Occlusion sheath designed for percutaneous vascular access

Abstract

The systems and methods are configured for vascular and / or neurointerventional procedures. The systems and methods allow safe and rapid access, including percutaneous access, to the carotid arteries, as well as cerebral or intracranial arteries, for the introduction of interventional devices, such as to treat disease conditions. The methods and devices may include vascular access and retrograde systems.

Description

Technical Field

[0001] The present disclosure generally relates to medical methods and devices. More specifically, the present disclosure 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. The present disclosure also relates to methods and systems for accessing and treating cerebral arterial vasculature, such as for the treatment of stroke, intracranial atherosclerotic disease (ICAD), transient ischemic attack (TIA), acute ischemic stroke (AIS), tandem lesions, ruptured and unruptured intracranial and extracranial aneurysm embolization, chronic occlusion, and other neurovascular disease states.

Summary of the Invention

[0002] Methods and devices for vascular and / or neurointerventional procedures are disclosed. The system and method enable safe and rapid access, including percutaneous access to the carotid artery, and further to the cerebral or intracranial arteries, for the introduction of interventional devices, such as for treating stroke and / or other disease states. The method and device include a vascular access and a retrograde system.

[0003] In one embodiment, a system is disclosed for use in accessing and treating the carotid artery, the system comprising: an outer guide sheath configured to be delivered percutaneously into the carotid artery; and an inner catheter movably disposed within the outer guide sheath, the inner catheter having an expandable element located in the distal region of the inner catheter, the inner catheter having a lumen extending between a proximal end and a distal end, adapted to receive blood flow from the 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 dilate and occlude the common carotid artery; and a locking collar located in the proximal region of the outer guide sheath, the locking collar being configured to rotate around the outer wall of the outer guide sheath. The locking collar comprises a locking collar having a first set of threads on the inner wall of the locking collar, the first set of threads engaging with a second set of threads on the outer wall of the inner catheter, and the locking collar rotates to engage the first set of threads with the second set of threads, thereby fixing the position of the inner catheter relative to the outer guide sheath, wherein the inner catheter is movably positioned inside the outer guide sheath between a first position in which the outer guide sheath is positioned relative to the outer guide sheath such that a portion of the outer guide sheath covers the expandable element and restrains it in a contracted state, and a second position in which the outer guide sheath does not restrain the expandable element, and when the inner catheter is in the first position, the locking collar is aligned with the second set of threads.

[0004] Other aspects, features, and advantages will become apparent from the following descriptions of various embodiments, which illustrate the principles of this disclosure as examples. [Brief explanation of the drawing]

[0005] [Figure 1A]Figure 1A is a schematic diagram of a retrograde blood flow system, including a flow control assembly, in which an arterial access device accesses the common carotid artery via a transcarotid approach and a venous return device communicates with the internal jugular vein. [Figure 1B] Figure 1B is a schematic diagram of a retrograde blood flow system in which an arterial access device accesses the common carotid artery via a transcarotid approach, and a venous return device connects to the femoral vein. [Figure 1C] Figure 1C is a schematic diagram of a retrograde blood flow system in which an arterial access device accesses the common carotid artery via a transfemoral approach, and a venous return device communicates with the femoral vein. [Figure 1D] Figure 1D is a schematic diagram of the retrograde blood flow system in which retrograde blood flow is collected in an external container. [Figure 2A] Figure 2A is a magnified view of the carotid artery in a state where the carotid artery is occluded by an occlusion element on the sheath and connected to a retrograde shunt, and an intervention device such as a stent delivery system or other working catheter has been introduced into the carotid artery via an arterial access device. [Figure 2B] Figure 2B shows an alternative system in which the carotid artery is occluded with another external occlusion device and connected to a retrograde shunt, and an intervention device such as a stent delivery system or other working catheter is introduced into the carotid artery via an arterial access device. [Figure 3] Figure 3 shows an alternative system in which the carotid artery is connected to a retrograde shunt, an intervention 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 using another occlusion device. [Figure 4] Figure 4 shows a normal cerebral circulation diagram including the ring of Willis. [Figure 5] Figure 5 shows the vascular system of the patient's neck, including the common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA), and internal jugular vein (IJV). [Figure 6A] Figure 6A shows an arterial access device useful in the method and system of this disclosure. [Figure 6B] Figure 6B shows a further arterial access device structure with a reduced distal end. [Figures 7A-7B] Figures 7A and 7B show tubing that can be used with the sheath in Figure 6A. [Figure 7C] Figure 7C shows an embodiment of the sheath stopper. [Figure 7D] Figure 7D shows the sheath stopper shown in Figure 7C, positioned on the sheath. [Figure 8A] Figure 8A shows the structure of an additional arterial access device with an expandable occlusion element. [Figure 8B] Figure 8B shows the structure of an additional arterial access device with an expandable occlusion element and a reduced distal end. [Figure 9A-9B] Figures 9A and 9B show further embodiments of the arterial access device. [Figure 9C-9D] Figures 9C and 9D show embodiments of valves on an arterial access device. [Figure 10A-10C] Figures 10A to 10C illustrate embodiments of venous return devices useful for the methods and systems of this disclosure. [Figure 11] Figure 11 shows an embodiment of a venous return device useful for the methods and systems of this disclosure. [Figure 12] Figure 12 shows the system from Figure 1, including the flow control assembly. [Figure 13] Figure 13 shows an embodiment of a variable flow resistance component useful for the methods and systems of this disclosure. [Figure 14] Figure 14 shows an embodiment of a variable flow resistance component useful for the methods and systems of this disclosure. [Figure 15A-15C] Figures 15A to 15C show schematic diagrams of one embodiment of the sheath 1505, which is configured for percutaneous access to and occlusion of blood vessels such as arteries. [Figures 16A-16B] Figures 16A and 16B show schematic diagrams of the distal region of one embodiment of a sheath configured for percutaneous access to and occlusion of blood vessels. [Figures 17A-17B]Figures 17A and 17B show a schematic view of the distal region of one embodiment of sheath 1705 configured for percutaneous access and occlusion of blood vessels. [Figure 18A] Figure 18A shows one embodiment of a sheath having a distal umbrella element. [Figure 18B] Figure 18B shows a cross-sectional view of the sheath of Figure 18A. [Figures 19A-19B] Figures 19A and 19B show another embodiment of an umbrella element on a sheath. [Figures 20A-20B] Figures 20A and 20B show the distal region of a sheath having an expandable element such as a balloon. [Figures 21A-21B] Figures 21A and 21B show another embodiment of a sheath including an expandable balloon. [Figures 22A-22C] Figures 22A - 22C show one embodiment of a sheath including an expandable balloon integrated within the outer wall of the sheath. [Figures 23A-23B] Figures 23A and 23B show the proximal hub of a sheath configured to control the tension configuration of a balloon. [Figures 24A-24B] Figures 24A and 24B show alternative mechanisms that can be coupled to a sheath to control the tension configuration of a balloon. [Figures 25A-25B] Figures 25A and 25B show one embodiment of a sheath system including a balloon sheath integrated with a guide sheath. [Figures 26A-26C] Figures 26A - 26C show another embodiment of a sheath system including a balloon sheath integrated with a guide sheath. [Figure 27] Figure 27 shows a schematic cross-sectional view of one embodiment of a sheath. [Figure 28] Figure 28 shows a schematic cross-sectional view of one embodiment of a sheath. [Figures 29A-29B] Figures 29A and 29B show one embodiment of a sheath disposed within a blood vessel. [Figures 30A-30B] Figures 30A and 30B show one embodiment of a sheath disposed within a blood vessel.

Best Mode for Carrying Out the Invention

[0006] The methods, devices, and systems disclosed herein establish and facilitate retrograde or reverse flow blood circulation in the carotid bifurcation region to restrict or prevent the release of embolus into the cerebrovascular system, particularly into the internal carotid artery. In non-limiting examples, these methods are particularly useful in interventional procedures such as stent placement and angioplasty, atherectomy, etc., performed through a transcarotid or transfemoral approach to the common carotid artery, either using an incisional surgical technique or a percutaneous technique such as a modified Seldinger technique or micropuncture technique. A wide variety of interventions, including the treatment of stroke, intracranial atherosclerosis (ICAD), transient ischemic attack (TIA), acute ischemic stroke (AIS), tandem lesions, ruptured and unruptured intracranial and extracranial artery embolism, chronic occlusion, intravascular lithotripsy (VLI), shock wave intravascular lithotripsy (IVL), and other neurovascular disease conditions, may be performed in conjunction with the systems and methods described herein.

[0007] Access to the common carotid artery (as shown in Figure 5) is established by placing an access sheath or other tubular access cannula into the lumen of the artery, typically with the distal end of the sheath positioned proximal to the junction or bifurcation B of the common carotid artery into the internal and external carotid arteries. Percutaneous sheaths may have an occlusion component at the distal end, such as a compliant occlusion balloon. A catheter or guidewire with an occlusion component, such as a balloon, can be passed through the access sheath and placed into the proximal external carotid artery (ECA) to prevent embolic entry, although occlusion of the external carotid artery is usually not necessary. A second return sheath is placed in the venous system, such as the internal jugular vein (IJV) or femoral vein (FV). The arterial access sheath and the venous return sheath are connected to each other to form an external arterial-venous shunt.

[0008] Retrograde blood flow can be established and adjusted according to the patient's condition. Blood flow through the common carotid artery is occluded by an external vascular loop or tape, an internal occlusion device such as a vascular clamp or occlusion balloon, or other types of occlusion means. When blood flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system causes blood to flow retrograde or in the reverse direction from the cerebral blood vessels through the internal carotid artery and through the shunt into the venous system.

[0009] Alternatively, the venous sheath may be omitted, and the arterial sheath may be connected to an external collection reservoir or receptacle. Retrograde blood flow is collected in the receptacle. If necessary, the collected blood may be filtered and returned to the patient during or after the procedure. The pressure in the receptacle may be released to atmospheric pressure so that blood flows backward from the cerebral blood vessels to the receptacle due to the pressure gradient, or the pressure in the receptacle may be negative.

[0010] If necessary, to achieve or enhance retrograde blood flow from the internal carotid artery, blood flow from the external carotid artery may be blocked by placing a balloon or other occlusion element in the external carotid artery, usually just above (i.e., distal to) the bifurcation within the internal carotid artery.

[0011] The procedures and treatments described below primarily concern carotid artery stenting, but it will be understood that the carotid artery access methods described herein are also useful for angioplasty, atherectomy, and other interventional procedures that may be performed in the carotid system, for example, near the bifurcation between the internal and external carotid arteries. Furthermore, it will be understood that some of these access, vascular occlusion, embolization, and protective methods are also applicable to other vascular interventional procedures, such as the treatment of acute stroke.

[0012] The disclosures herein include several specific embodiments for improving the performance of carotid artery access procedures. At least most of these individual embodiments and improvements may be performed individually or in combination with one or more other improvements to facilitate and enhance the performance of specific interventions in the carotid artery system.

[0013] Figure 1A shows a retrograde blood flow system 100 according to a first embodiment. The retrograde blood flow system 100 is configured to establish and promote retrograde or regurgitant blood circulation in the region of the carotid bifurcation in order to limit or prevent the release of embolus into the cerebrovascular system, particularly the internal carotid artery. The retrograde blood flow 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, in an alternative embodiment, another return site such as another large vein or external vessel). The retrograde blood flow system 100 includes an arterial access device 110, a venous return device 115, and a shunt 120 that provides a passage for regurgitation (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 configured to regulate and / or monitor reflux from the common carotid artery to the internal jugular vein, as described in more detail below. The flow control assembly 125 interacts with the flow path via the shunt 120 outside the flow path, inside the flow path, or both. As described in more detail below, the arterial access device 110 is inserted at least partially into the common carotid artery (CCA), and the venous return device 115 is inserted at least partially into a venous return site such as the internal jugular vein (IJV). The arterial access device 110 and the venous return device 115 are coupled to the shunt 120 at connection positions 127a, 127b. When blood flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system causes blood to flow retrograde or in the reverse RG direction (Figure 2A) from the cerebrovascular system through the internal carotid artery and the shunt 120 to the venous system. The flow control assembly 125 modulates, enhances, assists, monitors, and / or otherwise regulates retrograde blood flow.

[0014] In the embodiment shown in Figure 1A, the arterial access device 110 accesses the common carotid artery (CCA) via a transcarotid approach. Transcarotid access provides a short, untorquedable route from the vascular access point to the target treatment site, thereby reducing the time and difficulty of the procedure compared to, for example, a transfemoral approach. In one embodiment, the arterial distance (distance measured through the artery) from the arterial incision to the target treatment site is typically 15 cm or less. In one embodiment, the arterial distance may be 5–10 cm. Furthermore, this access route reduces the risk of embolism formation when passing through the anatomical structures of the affected, angular, or curvilinear aortic arch or common carotid artery. At least a portion of the venous return device 115 is positioned within the internal jugular vein (IJV). In one embodiment, transcarotid access to the common carotid artery is achieved percutaneously via a skin incision or puncture into which the arterial access device 110 is inserted. When an incision is used, the length of the incision may be approximately 0.5 cm. An occlusion element 129, such as an expandable balloon, may be used to occlude the common carotid artery (CCA) at a position proximal to the distal end of the arterial access device 110. The occlusion element 129 may be located on the arterial access device 110 or 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, the common carotid artery can be occluded using a tourniquet 2105. The tourniquet 2105 is shown by a dashed line to indicate that it is a device used in an optional surgical approach.

[0015] In another embodiment shown in Figure 1B, the arterial access device 110 accesses the common carotid artery (CCA) via a transcarotid approach, while the venous return device 115 accesses a venous return site other than the jugular vein, such as the femoral vein (FV). The venous return device 115 can be inserted into a central vein, such as the femoral vein (FV), via percutaneous puncture in the groin.

[0016] In another embodiment shown in Figure 1C, the arterial access device 110 accesses the common carotid artery via a femoral approach. According to the femoral approach, the arterial access device 110 accesses the common carotid artery (CCA) via percutaneous puncture to the femoral artery (FA), such as in the groin, and ascends the aortic arch (AA) to reach the target common carotid artery (CCA). The venous return device 115 can communicate with the jugular vein (JV) or the femoral vein (FV).

[0017] Figure 1D illustrates yet another embodiment in which the retrograde blood flow system 100 provides backflow from the carotid artery to the external container 130, rather than from the venous return site. The arterial access device 110 is connected to the external container 130 via a shunt 120 communicating with a flow control assembly 125. The backflow of blood is collected in the external container 130. If necessary, the blood can also be filtered and then returned to the patient. The pressure in the external container 130 may be set to zero pressure (atmospheric pressure) or even lower, thereby allowing blood to flow retrogradely from the cerebrovascular system to the external container 130. Optionally, to achieve or enhance backflow from the internal carotid artery, flow from the external carotid artery can be blocked by placing a balloon or other occlusion element in the external carotid artery, usually just above the bifurcation with the internal carotid artery. Figure 1D shows the arterial access device 110 positioned in a transcarotid approach via the common carotid artery (CCA), but it should be understood that the use of the external container 130 can also be used in arterial access devices 110 for transfemoral approaches.

[0018] Referring to the enlarged view of the carotid artery in Figure 2A, a therapeutic or interventional device, such as a stent delivery system 135 or other working catheter, may be introduced into the carotid artery via an arterial access device 110 or a percutaneous sheath, as will be described in detail below. The stent delivery system 135 may be used to treat plaque P, such as by placing a stent into the carotid artery. The arrow RG in Figure 2A indicates the direction of retrograde blood flow. In an alternative embodiment, as shown in Figure 2B, a clamp element is used to occlude the artery.

[0019] Figure 3 shows an alternative embodiment in which the occlusion element 129 may be introduced into the carotid artery on a second sheath (arterial occlusion device 112) separate from the distal sheath 605 of the arterial access device 110. The second sheath, i.e., the “proximal” sheath (arterial occlusion device 112), may be configured to be inserted into the common carotid artery in a proximal, i.e., “downward” direction, away from the cerebrovascular system. The second sheath, i.e., the proximal sheath, may generally include an inflatable balloon 129 or other occlusion elements as described above. The distal sheath 605 of the arterial access device 110 may then be positioned in the common carotid artery distal to the second sheath, i.e., the proximal sheath, and generally oriented distally toward the cerebrovascular system. By using the occlusion sheath and access sheath separately, the size of the arterial incision required for introducing the access sheath can be reduced.

[0020] <Description of anatomical structure> [Collateral cerebral circulation] The Circle of Willis (CW) is the major arterial anastomotic trunk of the brain, connecting all major arteries supplying blood to the brain—namely, the two internal carotid arteries (ICAs) and the vertebrobasilar system. Blood is delivered to the brain from the Circle of Willis via the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery. This communication between arteries enables collateral circulation through the brain. This allows blood flow through alternative routes, providing a safety mechanism in case one or more blood vessels supplying blood to the brain become blocked. In most cases, the brain can continue to receive adequate blood supply even if there is an occlusion somewhere in the arterial system (for example, if the internal carotid artery (ICA) is ligated as described herein). Blood flow through the Circle of Willis ensures adequate cerebral blood flow through numerous pathways that redistribute blood to the side that has been deprived.

[0021] The possibility of collateral circulation in the Circle of Willis is thought to depend on the presence and size of its constituent vessels. It is important to understand that there can be considerable anatomical differences between individuals in these vessels, and that many of the vessels involved may be diseased. For example, some individuals may be missing one of the communicating arteries. If an occlusion occurs in such individuals, collateral circulation may be impaired, leading to ischemia and potentially brain injury. Furthermore, the autoregulatory response to a decrease in perfusion pressure may include dilation of collateral arteries, such as the communicating arteries of the Circle of Willis. Adjustment time for this compensatory mechanism may be required before collateral circulation reaches a level that supports normal function. This autoregulatory response can occur over a period of 15–30 seconds and is only compensatory within a specific pressure range and a specific range of flow reduction. Therefore, a transient ischemic attack may occur during this adjustment period. A prolonged period of very high retrograde flow can result in insufficient blood flow to the patient's brain, potentially leading to intolerance in the patient, as manifested by neurological symptoms and, in some cases, transient ischemic attacks.

[0022] Figure 4 shows normal cerebral circulation and the formation of the Circle of Willis (CW). The aorta (AO) gives rise to the brachiocephalic artery (BCA), which branches into the left common carotid artery (LCCA) and the left subclavian artery (LSCA). The aorta (AO) further gives rise to the right common carotid artery (RCCA) and the right subclavian artery (RSCA). The left and right common carotid arteries (CCA) give rise to 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) supplies blood to part of the frontal lobe and the striatum. The middle cerebral artery (MCA) is a large artery with tree-like branches that supply blood to the entire lateral surface of each hemisphere of the brain. The left and right posterior cerebral arteries (PCA) originate from the basilar artery (BA) and supply blood to the posterior part of the brain (occipital lobe).

[0023] Anteriorly, the Circle of Willis is formed by the anterior cerebral artery (ACA) and the anterior communicating artery (ACoA), which connects the two anterior cerebral arteries (ACAs). The two posterior communicating arteries (PCoA) connect the Circle of Willis to the two posterior cerebral arteries (PCAs) and branch off from the basilar artery (BA) to complete the communicating arteries posteriorly.

[0024] The common carotid artery (CCA) also gives rise to the external carotid artery (ECA), which branches extensively and supplies blood to most structures of the head except for the brain and orbital contents. The external carotid artery (ECA) also serves to supply blood to the structures of the neck and face.

[0025] [Carotid artery bifurcation] Figure 5 shows a magnified view of the relevant vascular system in the patient's neck. The common carotid artery (CCA) branches at bifurcation B into the internal carotid artery (ICA) and the external carotid artery (ECA). Bifurcation B is located approximately at the level of the fourth cervical vertebra. Figure 5 shows plaque P formed at bifurcation B.

[0026] As described above, the arterial access device 110 can access the common carotid artery (CCA) via a transcarotid approach. Following the transcarotid approach, the arterial access device 110 is inserted into the common carotid artery (CCA) at the arterial access position L. This insertion may be, for example, a surgical incision or puncture of the wall of the common carotid artery (CCA). Typically, there is a distance D of about 5-7 cm between the arterial access position L and the bifurcation B. When the arterial access device 110 is inserted into the common carotid artery (CCA), it is undesirable for the distal tip of the arterial access device 110 to come into contact with the bifurcation B, as this may disrupt the plaque P and cause the formation of embolic particles. To minimize the possibility of the arterial access device 110 coming into contact with 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 the procedure.

[0027] The common carotid artery is enclosed on both sides by a layer of fascia called the carotid sheath. The carotid sheath also encloses the internal jugular vein and the vagus nerve. The sternocleidomastoid muscle is located anterior to the carotid sheath. Transcarotid access to the common carotid artery and internal jugular vein, either percutaneously or surgically, can be performed through the carotid sheath, just above the clavicle, between the two apexes of the sternocleidomastoid muscle, taking care to avoid the vagus nerve.

[0028] At the upper end of the carotid sheath, the common carotid artery branches into the internal and external carotid arteries. The internal carotid artery continues upward without branching, entering the skull and supplying blood to the retina and brain. The external carotid artery branches to supply blood to the scalp, face, eyeballs, and other surface structures. Several facial and cranial nerves intertwine around the arteries. Further neck muscles may overlap the bifurcation. These nerve and muscular structures are dissected and pushed aside during carotid endarterectomy to access the carotid bifurcation. In some cases, the carotid bifurcation is close to the level of the mandible, making access more difficult and reducing the room to isolate the bifurcation from the various nerves that need protection. In such cases, the risk of inadvertent nerve damage may increase, and open endarterectomy may not be an appropriate option.

[0029] Retrograde blood flow system As described above, the retrograde blood flow system 100 includes an arterial access device 110, a venous return device 115, and a shunt 120 that provides a passage for retrograde flow from the arterial access device 110 to the venous return device 115. The retrograde blood flow system 100 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 the components of the retrograde blood flow system 100 will now be described.

[0030] Arterial access devices Figure 6A shows an exemplary embodiment of an arterial access device 110, including a distal sheath 605, a proximal extension 610, a flow channel 615, an adapter, i.e., a Y-connector 620, and a hemostatic valve 625. The arterial access device may also include a dilator 645 with a tapered distal end 650 and an introducer guidewire 611. The arterial access device is used together with the dilator and introducer guidewire to access a blood vessel. The function 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 a sharp insertion angle, to enable non-traumatic and secure sheath insertion, and to limit the length of the sheath, sheath dilator, and introducer guidewire inserted into the blood vessel. The arterial access device 110 includes or may comprise any embodiment of the percutaneous sheath described herein.

[0031] The distal sheath 605 is configured to be introduced through an incision or puncture of the wall of the common carotid artery, for example, through a surgical incision or percutaneous puncture established using the Seldinger technique. The length of the distal sheath 605 may range from 5 cm to 15 cm, and is usually between 10 cm and 12 cm. The inner diameter of the distal sheath 605 is in the range of 7 Fr (1 Fr = 0.33 mm) to 10 Fr, and is usually 8 Fr. The distal sheath 605 is desirable to be very flexible while maintaining hoop strength to withstand twisting and buckling, especially when the sheath is introduced supraclavicular and below the carotid bifurcation via a transcarotid approach. Therefore, the distal sheath 605 may be circumferentially reinforced with braids, spiral ribbons, spiral wires, cut tubes, etc., and has an inner liner such that the reinforcing structure is sandwiched between the outer jacket layer and the inner liner. The inner liner may be made of a low-friction material such as PTFE. The outer jacket layer may be made of one or more materials from a group including polyether block amide copolymer (Pebax), thermoplastic polyurethane, or nylon. In one embodiment, the reinforcing structure or material, and / or the material or thickness of the outer jacket layer may vary depending on the longitudinal position of the distal sheath 605, thereby allowing for variations in flexibility along the length. In another embodiment, the distal sheath may be introduced into the femoral artery, such as in the groin, by percutaneous puncture and introduced through the aortic arch (AA) to the target common carotid artery (CCA).

[0032] As shown in Figure 6B (enlarged view of the distal region 630 of the distal sheath 605), the distal sheath 605 may have a stepped or other configuration with a reduced-diameter distal region 630. The distal region 630 of the sheath may be sized for insertion into the carotid artery and typically has an inner diameter in the range of 2.16 mm (0.085 inches) to 2.92 mm (0.115 inches). The remaining proximal region of the sheath has a larger outer diameter and lumen diameter, with an inner diameter 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 region (distal section) 630 has a length of approximately 2 cm to 4 cm. Because the length of the reduced-diameter distal region (distal section) 630 is relatively short, this section can be placed within the common carotid artery (CCA) via a transcarotid approach while reducing the risk of the distal end of the distal sheath 605 contacting bifurcation B. Furthermore, the reduced-diameter distal region (distal section) 630 also allows for a reduction in the size of the arterial incision required to introduce the distal sheath 605 into the artery, while minimizing the impact on the magnitude (level) of flow resistance. In addition, the reduced-diameter distal region (distal section) 630 may be more flexible, thereby allowing for a better fit to the lumen of the vessel.

[0033] Referring again to Figure 6A, the elongated proximal extension 610 has a lumen that is continuous with the lumen of the distal sheath 605. The lumen may be connected by a Y-connector 620 that connects the lumen of the channel 615 to the sheath. In the assembled system, the channel 615 connects to a backflow shunt (shunt 120) and forms the first shunt limb of the shunt 120 (see Figure 1). The proximal extension 610 may be long enough to sufficiently separate the hemostatic valve 625 from the Y-connector 620 adjacent to the percutaneous or surgical insertion site. By separating the hemostatic valve 625 from the percutaneous insertion site, the physician can introduce the stent delivery system or other working catheter into the proximal extension 610 and distal sheath 605 while it remains out of the fluoroscopic field of view during fluoroscopy. In one embodiment, the proximal extension 610 is approximately 16.9 cm from the most distal junction with the distal sheath 605 (e.g., the hemostatic valve 625) to the proximal end of the proximal extension 610. In one embodiment, the proximal extension has an inner diameter of 3.175 mm (0.125 inches) and an outer diameter of 4.445 mm (0.175 inches). In one embodiment, the wall thickness of the proximal extension is 0.635 mm (0.025 inches). The inner diameter may be, for example, in the range of 15.24 mm (0.60 inches) to 3.81 mm (0.150 inches), and the wall thickness may be in the range of 0.254 mm (0.010 inches) to 1.27 mm (0.050 inches). In another embodiment, the inner diameter may be in the range of, for example, 3.81 mm (0.150) inches to 6.35 mm (0.250) inches, and the wall thickness may be in the range of 0.635 mm (0.025 inches) to 2.54 mm (0.100) inches. The dimensions of the proximal extension may vary. In one embodiment, the proximal extension has a length in the range of about 12 cm to 20 cm. In another embodiment, the proximal extension has a length in the range of about 20 cm to 30 cm.

[0034] In one embodiment, the distance along the sheath from the hemostatic valve 625 to the distal tip of the distal sheath 605 is in the range of approximately 25 cm to 40 cm. In another embodiment, the distance is in the range of approximately 30 cm to 35 cm. By introducing a 2.5 cm sheath into the artery and configuring the system to allow an arterial distance of 5 to 10 cm from the arterial incision site to the target site, this system makes it possible to reduce the distance from the hemostatic valve 625 (the introduction position of the intervention device into the access sheath) to the target site, which is 32 to 43 cm, to a range of approximately 32.5 cm to 42.5 cm. This distance is about one-third of the distance required in the prior art.

[0035] A flush line 635 can be connected to the side of the hemostatic valve 625 and may have a stopcock 640 at its proximal or distal end. The flush line 635 allows for the introduction of saline solution, contrast agent, etc., during the procedure. The flush line 635 can also allow for pressure monitoring during the procedure. To facilitate the introduction of the distal sheath 605 into the common carotid artery, a dilator 645 having a tapered distal end 650 may be provided. The dilator 645 may be introduced through the hemostatic valve 625 such that the tapered distal end 650 extends through the distal end of the distal sheath 605 (see Figure 7A). The dilator 645 may have a central lumen for housing a guidewire. Typically, the guidewire is first placed in the vessel, and the dilator / sheath combination moves along the guidewire as it is introduced into the vessel.

[0036] Optionally, a sheath stopper 705, for example in the shape of a tube, may be provided coaxially on the outside of the distal sheath 605, as shown in Figure 7A. The sheath stopper 705 is configured to function as a sheath stopper to prevent the sheath from being inserted too deeply into the blood vessel. The sheath stopper 705 is sized and shaped to be positioned on the sheath body (distal sheath 605) so as to cover a portion of the sheath body (distal sheath 605) while leaving the distal portion of the sheath body (distal sheath 605) exposed. The sheath stopper 705 may have a flared proximal end (flange 710) that engages with the adapter (Y connector 620) and a distal end 715. Optionally, the distal end 715 may be configured at an angle, as shown in Figure 7B. The sheath stopper 705 can serve at least two purposes. Firstly, as shown in Figure 7A, the length of the sheath stopper 705 restricts the introduction of the distal sheath 605 into the exposed distal portion of the distal sheath 605, so that the sheath insertion length is limited to the exposed distal portion of the sheath. In one embodiment, the sheath stopper restricts the exposed distal portion to a range of 2 cm to 3 cm. In one embodiment, the sheath stopper restricts the exposed distal portion to 2.5 cm. In other words, the sheath stopper can restrict the insertion of the sheath into the artery to a range of approximately 2 cm to 3 cm, or up to 2.5 cm. Secondly, the sheath stopper 705 engages with a pre-positioned puncture closure device (if present) provided on the carotid artery wall, allowing the distal sheath 605 to be withdrawn without removing the closure device. The sheath stopper 705 may be manufactured from a transparent material so that the sheath body is clearly visible beneath the sheath stopper 705. The sheath stopper 705 may also be made of a flexible material, or the sheath stopper 705 may include joints or increased flexibility so that the sheath can bend as needed in the appropriate position when inserted into the artery. The sheath stopper may also be plastically bendable so that it can be bent into a desired shape so that it retains its shape when released by the user.The distal portion of the sheath stopper may be made from a harder material, and the proximal portion from a more flexible material. In one embodiment, the harder material is 85A durometer, and the more flexible portion is 50A durometer. In one embodiment, the distal 1-4 cm of the sheath stopper 705 is harder. The sheath stopper 705 may be removable from the sheath, and as a result, if the user desires a longer sheath insertion, the user can remove the sheath stopper 705, cut it shorter (the length of the sheath stopper), and reassemble the sheath stopper 705 on the sheath so that the longer insertable sheath length protrudes from the sheath stopper 705.

[0037] Figure 7C shows another embodiment of a sheath stopper 705 positioned adjacent to a sheath 605 in which an expander 645 is housed. The sheath stopper 705 is positioned adjacent to the sheath 605 in which the expander 645 is housed. The sheath stopper 705 in Figure 7C can deform from a first shape, such as a linear shape, to a second shape different from the first shape, and the sheath stopper maintains the second shape until sufficient external force acts on the sheath stopper to change its shape. The second shape may be, for example, a shape with a non-linear, curved, or other contour, or an irregular shape. For example, Figure 7C shows a sheath stopper 705 having multiple bends as well as a linear portion. Figure 7C is merely an example, and it should be understood that the sheath stopper 705 may be formed to have any number of bends along its longitudinal axis. Figure 7D shows the sheath stopper 705 positioned on the sheath 605. The sheath stopper 705 has higher rigidity than the distal sheath 605, such that the distal sheath 605 takes on a shape or contour that conforms to the contour shape of the sheath stopper 705.

[0038] The sheath stopper 705 can be shaped according to the angle of sheath insertion into the artery, and the depth of the artery or the patient's body habitus. This feature reduces the force on the tip of the sheath against the vessel wall, especially when the sheath is inserted into the vessel at a steep angle. The sheath stopper can be bent or otherwise deformed to help orient the sheath coaxially with the entering artery, even when the angle of entry into the arterial incision is relatively steep. The sheath stopper may be shaped by the operator before inserting the sheath into the patient. Alternatively, the sheath stopper may be shaped and / or reshaped in situ after the sheath has been inserted into the artery.

[0039] In another embodiment, as shown in Figure 9A, the sheath stopper 705 includes a distal base or distal flange 710 of a size and shape that distributes the force of the sheath stopper over a wider area of ​​the vessel wall, thereby reducing the risk of accidental insertion of the sheath stopper into the vessel through vessel damage or arterial incision. The flange 710 may have a round shape or other non-traumatic shape that is large enough to distribute the force of the sheath stopper over a wide area of ​​the vessel wall. In one embodiment, the flange is inflatable or mechanically expandable. For example, the arterial sheath and sheath stopper may be inserted into the surgical area through a small puncture of the skin and then expanded before the sheath is inserted into the artery.

[0040] The sheath stopper may include one or more notches or recesses 720 patterned in a staggered configuration along the length of the sheath stopper, thereby increasing the flexibility of the sheath stopper while maintaining axial strength that allows for an anterior force of the sheath stopper against the arterial wall. The recesses may also be used to facilitate securing the sheath to the patient via sutures in order to reduce sheath detachment. The sheath stopper may also include a connector element 730 at its proximal end that corresponds to the features of the arterial sheath, allowing the sheath stopper to be locked or unlocked to the arterial sheath. For example, the connector element may be a hub with a substantially L-shaped slot 740 corresponding to a pin 750 on the hub, creating a bayonet mount-style connection. In this way, the sheath stopper can be securely attached to the hub, reducing the possibility of the sheath stopper being inadvertently removed from the hub unless it is unlocked from the hub.

[0041] The distal sheath 605 may be configured to establish a curved transition from a generally anterior-posterior approach over the common carotid artery to a generally axial transition within the common carotid artery. Arterial access through the wall of the common carotid artery, whether by direct surgical incision or percutaneous access, may typically require a larger access angle than other arterial access sites. This is due to the fact that the insertion site in the common carotid artery is much closer to the treatment site (i.e., the carotid bifurcation) than other access points. A larger access angle is required to increase the distance from the insertion site to the treatment site, allowing the sheath to be inserted to the appropriate distance without the distal tip of the sheath reaching the carotid bifurcation. For example, in the case of transcarotid access, the sheath insertion angle is typically 30–45 degrees or more, while in the case of access to the femoral artery, the sheath insertion angle may be 15–20 degrees. Therefore, the sheath needs to bend more than is typically done with introducer sheaths, without twisting or applying excessive force to the opposite arterial wall. Furthermore, it is desirable that the tip of the sheath does not abut or contact the arterial wall in a manner that restricts flow into the sheath after insertion. The insertion angle of the sheath is defined as the angle between the lumen axis of the artery and the longitudinal axis of the sheath.

[0042] Another sheath configuration features a curved dilator inserted into a straight yet flexible sheath, with the dilator and sheath bending during insertion. The sheath retains sufficient flexibility to conform to the anatomical structure even after the dilator is removed.

[0043] In one embodiment, the sheath may incorporate a puncture-capable and non-traumatic tip similar to that of a guidewire. This eliminates the need to change needles and wires currently used for micropuncture arterial access, saving time, reducing blood loss, and lowering the need for surgeon skill.

[0044] Figure 8A shows an arterial access device 110 according to another embodiment. This embodiment is substantially the same as the embodiment shown in Figure 6A, except that the distal sheath 605 includes an occlusion element 129 for occluding flow, for example, through the common carotid artery. If the occlusion element 129 is an inflatable structure such as a balloon, the sheath 605 may include an inflation lumen communicating with the occlusion element 129. The occlusion element 129 may be an inflatable balloon, an inflatable cuff, a conical or other shaped peripheral element that expands radially outward and engages with the inner wall of the common carotid artery to block flow passing through it, a membrane-covered braid, a slotted tube that expands in diameter when compressed axially, or a similar structure that can be positioned by mechanical means. In the case of balloon occlusion, the balloon may have a variety of properties, such as flexibility, inflexibility, elasticity, high strength, or other properties. In one embodiment, the balloon is an elastic balloon that fits tightly to the outer circumference of the distal end of the sheath before inflation. When inflated, the elastic balloon expands and adheres to the inner wall of the common carotid artery. In one embodiment, the elastic balloon can expand to at least twice its diameter in the non-deployed configuration, and in many cases can be deployed to at least three times, more preferably at least four times, or more than the diameter in the non-deployed configuration.

[0045] As shown in Figure 8B, the distal sheath 605 with the occlusion element 129 may have a stepped or other configuration with a reduced-diameter distal region 630. The distal region 630 is sized to be insertable into the carotid artery, while the remaining proximal region of the sheath 605 has larger outer and luminal diameters. The lumen of the remaining proximal region of the sheath 605 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 length of the reduced-diameter distal region (distal section) 630 is approximately 2 cm to 4 cm. The relatively short length of the reduced-diameter distal region (distal section) 630 allows this section to be positioned into the common carotid artery (CCA) via a transcarotid approach, reducing the risk of the distal end of the sheath 605 contacting the bifurcation B.

[0046] When the insertion angle of the sheath is acute, as seen in transcarotid artery access procedures, and / or when the length of the sheath inserted into the artery is short, the distal tip of the sheath is likely to strike the vessel wall partially or entirely, thereby restricting flow into the sheath. In one embodiment, the sheath is configured to position its tip in the center of the lumen of the vessel. One such embodiment includes a balloon, such as the occlusion element 129 described above. In another embodiment, the balloon does not occlude flow, like an inflatable bumper, but still allows the tip of the sheath to be positioned away from the vessel wall. In another embodiment, an expandable mechanism is located at the tip of the sheath and is mechanically expanded when the sheath is in place. Examples of mechanically expandable features include braided structures, spiral structures, or longitudinal struts that expand radially when shortened.

[0047] In one embodiment, occlusion of the vessel near the distal tip of the sheath may be performed from the outside of the vessel, for example, by a Rummel's tourniquet or vascular loop near the sheath insertion site. In another embodiment, the occlusion device may be attached to the outside of the vessel around the sheath tip, and may be, for example, an elastic loop, an inflatable cuff, or a mechanical clamp that can be tightened around the vessel and the distal tip of the sheath. In retrograde blood flow systems, such vascular occlusion methods minimize the static blood flow area and reduce the risk of thrombus formation. Additionally, the tip of the sheath is aligned axially with the vessel and is not partially or completely blocked by the vessel wall.

[0048] Figures 9A to 9D show another arterial access device. In this configuration, the method of connection to the shunt differs from the configuration described above. Figure 9A shows the components of arterial access device 110, including an arterial access sheath (distal sheath 605), a sheath dilator 645, a sheath stopper 705, and a sheath guidewire 611. Figure 9B shows arterial access device 110 assembled for insertion into the carotid artery via the sheath guidewire 611. After the sheath is inserted into the artery, the sheath guidewire 611 and the sheath dilator 645 are removed during the procedure. In this configuration, the sheath has a sheath body (distal sheath 605), a proximal extension 610, and a proximal hemostatic valve 625 with a flush line 635 and a stopcock 640. The proximal extension 610 extends from a Y-adapter 660 to the hemostatic valve 625 to which the flush line 635 is connected. The sheath body (distal sheath 605) is made to be sized to be inserted into the carotid artery, and is the part that is actually inserted into the artery during use.

[0049] Instead of a Y-connector with a flow path connection ending with a valve, the sheath is provided with 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 is operable to open and close a fluid connection to a connector or hub 680 which can be detachably connected to a flow path such as a shunt. The valve 670 is located immediately adjacent to the lumen of the adapter 660, which communicates with the lumen of the sheath body (distal sheath 605). Figures 9C and 9D show cross-sectional details of the Y-adapter 660 with the valve 670 and hub 680. Figure 9C shows the valve closed relative to the connector. The position of the valve in Figure 9C is the position during the preparation of the arterial sheath. The valve is configured so that there is no possibility of air being trapped during the preparation of the sheath. Figure 9D shows the valve open relative to the connector. The position in Figure 9D is used when the shunt 120 is connected to the hub 680, allowing blood flow from the arterial sheath to the shunt. This configuration eliminates the need to prepare both a flush line and a flow path, instead allowing preparation from a single flush line 635 and stopcock 640. This single-point preparation is more familiar and convenient for the user, as it is the same as preparing a conventional introducer sheath without a shunt line connection. Furthermore, the absence of a flow path in the sheath makes preparation of the arterial sheath and handling during insertion into the artery easier.

[0050] Referring again to Figure 9A, the sheath may also include a second, more distal connector 690, separated from the Y-adapter 660 by a segment of the tube 665. The purpose of this second connector 690 and tube 665 is to allow the valve 670 to be positioned further proximal to the distal end of the sheath, while limiting the length of the insertable portion of the sheath 605, thereby reducing the level of radiation exposure the user receives when the shunt is connected to the arterial sheath during the procedure. In one embodiment, the distal connector (second connector 690) includes suture eyelets to help secure the sheath to the patient after placement.

[0051] During transcarotid revascularization (TCAR) procedures, the arterial sheath 605 may be inserted into the patient's common carotid artery (CCA). As described elsewhere in this specification, to achieve retrograde blood flow, the common carotid artery (CCA) can be occluded to stop antegrade blood flow from the aorta through the common carotid artery (CCA). Blood flow through the common carotid artery (CCA) may be occluded by an external vascular loop or tape, an internal occluding member such as a vascular clamp or balloon, or other types of occluding means. When blood flow through the common carotid artery (CCA) is blocked, the natural pressure gradient between the internal carotid artery (ICA) and the venous system causes blood to flow retrograde, i.e., backward, from the cerebrovascular system. Blood from the internal carotid artery (ICA) and external carotid artery (ECA) flows retrograde, and the system described herein allows the retrograde blood to flow through the flow controller 1130, the venous sheath 910, into the arterial sheath (distal sheath 605) and then back into the patient's femoral vein, as described elsewhere in this specification. Loose embolic material can be carried into the arterial sheath (distal sheath 605) with retrograde blood flow.

[0052] (Venous return device) Referring here to Figures 10A and 10B, the venous return device 115 may include a distal sheath 910 and a channel 915 that connects to the shunt 120 when the system is in use to form the shunt limb of the shunt 120. The distal sheath 910 is configured to be introduced to a venous return site, such as a jugular or femoral vein, through an incision or puncture. The distal sheath 910 and channel 915 may be permanently attached or may be attached using conventional Luer fittings, as shown in Figure 10A. Optionally, the distal sheath 910 may be connected to the channel 915 by a Y-connector 1005, as shown in Figure 10B. The Y-connector 1005 may include a hemostatic valve 1010. The venous return device also includes a venous sheath dilator 1015 and an introducer guidewire 611 to facilitate the introduction of the venous return device into the internal jugular vein or other vein. Similar to the arterial access dilator (dilater 645), the venous sheath dilater 1015 contains the lumen of the central guidewire, so the combination of venous sheath and dilater can be positioned on the guidewire 611. Optionally, the venous sheath (distal sheath 910) may include a flush line 1020 with a stopcock 1025 at its proximal or distal end.

[0053] Figures 10C and 11 show alternative configurations. Figure 10C shows the components of a venous return device 115, including a venous return sheath (distal sheath) 910, a venous sheath dilator 1015, and a sheath guidewire 611. Figure 11 shows the venous return device 115 assembled for insertion into a central vein via the 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 channel 915. A stopcock 1025 at the end of the flow channel allows the venous sheath to be flushed through the flow channel before use. This configuration allows the sheath to be prepared from a single point, similar to a conventional introducer sheath. Connection to the shunt 120 is made using a connector 1030 on the stopcock 1025.

[0054] To reduce the overall flow resistance of the system, the arterial access channel 615 (Figure 6A) and the venous return channel 915, as well as the Y-connectors 620 (Figure 6A) and 1005, may each have a relatively large 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). Low flow resistance of the system is desirable because it allows for maximizing flow in some procedures where the risk of embolism is highest. Due to the low flow resistance of the system, it is also possible to use variable flow resistance to control the flow within the system, as will be explained in more detail below. The dimensions of the venous return sheath (distal sheath) 910 may be approximately the same as those described above for the arterial access sheath (distal sheath 605). An extension of the hemostatic valve 1010 is not required for the venous return sheath.

[0055] (Retrograde shunt) The shunt 120 may be formed of a single tube or multiple connected tubes that provide fluid communication between an arterial access device 110 (arterial access catheter) and a venous return catheter (venous return device 115), providing a pathway for retrograde blood flow between them. As shown in Figure 1A, the shunt 120 connects at one end (via a connector at connection position 127a) to the flow path 615 of the arterial access device 110 and at the other end (via a connector at connection position 127b) to the flow path 915 of the venous return catheter (venous return device 115).

[0056] In one embodiment, the shunt 120 may be formed of at least one tube communicating with a flow control assembly 125. The shunt 120 may have any structure that provides a fluid path for blood flow. The shunt 120 may have a single lumen or multiple lumen. The shunt 120 may be detachably attached to the flow control assembly 125, the arterial access device 110, and / or the venous return device 115. Before use, the user can select the shunt 120 of the length best suited for use at the arterial access and venous return locations. 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 nature of the shunt 120 allows the user to lengthen the shunt 120 as needed depending on the venous return site. For example, in some patients, the internal jugular vein (IJV) may be small and / or tortuous. Because this area is close to other anatomical structures, it may have a higher risk of complications than other areas. Furthermore, a hematoma in the neck can cause airway obstruction and cerebrovascular complications. Therefore, for such patients, it may be desirable to locate the venous return site in a location other than the internal jugular vein (IJV), such as the femoral vein. Femoral vein return can be performed percutaneously with a low risk of serious complications and also provides alternative venous access to a central vein if the IJV is unavailable. In addition, femoral vein return alters the layout of the reflux shunt, allowing the shunt control device to be placed closer to the interventional "work area" where the device is introduced and the contrast injection port is located.

[0057] In one embodiment, the shunt 120 has an inner diameter of 4.76 mm (3 / 16 inch) and a length of 40 to 70 cm. As previously mentioned, the length of the shunt is adjustable. In one embodiment, the connector between the shunt and the arterial access device and / or venous access device is configured to minimize flow resistance. In one embodiment, the arterial access sheath (arterial access device 110), the regurgitation shunt (shunt 120), and the venous return sheath (venous return device 115) are combined to create an arteriovenous shunt (AV shunt) with low flow resistance, as shown in Figures 1A to 1D. As described above, the connections and flow paths of all these devices are optimized to minimize or reduce flow resistance. In one embodiment, the AV shunt has a flow resistance that allows for a maximum flow of 300 mL / min when there is no device present in the arterial access device 110 (arterial access sheath) and the AV shunt is connected to a fluid source with blood viscosity and a static pressure head of 60 mmHg. The actual shunt resistance varies depending on the presence or absence of a check valve (valve 1115) and filter 1145 (see Figure 12), as well as the length of the shunt, and flow rates of 150-300 mL / min may be possible.

[0058] When a device such as a stent delivery catheter is present within the arterial sheath, the flow resistance increases in a portion of the arterial sheath, thus increasing the overall flow resistance of the AV shunt. This increase in flow resistance leads to a corresponding decrease in flow. In one embodiment, a Y-arm (Y-connector 620), as shown in Figure 6A, connects the arterial sheath body (distal sheath 605) to a flow path 615 located some distance from the hemostatic valve 625 into which the catheter is introduced. This distance is determined by the length of the proximal extension 610. Therefore, the portion of the arterial sheath restricted by the catheter is limited by the length of the sheath body (distal sheath 605). The actual flow restriction depends on the length and inner diameter of the sheath body (distal sheath 605) and the outer diameter of the catheter. As mentioned above, the sheath length is in the range of 5 cm to 15 cm, usually 10 cm to 12 cm, and the inner diameter is usually in the range of 7 Fr (1 Fr = 0.33 mm) to 10 Fr, usually 8 Fr. The size of the stent delivery catheter may range from 3.7 Fr to 5.0 Fr, or from 3.7 Fr to 6.0 Fr, depending on the stent size and manufacturer. This limitation can be further reduced by designing the sheath body so that the inner diameter of the non-vascular portion (stepped sheath body) is larger, as shown in Figure 6B. Since flow restriction is proportional to the fourth power of the lumen distance, a slight increase in lumen area or annular area significantly reduces flow resistance.

[0059] The actual flow rate of an arteriovenous shunt (AV shunt) when in use varies further depending on the patient's cerebral blood pressure and flow resistance. [Flow control assembly (regulation and monitoring of retrograde blood flow)] The flow control assembly 125 interacts with the retrograde shunt (shunt 120) to regulate and / or monitor the flow rate of retrograde blood flow from the common carotid artery to the venous return site (e.g., femoral vein, internal jugular vein) or to the external container 130. In this respect, the flow control assembly 125 allows the user to achieve higher maximum flow rates than existing systems and to selectively adjust, set, or regulate the flow rate of retrograde blood flow. Various mechanisms may be used to regulate the flow rate of retrograde blood flow. The flow control assembly 125 allows the user to configure retrograde blood flow in a manner suitable for various treatment plans, as described below.

[0060] Figure 12 shows an example of system 100 and a schematic diagram of the flow control assembly 125. The flow control assembly 125 is positioned along the shunt 120 such that retrograde blood flow passes through or communicates with at least a portion of the flow control assembly 125. The flow control assembly 125 may include various controllable mechanisms for regulating and / or monitoring the retrograde blood flow. These mechanisms may include, for example, one or more pumps 1110, valves 1115, syringes 1120, and / or variable flow resistance components 1125 as various means for controlling the retrograde blood flow. The flow control assembly 125 may be manually controlled by the user or automatically controlled via the controller 1130 to change the flow through the shunt 120. For example, the flow rate of retrograde blood flow through the shunt 120 may be controlled by changing the flow resistance. 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 communicates with the components of the flow control assembly 125.

[0061] Furthermore, the flow control assembly 125 may include one or more flow sensors 1135 and / or anatomical data sensors 1140 (details below) for sensing one or more aspects of retrograde blood flow. A filter 1145 may be positioned along the shunt 120 to remove embolus before blood is returned to the venous return site. If the filter 1145 is positioned upstream of the controller 1130, the filter 1145 can prevent thrombi from entering the controller 1130 and potentially clogging the variable flow resistance component 1125. The various components of the flow control assembly 125 (including the pump 1110, valve 1115, syringe 1120, variable flow 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 positions relative to each other. The positions of the components of the flow control assembly 125 are not limited to those shown in Figure 12. Furthermore, the flow control assembly 125 does not necessarily include all components, but rather may include various subcombinations of components. For example, a syringe may be optionally used within the flow control assembly 125 for the purpose of adjusting the flow rate, or it may be used outside the assembly for purposes other than flow rate adjustment, such as introducing a fluid such as a radiopaque contrast agent into an artery in the anterograde direction via the shunt 120.

[0062] Both the variable flow resistance component 1125 and the pump 1110 may be connected to the shunt 120 to control the flow rate of retrograde blood flow. The variable flow resistance component 1125 controls the flow resistance, and the pump 1110 provides positive displacement of blood through the shunt 120. That is, the pump can be activated rather than relying on the perfusion stump pressure and venous back pressure of the external carotid artery (ECA) and internal carotid artery (ICA) to drive retrograde blood flow. The pump 1110 may be a peristaltic tube pump or any type of pump, including a positive displacement pump. The pump 1110 may be started and stopped (manually or automatically via the controller 1130) to selectively achieve the movement of blood through the shunt 120 and to control the flow rate through the shunt 120. The movement of blood through the shunt 120 may be achieved by other means, including the use of the suction syringe 1120, or by using a suction source (e.g., a vacuuminer, backlock syringe, or wall aspiration). Pump 1110 can communicate with controller 1130.

[0063] One or more flow control valves 1115 may be positioned along the shunt path. The valves may be manually actuated or automatically actuated (via a controller 1130). The flow control valves 1115 may be, for example, one-way valves that prevent anterograde flow in the shunt 120, check valves, or high-pressure valves that close the shunt 120 during, for example, high-pressure contrast agent injection (injections intended to enter the arterial vascular system in the anterograde direction). In one embodiment, the one-way valve is, for example, a low-flow-resistance valve disclosed in U.S. Patent No. 5,727,594, or other low-resistance valves.

[0064] In an embodiment of a shunt comprising both a filter 1145 and a one-way check valve (flow control valve 1115), the one-way check valve (flow control valve 1115) is located downstream of the filter 1145. In this embodiment, if there is debris moving within the shunt, the debris is captured by the filter 1145 before reaching the one-way check valve (flow control valve 1115). Many check valve configurations include a sealing member that seals against the housing containing the flow lumen. Debris can get trapped between the sealing member and the housing, which can impair the valve's ability to seal against reverse pressure.

[0065] The controller 1130 can communicate with components of system 100, including the flow control assembly 125, to enable manual and / or automatic adjustment and / or monitoring of retrograde blood flow through the components of system 100 (e.g., the shunt 120, arterial access device 110, venous return device 115, and 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 control may include a switch, dial, or similar component located directly on the controller 1130, or it may include a component located away from the controller 1130 (e.g., a foot pedal or similar device). The controller 1130 can also automatically control the components of system 100 without requiring input from the user. In one embodiment, a user may program software on the controller 1130 to enable such automatic control. The controller 1130 can control the operation of the mechanical parts of the flow control assembly 125. The controller 1130 may include circuitry or programming for interpreting signals generated by sensors 1135 and 1140, thereby enabling the controller 1130 to control the operation of the flow control assembly 125 in response to the signals generated by the sensors.

[0066] The representation of the controller 1130 shown in Figure 12 is for illustrative purposes only. It should be understood that the appearance and structure of the controller 1130 are subject to change. In Figure 12, the controller 1130 is shown as being integrated into a single housing. This allows the user to control the flow control assembly 125 from a single location. It should be noted that any component of the controller 1130 may be separated into individual housings. Furthermore, Figure 12 shows the controller 1130 and the flow control assembly 125 in separate housings. It should be noted that the controller 1130 and the flow control assembly 125 may be integrated into a single housing or divided into multiple housings or components.

[0067] [Flow Rate Status Indicator] The controller 1130 may include one or more indicators that provide the user with visual and / or audible signals regarding the state of retrograde blood flow. Audible instructions have the advantage of notifying the user of the state of retrograde blood flow without requiring the user to visually confirm the controller 1130. The indicators may include a speaker 1150 and / or a light 1155, or other means, for informing the user of the state of retrograde blood flow. The controller 1130 can communicate with one or more sensors of the system to control the activation of the indicators. Alternatively, the activation of the indicators may be directly linked to the user activating one of the flow control actuators 1165. The indicators are not limited to speakers or lights. The indicators may simply be buttons or switches that visually indicate the state of retrograde blood flow. For example, a button being in a specific state (e.g., pressed or lowered) may visually indicate that retrograde blood flow is high (high flow rate). Alternatively, a switch or dial that points to a specific labeled flow state may be used to visually indicate when retrograde blood flow is in that labeled state.

[0068] [Flow actuator] The controller 1130 may include one or more actuators that the user presses, switches, operates, or otherwise activates to adjust or monitor the flow rate of retrograde blood flow. For example, the controller 1130 may include a flow control actuator 1165 (e.g., one or more buttons, knobs, dials, switches) that the user can operate to selectively change the mode of retrograde blood flow. For example, in the illustrated embodiment, the flow control actuator 1165 is a knob that can be turned to various individual positions corresponding to the controller 1130 to realize specific retrograde blood flow states in the system 100. Retrograde blood flow states include, for example, (a) off, (b) low flow rate, (c) high flow rate, (d) suction, etc. It should be understood that these states are merely illustrative and different states or combinations of states may be used. The controller 1130 realizes various retrograde blood flow states by interacting with one or more components of the system, including sensors, valves, variable flow resistance components, and / or pumps. It should be noted that the controller 1130 also includes circuits and software for adjusting and monitoring retrograde blood flow, thus eliminating the need for the user to actively operate the controller 1130.

[0069] The OFF state corresponds to a state where there is no retrograde blood flow through the shunt 120. When the user sets the flow control actuator 1165 to OFF, the controller 1130 stops retrograde blood flow by shutting off the valve or closing the stopcock in the shunt 120. The low flow state corresponds to a low retrograde blood flow rate, and the high flow state corresponds to a high retrograde blood flow rate. When the user sets the flow control actuator 1165 to a low or high flow rate, the controller 1130 interacts with the components of the flow control assembly (flow control regulator) 125, including the pump 1110, valve 1115, and / or variable flow resistance component 1125, to increase or decrease the flow rate accordingly. Finally, the suction state corresponds to opening the circuit to a suction source (e.g., a vacuuminer or suction unit) when active retrograde blood flow is required.

[0070] This system allows for the alteration of blood flow between various states, including active, passive, suction, and off states. The active state corresponds to a system that uses means to actively drive retrograde blood flow. Such active means include, for example, pumps, syringes, and vacuum sources. The passive state corresponds to when retrograde blood flow is driven by perfusion stump pressure in the external carotid artery (ECA) and internal carotid artery (ICA), and possibly venous pressure. The suction state corresponds to a system that uses a suction source (e.g., a vacuuminer or suction unit) to promote retrograde blood flow. The off state corresponds to a state where retrograde blood flow in the system is zero, for example, as a result of closing a stopcock or valve. Low and high flow rates are either passive or active flow states. In one embodiment, specific values ​​for low and / or high flow rates (e.g., values ​​in ml / min) may be predetermined and / or pre-programmed in the controller, so that the user does not actually need to set or input these values. Rather, the user simply selects "high flow rate" and / or "low flow rate" (for example, 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 so that the flow rate achieves a predetermined high flow rate or low flow rate value. In another embodiment, the user sets or inputs low flow rate and / or high flow rate values ​​to the controller, etc. In another embodiment, the low flow rate and / or high flow rate are not actually set. Rather, external data (e.g., data from an anatomical data sensor 1140) is used as the basis for influencing the flow rate.

[0071] The flow control actuator 1165 may consist of multiple actuators. For example, one actuator (e.g., a button or switch) may switch the state from low flow rate to high flow rate, and another actuator may close and turn off the flow loop, for example, when the contrast agent is directed anterogradely into the carotid artery during contrast agent injection. In one embodiment, the flow control actuator 1165 may include multiple 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 flow, and a third actuator (e.g., a stopcock) may be operated to perform aspiration using a syringe. In another example, one actuator may be operated to switch to a low flow rate, and another actuator may be operated to switch to a high flow rate. Alternatively, the flow control actuator 1165 may include multiple actuators for switching the state from low flow rate to high flow rate, and an additional actuator for fine-tuning the flow rate within a range between the high flow rate state and the low flow rate state. Such an additional actuator may be used to fine-tune the flow rate within these states when switching between low and high flow rates. Thus, it should be understood that various flow rates can be set and fine-tuned within each state (i.e., high flow and low flow conditions). Various actuators can be used to achieve control of the flow state.

[0072] The controller 1130 or its individual components may be positioned in various locations relative to the patient and / or other components of the system 100. For example, to facilitate access to the flow control actuator 1165 during tool introduction, the flow control actuator 1165 may be positioned near the hemostatic valve through which the intervention tool is introduced to the patient. As shown in Figures 1A-1C, the positioning may differ, for example, depending on whether a transfemoral approach or a transcarotid approach is used. The controller 1130 may have wireless and / or length-adjustable wired connections to the rest of the system 100 to enable remote control of the system 100. The controller 1130 may have wireless and / or length-adjustable wired connections to the flow control assembly (flow control regulator) 125 to enable remote control of the flow control assembly (flow control regulator) 125. The controller 1130 may be integrated into the flow control assembly (flow control regulator) 125. If the controller 1130 is mechanically connected to a component of the flow control assembly 125, a tether with mechanical actuation capabilities may connect the controller 1130 to one or more components. In one embodiment, the controller 1130 may be positioned at a sufficient distance from the system 100 so that the controller 1130 can be positioned outside the radiation field when used for fluoroscopy.

[0073] The controller 1130 and any of its components can exchange information with other components of the system (e.g., pumps, sensors, shunts, etc.) in various ways. For example, any of various mechanical connections may be used to enable communication between the controller 1130 and system components. Alternatively, the controller 1130 can communicate with system components electronically or magnetically. Electromechanical connections may also be used. The controller 1130 may be equipped with control software that enables the controller to implement control functions using system components. The controller itself may be a mechanical, electrical, or electromechanical device. The controller may be mechanically, pneumatically, or hydraulically actuated (e.g., in the case of solenoid operation in flow control conditions), or it may be electromechanically actuated. The controller 1130 may include computer functions, computer processor functions, memory functions, and data storage functions.

[0074] Figure 13 shows an exemplary embodiment of a variable flow control element (variable flow resistance component 1125). In this embodiment, the flow resistance through the shunt 120 can be changed by providing two or more alternative paths to create low-resistance and high-resistance paths. As shown in Figure 13, the flow through the shunt 120 passes through the main lumen 1700 and the secondary lumen 1705. The secondary lumen 1705 is longer and / or smaller in diameter than the main lumen 1700. Therefore, the flow resistance of the secondary lumen 1705 is greater than that of the main lumen 1700. By allowing blood to pass through both the main lumen 1700 and the secondary lumen 1705, the flow resistance is minimized. Due to the pressure drop that occurs in the main lumen 1700 across the inlet and outlet of the secondary lumen 1705, blood can flow through both the main lumen 1700 and the secondary lumen 1705. This has the advantage of preventing blood stagnation. As shown in Figure 14, by blocking the flow through the main lumen 1700 of the shunt 120, the flow is completely diverted to the secondary lumen 1705, resulting in increased flow resistance and reduced blood flow rate. It is understood that additional flow lumens may be provided in parallel to allow for three, four, or more individual flow resistances. The shunt 120 may be provided with a valve 1710 that controls the flow to the main lumen 1700 and the secondary lumen 1705. The position of the valve may be controlled by an actuator (e.g., a button or switch) on the housing of the flow control assembly 125. The embodiments in Figures 13 and 14 have the advantage of maintaining accurate lumen size even at the lowest flow rate setting. The size of the secondary lumen may be configured to prevent thrombus formation even under the lowest flow rate or prolonged flow conditions. In one embodiment, the inner diameter of the secondary lumen 1705 is approximately 1.6 mm (0.063 inches) or larger.

[0075] In one embodiment, the connectors connecting the elements of the retrograde blood flow system are large-bore quick-connect connectors. For example, as shown in Figure 9B, a male large-bore hub 680 on the Y-adapter 660 of the arterial sheath (arterial access device 110) connects to a female corresponding hub 1320 on the arterial side of the shunt 120. Similarly, as shown in Figure 10C, a male large-bore connector 1310 on the venous side of the shunt 120 connects to a female corresponding connector 1310 in the flow path of the venous sheath (venous return device 115). The connections are standard female and male Luer connectors or other styles of tubular connectors.

[0076] [Sensor] As described above, the flow control assembly 125 comprises, or can communicate with, one or more sensors that communicate with the system 100 and / or acquire information from the patient's anatomical structure. Each sensor may be configured to respond to a physical stimulus (e.g., heat, light, sound, pressure, magnetism, motion, etc.) and transmit a resulting signal (output signal) for measurement and display or for the operation of the controller 1130. In one embodiment, the flow sensor 1135 interacts with the shunt 120 to sense the characteristics of the flow through the shunt 120 (e.g., blood flow velocity or volumetric flow rate). The flow sensor 1135 may be directly connected to a display that directly displays the volumetric flow rate or flow velocity value. Alternatively, the flow sensor 1135 may transmit data to the controller 1130 to display the volumetric flow rate or flow velocity.

[0077] There are various types of flow sensors 1135. The flow sensor 1135 may be a mechanical device (e.g., a paddle wheel, a flapper valve, a rolling ball, or any mechanical part that responds to the flow through the shunt 120). The movement of the mechanical device in response to the flow through the shunt 120 may function as a visual representation of the fluid flow, or it may be adjusted (calibrated) to a scale that serves as a visual representation of the fluid flow rate. The mechanical device may be coupled to an electrical component. For example, the paddle wheel may be positioned in the shunt 120 such that the fluid flow rotates the paddle wheel, and the faster the paddle wheel rotates, the greater the fluid flow rate. The paddle wheel may be magnetically coupled to a Hall effect sensor so that its rotational speed can be detected, thereby indicating the flow rate of the fluid passing through the shunt 120.

[0078] The system 100 is not limited to the use of a flow sensor 1135 located within the shunt 120, or a sensor that interacts with a venous return device 115 or an arterial access device 110. For example, an anatomical data sensor 1140 may communicate with or otherwise interact with the patient's anatomical structure (e.g., the patient's neurological structure). In this way, the anatomical data sensor 1140 may sense measurable anatomical characteristics directly or indirectly related to the flow rate of retrograde blood flow from the carotid artery. For example, the anatomical data sensor 1140 may measure the blood flow state in the brain (e.g., the flow velocity of the middle cerebral artery) and transmit that state to a display and / or controller 1130 to adjust the flow rate of retrograde blood flow based on predetermined criteria. In one embodiment, the anatomical data sensor 1140 includes transcranial Doppler ultrasound (TCD), which is an ultrasound examination that uses reflected sound waves to evaluate blood flowing in the brain. Using TCD, a TCD signal is generated that can be communicated to controller 1130, thereby allowing the retrograde blood flow rate to be controlled to achieve or maintain a desired TCD profile. The anatomical data sensor 1140 may be based on any physiological measurements, including retrograde blood flow rate, blood flow through the middle cerebral artery, TCD signals of embolic particles, or other neuromonitoring signals.

[0079] As another safety mechanism, the controller 1130 includes a timer 1170 (Figure 12) that records the time during which the flow rate was high. The controller 1130 may be programmed to automatically return the system 100 to a low flow rate after a predetermined period of high flow rate (e.g., 15 seconds, 30 seconds, or 60 seconds or more). After the controller returns to a low flow rate, the user may initiate another predetermined period of high flow rate as needed. Furthermore, the user may override the controller 1130 to transition the system 100 to a low (or high) flow rate as needed.

[0080] Exemplary Embodiment of a Transdermal Sheath Figure 15A shows a schematic diagram of one embodiment of a sheath 1505 configured for percutaneous access to and occlusion of a blood vessel, such as an artery (e.g., the common carotid artery). The sheath 1505 (or any of the plurality of sheaths described herein) may be configured in accordance with or as a complement to the arterial access device 110 described above. The sheath 1505 has an internal lumen and a distal tip 1502. The sheath 1505 has a distal region 1510 which includes an expandable portion 1515 configured to expand radially outward when placed in a blood vessel to occlude or partially occlude the vessel. The expandable portion 1515 includes a plurality of corrugations or other similar structures (such as an accordion-like structure or corrugated body that expands and contracts along its length) that can transition between a condensed state and an expanded state, the expanded state being suitable for occlusion (or partial occlusion) of a blood vessel. In one embodiment, the expandable portion 1515 is a braid or mesh (such as Nitinol) having a coating such as a polymer coating positioned on or covering the braid or mesh. In any of the multiple embodiments described herein, the sheath may have one or more angled shapes such as bends or curves to facilitate central positioning of the distal end within a blood vessel. Such one or more bends may have an acute or steep angle with respect to the long axis of the sheath, or they may have a soft curve. Such one or more bends may be positioned within or very close to the balloon at the distal end distal to the expandable element such as the balloon.

[0081] The expandable portion 1515 can be coupled to one or more elongated actuator elements, such as tension wires, extending to the proximal end of the sheath 1505 through a small or appropriately sized lumen within the wall of the sheath 1505. One or more actuator elements are coupled to control elements, such as a tension ring 1525, on the proximal hub 1525 of the sheath 1505. The proximal hub 1525 may include a flush port 1517.

[0082] The expandable portion 1515 can be transitioned between a contracted state (Figure 15B) and an expanded state (Figure 15C) by applying or removing tension (or compressive force) to the expandable portion 1515 via the actuator element 1520 and the tension ring 1525. When a force (tension or compressive force) is applied, the expandable portion 1515 expands radially into an enlarged disc shape that, when positioned within a blood vessel, occludes the vessel. When the force is removed, the expandable portion 1515 relaxes and returns to a flat state, allowing the sheath to be removed from the blood vessel. Depending on the mechanism, the blood vessel is occluded or released by increasing or decreasing the applied force.

[0083] The expandable portion 1515 can be subjected to force (tension or compression) by acting on the tension ring 1525 via a screw or pulley system, etc. It should be understood that other mechanisms for generating and reducing tension may also be used, such as a stretch and lock system, advancement / retraction of braids / mesh in / out of polymer material, or other means known in the art.

[0084] Figure 16A shows a schematic diagram of the distal region of one embodiment of a sheath 1605 configured for percutaneous access to and occlusion of a blood vessel. This embodiment includes one or more wings or flaps 1610 positioned in the distal region of the sheath 1605. The flaps 1610 are attached to the outer region of the sheath 1605 in a base region 1612. One or more expandable members 1615 (such as multiple balloons) are positioned in or near the base region 1612 between the inner surface of the flap and the outer surface of the sheath. In the deflated state, the flaps 1610 are positioned coplanar or substantially coplanar with the outer surface of the sheath 1605 such that the flaps 1610 do not contribute to, or contribute minimally to, the diameter of the sheath 1605.

[0085] The flap 1610 can transition to an expanded state (Figure 16B), where it cantilevers outward from the sheath 1605. This is due to the expandable member 1615 transitioning to a larger size, pushing the flap 1610 into the expanded state. The expandable member 1615 can transition to a larger size, for example, by being inflated through one or more expansion lumens within the sheath 1605. To transition back to a deflated state, the expandable member 1615 is deflated to a smaller size. The flap closes, allowing the sheath to be withdrawn from the blood vessel. The flap 1610 may be used in combination with any of the multiple expandable elements described herein (such as expandable balloons).

[0086] The flap may be made from any of a variety of materials, such as polymer materials, polymer-coated fabrics, or other non-porous materials, that can prevent blood from flowing through the blood vessel and occlude it. One or more flaps may overlap each other around the outer circumference of the sheath to allow for complete circumferential occlusion of the blood vessel.

[0087] Figure 17A shows a schematic diagram of the distal region of one embodiment of a sheath 1705 configured for percutaneous access to and occlusion of blood vessels. This embodiment includes an expandable umbrella element 1710 (indicated by dashed lines) in the distal region, which extends in annular manner around the entire circumference of the sheath. The umbrella element 1710 transitions between a contracted state, as shown in Figure 17A, and an expanded state, as shown in Figure 17B. The umbrella can be made from a variety of materials, such as nitinol or stainless steel (frame), or polymer, polymer-coated fabric, or other non-porous material (cover). The umbrella element 1710 includes or is attached to one or more tethers 1715 (such as wires or rods) extending from the umbrella element 1710 to the proximal hub of the sheath 1705, and the user can actuate the tethers 1715 to control the expansion and contraction of the umbrella element 1710. The tether 1715 is actuated by pushing, twisting, turning (screwing), or other mechanisms at the proximal hub, moving the umbrella-shaped element between an expanded and contracted state. As the wires advance distally, they act to cause the umbrella-shaped element to open (i.e., expand) and occlude the blood vessel. The tether may have sufficient columnar strength to allow the user to push the tether so that it imparts force to the umbrella-shaped element.

[0088] In the embodiments of Figures 17A and 17B, the umbrella element is located on the outer surface of the sheath 1705. In the retracted, compressed, or non-expanded state shown in Figure 17A, the umbrella element is positioned coplanar or substantially coplanar with the outer surface of the sheath so that it does not substantially increase the outer size of the sheath. One or more tethers 1715 can be advanced distally (to the left relative to Figures 17A and 17B) to apply force to the umbrella element. As the tethers 1715 advance, the most distal tip of the umbrella element remains fixed to the sheath, while the proximal region of the umbrella element moves distally. This causes the umbrella element 1710 to open radially into a conical, biconical, or other expanded shape. The tethers can be retracted to close the umbrella element.

[0089] Figure 18A shows another embodiment of the umbrella element 1810 on the sheath 1805. In this embodiment, the umbrella element 1810 is positioned between the outer sheath layer 1815 and the coaxial inner sheath layer 1820, as shown in the cross-sectional view of Figure 18B. The umbrella element 1810 is attached to one or more tethers 1830 that can advance the umbrella element so as to slide distally outward from between the outer sheath layer 1815 and the coaxial inner sheath layer 1820. The umbrella element expands outward into an expanded state. Once the umbrella element 1810 is removed from the sheath, the umbrella element can be made from a shape memory wire such as Nitinol that expands radially outward. The tethers 1830 can be retracted by sliding the umbrella between the outer sheath layer 1815 and the coaxial inner sheath layer 1820 or by pulling it back into the sheath.

[0090] Figures 19A and 19B show another embodiment of the umbrella element 1910 on the sheath 1905. In this embodiment, the umbrella element consists of a frame 1920 coupled to a plurality of push wires (or similar, e.g., a plurality of rods) 1930 extending toward the proximal hub. The metal frame 1920 and the plurality of push wires 1930 can be slidably positioned between the inner sheath layer and the outer sheath layer.

[0091] The umbrella-shaped element 1910 can be made from a deformable material such as fabric or polymer and is positioned on the outside of the sheath 1905. The umbrella-shaped element 1910 includes a slotted track 1935. When the frame 1920 is pushed distally (via a plurality of push wires 1930), a plurality of arms of the frame 1920 are pushed out and slide along the slotted track 1935. This allows the umbrella-shaped element to be expanded, as shown in Figure 19B.

[0092] Figures 20A and 20B show the distal region of the sheath 2005. An expandable element, such as the balloon 2010, is connected to the distal region of the sheath 2005. The balloon 2010 is shown in the expanded state in Figures 20A and 20B so that it flares outward from the outer wall or distal edge of the sheath 2005, allowing the balloon 2010 to at least partially occlude the blood vessel. The inner and outer walls of the sheath 2005 can be formed to form an annular cavity that accommodates the balloon 2010 in a confined or unexpanded state. Alternatively, the balloon 2010 can be confined within the inner lumen of the sheath 2005 when confined. In this way, the sheath 2005 can protect the balloon 2010 during insertion of the sheath 2005 into a blood vessel, etc.

[0093] The balloon 2010 can be modified in its configuration. For example, in one embodiment, the balloon 2010 is made solely of a compliant or malleable material configured to expand to a desired shape when inflated (for example, through one or more expansion lumens within the sheath 2005).

[0094] In another embodiment, the balloon includes or is connected to one or more actuating elements 2015 that can be actuated to transition the balloon into an expanded shape. These actuating elements may be, for example, a plurality of wires attached to or molded within the balloon. Using the plurality of wires, the balloon 2010 can be pushed out from the distal region of the sheath 2005, thereby inflating the balloon into an expanded state. One or more wires may include, for example, a shape-memory material (such as nitinol) that provides a scaffolding structure for the desired shape of the balloon 2010 in the expanded state. The balloon can be deflated and pulled back into the sheath using the plurality of wires, thereby transitioning the balloon 2010 into a constrained state, such as during withdrawal of the sheath 2005 from the blood vessel.

[0095] In another embodiment, the balloon 2010 is formed around one or more shape-memory wires, and when the balloon expands, it flares outward toward the blood vessel wall. When the balloon deflates, vacuum pressure guides the multiple wires back into the sheath.

[0096] Figures 21A and 21B show another embodiment of the distal region of the sheath 2005, which includes an expandable balloon 2110 formed by a compliant ring integrated into the outer wall of the sheath 2105. The balloon 2110 is a deformable annular structure extending circumferentially around the outer wall of the sheath. The sheath 2005 includes one or more expansion lumens that can be used to expand the balloon (shown in Figure 21A) from a constrained state or a smaller size shape to an expanded shape (shown in Figure 21B). The expansion lumens may be coaxial or asynchronous with the sheath. In the manufacturing method, the balloon is attached to the sheath 2005 using a laser bonding process. A laser is used to heat the balloon material and fuse or bond the balloon to the distal region of the sheath. In one embodiment, the balloon may be made from a flexible compliant material, and the sheath may be made from a polymer.

[0097] Figures 22A–22C show another embodiment of the distal region of the sheath 2205, including an expandable balloon 2210 integrated into the outer wall of the sheath 2205. For example, the balloon 2210 may be seated on the outer wall, or at least partially positioned within the outer wall, such as between the inner and outer layers of the outer wall of the sheath. The expandable balloon 2210 is bonded to the outer wall so that the balloon 2210 does not increase the diameter of the sheath when it is in a contracted or unexpanded state, as shown in Figure 22A. The balloon 2210 is made of a compliant material that can be stretched along the long axis of the sheath 2205, as shown in Figure 22A, which shows the balloon 2210 in an expanded state (stretched along the length of the sheath). This expanded configuration eliminates or reduces folds or wavy shapes in the balloon. Furthermore, the stretched configuration applies tension to the balloon 2210 so that the outer diameter of the balloon 2210 (and sheath 2205) becomes smaller or minimized during insertion of the sheath 2205 into the blood vessel, etc.

[0098] Referring to Figure 22B, by releasing or otherwise removing the tension on balloon 2210, the length of balloon 2210 along the longitudinal axis of sheath 2205 becomes shorter than the stretched configuration shown in Figure 22A. When balloon 2210 is untensioned, the material of balloon 2210 can expand radially outward. Balloon 2210 is then inflated (through one or more expansion lumens within sheath 2205, etc.), thereby allowing balloon 2210 to transition to an expanded state with a larger outer diameter, as shown in Figure 22C.

[0099] The stretched configuration of balloon 2210 shown in Figure 22A can be achieved in various ways. For example, the attached portion of balloon 2210 can be stretched by pulling back the outer portion of sheath 2205 (as indicated by arrow 2215). The outer portion of sheath 2205 can then be secured in place using locking elements such as latches, screws, locks, or hooks located at the proximal hub of sheath 2205.

[0100] Herein, we describe a non-limiting example of a mechanism that may be coupled to the sheath 2205 to control the tension configuration of the balloon 2210. Figure 23A shows a first mechanism 2305 incorporated into, or otherwise coupled to, a proximal hub 2302 of the sheath 2205, which includes an inner shaft 2310 and a coaxial outer shaft 2315 slidable relative to the inner shaft 2310. The hub 2302 includes 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 sealed relationship between the first component 2320 and the second component 2325. The balloon is attached to the outer shaft 2315 at its proximal end and to the inner shaft 2310 at its distal end, thereby allowing the balloon 2210 to be positioned in a stretched configuration by relative movement between the inner shaft 2310 and the outer shaft 2315. The hub 2302 also includes an inflation path 2335 which can be used to inflate the balloon 2210.

[0101] Figure 23B shows a perspective view of the second component 2325. The second component 2325 has an elongated body 2340 slidably positioned within a cavity 2345 (Figure 23A) in the first component 2320, thereby allowing the second component 2325 to slide along the long axis of the sheath 2205 relative to the first component 2320, as indicated by arrow A in Figure 23A. Referring to Figure 23B, the body 2340 of the second component 2325 has a travel path 2350 in which the pin 2355 of the first component 2320 is positioned. The travel path 2350 and the pin 2355 are engaged with each other so as to jointly define the slidable movement between the first component 2320 and the second component 2325.

[0102] Before the balloon 2210 inflates, the hub 2302 is actuated by moving the first component 2320 relative to the second component 2325. This creates a relative movement between the inner shaft 2310 (attached to the balloon 2210) and the outer shaft 2315 (also attached to the balloon 2210), allowing the user to selectively position the balloon 2210 in a taut configuration (as shown in Figure 22A) or an untaut configuration (as shown in Figure 22B). When the balloon 2210 is in an untaut configuration, it can be inflated via the inflation path 2335.

[0103] Figures 24A and 24B (not to exact scale) show alternative mechanisms that may be connected to the sheath 2205 to control the tension configuration of the balloon 2210. Figure 24A shows the balloon 2210 in a deflated state, and Figure 24B shows the balloon 2210 in an expanded state. The hub 2405 is located in the proximal region of the sheath 2205 and includes an access device such as a Luer element 2415 that provides access to the internal 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.

[0104] The second hub portion 2425 is slidably positioned within the internal cavity of the first hub portion 2420. The second hub portion 2425 can move within the cavity along the long axis of the sheath 2205. The second hub portion 2425 divides the internal cavity into a proximal portion 2435 and a distal portion 2440. A biasing element, such as a spring 2440, is positioned within the second hub portion 2425 and biases the second hub portion 2425 toward the proximal portion 2435 of the internal cavity. A seal may be positioned to provide a sealed separation between the proximal portion 2435 and the distal portion 2440. In addition, an expansion shaft 2450 communicates with the proximal portion 2435 and the balloon 2210.

[0105] Spring 2440 applies constant tension to the outer shaft 2315 via the second hub portion 2425 so that the balloon 2210 is maintained in its default contracted state as shown in Figure 24A. In this state, the balloon 2210 is stretched along its length. The balloon 2210 can be inflated via the expansion shaft 2450, thereby expanding the balloon 2210 outward and retracting the outer shaft 2315 proximal to the side as shown in Figure 24B. The expansion of the balloon via the expansion shaft 2450 also increases the pressure in the cavity 2435, and this pressure acts like a piston on the second hub portion 2425. This causes the second hub portion 2425 to slide downward as permitted by spring 2440. To actuate it, the air pressure on the second hub portion 2425 is balanced (and exceeds) the resistance spring force of spring 2440. Furthermore, the inflation shaft 2450 can be used to inject fluids such as water, saline solution, or contrast agent into the inflation lumen (between the outer shaft and the inner shaft) and the balloon 2210.

[0106] Figures 25A and 25B show one embodiment of a sheath system including an inner balloon sheath 2505 (or balloon catheter 2505) integrated with an outer guide sheath 2510. The guide sheath 2510 is coaxially and slidably positioned over the balloon sheath 2505 so that the balloon sheath is slidably and detachably positioned inside the inner lumen of the guide sheath. The balloon sheath 2505 includes an expandable element such as a balloon 2515 that can transition between a deflated state and an expanded state. The balloon 2515 extends around the outer circumference of the outer wall of the sheath. Figure 25A shows the system in a first state or first position, where the guide sheath 2510 is positioned relative to the balloon sheath 2505 such that a portion of the guide sheath 2510 covers the balloon 2515 and restrains it in a deflated state. That is, the guide sheath 2510 covers the balloon 2215 such that the inner wall of the guide sheath 2510 restrains the balloon 2215 from expanding outward. The internal catheter 2505 includes a lumen extending between its proximal and distal ends, the distal end being fitted to receive blood flow from the common carotid artery. The external guide sheath and internal catheter 2505 are fitted to be introduced together through a puncture in the common carotid artery or another artery such as the femoral artery. Any of the multiple embodiments described herein may be introduced through the common carotid artery, femoral artery, or other artery.

[0107] Figure 25B shows the system in a second state or second position, where the guide sheath 2510 has been moved axially relative to the balloon sheath 2505 (proximal or to the right relative to Figure 25B, etc., along the long axis of the sheath) (or vice versa) such that the guide sheath 2510 no longer covers or restrains the balloon 2515. The relative movement between the guide sheath and the balloon sheath is achieved by the movement of the guide sheath alone, the balloon sheath alone, or both the guide sheath and the balloon sheath. The distal edge of the guide sheath 2510 is therefore positioned proximal to the proximal edge of the balloon 2515 in Figure 25B. The balloon 2515 expands freely outward via inflation, via self-biasing toward expansion, or via other mechanisms, etc. The balloon sheath 2505 may include a locking element, such as a threaded structure 2520, which mechanically connects to a corresponding locking element 2525 (such as a plurality of corresponding threads) on the guide sheath 2510. That is, the outer wall of the balloon sheath 2505 has one or more threads that interact with 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 that extends outward with respect 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 positioned. The collar can rotate around the outer wall and / or long axis of the outer guide sheath 2510 with respect to the rest of the outer guide sheath 2510. This allows the user to rotate the locking element 2525 and engage the threads of the guide sheath in a lockable manner with the threads of the inner balloon catheter 2505. Therefore, the locking collar has a first set of threads on its inner wall, which engage with a second set of threads on the outer wall of the inner catheter, thereby fixing the position of the inner catheter relative to the outer guide sheath. In one embodiment, the locking collar is aligned with the second set of threads on the guide sheath when the inner catheter is in the first position.In another embodiment, there is a third set of threads (or a continuous thread configuration along the inner catheter) on the guide sheath, and the locking collar is aligned with the threads when in the second position.

[0108] Figure 25B shows a guide sheath 2510 in which the locking element 2525 of the guide sheath is positioned to lock with the threads 2520 (Figure 25A) of the balloon sheath. In the configuration shown in Figure 25A, the guide sheath 2510 can also protect the balloon 2515 as it passes through tissue, for example. As described above, the collar 2525 can be rotated to engage their threads with each other, thereby fixing the relative positions of the guide sheath and the balloon catheter relative to each other.

[0109] Figures 26A–26C show another embodiment of the sheath system, including a balloon sheath 2605 (or catheter) integrated with a guide sheath. Referring to Figure 26A, the sheath 2605 includes a window cover 2610 aligned with the internal balloon. As will be described in more detail below, the window cover 2610 can be a layer of material placed between the outer housing of the sheath 2605 and the inner layer of the sheath. Figure 26A shows the window cover 2610 in a closed state so that it covers and restrains the internal balloon. The window cover 2610 includes a proximal region 2615 that can be actuated by the user, for example, by retracting the proximal region 2615. This also retracts the window cover 2610 proximal to expose the opening in which the balloon 2620 is located. The balloon 2620 can then be inflated to its expanded state, as shown in Figure 26C. Various mechanisms such as a sliding pull tab, trigger, screw mechanism, or button can be used to retract the window cover 2610.

[0110] Figure 27 shows a schematic cross-sectional view of one embodiment of the sheath 2605 shown in Figures 26A-26C. The sheath 2605 includes an outer layer that forms the outer housing 2705. A window layer 2710 (such as polymer) is located inside the outer housing and forms the window cover 2610. A balloon layer 2715 is located inside the window layer 2710 and forms the balloon 2620. An intermediate layer 2720 is formed from polymer and is located below the balloon layer 2715. An expansion lumen 2725 is formed between the intermediate layer 2720 and the inner layer 2730 and may be, for example, made of braid and / or coil. An inner lumen 2740 is located inside the sheath 2605.

[0111] Figure 28 shows a schematic cross-sectional view of another embodiment of the sheath 2605 of Figures 26A-26C. This embodiment of the sheath 2605 includes an outer layer forming the outer housing 2805. A balloon layer 2820 (such as polymer) is located between the outer housing 2805 and the window layer 2815. An expansion lumen is located between the window layer 2815 and the inner layer 2825 and can be formed, for example, by braiding and / or coiling. The inner lumen 2830 is located inside the sheath 2605.

[0112] A window layer 2710 (made of polymer, etc.) is located inside the outer housing and forms a window cover 2610. A balloon layer 2715 is located inside the window layer 2710 and forms a balloon 2620. An intermediate layer 2720 is made of polymer and is located below the balloon layer 2715. An expansion lumen 2725 is formed between the intermediate layer 2720 and the inner layer 2730 and may be, for example, a braid and / or coil. An inner lumen 2740 is located inside the sheath 2605.

[0113] Figures 29A and 29B show another embodiment of the sheath 2805 (or internal balloon catheter) placed in a blood vessel. The sheath 2805 has a bent distal region, and the bend may be a fixed bend that remains in place unless acted upon to remove the bend. The bend may be the default state of the sheath, or the bend may be achieved after placement in a blood vessel. Referring to Figure 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 adjacent to the main lumen 2810. The secondary lumen 2815 forms a hole or opening 2820 located at a distance from the distal end of the sheath 2805. In exemplary embodiments, the opening 2820 is located 1 to 5 cm from the distal end of the sheath 2805, for example, at a bend, or 1 to 2 cm, 1 to 3 cm, or 2 to 3 cm from the distal end of the sheath 2805. The inflatable balloon 2830 is positioned adjacent to the opening 2820, either bonded to the inside of the secondary lumen 2815 or otherwise fixed in place. When positioned inside the secondary lumen 2815 as shown in Figure 29A, the balloon 2830 is in a deflated state of reduced size. The balloon 2830 may also be positioned outside the secondary lumen 2815 so that the balloon closes the opening 2820 by being coplanar (flush) with the outer surface of the sheath 2805. The balloon 2820 may be further moved outside the secondary lumen 2815 and outside the sheath 2805 so as to occlude the vessel by engaging with the inside of the vessel, or at least partially occlude it. The balloon 2830 is made from a compliant or semi-compliant material. For example, the balloon 2830 may be made from silicone, polyblende, urethane, pelletane, or other compliant material. The embodiments in Figures 29A–30B can be used in conjunction with the configurations shown in Figures 25A and 25B (or any other embodiment) to restrain the balloon 2830.

[0114] While the sheath 2805 is inserted into the blood vessel, the balloon 2830 is structurally protected by being inside the secondary lumen 2815 or by being taut along the outer surface of the sheath 2805. Once positioned in the desired location within the blood vessel, the balloon 2830 can be inflated through the secondary lumen 2815 to a expanded state, as shown in Figure 29B. During inflation, the balloon 2830 expands outward through the opening 2820. The balloon 2830 can expand to a size that occludes the blood vessel. The balloon expands proximal, while the main lumen 2810 opens distally. This structure can provide additional working space within the blood vessel. As described above, the balloon can be positioned in a bend. In one embodiment, the balloon expands or extends outward from the sheath in the opposite direction to the bend (or the opposite direction to the direction the opening of the lumen 2810 faces), as shown in Figure 29B.

[0115] Figures 30A and 30B show another embodiment of the sheath 3005 placed inside a blood vessel. This embodiment is similar to the embodiments in Figures 29A and 29B, except that the sheath 3005 may have a single lumen 3010 or a double lumen (not shown). The sheath 3005 has a distal opening 3015 at its distal end. 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 a stent delivery system, a suction catheter, or stent retriever, through the distal opening 3015.

[0116] The secondary opening 3020 can be used to deliver an occlusion device 3030, which may be mounted on a tether, delivery wire, or delivery shaft 3035, as shown in Figure 30B. The delivery wire can be used to move the balloon in and out of the sheath 3005 through the opening 3020. The occlusion device can be any device expandable to occlude a blood vessel. The occlusion device 3030 can be positioned to occlude a blood vessel and then deliver the treatment through the distal opening 3015.

[0117] The occlusion device 3030 can be modified in configuration. For example, the occlusion device is a balloon on a delivery shaft 3035 formed of a thin wire or tube, and can be hollow for inflation of the occlusion device. The delivery shaft 3035 may have a J-shaped distal region (or other shape) to facilitate passage through the secondary opening 3020. The shape of the occlusion device 3030 can be modified. In another example, the occlusion device 3030 is an umbrella-shaped or accordion-shaped device coupled to an actuation element such as multiple tension wires for expansion of the occlusion device. A dilator can be used to facilitate the delivery of the delivery shaft 3035. Such a dilator has an inner lumen through which the occlusion device 3030 and the delivery shaft 3035 can be positioned. The dilator can be used to guide the occlusion system through the secondary opening 3020 so that the occlusion system can enter the blood vessel automatically and prevent it from hitting the vessel wall at an acute angle. The dilator may also be equipped with a bleed-back indicator to confirm that the occlusion system has been properly inserted into the blood vessel. The occlusion system shown in Figures 30A and 30B can also be delivered via a double-lumen sheath, as shown in Figures 29A and 29B.

[0118] (Example usage) The flow through the carotid bifurcation at various stages of the method of this disclosure will be described. First, the distal sheath 605 of the arterial access device 110 (or the percutaneous sheath of any embodiment described herein) is introduced into the common carotid artery (CCA). As previously stated, entry into the common carotid artery (CCA) may be via a transcarotid or transfemoral approach and may be performed by either a direct surgical cut-down or percutaneous access. After the sheath 605 of the arterial access device 110 is introduced into the common carotid artery (CCA), blood flow continues in the anterograde direction (AG), and the flow from the common carotid artery enters both the internal carotid artery (ICA) and the external carotid artery (ECA).

[0119] Next, the venous return device 115 is inserted into a venous return site, such as the internal jugular vein (IJV) or femoral vein. The shunt 120 is used to connect to the flow path 615 of the arterial access device 110 and the flow path 915 of the venous return device 115, respectively (see Figure 1A). In this way, the shunt 120 provides a passage for retrograde blood flow from the arterial access device 110 to the venous return device 115. In another embodiment, as shown in Figure 1C, the shunt 120 is connected to an external container 130 instead of the venous return device 115.

[0120] Once all components of the system are in place and connected, blood flow through the common carotid artery (CCA) is stopped, for example, by using an expandable occlusion element of a percutaneous sheath within the common carotid artery (CCA). Alternatively, the occlusion element 129 is introduced into the distal sheath 605 of the arterial access device 110 and another second occlusion device 112, as shown in Figure 2B. The external carotid artery (ECA) may be occluded by a separate occlusion element either on the same device (arterial access device 110) or on another occlusion device.

[0121] At that point, retrograde blood flow RG begins from the external carotid artery (ECA) and internal carotid artery (ICA), passing through the sheath 605, channel 615, and shunt 120, and flowing into the venous return device 115 via channel 915. The flow control assembly 125 controls the retrograde blood flow as described above. While the retrograde blood flow is maintained, the stent delivery catheter 2110 (or other intervention device) is introduced into the sheath 605. The stent delivery catheter 2110 is introduced into the sheath 605 via 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 positioned at bifurcation B.

[0122] Optionally, if blood flow from the common carotid artery continues and the internal carotid artery remains occluded, measures may be taken to further loosen the embolus from the treatment area. For example, mechanical elements may be used to flush or remove loose or loosely attached plaque or other potential embolic debris within the stent, or a thrombolytic catheter or other fluid delivery catheter may be used to flush the area, or other procedures may be performed. For example, treatment of in-stent restenosis with a balloon, atherectomy, or the use of further stents may be performed under retrograde blood flow. In another example, the occluding balloon catheter may include a lumen or channel for flow or aspiration that opens proximal to the balloon. Without requiring additional devices, saline, a thrombolytic agent, or other fluid may be injected into the treatment site, or blood and debris may be aspirated from the treatment site. The embolus thus released flows into the external carotid artery, which is generally less affected by embolic release than the internal carotid artery. Prophylactically removing any remaining potential emboli further reduces the risk of emboli being released when blood flow to the internal carotid artery is re-established. Embolisms may also be released by retrograde blood flow, in which case they flow through shunt 120 to the venous system, to the filter within shunt 120, or to the external container 130.

[0123] After the embolus at the bifurcation is removed, the occlusion element 129 or, instead, the tourniquet 2105 may be released, thereby allowing antegrade blood flow to be re-established, as shown in Figure 14E. The sheath 605 may then be removed.

[0124] Self-closing elements may be positioned around the penetration of the common carotid artery wall at the end of the procedure, before sheath 605 is withdrawn. Typically, self-closing elements are positioned at or near the start of the procedure, but optionally, they may be positioned when the sheath is withdrawn, often so as to be released onto the wall of the common carotid artery from the distal end of the sheath. The use of self-closing elements is advantageous because it substantially influences the rapid closure of the penetration of the common carotid artery when the sheath is withdrawn. Such rapid closure can reduce or eliminate unexpected bleeding at the end of the procedure or in the event of accidental sheath dislodgement. Furthermore, such self-closing elements may reduce the risk of arterial wall dissection occurring during access. In addition, self-closing elements may be configured to apply friction or other retaining forces to the sheath during the procedure. Such retaining forces are advantageous and can reduce the likelihood of accidental sheath dislodgement during the procedure. Self-closing elements eliminate the need for vascular surgical closure of the artery by suturing after sheath removal, reduce the need for a wide surgical field, and significantly reduce the surgical skill required for the procedure.

[0125] While various embodiments of methods and devices are described in detail with reference to specific versions, it should be understood that other versions, embodiments, uses, and combinations thereof are also possible. Therefore, the intent and scope of the appended claims should not be limited to the descriptions of embodiments included herein.

Claims

1. A system used to access and treat the carotid artery, An external guide sheath configured to be delivered percutaneously into the carotid artery, An internal catheter movably disposed within the external guide sheath, wherein the internal catheter has an expandable element located in the distal region of the internal catheter, and the internal catheter has a lumen extending between a proximal end and a distal end, which is adapted to receive blood flow from the common carotid artery, the external guide sheath and the internal catheter are adapted to be introduced together into the common carotid artery, and the expandable element is adapted to dilate and occlude the common carotid artery, A locking collar positioned in the proximal region of the outer guide sheath, wherein the locking collar is configured to rotate around the outer wall of the outer guide sheath, the locking collar has a first set of threads on its inner wall, the first set of threads engages with a second set of threads on the outer wall of the inner catheter, and the locking collar rotates to engage the first set of threads with the second set of threads, thereby fixing the position of the inner catheter relative to the outer guide sheath, the locking collar comprises The aforementioned internal catheter is The outer guide sheath is movably positioned inside the outer guide sheath between a first position in which the outer guide sheath covers the expandable element and restrains it in a contracted state, and a second position in which the outer guide sheath no longer covers the expandable element and does not restrain it. A system in which, when the internal catheter is in the second position, the threads of the first set are aligned with the threads of the second set.

2. The internal catheter is further equipped with a shunt that is fluidly connected to it. The system according to claim 1, wherein the shunt provides a pathway for blood to flow from the internal catheter to the return site.

3. The system according to claim 1, wherein the expandable element is a balloon extending to the outer circumference of the outer wall of the inner catheter.

4. The system according to claim 1, wherein the internal catheter has a bent portion in the distal region of the internal catheter.

5. The system according to claim 4, wherein the expandable element is a balloon that can extend outward from a hole in the inner catheter, the hole being located at the bend.

6. The system according to claim 5, wherein the balloon is fixedly attached to the inner catheter near the bend, and the balloon can be completely contained within the inner catheter.

7. The system according to claim 5, wherein the balloon is fixedly attached to the inner catheter near the bend, the balloon can be positioned flush with the outer wall of the inner catheter, and the balloon closes the hole at the bend.

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

9. The system according to claim 5, wherein the balloon is positioned inside the inner catheter adjacent to the hole.

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

11. The system according to claim 10, wherein the delivery wire has an expansion lumen that can inflate the balloon.

12. The system according to claim 10, wherein the delivery wire can be used to move the balloon inside and outside the inner catheter through the hole.

13. The system according to claim 5, wherein the internal catheter has a main lumen and a secondary lumen, and the balloon is at least partially positioned within the secondary lumen.

14. The system according to claim 1, wherein the locking collar has an outer size that is extended with respect to at least a portion of the outer guide sheath.

15. The system according to claim 1, wherein the expandable element has a corrugated shape.

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