Expandable sheath and liner therefor

Abstract

An expandable sheath body for a sheath assembly. The sheath body has a tubular frame with a lumen therein. The frame has a gap therein. The frame is expandable to a larger diameter and contractible to a smaller diameter and is flexible. The sheath body has an inner liner formed on a surface of the lumen defined by the tubular frame and an outer liner formed on an outer surface of the frame. The inner liner and the inner layer of the multi-layer outer liner can be made of expanded polytetrafluoroethylene. The expanded polytetrafluoroethylene can be infused with silicone oil to enhance lubricity.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 341,252, filed May 12, 2022, the disclosure of which is incorporated herein by reference. [Background technology]

[0002] background

[0002] An intracardiac heart pump assembly may be introduced surgically or percutaneously into the heart and used to deliver blood from one location in the heart or circulatory system to another location in the heart or circulatory system. For example, when deployed in the heart, the intracardiac pump may pump blood from the left ventricle of the heart to the aorta or from the inferior vena cava to the pulmonary artery. An intracardiac pump may be powered by a motor (and associated drive cable) located outside the patient's body or an internal motor located inside the patient's body. Some intracardiac blood pump systems can operate in parallel with the native heart to supplement cardiac output and partially or completely unload the heart's components. Examples of such systems include the IMPELLA® family of devices (Abiomed, Inc., Danvers Mass.).

[0003] In one common approach, an intracardiac blood pump is catheterized through the femoral artery using an introducer sheath (which may be a peelable introducer sheath). The sheath may alternatively be inserted elsewhere, such as into the femoral vein or into the delivery pathway for the pump to support either the left or right side of the heart.

[0004]

[0004] An introducer sheath can be inserted into the femoral artery through an arteriotomy to form an insertion path for the pump assembly. A portion of the pump assembly is then advanced into the artery through the lumen of the introducer sheath. The required size of the arteriotomy is of great concern. Therefore, expandable introducer sheaths have been developed so that a smaller arteriotomy opening is required to accommodate the sheath and the medical instrument passing therethrough. Therefore, there is a continuing need for improved expandable introducer sheaths. Summary of the Invention [Means for solving the problem]

[0005] overview

[0005] According to some aspects, the expandable introducer sheath includes a liner positioned within the sheath, which may be constructed and arranged to reduce friction as the medical device is threaded through the sheath. The reduced friction facilitates passage of the medical device through the sheath, which ease of passage is exploited to provide an at least nominally smaller diameter sheath that requires at least a nominally smaller arteriotomy opening through which the sheath is introduced into the patient. "Diameter" as used herein is used to represent the distance from one side of the introducer sheath or medical device to the other. Diameter does not imply that the introducer sheath or introducer sheath lumen or device cross section is precisely circular. In some embodiments, the liner is formed from polytetrafluoroethylene (ePTFE).

[0006]

[0006] Described herein is an introducer sheath assembly having a tubular frame having an internal lumen therein, the tubular frame configured to temporarily expand from a first diameter to a second, larger diameter when a portion of a medical device having a diameter greater than the first diameter passes through the tubular frame. The introducer sheath assembly also has a liner adjacent an inner surface of the tubular frame, the liner being formed from expanded polytetrafluoroethylene (ePTFE), and a hub coupled to a proximal end of the tubular frame, the hub containing a hemostatic valve.

[0007] In one aspect, the ePTFE liner is attached to the inner surface of the tubular frame. In another aspect, a primer is formed between the ePTFE liner and the inner surface of the lumen defined by the tubular frame. In another aspect, the introducer sheath assembly has an outer liner formed on the outer surface of the tubular frame. The tubular frame can be made of braided nitinol tubing or laser cut hypotube.

[0008]

[0008] In one embodiment, the outer liner is made of thermoplastic polyurethane or expanded polytetrafluoroethylene. The outer liner may be single or multi-layered. In one embodiment, the outer liner has two layers. A first layer may be formed on the outer surface of the frame, and the first layer may be made of thermoplastic polyurethane. A second layer of the two layers of the outer liner is formed on the first layer, and the second layer may be made of polytetrafluoroethylene.

[0009]

[0009] Also disclosed herein is an expandable sheath body. The expandable sheath body has a tubular frame with a lumen therein, the frame having a gap, the frame is expandable to a larger diameter, contractable to a smaller diameter, and flexible. The expandable sheath body has an inner liner formed on a surface of the lumen defined by the tubular frame and an outer liner formed on an outer surface of the frame. In one aspect, a primer is formed between the inner liner and the surface of the lumen defined by the tubular frame. In a further aspect, a primer is formed between the outer liner and the outer surface of the frame.

[0010]

[0010] In a further aspect, the frame can be made from either braided nitinol tubing or laser cut hypotubes. In a further aspect, the inner liner can be made from expanded polytetrafluoroethylene. In a further aspect, the expandable sheath can have an outer liner, which can be made from thermoplastic polyurethane or expanded polytetrafluoroethylene, and can be multi-layered. If the outer liner of the expandable sheath is multi-layered, in one aspect, the multi-layered outer liner can have two layers, where a first layer is formed on the outer surface of the frame, and the first layer comprises thermoplastic polyurethane. The second layer of the two layers of the outer liner is formed on the first layer, and the second layer comprises expanded polytetrafluoroethylene. [Brief description of the drawings]

[0011] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1]

[0011] A sheath assembly is shown. [Diagram 2]

[0012] 2 illustrates a first sheath body configured for use in a sheath assembly such as that shown in FIG. 1 . [Diagram 3]

[0013] FIG. 3 is a cross-sectional view of the sheath body of FIG. 2 taken across axis AA. [Figure 4]

[0014] 4 is a schematic diagram of a side wall portion A of the sheath body of FIG. 3. FIG. [Diagram 5]

[0015] 2 illustrates a second sheath body configured for use in a sheath assembly such as that shown in FIG. 1. [Figure 6]

[0016] FIG. 6 is a cross-sectional view of the sheath body of FIG. 5 taken across the BB axis. [Figure 7]

[0017] 7 is a schematic diagram of a side wall portion B of the sheath body of FIG. 6. FIG. [Figure 8]

[0018] 2 illustrates a third sheath body configured for use in a sheath assembly such as that shown in FIG. 1. [Figure 9]

[0019] FIG. 9 is a cross-sectional view of the sheath body of FIG. 8 taken across the CC axis. [Figure 10]

[0020] 10 is a schematic diagram of a side wall portion C of the sheath body of FIG. 9. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Detailed Description

[0021] Aspects of the present disclosure will be described in detail with reference to the figures in which like reference numerals identify similar or identical elements. It should be understood that the disclosed aspects are merely examples of the present disclosure, which may be embodied in various forms. Well-known functions or structures are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein should not be construed as limiting, but merely as a basis for claims and as a representative basis for teaching those skilled in the art to employ the present disclosure in various ways in substantially any appropriately detailed structure.

[0013]

[0022] In order to provide a general understanding of the systems, methods, and devices described herein, certain exemplary embodiments are described. Although the apparatus and features thereof described herein are specifically described for use in connection with an intracardiac pump system, it will be understood that all components and other features outlined below can be combined with each other in any suitable manner and can be adapted and applied to other types of medical devices, such as electrophysiology study and catheter ablation devices, angioplasty and stenting devices, angiography catheters, peripherally inserted central catheters, central venous catheters, midline catheters, peripheral catheters, inferior vena cava filters, abdominal aortic aneurysm treatment devices, thrombus removal devices, TAVR delivery systems, cardiac therapy and cardiac assist devices including balloon pumps, cardiac assist devices implanted using a surgical incision, and other venous or arterial based introducer catheters and devices.

[0014]

[0023] Because commercially available introducer sheaths are generally not radially expandable, the inner diameter of the introducer sheath must always be large enough to accommodate the largest diameter portion of the pump assembly, such as the pump head, even if other portions of the pump assembly, such as the catheter, have a significantly smaller diameter. In this example, the introducer requires a relatively large vascular opening (e.g., arteriotomy) to pass the pump catheter through the introducer sheath and into the blood vessel, which can complicate arteriotomy closure at the end of the procedure.

[0015]

[0024] Some medical introducers used for applications other than heart pump insertion have an expandable sheath body that can be expanded to pass a larger diameter percutaneous device through a smaller diameter sheath lumen into a patient's vasculature. Generally, these introducer sheaths, when inserted, have an inner diameter that is smaller than the outer diameter of the device being introduced. The introducer sheath may expand to allow the device to pass through the introducer sheath and into the vasculature, and then relax to a smaller diameter state after the larger diameter portion of the device has passed. In the current state of the industry, these expandable introducers require distinct expandable features, such as longitudinal folds or wrinkles, or a lumen for injecting fluids (e.g., saline), to transition from a compressed state to an expanded state. As a result, such commercially available expandable sheaths are typically fully flexible and therefore do not provide any stiffness within their structure, thereby resulting in kinking or buckling during insertion or withdrawal of a percutaneous medical device. Although expandable sheaths have many advantages, improvements in design and performance are continually sought.

[0016]

[0025] The systems, methods, and devices described herein provide an expandable sheath body configured for use in an expandable sheath assembly for inserting a medical device (e.g., an intracardiac heart pump) into a blood vessel through a vascular aperture. The inventors have recognized and appreciated that an expandable sheath system may provide numerous advantages over conventional non-expandable sheaths. For example, by allowing temporary expansion during insertion of a medical device, an expandable sheath may allow for a smaller vascular aperture size (i.e., arteriotomy size) for delivering the medical device compared to a non-expandable sheath that must have an inner diameter at least as large as the maximum diameter of the medical device to be passed therethrough. However, the inventors have further recognized that as the luminal cross-section of the expandable sheath is reduced (e.g., to a nominal or resting cross-section smaller than the maximum diameter portion of the medical device to be passed therethrough), passage of the medical device through the introducer sheath may become more difficult during insertion and / or removal of the medical device. Thus, the systems, methods, and devices described herein provide an expandable sheath system with reduced insertion and / or removal forces, thereby enabling further reduction in sheath diameter and corresponding reduction in vascular aperture size.

[0017]

[0026] The expandable sheath body described herein can be used in an expandable sheath assembly including a dilator assembly. As described, the expandable sheath body has an inner surface and an outer surface, the inner surface defining a lumen extending between a proximal end and a distal end of the sheath body. Optionally, the expandable sheath assembly can include a hemostatic stylet in addition to the expandable sheath body. The expandable sheath assembly (including the expandable sheath body, the dilator assembly, and the optional hemostatic stylet) is particularly advantageous over existing expandable sheath assemblies for patients with coronary artery disease (CAD) and peripheral arterial disease who exhibit arterial calcification and tortuosity that make delivery of introducer sheaths and catheters difficult.

[0018]

[0027] The expandable sheath assembly having the sheath body described herein is easier to insert than conventional assemblies due to its reduced insertion profile, increased flexibility, reduced friction, and reduced risk of kinking under load. The reduced insertion profile reduces complications associated with insertion, reduces stretching and loading of the vessel opening, and reduces the risk of limb ischemia. The construction of the sheath body described herein allows the sheath body to be advanced within a lumen (e.g., a blood vessel) and provides sufficient axial stiffness such that the sheath body resists buckling, while maintaining bending flexibility and kink resistance and reducing frictional forces to prevent "finger trapping." Additionally, the sheath body constructions described herein provide an improvement over existing introducer sheath bodies by having at least one or both of an inner or outer liner, each liner constructed and arranged to reduce the force required to expand the sheath body (compared to the force required to expand a sheath having a coating without bias) and, at least in the example of a sheath body having an inner liner described herein, minimize device insertion and removal forces by reducing friction between the sheath body and a device inserted therethrough.

[0019]

[0028] The sheath body can expand between different states to accommodate the medical device as it is threaded through the sheath. For example, the sheath body is elongated (typically with a dilator) in a first, smaller diameter state for insertion and relaxed to a second, larger diameter state once at the desired location to allow a portion of the medical device to pass through the lumen, the portion of the medical device having a cross-sectional area larger than that of the lumen in the first state. In the different configurations, the diameter of the sheath body is expanded between a rest state when the sheath is deployed at the desired location and a larger diameter state when the medical device is threaded through the sheath body. After the medical device has passed through the sheath, the sheath can retract or otherwise relax and return to the rest state of the smaller diameter. In either configuration, the expandable sheath assembly with the sheath body described herein does not require additional elements relative to a standard introducer assembly. That is, the assemblies described herein are free of at least: i) an external balloon; ii) folds in the expandable sheath body; and iii) a second sheath for delivery. This simplifies (eg, requires fewer steps and is less time consuming) the use of an expandable sheath assembly having a sheath body as described herein.

[0020]

[0029] Additionally, the instantaneous expansion of the sheath body from the elongated state to the relaxed state (or from the relaxed state to the expanded state) reduces the size of the opening, e.g., arteriotomy, required to insert the sheath into the patient's vasculature. Minimizing the time the sheath body is in the expanded state also reduces damage to the vessel wall that may occur if the sheath body is maintained in the expanded state for an extended period of time. Additionally, the smaller the opening required to receive the sheath body in the relaxed or collapsed state reduces the risk of thrombotic occlusion of the vessel receiving the sheath body.

[0021]

[0030] As described above, the expandable sheath can deliver the sheath body into the patient's vasculature with a small profile if it is held in an axial tension (pulled down) prior to insertion. This has the following important advantages: i) it is pulled down to a small insertion profile to minimize complications associated with insertion (i.e. bleeding, vessel injury, high insertion force); and ii) it maintains a "soft" sheath body and instantaneous expansion for interaction at the arteriotomy site to allow for small inner diameter closure and minimal bleeding due to minimized vessel shrinkage during use. However, it should be understood that some sheath configurations according to the present disclosure may not be pulled down prior to insertion into the vessel. For example, the sheath may be inserted and maintained in a relaxed state within the vessel, and then may momentarily expand to a larger diameter as the medical device passes through the sheath, as described above.

[0022]

[0031] FIG. 1 illustrates a sheath assembly 100 according to an embodiment of the presently disclosed technology. The sheath assembly 100 has a hub 110 that locks the sheath in place once inserted. The hub 110 cooperates with a cap 120 to secure a sheath body 130 in place. The hub 110 also has detents 112 (only one of which is visible) to aid in attaching the hub 110 to a dilator hub 230. A butterfly / suture pad 140 is configured to aid in attaching the sheath assembly 100 to a patient (e.g., by suturing the assembly to the patient). In this description, the proximal end of the assembly is at the hub / cap end and the distal end of the assembly is at the tip end. Fluids can be introduced into the assembly via a side arm channel 160, and the flow of fluid into the device can be controlled by a stopcock 170. A hemostasis valve (not shown) may also be included in the hub 110, configured to prevent blood from leaking outside of the patient during insertion and / or removal of an intracardiac blood pump or other components. Any suitable hemostasis valve may be employed with the sheath assemblies described herein, examples of which are described and shown in U.S. Patent Application No. 17 / 097,582, filed November 13, 2020, and published May 20, 2021 as U.S. Patent Application Publication No. 20210146111, which is incorporated herein by reference. Additionally, in some embodiments, the hub 110 may include a foam insert (not shown) disposed proximal to the hemostasis valve, which may be impregnated with a lubricant, such as silicone, to lubricate components as they are inserted through the foam into the sheath body 130.

[0023]

[0032] 2-10 show various sheath body structures configured for use with the sheath assembly 100 according to embodiments of the presently disclosed technology. In all embodiments, the expandable sheath body 200, 300, 400 includes a multi-layer structure having a circumferential frame 202, 302, 402 interposed between an inner liner 204, 304, 404 and an outer liner 206, 306, 406. The frame 202, 302, 402 can be formed of any suitable material. To provide an expandable frame that is suitably kink resistant, the expandable frame 202, 302, 402 can be a braided material. Alternatively, the frame can be a hypotube in which gaps are introduced by laser cutting. Hypotubes are typically made of metal. In further embodiments, the braided material is a metallic material that has both elasticity and shape memory properties. One example of a suitable braided material is a braid formed from Nitinol. In some embodiments according to the present disclosure, the frame 202, 302, 402 is an expandable braided frame made up of strands of a flexible metal, such as Nitinol. The frame 202, 302, 402 can have an expansion mechanism that aids in the expansion and / or contraction of the frame. For example, the strands of the braided frame can be configured to have a bias to expand and / or contract from a resting position. According to some embodiments, the expansion mechanism allows the strands of the braided frame to slide relative to each other as the frame expands and contracts.

[0024]

[0033] Each of the inner liner 204, 304, 404 and outer liner 206, 306, 406 is a low friction layer applied to the frame 202, 302, 402 to mitigate (i.e., reduce) the force required to insert and remove a device (e.g., an intracardiac heart pump) by reducing the frictional forces that occur during insertion and removal. Additionally, the inner liner 204, 304, 404 and outer liner 206, 306, 406 may allow the sheath to expand with a relatively small required force compared to the force required to expand the sheath without the liner. As shown in Figures 2-10, the inner liner 204, 304, 404 and the outer liner 206, 306, 406 are applied (or bonded) to the inner surface 208, 308, 408 of the frame 202, 302, 402 and the outer surface 210, 310, 410 of the frame 202, 302, 402, respectively, using a thermoforming process (also known as lamination). Because the frame is braided in these embodiments, the inner and outer layers may bond to each other through the gaps in the braid. Thus, the inner and outer liner materials are selected to expand and contract in cooperation with the sheath frame.

[0025]

[0034] As shown in Figures 3-4, 6-7, and 9-10, the sheath body 200, 300, 400 may further include an inner primer layer 212, 312, 412 interposed between the inner surface 208, 308, 408 of the frame 202, 302, 402 and the inner liner 204, 304, 404, and an outer primer layer 214, 314, 414 interposed between the outer surface 210, 310, 410 of the frame 202, 302, 402 and the outer liner 206, 306, 406. The inner primer layer 212, 312, 412 and the outer primer layer 214, 314, 414 are provided to improve adhesion between the inner surface 208, 308, 408 and the outer surface 210, 310, 410 of the frame 202, 302, 402, respectively, and the inner liner 204, 304, 404 and the outer liner 206, 306, 406.

[0026]

[0035] The inner liner 204, 304, 404 is made of a polymeric material. In one embodiment, the polymeric material is expanded polytetrafluoroethylene (ePTFE). The properties of ePTFE provide the inner liner 204, 304, 404 with a smooth, soft, and flexible inner surface for the sheath body 200, 300, 400, which reduces the risk of thrombus formation and reduces friction and stiction when inserting or removing a device through the expandable sheath. For example, the ePTFE inner liner 204, 304, 404 provides a low coefficient of friction surface when in contact with a device advanced through the sheath body, thereby reducing associated frictional forces. In the present disclosure, the outer liner 206, 306, 406 may be constructed of a single layer or multiple layers (e.g., a multi-layer liner) of polymeric material, as described in more detail below.

[0027]

[0036] Suitable primers for applying ePTFE liners to surfaces are well known and will not be detailed herein. As ePTFE is hydrophobic, suitable primers may take this into account. One example of a suitable primer is one that creates amine groups on the surface (e.g., co-deposition of polyethyleneimine (PEI) and polydopamine). Surface treatments such as plasma immersion and oxygen plasma have been used to create a suitable surface for ePTFE deposition. With reference to Figures 2-4, in a first embodiment, an ePTFE inner liner 204 is applied to the inner surface 208 of a braided frame 202, as described above. Alternatively, the frame 202 can be formed by patterning a hypotube having a lumen therein. In one embodiment, the hypotube is patterned by laser cutting. The pattern introduced into the hypotube is provided to control the axial expansion, radial expansion, and / or compression of the lumen.

[0028]

[0037] In the present embodiment of Figures 2-4, the outer liner 206 is also made of a polymeric material. The polymeric material used to form the outer liner 206 in this embodiment may be the same or different than the ePTFE inner liner 204 described above. In the illustrated embodiment, the outer liner 206 is made of thermoplastic polyurethane (TPU). The characteristics (or properties) of ePTFE and TPU advantageously provide the sheath body 200 with smooth, soft, and flexible inner and outer surfaces, respectively, reducing friction and stiction when inserting a device through or removing a device from the expandable sheath, thereby reducing the force required to insert and remove a device (e.g., an intracardiac heart pump) compared to the force required to insert and remove a device from a sheath body without a liner. Furthermore, the smooth surface of the TPU outer liner 206 advantageously reduces the risk of blood clots forming on the surface of the expandable sheath body 200. Furthermore, in some embodiments, an inner liner formed from ePTFE allows some liquid permeability through the liner, so that a liquid impermeable material can be selected for the outer layer. Such a construction may help reduce or eliminate unwanted leakage or weeping from the sheath body and aid in maintaining hemostasis. However, it should be understood that the introducer sheaths described herein are not limited to sheaths that include a liquid impermeable outer layer. For example, in some embodiments, a sheath that includes only an ePTFE inner liner may provide a sufficient degree of liquid impermeability to avoid leakage or weeping and maintain hemostasis during use.

[0029]

[0038] In further embodiments, the outer liner can have an outer layer (eg, TPU) layer that can be partially formed into the microporous structure of the ePTFE.

[0030]

[0039] 5-7, in a second embodiment, an ePTFE inner liner 304 is applied to the inner surface 308 of a braided frame 302, as described above. As with the first embodiment described above, alternatively, the frame 302 can be formed by patterning a hypotube having a lumen therein. The hypotube is patterned by laser cutting. The pattern introduced into the hypotube is provided to control the axial expansion, radial expansion, and compression of the lumen. The inner and outer surfaces of the frame 302 have an inner primer layer 312 and an outer primer layer 314 formed thereon.

[0031]

[0040] In this embodiment, the inner liner 304 and the outer liner 306 are made of the same material. For example, the inner liner 304 and the outer liner 306 are made of ePTFE. As in the first embodiment, the ePTFE characteristics advantageously provide the sheath body 300 with smooth, soft, and flexible inner and outer surfaces to reduce friction and stiction when inserting or removing a device through or from the expandable sheath, such that the force required to insert and remove a device (e.g., an intracardiac pump) is relatively less than the force required to insert and remove a device from a sheath body without a liner. Additionally, the smooth surface of the ePTFE outer liner 306 advantageously reduces the risk of thrombus formation on the surface of the expandable sheath body 300.

[0032]

[0041] 8-10, in a third embodiment, as described above, an ePTFE inner liner 404 is applied to the inner surface 408 of the braided frame 402. A primer layer 412 is interposed between the inner surface 408 of the frame 402 and the ePTFE inner liner 404. In this embodiment, the outer liner 406 has a multi-layer construction and is therefore made of multiple polymeric materials. In the illustrated embodiment, the outer liner 406 may have an ePTFE layer 416 and a TPU layer 418. As can be seen in FIGS. 9 and 10, the ePTFE layer 416 of the outer liner 406 is bonded to the outer surface 410 of the frame 402 (with a primer layer 414 interposed between the multi-layer outer liner 406 and the frame 402). The TPU layer 418 is applied over the ePTFE layer 416 to improve the biocompatibility of the ePTFE layer 416. As with the first and second embodiments, the ePTFE inner liner 404 and the outer multi-layer liner 406 advantageously provide smooth, soft, and flexible inner and outer surfaces, respectively, to the sheath body 400, reducing friction and stiction when inserting or removing a device through or from the expandable sheath, such that the force required to insert and remove a device (e.g., an intracardiac heart pump) is relatively less than the force required to insert and remove a device from a linerless sheath body. Additionally, the smooth surface of the multi-layer outer liner 406 advantageously reduces the risk of thrombus formation on the surface of the expandable sheath body 400.

[0033]

[0042] In the above-mentioned embodiment, the sheath body 200, 300, 400 may contain silicone oil impregnated into the ePTFE inner liner 204, 304, 404 to reduce or prevent air, water, and / or blood from penetrating the ePTFE inner liner 204, 304, 404. Silicone oil also reduces the coefficient of friction of the ePTFE. The coefficient of friction may be reduced by half. Silicone oil is introduced into the ePTFE liner by applying it to the surface that the ePTFE inner liner will contact. The silicone oil is then wicked up into the porous ePTFE. When silicone oil is applied to a surface to be wicked up into the ePTFE, the viscosity of the silicone oil is low enough that the silicone oil is wicked up into the ePTFE and is retained by the microporous structure of the hydrophobic ePTFE, providing a resilient lubricated surface. The ability of silicone oil to be retained in ePTFE is indirectly proportional to the density and pore size of ePTFE (i.e., a lower density ePTFE (i.e., a more porous ePTFE) requires a higher viscosity to exhibit similar silicone oil retention). To achieve the desired lubricating effect and obtain the desired retention of silicone oil, the viscosity of the silicone oil may be, for example, 350 cP for ePTFE with a density of about 0.4 g / cc. Viscosities above 350 cP do not provide the same lubricating effect. For example, a viscosity of 1000 cP provides only half the lubricating effect of a viscosity of 350 cP for ePTFE having a density of the order above.

[0034]

[0043] In the above-described embodiment, the inner liner 204, 304, 404 has a tubular shape and extends the entire length of the sheath body 200, 300, 400, as shown in Figures 2, 5, and 8. The outer liner 206, 306, 406 also has a tubular shape and extends the length of the elongated portion 201, 301, 401 of the sheath body 200, 300, 400. Thus, the outer liner 206, 306, 406 extends between the proximal end of the sheath body 200, 300, 400 and the split 203, 303, 403, where the outer surface of the sheath body 200, 300, 400 begins to taper in both the inner and outer diameters. As shown, the tapered section is followed by a smaller diameter section with constant inner and outer diameters. As shown, the outer liner 206, 306, 406 does not extend over the tapered portion and constant / smaller diameter.

[0035]

[0044] While the inner and outer diameters of the sheath body are primarily a matter of design choice, it is contemplated that the inner diameter of the primary sheath body is approximately 4 mm. About, as used herein, means plus or minus 25% of the stated value, or as one of ordinary skill in the art would so interpret the term in the appropriate context. The inner liner 204, 304, 404 and the outer liner 206, 306, 406 can have any suitable thickness. In one embodiment, the inner liner 204, 304, 404 and the outer liner 206, 306, 406 each have a thickness of approximately 0.05 mm. The lumen 205, 305, 405 of the sheath body 200, 300, 400 can be any suitable size. Preferably, the lumen 205, 305, 405 of the sheath body 200, 300, 400 has an inner diameter of 4 mm. The tapered portion 207, 307, 407 of the sheath body 200, 300, 400 may be of any suitable size. Preferably, the length of the tapered portion 207, 307, 407 is between 0.1 mm and 5 mm, and the diameter of the opening 209, 309, 409 at the distal end 211, 311, 411 of the tapered portion 207, 307, 407 is between about 3.7 mm and about 3.9 mm.

[0036]

[0045] Described herein is an introducer sheath assembly having a tubular frame having an internal lumen therein, the tubular frame being configured to temporarily expand from a first diameter to a second, larger diameter when a portion of a medical device having a diameter larger than the first diameter passes through the tubular frame; a liner adjacent an inner surface of the tubular frame, the liner being formed from expanded polytetrafluoroethylene (ePTFE); and a hub coupled to a proximal end of the tubular frame, the hub including a hemostasis valve.

[0037]

[0046] In one embodiment, the ePTFE liner is attached to the inner surface of the tubular frame. In a further embodiment, a primer is formed between the ePTFE liner and the inner surface of the lumen defined by the tubular frame. In another embodiment, an outer liner is formed on the outer surface of the tubular frame.

[0038]

[0047] The frame can be made of braided nitinol tubing and laser cut hypotubes. The outer liner can be made of a thermoplastic polyurethane, such as expanded polytetrafluoroethylene. In one embodiment, the outer liner is multi-layered. For example, the outer liner can have two layers, where a first layer can be formed on the outer surface of the frame and the first layer can be a thermoplastic polyurethane. A second layer of the two layers of the outer liner can be formed on top of the first layer, where the second layer includes expanded polytetrafluoroethylene.

[0039]

[0048] Also described herein is an expandable sheath body having a tubular frame having an internal lumen therein, the frame having gaps, the frame being expandable to a larger diameter and contractable to a smaller diameter and also flexible; an inner liner formed on a surface of the internal lumen defined by the tubular frame; and an outer liner formed on an outer surface of the frame.

[0040]

[0049] In one aspect, the sheath body can have a primer formed between an inner liner and a surface of a lumen defined by a tubular frame. A primer can also be formed between an outer liner and an outer surface of the frame. The frame can be a braided nitinol tube or a laser cut hypotube.

[0041]

[0050] In one embodiment of the sheath body, the inner liner may be made of expanded polytetrafluoroethylene, and the outer liner may be made of a thermoplastic polyurethane, such as expanded polytetrafluoroethylene.

[0042]

[0051] In a further embodiment, the outer liner may be multi-layered. For example, the outer liner may have two layers, where the first layer may be formed on the outer surface of the frame, and the first layer may be thermoplastic polyurethane. The second layer of the two layers of the outer liner may be formed on the first layer, and the second layer may be formed from expanded polytetrafluoroethylene.

[0043]

[0052] Described herein is an introducer sheath assembly having a tubular frame having an internal lumen therein, the tubular frame configured to temporarily expand from a first diameter to a second, larger diameter when a portion of a medical device having a diameter larger than the first diameter passes through the tubular frame. The introducer sheath has a liner adjacent an inner surface of the tubular frame, the liner being formed from expanded polytetrafluoroethylene (ePTFE), and a hub coupled to a proximal end of the tubular frame, the hub including a hemostasis valve.

[0044]

[0053] In one embodiment, the ePTFE liner is attached to the inner surface of the tubular frame. According to the above embodiment, a primer can be formed between the ePTFE liner and the inner surface of the lumen defined by the tubular frame. In any of the above embodiments, the outer liner is formed on the outer surface of the tubular frame. In any of the above embodiments, the frame is selected from the group consisting of braided nitinol tubing and laser cut hypotubes. The frame can be made of nitinol and the outer liner can be made of thermoplastic polyurethane or expanded polytetrafluoroethylene. In one embodiment, the outer liner is multi-layered. In another embodiment, the outer liner can have two layers, where a first layer is formed on the outer surface of the frame and the first layer comprises thermoplastic polyurethane. In a further embodiment, the second of the two layers of the outer liner is formed on the first layer and the second layer comprises expanded polytetrafluoroethylene.

[0045]

[0054] Also described herein is an expandable sheath body having a tubular frame having a lumen therein, the frame having a gap, the frame being expandable to a larger diameter and contractable to a smaller diameter, and also flexible. The sheath body can have an inner liner formed on a surface of the lumen defined by the tubular frame and an outer liner formed on an outer surface of the frame.

[0046]

[0055] In one embodiment, a primer is formed between the inner liner and a surface of the lumen defined by the tubular frame. In a further embodiment, a primer is formed between the outer liner and an outer surface of the frame. In the above embodiment, the expandable sheath body can have a frame made of braided Nitinol tubing or laser cut hypotube. In one embodiment, the frame is made of Nitinol. In the above embodiment, the expandable sheath body can have an inner liner made of expanded polytetrafluoroethylene. In the above embodiment, the outer liner can be made of thermoplastic polyurethane. According to the above embodiment, the outer liner can be made of expanded polytetrafluoroethylene. The outer liner can be multi-layered. In a further embodiment, the outer liner can have two layers, where a first layer is formed on the outer surface of the frame, and the first layer comprises thermoplastic polyurethane. In a further embodiment, a second layer of the two layers of the outer liner is formed on the first layer, and the second layer comprises expanded polytetrafluoroethylene.

[0047]

[0056] From the above and with reference to the various drawings, a person skilled in the art will appreciate that certain modifications may be made to the present disclosure without departing from the scope of the present disclosure. While several embodiments of the present disclosure are shown in the drawings, the disclosure is not intended to be limited thereto, but rather is intended to be as broad as the art will permit, and the specification is intended to be read in the same manner. Thus, the above description should not be construed as limiting, but merely as exemplifications of certain embodiments. A person skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

1. A tubular frame having a lumen inside, configured to temporarily expand from the first diameter to a second larger diameter when a portion of a medical device having a diameter larger than a first diameter passes through the tubular frame, A liner adjacent to the inner surface of the tubular frame, formed from expanded polytetrafluoroethylene (ePTFE), A hub connected to the proximal end of the tubular frame, the hub including a hemostatic valve An introducer sheath assembly, including the introducer sheath assembly.

2. The introducer sheath assembly according to claim 1, wherein the liner is attached to the inner surface of the tubular frame.

3. The introducer sheath assembly according to claim 1 or 2, wherein a primer is formed between the liner and the inner surface of the lumen defined by the tubular frame.

4. The introducer sheath assembly according to claim 1, wherein the outer liner is formed on the outer surface of the tubular frame.

5. The introducer sheath assembly according to claim 1, wherein the tubular frame is selected from the group consisting of braided nitinol tubing and laser-cut hypo tubing.

6. The introducer sheath assembly according to claim 1, wherein the tubular frame is made of nitinol.

7. The introducer sheath assembly according to claim 4, wherein the outer liner is made of thermoplastic polyurethane.

8. The introducer sheath assembly according to claim 4, wherein the outer liner is made of foamed polytetrafluoroethylene.

9. The introducer sheath assembly according to claim 4, wherein the outer liner is multilayered.

10. The introducer sheath assembly according to claim 4, wherein the outer liner comprises two layers, the first layer being formed on the outer surface of the tubular frame, and the first layer comprising thermoplastic polyurethane.

11. The introducer sheath assembly according to claim 10, wherein the second layer of the two layers of the outer liner is formed on the first layer, and the second layer comprises foamed polytetrafluoroethylene.

12. A tubular frame having a lumen inside, wherein the tubular frame has gaps, the tubular frame is expandable to a larger diameter, contractible to a smaller diameter, and is flexible, An inner liner formed on the surface of the lumen defined by the tubular frame, An outer liner formed on the outer surface of the tubular frame and Includes an expandable sheath body.

13. The expandable sheath body according to claim 12, wherein a primer is formed between the inner liner and the surface of the lumen defined by the tubular frame.

14. The expandable sheath body according to claim 12, wherein a primer is formed between the outer liner and the outer surface of the tubular frame.

15. The expandable sheath body according to claim 12, wherein the tubular frame is selected from the group consisting of braided nitinol tubing and laser-cut hypo tubing.

16. The expandable sheath body according to claim 15, wherein the tubular frame is made of nitinol.

17. The expandable sheath body according to claim 12, wherein the inner liner is made of foamed polytetrafluoroethylene.

18. The expandable sheath body according to claim 12, wherein the outer liner is made of thermoplastic polyurethane.

19. The expandable sheath body according to claim 12, wherein the outer liner is made of foamed polytetrafluoroethylene.

20. The expandable sheath body according to claim 12, wherein the outer liner is multilayered.

21. The expandable sheath body according to claim 20, wherein the outer liner comprises two layers, the first layer being formed on the outer surface of the tubular frame, and the first layer comprising thermoplastic polyurethane.

22. The expandable sheath body according to claim 21, wherein the second layer of the two layers of the outer liner is formed on the first layer, and the second layer comprises foamed polytetrafluoroethylene.

23. The expandable sheath body according to claim 17, wherein silicone oil is injected into the foamed polytetrafluoroethylene.

24. The expandable sheath body according to claim 23, wherein the silicone oil is injected into the foamed polytetrafluoroethylene by drawing up the silicone oil from the surface on which the foamed polytetrafluoroethylene layer is arranged.

25. The expandable sheath body according to claim 23, wherein the foamed polytetrafluoroethylene has a density of about 0.4 g / cc and the silicone oil has a viscosity of about 350 cP.

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