Expandable catheter sheath with fold

Abstract

An expandable sheath for inserting an interventional medical device, such as an intracardiac heart pump, into a blood vessel. The sheath has an elongate sheath 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) that is a liner defining a lumen (232). The sheath has a second layer (250) disposed on the first layer (240) and being a patterned structure. The sheath has a third layer (260) disposed on a second layer (250). The sheath includes a slit through the second layer (250) and the third layer (260), the slit extending along at least a portion of the sheath. The first portion of the elongate sheath overlaps with the second portion of the sheath along the slit to form a fold (280).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 346,226, filed on May 26, 2022, which is incorporated herein by reference. Background Art

[0003] An interventional medical device, such as an intracardiac heart pump assembly, may be introduced into the heart surgically or percutaneously 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, an intracardiac pump may pump blood from the left ventricle of the heart into the aorta, or pump blood from the inferior vena cava into the pulmonary artery. An intracardiac pump may be powered by a motor (and accompanying drive cable) located outside the patient's body or by an autonomous motor located inside the patient. Some intracardiac blood pump systems can operate in parallel with the native heart to supplement cardiac output and partially or completely offload the demands placed on the heart. Examples of such systems include Series equipment (Abiomed In., Danvers Mass.).

[0004] In one method, the intracardiac blood pump is inserted through the femoral artery using a sheath (such as a peel-away introducer sheath) via catheterization. The sheath may alternatively be inserted into other locations, such as the femoral vein or any route for delivering a pump to support the left or right side of the heart.

[0005] An introducer sheath may be inserted through an arteriotomy into the femoral artery, creating an insertion path for the pump assembly. A portion of the pump assembly is then advanced through the lumen of the introducer sheath and into the artery. The necessary size of the arteriotomy is a very significant issue. As a result, expandable introducer sheaths have been developed so that a smaller arteriotomy opening is required to accommodate the sheath and the medical device passed therethrough. Thus, improvements in expandable introducer sheaths continue to be sought. Summary of the invention

[0006] 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 blood vessel hole. The expandable sheath assembly includes a sheath having multiple layers. The layers of the sheath include a liner defining a lumen extending from the proximal end of the sheath to the distal end, a patterned structure disposed on the liner, and a sheath or covering disposed on the patterned structure. The sheath includes a slit that passes through at least the patterned structure and the covering. In some aspects, the liner also has a slit. The slit extends from the distal end of the sheath to the proximal end of the sheath. The sheath is arranged so that the sheath overlaps the second part of the sheath along the slit to form a fold. In some aspects, a seal is disposed on the covering to seal the slit of the sheath. The arrangement of the sheath of the present technology enables the sheath to expand radially instantaneously in response to the radial tension caused by the interventional device passing through the lumen of the sheath during the passage of the interventional device through the lumen of the sheath. After removing the interventional device from the lumen, the sheath automatically relaxes (i.e., radially contracts) to return to an original state (or a state substantially similar or close to the original state).

[0007] In one aspect of the present technology, an expandable sheath is provided, comprising an elongated sheath body having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end. The elongated sheath body comprises a first layer, a second layer, and a third layer. The first layer is a lining defining the lumen. The second layer is disposed on the first layer, and the second layer is a patterned structure. The third layer is disposed on the second layer. The elongated sheath body comprises a slit passing through the second layer and the third layer, wherein the slit extends along at least a portion of the elongated sheath body. The first portion of the elongated sheath body overlaps with the second portion of the elongated sheath body along the slit to form a fold.

[0008] In some aspects, the elongated sheath is configured to radially expand from an unexpanded state to an expanded state to allow a portion of the medical device to pass through the lumen, and when the elongated sheath is in the unexpanded state, the cross-sectional area of ​​the portion of the medical device is greater than the cross-sectional area of ​​the lumen.

[0009] In some aspects, the medical device is an intracardiac heart pump.

[0010] In some aspects, when the elongated sheath body is radially expanded, the overlap between the first portion of the elongated sheath body and the second portion of the elongated sheath body is reduced such that the cross-sectional area of ​​the lumen is increased.

[0011] In some aspects, the elongate sheath is configured to relax when a portion of the medical device is removed from the lumen such that the transverse cross-sectional area of ​​the lumen is reduced and the elongate sheath substantially returns to the cross-sectional area of ​​the unexpanded state.

[0012] In some aspects, the first layer is made of polytetrafluoroethylene (PTFE) or an elastomer.

[0013] In some aspects, the first layer includes a lubricious coating on an interior surface of the first layer.

[0014] In some aspects, the first layer includes a hydrophilic coating on an interior surface of the first layer.

[0015] In some aspects, the slit of the elongated sheath further extends through the first layer.

[0016] In some aspects, the first layer includes a folded portion extending along at least a portion of the elongated sheath.

[0017] In some aspects, in a cross-section of the first layer, the first layer is continuous and does not include any breaks in a circumference of the first layer.

[0018] In some aspects, the second layer is made of metal.

[0019] In some aspects, the metal is stainless steel or nitinol.

[0020] In some aspects, the patterned structure is a coil.

[0021] In some aspects, the patterned structure is embedded within the third layer.

[0022] In some aspects, the third layer is made of thermoplastic.

[0023] In some aspects, the third layer is made of thermoplastic polyurethane (TPU) or polyether blockamid.

[0024] In some aspects, the elongated sheath is tubular.

[0025] In some aspects, the elongated sheath further includes a fourth layer disposed on the third layer, the fourth layer configured to seal the folds in the elongated sheath.

[0026] In some aspects, the fourth layer is made of an elastomer.

[0027] In some aspects, the fourth layer is made of TPU or polysiloxane.

[0028] In some aspects, the expandable sheath further comprises a hub, wherein the proximal end of the elongated sheath body is coupled to the hub. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A sheath assembly according to one aspect of the present technology is shown.

[0030] Figure 2

[0013] A radially expandable sheath assembly in accordance with another aspect of the present technology is shown.

[0031] Figure 3 yes Figure 2 Longitudinal section of the sheath body of the sheath assembly along line AA.

[0032] Figure 4 yes Figure 2 A cross section of the sheath body of the sheath assembly along line BB.

[0033] Figure 5A According to one aspect of the present technology Figure 2 A perspective view of the sheath body of the sheath assembly.

[0034] Figure 5B and 5C yes Figure 5A A partial view of the distal end of the sheath is shown.

[0035] Figures 6A-6C yes Figure 2 A cross section of the sheath body of the sheath assembly along line BB.

[0036] Figure 7 yes Figure 2 A cross section of the sheath body of the sheath assembly along line BB.

[0037] Fig. 8A is a perspective view of a radially expandable sheath according to one aspect of the present technology.

[0038] Figure 8B yes Fig. 8A Side view of a radially expandable sheath.

[0039] Fig. 9 is a side view of a radially expandable sheath according to another aspect of the present technology.

[0040] Fig.10 A method of making a radially expandable sheath assembly according to one aspect of the present technology is shown.

[0041] Fig.11 include Figure 2 FIG. 1 is a diagram of a cross-sectional view of a sheath body of a sheath assembly along line BB to illustrate the Fig.10 steps in the method.

[0042] Fig.12 is a cross-section of a sheath according to another aspect of the present technology.

[0043] Fig.13 is a longitudinal cross-section of a sheath according to another aspect of the present technology. DETAILED DESCRIPTION

[0044] Various aspects of the present disclosure are described in detail with reference to the accompanying drawings, wherein like reference numerals represent 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. In order to avoid obscuring the present disclosure with unnecessary detail, well-known functions or configurations are not described in detail. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but only as a basis for the claims and as a representative basis for teaching those skilled in the art to use the present disclosure in various ways in almost any appropriately detailed structure.

[0045] In order to fully understand the systems, methods, and devices described herein, certain illustrative aspects will be described. Although the devices and features thereof described herein are specifically described for use in conjunction with an intracardiac heart pump system, it should be understood that all of the components and other features outlined below may be combined with one another in any suitable manner and may be applicable to other types of medical devices, such as electrophysiology research and catheter ablation devices, angioplasty and stent implantation devices, angiographic catheters, peripherally inserted central catheters, central venous catheters, midline catheters, peripheral catheters, inferior vena cava filters, abdominal aortic aneurysm treatment devices, thrombectomy devices, TAVR delivery systems, cardiac therapy and cardiac assist devices (including balloon pumps), cardiac assist devices implanted using surgical incisions, and any other venous or arterial based introduction catheters and devices.

[0046] As used herein, including in the claims, "tubular" does not necessarily mean having a circular cross-section. For example, a tubular article may have an elliptical, polygonal, irregular, or other shaped cross-section.

[0047] Since commercially available removable 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, typically the pump head, even if the other parts of the pump assembly (such as the catheter) are much smaller in diameter. In this instance, the introducer sheath creates an opening with an outer diameter wider than the outer diameter required to allow the pump catheter to enter the blood vessel. The introducer sheath is then peeled off or removed and replaced with a reset sheath of a smaller profile. Removing the introducer sheath by peeling off the introducer sheath brings several challenges. For example, the introducer may tear too easily and / or prematurely, leading to bleeding or vascular complications. Some introducers may require excessive force to peel off for removal. If the surgeon uses too much force, when the introducer eventually tears, the surgeon may inadvertently change the position of the pump in the heart. The peelable introducer sheath also complicates the design of the hemostatic valve located in the hub of the introducer, which also needs to be torn or otherwise separated. In addition, after removing the system, the peelable introducer sheath will result in a larger vascular opening, which may complicate vascular closure.

[0048] Medical introducers for applications other than insertion of heart pumps have an expandable sheath that can be radially expanded to allow percutaneous device access to the patient's vasculature. These existing expandable introducers are intended for relatively short-term use and may be designed to prevent thrombosis between the sheath and the indwelling catheter.

[0049] The inner diameter of these introducers when inserted is smaller than the outer diameter of the device to be introduced therein. The introducers are expandable to allow the device to enter the vascular system through the sheath. However, existing introducers have several disadvantages. For example, many currently available introducers require the user to interact with the sheath of the introducer to expand the introducer, such as by inflating or activating a component, which increases the steps of the introduction process. In addition, although these introducers may be expandable, the sheaths in these introducers do not reduce in size or shrink after expansion, or require manual intervention to reduce in size. In addition, the sheaths of these introducers include poor external geometric smoothness. Therefore, when these introducers are placed in the patient's vascular system, thrombosis or bleeding may occur at the patient's arteriotomy during long-term use due to the rough outer edge of the sheath that may cause thrombus accumulation. Further, some of these sheaths may lack structures that fully resist kinking and buckling under typical anatomical bending conditions that occur during conventional use of the introducer. In this regard, these sheaths can allow radial expansion, but do not allow sheath compression / expansion in areas of the sheath that are not occupied by the device passing through, which may reduce kink resistance. Additionally, these sheaths may have column strength issues, and axial buckling of the sheath may be an issue, particularly during device removal. Finally, by design, currently available introducer sheaths may not be able to deliver large-bore devices (i.e., devices that require insertion through a larger diameter sheath) without requiring unacceptable insertion and removal forces to advance the device through the sheath.

[0050] Accordingly, improvements in the design and performance of expandable introducer sheaths that may reduce or eliminate the deficiencies of current designs continue to be sought.

[0051] 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 hole. The expandable sheath assembly includes a sheath having multiple layers. The layers of the sheath include a liner defining a lumen extending from the proximal end of the sheath to the distal end, a patterned structure disposed on the liner, and a sheath or covering disposed on the patterned structure. The sheath includes a slit that passes through at least the patterned structure and the covering. In some aspects, the liner also has a slit. The slit extends from the distal end of the sheath to the proximal end of the sheath. The sheath is arranged so that the sheath overlaps the second part of the sheath along the slit to form a fold. A seal is disposed on the covering to seal the slit of the sheath. The arrangement of the sheath of the present technology enables the sheath to expand radially instantaneously in response to the radial tension caused by the interventional device passing through the lumen of the sheath during the passage of the interventional device through the lumen of the sheath. After removing the interventional device from the lumen, the sheath will automatically relax (i.e., radially contract) and return to the original state (or a state substantially similar or close to the original state).

[0052] Figure 1 A sheath assembly 100 according to various aspects of the present technology is shown. The sheath assembly 100 has a hub 110, a cover 120, a sheath body 130, a butterfly pad or suture pad 140, a side arm channel 160, and a stopcock 170. The hub 110 works in conjunction with the cover 120 to secure the sheath body 130 in place. The hub 110 also has a detent 112 ( Figure 1 104). 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 via the hub 110 to pass therethrough.

[0053] Fluid can be introduced into the sheath assembly 100 and / or withdrawn from the sheath assembly 100 through the side arm channel 160. The flow of fluid through the device can be controlled by a stopcock 170 (e.g., a three-way stopcock). A hemostatic valve (not shown) may also be included in the hub 110, the hemostatic valve being configured to prevent blood from leaking outside the patient during insertion and / or removal of an intracardiac blood pump or other components. Although any suitable hemostatic valve may be used, an example is described and illustrated in U.S. patent application No. 17 / 097,582, filed on November 13, 2020 and published as US2021 / 0146111. In addition, in some embodiments, the hub 110 may include a foam insert (not shown) placed proximal to the hemostatic valve, which may be soaked with a lubricant such as silicone to lubricate the component as it is inserted into the foam and enters the sheath body 130.

[0054] In one aspect, the lumen of sheath 130 can have a fixed diameter. In this regard, the diameter of the lumen should be large enough to accommodate the large diameter portion of the device inserted therein, even if other portions of the inserted device have significantly smaller diameters. For example, when the inserted device is an intracardiac heart pump, the largest diameter portion of the device may be the pump and / or motor assembly, while other portions, such as the catheter of the pump, may be much smaller in diameter. Therefore, in this case, the lumen diameter of sheath 130 must be large enough to accommodate the pump assembly of the intracardiac blood pump. Use of a fixed diameter sheath (such as sheath 130) can result in a large vessel opening after the system is removed, which can complicate vessel closure.

[0055] Optionally, according to various aspects of the present technology, a sheath assembly with a radially expandable sheath body can be provided. A sheath assembly with an expandable sheath is useful in a clinical setting, allowing a surgeon to insert a large interventional device through the patient's vascular system without damaging the blood vessel. An expandable sheath body allows the use of a sheath body that is reduced in diameter relative to a fixed diameter sheath body (i.e., smaller than the largest portion of the device inserted into the sheath body lumen), while accommodating a larger interventional device by expanding during insertion. An expandable sheath body with a sufficiently small diameter can allow a practitioner to use a commonly used medical device to close the hole in the patient's arteriotomy (the hole is made to allow the insertion of the sheath assembly) after the sheath assembly is removed from the patient's body. By allowing the use of this commonly used vascular closure device, a medical practitioner can use a wider range of medical devices, which are not limited to the device category required for closing a larger diameter hole in the patient's arteriotomy. In addition, by allowing a smaller arteriotomy, an expandable sheath according to the present disclosure can help reduce bleeding or other complications that may occur in an operation requiring a larger introducer sheath.

[0056] Reference Figure 2According to various aspects of the present technology, a sheath assembly 200 including a radially expandable sheath body 230 is attached to a hub 110. The sheath body 230 has a proximal end 202, a distal end 204, and a lumen 232 (eg, Figure 3 and Figure 4 201 ). The sheath 230 has an elongated tubular shape and extends distally from the hub 110 along the longitudinal axis 201. The proximal end 202 is coupled to the hub 110. As will be described in more detail below, the sheath 230 is multi-layered and is configured to radially expand from an unexpanded state to an expanded state to allow an interventional device (such as an intracardiac blood pump) to pass through the lumen 232, and then reel back to the unexpanded state after the interventional device has been passed through or removed from the lumen 232.

[0057] For example, refer to Figure 3 and Figure 4 , according to various aspects of the present technology, respectively along lines AA and BB (such as Figure 2 ) shows a cross-sectional view of the sheath 230. The sheath 230 includes an inner lining 240 (first layer) defining a lumen 232, a patterned structure 250 (second layer) disposed on the lining 240, and a cover or sheath 260 (third layer) disposed over the patterned structure 250 and the lining 240. In one aspect, as Figure 3 As shown, patterned structure 250 is embedded within cover 260 such that the inner surfaces of cover 260 and patterned structure 250 both contact the outer surface of liner 240. It should be understood that liner 240, patterned structure 250, and cover 260 are coaxially arranged relative to each other about longitudinal axis 201.

[0058] In one aspect, the liner 240 can have a smooth inner surface and be made of a polymer material, such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), ethylene tetrafluoroethylene (ETFE), etc., to obtain lubricity and facilitate insertion of an interventional device (e.g., an intracardiac heart pump) through the lumen 232 with minimal friction. In one aspect, the liner 240 can be made of an elastomer. In some aspects, the inner surface of the liner 240 can have a lubricious coating (e.g., a hydrophilic material coating) to further facilitate delivery of an interventional wire device through the lumen 232.

[0059] In one aspect, the patterned structure 250 is made of metal wire. The metal can be stainless steel or nitinol. Alternatively, the patterned structure 250 can be made of other metals or rigid materials including non-metallic materials. The patterned structure 250 can include a wire made of metal (or non-metal), which is curled or arranged with other suitable line patterns (such as fabrics or braids). The patterned structure 250 is configured to provide radial hoop strength to the sheath body 230, which offsets the kink during the bending of the sheath body 230. The patterned structure 250 is also configured to provide structural rigidity to the sheath body 230. In addition, the patterned structure 250 has suitable elasticity and shape memory properties, which enables the sheath body 230 to expand radially instantaneously during the insertion of the interventional device and automatically contract radially when taken out.

[0060] In one aspect, the cover 260 is made of a polymer, such as a thermoplastic polyurethane (TPU) or a polyether block amide, such as PEBAX, Vestamid, etc. It should be understood that the cover 260 can be made of a thermoplastic elastomer or other types of thermoplastics. The cover 260 is configured to encapsulate the patterned structure 250 and provide additional column strength and kink resistance to the sheath 230. It should be understood that the cover 260 is made of a softer material than the patterned structure 250. In one aspect, the Shore hardness of the cover 260 is in the range of 30-72D.

[0061] In one aspect, a sheath or seal 270 is disposed on the cover 260 to seal the sheath 230. For example, the seal 270 can be made of a low durometer (e.g., about 10 to about 80 durometer on the Shore A scale) elastomer, such as TPU, polysiloxane, etc. The seal 270 can be made of TPU (e.g., Carbothane PC3575) or polysiloxane or a polysiloxane substitute (e.g., Chronoprene T). As described below, it should be understood that in other aspects, the sheath 230 is configured such that the sealing features of the seal 270 can be provided by other components of the sheath 230 (e.g., the liner 240), and the seal 270 can be omitted from the sheath 230.

[0062] like Figure 4 and 5A -5C, in one aspect, the sheath 230 includes a longitudinal slit 234 passing through the liner 240, the patterned structure 250, and the thermoplastic cover 260, wherein the slit 234 extends from the distal end 204 toward the proximal end 202. As described below, in another aspect, the liner 240 is not cut, and the longitudinal slit 234 only passes through the patterned structure 250 and the cover 260.

[0063] like Figure 4 As shown, the slit 234 separates a first longitudinal edge 282 from a second longitudinal edge 284 of the sheath 230 .

[0064] In one aspect, the slit 234 extends to and terminates at the proximal end 202, such as Figure 5A As shown. On the other hand, the slit 234 terminates a predetermined distance distal to the proximal end 202. In the aspect where the slit 234 terminates a predetermined distance distal to the proximal end 202, the sheath 230 has a portion at the proximal end 202 without a slit. When the sheath 230 is inserted into the patient's body, the non-slit proximal portion does not interact with the arteriotomy and therefore does not need to be contracted to a smaller diameter. The non-slit proximal portion of the sheath 230 has a larger diameter than the slit portion of the sheath 230. In addition, the non-slit proximal portion of the sheath 230 can be attached to the hub and facilitate hemostasis at the patient's skin site.

[0065] In either case, the sheath 230 is curled or overlapped along the slit 234 such that the diameter of the sheath 230 is reduced (relative to a non-overlapping, fixed diameter sheath), and a first portion of the sheath 230 along the slit 234 overlaps a second portion of the sheath 230 along the slit 234 to form a longitudinal fold 280. In one aspect, a sheath or seal 270 is disposed on the cover 260 to seal the sheath 230 and the slit 234 or fold 280. As described above, the seal 270 can be made of a low durometer (e.g., about 10 to about 80 durometer on the Shore A scale) elastomer (e.g., TPU, silicone, etc.) or other suitable material. In one aspect, the seal 270 is made of shrink wrap or shrink film. As Figure 3 and 4 As shown, seal 270 is disposed above and around cover 260 and extends longitudinally from proximal end 202 to distal end 204. Seal 270 is configured to seal slit 234 and prevent blood or other fluids from leaking from lumen 232 through slit 234 or fold 280, for example, when sheath 230 is inserted into a patient.

[0066] In one aspect, the outer surface of the seal 270 has a lubricating additive formed therein or thereon to reduce the overall coefficient of friction of the sheath 230 and facilitate delivery of the sheath 230 into and through the patient's vasculature. In addition, the outer surfaces of the seal 270 and the cover 260 are configured to be smooth to reduce thrombosis or bleeding at the patient's arteriotomy during the patient's long-term use of the sheath 230. The smooth outer surfaces of the seal 270 and the cover 260 also reduce the insertion / removal force required to insert and remove the sheath 230 from the patient's vasculature.

[0067] The slits or curls or overlapping arrangement of the sheath 230 make the sheath 230 flexible and capable of radial expansion about 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 in the unexpanded state is introduced into the sheath 230. For example, Figure 4 As shown, before the interventional device is inserted into the lumen 232, the sheath 230 is in an unexpanded or static state. In the unexpanded 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 greater than the diameter d or a cross-sectional area greater than the first cross-sectional area of ​​the lumen 232 is inserted into the lumen 232, the overlapping portion of the sheath 230 will be as shown in FIG. Figure 4 As shown in the arrows 238 and 239 in the figure, the sheath body 230 moves away from each other, and the overlap will be reduced. In this way, the sheath body 230 instantly expands radially to an expanded state to accommodate the larger size of the insertion portion of the interventional device. In the expanded state, the diameter d' of the lumen 232 is greater than the diameter d, and the second cross-sectional area is greater than the first cross-sectional area. It should be understood that the sheath body 230 is configured to locally expand radially along the longitudinal length according to the need for the different parts of the inserted interventional device to pass until the interventional device passes through the lumen 232. After the interventional device leaves the lumen 232, the sheath body 230 is configured to relax automatically (i.e., the overlapping portions of the sheath body 130 move toward each other and the overlap increases).

[0068] It should be appreciated that the ability of the sheath 230 to relax from its expanded state after the interventional device is removed from the lumen 232 is determined at least in part based on the material properties and shape / size properties of the patterned structure 250. In addition, this ability may also be provided by the material properties and shape / size properties of the covering 260 and the seal 270. For example, the elastic properties of the seal 270 and the dimensions such as the inner diameter and wall thickness of the covering 260 and the seal 270 facilitate the relaxation of the sheath 230 from its expanded state.

[0069] It should also be understood that the design and material selection of the sheath 230 are configured such that after the interventional device is removed, the sheath 230 automatically returns to its unexpanded state, wherein the cross-sectional area of ​​the sheath 230 is substantially similar to the original cross-sectional area of ​​the sheath 230 in the unexpanded state. In this context, "substantially similar" means that the sheath 230 returns to a state where the diameter and cross-sectional area are within 25% of the respective values ​​of the diameter d and the first cross-sectional area of ​​the sheath 230 in the original unexpanded state.

[0070] Table 1 below includes exemplary ranges of dimensions (wall thickness and width) for components or layers of the sheath 230. Table 1 also includes exemplary dimensions for each layer within the corresponding ranges of components that may be used for one aspect of the sheath 230.

[0071] Table 1

[0072]

[0073] In one aspect, the liner 240 is not cut (i.e., the slit 234 does not extend through the liner 240), and in the cross section of the liner 240, the liner 240 is continuous without any breaks in the circumference of the liner (i.e., the circumference of the liner 240 forms a closed loop around the longitudinal axis 201 in the cross section). In this aspect, the portion of the liner 240 extending longitudinally along the sheath 230 is folded. For example, according to the present technology, Fig.12 This aspect is shown in FIG. Fig.12 As shown, in this aspect, the liner 240 is not cut open and portions of the liner 240 are folded over on themselves. Fig.12 2, the structure 250 and the covering 260 are shown as a single layer for simplicity only. The folded portions of the liner 240 and the slits and overlapping arrangement of the patterned structure 250 and the covering 260 together enable the sheath 230 to radially expand about the longitudinal axis 201. In the present aspect, because the liner 240 is free of slits and is continuous, the liner 240 is configured to seal the lumen 232. In the case where the liner 240 provides a seal for the lumen 232, in the present aspect, the sheath 230 may not include a seal or covering 270. Optionally, as shown in FIG. Fig.12 As shown, the sheath 230 may include a seal 270 .

[0074] In any of these aspects, the sheath assembly 200 including the sheath body 230 can provide the surgeon with a dilator inserted into the lumen 232 of the sheath body 230 to facilitate smooth insertion of the sheath body 230 into the patient's vascular system. For example, after receiving the sheath assembly 200 and the dilator, the surgeon can flush the sheath body 230 through the side arm (such as the side arm 160) of the sheath assembly. The dilator is then inserted through the proximal end of the hub 110 (and the valve contained therein) and the lumen 232 of the sheath body 230. It should be understood that the diameter or cross-sectional area of ​​the dilator is smaller than the sheath body 230, so when the dilator is inserted into the lumen 232, the sheath body 230 will not expand radially (and remain in an unexpanded state). The sheath body 230 is then delivered to the patient's vascular system, and the dilator is then removed from the lumen 232. With the sheath body 230 deployed in the patient, an interventional device, such as an intracardiac heart pump, is inserted through the lumen 232. When the sheath 230 is in an unexpanded state, if the portion of the interventional device includes a larger diameter or cross-sectional area than the lumen 232, the first longitudinal edge 282 and the second longitudinal edge 284 of the sheath can be advanced in opposite radial directions. In other words, the first longitudinal edge 282 and the second longitudinal edge 284 of the sheath can move closer, and the overlapping portions of the sheath 230 will be away from each other. Therefore, the diameter or cross-sectional area of ​​the lumen 232 will be locally increased as required, so that the sheath 230 (locally) is in an expanded state to allow the inserted interventional device to pass. After the interventional device is removed from the lumen 232, the sheath 230 is relaxed (i.e., the overlapping portions of the sheath 130 move toward each other), and the diameter or cross-sectional area of ​​the lumen 232 is reduced to a diameter substantially similar to the diameter d and the first cross-sectional area of ​​the lumen 232 in the unexpanded state.

[0075] In one aspect, the seal 270 can be fully bonded (e.g., fully thermoformed or dispensed) on or over the exterior of the cover 260 such that the bond extends around the entire circumference of the exterior of the cover 260. For illustrative purposes, Fig. 6A 280 to the covering 260. However, in other aspects, the seal 270 can be selectively bonded to only a portion of the circumference of the covering 260 that is located on the diametrically opposite side of the overlapping portion of the sheath 230 (i.e., opposite the fold 280) to reduce the strain on the sheath 230 during radial expansion and allow for easier delivery of interventional devices through the sheath 230. In this regard, by not bonding the seal 270 to the exterior of the covering 260 along the overlapping portion of the sheath 230, the overlapping edges of the sheath 230 can separate and / or come together more easily and with less strain, thereby making it easier for the sheath 230 to expand / contract radially.

[0076] For example, in Figure 6BIn the embodiment of the present invention, the seal 270 is selectively bonded (e.g., selectively thermoformed) to a predetermined portion 290 (e.g., 70%) of the periphery of the cover 260 that is opposite to the overlapping portion of the sheath 230. It should be understood that the predetermined portion 290 of the periphery of the cover 260 bonded to the seal 270 can be any percentage or proportion of the periphery of the cover 260, such as 5%, 10%, 40%, 70%, 90%, etc., and can be selected to adjust the strain, elasticity and / or force required to radially expand the sheath 230. In one aspect, as Figure 6C As shown, the seal 270 can be bonded or attached (e.g., using UV curable glue, heat, cyanoacrylate (CA) adhesive, etc.) only to a small area or point 291 of the periphery of the cover 260 (e.g., 0.1-5% of the periphery of the cover 260) that is approximately opposite to the overlapping portion of the sheath 230.

[0077] It should be appreciated that in some aspects, different layers (240, 250, 260) of the sheath 230 may have different amounts of overlap. Figure 7 As shown, in one aspect, the liner 240 and the cover 260 each have the same circumference (measured from the longitudinal edge 282 to the longitudinal edge 284, and the circumference of the patterned structure 250 is smaller than the circumference of the liner 240 and the cover 260. When the sheath 230 is in an unexpanded state, as shown in FIG. Figure 7 As shown, the overlapping portions of the liner 240 and the cover 260 can overlap by a predetermined amount a. In one aspect, the sheath 230 is configured to receive an intracardiac heart pump through the lumen 232. In this aspect, when the sheath 230 is in an unexpanded state, the overlap a is about (e.g., + / - 25%) 6.3 mm. When the largest portion of the intracardiac blood pump is inserted through the lumen 232 and the sheath 230 is in an expanded state, the overlap a can be reduced to about (e.g., + / - 25%) 1.3 mm. Thus, in this aspect, the circumferential expansion of the sheath 230 is about (e.g., + / - 25%) 5 mm. In this aspect, in the unexpanded state, the diameter of the lumen 232 is about (e.g., + / - 25%) 3.5 mm, and the size of the lumen 232 in the expanded state is about (e.g., + / - 25%) 5.1 mm.

[0078] like Figure 7As shown, in the present aspect, the perimeter of the patterned structure 250 is less than the perimeter of the liner 240 and the cover 260. Thus, the longitudinal edges 282, 284 of the liner 240 and the cover 260 protrude or extend circumferentially beyond each longitudinal edge 286, 288 of the patterned structure 250, respectively, by a predetermined amount c. In one aspect, the predetermined amount c is about (e.g., + / - 25%) 1 mm. When the sheath 230 is in an unexpanded state, the overlapping portions of the patterned structure 250 can overlap by a predetermined amount b that is less than the overlap a between the overlapping portions of the liner 240 and the cover 260. In one aspect, the overlap of the coils can be at least 1 mm.

[0079] It should be understood that by selecting the predetermined overlap b to be less than the predetermined overlap a between the overlapping portions of the liners 240 and 260, the likelihood that the ends of the patterned structure 250 protrude or extend through the slit edge of the sheath 230 during normal use is reduced. In addition, when the liner 240 is not cut (as described above), by selecting the overlap a to be greater than the overlap b, the amount of folding or overlapping of the folded portion of the liner 240 is increased, which allows the sheath 230 to have a greater range of radial expansion and contraction.

[0080] It should be understood that when the sheath 230 is in an unexpanded state, the predetermined overlap b in the patterned structure 250 enables the sheath 230 to resist kinking while also allowing the sheath 230 to be flexible enough to pass through the patient's vascular system when used during surgery. In addition, the predetermined overlap b can be further selected so that there is an overlap even when the sheath 230 is in an expanded state. Therefore, the overlap b enables the sheath 230 to relax from the expanded state to the contracted state. In this regard, if there is no overlap between the edges of the patterned structure 250, the edges of the slits may get stuck to each other and prevent the sheath from returning to the contracted state.

[0081] In one aspect, Figure 5A As shown, when in a relaxed and unexpanded state, the sheath 230 can include a constant diameter or cross-sectional area from the proximal end 202 to the distal end 204. On the other hand, when the sheath 230 is in a relaxed and unexpanded state, the sheath 230 can be configured with an expanded proximal end 202. For example, referring to Fig. 8A and 8B, a radially expandable sheath 330 is shown according to aspects of the present technology. The sheath 330 is configured with the same features as the sheath 230 (e.g., the multiple layers of overlapping sheath arrangement described above). However, compared to the sheath 230, the diameter and cross-sectional area of ​​the proximal portion of the sheath 330 are larger than the central and distal portions of the sheath 330. In this regard, the proximal portion of the sheath 330 may include a tapered portion 336 that transitions the sheath 330 from a first diameter to a second diameter, wherein the first diameter is less than the second diameter. The first diameter is the diameter of the central and distal portions of the sheath 330, and the second diameter is the diameter of the proximal end 302 of the sheath 330. The proximal end 302 may be bonded, overmolded, or mechanically attached to the hub 110.

[0082] Reference again Figure 5A In one aspect, the slit 234 extends linearly along the sheath 230 parallel to the axis 201. In another aspect, as Fig. 9 As shown, the sheath 230 may have a nonlinear slit extending from the distal end 204 toward the proximal end 202. Fig. 9 , according to aspects of the present technology, a sheath 430 including a non-linearly extending slit 434 is shown. It should be understood that Fig. 9 The sheath 430 shown in FIG. 4 does not have a sealing layer (such as seal 270). It should also be understood that the sheath 430 includes any of the features of the sheaths 230, 330 described above. However, the slit 434 of the sheath 430 is rotated along the longitudinal length of the sheath 430 so that the slit 434 extends from the distal end 404 of the sheath 430 along a coil or spiral path around the longitudinal axis 401 toward the proximal end of the sheath 430. Fig. 9 The nonlinearly extending slits 434 shown in FIG. 4 can increase the kink resistance of the sheath 430. It should be understood that the nonlinearly extending slits 434 can be selected as desired to adjust the kinking and / or other operating characteristics of the sheath 430. For example, in various aspects of the present technology, the pitch can be selected so that the nonlinearly extending slits 434 have a predetermined number of turns or a portion of a number of turns along the longitudinal length of the sheath 430. For example, the pitch can be selected so that the slits 434 can have multiple turns (i.e., 2 or more), such as Fig. 9 Optionally, the pitch can be selected so that the slits 434 can have a single turn over the entire length of the sheath 430. Optionally, the pitch can be selected so that the slits 434 can rotate a fraction of a turn (e.g., 0.1, 0.5, 0.8, etc.) or a fraction of multiple turns (e.g., 1.2, 1.5, 2.3, etc.) over the length of the sheath 430.

[0083] Reference Fig.10, a method 1000 for manufacturing a reversibly radially expandable sheath (such as sheath 230, 330, 430) for use in a sheath assembly (such as sheath assemblies 100, 200) is presented according to aspects of the present technology. In step 1002, a first material is arranged on a tubular heat-setting mandrel in a predetermined pattern to form a patterned structure 250 on the heat-setting mandrel. For example, as described above with reference to the patterned structure 250, the first material can be a metal wire, such as nitinol or stainless steel wire. In addition, the patterned structure 250 can be a coil or a braid. In the case of a coil pattern, the metal wire is tightly wound around the heat-setting mandrel. The heat-setting 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 can be used. In one aspect, the heat set mandrel can taper from one diameter (eg, 2.8 mm) to a larger outer diameter (eg, 5 mm) to help prevent delamination on the inner diameter of the sheath 230 after the liner is laminated.

[0084] In step 1004, heat is applied to the heat-setting mandrel having the patterned structure 250 disposed thereon to set the patterned structure 250. For example, the heat-setting mandrel having the patterned structure 250 may be placed in an oven at a predetermined temperature (e.g., 500 degrees Celsius) for a predetermined time (e.g., 9 minutes). It should be understood that the predetermined temperature and time are exemplary, and other temperatures and / or times may also be used to change the properties of the patterned structure 250. For example, in one aspect, the predetermined temperature is in the range of 450-550°C, and the predetermined time is in the range of 5-20 minutes.

[0085] In step 1006, the patterned structure 250 is arranged on a laminated mandrel having a second diameter. In one aspect, the second diameter can be selected based on the maximum diameter of the interventional device 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 allow the sheath body to easily recover from an expanded state to a contracted state. For example, in one aspect, the interventional device is an intracardiac heart pump, and the second diameter is 5.5mm, which can be inserted into the pump section (i.e., the largest diameter part of the pump) of the intracardiac heart water pump. If the pattern of the patterned structure 250 is a coil, the patterned structure 250 is rewound onto the laminated mandrel at a predetermined pitch. In one aspect, the pitch is 30 turns per inch, but other pitches can also be selected.

[0086] 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-layer tubular sheath, such as the sheath 230 . Fig.11The result of step 1008 is shown in FIG. 1 , which shows a cross-sectional view of the sheath 230 after performing step 1008. Fig.11 As shown, the cover 260, the patterned structure 250 and the liner 240 are formed so that the cover 260, the patterned structure 250 and the liner 240 are coaxially arranged, the cover 260 forms the outermost layer of the sheath 230, and the liner 240 forms the innermost layer of the sheath 230. It should be understood that in step 1008, the cover material can be extruded onto the liner material. In addition, as described above and Figure 3 As shown, patterned structure 250 may be embedded in cover 260. In addition, the cover material may be a polymer (such as TPU or polyether block amide), and the lining material may be a lubricating material (such as PTFE).

[0087] In step 1010, a slit 234 is cut longitudinally along the sheath 230 from the distal end 204 toward the proximal end 202. It should be understood that the slit 234 can terminate a predetermined distance before the proximal end 202. In one aspect, the predetermined distance is 3.4 cm. In one aspect, the slit can terminate at or before the tapered proximal portion of the sheath 230 (e.g., as shown in FIG. 6 ). Fig.11 The result of step 1010 is shown in , which shows a cross-sectional view of the sheath body 230 after performing step 1010.

[0088] In another aspect of method 1000, liner 240 is not cut (as described above and Fig.12 As shown), step 1008 is replaced by step 1009, such as Fig.10 As shown. In step 1009, the patterned structure is laminated onto the cover material. In one aspect, step 1009 can be performed in two sub-steps. In the first sub-step, a first layer of cover material is laminated onto the mandrel, and in the second sub-step, the patterned structure 250 is added and a second layer of cover material is laminated onto the patterned structure 250 on the side opposite to the first layer of cover material. Fig.13 , a cross-sectional view of a sheath 230 having features of the present invention is shown according to the present technology. As shown, in the present invention, the cover includes a first layer 261 and a second layer 262, and the patterned structure 250 is embedded between the cover layers 261 and 262. Therefore, 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).

[0089] Then, in step 1010, the patterned structure and the covering material are cut along the sheath, and in step 1011, the liner is laminated to the interior of the sheath. In one aspect, for step 1011, the liner material can be laminated to the interior of the sheath using mandrels of different sizes or materials for masking to prevent any unwanted covering material from forming when reheated. For example, in this aspect, after the patterned structure 250 and the covering material are cut, when the patterned structure 250 and the covering material are laminated to the inner liner layer, the lamination occurs on a mandrel with a smaller diameter than that used in step 1009. In step 1011, the purpose of the smaller diameter mandrel is to allow the slit sheath to form the desired shape. Due to this smaller mandrel, during this lamination step, the covering material may form or adhere to itself, thereby preventing the wrapped sheath from expanding when completed. To prevent this from happening, the size of the inner liner layer and the mandrel is selected to allow the inner liner layer to overlap, thereby preventing the covering layer from contacting itself when the sheath is wrapped. Optionally, a masking technique can be used to prevent such contact.

[0090] In any aspect of the method 1000, in step 1012, the sheath 230 is allowed to curl inwardly on itself so that a first portion of the sheath 230 extending along the slit 234 and a second portion of the sheath 230 extending along the slit 234 overlap to form a longitudinal fold. It should be understood that if the liner 240 is not cut (i.e., step 1009 is performed), then at step 1012, the portion of the liner 240 extending along the longitudinal length of the sheath is folded to overlap. In either case, after the sheath 230 is cut, the patterned structure is configured to apply a curling force to the sheath 230 so that the sheath 230 curls inwardly on itself. In step 1014, a sealing material (e.g., an elastomer) is applied to the covering 260 to form a seal 270, which is configured to seal the slit 234 to prevent fluid (e.g., blood) from leaking from the lumen 232 through the slit 234 when the sheath 230 is inserted into the patient's vascular system. Fig.11 , which shows a cross-sectional view of the sheath body 230 produced after steps 1012 and 1014. In one aspect, step 1012 includes shrink-wrapping a sealing material over the cover 260. In step 1016, the proximal end 202 of the sheath body 230 is attached to a sheath hub (e.g., hub 110) to form an expandable sheath assembly, such as sheath assembly 200.

[0091] In another aspect, the method 1000 may further include an additional step prior to applying the sealing material (step 1014) and attaching the hub (step 1016) wherein the sheath 230 is again laminated onto the tapered mandrel and again heated to form the proximal end.

[0092] In this step, the cover material is attached to the sheath body. It can be attached at the proximal and distal ends of the sheath body or along the entire length of the sheath. It can be connected to the sheath body in a curled form or by expanding the sheath on a larger mandrel. Optionally, an additional step can be performed on a larger diameter mandrel to heat the sheath body 230 to allow the cover to encapsulate the patterned structure 250.

[0093] The curled design of the sheath body 230, 330, 430 and the manufacturing method 1000 thereof provide many advantages over existing sheath assemblies and reduce or eliminate many disadvantages in the above-mentioned existing sheath assemblies. For example, the seal 270 seals the slit 234 along the sheath body 230 and is configured to prevent bleeding / thrombosis during the long-term use of the sheath assembly 200 in the patient's body. In addition, the sheath body 230 uses the patterned structure 250 to increase the anti-kink amount relative to the existing sheath assembly design and provide excellent column strength. The increased torsion resistance contributes to safer surgery. The folding arrangement and use of the patterned structure 250 enable the sheath body 230 to radially expand to an expanded state and also automatically rebound to a state substantially similar to the original unexpanded state without the need for a user-operated brake mechanism. In addition, the folding arrangement enables the sheath body 230 to have a reduced diameter relative to a sheath body of a fixed diameter. In addition, the design of the proposed sheath body 230 is easy to manufacture.

[0094] In one aspect of the present technology, an expandable sheath is provided, comprising an elongated sheath body having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end. The elongated sheath body comprises a first layer, a second layer, and a third layer. The first layer is a lining defining the lumen. The second layer is disposed on the first layer, and the second layer is a patterned structure. The third layer is disposed on the second layer. The elongated sheath body comprises a slit passing through the second layer and the third layer, wherein the slit extends along at least a portion of the elongated sheath body. The first portion of the elongated sheath body overlaps with the second portion of the elongated sheath body along the slit to form a fold.

[0095] In some aspects, the elongated sheath is configured to radially expand from an unexpanded state to an expanded state to allow a portion of the medical device to pass through the lumen, and when the elongated sheath is in the unexpanded state, the cross-sectional area of ​​the portion of the medical device is greater than the cross-sectional area of ​​the lumen.

[0096] In some aspects, the medical device is an intracardiac heart pump.

[0097] In some aspects, when the elongated sheath body is radially expanded, the overlap between the first portion of the elongated sheath body and the second portion of the elongated sheath body is reduced such that the cross-sectional area of ​​the lumen is increased.

[0098] In some aspects, the elongate sheath is configured to relax when a portion of the medical device is removed from the lumen such that the cross-sectional area of ​​the lumen is reduced and the elongate sheath substantially returns to the cross-sectional area of ​​the unexpanded state.

[0099] In some aspects, the first layer is made of polytetrafluoroethylene (PTFE) or an elastomer.

[0100] In some aspects, the first layer includes a lubricious coating on an interior surface of the first layer.

[0101] In some aspects, the first layer includes a hydrophilic coating on an interior surface of the first layer.

[0102] In some aspects, the slit of the elongated sheath further extends through the first layer.

[0103] In some aspects, the first layer includes a folded portion extending along at least a portion of the elongated sheath.

[0104] In some aspects, in a cross-section of the first layer, the first layer is continuous and does not include any breaks around its circumference.

[0105] In some aspects, the second layer is made of metal.

[0106] In some aspects, the metal is stainless steel or nitinol.

[0107] In some aspects, the patterned structure is a coil.

[0108] In some aspects, the patterned structure is embedded within the third layer.

[0109] In some aspects, the third layer is made of thermoplastic.

[0110] In some aspects, the third layer is made of thermoplastic polyurethane (TPU) or polyether block amide.

[0111] In some aspects, the elongated sheath is tubular.

[0112] In some aspects, the elongated sheath further includes a fourth layer disposed on the third layer, the fourth layer configured to seal the folds in the elongated sheath.

[0113] In some aspects, the fourth layer is made of an elastomer.

[0114] In some aspects, the fourth layer is made of TPU or polysiloxane.

[0115] In some aspects, the expandable sheath further comprises a hub, wherein the proximal end of the elongated sheath body is coupled to the hub.

[0116] Based on the above and with reference to the various drawings, those 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. Although several aspects of the present disclosure are shown in the drawings, it is not intended that the present disclosure is limited thereto, as the scope of the present disclosure should be as broad as possible and the specification should be interpreted in the same manner. Therefore, the above description should not be interpreted as limiting, but only as an example of specific aspects. Those skilled in the art will appreciate other modifications within the scope and spirit of the appended claims.

Claims

1. An expandable sheath comprising: an elongated sheath having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end, The elongated sheath comprises: a first layer, wherein the first layer is a lining defining the lumen; a second layer disposed on the first layer, wherein the second layer is a patterned structure; a third layer disposed on the second layer; wherein the elongated sheath comprises a slit through the second layer and the third layer, wherein the slit extends along at least a portion of the elongated sheath, and The first portion of the elongated sheath overlaps with the second portion of the elongated sheath along the slit to form a fold.

2. An expandable sheath according to claim 1, wherein the slender sheath body is configured to radially expand from an unexpanded state to an expanded state to allow a portion of the medical device to pass through the lumen, and when the slender sheath body is in the unexpanded state, the cross-sectional area of ​​the portion of the medical device is larger than the cross-sectional area of ​​the lumen.

3. An expandable sheath according to claim 2, wherein the medical device is an intracardiac heart pump.

4. The expandable sheath according to claim 2 or 3, wherein when the slender sheath body is radially expanded, the overlap between the first portion of the slender sheath body and the second portion of the slender sheath body is reduced, thereby increasing the cross-sectional area of ​​the lumen.

5. An expandable sheath according to any one of claims 2 to 4, wherein the slender sheath body is configured to relax when a portion of the medical device is removed from the lumen, so that the cross-sectional area of ​​the lumen is reduced and the slender sheath body substantially returns to the cross-sectional area in the unexpanded state.

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

7. The expandable sheath of any one of claims 1 to 6, wherein the first layer comprises a lubricious coating on an inner surface of the first layer.

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

9. The expandable sheath according to any one of claims 1 to 8, wherein the slit of the elongated sheath further penetrates the first layer.

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

11. The expandable sheath of claim 10, wherein in a cross-section of the first layer, the first layer is continuous and does not include any breaks in a circumference of 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 of claim 12, wherein the metal is stainless steel or nitinol.

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

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

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

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 of any one of claims 1 to 16, wherein the elongated sheath body is tubular.

19. The expandable sheath of any one of claims 1 to 18, wherein the elongated sheath body further comprises a fourth layer disposed on the third layer, the fourth layer being configured to seal the fold in the elongated sheath body.

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

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

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

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