Expandable catheter sheath having an overlapping portion

Abstract

An expandable sheath for inserting an interventional medical device (e.g., an intracardiac heart pump) into a blood vessel. The sheath has an elongate body having a proximal end, a distal end, and a lumen (232) extending from the proximal end to the distal end. The sheath body has a first layer (240) which is a liner defining the lumen (232). The sheath body has a second layer (250) disposed on the first layer (240) and having a patterned structure. The sheath body has a third layer (260) disposed on the second layer (250). The sheath body includes a slit passing through the second and third layers (250, 260) extending along at least a portion of the sheath body. A first portion of the elongate sheath body overlaps a second portion of the sheath body along the slit, forming an overlap portion (280).

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0001] This application claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 346,226, filed May 26, 2022, which is incorporated herein by reference.

Background Art

[0002] Background

[0002] Interventional medical devices, such as intracardiac heart pump assemblies, can 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 placed within the heart, an intracardiac pump can pump blood from the left ventricle of the heart into the aorta or from the inferior vena cava into the pulmonary artery. The intracardiac pump can be driven by a motor (and associated drive cable) located outside the patient's body or an on - board motor located within the patient's body. Some intracardiac blood pump systems operate in parallel with the native heart, complement cardiac output, and can partially or fully relieve the load on the heart. Examples of such systems include the IMPELLA® device family (Abiomed, Inc., Danvers Mass.).

[0003]

[0003] In one approach, an intracardiac blood pump is inserted via a catheter procedure through the femoral artery using a sheath such as a peel - away introducer sheath. The sheath may alternatively be inserted at other locations, such as within the femoral vein or any pathway, for delivery of the pump to assist either the left or right side of the heart.

[0004]

[0004] The introducer sheath may be inserted into the femoral artery through an arteriotomy to form an insertion path for the pump assembly. Thereafter, a portion of the pump assembly is advanced into the artery through the lumen of the introducer sheath. The size required for the arteriotomy is a major concern. Thus, expandable introducer sheaths have been developed to reduce the size of the arteriotomy opening required to accommodate the sheath and the medical devices passed therethrough. Accordingly, further improvements to expandable introducer sheaths are continuously sought.

Summary of the Invention

Means for Solving the Problems

[0005] Summary

[0005] The systems, methods, and devices described herein provide an expandable sheath assembly for inserting an interventional medical device (e.g., an intracardiac heart pump) into a blood vessel through a vascular opening. The expandable sheath assembly includes a sheath body having a plurality of layers. The layers of the sheath body include a liner defining a lumen extending from a proximal end to a distal end of the sheath body, a patterned structure disposed over the liner, and a jacket or cover disposed over the patterned structure. The sheath body includes a slit extending through at least the patterned structure and the cover. In some embodiments, the liner also includes a slit. The slit extends from the distal end of the sheath body toward the proximal end of the sheath body. The sheath body is arranged such that a first portion of the sheath body along the slit overlaps a second portion of the sheath body along the slit, forming an overlap portion. In some embodiments, a seal is disposed over the cover to seal the slit of the sheath body. The arrangement of the sheath body of the present technology allows the sheath body to instantaneously expand radially as the interventional device passes through the lumen of the sheath in response to the radial tension generated as the interventional device passes through the lumen. When the interventional device is removed from the lumen, the sheath body automatically relaxes (i.e., radially contracts) and returns to its original state (or a state substantially the same as or close to the original state).

[0006]

[0006] In one aspect of the present technology, an expandable sheath is provided that includes an elongate sheath body having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end. The elongate sheath body includes a first layer, a second layer, and a third layer. The first layer is a liner that defines the lumen. The second layer is disposed over the first layer, and the second layer is a patterned structure. The third layer is disposed over the second layer. The elongate sheath body includes a slit that passes through the second layer and the third layer, and the slit extends along at least a portion of the elongate sheath body. A first portion of the elongate sheath body overlaps a second portion of the elongate sheath body along the slit, forming an overlap portion.

[0007]

[0007] In some aspects, the elongate sheath body is configured to radially expand from a non-expanded state to an expanded state to allow a portion of a medical device to pass through the lumen, and when the elongate sheath body is in the non-expanded state, the portion of the medical device has a cross-sectional area larger than the cross-sectional area of the lumen.

[0008]

[0008] In some aspects, the medical device is an intracardiac heart pump.

[0009]

[0009] In some aspects, when the elongate sheath body expands radially, the overlap between the first portion of the elongate sheath body and the second portion of the elongate sheath body decreases, thereby increasing the cross-sectional area of the lumen.

[0010]

[0010] In some aspects, when a portion of the medical device is removed from the lumen, the elongate sheath body is configured to relax such that the cross-sectional area of the lumen decreases and the elongate sheath body substantially returns to the cross-sectional area of the non-expanded state.

[0011]

[0011] In some aspects, the first layer is made of polytetrafluoroethylene (PTFE) or an elastomer.

[0012]

[0012] In some embodiments, the first layer includes a lubricious coating on the inner surface of the first layer.

[0013]

[0013] In some embodiments, the first layer includes a hydrophilic coating on the inner surface of the first layer.

[0014]

[0014] In some embodiments, the slit in the elongate sheath body further passes through the first layer.

[0015]

[0015] In some embodiments, the first layer includes a folded portion that extends along at least a portion of the elongate sheath.

[0016]

[0016] In some embodiments, in the cross-section of the first layer, the first layer is continuous and does not include any cuts around the first layer.

[0017]

[0017] In some embodiments, the second layer is made of metal.

[0018]

[0018] In some embodiments, the metal is stainless steel or nitinol.

[0019]

[0019] In some embodiments, the patterned structure is a coil.

[0020]

[0020] In some embodiments, the patterned structure is embedded within a third layer.

[0021]

[0021] In some embodiments, the third layer is made of a thermoplastic material.

[0022]

[0022] In some embodiments, the third layer is made of thermoplastic polyurethane (TPU) or polyether block amide.

[0023]

[0023] In some embodiments, the elongate sheath body is tubular.

[0024]

[0024] In some embodiments, the elongate sheath body further includes a fourth layer disposed over the third layer, and the fourth layer is configured to seal the folded portion of the elongate sheath body.

[0025]

[0025] In some embodiments, the fourth layer is made of an elastomer.

[0026]

[0026] In some embodiments, the fourth layer is made of TPU or silicone.

[0027]

[0027] In some embodiments, the expandable sheath further includes a hub, and the proximal end of the elongate sheath body is coupled to the hub.

Brief Description of the Drawings

[0028] Brief Description of the Drawings

Figure 1

[0028] A sheath assembly according to one aspect of the present technology is shown.

Figure 2

[0029] A radially expandable sheath assembly according to another aspect of the present technology is shown.

Figure 3

[0030] A longitudinal cross-sectional view of the sheath body of the sheath assembly of FIG. 2 taken along line A-A.

Figure 4

[0031] A cross-sectional view of the sheath body of the sheath assembly of FIG. 2 taken along line B-B.

Figure 5A

[0032] A perspective view of the sheath body of the sheath assembly of FIG. 2 according to one aspect of the present technology.

Figure 5B

[0033] A partial view of the distal end of the sheath body shown in FIG. 5A.

Figure 5C

[0033] A partial view of the distal end of the sheath body shown in FIG. 5A.

Figure 6A

[0034] A cross-sectional view of the sheath body of the sheath assembly of FIG. 2 taken along line B-B.

Figure 6B

[0034] Cross-sectional view of the sheath body of the sheath assembly of FIG. 2 along line B-B.

Figure 6C

[0034] Cross-sectional view of the sheath body of the sheath assembly of FIG. 2 along line B-B.

Figure 7

[0035] Cross-sectional view of the sheath body of the sheath assembly of FIG. 2 along line B-B.

Figure 8A

[0036] Perspective view of a radially expandable sheath body according to one aspect of the present technology.

Figure 8B

[0037] Side view of the radially expandable sheath body of FIG. 8A.

Figure 9

[0038] Side view of a radially expandable sheath body according to another aspect of the present technology.

Figure 10

[0039] Shows a method of manufacturing a radially expandable sheath assembly according to one aspect of the present technology.

Figure 11

[0040] Includes an illustration of a cross-sectional view of the sheath body of the sheath assembly of FIG. 2 along line B-B to show the steps of the method of FIG. 10 according to an aspect of the present technology.

Figure 12

[0041] Cross-sectional view of a sheath body according to another aspect of the present technology.

Figure 13

[0042] Longitudinal cross-sectional view of a sheath body according to another aspect of the present technology.

Mode for Carrying Out the Invention

[0029] Detailed Description

[0043] Aspects of the present disclosure will be described in detail with reference to the figures, where like or identical elements are denoted by the same reference numerals. It should be understood that the disclosed aspects are merely examples of the present disclosure, which can be embodied in various forms. Well-known functions or structures will not be described in detail so as not to obscure the present disclosure with unnecessary details. Accordingly, the specific structural and functional details disclosed herein should not be construed as limiting, but rather as a representative basis for the claims and for teaching those skilled in the art to utilize the present disclosure in substantially any appropriately detailed structure.

[0030]

[0044] To provide an overall understanding of the systems, methods, and devices described herein, an exemplary aspect will be described. The devices and features described herein are specifically described for use in connection with an intracardiac heart pump system, but all of the components and other features outlined below may be combined with one another in any suitable manner and may be adapted and applied to other types of medical devices such as electrophysiology testing and catheter ablation devices, angioplasty and stent placement devices, angiography catheters, peripherally inserted central venous catheters, central venous catheters, midline catheters, peripheral catheters, inferior vena cava filters, abdominal aortic aneurysm treatment devices, thrombus removal devices, TAVR delivery systems, heart treatment and heart assist devices including balloon pumps, heart assist devices implanted using a surgical incision, and other catheters and devices introduced based on other veins or arteries.

[0031]

[0045] As used herein, including in the claims, "tubular" does not necessarily mean having a circular cross-section. A tubular article may have, for example, an elliptical, polygonal, irregular, or other shaped cross-section.

[0032]

[0046] Commercially available peel-away introducer sheaths are not typically radially expandable, so the inner diameter of the introducer sheath must always be large enough to accommodate the largest diameter portion of the pump assembly, typically the pump head, even if other parts of the pump assembly, such as a catheter, have a significantly smaller diameter. In this example, the introducer sheath creates an opening with an outer diameter larger than necessary to pass the pump catheter into the blood vessel. The introducer sheath is then peeled or torn away and replaced with a lower profile repositioning sheath. There are several challenges associated with removing the introducer sheath by peeling. For example, the introducer may be torn too easily and / or prematurely, leading to bleeding or vascular complications. Some introducers may require excessive force to peel away and remove. If the physician applies excessive force, the physician may inadvertently move the position of the pump within the heart when the introducer is finally torn. Also, peel-away introducer sheaths complicate the design of the hemostatic valve located within the hub of the introducer, which also must be torn or separated by another means. Further, peel-away introducer sheaths create a larger vascular opening after the system is removed, which can complicate vascular closure.

[0033]

[0047] Medical introducers for uses other than inserting a heart pump have a radially expandable sheath body that can expand radially to allow a percutaneous device to pass through a patient's vasculature. These existing expandable introducers are for relatively short-term use and can be designed to prevent thrombosis between the sheath body and the indwelling catheter.

[0034]

[0048] These introducers have an inner diameter that is smaller than the outer diameter of the device being introduced therethrough when inserted. The introducer is expandable to enable passage of the device through the sheath into the vasculature. However, existing introducers have several drawbacks. For example, many currently available introducers require the user to interact with the sheath of the introducer, such as by inflating or actuating components, to expand the introducer, which adds steps to the introduction process. Further, while these introducers may be expandable, the sheaths of these introducers do not decrease in size or contract after expansion, or require manual intervention to cause such a decrease in size. Further, the sheaths of these introducers have insufficient smoothness of the outer shape. As a result, when these introducers are placed within a patient's vasculature, the rough outer edges of the sheath can lead to thrombus accumulation, potentially resulting in thrombosis or bleeding at the patient's arteriotomy during long-term use. Further, some of these sheaths may lack a structure that can adequately withstand kinking and buckling during typical anatomical bending conditions that occur during normal use of the introducer. In this regard, while these sheaths may allow for radial expansion, they do not allow for compression / expansion in the regions of the sheath not occupied by the device being passed therethrough, which can reduce kink resistance. Further, these sheaths may have issues with column strength, and particularly during removal of the device, axial buckling of the sheath can be a problem. Finally, currently available introducer sheaths may not be able to deliver large-diameter devices (i.e., devices that need to be passed through a sheath of a larger diameter) without requiring unacceptable insertion and removal forces to advance the device through the sheath.

[0035]

[0049] Accordingly, there remains a need for improved designs and performance of expandable introducer sheaths that can reduce or eliminate the drawbacks of current designs.

[0036]

[0050] The systems, methods, and devices described herein provide an expandable sheath assembly for inserting an interventional medical device (e.g., an intracardiac heart pump) into a blood vessel through a vascular opening. The expandable sheath assembly includes a sheath body having a plurality of layers. The layers of the sheath body include a liner defining a lumen extending from a proximal end to a distal end of the sheath body, a patterned structure disposed over the liner, and a jacket or cover disposed over the patterned structure. The sheath body includes a slit extending at least through the patterned structure and the cover. In some embodiments, the liner also includes a slit. The slit extends from the distal end of the sheath body toward the proximal end of the sheath body. The sheath body is arranged such that a first portion of the sheath body along the slit overlaps a second portion of the sheath body along the slit to form an overlap portion. A seal is disposed over the cover to seal the slit of the sheath body. The arrangement of the sheath body of the present technology enables the sheath body to instantaneously expand radially while the interventional device passes through the lumen of the sheath in response to the radial tension generated as the interventional device passes through the lumen. When the interventional device is removed from the lumen, the sheath body automatically relaxes (i.e., radially contracts) and returns to its original state (or a state substantially similar to or near its original state).

[0037]

[0051] Figure 1 shows a sheath assembly 100 according to an aspect of the present technology. The sheath assembly 100 includes a hub 110, a cap 120, a sheath body 130, a butterfly pad or suture pad 140, a side arm channel 160, and a stopcock 170. The hub 110 cooperates with the cap 120 to fix the sheath body 130 in a predetermined position. The hub 110 also has a detent 112 (only one of which is visible in FIG. 1) to assist in attaching the hub 110 to an introducer hub. The butterfly pad / suture pad 140 is configured to assist in attaching the sheath assembly 100 to a patient (e.g., by suturing the assembly to the patient). In this specification, the proximal end of the assembly 100 is at the hub / cap end, and the distal end of the assembly is at the tip of the sheath body 130. In this regard, the sheath body 130 includes a proximal end 102 and a distal end 104. The proximal end 102 of the sheath body 130 is attached to the hub 110. The sheath body 130 includes a lumen extending from the proximal end 102 to the distal end 104. The sheath body 130 is configured to allow a medical device inserted therein to pass through the hub 110.

[0038]

[0052] Fluid can be introduced into and / or withdrawn from the sheath assembly 100 via the side arm channel 160. The fluid flowing through the device can be controlled by the stopcock 170 (e.g., a three-way stopcock). A hemostatic valve (not shown) can also be included within the hub 110, and the hemostatic valve is configured to prevent blood leakage to the outside of the patient during insertion and / or removal of an intracardiac blood pump or other components. Any suitable hemostatic valve may be used, for example, as described and illustrated in U.S. Patent Application No. 17 / 097,582, filed November 13, 2020, and published as U.S. Patent Application Publication No. 2021 / 0146111. Further, in some implementations, the hub 110 can include a foam insert (not shown), and the foam insert is disposed proximal to the hemostatic valve and can be impregnated with a lubricant such as silicone so that components are lubricated as they are inserted through the foam into the sheath body 130.

[0039]

[0053] In one aspect, the lumen of the sheath body 130 may have a constant diameter. In this aspect, the diameter of the lumen should be large enough to accommodate the portion of the device having a large diameter that is inserted through the lumen, even if other portions of the inserted device have a significantly smaller diameter. For example, if the device being inserted is an intracardiac heart pump, the portion of the device having the largest diameter may be the pump and / or motor assembly, while other portions, such as the catheter of the pump, may have a significantly smaller diameter. Thus, in this case, the diameter of the lumen of the sheath body 130 must be large enough to accommodate the pump assembly of the intracardiac blood pump. Using a sheath body with a constant diameter, such as the sheath body 130, may cause the blood vessel opening to enlarge and the blood vessel closure to become complicated after the system is removed.

[0040]

[0054] Alternatively, a sheath assembly having a radially expandable sheath body according to aspects of the present technology may be provided. A sheath assembly having an expandable sheath is beneficial in a clinical environment to allow a physician to insert a large interventional device through a patient's vasculature without damaging the blood vessel. The expandable sheath body allows for the use of a sheath body having a reduced diameter (i.e., smaller than the largest portion of the device inserted into the lumen of the sheath body) relative to a sheath body of a certain diameter, while accommodating a larger interventional device by expanding during insertion. The expandable sheath body having a sufficiently small diameter may allow an operator to use commonly available medical instruments to close the hole in the patient's arteriotomy (made to allow insertion of the sheath assembly) after the sheath assembly has been removed from the patient. By allowing the use of such commonly available vascular closure devices, healthcare providers can use a wider range of medical instruments not limited to the types of instruments required to close a large diameter hole in the patient's arteriotomy. Further, by allowing a smaller arteriotomy, the expandable sheath according to the present disclosure may assist in reducing bleeding or other complications that may occur in procedures that require a larger introducer sheath.

[0041]

[0055] Referring to FIG. 2, a sheath assembly 200 is shown that includes a radially expandable sheath body 230 attached to a hub 110 according to aspects of the present technology. The sheath body 230 has a proximal end 202, a distal end 204, and a lumen 232 (shown in FIGS. 3 and 4) that extends from the proximal end 202 to the distal end 204. The sheath body 230 has an elongate tubular shape and extends distally from the hub 110 along a longitudinal axis 201. The proximal end 202 is coupled to the hub 110. As will be described in more detail below, the sheath body 230 is multi-layered and configured to radially expand from a non-expanded state to an expanded state to allow an interventional device, such as an intracardiac blood pump, to pass through the lumen 232, and then to return by reaction to the non-expanded state after the interventional device has passed through or has been removed from the lumen 232.

[0042]

[0056] For example, referring to FIGS. 3 and 4, cross-sectional views of the sheath body 230 along lines A-A and B-B (shown in FIG. 2), respectively, according to aspects of the present technology are shown. The sheath body 230 includes an inner liner 240 (first layer) that defines a lumen 232, a patterned structure 250 (second layer) disposed on the liner 240, and a cover or jacket 260 (third layer) disposed on the patterned structure 250 and the liner 240. In one aspect, as shown in FIG. 3, the patterned structure 250 is embedded within the cover 260 such that both the inner surface of the cover 260 and the inner surface of the patterned structure 250 contact the outer surface of the liner 240. It should be understood that the liner 240, the patterned structure 250, and the cover 260 are coaxially arranged relative to each other about the longitudinal axis 201.

[0043]

[0057] In one aspect, the liner 240 may have a smooth inner surface for lubricity and to facilitate the insertion of an intervention device, such as an intracardiac heart pump, through the lumen 232 with minimal friction, and may be made of a polymeric material such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy alkane (PFA), ethylene tetrafluoroethylene (ETFE), etc. In one aspect, the liner 240 may be made of an elastomer. In some aspects, the inner surface of the liner 240 may have a lubricious coating, such as a coating of a hydrophilic material, to further facilitate the delivery of an intervention device through the lumen 232.

[0044]

[0058] In one aspect, the patterned structure 250 is made of a metal wire. The metal can be stainless steel or nitinol. Alternatively, the patterned structure 250 can be made of a rigid material including other metals or non-metallic materials. The patterned structure 250 can include a wire made of metal (or non-metal) arranged in a coiled shape or in other suitable wire patterns such as braided or woven. The patterned structure 250 is configured to provide the sheath body 230 with a radial hoop strength that cancels out kinks during bending of the sheath body 230. The patterned structure 250 is also configured to provide structural rigidity to the sheath body 230. Further, the patterned structure 250 has appropriate elastic and shape memory properties that enable the sheath body 230 to expand radially instantaneously during insertion of the intervention device and to contract radially automatically when the intervention device is removed.

[0045]

[0059] In one aspect, the cover 260 is made of a polymer such as thermoplastic polyurethane (TPU) or polyether block amide, such as Pebax, Vestamid, etc. It should be understood that the cover 260 may be made of a thermoplastic elastomer or other types of thermoplastic materials. The cover 260 is configured to enclose the patterned structure 250 and provide additional column strength and kink resistance to the sheath body 230. It should be understood that the cover 260 is made of a material that is more flexible than the patterned structure 250. In one aspect, the cover 260 has a shore hardness in the range of 30 to 72D.

[0046]

[0060] In one aspect, a jacket or seal 270 is disposed on cover 260 to seal sheath body 230. For example, seal 270 can be made of an elastomer with a low durometer (e.g., about 10 to about 80 durometer on the Shore A scale), such as TPU, silicone, etc. Seal 270 can be made of a TPU such as Carbothane PC3575, or a silicone alternative such as silicone or Chronoprene T. As described below, in other aspects, it should be understood that sheath body 230 can be configured such that the sealing function of seal 270 can be provided by other components of sheath body 230 (e.g., liner 240), and seal 270 can be omitted from sheath body 230.

[0047]

[0061] As best shown in FIGS. 4 and 5A - 5C, in one aspect, sheath body 230 includes a longitudinal slit 234 that passes through liner 240, patterned structure 250, and thermoplastic cover 260, and slit 234 extends from distal end 204 towards proximal end 202. As described below, in another aspect, no slit is provided in liner 240, and longitudinal slit 234 is included only in patterned structure 250 and cover 260.

[0048]

[0062] As shown in FIG. 4, slit 234 separates the first longitudinal edge 282 from the second longitudinal edge 284 of sheath body 230.

[0049]

[0063] In one aspect, as shown in FIG. 5A, the slit 234 extends and terminates at the proximal end 202. In another aspect, the slit 234 terminates at a predetermined distance distal to the proximal end 202. In the aspect where the slit 234 terminates at a predetermined distance distal to the proximal end 202, there is a portion of the sheath body 230 at the proximal end 202 that does not have a slit. This proximal portion without the slit does not interact with the arteriotomy when the sheath body 230 is inserted into the patient and thus does not need to be crushed to a small diameter. The proximal portion of the sheath body 230 without the slit has a larger diameter than the portion of the sheath body 230 with the slit. Further, the proximal portion of the sheath body 230 without the slit enables attachment to the hub and assists in hemostasis at the patient's skin site.

[0050]

[0064] In any case, the sheath body 230 is coiled or folded upon itself along the slit 234 such that the diameter of the sheath body 230 decreases (relative to a sheath body having a non-overlapping, constant diameter). A first portion of the sheath body 230 along the slit 234 overlaps a second portion of the sheath body 230 along the slit 234, forming a longitudinal fold 280. In one aspect, a jacket or seal 270 is disposed on the cover 260 to seal the sheath body 230 and the slit 234 or the fold 280. As described above, the seal 270 can be made of an elastomer of low durometer (e.g., about 10 to about 80 durometer on the Shore A scale), such as TPU, silicone, etc., or other suitable materials. In one aspect, the seal 270 is made of a shrink wrap or shrink film. As shown in FIGS. 3 and 4, the seal 270 is disposed on the cover 260, encloses the cover 260, and extends longitudinally from the proximal end 202 to the distal end 204. The seal 270 seals the slit 234 and is configured to prevent blood or other fluid from leaking from the lumen 232 through the slit 234 or the fold 280, for example, when the sheath body 230 is inserted into the patient.

[0051]

[0065] In one aspect, the outer surface of the seal 270 has a lubricity additive formed therein or thereon to reduce the overall coefficient of friction of the sheath body 230 and to assist in the delivery of the sheath body 230 into and through the patient's vasculature. Further, both the outer surface of the seal 270 and the outer surface of the cover 260 are configured to be smooth to reduce thrombus formation or bleeding at the arteriotomy of the patient over long-term use of the sheath body 230 in the patient. The smooth outer surfaces of the seal 270 and the cover 260 also reduce the insertion / removal force required to insert the sheath body 230 into the patient's vasculature and to remove the sheath body 230 from the patient's vasculature.

[0052]

[0066] Due to the slotted arrangement, coiled arrangement, or overlapping arrangement of the sheath body 230, the sheath body 230 is flexible and can be radially expanded around the longitudinal axis 201 when a portion of an interventional device such as an intracardiac blood pump that is larger than the cross-sectional area of the lumen 232 when in the non-expanded state is introduced into the sheath body 210. For example, as shown in FIG. 4, before the interventional device is inserted into the lumen 232, the sheath body 230 is in a non-expanded or stationary state. In the non-expanded state, the lumen 232 has an inner diameter d and a first cross-sectional area. After a portion of the interventional device having a diameter larger than d or a cross-sectional area larger than the first cross-sectional area of the lumen 232 is inserted into the lumen 232, the overlapping portions of the sheath body 230 move away from each other as indicated by the arrows 238, 239 in FIG. 4, and the amount of overlap decreases. In this way, the sheath body 230 instantaneously expands radially to an expanded state to accommodate the larger dimensions of the inserted portion of the interventional device. In the expanded state, the lumen 232 has a diameter d' larger than d and a second cross-sectional area larger than the first cross-sectional area. It should be understood that the sheath body 230 is configured to expand radially locally along its longitudinal length as needed for the passage of different portions of the inserted interventional device until the interventional device passes through the lumen 232. After the interventional device exits the lumen 232, the sheath body 230 is configured to relax automatically (i.e., the overlapping portions of the sheath body 230 move towards each other and the amount of overlap increases).

[0053]

[0067] It should be understood that the ability of the sheath body 230 to relax from its expanded state after the interventional device is removed from the lumen 232 is determined at least in part by the material properties and shape / dimension properties of the patterned structure 250. Furthermore, this ability can also be provided by the material properties and shape / dimension properties of the cover 260 and the seal 270. For example, the elastic properties of the seal 270 and dimensions such as the inner diameter and wall thickness of the cover 260 and the seal 270 contribute to the ability of the sheath body 230 to relax from its expanded state.

[0054]

[0068] The design and material selection of the sheath body 230 are configured such that after the intervention device is removed, the sheath body 230 automatically returns to its non-expanded state, and it should also be understood that the cross-sectional area of the sheath body 230 is substantially the same as the original cross-sectional area of the sheath body 230 in the non-expanded state. In this context, "substantially the same" means that the sheath body 230 returns to a state where it has a diameter and cross-sectional area within 25% of each of the values of the diameter d and the first cross-sectional area that the sheath body 230 had in its original non-expanded state, respectively.

[0055]

[0069] Table 1 below includes exemplary ranges of dimensions (wall thickness and width) of the components or layers of the sheath body 230. Table 1 also includes exemplary dimensions that can be used for each layer within the corresponding ranges of components in one aspect of the sheath body 230.

[0056]

Table 1

[0057]

[0070] In one aspect, the liner 240 has no slit (i.e., the slit 234 does not extend through the liner 240). In the cross-sectional view of the liner 240, the liner 240 is continuous and does not include any breaks around the liner (i.e., the perimeter of the liner 240 forms a closed loop around the longitudinal axis 201 in the cross-sectional view). In this aspect, a portion of the liner 240 that extends longitudinally along the sheath body 230 is folded. For example, this aspect is shown in FIG. 12 according to the present technique. As shown in FIG. 12, in this aspect, the liner 240 has no slit and a portion of the liner 240 is folded over itself. In FIG. 12, it should be understood that the structures 250 and the cover 260 are shown as a single layer only for simplicity. The folded portion of the liner 240 and the slotted and overlapping arrangement of the patterned structure 250 and the cover 260 together enable the sheath body 230 to expand radially around the longitudinal axis 201. In this aspect, since the liner 240 has no slit and is continuous, the liner 240 is configured to seal the lumen 232. By the liner 240 providing a seal for the lumen 232, in this aspect, the sheath body 230 may not include a seal or cover 270. Alternatively, as shown in FIG. 12, the sheath body 230 may include a seal 270.

[0058]

[0071] In any of these aspects, the sheath assembly 200 including the sheath body 230 can be provided to a physician together with a dilator inserted into the lumen 232 of the sheath body 230 to facilitate smooth insertion of the sheath body 230 into a patient's vasculature. For example, after receiving the sheath assembly 200 and the dilator, the physician can flush the sheath body 230 through a side arm such as the side arm 160 of the sheath assembly. Thereafter, the dilator is inserted through the proximal end of the hub 110 (and the valve housed therein) and through the lumen 232 of the sheath body 230. The dilator has a diameter or cross-sectional area smaller than that of the sheath body 230, and thus it should be understood that when the dilator is inserted into the lumen 232, the sheath body 230 does not expand radially (and remains in a non-expanded state). Thereafter, the sheath body 230 is delivered into the patient's vasculature, and then the dilator is removed from the lumen 232. With the sheath body 230 deployed within the patient, an interventional device such as an intracardiac heart pump is inserted through the lumen 232. When the sheath body 230 is in a non-expanded state, if a portion of the interventional device includes a diameter or cross-sectional area larger than that of the lumen 232, the first longitudinal edge 282 and the second longitudinal edge 284 of the sheath body can advance in opposite radial directions. In other words, the first longitudinal edge 282 and the second longitudinal edge 284 of the sheath body can approach each other, and the overlapping portion of the sheath body 230 moves away from each other. As a result, the diameter or cross-sectional area of the lumen 232 locally increases as needed so that the sheath body 230 is in a (locally) expanded state to allow passage of the inserted interventional device. After the interventional device is removed from the lumen 232, the sheath body 230 relaxes (i.e., the overlapping portions of the sheath body 230 move towards each other), and the diameter or cross-sectional area of the lumen 232 decreases to a diameter substantially the same as the diameter d of the lumen 232 and the first cross-sectional area in the non-expanded state.

[0059]

[0072] In one aspect, the seal 270 can be fully joined (e.g., fully thermoformed or dispensed dipped) onto or outside the cover 260 such that the joining extends across the entire perimeter outside the cover 260. For illustrative purposes, such a full joining of the seal 270 to the cover 260 is shown in FIG. 6A. However, in other aspects, to reduce the distortion of the sheath body 230 during radial expansion and to enable easier delivery of an intervention device through the sheath body 230, the seal 270 can be selectively joined only to a portion of the perimeter of the cover 260 on the exact opposite side of the overlapping portion of the sheath body 230 (i.e., the side opposite the fold 280). In this regard, by not joining the seal 270 to the outside of the cover 260 along the overlapping portion of the sheath body 230, the overlapping edges of the sheath body 230 can separate and / or gather more easily and with less distortion, enabling easier radial expansion / contraction of the sheath body 230.

[0060]

[0073] For example, in FIG. 6B, the seal 270 is selectively joined (e.g., selectively thermoformed) to a predetermined portion 290 (e.g., 70%) of the outer perimeter of the cover 260 on the side opposite the overlapping portion of the sheath body 230. It should be understood that the predetermined portion 290 of the outer perimeter of the cover 260 joined to the seal 270 can include any percentage or ratio of the outer perimeter of the cover 260, such as 5%, 10%, 40%, 70%, 90%, etc., and can be selected to adjust the distortion, elasticity, and / or the force required to radially expand the sheath body 230. In one aspect, as shown in FIG. 6C, the seal 270 can be joined or tacked (e.g., using a UV curable adhesive, heat, a cyanoacrylate (CA) adhesive, etc.) only to a small region or point 291 (e.g., 0.1 - 5% of the outer perimeter of the cover 260) of the outer perimeter of the cover 260 on the side substantially opposite the overlapping portion of the sheath body 230.

[0061]

[0074] It should be understood that in some embodiments, the different layers (240, 250, 260) of the sheath body 230 may have different amounts of overlap. For example, as shown in FIG. 7, in one embodiment, the liner 240 and the cover 260 each have the same perimeter (measured from longitudinal edge 282 to longitudinal edge 284), and the patterned structure 250 has a perimeter smaller than the perimeters of the liner 240 and the cover 260. When the sheath body 230 is in the unexpanded state, as shown in FIG. 7, the overlapping portion of the liner 240 and the overlapping portion of the cover 260 may overlap by a predetermined amount a. In one embodiment, the sheath body 230 is configured to receive an intracardiac heart pump through the lumen 232. In this embodiment, when the sheath body 230 is in the unexpanded state, the overlap a is approximately (e.g., + / -25%) 6.3 mm. The overlap a can decrease to approximately (e.g., + / -25%) 1.3 mm when the largest part of the intracardiac blood pump is inserted through the lumen 232 and the sheath body 230 is in the expanded state. Thus, the circumferential expansion of the sheath body 230 in this embodiment is approximately (e.g., + / -25%) 5 mm. In this embodiment, the diameter of the lumen 232 in the unexpanded state is approximately (e.g., + / -25%) 3.5 mm, and the diameter of the lumen 232 in the expanded state is approximately (e.g., + / -25%) 5.1 mm.

[0062]

[0075] As shown in FIG. 7, in this embodiment, the patterned structure 250 has a perimeter smaller than the perimeters of the liner 240 and the cover 260. Thus, the longitudinal edges 282, 284 of the liner 240 and the cover 260 each extend or project circumferentially beyond the respective longitudinal edges 286, 288 of the patterned structure 250 by a predetermined amount c. In one embodiment, the predetermined amount c is approximately (e.g., + / -25%) 1 mm. When the sheath body 230 is in the unexpanded state, the overlapping portion of the patterned structure 250 may overlap by a predetermined amount b that is smaller than the overlap a between the overlapping portion of the liner 240 and the overlapping portion of the cover 260. In one embodiment, the overlap of the coils can be at least 1 mm.

[0063]

[0076] By selecting the predetermined overlap b to be smaller than the predetermined overlap a between the overlapping portion of the liner 240 and the overlapping portion of the cover 260, it should be understood that during normal use, the possibility of the end of the patterned structure 250 protruding or extending through the slit edge of the sheath body 230 is reduced. Further, when no slit is provided in the liner 240 (as described above), by selecting the overlap a to be larger than the overlap b, the amount of folding or overlapping of the folded portion of the liner 240 is increased, enabling a larger range of radial expansion and contraction of the sheath body 230.

[0064]

[0077] The predetermined overlap b of the patterned structure 250 when the sheath body 230 is in the non-expanded state enables the sheath body 230 to withstand kinking while also enabling the sheath body 230 to be flexible enough to be manipulated through the patient's vasculature during use during a procedure. Further, the predetermined overlap b can be selected such that there is still an overlap even when the sheath body 230 is in the expanded state. Thus, the overlap b enables the sheath body 230 to relax from the expanded state to a collapsed state. In this regard, if there is no overlap between the edges of the patterned structure 250, the edges of the slit may catch on each other, preventing the sheath body from returning to the collapsed state.

[0065]

[0078] In one aspect, as shown in FIG. 5A, the sheath body 230 may include a constant diameter or cross-sectional area from the proximal end 202 to the distal end 204 when in a relaxed and non-expanded state. In another aspect, the sheath body 230 may be configured to have a flared proximal end 202 when the sheath body 230 is in a relaxed and non-expanded state. For example, referring to FIGS. 8A and 8B, a radially expandable sheath body 330 according to one aspect of the present technology is shown. The sheath body 330 is configured to have the same features as the sheath body 230 (e.g., the multi-layer overlapping sheath body arrangement described above). However, in contrast to the sheath body 230, the sheath body 330 includes a proximal portion having a larger diameter and a larger cross-sectional area than the central and distal portions of the sheath body 330. In this regard, the proximal portion of the sheath body 330 may include a tapered portion 336 where the diameter of the sheath body 330 transitions from a first diameter to a second diameter, and the first diameter is smaller than the second diameter. The first diameter is the diameter of the central and distal portions of the sheath body 330, and the second diameter is the diameter of the proximal end 302 of the sheath body 330. The proximal end 302 may be coupled, overmolded, or mechanically attached to the hub 110.

[0066]

[0079] Referring back to FIG. 5A, in one aspect, the slit 234 extends linearly parallel to the axis 201 along the sheath body 230. In another aspect, the sheath body 230 may have a non-linear slit extending from the distal end 204 towards the proximal end 202, as shown in FIG. 9. Referring to FIG. 9, a sheath body 430 including a non-linearly extending slit 434 according to one aspect of the present technology is shown. It should be understood that the sheath body 430 is shown in FIG. 9 without a sealing layer (such as seal 270). It should also be understood that the sheath body 430 may include any of the features of the sheath bodies 230, 330 described above. However, the slit 434 of the sheath body 430 is rotated through the longitudinal length of the shaft body 430 such that the slit 434 extends from the distal end 404 of the sheath body 430 along a coiled or helical path around the longitudinal axis 401 towards the proximal end of the sheath body 430. The non-linearly extending slit 434 shown in FIG. 9 may increase the kink resistance of the sheath body 430. It should be understood that the non-linearly extending slit 434 may be selected as desired to adjust the kink characteristics and / or other operating characteristics of the sheath body 430. For example, in various aspects of the present technology, the pitch may be selected such that the non-linearly extending slit 434 has a predetermined number of turns or a portion of one turn (or multiple turns) through the longitudinal length of the sheath body 430. For example, the pitch may be selected such that the slit 434 may have multiple turns (i.e., two or more), as shown in FIG. 9. Alternatively, the pitch may be selected such that the slit 434 may have a single turn through the length of the sheath body 430. Alternatively, the pitch may be selected such that the slit 434 may rotate a portion of one turn (e.g., 0.1, 0.5, 0.8, etc.) or a portion of multiple turns (e.g., 1.2, 1.5, 2.3, etc.) through the length of the sheath body 430.

[0067]

[0080] Referring to FIG. 10, a method 1000 for manufacturing a reversibly radially expandable sheath body 230, 330, 430, etc., for use in a sheath assembly 100, 200, etc., according to one aspect of the present technology, is shown. In step 1002, a first material is disposed on a tubular heat-set mandrel in a predetermined pattern to form a patterned structure 250 on the heat-set mandrel. For example, as described above with respect to the patterned structure 250, the first material may be a metal wire such as nitinol or stainless steel wire. Further, the patterned structure 250 may be a coil or braid. In the case of a coil pattern, the metal wire is tightly wound in a coil around the heat-set mandrel. The heat-set mandrel has a first diameter. For example, in one aspect, the first diameter is 2.8 mm. In another aspect, the first diameter is 3.3 mm. However, it should be understood that other values of the first diameter may be used. In one aspect, the heat-set mandrel may be tapered from one diameter (e.g., 2.8 mm) to a larger outer diameter (e.g., 5 mm) to help prevent peeling at the inner diameter of the sheath body 230 after laminating the liner.

[0068]

[0081] In step 1004, heat is applied to the heat-set mandrel on which the patterned structure 250 is disposed to fix the shape of the patterned structure 250. For example, the heat-set mandrel having the patterned structure 250 may be placed in an oven at a predetermined temperature, such as 500 degrees Celsius, for a predetermined time, such as 9 minutes. It should be understood that the predetermined temperature and time are exemplary, and other temperatures and / or times may be used to change the properties of the patterned structure 250. For example, in one aspect, the predetermined temperature ranges from 450 to 550 °C, and the predetermined time ranges from 5 to 20 minutes.

[0069]

[0082] In step 1006, the patterned structure 250 is disposed on a laminated mandrel having a second diameter. In one aspect, the second diameter can be selected based on the maximum diameter of the intervention device that is inserted into the lumen 232 of the sheath body 230 when formed, and based on the necessary overlap required in the sheath body 230 to enable the sheath body to easily return from the expanded state to the collapsed state. For example, in one aspect, the intervention device is an intracardiac heart pump and the second diameter is 5.5 mm, which can thereby enable the insertion of the pump section of the intracardiac heart pump (i.e., the part of the pump having the maximum diameter). If the pattern of the patterned structure 250 is a coil, the patterned structure 250 is rewound on the laminated mandrel at a predetermined pitch. In one aspect, the pitch is 30 turns per inch, although other pitches may be selected.

[0070]

[0083] In step 1008, the patterned structure 250 is laminated with a cover material for the cover 260 and a liner material for the liner 240 such that the patterned structure 250 is disposed between the cover 260 and the liner 240 to form a multi-layered tubular sheath body such as the sheath body 230. The result of step 1008 is shown in FIG. 11 which shows a cross-sectional view of the sheath body 230 after step 1008 has been performed. As shown in FIG. 11, the cover 260, the patterned structure 250, and the liner 240 are formed such that the cover 260, the patterned structure 250, and the liner 240 are coaxially arranged, with the cover 260 forming the outermost layer and the liner 240 forming the innermost layer of the sheath body 230. It should be understood that in step 1008, the cover material can be extruded onto the liner material. Further, as described above and as shown in FIG. 3, the patterned structure 250 may be embedded in the cover 260. Further, the cover material may be a polymer such as TPU or polyether block amide, and the liner material may be a lubricious material such as PTFE.

[0071]

[0084] In procedure 1010, a longitudinal slit 234 is cut along the sheath body 230 from the distal end 204 towards the proximal end 202. It should be understood that the slit 234 may terminate at a predetermined distance in front of the proximal end 202. In one aspect, the predetermined distance is 3.4 cm. In one aspect, the slit may terminate in or immediately before the tapered proximal portion of the sheath body 230 (e.g., as shown in FIG. 6). The result of procedure 1010 is shown in FIG. 11, which shows a cross-sectional view of the sheath body 230 after procedure 1010 has been performed.

[0072]

[0085] (As described above and as shown in FIG. 12) In another aspect of method 1000 in which no slit can be made in the liner 240, as shown in FIG. 10, procedure 1008 is interchanged with procedure 1009. In procedure 1009, the patterned structure is laminated onto the cover material. In one aspect, procedure 1009 can be performed in two sub-procedures. In the first sub-procedure, a first layer of the cover material is laminated onto the mandrel, and in the second sub-procedure, the patterned structure 250 is added and a second layer of the cover material is laminated onto the patterned structure 250 on the side opposite the first layer of the cover material. Referring to FIG. 13, a cross-sectional view of the sheath body 230 having the characteristics of this aspect according to the present technology is shown. As shown, in this aspect, the cover includes first and second layers 261, 262, and the patterned structure 250 is embedded between the cover layer 261 and the cover layer 262. Thus, the patterned structure 250 is encapsulated on all sides by the layers 261, 262 of the cover material (which together form the cover layer 260).

[0073]

[0086] Thereafter, in step 1010, a slit is made along the sheath body in the patterned structure and the cover material, and in step 1011, the liner is laminated inside the sheath body. In one aspect, for step 1011, mandrels or masking materials of different sizes can be used to laminate the liner material inside the sheath body to prevent the cover material from being undesirably formed when the cover material is reheated. For example, in this aspect, after the slit is made in the patterned structure 250 and the cover material, when the patterned structure 250 and the cover material are laminated on the inner liner layer, the lamination is performed on a mandrel having a diameter smaller than the mandrel used in step 1009. The purpose of the small-diameter mandrel is to enable the slit sheath body to be formed into a desired shape in step 1011. With this small mandrel, during this lamination process, the cover material can be formed or bonded to itself, thereby preventing the wound sheath from expanding when completed. To prevent this from occurring, the dimensions of the inner liner layer and the mandrel are selected to allow an overlap of the inner liner layer to prevent the cover layer from contacting itself when the sheath body is wound. Alternatively, masking techniques may be used to prevent such contact.

[0074]

[0087] In any aspect of method 1000, in step 1012, the sheath body 230 is coiled around its inner side such that a first portion of the sheath body 230 extending along slit 234 overlaps a second portion of the sheath body 230 extending along slit 234, forming a longitudinal overlap portion. If no slit is made in the liner 240 (i.e., step 1009 is performed), it should be understood that in step 1012, a portion of the liner 240 extending along the longitudinal length of the sheath body is folded to overlap. In any case, after the slit is made in the sheath body 230, the patterning structure is configured to apply a coiling force to the sheath body 230 to coil the sheath body 230 around its inner side. In step 1014, a seal 270 configured to seal slit 234 is formed, and a sealing material (e.g., an elastomer) is applied onto the cover 260 to prevent fluid such as blood from leaking from the lumen 232 through slit 234 when the sheath body 230 is inserted into a patient's vasculature. The results of steps 1012 and 1014 (when a slit is made in the liner 240) are shown in FIG. 11, which shows a cross-sectional view of the sheath body 230 after steps 1012 and 1014. In one aspect, step 1012 includes shrink-wrapping the sealing material on the cover 260. In step 1016, the proximal end 202 of the sheath body 230 is attached to a sheath hub such as hub 110 to form an expandable sheath assembly such as sheath assembly 200.

[0075]

[0088] In another aspect, method 1000 may also include an additional step in which, before applying the sealing material (step 1014) and attaching the hub (step 1016), the sheath body 230 is re-laminated onto a tapered mandrel and re-heated to form the proximal end.

[0076]

[0089] In this step, the cover material is attached to the sheath body. The cover material can be attached to the proximal and distal ends of the sheath body, or along the entire length of the sheath. The cover material can be attached to the sheath body in its coiled form, or by expanding the sheath over a larger mandrel. Alternatively, an additional step can be performed of heating the sheath body 230 on a mandrel of a larger diameter to enable the cover to enclose the patterned structure 250.

[0077]

[0090] The coiled design of the sheath bodies 230, 330, 430 and the method 1000 of manufacturing them provide many advantages over existing sheath assemblies and reduce or eliminate many of the disadvantages associated with the existing sheath assemblies described above. For example, the seal 270 is configured to seal the slit 234 along the sheath body 230 and prevent bleeding / thrombosis during long-term use of the sheath assembly 200 within a patient. Further, the sheath body 230 utilizes the patterned structure 250 to increase the amount of kink resistance relative to existing sheath assembly designs and provide excellent column strength. The increased kink resistance aids in a safer procedure. The use of the folded configuration and the patterned structure 250 enables the sheath body 230 to expand radially to an expanded state without the need for an actuating mechanism manually operated by the user, and also to automatically spring back to a state substantially similar to its original non-expanded state. Further, the folded configuration enables the sheath body 230 to have a reduced diameter relative to a sheath body of a constant diameter. Still further, the proposed design of the sheath body 230 is easily manufacturable.

[0078]

[0091] In one aspect of the present technology, an expandable sheath is provided that includes an elongate sheath body having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end. The elongate sheath body includes a first layer, a second layer, and a third layer. The first layer is a liner that defines the lumen. The second layer is disposed over the first layer, and the second layer is a patterned structure. The third layer is disposed over the second layer. The elongate sheath body includes a slit that passes through the second layer and the third layer, and the slit extends along at least a portion of the elongate sheath body. A first portion of the elongate sheath body overlaps a second portion of the elongate sheath body along the slit, forming an overlap portion.

[0079]

[0092] In some aspects, the elongate sheath body is configured to radially expand from a non-expanded state to an expanded state to allow a portion of a medical device to pass through the lumen, and when the elongate sheath body is in the non-expanded state, the portion of the medical device has a cross-sectional area that is larger than the cross-sectional area of the lumen.

[0080]

[0093] In some aspects, the medical device is an intracardiac heart pump.

[0081]

[0094] In some aspects, when the elongate sheath body radially expands, the overlap between the first portion of the elongate sheath body and the second portion of the elongate sheath body decreases, thereby increasing the cross-sectional area of the lumen.

[0082]

[0095] In some aspects, when a portion of the medical device is removed from the lumen, the elongate sheath body is configured to relax such that the cross-sectional area of the lumen decreases and the elongate sheath body substantially returns to the cross-sectional area of the non-expanded state.

[0083]

[0096] In some aspects, the first layer is made of polytetrafluoroethylene (PTFE) or an elastomer.

[0084]

[0097] In some embodiments, the first layer includes a lubricious coating on the inner surface of the first layer.

[0085]

[0098] In some embodiments, the first layer includes a hydrophilic coating on the inner surface of the first layer.

[0086]

[0099] In some embodiments, the slit of the elongate sheath body further passes through the first layer.

[0087]

[0100] In some embodiments, the first layer includes a folded portion that extends along at least a portion of the elongate sheath.

[0088]

[0101] In some embodiments, in the cross-section of the first layer, the first layer is continuous and does not include any cuts around the first layer.

[0089]

[0102] In some embodiments, the second layer is made of metal.

[0090]

[0103] In some embodiments, the metal is stainless steel or nitinol.

[0091]

[0104] In some embodiments, the patterned structure is a coil.

[0092]

[0105] In some embodiments, the patterned structure is embedded within a third layer.

[0093]

[0106] In some embodiments, the third layer is made of a thermoplastic material.

[0094]

[0107] In some embodiments, the third layer is made of thermoplastic polyurethane (TPU) or polyether block amide.

[0095]

[0108] In some embodiments, the elongate sheath body is tubular.

[0096]

[0109] In some embodiments, the elongate sheath body further includes a fourth layer disposed over the third layer, and the fourth layer is configured to seal the overlapping portion of the elongate sheath body.

[0097]

[0110] In some embodiments, the fourth layer is made of an elastomer.

[0098]

[0111] In some embodiments, the fourth layer is made of TPU or silicone.

[0099]

[0112] In some embodiments, the expandable sheath further includes a hub, and the proximal end of the elongate sheath body is coupled to the hub.

[0100]

[0113] From the above and by referring to the various drawings, those skilled in the art will understand that specific changes can be made to the present disclosure without departing from the scope of the present disclosure. Although some embodiments of the present disclosure are shown in the drawings, the present disclosure is not intended to be limited thereto, but is intended to have a wide range acceptable in the art, and the present specification should also be interpreted as such. Therefore, the above description should not be construed as limiting, but should be construed merely as an exemplification of specific embodiments. Those skilled in the art will envision other changes within the scope and spirit of the appended claims.

Claims

1. A long sheath body having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end, comprising, wherein the long sheath body is a first layer, and the first layer is a liner defining the lumen, a first layer; a second layer disposed on the first layer, and the second layer is a patterned structure, a second layer; a third layer disposed on the second layer; comprising, the long sheath body includes a slit passing through the second layer and the third layer, and the slit extends along at least a portion of the long sheath body, a first portion of the long sheath body overlaps a second portion of the long sheath body along the slit to form an overlapping portion; an expandable sheath.

2. The long sheath body is configured to expand radially from a non-expanded state to an expanded state to enable a portion of a medical device to pass through the lumen, and when the long sheath body is in the non-expanded state, the portion of the medical device has a cross-sectional area larger than the cross-sectional area of the lumen. The expandable sheath according to claim 1.

3. The medical device is an intracardiac heart pump. The expandable sheath according to claim 2.

4. When the long sheath body expands radially, the overlap between the first portion of the long sheath body and the second portion of the long sheath body decreases, whereby the cross-sectional area of the lumen increases. The expandable sheath according to claim 2 or 3.

5. When the portion of the medical device is removed from the lumen, the long sheath body is configured to relax such that the cross-sectional area of the lumen decreases and the long sheath body substantially returns to the cross-sectional area in the non-expanded state. The expandable sheath according to any one of claims 2 to 4.

6. The first layer is made of polytetrafluoroethylene (PTFE) or an elastomer. The expandable sheath according to any one of claims 1 to 5.

7. The first layer includes a lubricious coating on the inner surface of the first layer. The expandable sheath according to any one of claims 1 to 6.

8. The expandable sheath according to any one of claims 1 to 7, wherein the first layer includes a hydrophilic coating on the inner surface of the first layer.

9. The expandable sheath according to any one of claims 1 to 8, wherein the slit of the elongate sheath body further passes through the first layer.

10. The expandable sheath according to any one of claims 1 to 8, wherein the first layer includes a folded portion extending along at least a part of the elongate sheath.

11. The expandable sheath according to claim 10, wherein in the cross section of the first layer, the first layer is continuous and does not include any cut around the first layer.

12. The expandable sheath according to any one of claims 1 to 11, wherein the second layer is made of metal.

13. The expandable sheath according to claim 12, wherein the metal is stainless steel or nitinol.

14. The expandable sheath according to any one of claims 1 to 13, wherein the patterned structure is a coil.

15. The expandable sheath according to any one of claims 1 to 13, wherein the patterned structure is embedded in the third layer.

16. The expandable sheath according to any one of claims 1 to 15, wherein the third layer is made of a thermoplastic material.

17. The expandable sheath according to any one of claims 1 to 16, wherein the third layer is made of thermoplastic polyurethane (TPU) or polyether block amide.

18. The expandable sheath according to any one of claims 1 to 17, wherein the elongate sheath body is tubular.

19. The expandable sheath according to any one of claims 1 to 18, wherein the elongate sheath body further includes a fourth layer disposed on the third layer, and the fourth layer is configured to seal the folded portion of the elongate sheath body.

20. The expandable sheath according to claim 19, wherein the fourth layer is made of an elastomer.

21. The expandable sheath according to claim 19, wherein the fourth layer is made of TPU or silicone.

22. The expandable sheath according to any one of claims 1 to 21, further including a hub, wherein the proximal end of the elongate sheath body is coupled to the hub.

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