter has a bend at a distal region of the inner catheter.

5. The system of claim 4, wherein the expandable element is a balloon extendable from a hole in the inner catheter, wherein the hole is located at the bend.

6. The system of claim 5, wherein the balloon is fixedly attached to the inner catheter proximate the bend, and wherein the balloon is positionable entirely within the inner catheter.

7. The system of claim 6, wherein the balloon is fixedly attached to the inner catheter proximate the bend, and wherein the balloon is positionable flush with an outer wall of the inner catheter and the balloon occludes the hole at the bend.

8. The system of claim 5, wherein the distal end of the inner catheter has an opening, and wherein the opening faces in a first direction, and wherein the balloon extends outwardly from the hole in a direction opposite to the first direction.

9. The system of claim 5, wherein the balloon is positioned within the inner catheter adjacent to the opening.

10. The system of claim 5, wherein the balloon is attached to a delivery wire.

11. The system of claim 10, wherein the delivery wire has an inflation lumen through which the balloon can be inflated.

12. The system of claim 10, wherein the delivery wire can be used to move the balloon inside and outside of the inner catheter via the opening.

13. The system of claim 5, the inner catheter having a primary lumen and a secondary lumen, and wherein the balloon is at least partially positioned in the secondary lumen.

14. The system of claim 5, wherein the hole is located 1-5 cm from the distal end of the balloon catheter.

15. The system of claim 1, wherein the outer introducer sheath and inner catheter are adapted to be introduced together through a puncture in the common carotid artery.

16. The system of claim 1, wherein the locking collar has a dimension that expands outwardly relative to at least a portion of the outer introducer sheath.

17. The system of claim 1, wherein the system is configured for percutaneous delivery into the carotid artery via an access site in the femoral artery.

18. The system of claim 1, wherein the system is configured for percutaneous delivery into a carotid artery via an access site in the neck.

19. The system of claim 1, wherein the expandable element is corrugated.

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