Persistent perfusion sheath

Abstract

To provide a persistent perfusion sheath assembly for passing an intravascular medical device while maintaining a flow passage in the vessel.SOLUTION: The sheath assembly passes through an arteriotomy site and can include a first lumen 120 configured for the passage of a medical device, and a second lumen 130 configured to allow a flow of fluid from a location in the blood vessel upstream of the arteriotomy site to a location downstream of the arteriotomy site. The sheath assembly can further include a stylet, a sleeve or an additional sheath configured to selectively open and close the flow of blood between upstream and downstream of the arteriotomy site. The sheath assembly can further include a closure device distal of the arteriotomy site, the closure device configured to control the blood flow through the arteriotomy site.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 USC § 119(e) of U.S. Provisional Application No. 62 / 783,554, filed December 21, 2018, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] background Intravascular medical devices such as percutaneous pumps (e.g., the Impella 2.5™ system by Abiomed, Inc., Danvers, Massachusetts), catheters, guidewires, balloon angioplasty catheters, delivery sheaths, and implant delivery systems are commonly used during minimally invasive procedures in the cardiovascular, cerebrovascular, and peripheral vascular systems. Such medical devices may be introduced into a patient in a variety of ways. Blood pump assemblies are introduced surgically or percutaneously through the vascular system during cardiac procedures. Such intravascular procedures are minimally invasive. In one common approach, the pump assembly is inserted by a catheterization procedure through the femoral artery using a sheath, such as a peel-away introducer sheath. The femoral artery is commonly used in such procedures primarily due to its ease of access. A sheath is inserted into the femoral artery through an arteriotomy (an access site in the artery) to create an insertion path for the pump assembly. A portion of the pump assembly is then advanced through the lumen of the introducer sheath and into the artery. Once the pump assembly is inserted, the introducer sheath is removed, e.g., peeled back. A repositioning sheath may then be advanced over the pump assembly and into the arteriotomy.

[0003] The introducer sheath must be large enough in diameter to accommodate an intravascular device, such as a blood pump. Currently, the smallest heart pump available is the Impella 2.5 percutaneous heart pump, which has a motor diameter of approximately 12 Fr. Thus, to introduce an Impella 2.5 pump, the sheath must be at least 13 Fr. Other pumps and devices are larger than the Impella 2.5, for example, the Impella CP pump has a motor diameter of approximately 14 Fr, and the Impella 5.0 pump has a motor diameter of approximately 21 Fr or more, depending on the type of device. For such devices, even larger sheaths are required.

[0004] While existing introducer sheaths are generally functional for device insertion, they have drawbacks. For example, because of their size, introducer sheaths can block the cross-sectional area of ​​the artery, thereby occluding the artery, which can severely restrict downstream blood flow. Restricted blood flow can be problematic for a number of reasons, including causing intermittent claudication, leg numbness / weakness, and limb ischemia that can even result in limb loss.

[0005] Traditionally, limb ischemia is known as a "distal perfusion" problem, meaning that it often occurs downstream from the insertion site of the device. In this disclosure, the "distal" element is the portion of the element located furthest from the clinical practitioner, and "proximal" is the portion of the element closest to the clinical practitioner. In the case of a sheath that is placed inside the patient, the end of the sheath that is placed inside the patient's body is the "distal" end, while the handle or end held by the clinical practitioner that is located outside the patient's body is the "proximal" end.

[0006] For relatively large medical devices (e.g., a maximum outer diameter equal to or greater than 12 Fr), the introducer sheath (or repositioning sheath) used in combination with the medical device has an outer diameter that is substantially similar in size to the inner diameter of the artery or vessel in which the sheath is positioned. This match between the outer diameter of the sheath and the inner diameter of the artery or vessel prevents blood from flowing from a location upstream of the arteriotomy to a location downstream of the arteriotomy. Furthermore, for these relatively large medical devices, the introducer sheath (or repositioning sheath) used in combination with the medical device also requires a large access site; a large access site may be difficult to close or difficult to control bleeding during insertion or retraction of the sheath. The size of the medical device (e.g., relatively large or relatively small), and therefore whether the introducer sheath or repositioning sheath is considered relatively large, may depend on the anatomy of a particular patient.

[0007] Another drawback is that excessive bleeding can occur at the arteriotomy during insertion or removal of the sheath, which can result in patient loss of blood and debilitation. This is usually treated with closure devices such as collagen injections, sutures, or staples. However, these types of closure devices can be difficult to use when blood flow has not yet been adequately stopped and is flooding the access site being closed. Furthermore, these types of closure devices generally require additional tools or steps, and therefore require more time for effective closure.

[0008] The size of the introducer sheath and its impact on the patient can be complicated by the patient's anatomy (e.g., severe stenosis and small vessels) and conditions (e.g., shock, vasospasm, constricted vessels in patients on vasopressors), which can limit the size of introducer that can be used to gain access. In the case of vasospasm, even a sheath that is reasonably sized to the original vessel diameter will fill the entire reduced vessel. Thus, for some patients, even a very small sheath, e.g., a 6Fr sheath, may be too large, leading to concerns about occlusion and access site bleeding, as may a 12Fr sheath in other patients.

[0009] Generally, the above-mentioned drawbacks become even more pronounced for long-term vascular procedures. Certain procedures in the catheterization lab are short and therefore pose less risk; for example, they typically last only 4-5 hours at most, and physicians periodically check distal (limb) perfusion. However, even in short-term situations, physicians may forget to ensure that patients are getting adequate distal perfusion from the device or miss warning signs of inadequate limb perfusion. In addition, certain patients may be transferred to the ICU with introducer or repositioning sheaths remaining in the patient for longer periods of time, ranging from 1-14 days. In such cases, problems of vascular occlusion and associated limb ischemia, as well as access site bleeding, may worsen.

[0010] One known intervention for blocked femoral arteries is femoral-femoral bypass for arterial revascularization. The technique involves gaining access, usually with a small sheath (e.g., a 4Fr catheter), to the leg opposite the primary access site; gaining access with a similar sheath to a distal portion of the same leg as the primary access site; and connecting the two sheaths together to allow perfusion of the patient's primary access leg with blood flow from the opposite leg. However, such interventional procedures are associated with other risks, including difficulty in gaining access to the distal portion of the blocked leg (due to poor blood flow, blood pressure, pulsatility, or a combination of these), additional allocation of resources (time, material use, and extra components), increased risk of infection, and other risks associated with multiple access sites. Another possible intervention is the use of ECMO. However, such interventional procedures are associated with similar challenges and other difficulties as those faced with femoral-femoral bypass.

[0011] One possible intervention to address access sites with unwanted heavy bleeding is to close the access site with collagen or metal clips or sutures, but such interventions are usually unplanned and hasty, and may be difficult to visualize amid ongoing bleeding at the access site itself. Summary of the Invention

[0012] overview The systems, methods, and devices described herein provide an improved sheath for not only delivering an intravascular device, but also restoring blood perfusion in a patient distal to the device, for example, in the lower leg distal to an occluded vessel. Advantages may be realized. In some embodiments, distal perfusion may be achieved without removal of the sheath. Distal perfusion may be achieved with a limited or reduced number of access sites (as opposed to femoral-femoral artery bypass systems). The systems, methods, and devices described herein restore blood circulation in the patient's vasculature (usually the lower leg) with minimal additional steps. Means for determining the position of the arteriotomy along the length of the catheter to help achieve more efficient positioning, and means for positioning the stylet relative to the location of the arteriotomy, are also disclosed herein.

[0013] The systems, methods, and devices described herein further provide a sheath with an integrated closure device that prevents unwanted bleeding at the access site without the need for additional medical procedures (collagen injection or suturing) or without the need for sheath removal. In some embodiments, the integrated closure device is positioned upstream from the arteriotomy. In other embodiments, the integrated closure device is positioned at the arteriotomy. In some embodiments, the integrated closure device is deployed by inflation. In other embodiments, the integrated closure device is deployed by mechanical expansion.

[0014] In one aspect of the present disclosure, a sheath system is provided having a sheath with a lumen through which a medical device may be inserted and a mechanism configured to allow fluid flow from a blood vessel to flow either through or around the sheath without being substantially blocked from reaching an area of ​​the patient downstream from the sheath. The mechanism may be configured with a second lumen, one or more apertures, an expandable portion, or other means for allowing blood flow from a portion of the artery upstream from the sheath to a portion of the artery downstream from the device.

[0015] In some embodiments, the sheath assembly is configured with a second lumen that allows blood to flow around the sheath. For example, the second lumen may run alongside the sheath (e.g., a side-rigger) or may run inside the sheath. The lumen has a first end with a first inlet port and a second end with an outlet port; where the inlet is positioned at or near the distal end of the sheath and the outlet is positioned on the opposite side of the sheath, thereby allowing blood to enter the inlet end and exit the lumen on the opposite side of the sheath. To prevent blood from altogether exiting the vessel, a stylet may be provided and configured to selectively open and close the second lumen along a longitudinal axis when the first end of the sheath body is positioned within the blood vessel and the second end of the sheath is outside the patient.

[0016] In other adaptations, the sheath assembly is configured with apertures in the sheath itself and a covering for the apertures that is removable to allow blood to flow through the apertures. The covering may include a second, outer sheath that is retractable (e.g., by a physician) to expose the apertures in the sheath to allow blood to flow into the sheath and out through the apertures to reach the downstream vasculature. The covering may include an inner device, such as a stylet, positioned within the sheath and configured to be retracted to expose the apertures in the sheath.

[0017] In other suitable configurations, one or more channels or other components are provided on the exterior of the sheath surface to allow blood to flow past the sheath. For example, one or more balloons may be used to encourage blood flow past the sheath. In some arrangements, a balloon is affixed to the exterior of the sheath and, when inflated, expands the blood vessel adjacent the sheath to allow blood to flow around the exterior of the sheath. A second sheath downstream of the first sheath may be used to encourage blood flow from upstream to downstream of the first sheath. A sheath with an expandable distal end may be used to increase the diameter of the artery in which the sheath is placed, and may allow blood to flow into the distal end of the sheath, through the expandable distal end, and into the artery downstream of the expandable distal end.

[0018] A method for inserting a medical device into a patient through a sheath system, such as a percutaneous method for inserting a medical device into a patient's blood vessel, is also contemplated. The method includes inserting a sheath assembly into an artery at an arteriotomy through a skin puncture and passing a medical device through the sheath assembly. The method further includes manipulating the sheath assembly to allow blood flow between a location upstream and a location downstream from the arteriotomy while simultaneously ensuring hemostasis through the arteriotomy. At least one benefit of the method is to increase blood flow between a location upstream and a location downstream from the arteriotomy and to control blood loss at the access site. Larger diameter pumps and pumps with larger components may be suitable for use with the system.

[0019] In another aspect of the present disclosure, a method is provided for placing a sheath within a blood vessel and delivering a device through the sheath with minimal or no downstream ischemia. In some adaptations, a method is provided for percutaneously inserting a medical device (e.g., a large diameter blood pump) into a patient's blood vessel by inserting a sheath assembly that can facilitate delivery of the device to an intended location within the vasculature without significantly occluding the vessel. The method may be used with a sheath having a diameter substantially equal to the cross-sectional diameter of the artery located below the arteriotomy, such that the sheath is wide enough to extend across the diameter of the artery at that location. The method further includes passing the medical device through the sheath assembly; and simultaneously ensuring hemostasis through the arteriotomy while allowing blood flow between a location upstream from the arteriotomy and a location downstream from the arteriotomy to reach a downstream region of the patient. In that regard, the method functions to allow blood to flow without being blocked by the sheath. Another benefit of this method is that for a sheath that is relatively large compared to the cross-section of the artery, it prevents excessive blood loss at the access site while allowing blood flow between locations upstream and downstream from the arteriotomy. [Brief description of the drawings]

[0020] These and other objects and advantages will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout.

[0021] [Figure 1] 1A and 1B are isometric and cross-sectional views of an exemplary continuous irrigation sheath according to one embodiment of the present disclosure, respectively; [Diagram 2] Figure 2A is a cross-sectional view of a stylet according to one embodiment of the present disclosure, and Figure 2B is an isometric view of the stylet of Figure 2A. [Diagram 3] 3 is a cross-sectional view of the continuous irrigation sheath of FIG. 1 loaded with the stylet of FIG. 2. [Figure 4] FIG. 4 is an isometric view of an exemplary access setup using the continuous irrigation sheath assembly of FIG. [Figure 5A] FIG. 4 is an isometric view of the loaded sheath of FIG. 3 inserted into a blood vessel. [Figure 5B] FIG. 5B is a cross-sectional view of the sheath assembly of FIG. 5A. [Figure 5C] FIG. 5B is another cross-sectional view of the sheath assembly of FIG. 5A. [Figure 5D] FIG. 5B is another cross-sectional view of a sheath assembly similar to that of FIG. 5A. [Figure 6] FIG. 5C is an isometric view of a medical device inserted into the sheath assembly of FIG. 5B. [Figure 7] FIG. 7 is an isometric view of a medical device inserted into the loaded sheath of FIG. 6 with the stylet partially retracted. [Figure 8] Figure 8A is a cross-sectional view of a stylet similar to that of Figure 2 with a lumen running through the longitudinal length of the stylet body, Figure 8B is a side view of the stylet of Figure 8A with a skive formed in the distal end of the stylet body, and Figure 8C is an isometric view of the distal end of the stylet of Figure 8B. [Figure 9] Figure 9A is a longitudinal cross-sectional view of the sheath assembly of Figure 6 in use to determine if blood from the vessel is flowing through the second lumen of the sheath, and Figure 9B is a longitudinal cross-sectional view of the primed sheath of Figure 6 in use with the stylet fully retracted to ensure that blood in the vessel is flowing through the second lumen of the sheath. [Figure 10] 13 illustrates an exemplary method for adjusting the position of the stylet relative to the sheath for fluid bypass through a second lumen of the sheath. [Figure 11] 1 illustrates an exemplary method for providing adequate limb perfusion while using a sheath assembly. [Figure 12] 13 illustrates an exemplary method for providing adequate limb perfusion while using a sheath assembly by retracting a device occluding the sheath. [Figure 13] An exemplary view of a sheath with a distally expandable portion, based on one embodiment of the present disclosure. [Figure 14] An exemplary method for providing appropriate limb perfusion using the sheath of FIG. 13 is shown. [Figure 15] An exemplary isometric view of a sheath assembly with two sheaths, based on one embodiment of the present disclosure. [Figure 16] An exemplary method for providing appropriate limb perfusion using the sheath assembly of FIG. 15 is shown. [Figure 17] An exemplary view of a sheath with an expandable balloon on the outer surface of the sheath, based on one embodiment of the present disclosure. [Figure 18] FIGS. 18A - B are exemplary cross - sectional views of a sheath with an expandable balloon on the outer surface of the sheath, based on one embodiment of the present disclosure. [Figure 19] An exemplary method for providing appropriate limb perfusion using the sheath of FIG. 17 or FIGS. 18A - B is shown. [Figure 20] An exemplary cross - sectional view of a conventional system for sealing an access site using collagen. [Figure 21] An exemplary cross - sectional view of a sheath system for providing arteriotomy data, based on one embodiment of the present disclosure. [Figure 22] An exemplary method for providing arteriotomy data using the sheath system of FIG. 21 is shown. [Diagram 23] An exemplary method for controlling bleeding at an access site, based on one embodiment of the present disclosure, is shown. [Figure 24] An exemplary view of a closure device disposed upstream of an arteriotomy, based on one embodiment of the present disclosure. [Diagram 25] An exemplary method for controlling bleeding at an access site using the closure device of FIG. 24 is shown. [Figure 26] An exemplary closure device for controlling bleeding at an access site, based on one embodiment of the present disclosure, is shown. [Figure 27] 27A-B show an exemplary closure device for controlling access site bleeding before (FIG. 27A) and after (FIG. 27B) deployment according to one embodiment of the present disclosure. [Figure 28] 28A-B are exemplary top and side views of an exemplary closure device for controlling bleeding at an access site according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Detailed Description Certain exemplary embodiments are described so that the systems, methods, and devices described herein may be fully understood. Although the embodiments and features described herein are specifically described for use in connection with a percutaneous heart pump system, it will be understood that the components and other features outlined below may be combined with each other in any suitable manner and may be adapted and applied to other types of medical devices, such as stents, transcatheter aortic valve replacement (TAVR) delivery systems, cardiac therapy devices, and cardiac assist devices; including balloon pumps, cardiac assist devices implanted using a surgical incision, and other vascular devices.

[0023] The disclosed systems, methods, and devices provide a perfusion sheath assembly for insertion into a patient's blood vessel, the sheath assembly including a lumen configured to pass a medical device therethrough, the sheath assembly further including a mechanism configured to allow substantially unblocked flow of fluid within the vessel to an area of ​​the patient downstream from the sheath, and a closure device configured to prevent flow of fluid out of the vessel through the arteriotomy.

[0024] FIG. 1A illustrates an isometric view of an exemplary continuous perfusion sheath 100 in accordance with certain embodiments of the present disclosure. The perfusion sheath 100 is suitable for insertion into an arteriotomy of a patient, such as the femoral artery. The sheath 100 comprises a sheath body 110 extending along a longitudinal axis 112. The sheath body 110 comprises a distal end 114, a proximal end 116, and an outer surface 118. In certain embodiments, the sheath body 110 is tubular with a circular cross-section, although the sheath body 110 may be of any shape and configuration. The sheath body 110 comprises a first lumen 120 extending between the distal end 114 and the proximal end 116 of the sheath body 110. The sheath body 110 further comprises a second lumen 130 extending between the distal end 114 and the proximal end 116 of the sheath body 110. The first lumen 120 has an inner surface 122, and the second lumen 130 has an inner surface 132. The first lumen 120 is open to allow passage of a medical device, such as a percutaneous pump (not shown), and the second lumen 130 is open to allow fluid from a blood vessel to flow therethrough. One example of such a percutaneous pump is the Impella 2.5™ system (Abiomed, Inc., Danvers, Massachusetts). Such pumps generally include a catheter body with a pump head at a distal end of the catheter body and a handle at a proximal end of the catheter body. It will be understood that although a percutaneous heart pump is described herein, any other percutaneous or intravascular medical device may be used in conjunction with the present disclosure, such as by delivering such a device through a sheath according to the disclosure herein.

[0025] In some embodiments, the first lumen 120 has a circular cross-section with a first diameter 124. The first lumen 120 is sized to allow a medical device to pass through the length of the first lumen 120; that is, the diameter 124 of the first lumen 120 is preferably larger than the maximum diameter of the medical device. In certain embodiments, the first diameter 124 need only be slightly larger than the catheter body of the medical device. Furthermore, in some embodiments, the diameter 124 is selected such that the inner surface 122 of the first lumen forms an interference fit with the outer surface of a medical device inserted within the first lumen 120, while allowing longitudinal movement of the device within the first lumen 120. Such an interference fit ensures that there is minimal or no gap between the medical device and the inner surface 122. This prevents fluid from passing through any space that may occur between the inner surface 122 of the first lumen 120 and the medical device; such fluid may solidify and block the first lumen 120 of the sheath 100. In certain embodiments, the second lumen 130 has a circular cross-section with a second diameter 134. However, it will be understood that although Figure 1A depicts the first and second lumens 120, 130 as having circular cross-sections, these lumens may have any cross-sectional shape.

[0026] 1B shows a cross-section of the perfusion sheath 100 taken along section line A-A' in FIG. 1A. The cross-section shows the sheath body 110, the first lumen 120, and the second lumen 130. In this embodiment, the first lumen 110 has a circular cross-section, while the second lumen 130 has a bean-shaped cross-section. It will be appreciated that the cross-sections of the first lumen 120 and the second lumen 130 are complementary to one another such that their combined cross-sectional area closely matches the cross-sectional area of ​​the sheath body 110 without compromising the mechanical strength of the sheath body 110. This ensures maximum utilization of the available space within the sheath body 110.

[0027] 2A and 2B illustrate a stylet 200 configured to be inserted into the second lumen 130 of the perfusion sheath 100. Insertion and retraction of the stylet 130 into and from the second lumen 200, respectively, allows the second lumen 130 to be selectively closed and opened as needed. For example, during vasospasm, the patient's arteriotomy vessel may contract such that the perfusion sheath 100 completely blocks the vessel, thereby stopping blood flow. In such a situation, the stylet 200 may be partially or fully removed from the second lumen 130 to provide a passageway within the sheath body 110 for blood within the vessel to flow. The stylet 200 has a cross-sectional shape that matches the cross-sectional shape of the second lumen 130 such that when the stylet 200 is inserted into the second lumen 130, it has an interference fit with the inner surface 132 of the second lumen 130. The stylet 200 has the same cross-section throughout its length. The stylet 200 is at least as long as the longitudinal length of the sheath body 110. When fully inserted into the second lumen 130, the distal end 210 of the stylet 200 is aligned with the distal end 114 of the sheath body 110, and the proximal end 220 of the stylet 200 is aligned with the proximal end 116 of the sheath body 110. In the illustrated example of FIGS. 1A, 1B, and 2, the stylet 200 has a bean-shaped cross-section that matches the bean-shaped cross-section of the second lumen 130. However, it will be understood that the stylet may take on any cross-sectional shape necessary to match the cross-sectional shape of the second lumen 130. In other embodiments, the stylet 200 may be longer than the sheath body 110 such that the proximal end 220 is not aligned with the proximal end 116 of the sheath body 110. In some embodiments, the stylet 200 may comprise more than one member. In other embodiments, the stylet 200 may include a lumen running its length, as discussed in a later section. In a further embodiment, the stylet 200 may be completely removed from the second lumen 130 to allow for the insertion of a guidewire to maintain the arteriotomy and target vessel position.

[0028] The sheath body 110 may comprise a flexible material. The flexible material is an elastic material with a modulus of elasticity of approximately 1.6 ksi. Ksi is a unit of pressure that represents thousands of pounds per square inch. In some embodiments, the flexible material is a material with a yield strain of approximately 200%. In some embodiments, the flexible material contains a radiopaque filler, such as bismuth oxychloride or barium sulfate, in a concentration of 5% to 40% by weight. In certain embodiments, the flexible material comprises any one of ethylene vinyl acetate (EVA), styrene-butadiene copolymer (SBC), synthetic rubber, or any other elastomer.

[0029] The stylet 200 comprises a rigid material. The rigid material is a polyethylene or polyurethane material having a modulus of elasticity of about 40 ksi. In some embodiments, the rigid material contains a radiopaque filler, such as bismuth oxychloride or barium sulfate, at a concentration of 5% to 40% by weight. In some embodiments, the rigid material is any one of a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, a low density polyethylene (LDPE) material, polyetheretherketone (PEEK), and a polyether block amide (such as PEBAX). In certain embodiments, the rigid material is a crack resistant material. In some embodiments, the rigid material may also be a material with a low coefficient of friction.

[0030] FIG 3 illustrates a continuous perfusion sheath assembly 300 according to one embodiment of the present disclosure. The sheath assembly 300 includes a continuous sheath 100 as illustrated in FIG 1A and FIG 1B, in which the sheath body 110 has a first lumen 120 for passage of a medical device (not shown) and a second lumen 130 for flow of fluid from the patient's arteriotomy. FIG 3 also illustrates the second lumen 130 being closed by the stylet 200 of FIG 2A and FIG 2B when the stylet 200 is inserted into the second lumen 130 via an interference fit between an outer surface of the stylet 200 and an inner surface 132 of the second lumen 130. In this manner, the stylet 200 seals the second lumen 130 when fully inserted into the second lumen 130 of the sheath 100. The stylet 200 may be inserted into or retracted from the second lumen 130 to selectively control the flow of fluid through the second lumen 130. For example, when fluid flow through the second lumen 130 is desired, the stylet 200 may be fully or partially retracted within the second lumen 130. Conversely, when it is desired to reduce or block the flow of fluid through the second lumen 130, the stylet 200 is at least partially or completely inserted into the second lumen 130.

[0031] FIG. 4 shows an isometric view 400 of a representative access setup using a loaded sheath assembly 430 similar to the sheath assembly 300 in FIG. 3. The sheath assembly 430 has a sheath body 110 with a first lumen 120 and a second lumen 130. FIG. 4 shows a patient's body tissue 405 and a target vessel 410 having an upstream end 412 and a downstream end 414. FIG. 4 also shows an insertion site 450 in the skin and an arteriotomy 440 where the sheath assembly 430 is inserted into the target vessel 410. The sheath body 110 bends as it enters the arteriotomy 440. This bend is critical to selectively control blood flow in the target vessel 410, as discussed in a later section. The sheath assembly 430 has a proximal end 425 and a distal end 420. The sheath assembly 430 has a first portion 432 (distal portion) that resides within the patient's vessel 410 when inserted into the vessel 410, and a second portion 434 (proximal portion) that resides outside the vessel 410. As shown in FIG. 4, the sheath body 110 completely fills the target vessel 410. The sheath assembly 430 is loaded with a stylet 200 (as in FIG. 2) that is positioned within the second lumen 130 of the sheath body 110. The stylet 200 may be inserted or retracted from the second lumen 130 by moving the stylet 200 relative to the sheath body 110 as shown by arrow B in FIG. 4 to control the flow of fluid (e.g., blood) from the distal end 412 to the proximal end 414 in the vessel 410 (fluid flow is shown by arrow C from upstream to downstream in FIG. 4). In certain embodiments, a hub (not shown) may be coupled to the proximal end 425 of the sheath assembly 430. In other embodiments, the first lumen 120 or the second lumen 130, or both, may be configured with an elastomeric valve.

[0032] In some embodiments, a flexible atraumatic tip having at least one internal lumen and an open distal end is attached to the distal end 420 of the sheath assembly 430, where the first and second lumens 120, 130 of the sheath assembly 430 are in fluid communication with the internal lumen of the tip such that a continuous passageway is formed from the distal end 420 of the sheath assembly 430 to the distal end of the tip. In some embodiments, the tip comprises at least one of ethylene vinyl acetate (EVA), styrene-butadiene copolymer (SBC), synthetic rubber, elastomer, elastic material, material with a modulus of elasticity of about 1.6 ksi, and material with a yield strain of greater than 200%. In certain embodiments, the inner surface of the tip may be slightly tapered such that the inner diameter is larger at the proximal end than at the distal end of the tip. This creates a slight interference fit with the stylet 200 and the smallest diameter on the medical device 100. This creates a slight interference between the medical device 100 and the stylet 200 and helps seal off fluids or blood from entering the first and second lumens 120, 130. In other embodiments, the outer surface of the tip may also taper toward the distal end such that the outer diameter is larger at the proximal end than at the distal end. In certain embodiments, the distal end of the tip terminates in a leading edge having a radius that facilitates smooth insertion of the sheath assembly 430 into the patient's vasculature. The tip is highly resilient and does not exhibit permanent deformation (such as flaring or splitting).

[0033] FIG. 5A illustrates the sheath assembly 430 near an arteriotomy 440 in a patient. In FIG. 5A, apertures 505-509 are formed along the length of the sheath body 110. The apertures 505-509 terminate within the second lumen 130. The apertures 505-509 are formed along the length of the sheath body 110 to lie substantially along the bend of the sheath assembly 430 as it transitions from an insertion angle at the arteriotomy 440 to a position where the sheath is axial with the vessel 410. When the sheath assembly 430 is positioned within the vessel 410, at least some of the apertures 505-509 formed in the sheath body 110 are in direct fluid communication with the second lumen 130 to allow fluid flowing within the second lumen to exit the sheath body 110 and flow toward the end 414 of the vessel 410 as indicated by arrow C in FIG. 4.

[0034] FIG. 5B illustrates a cross-section of the sheath assembly 430 when positioned within a patient's vessel 410, taken along section line D-D' in FIG. 5A. The sheath assembly 430 includes a sheath body 110 having a first lumen 120 and a second lumen 130. An aperture 505 is formed in the sheath body 110 and is in direct fluid communication with the second lumen 130. Retraction of the stylet 200 from the second lumen 130 allows fluid within the vessel 410 to flow through the sheath assembly 430. For the portion 432 of the sheath assembly 430 located within the arteriotomy 440, fluid can flow from the second lumen 130 through the aperture 505 and back into the vessel 410, thereby maintaining the flow of fluid within the vessel 410. This is particularly palliative for patients suffering from vasospasm and the like. FIG. 5B also illustrates the passage of a medical device 550 within the first lumen 120. The stylet 200 is also positioned within the second lumen 130. Also shown in FIG. 5B is a central lumen 560 formed within the stylet 460, which is occupied by a guidewire 565. In certain embodiments, an internal stylet may be inserted into the central lumen 560 in place of a guidewire. In further embodiments, an internal stylet and a guidewire 565 may be used interchangeably within the central lumen 560. In some embodiments, the central lumen 560 is empty and terminates at a proximal end with an elastomeric valve or plug.

[0035] 5C-5D show the cross-sectional geometry of the sheath assembly 430 when positioned within a patient's vasculature, taken along section line D-D' in FIG. 5A. The sheath assembly 430 includes a first lumen 120 and a second lumen 130. A medical device 550 passes through the first lumen 120. The second lumen 130 has an aperture 505 for receiving the stylet 200. When the stylet 200 is moved longitudinally relative to the sheath body 110, the stylet 200 occludes the aperture 505. When the stylet 200 is removed, it exposes the aperture 505 so that blood can flow through the second lumen 130 and exit the sheath through the aperture 505. Alternatively, rather than using a stylet 200 to selectively occlude or open the aperture in the sheath body 110, an outer sheath or sleeve 201 is used. As shown in FIG. 5D, the outer sheath or sleeve 201 surrounds the sheath body 110 having a first lumen 120 through which a medical device 550 passes. The sheath body 110 includes apertures 505 that can be occluded or uncovered through relative longitudinal movement of the outer sheath or sleeve 201 relative to the sheath body 110. The outer sheath or sleeve 201 and the sheath body 110 are concentric. A gap exists between the outer sheath or sleeve 201 and the sheath body 110. In one example, the gap has a width of about 0.1 cm to 0.5 cm. As described above with respect to FIG. 5A, apertures 505-509 are formed along the length of the sheath body 110. For the configuration of FIG. 5D, the apertures 505-509 terminate within the first lumen 130. The apertures 505-509 are formed along the length of the sheath body 110 to lie substantially along the bend as the sheath assembly 430 transitions from the insertion angle at the arteriotomy 440 to a position where the sheath is axial with the vessel 410.When the sheath assembly 430 is positioned within the vessel 410, at least some of the apertures 505-509 formed in the sheath body 110 are in direct fluid communication with the second lumen 130 to allow fluid flowing within the second lumen to exit the sheath body 110 and flow toward the end 414 of the vessel 410 as indicated by arrow C in FIG. 4. In some examples, the outer sheath or sleeve 201 surrounds the sheath body 110 and extends distal to the bend in the sheath assembly 430. The outer sheath or sleeve 201 may surround the sheath body 110 and extend proximal to the bend in the sheath assembly 430. In one compatible configuration, the outer sheath or sleeve 201 is introduced into the patient's body as part of the sheath assembly 430, and the outer sheath or sleeve 201 completely covers the apertures 505-509 formed along the length of the sheath body 110. After insertion, and depending on the limb perfusion observed or desired, the clinician or other care provider selectively opens several of the apertures 505-509 by moving the outer sheath or sleeve 201. When an aperture 505 is opened, i.e., when the outer sheath or sleeve 201 is slid proximally so that it no longer covers the aperture 505, blood flows from a location upstream from the sheath assembly, through the distal end of the sheath assembly, through the open aperture 505, and into the portion of the artery distal to the arteriotomy.

[0036] FIG. 6 illustrates the sheath assembly 430 of FIGS. 5A and 5B inserted into an arteriotomy 440 of a patient. When the sheath assembly 430 is inserted into position, the distal end 420 of the sheath assembly 430 is axially aligned with the vessel 410. When the sheath assembly 430 is inserted as illustrated in FIG. 6, the apertures 505-508 are located within the vessel 410, while the apertures 509-510 are external to the vessel 410. Thus, in the absence of a stylet in the second lumen 130, the apertures 505-508 allow the second lumen 130 and the vessel 410 to be in fluid communication with each other. FIG. 6 also illustrates a medical device 550 inserted into the first lumen 120 and a stylet 200 inserted into the second lumen 130. Here, the stylet 200 is fully inserted into the second lumen 130. The stylet 200 plugs the second lumen 130 to prevent fluid from entering the distal end 420 of the second lumen 130, thereby preventing fluid communication through the apertures 505-508 from the second lumen 130 to the exterior of the sheath assembly 430. This configuration represents an insertion configuration in which it is desired that there is no fluid bypass.

[0037] 7 illustrates the sheath assembly 430 as depicted in FIG. 6 with the stylet 200 partially retracted from the second lumen 130 when fluid bypass through the sheath assembly 430 is desired. The stylet 200 is partially retracted in that the apertures 505-508 formed in the sheath body 110 (as depicted in FIG. 7) are uncovered, while the remaining apertures 509-510 in the sheath body 110 remain covered by the stylet 200. Retracting the stylet 200 past at least one of the apertures allows fluid to flow from the distal end 420 of the sheath assembly 430 (the distal end 420 of the sheath assembly 430, which is within the distal portion 412 of the vessel 410) through the second lumen 130, through the uncovered apertures 505-508, and to the end 414 of the vessel 410. Arrows E and E' in FIG. 7 indicate such fluid flow. This configuration represents a situation where the sheath completely fills the vessel 410 (e.g., a patient with vasospasm), allowing blood perfusion to the limb. The stylet 200 is shown exposing apertures 505-508 within the vessel 410 to allow fluid flow, but not exposing apertures 509-510 outside the vessel 410 to prevent fluid flow into the subcutaneous tissue 405 and into the insertion track. It is critical to determine the correct position of the stylet 200 relative to the sheath assembly 430 to allow flow within the vessel 410, while preventing fluid from entering the subcutaneous tissue and the insertion track. Methods for determining this position are discussed in a later section.

[0038] In any of the foregoing embodiments, as the stylet 200 is retracted, only one aperture is opened at a time near the arteriotomy 440, so each aperture should provide a cross-sectional area similar to that of the second lumen 130. This allows for optimal distal perfusion without causing a build-up of pressure within the vessel 410. Additionally, although any shape of aperture may be used, the shapes used in the foregoing embodiments are selected such that the stylet 200 can be safely advanced across a bend near the arteriotomy 440 without risk of the stylet 200 exiting through any one of the apertures.

[0039] Although a limited number of apertures are illustrated in Figures 5A, 6, and 7, any number of apertures may be formed along the length of the sheath body 110 to connect the exterior surface 118 of the sheath body 110 with the second lumen 130. In some embodiments, multiple apertures are formed along a given length of the sheath body 110 to minimize the risk of an aperture becoming blocked during use. In other embodiments, a continuous channel along the length of the sheath body 110 is used instead of multiple discrete apertures. In further embodiments, the apertures are arranged according to a distribution pattern along the length of the sheath body 110 to minimize the risk of blockage due to an obstruction in the vessel 410. Such distribution patterns include, but are not limited to, linear, logarithmic, step-wise, etc.

[0040] FIG. 8A illustrates a cross-section of a stylet 800 according to one embodiment of the present disclosure. Stylet 800 is similar to stylet 200 in FIG. 2, except that in FIG. 8A, stylet body 810 has a central lumen 820 running through a portion of the length of stylet 800. Central lumen 820 is similar to central lumen 560 shown in FIG. 5B. A side view of stylet 800 is shown in FIG. 8B, showing a skive 830 formed at the distal end 805 of stylet 800. FIG. 8B also shows the fluid path within stylet 800, running from skive 830 through central lumen 820 and terminating at the proximal end 840 of stylet 800. Central lumen 820 terminates in an opening 850 at the proximal end 840 of stylet 800. Distal end 805 of stylet 800 is plugged. In certain embodiments, the distal end 805 may be open, for example to allow for the passage of a guidewire. The skive 830 provides fluid communication from the exterior of the stylet 800 to the second lumen 130 near the skive 830 when the stylet 800 is used in conjunction with the sheath assembly 430. FIG. 8C shows an isometric view of the skive 830 at the distal end 805 of the stylet 800. As seen in FIGS. 8A-8C, the central lumen 820 and the skive 830 form a passageway for fluid to flow from the skive 830 to the proximal end (not shown) of the stylet 800. In the embodiment depicted in FIGS. 8B and 8C, the central lumen 820 does not extend beyond the skive 830, so that the passageway 800 terminates at the distal end 805 of the stylet 800. In another embodiment, markings are formed on the stylet body 810 toward the proximal end 840 of the stylet 800 to indicate the position of the stylet relative to the distal tip 420 of the sheath assembly 430 or relative to the apertures 505-510 formed in the sheath body 110. This allows for easy determination of the position of the arteriotomy relative to the stylet.

[0041] In some embodiments, the proximal end 425 of the sheath assembly 430 may be coupled to a hub, as known in the art. The hub has an internal conduit that is in fluid communication with the first and second lumens 120, 130 of the sheath assembly 430 when the hub is coupled to the proximal end 425 of the sheath assembly 430. In other embodiments, the first lumen 120 may be coupled to the first hub and the second lumen may be coupled to the second hub. In this configuration, the medical device 550 is introduced into the sheath assembly 430 through the first hub and the stylet 800 is inserted into the sheath assembly through the second hub. In some embodiments, the first and second hubs are integral to one another. In any of the foregoing embodiments, the hub is provided with structure, such as, but not limited to, suture holes or wings, to facilitate attachment to a patient.

[0042] In some embodiments, insertion and withdrawal of the stylet 800 to selectively open and close the second lumen 130 is accomplished using a ratchet mechanism attached to the proximal end 425 of the sheath assembly 430. Such a ratchet mechanism ensures that movement of the stylet 800 toward the proximal end 425 of the sheath assembly 430 is controlled in standard increments.

[0043] The use of the sheath assembly 430 for selective fluid bypass, as described with respect to Figures 4, 5A, 6, and 7, will now be described with respect to Figures 9A and 9B. A physician using the sheath assembly 430 with a stylet 800 can determine precise positioning of the sheath assembly 430 and the arteriotomy 440 to enable fluid bypass through the second lumen 130. This is indicated by the presence of fluid at the opening 850 at the proximal end 840 of the stylet 800. In Figures 9A and 9B, the sheath assembly 430 is shown in a straightened state for illustrative purposes. Thus, the arteriotomy 440 is shown as a diagonal line such that the sheath assembly 430 to the left of the line 440 is within the target vessel 410 and the sheath assembly 430 to the right of the line 440 is outside the target vessel 410.

[0044] Figure 9A illustrates a cross-section of the sheath assembly 430 within a target vessel 410 (not shown) in a first configuration. Figure 9A shows the first and second lumens 120, 130 of the sheath, as well as apertures 932-935 in the sheath body that are in fluid communication with the second lumen 130. In Figure 9A, the stylet 800 is partially retracted, where apertures 932-934 are inside the vessel 410 (located to the left of the arteriotomy 440) and aperture 935 is outside the vessel 410 (located to the right of the arteriotomy 440).

[0045] The skive 830 of the stylet 800 is in fluid communication with the central lumen 820. The length of the skive 830 is less than the distance between the apertures 932-935 of the sheath assembly 430. FIG. 9A shows the stylet 800 positioned such that blood originating from the vessel 410 and entering through the distal tip 420 of the sheath assembly 430 can exit through the first and second apertures 932-933, with the distal tip 805 of the stylet 800 blocking blood flow through the remainder of the second lumen 130 of the sheath assembly 430. As noted with respect to FIGS. 8A-8C, the stylet 800 has a plugged distal tip 805 that prevents fluid communication from the distal end 805 of the stylet 800 to the skive 830. Therefore, blood flowing from the distal end 420 of the second lumen 130 within the sheath assembly 430 must exit the second lumen 130 through apertures 932-933 and re-enter the stylet 800 through the skive 830 and flow into the central lumen 820.

[0046] A third aperture 934 located within the length of the skive 830 resides within the target vessel 410. This provides fluid communication from the vessel 410, through the aperture 435, into the skived area 830 (see arrow F), and down the central lumen 820 of the stylet 800. Pressurized blood flow in the vessel 410 causes visible, pulsatile bleeding to exit the proximal end 840 of the stylet 800. This blood flow is visible at the opening 850 of the central lumen 820 at the proximal end 840 of the stylet 800. The position of the skive 830 also terminates before the fourth aperture 935, which entails that the body 810 of the stylet 800 blocks fluid communication through the aperture 935. In this configuration, the presence of blood flow on the proximal end 840 of the stylet 800 indicates that there is at least one aperture near the distal end 805 of the stylet 800 within the vessel 410 and that the stylet 800 can be further retracted.

[0047] 9B illustrates a cross-section of the sheath assembly 430 within the target vessel 410 in a second configuration subsequent to the first configuration as described above. In the second configuration, the stylet 800 is positioned within the sheath assembly 430 such that blood entering through the distal tip 420 of the sheath assembly 430 can exit through the first, second, and third apertures 932-934, with the distal end 805 of the stylet 800 blocking flow through the remainder of the second lumen 130 of the sheath assembly 430. A fourth aperture 935, located outside the vessel 410 (to the right of the arteriotomy 440), resides within the length of the skive 830. This prevents fluid communication from the vessel 410, through the second lumen 130, into the skived area 830, and down the central lumen 820 of the stylet 800. The pressurized blood flow in the vessel 410 no longer causes pulsatile bleeding out of the exit port 850 at the proximal end 840 of the stylet 800. In this configuration, the absence of blood flow at the proximal end 840 of the stylet 800 indicates the absence of an aperture near the distal end 805 of the stylet 800 within the target vessel 410.

[0048] The transition from the first configuration in FIG. 9A (with visible blood flow exiting outlet 850 at the proximal end 840 of the stylet 800) to the second configuration in FIG. 9B (with no blood flow exiting outlet 850 at the proximal end 840 of the stylet 800) indicates that the stylet 800 is positioned in an ideal position relative to the sheath assembly 430 and arteriotomy 440 such that blood is bypassed through the sheath assembly 430.

[0049] 10 illustrates an exemplary method 1000 of using a continuous perfusion sheath assembly 430. Such an assembly includes a sheath body 110 with a first lumen 120 and a second lumen 130, where the first lumen 120 provides a passageway for a medical device and the second lumen 130 is loaded with a stylet 800 for selectively opening and closing the second lumen for blood bypass through the sheath assembly 430. The exemplary method 1000 may be performed with the continuous perfusion sheath assembly 430 or any other suitable sheath assembly tool. The method 1000 begins at step S1010, where the sheath assembly 430 is positioned within a target vessel with the physician attempting to create a blood bypass through the sheath (e.g., in a patient experiencing vasospasm). In step S1010, the physician partially retracts the stylet 800 from the sheath assembly 430. This is done by pulling the distal end 840 of the stylet 800 towards the distal end 425 of the sheath assembly 430 while ensuring that the sheath assembly 430 remains in position within the patient's arteriotomy.

[0050] In step 1020, the physician stops retracting the stylet 800 and checks the opening 850 at the distal end 840 of the stylet 800 for visible and pulsatile bleeding. If signs of flowing blood are present at the opening 850, i.e., decision step S1020 is "yes," the physician repeats S1010 to continue partially retracting the stylet 800 from the sheath assembly 430. This is the situation described with respect to the first configuration of FIG. 9A. If blood flow from the opening 850 at the distal end 840 of the stylet 800 has stopped, i.e., decision step S1020 is "no" (as in the second configuration depicted in FIG. 9B), the method proceeds to step S1030 where the physician secures or locks the position of the partially retracted stylet 800 relative to the sheath assembly 430. Fluid bypass is then achieved, and the method ends in step S1040.

[0051] In light of the above, it will be appreciated by those skilled in the art that the present disclosure provides a means for allowing blood to flow through a constricted blood vessel during the course of a medical procedure, thereby avoiding the need to employ other surgical methods (such as femoral-femoral artery bypass), which would increase the complexity and expense of the medical procedure.

[0052] The foregoing is merely illustrative of the principles of the present disclosure, and the systems, methods, and devices of the present invention may be practiced in other ways than those described herein, which are presented for purposes of illustration and not limitation. It should be understood that the systems, methods, and devices disclosed herein, although shown for use in a percutaneous heart pump, may also be applied to systems, methods, and devices for other implantable heart pumps or implantable cardiac assist devices.

[0053] Variations and modifications will occur to those skilled in the art after reviewing this disclosure. The various features described or illustrated above, including components thereof, may be combined or integrated into other systems. Additionally, certain features may be omitted or not implemented. The various embodiments described or illustrated above may be combined in any manner.

[0054] Examples of changes, substitutions, and alterations are ascertainable by one of ordinary skill in the art and can be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made a part of this application.

[0055] FIG. 11 illustrates an exemplary method 1100 for providing adequate limb perfusion while using a sheath assembly. In an initial procedure, a clinical practitioner or other care provider creates a puncture through the patient's skin and percutaneously inserts a sheath through the puncture site and through an arteriotomy into the patient's artery (steps 1102, 1104). Additional steps may be performed by the clinical practitioner or care provider between the puncture and arteriotomy and the insertion of the sheath through the puncture and arteriotomy. For example, the clinical practitioner or other care provider may use a guidewire and may use successive dilators to gradually enlarge both the puncture and the arteriotomy sufficiently to accept a sheath, which may be an introducer sheath or a repositioning sheath. The sheath is advanced until its distal end is positioned within the artery and the proximal end of the sheath is positioned outside the patient's body. After placing the sheath, the physician opens a pathway through the sheath to allow blood to flow from one side of the sheath to the other, i.e., to flow from a location upstream from the arteriotomy, past (e.g., around or through) the sheath, and to reach the patient's downstream vasculature downstream from the arteriotomy. In one example, the pathway allows blood to flow from a portion of the artery upstream from the arteriotomy to a portion of the artery downstream from the arteriotomy (and downstream from the sheath), thereby achieving limb perfusion. Opening a pathway through the sheath to allow blood to flow past the sheath within the artery may be performed by using any of the sheaths described herein, for example, with respect to Figures 1-9 and 12 (selectively opening an aperture in the sheath by retracting a device occluding the aperture in the sheath); Figures 13-14 (expanding a distal portion of the sheath to expand the diameter of the artery); Figures 15-16 (connecting a blood flow channel through the sheath to a second sheath inserted into the artery downstream from the arteriotomy for the first sheath); or Figures 17-19 (inflating a balloon attached to the outer surface of the sheath, thereby expanding the arterial diameter).

[0056] A clinical practitioner or other care provider checks whether limb perfusion is adequate (e.g., step 1108). For example, a physician may periodically check the capillary refill of the patient's limb distal to the arteriotomy. If the clinical practitioner or other care provider determines that limb perfusion is adequate (step 1108), no action is required from the clinical practitioner or other care provider to further open the blood flow path (step 1112). Otherwise, if the clinical practitioner or other care provider determines that limb perfusion is inadequate (step 1108), then to improve limb perfusion, the clinical practitioner or other care provider steepens the pathway through the sheath (step 1110) to allow more blood to flow from the portion of the artery upstream from the arteriotomy to the portion of the artery downstream from the arteriotomy. Opening an initial pathway through the sheath to allow blood to flow from the upstream side to the downstream side of the sheath, as well as widening or further opening that initial pathway, may similarly be accomplished by using any of the sheaths described herein with respect to Figures 1-9 and 12 (further retracting the device occluding the aperture in the sheath to open more sheath); Figures 13-14 (further expanding the distal portion of the sheath to further expand the diameter of the artery); Figures 15-16 (fitting a connection between the blood flow channel through the sheath and a second sheath inserted in the artery distal to the arteriotomy for the first sheath to increase the flow rate of the second sheath); or Figures 17-19 (further inflating a balloon attached to the exterior surface of the sheath to further expand the artery diameter). The clinician or other care provider again checks for adequate limb perfusion (e.g., step 1108). At least one benefit of method 1100 is the ability to address cases where there is insufficient blood flow from the arteriotomy upstream to downstream of the arteriotomy to maintain adequate limb perfusion. At least an additional benefit of method 1100 is the ability to adjust the amount of blood that flows from a location upstream of the arteriotomy past (e.g., around or through) the sheath and reaches the patient's downstream vasculature downstream of the arteriotomy based on the particular circumstances of the patient and procedure.

[0057] FIG. 12 illustrates an exemplary method 1200 for providing limb perfusion using a sheath assembly by retracting a device occluding the sheath, thereby encouraging blood flow downstream of the sheath. In an initial procedure, a clinical practitioner or other care provider creates a puncture through the patient's skin and percutaneously inserts a sheath through the puncture site and through an arteriotomy into the patient's artery (steps 1202, 1204). Additional steps may be performed by the clinical practitioner or care provider between the puncture and arteriotomy and the insertion of the sheath through the puncture and arteriotomy. The sheath is advanced until its distal end is positioned within the artery and the proximal end of the sheath is positioned outside the patient's body. At this point, the sheath may be used to introduce a medical device through the sheath and into the patient's artery. The medical device is activated. During insertion or activation of the medical device, the clinical practitioner or care provider may first check for adequate limb perfusion. If the clinical practitioner or care provider makes an initial determination that limb perfusion is inadequate, the clinical practitioner or care provider retracts the sheath occluding device (step 1206), thereby opening a pathway through the sheath to allow blood to flow from upstream the arteriotomy to downstream the arteriotomy. In one example, the clinical practitioner or care provider may retract the sheath occluding device a default first amount regardless of the level of limb perfusion initially observed. For example, as described above with respect to FIGS. 1-9, the sheath may have apertures, slots, or both along its length. In one example, as described above with respect to FIGS. 1-9, the occluding device is a stylet that can be selectively moved through the lumen of the sheath. In another example, the occluding device is an outer sheath or sleeve that surrounds the sheath, as described above with respect to at least FIG. 5D. The pathway opened by retracting the occluding device allows blood to flow from a portion of the artery upstream the arteriotomy to a portion of the artery downstream the arteriotomy to provide limb perfusion.

[0058] Periodically after the initial check, the clinical practitioner or other care provider checks whether limb perfusion is adequate (e.g., step 1208). For example, a physician may check the capillary refill of the patient's limb at a position distal to the arteriotomy. If the clinical practitioner or other care provider determines that limb perfusion is adequate (step 1208), no action is required from the clinical practitioner or other care provider to further open the blood flow path (step 1212). Otherwise, if the clinical practitioner or other care provider determines that limb perfusion is inadequate (step 1208), then to improve limb perfusion, the clinical practitioner or other care provider widens the pathway through the sheath (step 1210) to allow more blood to flow from the portion of the artery upstream from the arteriotomy to the portion of the artery downstream from the arteriotomy. For example, if a stylet is being used to selectively occlude or uncover apertures in the sheath, the clinician or other care provider may retract the stylet further, i.e., retract the stylet more to uncover more of the apertures in the sheath, thereby increasing the cross-sectional area of ​​the open blood flow path. In another example, if an outer sleeve is being used to selectively occlude or uncover apertures in the sheath, the clinician or other care provider may retract the outer sleeve further to uncover more of the apertures in the sheath, thereby increasing the cross-sectional area of ​​the open blood flow path. Similar to the advantages of method 1100, at least some of the advantages of method 1200 are the ability to adjust the amount of blood passed from upstream of the arteriotomy to downstream of the arteriotomy based on the particular circumstances of the patient and the procedure.

[0059] In one example, steps 1202-1206 of method 1200 may be informed by an existing arteriotomy reference point. In the absence of an existing arteriotomy reference point, the clinical practitioner or other care provider may adjust the amount of pullback of the sheath-occluding device by knowing the geometry of the sheath-occluding device and by monitoring blood flow at the access site as described with respect to FIGS. 9A-B. In the presence of existing arteriotomy data, the clinical practitioner or other care provider may rely on an established arteriotomy reference point that was established prior to insertion of the sheath or prior to insertion of the sheath-occluding device and indicates that the arteriotomy is at a known and fixed distance from the patient's skin. Thus, the clinical practitioner or other care provider may compare the arteriotomy data to the length of the sheath-occluding device to determine how to move the sheath-occluding device relative to the sheath to obtain the desired flow. An exemplary method for establishing an arteriotomy reference point is described below with reference to FIG. 21.

[0060] FIG. 13 shows an exemplary diagram of a sheath with a distal expandable portion, according to one embodiment of the present disclosure. The sheath 1306 is introduced through the skin 1302 and into the patient's artery 1304. For example, the sheath 1306 is introduced using steps similar to steps 1102-1104 of method 1100. A catheter 1308 runs through the sheath and into the artery. The sheath 1306 includes a distal expandable portion 1310. In the example shown in FIG. 13, the distal expandable portion 1310 is a mesh. A clinician or other caregiver expands the distal expandable portion 1310 in situ to open a pathway through the sheath 1306 to allow blood to flow from upstream the arteriotomy to downstream the arteriotomy (see, for example, step 1106 of method 1100 in FIG. 11). As shown in the example of FIG. 13, when the distal expandable portion 1310 is expanded, it creates a pathway 1312 for blood to flow from a location in the artery upstream from the arteriotomy, through the porous distal expandable portion 1310 of the sheath, and to a location in the artery downstream from the arteriotomy.

[0061] The distal expandable portion 1310 has a cross-section that varies along its length when expanded. For example, the cross-section of the upstream end of the distal expandable portion 1310 is larger than the cross-section of the downstream end of the distal expandable portion 1310 when expanded. In one example, the cross-section of the distal expandable portion is circular along the length of the distal expandable portion. In one example, the distal expandable portion is a surface of revolution formed by an S-shaped curve. In one example, the distal expandable portion is made of a porous material, such as polytetrafluoroethylene (PTFE). In another example, the distal expandable portion is made of a mesh with openings or windows between the mesh elements. In some examples, the distal expandable portion 1310 may be woven or laser cut. In another example, the distal expandable portion 1310 may be a stent attached to the distal end of the sheath 1306. In one example, the distal expandable portion 1310 may be biased to an open state to have a resting state with a larger diameter and may be expanded by pulling back a portion of the sheath 1306 constraining the distal expandable portion 1310. Alternatively, in another example, the distal expandable portion 1310 is biased to a closed state, expanded in situ with a balloon, and held in the expanded configuration by a mechanism, such as, for example, friction between the fabric and the expandable end portion 1310, or a mechanical locking mechanism. In other examples, alternative expansion mechanisms besides a balloon are used, including any expansion mechanisms used for stents.

[0062] The expanded shape of the distal expandable portion 1310 is configured to open a pathway through the sheath 1306 to allow blood to flow from upstream of the arteriotomy to downstream of the arteriotomy. For example, the shape of the distal expandable portion may be an S-shape with a first bend and a second bend. The respective curvatures of the first and second bends, the slope of the segment between the first and second bends, or a combination of the curvature and slope are configured to expand the diameter of the vessel upstream of the arteriotomy over a relatively small longitudinal distance. In some embodiments, the slope of the segment between the first and second bends is about 20-80 degrees, about 30-60 degrees, or about 40 or 50 degrees.

[0063] The length of the distal expandable portion of the sheath relative to the length of the sheath may vary. In one example, the length of the distal expandable portion of the sheath is fixed prior to insertion. In one example where the length of the expandable portion of the sheath is fixed prior to insertion, the length of the distal expandable portion of the sheath is selected to be less than half the length of the sheath. In another example where the length of the expandable portion of the sheath is fixed prior to insertion, the length of the distal expandable portion of the sheath is selected to be less than one-quarter the length of the sheath. In another example, the length of the distal expandable portion of the sheath is varied in situ. For example, a clinician or other caregiver may select the length of the distal expandable portion of the sheath that best fits the patient's geometry by selectively unsheathing only a portion of the distal expandable portion of the sheath.

[0064] FIG. 14 illustrates an exemplary method 1400 for providing adequate limb perfusion using the sheath of FIG. 13. In an initial procedure, a clinical practitioner or other care provider creates a puncture through the patient's skin and percutaneously inserts a sheath through the puncture site and through an arteriotomy into the patient's artery (steps 1402, 1404). Additional steps may be performed by the clinical practitioner or care provider between the puncture and arteriotomy and the insertion of the sheath through the puncture and arteriotomy. The sheath is advanced until its distal end is positioned within the artery and the proximal end of the sheath is positioned outside the patient's body. In one example, after insertion of the medical device and initial actuation of the medical device, the clinical practitioner or other care provider preemptively expands a distal portion of the sheath to allow blood to flow from upstream of the arteriotomy through the distal expandable end of the sheath and downstream of the arteriotomy. In another example, the clinical practitioner or other care provider first checks whether limb perfusion is adequate (step 1408). As described above with respect to at least FIG. 13, expansion of the distal expandable portion of the sheath may be accomplished via balloon expansion; withdrawing a biased open device from the sheath; and / or any other suitable mechanism, including any expansion mechanism used to deploy a stent. As a result, the expandable distal portion of the sheath has an expanded diameter that is larger than the proximal portion of the sheath and forces expansion of the artery. If, after checking whether limb perfusion is adequate, the clinical practitioner or other care provider determines that limb perfusion is adequate (step 1408), no action is required from the clinical practitioner or other care provider to further open the blood flow path (step 1410). Otherwise, if the clinician or other care provider determines that limb perfusion is inadequate (step 1408), the clinician or other care provider further adjusts or expands the distal expandable portion of the sheath (step 1406) to further expand the diameter of the artery in order to increase the size of the flow path for blood to flow from upstream to downstream of the arteriotomy and improve distal perfusion. A physician may periodically check the capillary refill of the patient's limb distal to the arteriotomy.

[0065] In one example, if the clinician or other care provider is using a balloon to expand the distal expandable portion, the clinician or other care provider further inflates the balloon to further increase the artery diameter. In another example, the clinician or other care provider expands a longer segment of the distal expandable portion of the sheath to increase blood flow from a location upstream from the arteriotomy, past (e.g., around or through) the sheath to the patient's downstream vasculature downstream from the arteriotomy. In another example, the clinician or other care provider selectively adjusts the expanded shape of the expandable distal portion to increase the size of the blood flow path and increase blood flow from a location upstream from the arteriotomy, past (e.g., around or through) the sheath to the patient's downstream vasculature downstream from the arteriotomy.

[0066] In one example, a clinician or other care provider administers an anticoagulant during the course of the procedure. The anticoagulant prevents blood from clotting within the pores or mesh openings of the distal expandable portion and occluding the distal expandable portion. The anticoagulant also minimizes the risk of blood clots being released into the patient's bloodstream and posing a health risk. An advantage of at least some of the methods 1400 and sheaths illustrated with respect to Figures 13 and 14 is the ability to selectively expand or contract the distal expandable portion of the sheath to accommodate different patient geometries or arterial conditions.

[0067] FIG. 15 illustrates an exemplary isometric view of a sheath assembly with two sheaths according to one embodiment of the present disclosure. FIG. 15 is similar to FIG. 4 of the present disclosure, but includes a second sheath 1502. The sheath 1502 is connected at a first end to the first sheath assembly 430 such that blood can flow from the sheath assembly 430 into the sheath 1502. The sheath assembly 430 includes a lumen through which blood can flow from a distal end of the sheath assembly 430 to a more proximal location. For example, the lumen may be a lumen located within the sheath body, as described with respect to FIGS. 1-7, or may be a lumen formed between the sheath body and the outer sleeve. In another example, the lumen may be formed as a side liger channel along the sheath body. Blood flows from a location upstream from the arteriotomy, through the sheath assembly 430, and into the sheath 1502. A second end of the sheath 1502 pierces the patient's skin at a location 1504 distal to the first skin puncture 450 and penetrates the patient's artery at a second arteriotomy site 1506 downstream from the first arteriotomy. Thus, blood can flow from the area upstream from the first arteriotomy, through the sheath assembly and second sheath, into the second arteriotomy, and downstream from the second arteriotomy.

[0068] In one example, the length of the lumen is equal to the length of the sheath body. In another example, the length of the lumen is less than the length of the sheath body. The first end of the second sheath 1502 connects to the lumen anywhere along the length of the lumen such that blood can flow from the lumen to the first end of the second sheath 1502. In one example, the first end of the second sheath 1502 connects to the proximal end of the lumen. In another example, the first end of the second sheath 1502 connects to the lumen anywhere along the length of the lumen. In one example, the proximal end of the lumen is external to the patient's skin such that a clinical practitioner or other care provider can easily connect the first end of the second sheath 1502 to the end of the lumen. In another example, the proximal end of the lumen is located under the patient's skin such that a clinical practitioner or other care provider can slide the first end of the second sheath 1502 into the first sheath to connect the first end of the second sheath 1502 to the lumen at the proximal end.

[0069] FIG. 16 illustrates an exemplary method for providing adequate limb perfusion using the sheath assembly of FIG. 15. In an initial procedure, a clinical practitioner or other care provider creates a first puncture through the patient's skin and percutaneously inserts a first sheath through the first puncture site and through the arteriotomy into the patient's artery (steps 1602, 1606). Additional steps may be performed by the clinical practitioner or care provider between the first puncture and first arteriotomy and the insertion of the first sheath through the first puncture and first arteriotomy, for example as described above with respect to FIG. 14. The sheath is advanced until its distal end is positioned within the artery and the proximal end of the sheath is positioned outside the patient's body. In addition, the clinical practitioner or other care provider creates a second puncture through the patient's skin and percutaneously inserts a second sheath through the second puncture site and through the arteriotomy into the patient's artery (steps 1604, 1608). The second sheath is similarly advanced until its distal end is positioned within the artery and the proximal end of the second sheath is positioned outside the patient's body. In one example, the insertion of the first and second sheaths may be performed in parallel. In another example, the insertion of the first and second sheaths may be performed sequentially.

[0070] After an initial check for limb perfusion accuracy, or as a preventative or default measure, the clinical practitioner or other care provider then connects the first sheath to the second sheath (step 1610) to create a blood flow channel between a location upstream from the first arteriotomy and a location downstream from the second arteriotomy. In one example, the clinical practitioner or other care provider selects a relatively short longitudinal distance between the first and second arteriotomy. A relatively short distance between the first and second arteriotomy may be beneficial to minimize fluid loss and to minimize the risk of blood clots or sheath obstruction. For example, the distance between the first and second arteriotomy may be about 5 cm to 20 cm, about 10 cm to 15 cm, or about 12 cm to about 14 cm. The distance between the first and second arteriotomy may vary depending on the patient geometry and the characteristics of the procedure. For example, a patient in whom venous access is more difficult may require a shorter distance between the first and second arteriotomy compared to a patient in whom venous access is easier and closer to the skin surface. In another example, a patient may have a longer or shorter limb and may require a longer or shorter distance, respectively, for the second sheath to access the artery at a suitable location downstream from the first arteriotomy. The clinical personnel or other care provider periodically checks for adequate limb perfusion distal to the first arteriotomy (step 1612). For example, as described above with respect to FIG. 11, this may involve checking for capillary reflexes and / or periodically checking skin color in the limb.

[0071] If limb perfusion is adequate, no action is required from the clinical practitioner or other care provider to further open the blood flow path. Alternatively, if limb perfusion is not adequate, the clinical practitioner or other care provider adjusts parameters of the blood flow channel between a first location upstream from the first arteriotomy and a second location downstream from the second arteriotomy (step 1616). In one example, the connection between the lumen through which blood passes from upstream from the arteriotomy to downstream from the arteriotomy (as described with respect to FIG. 15 ) and the second sheath 1502 includes a valve. In this example, the clinical practitioner or other care provider may adjust the amount of flow passing from the lumen to the second sheath 1502 by selectively opening, i.e., further opening, the valve to increase the flow of blood passing through the first sheath, into the second sheath, and into the artery downstream from the first arteriotomy. In another example, a clinical practitioner or other care provider may increase the diameter of the lumen and / or increase the diameter of the second sheath 1502. For example, a clinical practitioner or other care provider may replace the existing second sheath 1502 with a new sheath 1502 having a larger diameter. A clinical practitioner or other care provider may also further open flow through the lumen by increasing the cross-section of the lumen. For example, as described with respect to FIGS. 1-9, a clinical practitioner or other care provider may selectively increase the cross-section of the lumen by selectively uncovering additional apertures and increasing blood flow from a location upstream from the arteriotomy through the lumen, into the second sheath, and to a location downstream from the arteriotomy.

[0072] At least one benefit of the sheath of Figure 15 and the associated method of Figure 16 is that it is possible to open a blood flow path between a location upstream from the first arteriotomy and a location downstream from the first arteriotomy (e.g., a second arteriotomy) while requiring only one additional "stick point" or skin puncture 1504 - making use of the sheath of Figure 15 and the method of Figure 16 safer and simpler than procedures that require additional stick points and more complex equipment, such as ECMO. Similarly, at least one benefit of the sheath of Figure 15 compared to a femoral-femoral bypass is that it is possible to open a blood flow path between a location upstream from the first arteriotomy and a location downstream from the first arteriotomy (e.g., a second arteriotomy) while requiring only one additional "stick point" or skin puncture 1504.

[0073] FIG. 17 shows an exemplary diagram of a sheath with an expandable balloon on its outer surface to promote downstream perfusion of the patient's vasculature. The sheath 1702 is inserted through the patient's skin 1704 and into the patient's artery 1708 via an arteriotomy 1706. The sheath 1702 includes a balloon 1714 along at least a portion of the length of the sheath and on the outer surface of the sheath. The balloon 1714, when inflated, moves the outer surface of the sheath 1702 away from the wall 1712 of the artery by locally expanding the artery to a larger diameter. The balloon 1714 is sized and shaped to allow blood flow within the artery, illustrated by arrow 1716 in FIG. 7, from a location upstream from the arteriotomy to a location downstream from the arteriotomy. An exemplary shape of the balloon 1714 is shown and described below with respect to FIGS. 18A-B. In one example, the length of the balloon is less than the length of the sheath 1702. In another example, the length of the balloon is less than half the length of the sheath 1702. In one example, the balloon may form a cylindrical void upon expansion. Alternatively, the balloon may form a wedge void upon expansion, for example, as shown and described below with respect to FIG. 18. Alternatively, in another example, the balloon may form a torus. In another example, the balloon 1714 may be any shape that forms a channel along the length of the balloon through which fluid can flow.

[0074] The balloon 1714 is inflated by inserting an inflation fluid through an inflation lumen connected to the balloon 1714. Such an inflation lumen runs along at least a portion of the length of the sheath body and has an opening into the balloon cavity located on the exterior surface of the sheath. In one example, the inflation lumen is a side lumen attached to the exterior surface of the sheath body along the length of the inflation lumen. In another example, the inflation lumen is a lumen located within the sheath body but communicates with the exterior of the sheath body through an aperture in the sheath through which the balloon can be inflated and deployed outside the sheath body. In one example, the balloon is stored inside the inflation lumen and deployed when inflation fluid is inserted through the inflation lumen. In another example, the balloon is stored at the distal end of the inflation lumen and deployed when inflation fluid is inserted through the inflation lumen.

[0075] 18A-B show an exemplary cross-sectional view of a sheath 1804 with an expandable balloon 1806 on the outer surface of the sheath according to one embodiment of the present disclosure. FIGS. 18A-B show an inflated balloon 1806. In FIG. 18A, the balloon 1806 is shaped with a relatively triangular cross-section and spans less than 360 degrees around the sheath 1804, instead leaving a gap 1808 between the sheath 1804 and the vessel wall 1802 where the balloon is not located. Similarly, in FIG. 18B, the balloon 1806 is expanded and leaves gaps 1808 and 1810 between the sheath and the vessel wall. Depending on the inflation level or shape of the balloon 1806 (shown as a torus in FIG. 18B), blood can flow through the gap 1808, the gap 1810, or a combination of both. In one example, the type of balloon is selected based on the patient geometry and the characteristics of the procedure. At least one advantage of using the balloon discussed with respect to Figures 17 and 18A-B is that it can locally and temporarily dilate the vessel to open a flow path for blood to flow from a location upstream of the arteriotomy to a location downstream of the arteriotomy.

[0076] FIG. 19 illustrates an exemplary method for providing adequate limb perfusion using the sheath of FIG. 17 or FIG. 18A-B. Process 1900 begins at step 1902 where a clinical practitioner or other care provider inserts a sheath through the patient's skin. In step 1904, the clinical practitioner or other care provider inserts the sheath through an arteriotomy and into the patient's artery. In step 1906, the clinical practitioner or other care provider inflates a balloon to open a pathway between the sheath and the arterial wall. The clinical practitioner or other care provider checks whether limb perfusion is adequate (step 1908). If the clinical practitioner or other care provider determines that limb perfusion is adequate (step 1908), no action is required from the clinical practitioner or other care provider to further open the blood flow path (step 1910). Otherwise, if the clinical practitioner or other care provider determines in step 1908 that limb perfusion is not adequate, the clinical practitioner or other care provider further inflates the balloon to widen the path through which blood can flow between the sheath body and the arterial wall (step 1906). The clinical practitioner or other care provider may also de-inflate the balloon when desired to avoid unnecessary radial stress on the artery. In one example, the clinical practitioner or other care provider inflates the balloon beyond a threshold above which the shape of the balloon changes to provide a blood flow path that is larger and better suited to the characteristics of a particular patient geometry or procedure.

[0077] FIG. 20 illustrates an exemplary cross-sectional view of a conventional system for sealing an access site with collagen. A patient's skin 2002 has a puncture site 2006 with an arteriotomy 2010 propagated through the space between the skin surface 2002 and an artery 2004. To prevent bleeding through the arteriotomy and between the arteriotomy and the skin, a conventional approach to sealing the access site is to inject collagen 2008 to fill the space between the skin puncture 2006 and the arteriotomy 2008, thereby sealing the arteriotomy. Patient geometries can vary widely, with the distance between the arteriotomy and the skin puncture ranging from about 2 cm in some patients to about 15 cm in some patients. Additionally, depending on the procedure and the clinical practitioner or other care provider, the insertion angle can vary, further contributing to the distance that must be covered by the sheath to reach the artery.

[0078] FIG. 21 illustrates an exemplary cross-sectional view of a sheath system for providing arteriotomy data according to one embodiment of the present disclosure. A patient's skin 2102 has a puncture site 2106 through which a sheath 2108 may be introduced. The sheath 2108 extends through the puncture site 2106 and through the arteriotomy into the artery 2104. The sheath 2108 includes a closure device 2110 at its distal end that extends over the arteriotomy, shown deployed in FIG. 21. At least one benefit of the sheath system of FIG. 21 is that the distance between the artery and the skin, and therefore the distance between the arteriotomy and the skin puncture, can be adjusted to provide useful data for a clinical worker or other care provider to use later during the procedure. At least another benefit of the sheath system of FIG. 21 is that the distance between the skin puncture and the arteriotomy can be adjusted to be independent of the patient's geometry.

[0079] FIG 22 illustrates an exemplary method for providing arteriotomy data using the sheath system of FIG 21. Process 2200 begins at step 2202 where a clinical practitioner or other care provider inserts a sheath through the patient's skin and into the artery. In step 2204, the clinical practitioner or other care provider checks whether the sheath has reached the artery. If not, the clinical practitioner or other care provider continues to insert the sheath and returns to step 2204. Otherwise, if the clinical practitioner or other care provider determines that the sheath is within the artery, i.e., an arteriotomy has been made in the artery and the distal end of the sheath is within the artery while the proximal end of the sheath is outside the patient's skin, process 200 proceeds to step 2206 where the clinical practitioner or other care provider places a closure device within the artery. In step 2208, the clinical practitioner or other care provider pulls back the sheath, causing the closure device to pull the artery closer towards the skin, reducing the distance between the artery and the skin; more specifically, reducing the distance between the arteriotomy and the skin puncture.

[0080] In step 2210, the clinical practitioner or other care provider checks whether the target distance between the arteriotomy and the skin puncture has been reached. For example, the clinical practitioner or other care provider may decrease the distance between the arteriotomy and the skin puncture until an increase in resistance is felt, indicating that the closure device is in contact with the access site, and then move the closure device away from the skin puncture by an amount equal to the target distance. For example, the target distance may be about 5 cm to about 10 cm. In another example, the target distance may be about 8 cm to about 9 cm. In another example, the target distance may be set by the clinical practitioner or other care provider, or may be set by default. If in step 2210 the clinical practitioner or other care provider determines that the target distance between the arteriotomy and the skin puncture has not been reached, the clinical practitioner or other care provider returns to step 2208 to continue retracting the sheath. Otherwise, if the clinical practitioner or other care provider determines that the target distance has been reached, process 2200 proceeds to step 2212 where the clinical practitioner or other care provider manipulates the closure device to allow for insertion of the medical device. In one example, between steps 2210 and 2212, the clinical practitioner or other care provider may attend to other aspects of the procedure. Alternatively, the clinical practitioner or other care provider may leave the procedure and a second clinical practitioner or other care provider may enter the procedure - the second clinical practitioner or other care provider may quickly continue the procedure using the target distance. In step 2214, the clinical practitioner or other care provider inserts the medical device through the sheath and into the artery. In one example, in the event that the procedure is indefinitely interrupted or terminated, step 2214 may be replaced by removal of the closure device and closure of the access site. As noted above with respect to FIG. 21 , at least one advantage of method 2200 is that the distance between the artery and the skin, and therefore the distance between the arteriotomy and the skin puncture, can be adjusted to provide useful data for a clinical practitioner or other care provider to use later during the procedure; as well as having a fixed distance between the skin puncture and the arteriotomy that is set independent of patient geometry.

[0081] 23 illustrates an exemplary method for controlling access site bleeding according to one embodiment of the present disclosure. Process 2300 begins at step 2302 where a clinical practitioner or other care provider inserts a sheath through the patient's skin. In step 2304, the clinical practitioner or other care provider inserts the sheath into the artery through an arteriotomy. In step 2306, the clinical practitioner or other care provider introduces a medical device through the sheath. After the medical device has been used, in step 2308, the clinical practitioner or other care provider retracts the sheath or medical device, or both. After retracting the sheath or medical device, the clinical practitioner or other care provider checks for access site bleeding in step 2310. If the clinical practitioner or other care provider determines in step 2310 that there is no excessive or undesirable access site bleeding, the process ends in step 2314.

[0082] Alternatively, if in step 2310 the clinical practitioner or other care provider observes excessive or undesirable access site bleeding, the process 2300 proceeds to step 2312 where the clinical practitioner or other care provider places a closure device in the artery. If the clinical practitioner or other care provider retracted only the sheath in step 2308, the closure device as deployed must be capable of accepting a catheter or any other element to pass therethrough. If the clinical practitioner or other care provider retracted both the sheath and medical device in step 2308, the closure device as deployed may not be capable of accepting a catheter or any other element to pass therethrough.

[0083] At least one advantage of method 2300 is that it can control bleeding at the access site either when the sheath is retracted but the medical device or at least a portion of the medical device is still within the patient, or when both the sheath and medical device are retracted, e.g., at the end of a procedure. Moreover, at least an additional advantage of method 2300 is that it can temporarily close bleeding at the access site while retaining the ability to pass the medical device and / or any other instruments through the closure device. In one example, the closure device is placed upstream from the arteriotomy. In another example, the closure device is placed at the arteriotomy. In one example, the closure device is placed for 30 seconds to 20 minutes. In another example, the closure device is placed for 30 seconds to 3 minutes.

[0084] FIG. 24 shows an exemplary diagram of a closure device placed upstream from an arteriotomy according to one embodiment of the present disclosure. In the example shown in FIG. 24, the closure device 2410 is a balloon that, when expanded, blocks or reduces the flow of blood from a location upstream from the arteriotomy to a location distal to the arteriotomy. At least one advantage of the closure device 2410 is that it can tamponade the access site (arteriotomy or skin puncture) to prevent excessive blood loss and to allow for closure or other clinical indications or procedures (such as attaching a graft to the access site). At least one benefit of the closure device 2410 is that it can be integrated with a sheath assembly and medical device. Thus, the closure device of FIG. 24 and the method of FIG. 25 described below provide a quicker and easier way to temporarily block blood flow, whereas existing techniques require a second insertion site where a guidewire and balloon catheter are inserted and placed, thus requiring additional steps and longer time to control blood flow. In one example, the closure device may be incorporated onto a sheath assembly, such as the sheath assembly described with respect to Figures 1-22. In another example, the closure device is incorporated onto the sheath assembly at any fixed location along the length of the sheath assembly. In another example, the closure device is placed onto an outer sheath or sleeve (e.g., outer sheath or sleeve 201 in Figure 5D) that can be moved longitudinally relative to the sheath assembly and catheter shaft until the closure device is positioned at a desired location upstream from the arteriotomy. In one example, the shape of the closure device is selected to match the anatomy of the location where the closure device will be placed. For example, a closure device used to block blood flow upstream from an axillary or subclavian arteriotomy is shaped differently than a closure device used to block blood flow upstream from the iliac or femoral arteries.

[0085] FIG. 25 illustrates an exemplary method for controlling bleeding at an access site using the closure device of FIG. 24. In an initial procedure, a clinical practitioner or care provider creates an arteriotomy and percutaneously inserts a sheath through the arteriotomy into the patient's artery (steps 2502, 2504). Additional steps may be performed by the clinical practitioner or care provider between the puncture and arteriotomy and the insertion of the sheath through the puncture and arteriotomy. For example, the clinical practitioner or other care provider may use a guidewire and may use a series of dilators to gradually enlarge both the puncture and the arteriotomy sufficiently to accept a sheath, which may be an introducer sheath or a repositioning sheath. The sheath is advanced until its distal end is positioned within the artery and the proximal end of the sheath is positioned outside the patient's body. The clinical practitioner or other care provider may then insert a medical device through the sheath and activate the medical device as part of the procedure. During the procedure, the clinical practitioner or other care provider notices unwanted or excessive bleeding at the access site that occludes the access site and creates a risk to the patient. The clinical practitioner or other care provider then inflates the balloon upstream from the arteriotomy (step 2506). After the initial inflation of the balloon upstream from the arteriotomy, the clinical practitioner or other care provider determines if the bleeding at the arteriotomy has been controlled (step 2508). For example, the clinical practitioner or other care provider may consider the bleeding to be controlled if the access site is visible or the bleeding has decreased. After a sufficient time, the clinical practitioner or other care provider may proceed to de-inflate the balloon (step 2510). For example, a sufficient time is the time required for the patient's blood to begin clotting at the access site. For example, the clinical practitioner or other care provider may choose to inflate the balloon for 30 minutes until the underlying problem causing the hematoma is identified, thereby blocking blood flow upstream from the arteriotomy and stopping the unexpected hematoma.Once identified and addressed, the clinician or other care provider may de-inflate the balloon while ensuring that the distal side of the patient's limb is still receiving adequate blood flow to prevent ischemia. In another example, a sufficient time is the time required for the clinician or other care provider to perform another procedure (e.g., a graft). Alternatively, if more time is required or if the clinician or other care provider determines that the arteriotomy bleeding is not adequately controlled, the clinician or other care provider may further inflate the balloon and later review whether the balloon has been inflated sufficiently to provide the desired blood flow control.

[0086] Compared to conventional techniques that require surgically opening an access site at skin level to expose the vessel sufficiently to allow clamping or ligation (particularly difficult in a catheter lab environment), method 2500 provides the user with the ability to endovascularly tamponade the vessel upstream of the access site. A clinician or other caregiver can inflate the balloon and adjust the balloon inflation to control blood flow without the user having to cut the skin beyond the puncture and without the user having to remove the blood pump. At least one benefit of method 2500 is the ability to tamponade upstream of an arteriotomy for a short period of time, such as to attach a pump to a graft without causing excessive blood loss to the patient. The closure device used as described in FIG. 25 may be any of the closure devices described with respect to FIGS. 23-28AB. Another exemplary benefit of method 2500 is that the temporary tamponade created by placing a closure device (e.g., a balloon) upstream from the arteriotomy allows for continued hemodynamic support to be provided to the patient while bleeding / oozing at the access site is stopped. The temporary tamponade may promote clotting at the access site, which solves the difficulties of bleeding and oozing, and allows a previously inserted medical device (e.g., a blood pump) to remain in place without the need for abrupt removal.

[0087] FIG. 26 illustrates an exemplary closure device for controlling bleeding at an access site according to one embodiment of the present disclosure. A clinician or other care provider inserts a sheath 2610 through a skin puncture 2602 and into an artery 2604, for example, as described with respect to any of FIGS. 11, 12, 14, 16, 19, 22, 23, and 25. The sheath 2610 includes a distal portion 2608, depicted in FIG. 26 as a foot plate. In the example of FIG. 26, the foot plate 2608 is disposed and extends longitudinally in the direction of the artery, surrounding and occluding the arteriotomy. In one example, the foot plate comprises one or more flaps that can pivot about an axis to move from a compressed state to an expanded or deployed state. In another example, the foot plate is a balloon. In one example, the foot plate may be a torus-shaped balloon. In another example, the foot plate may comprise more than one balloon. For example, the foot plate may be made of multiple inflatable balloons that extend radially outward. Alternatively, the foot plate may include both balloons and mechanical plates. The foot plate may be made of Nitinol or synthetic rubber or elastomer. As shown in FIG. 26, the device 2606 can still pass through the closure device 2608 if necessary. There is an opening in the center of the closure device. In one example, the opening is smaller than the access site. In another example, the opening is filled by a one-way device such as a flap or one-way valve. At least one benefit of the closure device of FIG. 26 is the ability to control blood through the arteriotomy without the user having to cut the skin beyond the puncture and still retain the ability to withdraw or insert elements within the patient's body.

[0088] 27A-B show an exemplary closure device for controlling bleeding at an access site before (FIG. 27A) and after (FIG. 27B) deployment according to one embodiment of the present disclosure. A clinical practitioner or other care provider inserts a sheath 2710 through an arteriotomy 2702, for example as described with respect to any of FIGS. 11, 12, 14, 16, 19, 22, 23, and 25. The sheath 2710 comprises a closure device at its distal portion; the closure device is compressed or retracted within the sheath 2710 in FIG. 27A for insertion into the patient (and is not shown). The clinical practitioner or other care provider may apply a relatively longitudinal motion to withdraw the closure device from the sheath or may trigger a release mechanism to deploy the closure device. In one example, the closure device comprises flaps that are longitudinally aligned along the length of the sheath but deploy upon release. In another example, the closure device comprises a balloon that is de-inflated during insertion of the sheath 2710 and inflated by the clinical practitioner or other care provider. In the example of FIG. 27B, the sheath 2710 is shown retracted, thereby deploying the closure device 2708 at the distal end of the sheath. The clinical practitioner or other care provider may further retract both the sheath and the closure device until the closure device contacts the arteriotomy 2702. At least one benefit of the closure device of FIG. 27 is the ability to control blood through the arteriotomy.

[0089] 28A-B show exemplary top and side views of an exemplary closure device for controlling bleeding at an access site according to one embodiment of the present disclosure. FIG. 28A shows a footplate type closure device having a foot 2802 and an opening or flap 2804 with a width w and a height h. The opening or flap 2804 allows for insertion of a medical device through the closure device even after the closure device is in place. FIG. 28B shows the same footplate type closure device with an opening or flap 2804 and a foot 2802. FIG. 28B shows that the closure device may be rotated so that it can be passed through an opening, such as arteriotomy 2810. In this manner, the closure device may be removed from the artery. The closure device of FIGS. 28A-B may be used as described, for example, with respect to FIGS. 23-27AB. At least one benefit of the closure device of FIGS. 28A-B is the ability to control blood through an arteriotomy.

Claims

1. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first end and the second end of the sheath body; inserting a sheath assembly through the skin puncture and into the artery at the arteriotomy; inserting a medical device through the first lumen; and opening a pathway through the sheath assembly to permit blood flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

2. The method of claim 1 , wherein the step of opening a passage through the sheath assembly comprises moving a cylindrical body relative to the sheath body.

3. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured to pass a medical device; and a second lumen configured to permit blood flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy.

1. A perfusion sheath assembly for insertion into a patient's blood vessel, comprising:

4. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first end and the second end of the sheath body, the first lumen configured for passage of a medical device; inserting a sheath assembly through the skin puncture and into the artery at the arteriotomy; and selectively opening and closing one or more openings in the sheath body along the longitudinal axis to permit blood flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy when the first end of the sheath body is positioned within a blood vessel and the second end of the sheath is outside the patient's body.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

5. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured for passage of a medical device; and a cylindrical body that selectively opens and closes openings in the sheath body along the longitudinal axis to permit blood flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy when the first end of the sheath body is positioned within a blood vessel and the second end of the sheath is outside the patient's body.

1. A perfusion sheath assembly for insertion into a patient's blood vessel, comprising:

6. a sheath body having a longitudinal axis and first and second ends; first and second lumens, each extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured for passage of a medical device and the second lumen configured to permit fluid flow from a blood vessel within the second lumen; and a stylet configured to selectively open and close the second lumen along the longitudinal axis to permit blood flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy when the first end of the sheath body is positioned within the blood vessel and the second end of the sheath is outside the patient's body.

1. A perfusion sheath assembly for insertion into a patient's blood vessel, comprising:

7. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured for passage of a medical device; a second lumen extending along the longitudinal axis between the first and second ends of the sheath body, the second lumen configured to permit flow of blood therethrough; inserting a sheath assembly through the skin puncture and into the artery at the arteriotomy; and selectively opening and closing an opening in the sheath body along the longitudinal axis by selectively moving a stylet through a second lumen to allow blood to flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy when the first end of the sheath body is positioned within a blood vessel and the second end of the sheath is outside the patient's body.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

8. a sheath body having a longitudinal axis, first and second ends, and at least one aperture between the first and second ends; a first lumen extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured for passage of a medical device; and a sleeve surrounding the sheath body and slidable along the sheath body to selectively open and close the at least one aperture between the first end and the second end of the sheath body when the first end of the sheath body is positioned within a blood vessel and the second end of the sheath is outside the patient's body.

1. A perfusion sheath assembly for insertion into a patient's blood vessel, comprising:

9. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured for passage of a medical device; A sleeve surrounding the sheath body inserting a sheath assembly through the skin puncture and into the artery at the arteriotomy; and selectively opening and closing an opening in the sheath body along the longitudinal axis by selectively moving the sleeve to allow blood to flow from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy when the first end of the sheath body is positioned within a blood vessel and the second end of the sheath is outside the patient's body.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

10. inserting a sheath having a first portion with a fixed diameter substantially similar to a diameter of the artery and an expandable distal portion through the skin puncture and into the artery at the arteriotomy; expanding the expandable distal portion of the sheath to expand the diameter of the artery to a diameter greater than the fixed diameter of the first portion; and inserting a medical device through the sheath and past the expandable distal portion into the artery. Including, the expandable distal portion of the sheath is configured to permit blood flow through the artery from upstream of the arteriotomy to downstream of the arteriotomy. A method for percutaneously inserting a medical device into a patient's blood vessel.

11. 11. The method of claim 10, further comprising the step of introducing an anticoagulant into the artery.

12. A sheath having a proximal portion with a fixed diameter substantially similar to the diameter of a blood vessel and an expandable distal portion. Equipped with when the distal portion of the sheath body is expanded and positioned within the blood vessel and at least a portion of the proximal portion of the sheath is outside the patient's body, the expandable distal portion of the sheath is configured to permit blood flow through the expanded distal portion from upstream of the arteriotomy to downstream of the arteriotomy. A perfusion sheath assembly for insertion into a patient's vasculature.

13. The perfusion sheath assembly of claim 12 , wherein the distal portion is porous.

14. The perfusion sheath assembly of any one of claims 12 to 13, wherein the distal portion is mesh.

15. The perfusion sheath assembly of any one of claims 12 to 14, wherein the distal portion is a stent.

16. 16. The perfusion sheath assembly of any one of claims 12 to 15, wherein a shape of the expandable distal portion of the sheath when expanded is an S-shape having a first curvature and a second curvature, at least one of the first curvature and the second curvature configured to allow blood to flow through the expanded distal portion from upstream of the arteriotomy to downstream of the arteriotomy.

17. inserting a sheath assembly having a lumen through which blood can flow through the first skin puncture and into the artery at the first arteriotomy; inserting a second sheath through a second skin puncture and into the artery at a second arteriotomy distal to the first arteriotomy; and opening fluid communication between the lumen and the second sheath so that blood can flow from the lumen through the second sheath and into the artery.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

18. a first sheath configured for insertion through the first skin puncture and into the artery at the first arteriotomy; a lumen extending along the first sheath configured to permit blood flow; and a second sheath configured for insertion through a second skin puncture and into the artery at a second arteriotomy distal to the first arteriotomy. Equipped with the lumen and the second sheath are configured to be in fluid communication such that blood can flow from the lumen, through the second sheath, and into the artery downstream from the first arteriotomy. A perfusion sheath assembly for insertion into a patient's vasculature.

19. The perfusion sheath assembly of claim 18 , wherein the lumen is integrally formed with the first sheath.

20. The perfusion sheath assembly of any one of claims 18 to 19, wherein the lumen is concentric with the first sheath.

21. The perfusion sheath assembly of any one of claims 18 to 20, wherein the lumen is within a first sheath.

22. The perfusion sheath assembly of any one of claims 18 to 21, wherein the lumen is eccentric from the first sheath.

23. The perfusion sheath assembly of any one of claims 18 to 22, wherein the lumen is external to the first sheath.

24. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first end and the second end of the sheath body; and A balloon connected to the sheath body. inserting a sheath assembly through the skin puncture and into the artery at the arteriotomy; and inflating the balloon to open a passage between the sheath body and a wall of the artery, wherein blood flows through the passage from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

25. a sheath body having a longitudinal axis and first and second ends; a first lumen extending along the longitudinal axis between the first end and the second end of the sheath body; and a balloon coupled to the sheath body, the balloon configured, upon inflation, to open a fluid pathway between the sheath body and a wall of the artery such that blood can flow through the fluid pathway from a portion of the artery on a first side of the arteriotomy to a portion of the artery on a second side of the arteriotomy; A sheath assembly configured for insertion through a skin puncture into an artery at an arteriotomy, comprising:

1. A perfusion sheath assembly for insertion into a patient's blood vessel, comprising:

26. 26. The perfusion sheath assembly of claim 25, wherein the first lumen is integrally formed with the sheath body.

27. The perfusion sheath assembly of any one of claims 25 to 27, wherein the first lumen is within the sheath body.

28. The perfusion sheath assembly of any one of claims 25 to 28, wherein the first lumen is eccentric from the sheath body.

29. The perfusion sheath assembly of any one of claims 25 to 28, wherein the balloon extends along at least a portion of the sheath body when inflated.

30. The perfusion sheath assembly of any one of claims 25 to 29, wherein the shape of the balloon is configured to open a fluid pathway.

31. The perfusion sheath assembly of any one of claims 25 to 30, wherein the balloon surrounds the sheath body less than 360 degrees; and the fluid pathway between the sheath body and the wall of the artery is around the sheath body where the balloon does not surround the sheath body.

32. The perfusion sheath assembly of any one of claims 25 to 31, wherein the balloon completely surrounds the sheath body and has a cross-section with an internal channel; and a fluid pathway between the sheath body and the wall of the artery passes through the internal channel.

33. The perfusion assembly of any one of claims 25 to 32, wherein the balloon cross section is a torus.

34. inserting the sheath assembly through the skin puncture and into the artery at the arteriotomy; passing a medical device through the sheath assembly; and manipulating the sheath assembly to simultaneously ensure hemostasis through the arteriotomy while permitting blood flow between a location distal to the arteriotomy and a location upstream from the arteriotomy.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

35. 35. The method of claim 34, wherein the step of manipulating the sheath assembly includes moving a first component of the sheath assembly relative to a second component of the sheath assembly to create a flow path.

36. 36. The method of any one of claims 34-35, wherein ensuring hemostasis through the arteriotomy comprises placing a closure device at or distal to the arteriotomy.

37. A sheath assembly comprising at least one sheath, at least one lumen, and at least one closure device. Equipped with the sheath assembly is configured for insertion through a skin puncture and into an artery at an arteriotomy; and the sheath assembly is configured to permit blood flow between a location distal to the arteriotomy and a location upstream from the arteriotomy while simultaneously ensuring hemostasis through the arteriotomy. A perfusion sheath assembly for insertion into a patient's vasculature.

38. 40. The perfusion sheath assembly of claim 37, wherein the sheath assembly comprises a sheath with an aperture.

39. The perfusion sheath assembly of any one of claims 37 to 38, wherein the sheath assembly further comprises a stylet configured to slide within the sheath to open and close the aperture.

40. The perfusion sheath assembly of any one of claims 37 to 39, wherein the sheath assembly further comprises a sleeve configured to slide around the sheath to open and close the aperture.

41. The perfusion sheath assembly of any one of claims 37 to 40, wherein the sheath assembly further comprises a closure device.

42. The perfusion sheath assembly of any one of claims 37 to 41, wherein the closure device is a balloon.

43. The perfusion sheath assembly of any one of claims 37 to 42, wherein the closure device is a foot plate.

44. inserting a sheath assembly through the skin puncture and into the artery at the arteriotomy, the diameter of the sheath assembly being substantially equal to the diameter of the artery; passing a medical device through the sheath assembly; and allowing blood to flow between a location distal to the arteriotomy and a location upstream from the arteriotomy while simultaneously ensuring hemostasis through the arteriotomy.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

45. inserting a sheath assembly including a closure device through the skin puncture and into the artery at the arteriotomy; placing the closure device inside the artery, the closure device providing hemostasis at the arteriotomy; moving the closure device toward the skin puncture such that the distance between the arteriotomy and the skin puncture is reduced to a target distance; and manipulating the closure device to allow for insertion of a medical device into the artery.

1. A method for percutaneously inserting a medical device into a blood vessel of a patient, comprising:

46. 46. ​​The method of claim 45, wherein the step of manipulating the closure device comprises rotating the closure device such that a cross-section of the closure device is smaller than a cross-section of the arteriotomy.

47. The method of any one of claims 45-46, wherein the step of manipulating the closure device further comprises temporarily retracting the closure device.

48. The method of any one of claims 45 to 47, wherein the step of manipulating the closure device comprises folding the closure device to a smaller cross section.

49. The method of any one of claims 45 to 48, wherein the step of manipulating the closure device comprises de-inflating the closure device.

50. 50. The method of any one of claims 45 to 49, further comprising using the target distance to guide insertion of the medical device.

51. The method of any one of claims 45 to 50, wherein the target distance is the same across a range of patients.

52. inserting a sheath assembly including a sheath and a closure device at a distal end of the sheath through the skin puncture and into the artery at the arteriotomy; and deploying the closure device positioned within the artery from a compressed state to an expanded state.

1. A method for preventing bleeding at an access site for a medical device inserted into a patient's blood vessel, comprising:

53. 53. The method of claim 52, wherein the closure device is a balloon.

54. 54. The method of any one of claims 52-53, further comprising inflating a balloon distal to the arteriotomy.

55. 55. The method of any one of claims 52-54, further comprising inflating a balloon at the arteriotomy to stop blood flow through the arteriotomy.

56. The method of any one of claims 52-55, wherein the closure device is a footplate.

57. The method of any one of claims 52-56, wherein the step of deploying the closure device further comprises displacing the sheath relative to the closure device to deploy the foot plate.

58. inserting a sheath assembly including a sheath and a closure device coupled to a distal end of the sheath through the skin puncture and into the artery at the arteriotomy; passing a medical device through the sheath and into the artery; withdrawing the sheath from the artery; and deploying the closure device at the arteriotomy from a compressed state to an expanded state to prevent blood flow through the arteriotomy.

1. A method for preventing bleeding at an access site for a medical device inserted into a patient's blood vessel, comprising:

59. 60. The method of claim 58, wherein the closure device is a balloon and the step of deploying the closure device comprises inflating the balloon.

60. The method of any one of claims 58-59, wherein the balloon, upon inflation, wraps around a portion of the medical device within the artery.

61. 61. The method of any one of claims 58-60, further comprising adjusting the inflation level of the balloon such that the balloon substantially seals off the artery to prevent blood flow through the arteriotomy.

62. 62. The method of any one of claims 58-61, wherein the closure device is a foot plate and the step of deploying the closure device comprises opening the foot plate.

63. 63. The method of any one of claims 58-62, wherein the footplate, when opened, rests against the inner surface of the artery and occludes the arteriotomy.

64. The method of any one of claims 58-63, wherein a diameter of the footplate upon expansion substantially matches a diameter of the artery.

65. inserting a sheath assembly including a sheath and a closure device coupled to a distal end of the sheath through the skin puncture and into the artery at the arteriotomy; passing a medical device through the sheath and into the artery; withdrawing the sheath and the medical device from the artery; and deploying the closure device at the arteriotomy from a compressed state to an expanded state to prevent blood flow through the arteriotomy.

1. A method for preventing bleeding at an access site for a medical device inserted into a patient's blood vessel, comprising:

66. 66. The method of claim 65, wherein the closure device is a balloon and the step of deploying the closure device comprises inflating the balloon.

67. 67. The method of any one of claims 65-66, further comprising adjusting the inflation level of the balloon such that the balloon substantially seals off the artery to prevent blood flow through the arteriotomy.

68. The method of any one of claims 65-67, wherein the diameter of the balloon when inflated is substantially similar to the diameter of the artery.

69. The method of any one of claims 65-68, wherein the closure device is a foot plate and the step of deploying the closure device comprises opening the foot plate.

70. The method of any one of claims 65-69, wherein the footplate, when opened, rests against the inner surface of the artery and occludes the arteriotomy.

71. inserting a sheath assembly including a sheath and a closure device coupled to a distal end of the sheath through the skin puncture and into the artery at the arteriotomy; passing a medical device through the sheath and into the artery; and deploying the closure device from a compressed state to an expanded state at a location distal to the arteriotomy to prevent blood flow through the arteriotomy.

1. A method for preventing bleeding at an access site for a medical device inserted into a patient's blood vessel, comprising:

72. 72. The method of claim 71, wherein the closure device is a foot plate and the step of deploying the closure device comprises opening the foot plate.

73. 73. The method of any one of claims 71-72, wherein the diameter of the footplate when opened is similar to the inner diameter of the artery, such that the footplate occludes the artery.

74. The method of any one of claims 71-73, wherein the closure device is a balloon and the step of deploying the closure device comprises inflating the balloon.

75. 75. The method of any one of claims 71-74, wherein the diameter of the balloon when inflated is similar to the inner diameter of the artery, such that the balloon occludes the artery.

76. a sheath body having a longitudinal axis and first and second ends; first and second lumens, each extending along the longitudinal axis between the first and second ends of the sheath body, the first lumen configured for passage of a medical device and the second lumen configured to permit fluid flow from a blood vessel within the second lumen; and a stylet configured to selectively open and close the second lumen along the longitudinal axis when the first end of the sheath body is positioned within the blood vessel and the second end of the sheath is outside the patient's body.

1. A perfusion sheath assembly for insertion into a patient's blood vessel, comprising:

77. 77. The perfusion sheath assembly of claim 76, wherein the stylet is configured to move along the second lumen to open and close the second lumen.

78. 78. The perfusion sheath assembly of any one of claims 76-77, wherein the sheath body comprises at least one aperture allowing fluid communication between the second lumen and the blood vessel.

79. The perfusion sheath assembly of any one of claims 76-78, wherein each aperture has a cross-sectional area similar to a cross-sectional area of ​​the second lumen.

80. The perfusion sheath assembly of any one of claims 76 to 79, wherein the at least one aperture comprises a single continuous channel.

81. 81. The perfusion sheath assembly of any one of claims 76-80, wherein each aperture is configured to prevent passage of a stylet therethrough and into a blood vessel as the stylet moves along the second lumen.

82. The perfusion sheath assembly of any one of claims 76-81, wherein the stylet comprises an internal lumen extending along a longitudinal axis between first and second ends of the stylet.

83. The perfusion sheath assembly of any one of claims 76 to 82, wherein a first end of the stylet comprises a skive.

84. The perfusion sheath assembly of any one of claims 76-83, wherein the lumen is exposed at the second end of the stylet.

85. The perfusion sheath assembly of any one of claims 76-84, further comprising an internal stylet for plugging an inner lumen of the stylet when the stylet is not in use.

86. The perfusion sheath assembly of any one of claims 76-85, further comprising a valve at a second end of the stylet for sealing the lumen when the stylet is not in use.

87. The perfusion sheath assembly of any one of claims 76 to 86, further comprising a guidewire configured to move along the lumen of the stylet.

88. The perfusion sheath assembly of any one of claims 76-87, wherein the stylet comprises markings to indicate a position of the stylet relative to the second end of the sheath body.

89. The perfusion sheath assembly of any one of claims 76-88, further comprising a ratchet mechanism for retracting the stylet toward the second end of the sheath body in standard increments.

90. The perfusion sheath assembly of any one of claims 76-89, wherein the increment is sized relative to the spacing between adjacent apertures.

91. 91. The perfusion sheath assembly of any one of claims 76-90, further comprising a hub coupled to the second end of the sheath body, the hub being in fluid communication with the first lumen.

92. The perfusion sheath assembly of any one of claims 76 to 91, wherein the hub also communicates with the second lumen, the hub configured to receive a stylet.

93. The perfusion sheath assembly of any one of claims 76-92, wherein the sheath body comprises an atraumatic tip attached to a first end of the sheath body.

94. 94. The perfusion sheath assembly of any one of claims 76 to 93, wherein the tip comprises an inner surface defining a tip lumen extending between a proximal end and a distal end of the tip, the tip lumen being in fluid communication with the first and second lumens of the sheath body.

95. The perfusion sheath assembly of any one of claims 76-94, wherein an outer diameter of a proximal end of the tip is greater than an outer diameter of a distal end of the tip such that the tip is tapered.

96. The perfusion sheath assembly of any one of claims 76-95, wherein a diameter of an inner surface at a proximal end of the tip is equal to a diameter of an inner surface at a distal end of the tip.

97. 97. The perfusion sheath assembly of any one of claims 76 to 96, wherein the distal portion comprises at least one of ethylene vinyl acetate (EVA), styrene-butadiene copolymer (SBC), synthetic rubber, an elastomer, a resilient material, a material with a modulus of elasticity of about 1.6 ksi, and a material with a yield strain of greater than 200%.

98. The perfusion sheath assembly of any one of claims 76-97, wherein the sheath body comprises a first material.

99. The perfusion sheath assembly of any one of claims 76-98, wherein the stylet comprises a second material.

100. The perfusion sheath assembly of any one of claims 76-99, wherein the second material is substantially stiffer than the first material and the first material is substantially more elastic than the second material.

101. 101. The perfusion sheath assembly of any one of claims 76-100, wherein the first material comprises at least one of ethylene vinyl acetate (EVA), styrene-butadiene copolymer (SBC), synthetic rubber, an elastomer, a resilient material, a material having a modulus of elasticity of about 1.6 ksi, and a material having a yield strain of greater than 200%.

102. The perfusion sheath assembly of any one of claims 76 to 101, wherein the second material comprises polyetheretherketone (PEEK), polyether block amide (such as PEBAX), a polyethylene material, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, a low density polyethylene (LDPE) material, a crack resistant material, a material with a low coefficient of friction, and a material with a modulus of elasticity of about 40 ksi.

103. 4. The perfusion sheath assembly of claim 3, inserted into a patient's blood vessel by the method of any one of claims 1 and 2.

104. 7. The perfusion sheath assembly of any one of claims 5 and 6, inserted into a patient's blood vessel by the method of any one of claims 1, 2 and 4.

105. 9. The perfusion sheath assembly of claim 8, inserted into a patient's blood vessel by the method of any one of claims 1, 2, 4, and 7.

106. 17. The perfusion sheath assembly of any one of claims 12 to 16, inserted into a patient's blood vessel by a method according to any one of claims 9 to 11.

107. 24. The perfusion sheath assembly of any one of claims 18 to 23, inserted into a patient's blood vessel by the method of claim 17.

108. 34. The perfusion sheath assembly of any one of claims 25 to 33, inserted into a patient's blood vessel by the method of claim 24.

109. 44. The perfusion sheath assembly of any one of claims 37 to 43, inserted into a patient's blood vessel by the method of any one of claims 34 to 36.

110. The perfusion sheath assembly of any one of claims 76-102, inserted into a patient's blood vessel by the method of any one of claims 37-75.

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