Methods and devices for transcarotid access

Abstract

A micropuncture kit for direct access into a surgically exposed blood vessel lumen using direct visual guidance, the kit comprising a micropuncture access needle including a proximal hub coupled to an elongated shaft defining an inner lumen and a visible depth indicator positioned on the elongated shaft a distance away from the distal end of the elongated shaft. The kit comprises: an access guidewire sized to be received through the inner lumen of the micropuncture access needle; and a microentry cannula having an elongated body defining an inner lumen and a plurality of visible depth indicators formed on the elongated body. The guidewire comprises a distal end and at least one visible depth indicator positioned on the access guidewire a distance away from the distal end of the guidewire. Each of the plurality of visible depth indicators identifies a distance from the distal end of the cannula. Related systems, devices, and methods are provided.

Description

[0001] This application is a divisional application of the invention patent application with application date of June 29, 2018, application number 201880056358.2, and invention name “Method and device for transcarotid access”.

[0002] Reference to priority documents

[0003] This application claims priority to U.S. Patent Application No. 15 / 641,966, filed on July 5, 2017, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0004] The present invention relates to a method and apparatus for transcarotid access. Background Art

[0005] The present disclosure generally relates to medical methods, systems and devices for performing intravascular interventions. More specifically, the present disclosure relates to methods and systems for directly accessing the carotid artery to perform interventional procedures in the treatment of vascular disease and other diseases associated with the vascular system.

[0006] Interventional procedures are performed to treat vascular disease, such as vascular stenosis, occlusion, aneurysm or fistula. Interventional procedures are also used to perform surgery on organs or tissue targets that are accessible via blood vessels, such as denervation or ablation of tissue to intervene in nerve conduction, vascular embolization to limit blood flow to tumors or other tissues, and delivery of drugs, contrast agents or other agents to intravascular or extravascular targets for therapeutic or diagnostic purposes. Interventional procedures are typically divided into several categories: coronary, neurovascular and peripheral vascular. Most procedures are performed in the arterial system via an arterial access site.

[0007] Methods for obtaining arterial access to perform these procedures are well established and fall into two broad categories: percutaneous access and surgical cut-down. Most interventional procedures employ percutaneous access. For this access method, a needle is inserted from the skin through the subcutaneous tissue and muscle layer to the vessel wall and into the vessel itself. Vascular ultrasound is often used to image the vessel and surrounding structures and facilitates accurate insertion of the needle into the vessel. Depending on the size of the artery and the access device, the method will be different, for example, the Seldinger technique or a modified Seldinger technique includes placing a sheath guidewire into the vessel with the aid of a needle. Typically, the sheath guidewire is 0.035" or 0.038". In some instances, a micropuncture or microentry technique is used, based on which the vessel is initially entered through a small gauge needle and then dilated through a 4F microperforated cannula through which the sheath guidewire is placed. Once the guidewire is placed, an access sheath and a sheath dilator are inserted into the artery along the guidewire. In other instances, such as where the radial artery is being used as the access site, a smaller sheath guidewire, such as a 0.018" guidewire, is used with the initial needle puncture. The dilator of the radial access sheath is designed to accommodate this smaller size guidewire so that the access sheath and dilator can be inserted into the artery along the 0.018" guidewire.

[0008] In surgical incision, a skin incision is made and the tissue is cut to the level of the target artery. This method is usually used when the operation requires a large access device, the puncture entry is risky to the blood vessel and / or there is a possibility of unreliable closure of the access site at the end of the operation. Depending on the size of the artery and the access device, an incision is formed in the vessel wall using a blade, or the vessel wall is directly punctured by an access needle, and the sheath guide wire is placed through the access needle. Micropuncture technology can also be used to place the sheath guide wire. As mentioned above, the access sheath and sheath dilator are inserted into the artery along the sheath guide wire. Once the access sheath is in place, the dilator and sheath guide wire are removed. The device can now be introduced into the artery via the access sheath and moved forward to the target site using standard interventional techniques and fluoroscopy to perform the operation.

[0009] Access to the target site is accomplished from an arterial access site that is easily accessible from the skin. Typically, this is the femoral artery, which is both relatively large and relatively shallow, and is easily closed using direct compression or one of a variety of vascular closure devices when the procedure is completed. Therefore, intravascular devices are designed specifically for this femoral artery access site. However, the femoral artery and its surroundings are sometimes pathological, making it difficult or impossible to safely enter from this site or introduce the device into the vascular system. In addition, the treatment target site may be a considerable distance from the femoral artery access point, requiring the device to be quite long and cumbersome. In addition, reaching the target site from the femoral artery access point may involve traversing tortuous and / or diseased arteries, which increases the duration and risk of the operation. For these reasons, alternative access sites are sometimes used. These alternative access sites include the radial artery, the brachial artery, and the axillary artery. However, these access sites are not always ideal because they involve smaller arteries and may also include tortuous sections, and there may also be a certain distance between the access site and the target site.

[0010] Some exemplary problems existing in the prior art

[0011] In some instances, the desired access site is the carotid artery. For example, surgery to treat disease at the carotid bifurcation and internal carotid artery is fairly close to this access site. Surgery within the intracranial and cerebral arteries is also closer to this access site than the femoral artery. This artery is also larger than some of the alternative access arteries noted above (the common carotid artery is typically 6 to 10 mm in diameter, the radial artery is 2 to 3 mm in diameter).

[0012] Since most of the access devices used in interventional surgery are designed for femoral artery access, these devices are not ideal for alternative carotid access sites in terms of length and mechanical properties. This makes the operation more cumbersome, and in some cases, if a device designed for femoral artery access is used in a carotid access operation, the risk is greater. For example, in some operations, such as in an operation involving placing a stent at the carotid bifurcation, it is desirable to keep the distal end of the access sheath below or away from the carotid bifurcation. For patients with a low bifurcation, a short neck, or a very deep carotid artery, the angle at which the sheath enters the artery (relative to the longitudinal axis of the artery) is very steep relative to the longitudinal axis of the artery, that is, it is more inclined to be vertical rather than parallel relative to the longitudinal axis of the artery. This steep angle increases the difficulty and risk of sheath insertion and device insertion through the sheath. In these operations, there is also a risk of sheath displacement because only a sheath of minimum length can be inserted. In the case of femoral or radial artery access, the sheath is typically inserted into the artery until the hub of the sheath is located, keeping the sheath very securely and parallel to the artery, thereby preventing problems with steep insertion angles and sheath displacement at the femoral or radial artery access site.

[0013] In other procedures, such as those requiring cerebral vascular access, it is desirable to position the sheath tip up to and possibly including the petrous portion of the internal carotid artery. Conventional interventional sheaths and sheath dilators are not flexible enough to be safely positioned at this site.

[0014] Furthermore, radiation exposure may be a problem for the hands of a practitioner utilizing a transcarotid access site if the working area is close to the access site. Summary of the invention

[0015] There is a need for a system of devices that optimizes ease and safety of direct arterial access to the common carotid artery. There is also a need for a system of devices that minimizes radiation exposure to the operator. There is also a need for methods for safely and easily accessing the carotid artery to perform peripheral vascular and neurovascular interventional procedures.

[0016] Methods and devices are disclosed for achieving safe, rapid and relatively short and direct transcarotid access to arterial vessels for the treatment of coronary heart disease, peripheral vascular and neurovascular diseases. The devices and related methods include transcarotid access devices, guide catheters, catheters and guidewires specifically for reaching target anatomical tissue via a transcarotid access site. Also included in the disclosure are kits of various combinations of these devices for facilitating various types of transcarotid interventional procedures.

[0017] In one aspect, a system is disclosed for accessing a device for a carotid artery via direct puncture of the carotid artery wall, comprising a sheath guidewire, an arterial access sheath, and a sheath dilator, wherein the arterial access sheath and the sheath dilator are sized and configured to be inserted directly into the common carotid artery in combination along the sheath guidewire, and wherein the sheath has an inner lumen and a proximal port so that the inner lumen provides a passage for insertion of an interventional device into the carotid artery via the proximal port.

[0018] In another aspect, a system for accessing a carotid artery further comprises an access needle, an access guidewire, and an access cannula, all sized and configured to insert a sheath guidewire through the wall of the carotid artery so that an arterial access sheath and dilator can be placed into the carotid artery percutaneously or via surgical incision.

[0019] In another aspect, a method for treating coronary artery disease, peripheral vascular or neurovascular disease is disclosed, comprising: forming a puncture in a wall of a carotid artery; positioning an arterial access sheath within the artery through the puncture; and treating a target site using a treatment device.

[0020] In another aspect, an arterial access sheath for introducing an interventional device into an artery is disclosed. The arterial access sheath includes an elongated body and an inner cavity in the elongated body, the size and shape of the elongated body being designed to be introduced into the common carotid artery via the carotid artery at an entry site in the neck, the inner cavity having a proximal opening in the proximal region of the elongated body and a distal opening in the distal region of the elongated body. The inner cavity provides a passage for introducing an interventional device into the common carotid artery when the elongated body is positioned in the common carotid artery. The elongated body has a proximal segment and a distal-most segment that is more flexible than the proximal segment. The ratio of the total length of the distal-most segment to the total length of the sheath body is one-tenth to one-half of the total length of the sheath body.

[0021] In a related aspect, a micropuncture kit for direct access into a surgically exposed vascular lumen using direct visual guidance is disclosed. The kit includes a micropuncture access needle, which includes a proximal hub coupled to an elongated shaft defining an inner cavity and a visible depth indicator positioned on the elongated shaft a distance away from the distal end of the elongated shaft. The kit includes an access guidewire sized to be received through the inner cavity of the micropuncture access needle. The guidewire includes a distal end and at least one visible depth indicator, the at least one visible depth indicator positioned on the access guidewire a distance away from the distal end of the guidewire. The kit includes a microentry cannula, which includes an elongated body defining an inner cavity and a plurality of visible depth indicators formed on the elongated body, wherein each of the plurality of visible depth indicators identifies a distance from the distal end of the cannula.

[0022] The access guidewire can include: a distal-most flexible section including a distal end of the guidewire; a transition section proximal to the distal-most flexible section; and a more rigid core section extending proximally from the transition section. The distal-most flexible section can be between 1 cm and 2 cm, and the transition section can be between 2 cm and 3 cm. The transition section and the core section can be configured to support the micro-entry cannula inserted into the blood vessel. The outer diameter of the guidewire can be in the range of 0.014" to 0.018", and the micropuncture needle can be in the range of from 21G to 24G. The at least one visible depth indicator positioned on the access guidewire can have a proximal edge, a distal edge, and a width extending between the proximal edge and the distal edge. The distance away from the distal end of the guidewire can be measured from the distal end to the distal edge of the at least one visible depth indicator. Inserting the access guidewire through the lumen of the elongated shaft until the distal edge is aligned with the rear end of the proximal hub of the access needle can cause the distal tip of the guidewire to extend beyond the distal tip extension length of the elongated shaft. Advancing the access guidewire through the lumen of the elongated shaft until the distal edge is aligned with the rear end of the proximal hub of the access needle can cause the distal tip of the guidewire to extend beyond the distal tip extension length of the elongated shaft plus the width of the at least one visible depth indicator. The extension length can be 3 cm, and the width of the at least one visible depth indicator can be 2 cm. The visible depth indicator of the access needle can be a chemical etched mark, a laser etched mark, or a silk screen mark. Each of the plurality of visible depth indicators can be formed by a plurality of marks. The plurality of marks can identify a plurality of increments from the distal tip of the cannula. Each increment can be 10 mm, and the plurality of marks can be at least one mark. A first visible depth indicator of the plurality of visible depth indicators on the cannula can include one mark, and the first visible depth indicator can be 10 mm away from the distal end of the cannula. A second visible depth indicator of the plurality of visible depth indicators on the cannula can include two marks, and the second visible depth indicator can be 20 mm away from the distal end of the cannula. A third visible depth indicator of the plurality of visible depth indicators on the cannula can include three marks, and the third visible depth indicator can be 30 mm away from the distal end of the cannula. A fourth visible depth indicator of the plurality of visible depth indicators on the cannula can include four marks, and the fourth visible depth indicator can be 40 mm away from the distal end of the cannula. A fifth visible depth indicator of the plurality of visible depth indicators on the cannula can be 50 mm away from the distal end of the cannula and can be a solid strip having a width greater than the width of one mark.The distance of the visible depth indicator of the access needle from the distal end of the elongated shaft can be between 3 mm and 7 mm. The visible depth indicator of the access needle can be a chemically etched mark, a laser etched mark, or a silk screened mark.

[0023] Other features and advantages will become apparent from the following description of various embodiments illustrating, by way of example, the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Initial transcarotid access to the system is shown.

[0025] Figure 2 The transcarotid access sheath system is shown.

[0026] Figure 3 Components of a transcarotid access system are shown being used to access the carotid artery for carotid surgery.

[0027] Figure 4 Shown is an access sheath of a transcarotid access system being used to access the internal carotid artery for intracranial or neurovascular surgery.

[0028] Figure 5 An embodiment of an arterial access sheath is shown.

[0029] Figure 6 and 7 The distal region of the artery entering the sheath is shown.

[0030] Figure 8-11E An embodiment of an arterial access sheath is shown.

[0031] Fig.12 One embodiment of a dilator is shown.

[0032] Fig.13 and 14 An enlarged view of the proximal region of the dilator is shown.

[0033] Fig.15 and 16 A two-part dilator embodiment is shown.

[0034] Fig.17 The distal region of the dilator with two guidewire lumens is shown.

[0035] Fig.18 Shows Fig.17 Cross-sectional view of the distal region of .

[0036] Fig.19A An embodiment of a transcarotid initial access system is shown.

[0037] Fig.19B Shows Fig.19A Detail of the entry needle taken at circle BB.

[0038] Fig. 20A The distal region of an embodiment of an access guidewire is shown.

[0039] Figures 20B-20C Shows Fig. 20A The entry guidewire and Fig.19A The relative expansion of the entry needle.

[0040] Fig.21A is an embodiment of a microentry cannula.

[0041] Fig. 21B yes Fig.21A Detail of the microentry cannula taken at circle BB. DETAILED DESCRIPTION

[0042] Methods, systems, and devices for accessing and treating the vascular system via a transcarotid access point in the carotid region are disclosed.

[0043] Figure 1 A first embodiment of a transcarotid initial access system 100 of a device for establishing initial access to a carotid artery to enable introduction of a guidewire into the carotid artery is shown. Access to the carotid artery occurs at an access site located in the patient's neck, such as in the area of ​​the patient's carotid artery. The device of the transcarotid initial access system 100 is particularly suitable for directly accessing the carotid artery through the wall of the common carotid artery.

[0044] like Figure 1 As shown, the transcarotid initial access system 100 includes an access needle 120, an access guidewire 140, and a micropuncture cannula 160. The access needle 120, the access guidewire 140, and the micropuncture cannula 160 are all suitable for introduction into the carotid artery via carotid puncture, as further described below. The carotid puncture can be performed, for example, percutaneously or via surgical incision. Embodiments of the initial access system 100 can be adjusted for one or another puncture method as further described below.

[0045] After establishing access to the carotid artery using the initial access system 100, an access sheath can be inserted into the carotid artery at the access site, wherein the access sheath can be part of a transcarotid access sheath system. Figure 2A first embodiment of a transcarotid access sheath system 200 of a device for inserting an access sheath into a carotid artery along a sheath guidewire is shown. When inserted into the carotid artery, the access sheath enables or allows at least one interventional device to be introduced into the carotid artery via the inner lumen of the access sheath for the purpose of performing an interventional procedure on a region of the vascular system. The transcarotid access sheath system 200 includes an access sheath 220, a sheath dilator 260, and a sheath guidewire 300. The access sheath 220, the sheath dilator 260, and the sheath guidewire 300 are all suitable for introduction into the carotid artery via a carotid puncture, as further described below. The carotid puncture can be performed percutaneously or via a surgical incision. Embodiments of the system 200 can be adjusted toward one or another puncture method as further described below.

[0046] In one embodiment, some or all of the components of the transcarotid initial access system 100 and the transcarotid access sheath system 200 can be combined into a transcarotid access system kit, such as by combining the components into a single packaging container or a batch of containers bundled together.

[0047] Figure 3 An access sheath 220 is shown being used to access a common carotid artery 310 for carotid stenting. The access sheath 220 is inserted into the common carotid artery 310 via a lower surgical incision 315. As further described below, the access sheath 220 has a lumen with openings at the proximal and distal ends or regions of the access sheath 220. With the distal portion of the access sheath 220 within the carotid artery and the proximal portion outside the patient's body, the lumen provides a pathway for inserting an interventional device into the artery.

[0048] Figure 4 The access sheath 200 of the transcarotid access system is shown being used to access the internal carotid artery 405 for intracranial or neurovascular surgery. The arterial access sheath 200 is inserted into the common carotid artery 310 via percutaneous puncture. Once inserted into the common carotid artery 310, the distal tip of the access sheath 220 is advanced into the internal carotid artery ICA 320 and upward toward the distal cervical or petrous ICA 405 (relative to the distal cervical or petrous ICA 405). Figure 4 The perforation in the distal cervical or petrous ICA 405 is displaced anteriorly or beyond the distal cervical or petrous ICA 405.

[0049] Figure 3 and 4 Both show that the arterial access sheath 220 is being advanced upward through the patient's neck toward the patient's brain. In another embodiment, the arterial access sheath 220 can be advanced downward (relative to the patient's heart) toward the patient's heart (such as toward, for example, the aorta). Figure 3-4U.S. Patent No. 8,545,552, entitled “Systems and Methods for Transcatheter Aortic Valve Treatment,” which is incorporated herein by reference, describes an exemplary method of inserting an access sheath directly into the carotid artery and advancing the interventional device toward the aorta and ultimately toward the aortic valve.

[0050] Arterial access sheath

[0051] Refer to Figure 2 , an embodiment of the transcarotid access sheath 220 includes an elongated sheath body 222 and a proximal adapter 224 at the proximal end of the elongated sheath body 222 of the access sheath 220. The elongated sheath body 222 is the portion of the arterial access sheath 220 that is sized and shaped to be inserted into an artery, and wherein at least a portion of the elongated sheath body is actually inserted into the artery during surgery. The proximal adapter 224 includes a hemostatic valve 226 and an elongated flushing line 228 having an inner lumen that communicates with the inner lumen of the sheath body 222. The proximal adapter 224 may have a larger diameter or cross-sectional size than the sheath body 222. The hemostatic valve 226 is in communication with the inner lumen of the sheath body 222 to allow a device to be introduced therein while preventing or minimizing blood loss through the inner lumen during surgery. In one embodiment, the hemostatic valve 226 is a static sealing type passive valve. In an alternative embodiment of the arterial access sheath 220 (in Figure 5 ), the hemostasis valve 226 is an adjustable opening valve such as a Tuohy-Borst valve 227 or a rotary hemostasis valve (RHV). Alternatively, the access sheath 220 may terminate on the proximal end in a female Luer adapter, and a separate hemostasis valve member may be attached to the female Luer adapter, which may be a passive sealing valve, a Tuohy-Borst valve, or a rotary hemostasis valve (RHV).

[0052] The elongated sheath body 222 of the arterial access sheath 220 has a diameter suitable for or specifically optimized to provide arterial access to the carotid artery. In one embodiment, the elongated sheath body 222 is in the size range of 5 to 9 Fr, or alternatively in the inner diameter range of 0.072 inches to 0.126 inches. In one embodiment, the elongated sheath body 222 is a 6 or 7 Fr sheath. In one embodiment where the sheath is also used for pumping or reverse flow or for introducing a larger device, the sheath is an 8 Fr sheath.

[0053] The elongated sheath body 222 of the arterial access sheath 220 has a length from the proximal adapter 224 to the distal end of the elongated sheath body 222, which is suitable for reaching the treatment site located in the brain or relative to the arterial access site in the common carotid artery CCA (common carotid artery) toward the brain. For example, in order to enter the carotid bifurcation or the proximal internal carotid artery ICA from the CCA access site, the elongated sheath body 222 of the access sheath 220 (i.e., the part that can be inserted into the artery) can have a length in the range of 7 to 15 cm. In one embodiment, the elongated sheath body 222 has a length in the range of 10-12 cm. In order to enter the same target site from the femoral artery access site, a typical access sheath must be between 80 cm and 110 cm, or a guide catheter must be inserted through the arterial access sheath and moved forward to the target site. The guide catheter passing through the access sheath occupies the lumen area and thus constrains the size of the device that can be introduced into the target site. Therefore, relative to the access sheath that requires the use of a guide catheter to allow the interventional device to reach the target site, the access sheath that allows the interventional device to reach the target site without a guide catheter has an advantage.

[0054] Alternatively, to position the distal tip of the elongated sheath body 222 more distally relative to the access site, for example, to perform intracranial or neurovascular surgery from the CCA access site, the elongated sheath body 222 of the access sheath 220 may have a length in the range of 10 cm to 30 cm, depending on the desired target location of the distal tip of the sheath. For example, if the target location is the distal CCA or the proximal ICA, the elongated sheath body 222 may be in the range of 10 cm to 15 cm. If the desired target location is the mid-to-distal cervical, petrous, or cavernous segment of the ICA, the elongated sheath body 222 may be in the range of 15 to 30 cm.

[0055] Alternatively, the arterial access sheath 220 is configured or adapted for a treatment site or target location that is proximal to the arterial access site (i.e., toward the aorta) when the access site is within the common carotid artery. For example, the treatment site can be a proximal region of the CCA, CCA orifice, ascending or descending aorta or aortic arch, aortic valve, coronary arteries, or other peripheral arteries. For these target locations, the appropriate length of the elongated sheath body 222 depends on the distance from the target site to the access site. In this configuration, the elongated sheath body 222 is placed through the arterial access site and oriented toward the lower aorta.

[0056] The access sheath 220 may also include a radiopaque end marker 230. In one example, the radiopaque end marker is a metal band embedded near the distal end of the sheath body 222 of the access sheath 220, such as a platinum-iridium alloy. Alternatively, the access sheath end material may be a separate radiopaque material, such as a barium polymer or a tungsten polymer mixture. The sheath end itself is configured so that when the access sheath 220 is assembled using a sheath dilator 260 to form a sheath assembly, the sheath assembly can be smoothly inserted along the sheath guidewire 300 through the arterial perforation with minimal resistance. In one embodiment, the elongated sheath body 222 of the access sheath 220 has a smooth or hydrophilic coating to reduce friction during insertion into the artery. In one embodiment, the distal coating is limited to 0.5 to 3 cm at the farthest point of the elongated sheath body 222, so that it is conducive to insertion without sacrificing the safety of the sheath at the perforation site or the ability of the operator to firmly hold the sheath during insertion. In an alternative embodiment, the sheath is not coated.

[0057] refer to Figure 2 In one embodiment, the arterial access sheath 220 has features that help secure the sheath during surgery. For example, the access sheath 220 may have suture eyelets 234 or one or more ribs 236 molded into or otherwise attached to the adapter 224 (located at the proximal end of the elongated sheath body 222) that allow the operator to suture the sheath hub to the patient.

[0058] For a sheath suitable for insertion into the common carotid artery to access the carotid bifurcation, the length of the elongated sheath body 222 may be in the range of 7 to 15 cm (typically 10 to 12 cm). The inner diameter is typically in the range of 5 Fr (1 Fr = 0.33 mm) to 10 Fr (typically 6 to 8 Fr). For a sheath suitable for insertion into the middle or distal internal carotid artery via the common carotid artery to access the intracranial or cerebral vessels, the length of the elongated sheath body 222 may be in the range of 10 to 30 cm (typically 15 to 25 cm). The inner diameter is typically in the range of 5 Fr (1 Fr = 0.33 mm) to 10 Fr (typically 5 to 6 Fr).

[0059] Particularly when the sheath is introduced above the clavicle but below the carotid bifurcation by transcarotid artery, it is desirable that the elongated sheath body 222 is flexible while maintaining a hoop strength that resists twisting or buckling. This is particularly important in surgeries where the amount of sheath insertion into the artery is limited and there is a steep insertion angle as in transcarotid artery access in patients with deep carotid arteries and / or short necks. In these instances, there is a tendency for the end of the sheath body to be oriented toward the rear wall of the artery due to the rigidity of the sheath. This causes the risk of injury due to the insertion of the sheath body itself or a device (such as a guidewire) inserted into the artery through the sheath. Alternatively, the distal region of the sheath body may be placed in a distal carotid artery including one or more bends, such as the rocky ICA. Therefore, it is desirable that the sheath body 222 be configured so that it can bend when inserted into the artery without twisting. In one embodiment, the sheath body 222 is circumferentially reinforced (such as by a stainless steel or nitinol braid, a spiral ribbon, a spiral wire, a cut stainless steel or nitinol hypotube, a cut rigid polymer, etc. and an inner liner) so that the reinforcement structure is sandwiched between the outer shell layer and the inner liner. The inner liner can be a low friction material such as PTFE. The outer shell can be one or more of a group of materials including Pebax, thermoplastic polyurethane, or nylon.

[0060] In one embodiment, the flexibility of the sheath body 222 can vary along its length. This change in flexibility can be achieved in various ways. For example, the hardness and / or material of the outer shell can vary in various sections. Alternatively, the reinforcing structure or material can vary along the length of the sheath body. In one embodiment, the distal-most section of the sheath body 222 is more flexible than the rest of the sheath body. For example, the bending stiffness of the distal-most section is one-third to one-tenth of the bending stiffness of the rest of the sheath body 222. In one embodiment, the distal-most section has a bending stiffness of 50 to 300 N-mm 2 The bending stiffness (E*I) of the sheath body 222 is within the range of 500 to 1500 N-mm 2 , where E is the elastic modulus and I is the area moment of inertia of the device. For a sheath configured for use in a CCA access site, the flexible distal-most segment comprises a significant portion of the sheath body 222 that can be expressed as a ratio. In one embodiment, the ratio of the length of the flexible distal-most segment to the total length of the sheath body 222 is at least one-tenth and at most one-half of the length of the entire sheath body 222.

[0061] In some examples, the arterial access sheath is configured to enter the carotid bifurcation or the proximal internal carotid artery ICA from the CCA access site. In this example, an embodiment of the sheath body 222 has a distal-most section 223 of 3 to 4 cm and the entire sheath body 222 is 10 to 12 cm. In this embodiment, the ratio of the length of the flexible distal-most section to the total length of the sheath body 222 is about one-quarter to one-half of the total length of the sheath body 222. In another embodiment, there is a transition section 225 between the distal-most flexible section and the proximal section 231, wherein there are one or more sections with different flexibility between the distal-most section and the rest of the sheath housing. In this embodiment, the distal-most section is 2 to 4 cm, the transition section is 1 to 2 cm, and the entire sheath body 222 is 10 to 12 cm, or expressed as a ratio, the distal-most flexible section and the transition section together form at least one-quarter and at most one-half of the total length of the sheath body.

[0062] In some instances, the sheath body 222 of the arterial access sheath is configured to be inserted into the internal carotid artery more distally relative to the arterial access position, and may be inserted into the intracranial section of the internal carotid artery. For example, the most distal section 223 of the elongated sheath body 222 is 2.5 to 5 cm and the length of the entire sheath body 222 is 20 to 30 cm. In this embodiment, the ratio of the length of the most distal section of the flexibility to the total length of the sheath body is one-tenth to one-quarter of the entire sheath body 222. In another embodiment, there is a transition section 225 between the most distal flexible section and the proximal section 231, wherein the most distal section is 2.5 to 5 cm, the transition section is 2 to 10 cm, and the entire sheath body 222 is 20 to 30 cm. In this embodiment, the most distal flexible section and the transition section together form at least one-sixth and at most one-half of the entire length of the sheath body.

[0063] Other embodiments are adapted to reduce, minimize or eliminate the risk of damage to the artery due to the distal-most sheath tip facing and contacting the posterior arterial wall. In some embodiments, the sheath has a structure configured to center the lumen of the artery with the sheath body distally disposed so that the longitudinal axis of the distal region of the sheath body is substantially parallel to the longitudinal axis or central axis of the lumen of the vessel. Figure 6 In the illustrated embodiment, the sheath alignment feature is an inflatable or expandable bumper, such as a balloon 608, located on the outer wall of the arterial access sheath 220. The balloon 608 can expand in size to exert a force on the inside of the artery that contacts and pushes the elongated body 222 of the arterial access sheath away from the arterial wall.

[0064] In another embodiment, the sheath alignment feature is one or more mechanical structures on the sheath body that can be actuated to extend outward from the sheath tip. In one embodiment, the sheath body 222 is configured to be inserted into an artery so that a specific edge of the artery entering abuts the posterior wall of the artery. In this embodiment, the sheath alignment feature only needs to extend outward in one direction relative to the longitudinal axis of the sheath body 222 to lift or push the sheath tip away from the posterior wall of the artery. For example, Figure 6 As shown, the inflatable buffer 608 is a blister on one side of the sheath body. In another example, the mechanical feature extends only on one side of the sheath body.

[0065] In another embodiment, at least a portion of the sheath body 222 is pre-formed so that after the sheath is inserted, the end is more aligned with the longitudinal axis of the vessel, even if the sheath insertion angle is steep. In this embodiment, when the dilator is assembled with the sheath during insertion of the sheath over the sheath guidewire, the sheath body is generally straight, but once the dilator and guidewire are removed, the most distal segment of the sheath body is in a curved or angled shape. In one embodiment, the sheath body is formed so that when measured from the main axis of the sheath body, the most distal 0.5 to 1 cm segment is at an angle of 10 to 30 degrees, with a radius of curvature of approximately 0.5". In order to maintain the curved or angled shape of the sheath body after it has been straightened during insertion, the sheath can be heat set in an angled or curved shape during manufacturing. Alternatively, the reinforcement structure can be constructed of nitinol and heat formed into a curved or angled shape during manufacturing. Alternatively, additional spring elements can be added to the sheath body, such as adding strips of spring steel or nitinol of appropriate shape to the reinforcement layer of the sheath.

[0066] In an alternative embodiment, there are methods where it is desirable to minimize flow resistance through an access sheath, such as described in US Pat. No. 7,998,104 to Chang and US Pat. No. 8,157,760 to Criado, both of which are incorporated herein by reference. Figure 7This embodiment of the sheath body 222 is shown, wherein the sheath body has a stepped or tapered configuration with a distal region 705 of reduced diameter (wherein the reduced diameter is relative to the rest of the sheath). The size of the distal region 705 of the stepped sheath can be designed for insertion into the carotid artery, typically having an inner diameter in the range of 0.065 inches to 0.115 inches, and the remaining proximal regions of the sheath have a larger outer diameter and lumen diameter, wherein the inner diameter is typically in the range of 0.110 inches to 0.135 inches. The larger lumen diameter of the rest of the sheath body minimizes the flow resistance through the sheath. In one embodiment, the distal segment 705 of reduced diameter has a length of about 2cm to 4cm. The relatively short length of the distal segment 705 of reduced diameter allows this segment to be positioned in the common carotid artery CCA via a transcarotid artery approach to reduce the risk that the distal end of the sheath body will contact the bifurcation B. Moreover, the segment of reduced diameter also allows the size of the arteriotomy used to introduce the sheath into the artery to be minimized while the level of flow resistance is minimal. Further, the reduced diameter distal section may be more flexible and, therefore, may better conform to the lumen of a blood vessel.

[0067] In some instances, such as in surgeries where distal emboli may form, it may be desirable for the sheath body 222 to also occlude the artery in which it is positioned. In these cases, occluding the artery stops antegrade blood flow within the artery and thereby reduces the risk of distal emboli that may cause neurological symptoms such as TIA or stroke. Figure 8 An embodiment of an arterial access sheath 220 is shown with an inflatable balloon 805 on the distal region, which is inflated via an inflation line 810 that connects the internal inflation lumen in the sheath body 222 to the stopcock 229, which in turn can be connected to an inflation device. In this embodiment, there is also a Y-arm 815 that can be connected to a passive or active pumping source to further reduce the risk of distal emboli.

[0068] In some instances, it may be desirable to move the hemostasis valve away from the distal end of the sheath while maintaining the length of the sheath that is insertable into the sheath body 222. This embodiment is configured to move the operator's hand (and indeed his or her entire body) away from the target site, and therefore away from the image intensifier used to fluorescently image the target site, thereby reducing radiation exposure to the user during surgery. In essence, this extends the portion of the arterial access sheath 220 outside the body. The inner and outer diameters of this portion can be larger than the sheath body 222. In instances where the outer diameter of the catheter inserted into the sheath approaches the inner diameter of the sheath body, the annular space available for flow in the lumen is limited. Minimizing the sheath body length therefore helps minimize this flow resistance (such as during flushing of the sheath with saline or contrast solution or during pumping or backflow out of the sheath). In one embodiment, as Fig. 9As shown, the arterial access sheath 220 has an insertable elongated sheath body 222 (i.e., a portion configured to be inserted into an artery) and a proximal extension 905. In one embodiment, the sheath body 222 has an inner diameter of approximately 0.087" and an outer diameter of approximately 0.104", corresponding to a 6Fr sheath size, and the proximal extension has an inner diameter of approximately 0.100" to 0.125", and an outer diameter of approximately 0.150" to 0.175". In another embodiment, the sheath body 222 has an inner diameter of approximately 0.113" and an outer diameter of approximately 0.136", corresponding to an 8Fr sheath size, and the proximal extension has an inner diameter of approximately 0.125" and an outer diameter of approximately 0.175". In yet another embodiment, the sheath body 222 is stepped, having a smaller diameter distal section 705 to further alleviate flow restriction, such as Figure 7 As shown. In one embodiment, the length of the proximal extension 905 is suitable for significantly reducing the radiation exposure of the user during the transcarotid access procedure. For example, the proximal extension 905 is between 10 and 25 cm, or between 15 and 20 cm. Alternatively, the proximal extension 905 has a length that is configured to provide a distance between about 30 cm and 60 cm between the hemostatic valve 226 and the distal end of the sheath body depending on the insertable length of the access sheath. The connector structure 915 can connect the elongated sheath body 222 to the proximal extension 905. In this embodiment, the connector structure 915 may include suture eyelets 920 and / or ribs 925 to help secure the access sheath to the patient. In one embodiment, the hemostatic valve 226 is a static sealing passive valve. In an alternative embodiment, the hemostatic valve 226 is an adjustable opening valve such as a Tuohy-Borst valve 227 or a rotary hemostatic valve (RHV). Alternatively, the proximal extension may terminate at a proximal end in a female Luer adapter, and a separate hemostasis valve member may be attached to the female Luer adapter, which may be a passive sealing valve, a Tuohy-Borst valve, or a rotary hemostasis valve (RHV).

[0069] Typically, a vessel closure device requires an arterial access sheath with a maximum distance between the distal end of the sheath body and the proximal structure of the hemostatic valve of about 15 cm, where the sheath body 222 is about 11 cm and the remaining 4 cm contains the length of the proximal hemostatic valve; therefore, if the access sheath has a distance greater than 15 cm, it is desirable to remove the proximal extension 905 at the end of the procedure. In one embodiment, the proximal extension 905 can be removed in such a way that hemostasis is maintained after removal. For example, the hemostatic valve is built into the connector 915 between the sheath body 222 and the proximal extension 905. The hemostatic valve opens when the proximal extension 905 is attached to allow fluid communication and insertion of the device, but blocks blood from flowing out of the sheath when the proximal extension 905 is removed. After the procedure is completed, the proximal extension 905 can be removed, thereby reducing the distance between the proximal aspect of the hemostatic valve and the sheath end from greater than 15 cm to equal to or less than 15 cm, and thus allowing the vessel closure device to be used with the access sheath 220 to close the access site.

[0070] In some procedures, it may be desirable to connect a low resistance (large bore) flow line or shunt to the access sheath, such as described in US Pat. Nos. 7,998,104 to Chang and 8,157,760 to Criado, both of which are incorporated herein by reference. Fig.10 The arterial sheath embodiment shown has a flow circuit 1005 with an inner cavity of a Y-shaped arm 1015 leading to a connector 915. This flow circuit has an inner cavity connected to the inner cavity fluid in the sheath body. The flow circuit 1005 can be connected to a low-pressure return site such as a venous return site or a reservoir. The flow circuit 1005 can also be connected to a pumping source such as a pump or a syringe. In one embodiment, an occluding element, such as an occluding balloon, can also be included on the far end of the sheath body 222. This may be desirable in percutaneous surgery where a vascular surgical device such as a vascular hoop or a vascular clamp cannot be used to occlude a blood vessel.

[0071] In some procedures, it may be desirable to limit the amount of sheath body inserted into the artery, such as in procedures where the target area is very close to the arterial access site. For example, in stenting of the carotid bifurcation, the sheath tip should be proximal to the treatment site (relative to the access site) so that it does not interfere with stent deployment or access to the diseased area and may cause emboli to be shaken loose. Fig.11A and 11B In one embodiment of the arterial sheath 220 shown, the sheath stop 1105 is slidably connected or mounted on the outside of the distal portion of the sheath body (see also Fig. 11C and 11D). The sheath stop 1105 is shorter than the distal portion of the sheath, thereby effectively shortening the insertable portion of the sheath body 222 by forming a front stop at a certain length along the sheath body 222. The sheath stop 1105 can be a tube that, when positioned on the sheath body 222, allows the length of the distal portion of the sheath body to be exposed to slidably fit on the sheath body 222. The length can be in the range of 2 to 4 cm. More specifically, the length is 2.5 cm. The distal end of the sheath stop 1105 can be angled and oriented so that the angle is flush with the blood vessel when the sheath is inserted into the artery and acts as a stop against the arterial wall, such as when the sheath is inserted into the blood vessel. Fig.11A Alternatively, the distal end of the sheath stopper may be formed as an angled flange 1115 that contacts the arterial wall, such as Fig. 11B , 11C 11D. Flange 1115 is rounded or has an atraumatic shape to form a more reliable and atraumatic stop against the arterial wall. Sheath stop 1105 can be permanently fixed to the arterial sheath, for example, the proximal end of the sheath stop can be attached to the connector 915 of the arterial access sheath. Alternatively, sheath stop 1105 can be removed from the arterial access sheath 220 by the user, so it can be optionally utilized during surgery. In this example, sheath stop 1105 can have a locking feature structure 1110 on the proximal portion that engages with a corresponding locking feature structure on connector 915, such as a groove or recess on the proximal sheath stop that engages with a protrusion on the connector. Other locking features can also be utilized.

[0072] Refer to Figures 11C-11D, the sheath stop 1105 can include one or more cutouts, notches or recessed grooves 1120a or other features along the length of the sheath stop 1105 (e.g., along the front surface of the sheath stop 1105). The grooves 1120a can be sized to receive sutures used to secure the sheath 220 to the patient to improve sheath stability and reduce sheath displacement. The one or more recessed grooves 1120a on the sheath stop 1105 can extend along an arc around the longitudinal axis of the sheath stop 1105. The one or more recessed grooves 1120a on the front surface can alternate or be in a staggered pattern with the corresponding one or more recessed grooves 1120b on the rear surface of the sheath stop 1105 to provide additional flexibility in the front-to-rear plane for the sheath assembly while maintaining axial strength to allow the forward force of the sheath stop against the arterial wall. The enhanced flexibility of the sheath assembly can reduce the amount of pressure that may be placed on the blood vessel. In some embodiments, a visual indicator 1125 can be positioned on the front surface of the sheath stop 1105. The visual indicator 1125 can be silk screen text, lines, or other patterns. The visual indicator 1125 can be molded directly into the body of the sheath stop 1105. The indicator 1125 can provide an external visual reference for the rotational orientation of the sheath stop relative to the blood vessel (and thereby the orientation of the distal flange 1115 relative to the blood vessel). In use, the indicator 1125 can face forward relative to the patient. By using this orientation, the distal flange 1115 can be generally flat against the anterior wall of the blood vessel (e.g., the common carotid artery). Additional features that the sheath stop 1105 can include are described in U.S. Publication No. 2016 / 0296690, which is incorporated herein by reference.

[0073] As described above, the access sheath 220 can include a radiopaque end marker 230. The access sheath 220 can also include one or more markers 265 positioned on the sheath body 222 (see Fig.11E ), which provides external visual guidance during insertion of the sheath 220 without the need for special imaging to assess the insertion depth, as described in more detail below. In some embodiments, the marking 265 can be a silk screen marking that indicates the insertion depth in increments of 1 cm up to about 5 cm. The external visual reference marking 265 on the sheath body 222 can supplement the radiopaque end marking 230 and the physical depth limit provided by the sheath stop 1105. The external visual reference marking 265 can be useful, for example, when the user wants to insert the sheath 220 to a shallower depth than specified by the sheath stop 1105 or when the user removes the sheath stop 1105 from the sheath body 222.

[0074] In conditions where insertion of the sheath body is limited to between 2 and 3 cm, and particularly when the sheath body is inserted at a steep angle, the sheath may conform to a bayonet shape when secured to the patient. For example, the bayonet shape may include a first portion extending along a first axis and a second portion extending along a second axis axially offset from the first axis and / or not parallel to the first axis. The elasticity of the sheath body causes this shape to apply force to the vessel at the insertion site and increase the tendency of the sheath to dislodge from the vessel if it is not properly secured. In order to reduce stress on the vessel, the sheath stop may be pre-formed into a curved or bayonet shape so that stress of the sheath body when bent is applied to the sheath stop rather than the vessel. The sheath stop may be made of a resilient but bendable material or include a spring element such as a stainless steel or nitinol wire or strip so that when the dilator is inserted into the sheath and sheath stop assembly, the sheath is relatively straight, but when the dilator is removed, the sheath stop is in a pre-curved shape to reduce the force applied by the sheath to the vessel wall. Alternatively, the sheath stop may be made of a malleable material or include a malleable element such as a bendable wire or ribbon so that it can be formed into a desired curvature after sheath insertion to again reduce the stress imparted by the sheath to the vessel wall.

[0075] Sheath Dilator

[0076] Refer to Figure 2 , the sheath dilator 260 is a component of the transcarotid access sheath system 200. The sheath dilator 260 is an elongated body that is inserted into the artery and enables the access sheath 220 to be smoothly inserted along the sheath guidewire 300 through the puncture site in the arterial wall. Therefore, the distal end of the dilator 260 is generally tapered to allow the dilator to be inserted into the artery along the sheath guidewire 300 and to expand the needle puncture site to a larger diameter for insertion of the access sheath 220 itself. To accommodate these functions, the dilator 260 has a tapered end 268 with a taper, which is a total angle of generally between 6 degrees and 12 degrees (relative to the longitudinal axis of the dilator), which has a rounded leading edge. The sheath dilator is typically locked to the access sheath when assembled for insertion into the artery. For example, the proximal hub 264 of the sheath dilator 260 is configured to snap into or on a corresponding structure on the hemostatic valve 226 of the arterial access sheath 220. The lumen of the dilator 260 accommodates the sheath guidewire 300 with an inner diameter between 0.037" and 0.041", depending on, for example, the sheath guidewire size.

[0077] For the transcarotid access sheath system 200, it may be desirable to make the distal section of the sheath dilator 260 more flexible to correspond to the increased flexibility section of the access sheath 220. For example, the distal 2 to 5 cm of the sheath dilator 260 may be 20% to 50% more flexible than the proximal portion of the sheath dilator 260. This embodiment would allow the inserted sheath and dilator to accommodate steep insertion angles, as is the case in transcarotid access procedures, enabling smoother insertion over the guidewire while still maintaining the columnar support of the dilator. The columnar support is expected to provide the insertion force required to dilate the puncture site and insert the access sheath.

[0078] For some transcarotid access sheath systems, it may be desirable to also use a smaller diameter access guidewire (e.g., a diameter in the range of 0.014" to 0.018") to introduce the sheath and dilator into the artery. In this embodiment, the sheath dilator tapered end 268 is configured to provide a smooth transition from the smaller guidewire size to the access sheath. In one variation, the sheath guidewire is 0.018" and the dilator lumen is in the range of 0.020" to 0.022". In another variation, the sheath guidewire is 0.014" and the dilator lumen is in the range of 0.016" to 0.018". The taper is similarly modified, such as being longer in length to accommodate the taper from the smaller diameter to the inner diameter of the access sheath, or may include two taper angles to provide a smooth transition from the smaller diameter guidewire to the access sheath without excessively extending the overall length of the taper.

[0079] In some operations, it is desirable to position the distal end of the sheath body 222 of the arterial access sheath 220 in the middle to distal vertebral segment, petrous segment or cavernous segment of the ICA as described above. These segments have a curvature generally greater than 90 degrees. It may be desirable that the sheath dilator has a softer and longer taper so that these bends can be easily guided without the risk of damaging the artery. However, in order to insert the sheath through arterial puncture, the dilator desirably has a certain rigidity and taper to provide expansion force. In one embodiment, the arterial access sheath system 200 is provided or included in a kit including two or more tapered dilators 260A and 260B. The first tapered dilator 260A is used together with the arterial access device to enter the artery, and is therefore designed in a similar manner to the standard introducer sheath dilator. The exemplary material that can be used for the tapered dilator includes, for example, high-density polyethylene, 72D Pebax, 90D Pebax or a material that is comparable in rigidity and smoothness. A second tapered dilator 260B of the kit may be provided with the arterial access device, having a softer distal section or a distal section with lower bending stiffness than the distal section of the first tapered dilator. That is, the second dilator has a distal region that is softer, more flexible, or more easily articulated or bent than the corresponding distal region of the first dilator. The distal region of the second dilator is therefore easier to bend than the corresponding distal region of the first dilator. In one embodiment, the distal section of the first dilator 260A has a bending stiffness of 50 to 100 N-mm 2 The bending stiffness of the distal section of the second dilator 260B is within the range of 5 to 15 N-mm 2 flexural stiffness within the range of.

[0080] A second dilator 260B (which has a distal section with lower bending stiffness) can be exchanged with the initial first dilator so that the arterial access device can be inserted into the internal carotid artery and around the bend in the artery without causing unnecessary force or trauma to the vessel due to the softer distal section of the second dilator. The distal section of the softer second dilator can be, for example, 35 or 40D Pebax, with the proximal portion made of, for example, 72D Pebax. One or more intermediate mid-sections may be included on the second dilator to provide a smooth transition between the softer distal section and the harder proximal section. In one embodiment, one or both dilators may have a radiopaque end marker so that the position of the dilator end is visible during fluoroscopy. In one variation, the radiopaque marker is a section made of tungsten loaded with Pebax or polyurethane that is heat welded to the distal end of the dilator. Other radiopaque materials can be similarly used to form a radiopaque marker at the distal end.

[0081] To facilitate exchange of a first dilator for a second dilator, one or both dilators may be configured such that the distal section of the dilator is comprised of a tapered single lumen tube, but the proximal portion of the dilator and any adapter on the proximal end have side openings. Fig.12 An example of a dilator 1205 formed of an elongated member and a proximal hub 1210 that is sized and shaped to be inserted into an artery is shown. The dilator has a side opening 1215, such as a slot, extending along at least a portion of the length of the dilator 1205 (such as along the elongated body and the proximal hub 1210). In one embodiment, the side opening 1215 is located only on the proximal region of the dilator 1205 and passes through the proximal hub 1210, although this can vary. The side opening 1215 provides access to the lumen of the dilator 1205, such as inserting a guide wire into the lumen and / or removing the guide wire from the lumen. An annular, removable sleeve 1220 with a slot on one side is located at or near the proximal hub 1210 of the dilator 1205. The sleeve 1220 can be moved around the longitudinal axis of the hub 1210 (such as via rotation), as described below. It should be noted that the distal end of the dilator 1205 has a tapered configuration for dilating tissue.

[0082] Fig.13 An enlarged view of the proximal region of the dilator 1205 is shown. As described above, the dilator 1205 has a side opening 1215, which is in the form of a groove extending along the length of the dilator 1205 and the proximal hub 1210. The sleeve 1220 is located around the periphery of the dilator and is formed so that it covers at least a portion of the side opening 1215. Thus, the sleeve 1220 can prevent a guidewire located inside the dilator 1205 from exiting the dilator through the side opening 1215. As described above, the sleeve 1220 can rotate relative to the dilator 1205 and the proximal hub 1210. In the illustrated embodiment, the sleeve 1220 can rotate about the longitudinal axis of the dilator 1205, but other types of relative movement are also within the scope of the present disclosure. Fig.14 As shown, sleeve 1220 has a slot 1225 that can be aligned with side opening 1215. When so aligned, slot 1225 and side opening 1215 together provide an opening for a guidewire to be inserted into or removed from the lumen of dilator 1205. Sleeve 1220 can be Fig.13 The position shown (in which the sleeve covers the side opening 1215) is similar to Fig.14 12. The side opening 1215 is rotated between the positions shown (in which the side opening is exposed due to the alignment of the slot 1225 with the side opening 1215).

[0083] A method of using this embodiment of the access sheath kit is now described. A sheath guidewire (such as a 0.035" guidewire) is inserted into the common carotid artery using a modified Seldinger technique or a micropuncture technique. The distal end of the guidewire can be positioned within the internal carotid artery or the external carotid artery, or stopped within the common carotid artery without a bifurcation. An arterial access sheath with a first, stiffer dilator is inserted into the artery along the 0.035" guidewire. The arterial access sheath is inserted so that at least 2.5 cm of the sheath body 222 is located within the artery. If additional gains are desired, the arterial access sheath can be further guided and entered into the internal carotid artery. The first dilator is removed while maintaining the arterial access sheath and 0.035" guidewire in place. The side opening 1215 in the proximal portion of the dilator allows the dilator to be removed in a "quick exchange" manner so that the majority of the guidewire outside the access device can be directly grasped during dilator removal. The second dilator is then loaded onto the 0.035" guidewire and inserted into the sheath. Again, a dilator with side openings 1215 in the proximal portion of the dilator can be used to allow a 0.035" guidewire to be directly grasped during guidewire insertion in a "rapid exchange" technique. Once the second dilator is fully inserted into the arterial access device, the arterial access sheath with the second, softer-tipped dilator is advanced within the internal carotid artery and around the bends within the artery without causing unnecessary force or concern for causing vascular trauma. This configuration allows the arterial access sheath to be placed more distally without sacrificing the ability of the device to be inserted into the artery.

[0084] Alternatively, one or more standard dilators may be used without side openings. If a standard dilator without side openings is used, after the access device is inserted into the artery along the guidewire using the first dilator, the first dilator may be removed along with the guidewire, leaving only the access device in place. The second dilator may be inserted into the arterial access device along with the guidewire preloaded into the central lumen. Once fully inserted, the access device and the second dilator with a softer tip may be advanced distally in the internal carotid artery as described above. In this alternative method, the initial guidewire may be used with both dilators, or may be interchanged with a guidewire with a softer tip when inserted with a second dilator with a softer tip.

[0085] In some instances, it may be desirable to insert an access sheath system into the carotid artery over a 0.035" guidewire, but then replace the guidewire with a smaller guidewire in the range of 0.014" to 0.018". Because a steep entry angle may be required to enter the carotid artery, it may be desirable to have a guidewire that provides good support (such as a 0.035" guidewire) to first introduce the access sheath into the CCA. However, once the sheath is in the artery but the user wants to advance it further over the smaller guidewire, it may be desirable to replace the 0.035" guidewire with a smaller guidewire. Alternatively, the user may replace both the dilator and the 0.035" guidewire with a softer dilator and a smaller guidewire in the range of 0.014" to 0.018". Alternatively, the user may wish to position a 0.14" guidewire that he or she will subsequently use to introduce the interventional device while the sheath and dilator are still in place. The dilator can provide access and support for the guidewire and, in instances of critical sheath entry angles, can assist in guiding the guidewire away from the posterior wall of the artery so that the guidewire can be safely advanced into the vessel lumen without risk of luminal damage.

[0086] In such Fig.15 In the illustrated embodiment, the sheath dilator 260 is a two-part dilator assembly having an inner dilator 269 and an outer dilator 270 that are slidably attached to each other in a coaxial arrangement. The two dilators have proximal hubs 264a and 264b. When the two dilators are assembled together, the two hubs 264a and 264b have features that allow them to lock together (e.g., a snap fit or a threaded fit) so that the two dilators can be operated as a unit. In one embodiment, the inner dilator 269 has a proximal hub 264b that includes a swivel connector having internal threads that engage with external threads on the proximal hub 264a of the outer dilator 270. The inner dilator 269 effectively converts the dilator assembly from a 0.035" or 0.038" guidewire-compatible dilator to a 0.018" or 0.014" guidewire-compatible dilator and extends from the distal end of the outer dilator. In one embodiment, as Fig.16 As shown, the inner dilator has an angled tip 276 that is bent or angled relative to the longitudinal axis of the rest of the dilator. In one embodiment, the angle is a 45 degree angle. The angled tip 276 allows the user to more easily introduce a guidewire into one or another branch vessel. The inner dilator may have a Fig.15 straight tapered end as shown or as Fig.16Angled tip as shown. Alternatively, the inner dilator may have a constant outer diameter leading to the distal end with a rounded leading edge. In one embodiment, the inner dilator has a radiopaque marker 274 at or near the distal tip to aid in visualization of the dilator under fluoroscopy. In one embodiment, the inner dilator is reinforced to make it easier to twist to help guide the angled tip in a particular direction. For example, the dilator may have a coiled or braided reinforcement layer. Once the interventional guidewire is in place, the two-part dilator is removed and the guidewire can then be used to insert the interventional device through the arterial sheath into the artery and advance it to the treatment site.

[0087] Fig.17 An alternative embodiment shown allows two separate guidewire sizes to be used with the dilator.This embodiment includes a dilator 1705 having two guidewire lumens extending along the length of the device. Fig.17 The distal end of this embodiment is shown. Fig.18 As can be more clearly seen in the cross-sectional view of , one lumen 1805 is configured for a 0.035" or 0.038" guidewire, while the other lumen 1815 is for a 0.014" to 0.018" guidewire. In this embodiment, the larger lumen 1805 is centered about the centerline of the cone 268, while the smaller lumen 1815 is offset from the centerline of the cone. In this configuration, the access sheath is introduced into the artery along the larger guidewire located within the larger lumen 1805. Once positioned, an interventional guidewire can be placed through the second lumen 1815. The larger guidewire and dilator are then removed from the access sheath and the interventional guidewire can then be used to insert the interventional device through the arterial sheath into the artery and advance it to the treatment site as described above.

[0088] Sheath Guidewire

[0089] The arterial access sheath is typically introduced into the artery over a sheath guidewire having a diameter of 0.035" or 0.038" . The inner diameter and taper length of the distal tip of the dilator are sized to fit with such a guidewire. For example, some sheath sizes for radial artery access are designed to accommodate a sheath guidewire having a diameter of 0.018" , with the corresponding dilator having a distal tip inner diameter and taper length. The sheath guidewire may have an atraumatic straight, angled, or J-shaped tip. The guidewire smoothly transitions to a stiffer section on the proximal end. This configuration allows the guidewire to be introduced and advanced into the artery atraumatically while allowing the sheath to be supported as the sheath is introduced into the artery over the guidewire. Typically, the transition from the atraumatic tip is approximately 4 to 9 cm from the stiffer section. The sheath is typically inserted 15 to 20 cm into the artery so that the stiffer section of the guidewire is at the arterial access site when the sheath is inserted.

[0090] However, in the case of a transcarotid entry point, the amount of the guidewire that can be inserted is much less than 15cm before potentially causing damage to the distal blood vessel. In the case of transcarotid entry for arterial stenting or PTA surgery, it is very important to limit the guidewire insertion length to avoid the risk of distal emboli produced by the sheath guidewire at the diseased part of the carotid artery. Therefore, it is desirable to provide a guidewire that can provide support for a possible steep sheath entry angle while limiting the insertion length. In one embodiment, the transcarotid sheath guidewire has an atraumatic terminal segment, but has a very distal and short transition to a harder segment. For example, a softer terminal segment is 1.5 to 2.5cm, followed by a transition segment of 3 to 5cm in length, followed by a harder proximal segment, wherein the harder proximal segment includes the remainder of the guidewire. In some embodiments, the softer tip segment (i.e., the distal-most flexible segment comprising the distal end of the guidewire) is between 1 cm and 2 cm, and the transition segment positioned between the flexible distal-most segment and the more rigid core segment extending proximally from the transition segment is between 3 cm and 5 cm.

[0091] The sheath guidewire may have a guidewire marker 318 to help the user determine the position of the end of the guidewire relative to the dilator. For example, there may be a mark corresponding to when the end of the guidewire is about to leave the end of the micro-entry cannula on the proximal end of the guidewire. This mark will provide fast guidewire position feedback to help the user limit the amount of insertion of the guidewire. In another embodiment, the guidewire may include additional markings to let the user know that the guidewire has left the distance set by the cannula, for example 5cm.

[0092] Micro-entry components

[0093] Reference Figure 1, a micro-entry kit 100 for initial trans-arterial access includes an access needle 120, an access guidewire 140, and a micro-entry cannula 160. The micro-entry cannula 160 includes a body 162 and an inner dilator 168 slidably positioned within the lumen of the body 162. Typically, for arterial access, the initial needle puncture may use a 21G or 22G access needle, or an 18G needle in the case of a modified Seldinger technique. For trans-carotid access, it may be desirable to use an even smaller needle puncture for access. Carotid puncture access is typically more challenging than femoral puncture access. The carotid artery is a thicker-walled artery, surrounded by a tissue sheath called the carotid sheath, and it is not anchored by surrounding muscle tissue, so the initial needle puncture on a more unstable artery is more difficult and must be completed with greater force, thereby increasing the risk of misplaced puncture, arterial dissection, or posterior wall puncture. A smaller initial needle puncture (e.g., a 23G or 24G needle) increases the ease of needle access and reduces these risks. Accordingly, the sheath guidewire size should be designed to fit within a smaller needle, such as a 0.016" or 0.014" guidewire. The access needle 120 may include a textured surface on the distal end to make it visible under ultrasound, thereby aiding ultrasound-guided insertion of the needle into the artery. The needle length may range from 4 cm to 8 cm.

[0094] like Fig.19A and 19BAs best shown in , the access needle 120 can also include a visible depth indicator 124 located near the distal end of the needle shaft. The visible depth indicator 124 can be visible to the user without the aid of ultrasound or radiography or other imaging techniques, which provides a reference for the user during needle insertion and provides for manipulation of the guidewire during direct insertion into the blood vessel. The access needle 120 (which can be a 21G, 22G, 23G or 24G needle) can have an elongated shaft that defines an inner cavity and is coupled to a proximal hub 122. The shaft length from the distal end of the needle hub 122 to the distal end of its shaft can be between 30 mm and about 100 mm. In some embodiments, the shaft length is about 40 mm or 70 mm. The visible depth indicator 124 can be positioned on the elongated shaft of the needle 120, a distance D from the distal end of the needle 120, for example, about 3 mm to about 7 mm, or preferably 4.5 mm to 5 mm. In some embodiments, the depth indicator 124 can have a width W of about 1 mm to about 2 mm, so that the indicator 124 is easily visible to the naked eye during use, such as directly entering the common carotid artery (CCA). The presence of the depth indicator 124 reduces the risk of the operator advancing the access needle 120 to or through the opposing wall of the blood vessel. The advancement of the needle 120 into the blood vessel can be visually measured by evaluating the amount of advancement of the depth indicator 124 into the blood vessel, which is a known distance away from the distal end. The depth indicator 124 can be formed using chemical etching, laser etching, silk screen printing or other marking methods.

[0095] The entry guide wire typically used in the micropuncture kit can have a relatively long distal soft section, such as between 30-50mm. However, in some applications such as transcarotid artery revascularization (TCAR), the operator may want to advance the guide wire to only 30-40mm in the blood vessel to avoid the end of the guide wire from being advanced to the diseased section of the artery. For the guide wire with a longer distal soft section, only the front 30-40mm of the guide wire is inserted, which means that the support section of the guide wire remains outside the blood vessel, and only the non-supporting part of the guide wire can be used to advance the sleeve and dilator. There is a higher risk of causing damage to the inner surface of the blood vessel by advancing the micro-entry sleeve and dilator along the non-supporting section of the guide wire. Therefore, the entry guide wire described herein has a shorter distal soft section, which allows a shorter length to be inserted into the blood vessel, while still ensuring that the more rigid proximal support section can be used in the blood vessel to advance the sleeve and dilator along it.

[0096] The guidewire 140 described herein can have a shorter distal-most flexible section that terminates at the distal end, for example, the flexible section is only 1 cm to 2 cm long. The transition section proximal to the distal-most flexible section rigidly transitions proximally toward a more rigid core section extending proximally from the transition section. This micro-entry guidewire typically has a diameter of 0.018", with its distal-most flexible section being approximately 1-2 cm and the transition section being 5-6 cm, thereby extending the remaining length of the guidewire with a more rigid core section. In one embodiment, the diameter of the transcarotid entry guidewire is from 0.014" to 0.018", and has a distal-most flexible section of 1 cm, with a transition section of 2-3 cm bringing the rigid support core section closer to the distal end. This will allow the user to have good support for micro-entry cannula insertion, even if the entry angle is steep and the guidewire insertion length is limited.

[0097] As with the sheath guidewire, the microaccess guidewire 140 can have at least one guidewire marker or depth indicator 143 visible to the naked eye, located a known distance from the distal end of the guidewire 140 to help the user determine the distal end of the guidewire 140 relative to the blood vessel and other components of the microaccess system 100 (e.g., the access needle 120, the microcannula 160, and / or the inner dilator 168 (see Figure 1 and 19A )). The depth indicator 143 can provide rapid guidewire position feedback without the need for any other visualization techniques such as ultrasound or radiography to help the user limit the amount of guidewire insertion. For example, the depth indicator 143 can be located at a first position of the guidewire 140 at a distance from the distal end of the guidewire 140, and the distal end of the guidewire 140 is aligned with another part of the system 100 (e.g., the proximal end of the cannula 160) corresponding to the end of the guidewire 140 is about to leave the microcannula 160. In another embodiment, the guidewire 140 may include additional markings 143 to let the user know that the guidewire 140 is about to leave the dilator or has left a set distance (e.g., 5 cm). In another embodiment, the guidewire 140 may include another marking 143 positioned further away to let the user know that when the guidewire 140 is inserted through the entry needle 120, the guidewire 140 is about to leave the entry needle 120 or has left the set distance. Thus, the guidewire 140 can include a plurality of markings 143 that together provide a visual guide related to insertion depth and the relative extension of the guidewire 140 with respect to other system components.

[0098] Figures 20A-20CAn embodiment using at least one visible depth indicator on the access guidewire 140 is shown, which can provide the user with rapid guidewire position feedback and a measurement of the advancement of the guidewire 140 relative to the blood vessel and other components of the system 100 when a portion of the depth indicator is positioned relative to another portion of the system 100, without requiring any special visualization technology other than the user's own eyes. For example, this visual reference provides information about the distance that the guidewire 140 extends beyond the access needle 120 and into the blood vessel. The guidewire 140 can include at least one visible depth indicator 143, a known distance D from the farthest or distal end of the guidewire 140. The visible depth indicator 143 can have a known width W extending between the proximal edge and the distal edge of the indicator 143. For example, one depth indicator 143 can be 2 cm wide, and the distal edge of the depth indicator 143 is positioned 10 cm from the distal end of the guidewire 140, so that the proximal edge of the depth indicator 143 is 12 cm from the distal end of the guidewire 140. The distance away from the distal tip of the guidewire 140 is measured from the distal tip of the guidewire 140 to the distal edge of at least one visible depth indicator 143. When the access guidewire is inserted through the lumen of the elongated shaft of the access needle 120, the distal edge of the depth indicator 143 is aligned with the rear end of the proximal hub 122 of the access needle 120, which causes the distal tip of the guidewire 140 to extend beyond the distal tip of the elongated shaft by a certain extended length. The access guidewire 140 is further advanced through the lumen of the elongated shaft of the access needle 120 until the proximal edge is aligned with the rear end of the proximal hub 122 of the needle 120, which causes the distal tip of the guidewire 140 to extend beyond the distal tip of the elongated shaft of the access needle 120 by the extended length plus the width of the depth indicator 143. For example, the guidewire 140 is advanced through the needle 120, which can be measured as 7 cm from the rear end of the proximal hub 122 to the distal tip of the needle. The guidewire 140 is advanced through the entry needle 120 until the distal edge of the depth indicator is aligned with the rear end of the needle hub 122, which provides an extended length 141 of the guidewire 140, a portion of the guidewire 140 extending away from the distal end of the needle 120, which is as long as 3 cm (see Fig. 20B ). The guidewire 140 is advanced through the needle 120 until the proximal edge of the depth indicator is aligned with the rear end of the needle hub 122, which provides an extended length of the guidewire 140, which is further away from the distal end of the needle 120, which is an additional 2 cm or a total of 5 cm (see Fig. 20C ). It will be appreciated that the guidewire 140 may have a plurality of discrete markings 143 indicating various extension lengths 141 and thereby depths in the blood vessel (e.g., 1 cm, 2 cm, 3 cm, etc.). One or more markings 143 can be formed by chemical etching, laser etching, silk screen printing, or other methods.

[0099] Typically, the micro-entry cannula 160 includes a cannula body 162 that is configured to receive an inner dilator 168 through its inner lumen, the dilator 168 having a tapered end. The inner dilator 168 provides a smooth transition between the cannula 160 and the entry guidewire 140. The cannula 160 is sized to receive a 0.035" guidewire having an inner diameter ranging from about 0.037" to about 0.041". In one embodiment, the micro-entry cannula 160 is configured for transcarotid access. For example, the dilator 168 of the cannula 160 may be sized for a smaller 0.014" entry guidewire 140. In addition, the cannula 160 may have one or more visual depth markings 165 to help the user assess the amount of insertion of the cannula 160 without requiring any special imaging other than the naked eye, as described in more detail below. Radiopaque materials (e.g., barium, bismuth, tungsten) can be added to the entire shaft polymer of the microentry cannula 160 and / or dilator 168 to provide visibility during fluoroscopy. Alternatively or additionally, the microentry cannula 160 and / or dilator 168 can have one or more radiopaque markers 164, for example, at the distal tip of the cannula 162 or dilator 168 to help the user see the tip position during fluoroscopy. This is useful, for example, in situations where the user may want to position the cannula in the ICA or ECA.

[0100] like Figures 21A-21B As shown in , the micro-entry cannula 160 can include a plurality of depth indicators 165 having a known width W and located a known distance D from the distal-most end of the cannula 160. Each of the plurality of visible depth indicators 165 can identify the distance from the distal end of the cannula 160. The indicator 165 can provide a quick measurement of the advancement of the cannula 160 into the blood vessel relative to the insertion point and other components of the system 100 without requiring any special visualization techniques such as ultrasound or radiography. Additionally or alternatively, each of the plurality of visible depth indicators 165 can be formed by a plurality of markings 2165 (e.g., circumferential rings). Although the markings 2165 are described herein as circumferential rings, it should be understood that the markings 2165 need not completely surround the cannula and can take other shapes, such as dots, dashed lines, or other visible markings.

[0101] Each depth indicator 165 has at least one marking 2165. The plurality of markings 2165 forming each of the plurality of depth markings 165 can identify a plurality of increments at which the depth indicator 165 is positioned from the distal tip of the cannula 160. This allows the total distance to be quickly and easily estimated simply by looking at the number of markings 2165 forming each depth indicator 165. In other words, each depth indicator 165 can indicate its distance from the distal tip of the cannula 160 based on the number of markings 2165 (dots, dashed lines, bands, or circumferential rings) forming a particular depth indicator 165. For example, as shown in FIG. Figures 21A-21B As best shown in FIG. 1 , a first depth indicator 165a can be formed of a single circumferential ring 2165 positioned such that the center of the ring 2165 is a first distance from the distal tip (e.g., 10 mm). A second depth indicator 165b can be formed of two circumferential rings 2165 positioned such that the center between the pair of rings 2165 is a second distance from the distal tip (e.g., 20 mm). A third depth indicator 165c can be formed of three circumferential rings 2165 positioned such that the centers of the three rings 2165 are a third distance from the distal tip (e.g., 30 mm). A fourth depth indicator 165d can be formed of four circumferential rings 2165 positioned such that the centers of the four are a fourth distance from the distal tip (e.g., 40 mm). The depth indicators 165 can continue in this pattern, thereby measuring the distance from the distal tip by standard increments in a manner that is quickly visible and immediately understandable to the user.

[0102] It should be understood that the measured distance need not be from the distal tip to the center of the ring as described above, but can instead be from the distal tip to the distal edge of the marker 2165 or from the distal tip to the proximal edge of the marker 2165. Additionally, one of the depth indicators 165e can be a solid mark of known width, the center (or distal edge or proximal edge) of which marks a known distance from the distal tip of the cannula 160, which is generally considered to be the upper depth demarcation line. In some embodiments, the microentry cannula 160 is only inserted between 20-30 mm, and the upper depth demarcation line can be generally about 50 mm. These distances can vary, and more or fewer depth indicators 165 are contemplated herein. For example, if an additional external depth indicator 165 is desired, the marking increment can be identified by the marking mode as described above, such as 1 mark, 2 marks, 3 marks, 4 marks, solid band, and then restart with 1 mark, 2 marks, 3 marks, 4 marks, solid band, etc. The solid band that breaks the marking pattern provides an indication that can be quickly and easily identified, wherein the fifth marking increment in the series has been reached without requiring the user to count too many rings. For example, each depth indicator 165 is tedious for identification and causes user reading errors when it exceeds 4 markings. In addition, the incremental size of 10mm is generally easy to calculate quickly. However, it should be understood that other incremental sizes (such as 5mm, 15mm or even 20mm) can be considered for longer sleeves. One or more of the depth indicators 165 can be distinguished based on their color and by the number and / or pattern of the mark. For example, the first mark can be the first color, the second mark can be the second color, the third mark can be the third color, etc. The mark can be easily distinguished to indicate the depth of insertion (for example, white, yellow, orange, red, green, blue, black, etc.). The mark can be within the range of similar color groups, but with increased intensity or hue to distinguish the insertion depth (for example, the first mark of light pink is towards the last mark of dark red).

[0103] The depth indicator 165 can be formed by silk screen printing, laser marking, adding colorants to the cannula material, or other methods. Other components of the microentry kit 100 can include similar metering marks as described above. For example, the depth indicator 143 of the guidewire 140 can also be metered to indicate the distance from the distal end based on the number of marks (or colors, sizes, shapes) of each indicator 143. As described above, the sheath body 220 and / or the sheath stop 1105 can include one or more marks that provide an indication of the insertion depth of the sheath 220.

[0104] Example Kits:

[0105] Any or all of the above devices may be provided to the user in kit form such that one or more components of the system are included in a common package or batch of packages.One embodiment of an access sheath kit includes an access sheath, a sheath dilator, and a sheath guidewire all configured for transcarotid access as described above.

[0106] In one embodiment, the microaccess kit includes an access needle, a microaccess guidewire, and a microaccess cannula and a dilator, wherein the guidewire is 0.014" and the microaccess cannula and dilator are sized to be compatible with the 0.014" guidewire.

[0107] In one embodiment, an access kit includes an access sheath, a sheath dilator, a sheath guidewire, an access needle, a micro-access guidewire and a micro-access cannula, and a dilator all configured for transcarotid access.

[0108] In an alternative embodiment, the access guidewire is also used as a sheath guidewire. In this embodiment, the access kit includes an access needle, an access guidewire, an access sheath, and a dilator. The sheath and dilator use the access guidewire to be inserted into the blood vessel, thereby avoiding the steps required to change to a larger sheath guidewire. In this embodiment, the dilator taper length and lumen size are designed to be compatible with a smaller access guidewire. In one embodiment, the access guidewire is 0.018". In an alternative embodiment, the access guidewire is 0.016". In an alternative embodiment, the access guidewire is 0.014".

[0109] Exemplary methods:

[0110] An exemplary method of using the transcarotid access system is now described. In an exemplary transcarotid procedure for treating carotid stenosis, the user begins by performing a subsection of the common carotid artery. The user then inserts the access needle 120 into the common carotid artery at the desired access site. An access guidewire 140 with a taper configured for transcarotid access is inserted through the needle into the common carotid artery and advanced into the CCA. The access needle 120 is removed and a micro-entry cannula 160 is inserted into the CCA along the guidewire 140. The micro-entry cannula is inserted into the desired depth using the markings 165 on the cannula as a guide to prevent over-insertion.

[0111] The user removes the dilator 168 and the guide wire 140 in the cannula, leaving the cannula 162 in place. If desired, the user performs angiography through the cannula 162. The user then places the sheath guide wire 300 through the cannula, using the guide wire marker 318 to help insert the guide wire to the desired insertion length. The cannula 162 is removed from the guide wire and the entry sheath 220 and the sheath dilator 260 are inserted into the CCA as a component along the sheath guide wire 300. The sheath stop flange 1115 of the sheath stop 1105 limits the insertion length of the arterial sheath. Once positioned, the dilator 260 and the guide wire 300 are removed. The sheath is then sutured to the patient using the fixing eyelet 234, the rib 236 and / or the suture groove 1120a. The interventional procedure is then performed by guiding the interventional device to the proximal end of the arterial sheath through the hemostatic valve 226 and to the desired treatment site. During the operation, contrast medium injection can be performed as desired via the flushing arm 228 on the arterial sheath 220.

[0112] Alternatively, the user inserts the access needle 120 directly into the common carotid artery at the desired access site, visually monitoring the depth indicator 124 on the needle 120. The vessel wall thickness is typically 1-2 mm, and the vessel diameter of the common carotid artery is typically 8-9 mm. Thus, keeping the depth indicator 124, located 5 mm from the distal tip, within the field of view outside the vessel ensures that the distance the needle is inserted will fully penetrate the wall thickness without contacting the back side of the vessel wall.

[0113] Alternatively or additionally, an access guidewire 140 configured for transcarotid access is inserted through the hub 122 of the needle 120 until a portion of the depth mark 143 is aligned with another portion of the needle 120, which indicates that the desired amount of the extended length 141 of the guidewire 140 is positioned within the common carotid artery. For example, the proximal edge of the depth mark 143 on the guidewire 140 can be aligned with the rear end of the needle hub 122, indicating that 5 cm of the guidewire is advanced beyond the distal tip of the needle 120 into the common carotid artery. Alternatively, the distal edge of the depth mark 143 is aligned with the rear end of the needle hub 122, indicating that 3 cm of the guidewire is advanced beyond the distal tip of the needle into the common carotid artery.

[0114] The entry guide wire 140 is left in place and the entry needle 120 is carefully withdrawn from the blood vessel. A micropuncture cannula 160 having an inner dilator 168 extending through its lumen is advanced into the blood vessel along the entry guide wire 140 by puncture. The depth mark 165 of the micropuncture cannula 160 is visually monitored by the user to confirm the desired depth of insertion of the micropuncture cannula and to prevent over-insertion. Once the desired depth is reached, the micropuncture cannula 160 is left in place and the dilator 168 and the entry guide wire 140 are carefully withdrawn.

[0115] Alternatively, the sheath guidewire 300 is placed into the CCA via a single needle puncture using a larger access needle (e.g., an 18G needle). In this embodiment, an access cannula and access guidewire are not required. This embodiment reduces the number of steps required to access the artery and may be desirable to the user in some situations.

[0116] Alternatively, the sheath dilator is Fig.15 A two-part sheath dilator assembly 260 is shown having an inner dilator 269 and an outer dilator 270. The outer dilator 270 is configured to receive a 0.035" sheath guidewire 300 and provide a smooth transition from the 0.035" guidewire to the entry sheath 220. The inner dilator 269 is configured to receive a smaller guidewire in the range of 0.014" to 0.018" and provide a smooth transition from the smaller guidewire to the outer dilator 270. Once the sheath guidewire is positioned within the CCA, the entry sheath and outer sheath dilator 270 are inserted into the CCA over the 0.035" sheath guidewire 300. The guidewire is then removed and the intrathecal dilator 269 is inserted into the extrathecal dilator. In one embodiment, the intrathecal dilator has a Fig.16 Angled tip 276 is visible in the figure. An interventional 0.014" guidewire is inserted through the intrathecal dilator and guided to the target treatment site using the angled tip to aid in guidewire positioning. Alternatively, the intrathecal dilator has a straight tip and is used to help securely position the guidewire within the CCA. Once the 0.014" guidewire is positioned at or passed through the target treatment site, the sheath dilator 260 and sheath 0.035" guidewire 300 are then removed and the intervention is performed.

[0117] In an alternative embodiment, the sheath dilator is a dual lumen sheath dilator 1705. In this embodiment, the sheath and dilator are inserted over a sheath guidewire 300, wherein the sheath guidewire is located within the larger lumen 1805 of the dilator 1705. Once the sheath and dilator are in place, an interventional 0.014" guidewire is positioned through the smaller lumen 1815. The dilator provides distal support and maintains the axial position of the sheath tip within the vessel lumen, allowing advancement of the 0.014" guidewire to be safer and easier than would otherwise be possible if the dilator was removed and the sheath tip was at least partially directed toward the posterior wall of the artery. Once the 0.014" guidewire is positioned at or through the target treatment site, the sheath dilator 1705 and sheath 0.035" guidewire are then removed and the intervention is performed.

[0118] In yet another embodiment, it may be desirable to occlude the CCA during intervention to minimize the antegrade flow of emboli. In this embodiment, the occlusion step may be performed via a vascular surgical approach (such as using a vascular hoop, a tourniquet, or a vascular clamp). In an alternative embodiment, the access sheath 220 has an occlusion element such as an occlusion balloon 805 on the distal end. In this embodiment, the balloon is inflated when the CCA occlusion is desired. In yet another variation, although the CCA is occluded surgically or via balloon occlusion, it may also be desirable to connect the arterial sheath to a shunt, such as to establish a reverse flow system around the area of ​​the treatment site to minimize distal emboli. In this embodiment, the arterial sheath 220 has a Y-shaped connection to a flow line 1005. The flow line 1005 can be connected to a return site with a pressure lower than the arterial pressure to establish a pressure gradient that causes a reverse flow through the shunt, such as an external reservoir or a central venous return site (such as the femoral vein or internal jugular vein). Alternatively, the flow line may be connected to a pumping source such as a pump or syringe.

[0119] In another embodiment, the transcarotid access system is used to perform percutaneous neurointerventional procedures. In this embodiment, the user performs percutaneous puncture of the common carotid artery CCA using the access needle 120 at the desired access site. Ultrasound can be used to accurately determine the appropriate access site and guide needle puncture. The access guide wire 140 is inserted into the common carotid artery through the needle and moved forward into the CCA. The access needle 120 is removed and the micro-access cannula 160 is inserted into the CCA along the guide wire 140. The user removes the cannula intradulator 168 and the guide wire 140, thereby leaving the cannula 162 in place. If desired, the user performs angiography through the cannula 162. The user then places the sheath guide wire 300 through the cannula, using the guide wire marker 318 to help the desired insertion length. The cannula 162 is removed from the guide wire and the access sheath 220 and the sheath dilator 260 are inserted into the CCA as a component along the sheath guide wire 300.

[0120] Alternatively, a smaller access guidewire 140 is used to position the access sheath 220 and sheath dilator 260 within the CCA. In this embodiment, the sheath dilator tapered tip 268 has been configured to smoothly transition from the access guidewire 140 to the access sheath 220. In one variation, the access needle is 21G and the access guidewire is 0.018". In another variation, the access needle is 24G and the access guidewire is 0.014". Once the sheath is in place, the guidewire and sheath dilator are removed and the interventional procedure is then performed by guiding the interventional device through the hemostasis valve 226 on the proximal end of the arterial sheath and directing it to the desired treatment site. Contrast injections can be performed as desired during the procedure via the flush arm 228 on the arterial sheath 220.

[0121] Alternatively, it may be desirable to advance the sheath further into the ICA once it is positioned within the CCA, such as the mid-to-distal cervical ICA, the petrous ICA, or beyond. In this embodiment, the sheath dilator may be replaced with a softer sheath dilator so that the sheath may be advanced without damaging the distal ICA. In this embodiment, the softer dilator has a distal radiopaque marker so that the user can easily see the leading edge of the sheath and dilator assembly during positioning of the sheath. Once the sheath is positioned, the dilator and sheath guidewire may be removed and an intervention may be performed. Alternatively, once the sheath is positioned within the CCA, the 0.035" guidewire may be removed and an inner dilator with a smaller guidewire in the range of 0.014" to 0.018" may be inserted into the sheath dilator. The sheath dilator assembly with the inner dilator and the smaller guidewire may then be positioned further out of the ICA with reduced risk of vascular trauma.

[0122] In one embodiment, it may be desirable to occlude the CCA or ICA during various stages of the operation to reduce the chance of distal emboli flowing to the brain. In this embodiment, the CCA or ICA is occluded by means of an occlusion balloon 805 on the access sheath 220. It may also be desirable to connect the arterial sheath to a shunt, for example to form a reverse flow system around the area of ​​the treatment site to minimize distal emboli. In this embodiment, the arterial sheath 220 has a Y-shaped connection to the flow line 1005. The flow line can be connected to a reflux site with a pressure lower than the arterial pressure to form a pressure gradient that causes reverse flow through the shunt. Alternatively, the flow line can be connected to a pumping source such as a pumping pump or a syringe.

[0123] Although this specification contains many details, these details should not be interpreted as a limitation on the scope of the invention for which a patent is claimed or may be claimed, but rather as a description of features specific to a particular embodiment. Certain features described in the context of a separate embodiment in this specification may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. In addition, although the above features are described as working in certain combinations and even initially claiming patent rights, one or more features in the combination claiming patent rights may be separated from the combination in some cases, and the combination claiming patent rights may be directed to a sub-combination or a variation of a sub-combination. Similarly, although operations are depicted in the drawings in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequential order shown, or to perform all illustrated operations to achieve the desired result.

[0124] Although various methods and apparatus embodiments are described in detail herein with reference to certain variations, it should be understood that other variations, embodiments, methods of use, and combinations thereof are also possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments herein.

Claims

1. A micropuncture kit for direct access to the lumen of a surgically exposed blood vessel using direct visual guidance, the kit comprising: a micropuncture access needle comprising a proximal hub coupled to an elongated shaft defining an inner lumen and an access needle visible depth indicator positioned on the elongated shaft; a microentry cannula comprising an elongated body defining an inner lumen and a plurality of microentry cannula visible depth indicators formed on the elongated body, wherein each of the plurality of visible depth indicators identifies a distance from a distal tip of the cannula; an access guidewire sized to be received through the lumen of the micropuncture access needle, the guidewire comprising a distal tip and a first visible depth indicator, a second visible depth indicator, and a third visible depth indicator, each visible depth indicator positioned on the access guidewire a distance away from the distal tip of the guidewire; and wherein the first visible depth indicator is aligned with the proximal edge of the micro-entry cannula to provide a visual indication to a user that the distal end of the entry guidewire is aligned with the distal end of the micro-entry cannula; wherein the second visible depth indicator is aligned with the proximal edge of the micro-entry cannula to provide a visual indication to the user that the distal end of the access guidewire is aligned with the distal end of the micro-puncture access needle; wherein the third visible depth indicator is aligned with the proximal edge of the micro-entry cannula to provide a visual indication to the user that the distal end of the entry guidewire is positioned distal to the distal end of the micro-puncture access needle by a predetermined distance indicated by the third visible depth indicator, wherein each of the first visible depth indicator, the second visible depth indicator, and the third visible depth indicator has a proximal edge, a distal edge, and a width extending between the proximal edge and the distal edge; wherein the distance away from the distal tip of the guidewire is measured from the distal tip to a distal edge of the corresponding first visible depth indicator, second visible depth indicator, or third depth indicator; wherein the access guidewire is inserted through the lumen of the elongated shaft until the distal edge is aligned with the rear end of the proximal hub of the access needle, which causes the distal tip of the guidewire to extend beyond the distal tip of the elongated shaft by an extended length; and The micropuncture access needle visible depth indicator provides an indication of whether the micropuncture access needle, when inserted into a blood vessel, will penetrate the wall thickness of the blood vessel without contacting the back side of the vessel wall of the blood vessel.

2. The kit of claim 1, wherein: The access guidewire includes a distal-most flexible section including a distal tip of the guidewire, a transition section proximal to the distal-most flexible section, and a more rigid core section extending proximally from the transition section.

3. The kit of claim 2, wherein: The distal-most flexible section is between 1 cm and 2 cm, and the transition section is between 2 cm and 3 cm.

4. The kit of claim 2, wherein: The transition section and the core section are configured to support the micro access cannula inserted into the blood vessel.

5. The kit of claim 1, wherein: The outer diameter of the guidewire is in the range of 0.014" to 0.018", and wherein the micropuncture access needle is in the range of from 21G to 24G.

6. The kit of claim 1, wherein: Advancing the access guidewire through the lumen of the elongated shaft until the distal edge is aligned with the rear end of the proximal hub of the access needle extends the distal tip of the guidewire beyond the extended length of the distal tip of the elongated shaft plus the width of a corresponding visible depth indicator.

7. The kit of claim 6, wherein: The extended length is 3 cm and the width of the first visible depth indicator, the second visible depth indicator and / or the third visible depth indicator is 2 cm.

8. The kit of claim 1, wherein: The entry needle visible depth indicator is a chemical etching mark, a laser etching mark, or a silk screen mark.

9. The kit of claim 1, wherein: The first visible depth indicator includes a marking and is 10 mm distal to the distal tip of the cannula.

10. The kit of claim 9, wherein: The second visible depth indicator includes two markings and is 20 mm distal to the distal tip of the cannula.

11. The kit of claim 10, wherein: The third visible depth indicator includes three markings and is 30 mm distal to the distal tip of the cannula.

12. The kit of claim 1, wherein: The access needle visual depth indicator is between 3 mm and 7 mm from the distal tip of the elongated shaft.

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