Expandable sheath for introducing intravascular delivery devices into the body

Abstract

The present invention relates to an expandable sheath that can be used in conjunction with a catheter assembly to introduce an artificial device, such as a heart valve, into a patient. [Solution] In this embodiment, trauma to blood vessels can be minimized by allowing a portion of the introducer sheath to be temporarily expanded to adapt to the delivery device, and then returning to its original diameter as the prosthesis passes through. Some embodiments may include various configurations of the sheath comprising an elongated tube having the disclosed composition which may form an outer jacket or strain relief jacket or be used as an outer layer of the sheath. This expandable sheath embodiment can avoid the need for multiple insertions for blood vessel expansion, reduce the pressing force required for the passage of the medical device, and thus offer advantages over introducer sheaths of the prior art.

Description

[Technical Field]

[0001] Cross-references to related applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 059,772, filed on 31 July 2020, the contents of which are incorporated herein by reference in their entirety.

[0002] This application relates to an embodiment of a sheath for use in conjunction with catheter-based technologies for repairing and / or replacing heart valves, and for delivering prosthetic devices such as artificial valves to the heart via a patient's vascular system. [Background technology]

[0003] Intravascular delivery catheter assemblies are used to implant prosthetic devices, such as artificial valves, in locations inside the body that are not easily accessible by surgical procedures, or where minimally invasive access is desirable. For example, aortic, mitral, tricuspid, and / or pulmonary valve prostheses can be delivered to the treatment site using minimally invasive surgical techniques.

[0004] An introducer sheath can be used to safely introduce a delivery device into the patient's vascular system (e.g., the femoral artery). An introducer sheath generally comprises an elongated sleeve inserted into the vascular system and a housing containing one or more sealing valves that allow the delivery device to be positioned in fluid communication with the vascular system with minimal blood loss. Conventional introducer sheaths typically require a tubular loader to be inserted through a seal within the housing to provide an unobstructed pathway through the housing for valves mounted on a balloon catheter. Conventional loaders extend from the proximal end of the introducer sheath and therefore reduce the available working length of the delivery device that can be inserted into the body through the sheath.

[0005] Before introducing a delivery system, conventional methods of accessing blood vessels such as the femoral artery involve dilating the blood vessel using a plurality of dilators or sheaths with progressively increasing diameters. This repeated insertion and blood vessel dilation can increase the amount of time required for the procedure, as well as the risk of damage to the blood vessel.

[0006] An intravascular sheath that expands radially is disclosed. Such a sheath tends to have a complex mechanism, such as a latch mechanism, that maintains the shaft or sheath in an expanded configuration when a device having a diameter larger than the original diameter of the sheath is introduced.

[0007] However, the delivery and / or removal of prostheses and other materials to or from the patient still poses a significant risk to the patient. Furthermore, accessing the blood vessel remains problematic due to the relatively large outer shape of the delivery system, which can cause longitudinal and radial tears in the blood vessel during insertion. The delivery system can also dislodge calcified plaque within the blood vessel, resulting in an additional risk of thrombus caused by the dislodged plaque.

[0008] Therefore, there remains a need in the art for an improved introducer sheath for intravascular systems used to implant valves and other prostheses. SUMMARY OF THE INVENTION

[0009] The expandable sheaths disclosed herein can minimize trauma to blood vessels by allowing temporary expansion of a portion of the introducer sheath to adapt to a delivery system, and then returning to its original diameter as the delivery system passes through. Some embodiments may include a sheath having a smaller external profile than the introducer sheath of the prior art. Furthermore, as described in certain embodiments, the disclosed sheaths can reduce the length of the procedure and reduce the risk of longitudinal or radial vascular laceration or plaque ablation because only one sheath is required, rather than several different sizes of sheaths. In even further embodiments, the expandable sheath may require only a single vascular insertion, in contrast to requiring multiple insertions for vascular dilation.

[0010] In one embodiment, disclosed herein is a sheath for delivering a medical device, the sheath having a proximal end and a distal end, and comprising an elongated tube having an inner and outer surface, positioned at least at the proximal end of the sheath, extending along at least a portion of the length of the sheath, the elongated tube comprising a first polymer layer, the first polymer layer comprising a first composite composition comprising a first polymer comprising more than 0% to 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of an inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of a solid lubricant filler based on the total weight of the first composite composition, the elongated tube having an initial diameter d0 in a non-expanded position and an expanded diameter d in an expanded position when the medical device passes through. e Configured to expand reversibly, the sheath exhibits at least a 10% reduction in insertion force compared to a substantially identical reference sheath without the first polymer layer.

[0011] In one embodiment, the first polymer may have substantially the same durometer along the entire length of the elongated tube. Furthermore, in another embodiment, the durometer of the first polymer at the proximal end of the elongated tube may differ from the durometer of the first polymer at the distal end of the elongated tube.

[0012] In one embodiment, the elongated tube comprises two or more polymer layers. In such exemplary embodiments, the elongated tube comprises at least a second polymer layer comprising a second composite composition comprising a second polymer containing more than 0% to 100% by weight of a polyether block amide, polyurethane, or a composition thereof. In certain exemplary embodiments, the second composite composition may further contain up to 20% of tackiness-reducing additives based on the total weight of the second composite composition.

[0013] In further embodiments, the second polymer layer may include PEBAX®. On the other hand, in other embodiments, the second polymer layer may include polyurethane.

[0014] In some embodiments, the sheaths disclosed herein may exhibit at least a 20% reduction in insertion force compared to a substantially identical reference sheath without the first polymer layer.

[0015] In a further embodiment, the disclosed sheath for introducing an orthotic device comprises an inner layer and an outer layer. In one embodiment, the sheath disclosed herein comprises an expandable tubular inner liner extending along the length of the sheath and having at least one folded portion, wherein the expandable inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of at least one folded portion, and the outer surface extending circumferentially and forming the outer surface of at least one folded portion; and a first outer tubular layer extending at least partially along the length of the sheath and having an inner surface and an outer surface, wherein the inner surface of the first outer tubular layer further extends at least partially around the outer surface of the inner liner such that at least a portion of the inner surface of the first outer tubular layer is positioned adjacent to the outer surface of at least one folded portion of the inner liner, and an elongated tube is positioned such that at least a portion of the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer.

[0016] In further embodiments, the sheath disclosed herein is an expandable tubular inner liner having a proximal end and a distal end and comprising at least one folded portion, wherein the expandable tubular inner liner has an inner surface and an outer surface, the inner surface of the expandable tubular inner liner defining a lumen and forming the inner surface of at least one folded portion, and the outer surface extending circumferentially and forming the outer surface of at least one folded portion, and a first outer tubular layer having an inner surface and an outer surface, wherein at least a portion of the inner surface of the first outer tubular layer is positioned adjacent to the outer surface of at least one folded portion of the inner liner, the inner surface of the first outer tubular layer is at least a portion of the outer surface of the inner liner The sheath comprises a first outer tubular layer extending around the sheath, and an elongated tube forming a second outer layer having an inner and outer surface, wherein the elongated tube is located at least at the proximal end of the sheath and extends along at least a portion of the length of the sheath such that the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer, the elongated tube comprises a first polymer layer, the first polymer layer comprises a first composite composition comprising a polymer including more than 0% to less than 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of solid lubricant filler based on the total weight of the first composite composition.

[0017] Also disclosed herein is an embodiment describing a sheath for delivering a medical device, the sheath comprising an expandable tubular inner liner having a proximal end and a distal end and comprising at least one folded portion, wherein the expandable tubular inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of at least one folded portion, the outer surface extending circumferentially and forming the outer surface of at least one folded portion, and the outer surface of the inner liner is selectively etched, and a first outer tubular layer having an inner surface and an outer surface, wherein at least a portion of the inner surface of the outer layer is positioned adjacent to at least a portion of the outer surface of at least one folded portion of the inner liner The device comprises a first outer tubular layer extending at least partially around the outer surface of the inner liner, and an elongated tube forming a second outer layer having an inner and outer surface, wherein the elongated tube is located at least at the proximal end of the sheath and extends along at least a portion of the length of the sheath such that the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer, the elongated tube comprising a first polymer layer, the first polymer layer comprising a first composite composition comprising a first polymer including more than 0% to less than 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of solid lubricant filler based on the total weight of the first composite composition.

[0018] Furthermore, disclosed herein, in addition to the elongated tube described in any of the embodiments described above, further comprises a variable diameter inner liner comprising a sheet having a first edge and a second edge, and defined by an inner and outer surface, wherein the sheet is wound in a helical configuration such that at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, the first edge of the sheet is slidable along at least a portion of the inner surface of the sheet, and the second edge is slidable along at least a portion of the outer surface of the sheet, the inner surface of the sheet defines a cylindrical lumen having a longitudinal axis, and the variable diameter inner liner, while a radially outward force is applied due to the passage of a medical device through the lumen of the inner liner, slides the first edge of the sheet along at least a portion of the inner surface and slides the second edge of the sheet along at least a portion of the outer surface, thereby achieving a predetermined stationary diameter d r This embodiment is configured to expand reversibly from an initial diameter to an expanded diameter d1, and the elongated tube is positioned such that the inner surface of the elongated tube covers at least a portion of the outer surface of the inner liner.

[0019] Also disclosed herein is a sheath for delivering a medical device, the sheath comprising a variable diameter inner liner having a proximal end and a distal end, a first edge and a second edge, and defined by an inner surface and an outer surface, wherein the sheet is wound in a helical configuration such that at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, the first edge of the sheet is slidable along at least a portion of the inner surface of the sheet, the second edge is slidable along at least a portion of the outer surface of the sheet, the inner surface of the sheet defines a cylindrical lumen having a longitudinal axis, and the variable diameter inner liner, while a radially outward force is applied due to the passage of a medical device through the lumen of the inner liner, slides the first edge of the sheet along at least a portion of the inner surface and slides the second edge of the sheet along at least a portion of the outer surface, thereby achieving a predetermined stationary diameter d rThe device comprises a variable-diameter inner liner configured to reversibly expand from a diameter d1 to an expanded diameter d1, and an elongated tube forming an outer layer having an inner and outer surface, wherein the elongated tube is located at least at the proximal end of the sheath and extends along at least a portion of the length of the sheath such that the inner surface of the elongated tube covers at least a portion of the outer surface of the inner liner, the elongated tube comprising a first polymer layer, the first polymer layer comprising a first composite composition comprising a first polymer comprising more than 0% to less than 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of solid lubricant filler based on the total weight of the first composite composition.

[0020] Also disclosed herein is an expandable tubular layer comprising: an inner tubular layer having a longitudinal slit and partially defining an inner lumen; a first outer tubular layer enclosing the inner layer, the first outer tubular layer having a longitudinally extending folded flap that covers a portion of the outer surface of the outer layer when the sheath is in an unexpanded state; and an elongated tube forming a second outer layer having an inner and outer surface, the elongated tube being located at least at the proximal end of the sheath and extending along at least a portion of the length of the sheath such that the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer. The sheath, an elongated tube, comprises a first polymer layer, the first polymer layer comprising a first composite composition comprising a first polymer comprising more than 0% to less than 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than 65% by weight of inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of solid lubricating filler based on the total weight of the first composite composition, wherein outward-directed radial forces from the prosthesis moving through the inner lumen expand the longitudinal slit and unfold the folded flap, allowing the sheath to expand.

[0021] Further disclosed herein is a sheath for delivering a medical device, comprising a continuous inner layer defining a lumen through which the inner layer comprises a first fold and a second fold and an overlapping folded portion extending circumferentially between the first fold and the second fold, the folded portion comprising a radial overlap of at least two thicknesses of the inner layer; a discontinuous first outer tubular layer extending circumferentially around at least a portion of the inner layer, the discontinuous first outer tubular layer having an overlapping portion and a lower portion, with at least a portion of the folded portion of the inner layer positioned between the overlapping portion and the lower portion; and an elongated tube forming a second outer layer having an inner surface and an outer surface, the elongated tube positioned at least at the proximal end of the sheath, the inner surface of the elongated tube covering at least a portion of the outer surface of the first outer tubular layer. A sheath comprising an elongated tube extending along at least a portion of its length, the elongated tube comprising a first polymer layer, the first polymer layer comprising a first composite composition comprising a first polymer comprising more than 0% to less than 100% by weight of a polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of an inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of a solid lubricating filler based on the total weight of the first composite composition, wherein at least a portion of the sheath is configured to locally expand from a non-expandable configuration having a first diameter to an expanded configuration having a second diameter having a second diameter greater than the first diameter due to an outwardly directed radial force exerted on the inner layer by a medical device, and then locally contract back to at least partially the non-expandable configuration as the prosthesis passes through the lumen.

[0022] Also disclosed herein is a sheath for delivering a medical device, comprising a continuous inner layer defining a lumen through which the inner layer comprises a first fold and a second fold and an overlapping folded portion extending circumferentially between the first fold and the second fold, wherein the folded portion includes a radial overlap of at least two thicknesses of the inner layer; a discontinuous first outer tubular layer extending circumferentially around at least a portion of the inner layer, wherein the first outer tubular layer has an overlapping portion and a lower portion, and at least a portion of the folded portion of the inner layer is positioned between the overlapping portion and the lower portion; a coiled wire along the length of the sheath, which provides uniform bending of the sheath and prevents twisting; and an elongated tube forming a second outer layer having an inner surface and an outer surface, wherein the elongated tube is positioned at least at the proximal end of the sheath, and the inner surface of the elongated tube is the first outer A sheath comprising an elongated tube extending along at least a portion of the length of the sheath so as to cover at least a portion of the outer surface of a lateral tubular layer, wherein the elongated tube comprises a first polymer layer, the first polymer layer comprising a first composite composition comprising a first polymer comprising more than 0% to less than 100% by weight of a polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of an inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of a solid lubricating filler based on the total weight of the first composite composition, wherein at least a portion of the sheath is configured to locally expand from a non-expandable configuration having a first diameter to an expanded configuration having a second diameter having a larger diameter than the first diameter due to an outwardly directed radial force exerted on the inner layer by a medical device, and then locally contract back to at least partially the non-expandable configuration as the prosthesis passes through the lumen.

[0023] Also disclosed herein is a method for producing a sheath having a proximal end and a distal end, a) extruding a tubular body to form an elongated tube comprising a first polymer layer, wherein the first polymer layer comprises a first composite composition, which, based on the total weight of the first composite composition, comprises a polymer comprising more than 0% to less than 100% of polyether block amide, polyurethane, or a combination thereof, less than about 65% of an inorganic filler based on the total weight of the first composite composition, and up to about 20% of a solid lubricant filler based on the total weight of the first composite composition, and b) arranging an elongated tube on a sheath such that the elongated tube forms the outer layer of the sheath, wherein the elongated tube is positioned at least at the proximal end of the sheath and extends along at least a portion of the length of the sheath, and the elongated tube changes from an initial diameter d0 in the non-expanded position to an expanded diameter d in the expanded position when a medical device passes through. e A method comprising positioning a sheath configured to expand reversibly to a certain extent, wherein the formed sheath exhibits at least a 10% reduction in insertion force compared to a substantially identical reference sheath without a first polymer layer.

[0024] Also disclosed herein are: a) a continuous inner layer defining a lumen through which the inner layer comprises a first fold and a second fold and an overlapping folded portion extending circumferentially between the first fold and the second fold, wherein the folded portion includes a radial overlap of at least two thicknesses of the inner layer; b) a discontinuous first outer tubular layer extending at least partially around the inner layer, wherein the first outer tubular layer has an overlapping portion and a lower portion, wherein at least a portion of the folded portion of the inner layer is positioned between the overlapping portion and the lower portion; and c) the length of the sheath A method comprising providing a coiled wire along a sheath, which provides uniform bending of the sheath and prevents twisting, and further comprising arranging an elongated tube such that the inner surface of the elongated tube covers at least a portion of the outer surface of a first outer tubular layer, wherein at least a portion of the sheath is configured to locally expand from a non-expanded configuration having a first diameter to an expanded configuration having a second diameter having a larger diameter than the first, due to an outwardly directed radial force exerted on the inner layer by a medical device, and then locally contract back to at least a portion of the non-expanded configuration as the prosthesis passes through the lumen.

[0025] Further disclosed herein are a) a circumferentially continuous first elastic outer tubular layer defining an initial elastic lumen extending axially through it, wherein the initial elastic lumen is a circumferentially continuous first elastic outer tubular layer having an initial diameter, and b) an inner tubular layer extending through the first elastic lumen of the first elastic outer tubular layer, comprising at least three circumferentially spaced longitudinally extending thick-walled segments and at least three circumferentially spaced longitudinally extending thin-walled segments, wherein each thin-walled segment extends between two adjacent thick-walled segments to define an expanded lumen extending axially through the inner tubular layer, wherein the expanded lumen has an expanded diameter greater than the initial diameter of the initial elastic lumen. A method to provide a tubular layer, further comprising: c) an inner tubular layer having a radial thickness of three layers, each of which, in a compressed state, forms at least three circumferentially separated folds, and each of the circumferentially separated folds comprising a portion of two adjacent thick-walled segments and a thin-walled segment sandwiched between them; the inner tubular layer having expanded and separated thick-walled and thin-walled segments in a locally expanded state; and configured such that, after the passage of an implant through the expanded lumen, the inner tubular layer is pushed back into a compressed state by a first elastic outer tubular layer, at least partially; and arranging an elongated tube such that its inner surface covers at least a portion of the outer surface of the first elastic outer layer.

[0026] Also disclosed herein are: a) an expandable tubular inner liner extending along the length of a sheath and comprising at least one folded portion, wherein the expandable inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of at least one folded portion, and the outer surface extending circumferentially and forming the outer surface of at least one folded portion; and b) a first outer tubular layer extending at least partially along the length of a sheath and comprising an inner surface and an outer surface, wherein at least a portion of the inner surface of the first outer tubular layer is adjacent to the outer surface of at least one folded portion of the inner liner. A method comprising providing a first outer tubular layer such that the inner surface of the first outer tubular layer extends further around at least a portion of the outer surface of the inner liner, and arranging an elongated tube such that the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer, wherein at least a portion of the sheath is configured to locally expand from a non-expandable configuration having a first diameter to an expanded configuration having a second diameter having a larger diameter than the first, due to an outwardly directed radial force exerted on the inner layer by a medical device, and then locally contract back to at least a portion of the non-expandable configuration as the prosthesis passes through the lumen.

[0027] The aforementioned and other features and advantages of this disclosure will become more apparent from the following detailed description, which will proceed with reference to the attached drawings. [Additional note 1] A sheath for delivering a medical device, wherein the sheath has a proximal end and a distal end. The sheath comprises an elongated tube located at least at the proximal end of the sheath, extending along at least a portion of the length of the sheath, having an inner surface and an outer surface, forming an outer layer of the sheath, wherein the elongated tube comprises a first polymer layer, and the first polymer layer is a first composite composition. Based on the total weight of the first composite composition, a first polymer comprising more than 0% by weight and less than 100% by weight of polyether block amide, polyurethane, or a combination thereof, Based on the total weight of the first composite composition, less than 65% inorganic filler and The first composite composition comprises, based on the total weight of the first composite composition, up to approximately 20% solid lubricating filler, The aforementioned elongated tube changes from an initial diameter d0 in the non-expanded position to an expanded diameter d in the expanded position as the medical device passes through it. e It is configured to be reversibly expandable up to A sheath which exhibits at least a 10% reduction in insertion force compared to a substantially identical reference sheath without the first polymer layer, and the elongated tube is substantially torsion-resistant. [Additional note 2] The sheath according to Appendix 1, wherein the durometer of the first polymer at the proximal end of the elongated tube has a Shore D of about 20D to about 35D, unlike the durometer of the first polymer at the distal end of the elongated tube. [Additional note 3] The sheath according to Appendix 1 or 2, wherein the first polymer comprises a polyether block amide elastomer. [Additional note 4] The sheath according to Appendix 1 or 2, wherein the first polymer comprises polyurethane. [Additional note 5] The sheath according to any one of the appendices 1 to 4, wherein the inorganic filler comprises bismuth chloride oxide, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof, and is present in an amount of at least about 10% based on the total weight of the first composite composition. [Additional note 6] The sheath according to any one of the appendices 1 to 5, wherein the inorganic filler is present in an amount less than 50% of the total weight of the first composite composition. [Additional note 7] A sheath as described in any one of the appendices 1 to 6, wherein the solid lubricant includes a PTFE filler. [Additional note 8] The sheath according to any one of the appendices 1 to 7, wherein the first composite composition further comprises at least one tackiness-reducing compound present in an amount of about 1% to about 20% based on the total weight of the first composite composition. [Additional note 9] The sheath according to any one of the appendices 1 to 8, wherein the elongated tube comprises two or more polymer layers. [Additional Note 10] The sheath according to Appendix 9, wherein the elongated tube comprises at least a second polymer layer comprising a second composite composition comprising a second polymer containing more than 0% to 100% by weight of a polyether block amide, polyurethane, or a composition thereof, the second polymer having a Shore A durometer of about 20A to about 65A. [Additional Note 11] The sheath according to Appendix 10, wherein the second composite composition further comprises up to 20% of a tackiness-reducing additive based on the total weight of the second composite composition. [Additional Note 12] The sheath according to appendix 10 or 11, wherein the second polymer includes polyurethane. [Additional Note 13] The sheath according to any one of appendices 10 to 12, wherein the elongated tube has a predetermined thickness, and at least about 50% of the predetermined thickness comprises the first composite composition and / or the second composite composition. [Additional Note 14] The sheath according to any one of appendices 10 to 13, wherein one or more additional polymer layers are disposed between the first polymer layer and the second polymer layer. [Additional Note 15] The sheath according to appendix 14, wherein the one or more additional polymer layers comprise at least one intermediate reinforcing layer extending axially for at least a portion of the length of the elongated tube. [Additional Note 16] The sheath according to Appendix 15, wherein the at least one intermediate reinforcing layer comprises the first polymer, the second polymer, a polyolefin polymer, or a combination thereof. [Additional Note 17] The sheath according to appendix 15 or 16, wherein the at least one intermediate reinforcing layer comprises a material having a Shore D durometer of about 45D to about 76D. [Additional Note 18] The sheath according to any one of the appendices 15 to 17, wherein the at least one intermediate reinforcing layer is configured to be thermally bonded to the first polymer layer, the second polymer layer, or a combination thereof. [Additional Note 19] The sheath according to any one of the appendices 1 to 18, wherein the elongated tube exhibits a frictional force of less than about 10 N in a dry state against the surface of a substrate containing one or more of polytetrafluoroethylene or high-density polyethylene. [Additional Note 20] The sheath according to any one of the appendices 1 to 19, wherein the elongated tube exhibits a frictional force of less than approximately 7 N in a dry state against the surface of a substrate containing one or more of polytetrafluoroethylene or high-density polyethylene. [Additional Note 21] The sheath described in any one of the appendices 1 to 20, wherein the elongated tube exhibits a hoop-directional force of less than approximately 8 N at an extension of 10 mm. [Additional Note 22] The sheath described in any one of the appendices 1 to 21, wherein the elongated tube exhibits a fracture elongation in the range of approximately 600% to approximately 800%. [Additional Note 23] An expandable tubular inner liner extending along the length of the sheath and comprising at least one folded portion, wherein the expandable inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of the at least one folded portion, and the outer surface extending circumferentially and forming the outer surface of the at least one folded portion, A first outer tubular layer having an inner surface and an outer surface, extending at least partially along the length of the sheath, wherein the inner surface of the first outer tubular layer further extends at least partially around the outer surface of the inner liner, such that at least a portion of the inner surface of the first outer tubular layer is positioned adjacent to the outer surface of the at least one folded portion of the inner liner, The sheath according to any one of Appendix 1 to 22, wherein the elongated tube is positioned such that at least a portion of the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer, and the sheath exhibits an insertion force of less than about 55 N when a medical device is pushed through the sheath. [Additional note 24] The sheath according to Appendix 23, wherein the expandable tubular inner liner comprises polytetrafluoroethylene, or the first outer tubular layer comprises high-density polyethylene. [Additional note 25] A sheath for delivering a medical device, wherein the sheath has a proximal end and a distal end. An expandable tubular inner liner comprising at least one folded portion, wherein the expandable inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of the at least one folded portion, and the outer surface extending circumferentially and forming the outer surface of the at least one folded portion, A first outer tubular layer having an inner surface and an outer surface, wherein at least a portion of the inner surface of the first outer tubular layer is positioned adjacent to the outer surface of the at least one folded portion of the inner liner, and the inner surface of the first outer tubular layer extends at least partially around the outer surface of the inner liner, A slender tube having an inner surface and an outer surface, forming a second outer layer, wherein the slender tube is positioned at least at the proximal end of the sheath, and the inner surface of the slender tube extends along at least a portion of the length of the sheath such that it covers at least a portion of the outer surface of the first outer tubular layer, The elongated tube comprises a first polymer layer, and the first polymer layer is a first composite composition. Based on the total weight of the first composite composition, a polymer comprising more than 0% to less than 100% polyether block amide, polyurethane, or a combination thereof, Based on the total weight of the first composite composition, less than 65% inorganic filler and A sheath comprising the first composite composition, which comprises a solid lubricant filler up to approximately 20% based on the total weight of the first composite composition. [Additional note 26] A sheath for delivering a medical device, wherein the sheath has a proximal end and a distal end. An expandable tubular inner liner comprising at least one folded portion, wherein the expandable inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of the at least one folded portion, the outer surface extending circumferentially and forming the outer surface of the at least one folded portion, and the outer surface of the inner liner is selectively etched. A first outer tubular layer having an inner surface and an outer surface, wherein the inner surface of the outer layer extends at least partially around the outer surface of the inner liner such that at least a portion of the inner surface of the outer layer is positioned adjacent to at least a portion of the outer surface of the at least one folded portion of the inner liner, A slender tube having an inner surface and an outer surface, forming a second outer layer, wherein the slender tube is positioned at least at the proximal end of the sheath, and the inner surface of the slender tube extends along at least a portion of the length of the sheath such that it covers at least a portion of the outer surface of the first outer tubular layer, The elongated tube comprises a first polymer layer, and the first polymer layer is a first composite composition. Based on the total weight of the first composite composition, a polymer comprising more than 0% to less than 100% polyether block amide, polyurethane, or a combination thereof, Based on the total weight of the first composite composition, less than 65% inorganic filler and A sheath comprising the first composite composition, which comprises a solid lubricant filler up to approximately 20% based on the total weight of the first composite composition. [Additional note 27] A variable diameter inner liner comprising a sheet having a first edge and a second edge, and defined by an inner surface and an outer surface, wherein the sheet is wound in a helical configuration such that at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, the first edge of the sheet is slidable along at least a portion of the inner surface of the sheet, the second edge is slidable along at least a portion of the outer surface of the sheet, the inner surface of the sheet defines a cylindrical lumen having a longitudinal axis, and the variable diameter inner liner, while subjected to radially outward force due to the passage of a medical device through the lumen of the variable diameter inner liner, slides the first edge of the sheet along at least a portion of the inner surface and slides the second edge of the sheet along at least a portion of the outer surface, thereby achieving a predetermined stationary diameter d r It further comprises a variable-diameter inner liner configured to expand reversibly from to an expanded diameter d1, The sheath according to any one of the appendices 1 to 23, wherein the elongated tube is positioned such that the inner surface of the elongated tube covers at least a portion of the outer surface of the variable-diameter inner liner. [Additional note 28] The sheath according to Appendix 27, further comprising a braid positioned between the variable-diameter inner liner and the elongated tube. [Additional note 29] The sheath according to appendix 27 or 28, further comprising an additional outer layer that can be positioned between the variable-diameter inner liner and the elongated tube. [Additional note 30] The sheath according to any one of the appendices 27 to 29, wherein the sheet comprises high-density polyethylene, polypropylene, polyamide, fluoropolymer, copolymer thereof, or a blend thereof. [Additional note 31] The sheath according to any one of the appendices 27 to 30, wherein a certain amount of a first lubricant is disposed between at least a portion of the variable diameter inner liner and at least a portion of the inner surface of the elongated tube. [Additional note 32] The sheath according to any one of the appendices 27 to 31, wherein a certain amount of a second lubricant is disposed between at least a portion of the layered portion of the sheet and at least a portion of the sliding portion of the sheet. [Additional note 33] A sheath as described in any one of the appendices 28 to 32, wherein the braid comprises at least one filament, which includes stainless steel, nitinol, polymer material, or composite material. [Additional note 34] A sheath for delivering a medical device, wherein the sheath has a proximal end and a distal end. A variable diameter inner liner comprising a sheet having a first edge and a second edge, and defined by an inner surface and an outer surface, wherein the sheet is wound in a helical configuration such that at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, the first edge of the sheet is slidable along at least a portion of the inner surface of the sheet, the second edge is slidable along at least a portion of the outer surface of the sheet, the inner surface of the sheet defines a cylindrical lumen having a longitudinal axis, and the variable diameter inner liner, while subjected to radially outward force due to the passage of a medical device through the lumen of the variable diameter inner liner, slides the first edge of the sheet along at least a portion of the inner surface and slides the second edge of the sheet along at least a portion of the outer surface, thereby achieving a predetermined stationary diameter d r A variable-diameter inner liner configured to reversibly expand from to an expanded diameter d1, An elongated tube having an inner surface and an outer surface, forming an outer layer, wherein the elongated tube is positioned at least at the proximal end of the sheath, and the inner surface of the elongated tube extends along at least a portion of the length of the sheath such that it covers at least a portion of the outer surface of the variable diameter inner liner, The elongated tube comprises a first polymer layer, and the first polymer layer is a first composite composition. Based on the total weight of the first composite composition, a polymer comprising more than 0% to less than 100% polyether block amide, polyurethane, or a combination thereof, Based on the total weight of the first composite composition, less than 65% inorganic filler and A sheath comprising the first composite composition, which comprises a solid lubricant filler up to approximately 20% based on the total weight of the first composite composition. [Additional note 35] A method for manufacturing a sheath having a proximal end and a distal end, a) Extruding a tubular body to form an elongated tube having a first polymer layer, wherein the first polymer layer is a first composite composition, Based on the total weight of the first composite composition, a polymer comprising more than 0% to less than 100% polyether block amide, polyurethane, or a combination thereof, Based on the total weight of the first composite composition, less than 65% inorganic filler and Forming a first composite composition comprising a first composite composition containing up to approximately 20% solid lubricating filler, based on the total weight of the first composite composition, b) Arranging the elongated tube on the sheath such that the elongated tube forms the outer layer of the sheath, wherein the elongated tube is positioned at least at the proximal end of the sheath, extends along at least a portion of the length of the sheath, and the elongated tube changes from an initial diameter d0 in the non-expanded position to an expanded diameter d in the expanded position when a medical device passes through. e It is configured to extend reversibly to, including, A method wherein the formed sheath exhibits at least a 10% reduction in insertion force compared to a substantially identical reference sheath without the first polymer layer. [Additional note 36] The method according to Appendix 35, wherein the elongated tube comprises a second polymer layer comprising a second composite composition comprising a second polymer containing 0% to 100% by weight of a polyether block amide, polyurethane, or a composition thereof. [Additional note 37] The method according to Appendix 36, wherein the extrusion step includes co-extruding the first polymer layer and the second polymer layer. [Additional note 38] The method according to any one of the appendices 35 to 37, wherein one or more additional polymer layers are disposed between the first polymer layer and the second polymer layer. [Brief explanation of the drawing]

[0028] [Figure 1] This is an elevation view of the sheath according to this disclosure, along with an intravascular delivery device for implanting an artificial valve. [Figure 2A] This is a cross-sectional view of an exemplary sheath for introducing an orthotic device to a patient. [Figure 2B] This is a cross-sectional view of an exemplary sheath for introducing an orthotic device to a patient. [Figure 2C] This is a perspective view of one component of such a sheath. [Figure 2D] This is a cross-sectional view of an exemplary sheath for introducing an orthotic device to a patient. [Figure 3] Figure 2 is an elevation view of the sheath. [Figure 4A] Elevation views of two embodiments of the sheath according to this disclosure, having various outer diameters, are shown. [Figure 4B] Elevation views of two embodiments of the sheath according to this disclosure, having various outer diameters, are shown. [Figure 5] An elevation view of one embodiment of the sheath, extended at a first location to adapt to a delivery system, is shown. [Figure 6] An elevation view of the extended sheath is shown at a second location further below the sheath. [Figure 7] A cross-sectional view of another embodiment of the sheath, further comprising an outer cover or shell, is shown. [Figure 8] An elevation view of one embodiment of a sheath having an outer cover or shell is shown. [Figure 9] A partial elevation view of one embodiment of an intermediate tubular layer that may be used to construct a sheath according to this disclosure is shown. [Figure 10] A partial elevation view of another embodiment of an intermediate tubular layer having a variable rhombic design is shown. [Figure 11] A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with spring supports is shown. [Figure 12] A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with straight support columns is shown. [Figure 13] A partial elevation view of another embodiment of an intermediate tubular layer having a sawtooth design with spring supports is shown. [Figure 14] A partial elevation view of another embodiment of an intermediate tubular layer having a sawtooth design with straight supports is shown. [Figure 15]A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with straight support columns is shown. [Figure 16] A partial elevation view of another embodiment of an intermediate tubular layer having a spiral or spiral-shaped support is shown. [Figure 17] A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with non-linear supports is shown. [Figure 18] A partial elevation view of another embodiment of an intermediate tubular layer having an alternative rhombic design with non-linear supports is shown. [Figure 19] A partial elevation view of another embodiment of an intermediate tubular layer having yet another rhomboid design with non-linear supports is shown. [Figure 20] A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with supporting columns is shown. [Figure 21] A partial elevation view of another embodiment of the intermediate tubular layer, similar to that shown in Figure 20 but with an additional support structure, is shown. [Figure 22] A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with spiral supports is shown. [Figure 23] A partial elevation view of another embodiment of an intermediate tubular layer having a rhomboid design with adjacent support columns is shown. [Figure 24] A cross-sectional view of one embodiment of a sheath having a vertical notch is shown. [Figure 25] A cross-sectional view of one embodiment of a sheath having a longitudinal cut in the inner layer is shown. [Figure 26] One embodiment shows a perspective view of an exemplary sheath having multiple notches or cuts in the outer tubular layer. [Figure 27A] The diagram shows a cross-sectional view of one embodiment of a sheath, in which the outer tubular layer includes longitudinal cuts, and the inner layer is non-expandable and extends within the gap created by the cuts in the outer tubular layer. [Figure 27B] This shows cross-sectional views of various sheath configurations in a non-extensioned setup. [Figure 27C] This shows cross-sectional views of various sheath configurations in a non-extensioned setup. [Figure 27D]This shows cross-sectional views of various sheath configurations in a non-extensioned setup. [Figure 27E] This shows cross-sectional views of various sheath configurations in a non-extensioned setup. [Figure 28] Figure 27A shows a cross-sectional view of the sheath in the extended configuration. [Figure 29A] Cross-sectional views of various embodiments of a sheath having overlapping sections are shown. [Figure 29B] Cross-sectional views of various embodiments of a sheath having overlapping sections are shown. [Figure 29C] Cross-sectional views of various embodiments of a sheath having overlapping sections are shown. [Figure 29D] Cross-sectional views of various embodiments of a sheath having overlapping sections are shown. [Figure 30] A block diagram of one embodiment of the method for manufacturing a sheath according to this disclosure is shown. [Figure 31] A block diagram of another embodiment of the method for manufacturing a sheath according to this disclosure is shown. [Figure 32A] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32B] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32C] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32D] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32E] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32F] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32G] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 32H] Figures 30 and 31 illustrate cross-sectional or elevation views of various method steps of the method shown. [Figure 33] A plan view of one embodiment of a sheath having a partial slit or cut line is shown. [Figure 34] A plan view of another embodiment of a sheath having a partial slit or cut line is shown. [Figure 35] This is an elevation view of the expandable sheath and a typical housing according to the present disclosure. [Figure 36] Figure 35 is a magnified cross-section of the distal end of the sheath. [Figure 37] This is a cross-sectional view of the distal end of the sheath shown in Figure 35, obtained along line 37-37 in Figure 36. [Figure 38] This is a cross-sectional view of the proximal section of the sheath in Figure 35, obtained along line 38-38 in Figure 35. [Figure 39] This is a cross-sectional view of the sheath in Figure 35 in a stationary (non-extended) configuration obtained along line 39-39 in Figure 35. [Figure 40] This is a cross-sectional view of the sheath in the extended configuration shown in Figure 39. [Figure 41] An elevation view of an expandable sheath with an elastic outer cover, according to another embodiment, is shown. [Figure 42] A cross-sectional view of the sheath shown in Figure 41, obtained along line 42-42 in Figure 41, is shown. [Figure 43] A cross-sectional view of the sheath shown in Figure 42 in the extended configuration is illustrated. [Figure 44] A cross-sectional view of another embodiment of the expandable sheath is shown. [Figure 45] Figure 44 shows the expanded configuration of the sheath. [Figure 46] A cross-sectional view of another embodiment of the expandable sheath is shown. [Figure 47] Figure 46 shows the expanded configuration of the sheath. [Figure 48] A cross-sectional view of another embodiment of the expandable sheath according to this disclosure is shown. [Figure 49] A cross-sectional view of another embodiment of the expandable sheath is shown. [Figure 50] This is an illustrative cross-sectional view of a sheath in a non-extended configuration. [Figure 51]This is a cross-sectional view of the sheath in the extended configuration shown in Figure 50. [Figure 52] Figure 50 is a cross-sectional view of the sheath, including the outer jacket. [Figure 53] This is a cross-sectional view of the sheath in Figure 35 in a stationary (non-expandable) configuration including the outer jacket, obtained along lines 39-39 in Figure 35. [Figure 54] This is a cross-sectional view of the sheath in Figure 53 in a stationary (non-extended) configuration obtained along line 39-39 in Figure 35. [Figure 55] This is a cross-sectional view of the sheath in the extended configuration shown in Figure 54. [Figure 56] Figure 54 is a cross-sectional view of the sheath in a stationary (non-expanding) configuration, with a lubricant included between the outer layer and the outer jacket. [Figure 57] This is a cross-sectional view of the sheath in Figure 54 in a stationary (non-expandable) configuration, including the lubricant and bonding strip. [Figure 58] Figure 57 is a perspective view of the bottom of the sheath. [Figure 59] Figure 57 is a perspective view of the bottom of the sheath. [Figure 60A] Figure 54 is a top perspective view of the sheath. [Figure 60B] This is a cross-sectional view of an exemplary sheath in one embodiment. [Figure 61A] This is a cross-sectional view of a sheath for introducing a medical device to a patient. [Figure 61B] This is a cross-sectional view of a sheath for introducing a medical device to a patient. [Figure 61C] This is a perspective view of one of the components of an exemplary sheath. [Figure 62A] A cross-sectional view of one embodiment of an exemplary inner liner is shown. Figure 62A depicts a non-extended configuration, while Figure 62B depicts an extended configuration. [Figure 62B] A cross-sectional view of one embodiment of an exemplary inner liner is shown. Figure 62A depicts a non-extended configuration, while Figure 62B depicts an extended configuration. [Figure 63A] Cross-sectional views of various exemplary sheath configurations are shown. [Figure 63B] Cross-sectional views of various exemplary sheath configurations are shown. [Figure 63C] Cross-sectional views of various exemplary sheath configurations are shown. [Figure 63D] Cross-sectional views of various exemplary sheath configurations are shown. [Figure 63E] Cross-sectional views of various exemplary sheath configurations are shown. [Figure 63F] Perspective views of various exemplary sheath configurations are shown. [Figure 63G] Perspective views of various exemplary sheath configurations are shown. [Figure 63H] Cross-sectional views of various exemplary sheath configurations are shown. [Figure 63I] Perspective views of various exemplary sheath configurations are shown. [Figure 64A] An exemplary cross-sectional view of the distal end of a sheath shows a lubricant positioned between the sliding portion and the layered portion of the sheet, and an exemplary cross-sectional view of a sheath having braids not embedded in the elastomer polymer layer. [Figure 64B] This is a cross-sectional view of the distal end of an exemplary sheath, showing that it has a lubricant positioned between the sliding portion and the layered portion of the sheet, and a lubricant positioned between the inner liner and the outer layer, and the braid is not embedded in the elastomer polymer layer. [Figure 64C] An exemplary cross-sectional view of the distal end of a sheath, showing a lubricant positioned between the inner liner and the outer layer, and illustrating an exemplary sheath where the braid is not embedded in the elastomer polymer layer, with and without the lubricant. [Figure 64D] The diagram shows a cross-sectional view of the distal end of an exemplary sheath, which has a lubricant positioned between the sliding portion and the layered portion of the sheet, and a lubricant positioned between the inner liner and the outer layer, and in which the braid is at least partially embedded in the elastomer polymer layer. [Figure 65A] The diagram shows a cross-sectional view of the proximal section of a sheath, illustrating an exemplary sheath having a lubricant positioned between the sliding portion and the layered portion of the sheet, and a braid not embedded in the elastomer polymer layer. [Figure 65B] This is a cross-sectional view of the proximal section of a sheath, showing an exemplary sheath having a lubricant positioned between the sliding portion and the layered portion of the sheet, and a lubricant positioned between the inner liner and the outer layer, and in which the braid is not embedded in the elastomer polymer layer. [Figure 65C] This is a cross-sectional view of the proximal section of a sheath, showing an exemplary sheath with a lubricant placed between the inner liner and the outer layer, and with and without the lubricant, where the braid is not embedded in the elastomer polymer layer. [Figure 65D] The diagram shows a cross-sectional view of the proximal section of a sheath, which has a lubricant positioned between the sliding portion and the overlapping portion of the sheet, and a lubricant positioned between the inner liner and the outer layer, and the braid is at least partially embedded in the elastomer polymer layer. [Figure 66] This is a cross-sectional view of the sheath in a stationary (non-expanded) configuration obtained along the distal end. [Figure 67] Figure 66 shows a cross-sectional view of the sheath in the extended configuration. [Figure 68] A block diagram of one embodiment of the method for manufacturing a sheath according to this disclosure is shown. [Figure 69] A block diagram of another embodiment of the method for manufacturing a sheath according to this disclosure is shown. [Figure 70A] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70B] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70C] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70D] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70E] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70F]Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70G] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70H] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70I] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 70J] Figures 68 and 69 illustrate cross-sectional or side views of various method steps of the method shown. [Figure 71] This is a cross-sectional view of an exemplary sheath in one embodiment. [Figure 72] This is a cross-sectional view of an exemplary sheath in one embodiment. [Figure 73] This is an exemplary elevation view of a long, slender pipe in a different embodiment. [Figure 74] This is a cross-sectional view of an exemplary elongated tube obtained along the cross-sectional line AA in Figure 73. [Figure 75] Figure 73 shows an exemplary cross-sectional view of an elongated tube in a stationary (non-expanded) configuration obtained along section line BB. [Figure 76] This is a partial cross-sectional view of an exemplary elongated tube in one embodiment. [Figure 77] Figure 73 shows another exemplary cross-sectional view of an elongated tube in a stationary (non-expandable) configuration including a single reinforcing member, obtained along the cross-sectional line BB. [Modes for carrying out the invention]

[0029] This disclosure can be more readily understood by referring to the following detailed description, examples, drawings, and claims, as well as their prior and hereafter described. However, before the articles, systems, and / or methods are disclosed and described, it should be understood that, unless otherwise specified, this disclosure is not limited to specific or exemplary embodiments of the disclosed articles, systems, and / or methods, and is therefore naturally subject to change. It should also be understood that the terms used herein are for the purpose of describing only specific embodiments and are not intended to be limiting.

[0030] The following description of the Disclosure is provided as a feasible teaching of the Disclosure in its best known form. For this purpose, a person skilled in the art will recognize and understand that many modifications can be made to the various forms of the Disclosure described herein, while still obtaining the beneficial results of the Disclosure. It will also be apparent that some of the desired benefits of the Disclosure can be obtained by selecting some of the features of the Disclosure without utilizing other features. Accordingly, a person skilled in the art will recognize that many modifications and adaptations to the Disclosure are possible, and may even be desirable in certain circumstances, and are part of the Disclosure. Accordingly, the following description is again provided as an example, and not as a limitation, of the principles of the Disclosure.

[0031] definition As used in this application and claims, the singular forms "a," "an," and "the" include the plural form unless the context explicitly indicates otherwise. Therefore, for example, unless the context explicitly indicates otherwise, a reference to "polymer" includes embodiments having two or more such polymers.

[0032] For clarity, it is understood that certain features of the Disclosure described in the context of a separate aspect may be provided in combination in a single aspect. Conversely, for brevity, various features of the Disclosure described in the context of a single aspect may also be provided separately or in any preferred combination.

[0033] As used herein, the terms “optional” or “optional” mean that the events or circumstances described below may or may not occur, and that the descriptions include both instances in which such events or circumstances occur and instances in which they do not.

[0034] Furthermore, it should be understood that the terms used herein are for the purpose of describing only specific embodiments and are not intended to be limiting. As used herein and in the claims, the term “comprising” may include “consisting of” and “essentially consisting of.” In addition, the term “includes” means “comprises.”

[0035] The terms "for example" and "etc.," as well as their grammatical equivalents, are understood to be followed by the phrase "but not limited to," unless explicitly stated otherwise.

[0036] References in this specification and the concluding claims to weight portions of a particular element or component in a composition or article indicate a weight relationship between the element or component and any other element or component in the composition or article, in which the weight portion is represented. Thus, in a composition or selected portion of a composition, comprising two weight portions of component X and five weight portions of component Y, X and Y exist in a weight ratio of 2:5, and such a ratio exists whether or not additional components are included in the composition.

[0037] Although the numerical ranges and parameters describing the broad scope of this disclosure are approximations, the numerical values ​​described in the specific examples are reported as accurately as possible. However, any numerical value inherently contains certain errors that inevitably arise from the standard deviation found in each test measurement. Furthermore, when numerical ranges of varying ranges are described herein, it is intended that any combination of these values, including the listed values, may be used. Furthermore, ranges may be expressed herein as "about" one particular value and / or "about" another particular value. When such ranges are expressed, another aspect includes "about" one particular value and / or the other particular value.

[0038] Similarly, when a value is expressed as an approximation, the use of the antecedent "approximately" indicates that a particular value takes on a different form. It will be further understood that each endpoint of a range is significant both in relation to the other endpoint and independently of the other endpoint. Unless otherwise stated, the term "approximately" means within 5% (e.g., within 2% or 1%) of the particular value modified by the term "approximately".

[0039] Throughout this disclosure, various aspects of the disclosure may be presented in scope form. It should be understood that scope form descriptions are for convenience and brevity only and should not be interpreted as inflexible limitations on the scope of the disclosure. Therefore, scope descriptions should be considered to specifically disclose all possible sub-ranges and individual numbers within that range. For example, a scope description such as 1–6 should be considered to specifically disclose sub-ranges such as 1–3, 1–4, 1–5, 2–4, 2–6, 3–6, and individual numbers within that range, such as 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any whole and partial increments between them. This applies regardless of the width of the range.

[0040] As used herein, the term “composition” is intended to encompass any product containing the specified components in specified amounts, as well as any product resulting directly or indirectly from any combination of the specified components in specified amounts.

[0041] The weight percentage of a component is based on the total weight of the formulation or composition containing that component, unless otherwise specifically stated.

[0042] As used herein, the term “substantially” means that the events or circumstances described later occur completely, or that the events or circumstances described later occur generally, typically, or approximately.

[0043] As used herein, the term “substantially” when used in relation to a composition means at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or about 100% of the specified features or components, based on the total weight of the composition.

[0044] As used herein, the term “substantially” in the context of “substantially not containing” means a composition having less than about 1% by weight of the described material, based on the total weight of the composition, for example, less than about 0.5% by weight, less than about 0.1% by weight, less than about 0.05% by weight, or less than about 0.01% by weight.

[0045] As used herein, the terms “substantially identical reference composition” or “substantially identical reference article” refer to a reference composition or article containing substantially identical components in the absence of the components of the present invention. In another exemplary embodiment, for example, the term “substantially” in the context of “substantially identical reference composition” includes a reference composition containing substantially identical components in which the components of the invention are replaced by components common in the art.

[0046] Furthermore, the terms “combined” and “associated” generally mean being combined or linked electrically, electromagnetically, and / or physically (e.g., mechanically or chemically), and do not exclude the existence of intermediate elements between the combined or associated items.

[0047] It will be understood that terms such as “first,” “second,” etc., may be used herein to describe various elements, components, areas, layers, and / or sections. These elements, components, areas, layers, and / or sections should not be limited by these terms. These terms are used solely to distinguish one element, component, area, layer, or section from another element, component, area, layer, or section. Accordingly, the first element, component, area, layer, or section discussed below may be referred to as the second element, component, area, layer, or section without departing from the teaching of the exemplary aspects.

[0048] The terms “layer” and “liner” are understood to be used synonymously. For the purposes of this disclosure, the term “outer jacket” is further understood to refer to an elongated tube having the composition and properties disclosed herein.

[0049] It is further understood that the terms "insertion force" and "pushing force" can be used synonymously.

[0050] Spatially relative terms such as “below,” “downward,” “below,” “upward,” “above,” and equivalents may be used herein to facilitate descriptions of the relationship between one element or feature illustrated in a figure and another element or feature. It will be understood that spatially relative terms are intended to encompass different orientations of the equipment during use or operation, in addition to the orientation depicted in the figure. For example, if the equipment in the figure is inverted, an element described as “below” or “downward” of another element or feature will be oriented “above” of the other element or feature. Thus, the term “downward” can encompass both upward and downward orientations. The equipment may be oriented in other ways (rotated by 90 degrees or in other orientations), and the spatially relative descriptors used herein shall be interpreted accordingly.

[0051] As used herein, the term "non-traumatic" refers to an instrument or procedure that is commonly known in the art and minimizes tissue damage.

[0052] As used herein, the terms “effective,” “effective amount,” or “effective conditions for…” refer to the amount or conditions that make it possible to carry out the function or property represented by the effective amount or conditions. As noted below, the exact amount or specific conditions required will vary depending on the known variables, such as the materials employed and the processing conditions observed. Therefore, it is not always possible to specify the exact “effective amount” or “effective conditions for…”. However, it should be understood that a suitable effective amount can be easily determined by those skilled in the art using only routine experiments.

[0053] The operation of exemplary embodiments of the disclosed methods may be described in a particular order for the sake of presentation; however, it should be understood that the disclosed embodiments may include operations in any order other than the specific order disclosed. For example, operations described sequentially may, in some cases, be rearranged or performed simultaneously. Furthermore, the descriptions and disclosures provided in relation to one particular embodiment are not limited to that embodiment and may apply to any disclosed embodiment.

[0054] While aspects of this disclosure may be described and claimed in certain legal fields, such as the systems legal field, this is for convenience only, and a person skilled in the art will understand that each aspect of this disclosure may be described and claimed in any legal field. Unless expressly stated otherwise, no method or aspect described herein is ever intended to be construed as requiring its steps to be performed in a specific order. Accordingly, if a claim for a method does not specifically state in the claim or description that the steps are limited to a specific order, the order is never intended to be inferred with respect to any point. This is effective for any possible implicit grounds for interpretation, including obvious meanings arising from the arrangement or flow of steps, grammatical structure or punctuation, or logical issues relating to the number or type of aspects described herein.

[0055] Furthermore, for simplicity, the accompanying diagrams may not show various ways in which the disclosed systems, methods, and apparatus can be used in combination with other systems, methods, and apparatus (which are readily apparent to those skilled in the art based on this disclosure). In addition, this description sometimes uses terms such as “produce” and “supply” to describe the disclosed methods. These terms are high-level abstractions of the actual operations that may be performed. The actual operations corresponding to these terms may vary depending on the specific implementation and are readily apparent to those skilled in the art based on this disclosure.

[0056] This disclosure may be more readily understood by referring to the following detailed descriptions of various aspects of this disclosure, as well as the examples contained herein, and the figures and their preceding and subsequent descriptions.

[0057] This disclosure may be more readily understood by referring to the following detailed descriptions of various aspects of this disclosure, as well as the examples contained herein, and the figures and their preceding and subsequent descriptions.

[0058] sheath The disclosed embodiments of an expandable sheath can minimize trauma to blood vessels by allowing temporary expansion of a portion of the introducer sheath to adapt to a delivery system, and then returning to its original diameter as the device passes through. In some embodiments, the sheath may comprise a smaller profile (e.g., a smaller diameter in a stationary configuration) than that of the introducer sheath of prior art. Furthermore, as disclosed herein, the sheath can reduce the length of time required for the procedure and reduce the risk of longitudinal or radial vascular laceration or plaque ablation because only one sheath is required, rather than several different sizes of sheaths. In certain embodiments, the expandable sheath can avoid the need for multiple insertions to dilate the vessel. Such expandable sheaths may be useful for many types of minimally invasive surgical procedures, such as any surgical procedure requiring the introduction of a device into a target vessel. For example, sheaths can be used to introduce other types of delivery devices for placing various types of intraluminal devices (e.g., stents, artificial heart valves, stented grafts, etc.) into many types of vascular and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary ducts, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.).

[0059] Furthermore, embodiments disclosed herein refer to sheaths having reduced insertion force compared to any other commercially available sheaths. As those skilled in the art will readily understand, reduced insertion force of the sheath and any medical device passing through it results in reduced or substantially eliminated risk to the patient during a medical procedure. It is understood that the insertion forces of the sheaths of the present invention, reference sheaths, and any other commercially available sheaths are measured using the same standardized techniques for appropriate comparison. In such embodiments, an Instron 3366 tensile testing machine has been used to measure the simulated insertion force required for an artificial valve to enter the sheath described. An additional condensation tube has been used to simulate vascular elasticity contributing to the pressing force. In certain exemplary embodiments, the test is performed in a water bath within a temperature range of room temperature to normal body temperature (e.g., about 20°C to less than about 40°C, but not limited thereto). The specimen can be kept in a linear configuration. The test can be performed using a tapered mandrel to simulate the valve entering the sheath.

[0060] Figure 1 shows a sheath 8 according to this disclosure, used with a typical delivery device 10 for delivering an artificial device 12, such as a tissue heart valve, to a patient. The device 10 may include a movable guide catheter 14 (also called a flex catheter), a balloon catheter 16 extending through the guide catheter 14, and a nasal catheter 18 extending through the balloon catheter 16. In the illustrated embodiment, the guide catheter 14, balloon catheter 16, and nasal catheter 18 are fitted to slide longitudinally relative to each other, as will be described in detail below, to facilitate the delivery and positioning of the valve (artificial device) 12 at the implantation site in the patient's body. Generally, the sheath 8 is inserted into a blood vessel, such as a transfemoral vessel, passing through the patient's skin, so that the distal end of the sheath 8 is inserted into the blood vessel. The sheath 8 may include a hemostatic valve at the opposite proximal end of the sheath. The delivery device 10 can be inserted into the sheath 8, and then the artificial device 12 can be delivered and implanted in the patient.

[0061] The present disclosure relates to various configurations of a sheath. These exemplary aspects are directed to a sheath for delivering a medical device, the sheath having a proximal end and a distal end, and being positioned at least at the proximal end of the sheath and extending along at least a portion of the length of the sheath, and comprising an elongate tube forming an outer layer of the sheath having an inner surface and an outer surface, the elongate tube comprising a first polymer layer, the first polymer layer being a first composite composition comprising a first polymer comprising greater than 0 wt% to less than 100 wt% of a polyether block amide, polyurethane, or a combination thereof, an inorganic filler of less than about 65% based on the total weight of the first composite composition, and a solid lubricant filler of up to about 20% based on the total weight of the first composite composition, the elongate tube being configured to reversibly expand from an initial diameter d0 in a non-expanded position to an expanded diameter d e up to upon passage of the medical device, and the sheath exhibits at least a 10% reduction in insertion force as compared to a substantially identical reference sheath that does not comprise the first polymer layer.

[0062] However, it is understood that aspects are also disclosed in which the disclosed sheath can comprise additional components. These exemplary aspects are disclosed herein as will be shown in detail below.

[0063] In certain aspects, the elongate tube comprises a first polymer layer. In such exemplary aspects, the first polymer layer can comprise a first composite composition comprising a polymer comprising greater than 0 wt% to less than 100 wt% of a polyether block amide, polyurethane, or any combination thereof, including exemplary values of about 0.01 wt%, about 1 wt%, about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 95 wt%, and about 99.9 wt%.

[0064] In further embodiments, the first composite composition may include a polymer comprising more than 35% by weight and less than 80% by weight of polyether block amides, polyurethanes, or any combination thereof, including exemplary values ​​of about 40% by weight, about 45% by weight, about 50% by weight, about 55% by weight, about 60% by weight, about 65% by weight, about 70% by weight, and about 75% by weight.

[0065] In certain embodiments, the polymer in the first composite composition comprises a polyether block amide. In such exemplary embodiments, the polyether block amide may include PEBAX® from Arkema. In even further embodiments, the polymer may include a polyurethane, such as NEUSoft®. In even further embodiments, the polymer may impair a combination of polyether block amides, such as PEBAX® and polyurethane. Where a mixture of polymers exists, it is further understood that such a mixture may contain each component in any amount relative to another component to provide a desired polymer within the scope disclosed above.

[0066] In further embodiments, the first composite composition may contain less than 65% by weight of inorganic fillers, based on the total weight of the first composite composition, including exemplary values ​​of inorganic fillers less than about 60% by weight, less than about 55% by weight, less than about 50% by weight, less than about 45% by weight, less than about 40% by weight, less than about 35% by weight, less than about 30% by weight, less than about 25% by weight, less than about 20% by weight, less than about 15% by weight, less than about 10% by weight, less than about 5% by weight, and less than 1% by weight.

[0067] In further embodiments, the inorganic filler may be present in an amount of at least about 1% by weight, at least about 2% by weight, at least about 5% by weight, at least about 10% by weight, at least about 15% by weight, at least about 20% by weight, at least about 25% by weight, at least about 30% by weight, at least about 35% by weight, at least about 40% by weight, at least about 45% by weight, at least about 50% by weight, or at least about 55% by weight.

[0068] In further embodiments, the inorganic filler may include any inorganic material that can be used as a filler and is permissible for the desired application. In certain exemplary and non-limiting embodiments, the inorganic filler may include bismuth chloride oxide, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof. Again, it is understood that the inorganic filler may include various combinations of fillers. In such exemplary embodiments, the amount of each filler in the combination may be within any range to provide a final combination that is within the range disclosed above.

[0069] In a further embodiment, the first composite composition may contain up to about 20% by weight of solid lubricating fillers, based on the total weight of the first composite compound, including exemplary values ​​of about 0.01% by weight, about 0.1% by weight, about 0.5% by weight, about 1% by weight, about 2% by weight, about 3% by weight, about 4% by weight, about 5% by weight, about 6% by weight, about 7% by weight, about 8% by weight, about 9% by weight, about 10% by weight, about 11% by weight, about 12% by weight, about 13% by weight, about 14% by weight, about 15% by weight, about 16% by weight, about 17% by weight, about 18% by weight, about 19% by weight, and about 19.9% ​​by weight. In an even further embodiment, the solid lubricating fillers may be present in up to about 20% by weight, up to about 15% by weight, or up to about 10% by weight, based on the total weight of the first composite composition.

[0070] In further embodiments, the solid lubricant filler may include any additives known to reduce friction and act as a lubricant. In such exemplary and non-limiting embodiments, the solid lubricant filler may include one or more of graphene, reduced graphene oxide, carbon black, boron nitride, silicone, talc, polytetrafluorinated polyethylene (PTFE), fluorinated ethylene propylene, and equivalents. In further embodiments, the solid lubricant includes a PTFE filler. In even further embodiments, the PTFE filler is a powder.

[0071] In further embodiments, the first composite composition may further comprise at least one tackiness-reducing compound. Any compound known in the art as capable of reducing the tackiness of a polymer composition may be considered and used for the purposes of this disclosure. In further exemplary and non-limiting embodiments, the at least one tackiness-reducing compound may include ProPell® from Foster Corporation.

[0072] In certain embodiments, at least one tackiness-reducing compound is present in an amount ranging from 0% to about 20% by weight, based on the total weight of the first composite compound, including exemplary values ​​of about 0.01% by weight, about 0.05% by weight, about 0.1% by weight, about 0.5% by weight, about 1% by weight, about 2% by weight, about 3% by weight, about 4% by weight, about 5% by weight, about 6% by weight, about 7% by weight, about 8% by weight, about 9% by weight, about 10% by weight, about 11% by weight, about 12% by weight, about 13% by weight, about 14% by weight, about 15% by weight, about 16% by weight, about 17% by weight, about 18% by weight, and about 19% by weight. In further embodiments, at least one tackiness-reducing compound is present in any amount having a value between any two of the aforementioned values. For example, but not limited to, at least one tackiness-reducing compound may be present in an amount of about 1% to about 5% by weight, or about 5% to about 10% by weight, based on the total weight of the first composite composition.

[0073] In further embodiments, as disclosed herein, the first polymer has substantially the same durometer along the entire length of the elongated tube. However, it is also understood that the durometer of the first polymer in the elongated tube may also vary along the length of the tube. For example, embodiments are disclosed herein, without limitation, in which the durometer of the first polymer at the proximal end of the elongated tube is different from that of the first polymer at the distal end of the elongated tube.

[0074] In a further embodiment, the first polymer in the first polymer layer has a Shore D of about 20D to about 72D, including exemplary values ​​of about 25D, about 30D, about 35D, about 40D, about 45D, about 50D, about 55D, about 60D, about 65D, and about 70D. In a further embodiment, the first polymer in the first polymer layer has a Shore D of about 20D to about 35D. In a further embodiment, the first polymer in the first polymer layer has a Shore D of about 30D. Furthermore, in a further embodiment, the first polymer in the first polymer layer has a Shore D of about 25D.

[0075] It is understood that the elongated tubes disclosed herein may include embodiments in which only one polymer layer is present. Furthermore, in other embodiments, two or more polymer layers may be present in the elongated tube. In such exemplary embodiments, the elongated tube comprises at least a second polymer layer comprising a second composite composition comprising a second polymer containing more than 0% to 100% by weight of a polyether block amide, polyurethane, or a composition thereof. Similar to the first composite composition, the second polymer may be present in any amount within the disclosed range. For example, the second polymer may be present in a second composite composition comprising a polymer containing polyether block amide, polyurethane, or any combination thereof in amounts of about 0% by weight, about 0.01% by weight, about 1% by weight, about 5% by weight, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, about 45% by weight, about 50% by weight, about 55% by weight, about 60% by weight, about 65% by weight, about 70% by weight, about 75% by weight, about 80% by weight, about 85% by weight, about 90% by weight, about 95% by weight, and about 99.9% by weight. In further embodiments, the second polymer may be present in the second composite composition in an amount greater than about 95% by weight and less than about 99% by weight, including exemplary values ​​of about 95.5% by weight, about 96% by weight, 96.5% by weight, about 97% by weight, about 97.5% by weight, about 98% by weight, and about 98.5% by weight.

[0076] In a further embodiment, the second composite composition may further include up to 20% by weight of a tackiness-reducing additive, based on the total weight of the second composite compound, including exemplary values ​​of about 0.01% by weight, about 0.05% by weight, about 0.1% by weight, about 0.5% by weight, about 1% by weight, about 2% by weight, about 3% by weight, about 4% by weight, about 5% by weight, about 6% by weight, about 7% by weight, about 8% by weight, about 9% by weight, about 10% by weight, about 11% by weight, about 12% by weight, about 13% by weight, about 14% by weight, about 15% by weight, about 16% by weight, about 17% by weight, about 18% by weight, and about 19% by weight. In a further embodiment, at least one tackiness-reducing compound is present in any amount having a value between any two of the aforementioned values. For example, but not limited to, at least one tackiness-reducing compound may be present in an amount of about 1% to about 5% by weight, or about 5% to about 10% by weight, based on the total weight of the second composite composition. In further embodiments, as disclosed herein, the second composite composition may be substantially free of solid lubricating fillers.

[0077] It is further understood that in certain embodiments, the first polymer in the first composite composition may be the same as the second polymer in the second composite composition. Furthermore, in other embodiments, the first polymer in the first composite composition may be different from the second polymer in the second composite composition. In even further embodiments, the second polymer layer may include PEBAX®. On the other hand, in even further embodiments, the second polymer layer may include polyurethane, for example, NEUSoft® from PolyOne.

[0078] In a further embodiment, the second polymer has a Shore D of about 20D to about 35D. Furthermore, in a further embodiment, the second polymer has a Shore D of about 25D or about 35D.

[0079] In further embodiments, the second composite composition may be substantially free of inorganic fillers. In certain embodiments, inorganic fillers may be present in the second composite composition in any amount greater than 0% by weight and less than 100% by weight, including exemplary values ​​of about 0.01% by weight, about 0.05% by weight, about 0.1% by weight, about 0.5% by weight, about 1% by weight, about 5% by weight, about 10% by weight, about 20% by weight, about 30% by weight, about 40% by weight, about 50% by weight, about 60% by weight, about 70% by weight, about 80% by weight, about 90% by weight, and about 95% by weight. In embodiments in which inorganic fillers are present in the second composite composition, such inorganic fillers may include any fillers disclosed above.

[0080] In further embodiments, as disclosed herein, the elongated tube has a predetermined thickness and comprises a first composite composition and / or a second composite composition, wherein at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or 100% of the predetermined thickness comprises a first polymer and / or a second polymer having a Shore D of about 30D or less.

[0081] In further embodiments, the predetermined thickness of the elongated tube may vary along the length of the sheath. On the other hand, in other embodiments, the predetermined thickness of the elongated tube is the same along the length of the sheath. Furthermore, in further embodiments, the predetermined thickness of the elongated tube is greater at the proximal end. In further embodiments, the predetermined thickness of the elongated tube is up to 6 mils and ranges from about 1 mil to about 6 mils, including, but not limited to, exemplary values ​​of about 1.5 mils, about 2 mils, about 2.5 mils, about 3 mils, about 3.5 mils, about 4 mils, about 4.5 mils, about 5 mils, about 5.5 mils, and about 5.9 mils.

[0082] In further embodiments, the first polymer layer and the second polymer layer may have the same thickness. On the other hand, in other embodiments, the first polymer layer and the second polymer layer may have different thicknesses. For example, in some embodiments, the first polymer layer may be about 1.1 mil, about 1.2 mil, about 1.3 mil, about 1.4 mil, about 1.5 mil, about 1.6 mil, about 1.7 mil, about 1.8 mil, about 1.9 mil, about 2.0 mil, 2.1 mil, about 2.2 mil, about 2.3 mil, about 2.4 mil, about 2.5 mil, about 2.6 mil, about 2.7 mil, about 2.8 mil, about 2.9 mil, about 3 Having a thickness of approximately 1 to 5 mils, including exemplary values ​​of 0.0 mil, approximately 3.1 mil, approximately 3.2 mil, approximately 3.3 mil, approximately 3.4 mil, approximately 3.5 mil, approximately 3.6 mil, approximately 3.7 mil, approximately 3.8 mil, approximately 3.9 mil, approximately 4.1 mil, approximately 4.2 mil, approximately 4.3 mil, approximately 4.4 mil, approximately 4.5 mil, approximately 4.6 mil, approximately 4.7 mil, approximately 4.8 mil, and approximately 4.9 mil. Furthermore, in a further embodiment, the second polymer layer may be 2.1 mil, approximately 2.2 mil, approximately 2.3 mil, approximately 2.4 mil, approximately 2.5 mil, approximately 2.6 mil, approximately 2.7 mil, approximately 2.8 mil, approximately 2.9 mil, approximately 3.0 mil, 3.1 mil, approximately 3.2 mil, approximately 3.3 mil, approximately 3.4 mil, approximately 3.5 mil, approximately 3.6 mil, approximately 3.7 mil, approximately 3.8 mil, approximately 3.9 mil, and approximately 4.0 mil It can have a thickness of approximately 2 to 6 mils, including exemplary values ​​of approximately 4.1 mils, approximately 4.2 mils, approximately 4.3 mils, approximately 4.4 mils, approximately 4.5 mils, approximately 4.6 mils, approximately 4.7 mils, approximately 4.8 mils, approximately 4.9 mils, approximately 5.1 mils, approximately 5.2 mils, approximately 5.3 mils, approximately 5.4 mils, approximately 5.5 mils, approximately 5.6 mils, approximately 5.7 mils, approximately 5.8 mils, and approximately 5.9 mils.

[0083] In a further embodiment, the predetermined thickness of the elongated tube is greater at the proximal end. On the other hand, in another embodiment, the predetermined thickness of the elongated tube is smaller at the distal end compared to the predetermined thickness of the elongated tube at the proximal end.

[0084] In a further embodiment where two or more layers are present in an elongated tube, the first polymer layer can define the inner surface of the elongated tube, while the second polymer layer can define the outer surface of the elongated tube. However, there are also embodiments in which the first polymer layer defines the outer surface of the elongated tube, while the second polymer layer defines the inner surface of the elongated tube. It is also understood that other embodiments include one or more additional polymer layers positioned between the first and second polymer layers.

[0085] In further embodiments, elongated tubes can be extruded. In embodiments where a first polymer layer and a second polymer layer are present, such polymer layers can be co-extruded. In further embodiments, the first polymer layer can be substantially bonded to the second polymer layer. In such exemplary embodiments, the first polymer layer does not peel substantially from the second polymer layer. In some embodiments, it is understood that the bonding may be physical, chemical, or any other type known in the art.

[0086] In further embodiments, any sheath comprising an elongated tube as disclosed herein may exhibit at least about 10%, at least about 15%, at least 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50% reduction in insertion force compared to a substantially identical reference sheath without the first polymer layer.

[0087] In further embodiments, any sheath comprising an elongated tube as disclosed herein may exhibit an insertion force of less than approximately 55 N, less than approximately 50 N, less than approximately 45 N, less than approximately 40 N, less than approximately 35 N, or less than approximately 35 N when a medical device is pushed through the sheath.

[0088] In further embodiments, the elongated tube may also exhibit a frictional force of less than about 10 N, less than about 9 N, less than about 8 N, less than about 7 N, less than about 6 N, or even less than about 5 N in a dry state against a substrate surface having a diameter of about 0.300 inches and containing one or more of polytetrafluoroethylene, fluorinated ethylene propylene, or high-density polyethylene.

[0089] In further embodiments, the elongated tube may exhibit a hoop force at approximately 10 mm elongation (approximately 85% strain) of less than approximately 10 N, or less than approximately 9 N, or less than approximately 8 N, or less than approximately 7 N, or less than approximately 6 N, or even less than approximately 5 N. In such exemplary embodiments, the elongated tube may have a diameter of approximately 0.290 inches (7.4 mm) and the wall thickness disclosed herein. In embodiments in which the elongated tube has a diameter of approximately 0.290 inches (7.4 mm) and a total wall thickness of approximately 0.0045 inches, along with a sample length of approximately 0.25 inches (6.4 mm), the hoop force at 10 mm elongation may be less than approximately 8 N. In some exemplary and non-limiting embodiments, it is understood that a lower force at 10 mm elongation is desired for a lower sheath expansion force.

[0090] In further embodiments, the elongated tube may exhibit a fracture elongation in the range of approximately 650% to approximately 800%, including exemplary values ​​of approximately 680%, approximately 700%, approximately 710%, approximately 750%, and approximately 780%. In some exemplary and non-limiting embodiments, it is understood that a higher elongation is preferable for the elongated tube to expand to a larger diameter before breaking.

[0091] In a further embodiment, the elongated tube is substantially torsion-resistant.

[0092] In certain embodiments, the elongated tube extends along a portion of the length of the sheath. In such exemplary embodiments, the elongated tube may be located at the proximal end of the sheath, in the middle of the sheath, or in the distal portion of the sheath. On the other hand, in other embodiments, the elongated tube extends along the entire length of the sheath. In such exemplary embodiments, the elongated tube may be located at the proximal end of the sheath and extend to the distal end of the sheath.

[0093] Furthermore, the sheath may further comprise an expandable tubular inner liner extending along the length of the sheath and having at least one folded portion, wherein the expandable inner liner has an inner surface and an outer surface, the inner surface of the expandable inner liner defining a lumen and forming the inner surface of at least one folded portion, and the outer surface extending circumferentially and forming the outer surface of at least one folded portion; and a first outer tubular layer extending at least partially along the length of the sheath and having an inner surface and an outer surface, wherein the inner surface of the first outer tubular layer further extends at least partially around the outer surface of the inner liner such that at least a portion of the inner surface of the first outer tubular layer is positioned adjacent to the outer surface of at least one folded portion of the inner liner, and an elongated tube is positioned such that at least a portion of the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer.

[0094] In further embodiments, the elongated tube disclosed herein may comprise at least two polymer layers. In further embodiments, the elongated tube disclosed herein may comprise at least one intermediate reinforcing layer disposed between the first polymer layer and the second polymer layer. In further embodiments, the at least one intermediate reinforcing layer is a polymer layer.

[0095] In some embodiments, at least one intermediate layer can extend along the entire circumference of the elongated tube. In a further embodiment, the intermediate layer is positioned between the outer surface of the first polymer and the inner surface of the second polymer layer, where the first polymer layer forms the inner surface of the elongated tube and the second polymer layer forms the outer surface of the elongated tube. In another embodiment, as disclosed above, the intermediate layer is positioned between the outer surface of the second polymer layer and the inner surface of the first polymer layer, where the second polymer layer forms the inner surface of the elongated tube and the first polymer layer forms the outer surface of the elongated tube. In yet another embodiment, the intermediate reinforcing layer can bond the first and second polymer layers and can also assist in bonding the elongated tube as a whole to the inner member of the sheath.

[0096] In a further embodiment, at least one intermediate layer has a finite width smaller than the circumference of the elongated tube. In such an embodiment, at least one intermediate layer can be inserted as a strip between the first polymer layer and the second polymer layer. In some exemplary and non-limiting embodiments, if the elongated tube has a distal outer diameter of about 0.200 inches, the strips may have widths ranging from about 0.010 inches to about 0.150 inches, including exemplary values ​​of about 0.03 inches, about 0.035 inches, about 0.04 inches, about 0.045 inches, about 0.05 inches, about 0.055 inches, about 0.06 inches, about 0.065 inches, about 0.07 inches, about 0.075 inches, about 0.08 inches, about 0.085 inches, about 0.09 inches, about 0.095 inches, about 0.10 inches, about 0.105 inches, about 0.110 inches, about 0.115 inches, about 0.120 inches, about 0.125 inches, about 0.130 inches, about 0.135 inches, about 0.140 inches, and about 0.145 inches. The widths shown above are illustrative, and it should be understood that if the distal outer diameter of the elongated sheath is a different size from 0.200 inches, the strip width may be adjusted by the same or a different ratio.

[0097] In further embodiments, at least one intermediate layer has a finite width smaller than the circumference of the elongated tube. In such embodiments, at least one intermediate layer can be inserted as a strip between the first polymer layer and the second polymer layer. In some exemplary and non-limiting embodiments, if the elongated tube has a distal outer diameter of about 0.200 inches, the strip may have a width of about 5% to about 50% of the circumference of the elongated tube. In further embodiments, the combined width of the strips may be about 5%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50% of the circumference of the elongated tube. The widths shown above are exemplary, and it should be understood that if the distal outer diameter of the elongated sheath is of a size different from 0.200 inches, the strip width may be adjusted by the same or different proportions.

[0098] In a further embodiment, the elongated tube may comprise two or more intermediate layers. In such an embodiment, the two or more intermediate layers may be arranged circumferentially between the first polymer layer and the second polymer layer as individual strips at a predetermined distance from each other. In the embodiment in which the two or more intermediate layers are arranged between the first polymer layer and the second polymer layer of the elongated tube, the combined width of all the strips is approximately 5% to approximately 50% of the circumference of the elongated tube. In a further embodiment, the combined width of the strips is approximately 5%, approximately 15%, approximately 20%, approximately 25%, approximately 30%, approximately 35%, approximately 40%, approximately 45%, or approximately 50% of the circumference of the elongated tube.

[0099] In a further embodiment, at least one intermediate layer is configured to provide axial reinforcement to the elongated tube, and as a result, to a sheath through which the elongated tube can be used. In such exemplary embodiments, at least one intermediate layer may be positioned along the length of the elongated tube, or along a portion of the length of the elongated tube.

[0100] In some embodiments, a portion of the length of the elongated tube in which at least one intermediate layer is located is situated at the distal and / or proximal ends of the elongated tube. In yet another embodiment, at least one intermediate layer may also be located at any point along the length of the elongated tube.

[0101] In embodiments where the intermediate layer exists as one or more strips arranged circumferentially along the length of the sheath, it is further understood that the width of the strips may be the same along the length or may vary along the length. In embodiments where the width of the strips varies along the length of the elongated tube, such strips may have any of the width values ​​disclosed above.

[0102] In further embodiments, the first polymer layer used in this exemplary elongated tube may be any of the first polymer layers described above. In further exemplary and non-limiting embodiments, the first polymer layer forms the inner surface of the elongated tube and comprises a first composite composition comprising, based on the total weight of the first composite composition, a first polymer comprising more than 0% to 100% by weight of polyether block amide, polyurethane, or a combination thereof; less than about 65% by weight of inorganic filler; and up to about 20% by weight of solid lubricating filler.

[0103] Any of the inorganic fillers and solid lubricant fillers disclosed above may be present in any disclosed amount. For example, the inorganic fillers may include bismuth chloride oxide, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof. In yet another embodiment, the inorganic filler may be present in at least 10% by weight. In yet another embodiment, the inorganic filler may be present in an amount of less than about 50% by weight based on the total weight of the first composite composition.

[0104] In further embodiments, the solid lubricant filler may include a PTFE filler.

[0105] The first compound may also contain any of the additives disclosed above. For example, the compound may contain at least one tackiness-reducing compound in an amount of about 1% to about 20% by weight.

[0106] In further exemplary embodiments, the polymer present in the first compound may have a Shore D of about 20D to about 35D, including exemplary values ​​of about 22D, about 25D, about 27D, about 30D, and about 32D.

[0107] In a further embodiment, the durometer of the first polymer in the first polymer layer at the proximal end of the elongated tube may differ from the durometer of the first polymer in the first polymer layer at the distal end of the elongated tube.

[0108] In further embodiments, the polymer in the first compound may include a polyether block amide, such as PEBAX®. On the other hand, in other embodiments, the polymer in the first compound may include a polyurethane. In even further embodiments, the first compound may also include a polyamide.

[0109] In further embodiments, the thickness of the first polymer layer is approximately 1.1 mil, approximately 1.2 mil, approximately 1.3 mil, approximately 1.4 mil, approximately 1.5 mil, approximately 1.6 mil, approximately 1.7 mil, approximately 1.8 mil, approximately 1.9 mil, approximately 2.0 mil, 2.1 mil, approximately 2.2 mil, approximately 2.3 mil, approximately 2.4 mil, approximately 2.5 mil, approximately 2.6 mil, approximately 2.7 mil, approximately 2.8 mil, approximately 2.9 mil, approximately It can range from approximately 1 to approximately 5 mils, including exemplary values ​​of 3.0 mils, approximately 3.1 mils, approximately 3.2 mils, approximately 3.3 mils, approximately 3.4 mils, approximately 3.5 mils, approximately 3.6 mils, approximately 3.7 mils, approximately 3.8 mils, approximately 3.9 mils, approximately 4.1 mils, approximately 4.2 mils, approximately 4.3 mils, approximately 4.4 mils, approximately 4.5 mils, approximately 4.6 mils, approximately 4.7 mils, approximately 4.8 mils, and approximately 4.9 mils.

[0110] In further embodiments, the second polymer layer may include any of the polymers disclosed above. In some embodiments, the second polymer layer may include a second composite composition comprising the second polymer, which comprises more than 0% to 100% by weight of a polyether block amide, polyurethane, or a composition thereof. In further embodiments, the second polymer layer may include a polyamide. In some other embodiments, the second compound may also include any of the fillers or additives disclosed above. On the other hand, in some embodiments, the second compound may not contain any solid lubricating fillers disclosed herein. On the other hand, in further embodiments, the second compound may contain any tackiness-reducing additives described herein. In some embodiments, the second polymer may be a polyurethane. In further embodiments, the polyurethane may be a thermoplastic polyurethane. On the other hand, in further embodiments, the second polymer may be a blend containing polyurethane together with a styrene block copolymer. In further embodiments, the blend may further include additional polymers and copolymers. For example, an ether polymer may be present in the blend. In some exemplary and non-limiting embodiments, the second polymer may be selected from commercially available polymers sold under the trade name Neusoft®. In even further embodiments, the second polymer may have a Shore A durometer of about 20A to about 75A, including exemplary values ​​of about 25A, about 30A, about 35A, about 40A, about 45A, about 50A, about 55A, about 60A, about 65A, and about 70A. In even further embodiments, the second polymer may have a Shore A durometer of less than 60A. In some exemplary embodiments, the second polymer may be Neusoft® 597-50A.

[0111] In further embodiments, the thickness of the second polymer layer is approximately 1.1 mil, 1.2 mil, 1.3 mil, 1.4 mil, 1.5 mil, 1.6 mil, 1.7 mil, 1.8 mil, 1.9 mil, 2.0 mil, 2.1 mil, 2.2 mil, 2.3 mil, 2.4 mil, 2.5 mil, 2.6 mil, 2.7 mil, 2.8 mil, 2.9 mil, 3.0 mil, 3.1 mil, 3.2 mil, 3.3 mil, and 3.4 mil. The values ​​can range from approximately 1 to approximately 6 mils, including exemplary values ​​of approximately 3.5 mils, 3.6 mils, 3.7 mils, 3.8 mils, 3.9 mils, 4.1 mils, 4.2 mils, 4.3 mils, 4.4 mils, 4.5 mils, 4.6 mils, 4.7 mils, 4.8 mils, 4.9 mils, 5.1 mils, 5.2 mils, 5.3 mils, 5.4 mils, 5.5 mils, 5.6 mils, 5.7 mils, 5.8 mils, and 5.9 mils. In further embodiments, the thickness of at least one intermediate reinforcement layer is approximately 1.1 mil, approximately 1.2 mil, approximately 1.3 mil, approximately 1.4 mil, approximately 1.5 mil, approximately 1.6 mil, approximately 1.7 mil, approximately 1.8 mil, approximately 1.9 mil, approximately 2.0 mil, 2.1 mil, approximately 2.2 mil, approximately 2.3 mil, approximately 2.4 mil, approximately 2.5 mil, approximately 2.6 mil, approximately 2.7 mil, approximately 2.8 mil, approximately 2.9 mil, approximately 3.0 mil, approximately 3.1 mil, approximately 3.2 mil, approximately 3.3 mil, approximately 3 It can range from approximately 1 mil to approximately 6 mil, including exemplary values ​​of 0.4 mil, approximately 3.5 mil, approximately 3.6 mil, approximately 3.7 mil, approximately 3.8 mil, approximately 3.9 mil, approximately 4.1 mil, approximately 4.2 mil, approximately 4.3 mil, approximately 4.4 mil, approximately 4.5 mil, approximately 4.6 mil, approximately 4.7 mil, approximately 4.8 mil, approximately 4.9 mil, approximately 5.1 mil, approximately 5.2 mil, approximately 5.3 mil, approximately 5.4 mil, approximately 5.5 mil, approximately 5.6 mil, approximately 5.7 mil, approximately 5.8 mil, and approximately 5.9 mil.

[0112] In further embodiments, at least one intermediate layer may include any of the polymers disclosed herein. In some embodiments, at least one intermediate layer may include the first compound disclosed above. In other embodiments, at least one intermediate layer may include the second compound disclosed above. On the other hand, in further embodiments, at least one intermediate layer may include the first compound. Furthermore, in further embodiments, at least one intermediate layer may include any polymer known in the art and suitable for the desired application. In some embodiments, at least one intermediate layer may include a polyether block amide, a polyurethane, or a combination thereof. On the other hand, in further embodiments, at least one intermediate layer may be a polyether block amide, e.g., PEBAX®. On the other hand, in further embodiments, the intermediate layer may be a polyurethane. In such exemplary embodiments, at least one intermediate layer may not contain a solid lubricating filler such as PTFE. In yet another embodiment, at least one intermediate layer may not contain an inorganic filler. In further embodiments, at least one intermediate layer may include a polymer comprising PEBAX® or polyurethane having a Shore D (or Shore A) durometer of about 45D (85A) to about 90D, including exemplary values ​​of about 50D, about 55D, about 60D, about 65D, about 70D, about 72D, about 75D, about 80D, and about 85D.

[0113] In further embodiments, at least one intermediate reinforcing layer may include polyolefin. In even further embodiments, at least one intermediate reinforcing layer may include polyethylene, polypropylene, graft-modified polyethylene, or polypropylene. In even further embodiments, at least one intermediate reinforcing layer may include grafted low-density polyethylene (LDPE), grafted medium-density polyethylene, grafted ultra-low-density polyethylene (ULDPE), grafted high-density polyethylene (HDPE), grafted heterogeneously branched linear low-density polyethylene (LLDPE), grafted homogeneously branched linear ethylene polymer and substantially linear ethylene polymer, grafted polypropylene, or ethylene vinyl acetate (EVA), or any combination thereof. In such exemplary embodiments, maleic anhydride or acrylic acid may be used to graft the polymers disclosed above. In even further embodiments, at least one intermediate reinforcing layer may include maleic anhydride or acrylic acid-grafted low-density polyethylene. In even further embodiments, at least one intermediate reinforcing layer may include maleic anhydride or acrylic acid-grafted polypropylene. In further embodiments, at least one intermediate reinforcing layer may include maleic anhydride or acrylic acid grafted ethylene vinyl acetate. In even further embodiments, at least one intermediate reinforcing layer may include maleic anhydride grafted polyolefin sold under the trade name OREVAC®.

[0114] In a further embodiment, any of the at least one intermediate reinforcing layer disclosed above can thermally bond an elongated tube to the inner member of the sheath. In a further embodiment, the intermediate reinforcing layer can be extruded so as to be positioned between the first polymer layer and the second polymer layer. In a further embodiment, at least one intermediate reinforcing layer can be fused with the first and second polymer layers by at least one of heat or compression.

[0115] In further embodiments, the elongated tubes disclosed herein, comprising at least one intermediate reinforcing layer, may exhibit expansion forces of less than about 50 N, less than about 49 N, less than about 48 N, less than about 47 N, less than about 46 N, less than about 45 N, less than about 44 N, less than about 43 N, less than about 42 N, less than about 41 N, or even less than about 40 N.

[0116] In further embodiments, the elongated tubes disclosed herein, comprising at least one intermediate reinforcing layer, may exhibit burst pressures of approximately 8 psi, approximately 8.5 psi, approximately 9 psi, approximately 9.5 psi, approximately 10 psi, approximately 10.5 psi, approximately 11 psi, approximately 11.5 psi, approximately 12 psi, approximately 12.5 psi, approximately 13 psi, approximately 13.5 psi, approximately 14 psi, approximately 14.5 psi, or approximately 15 psi.

[0117] Figures 2A, 2B, and 2D show cross-sectional views of the sheath 22 for use with a delivery device such as the one shown in Figure 1. The exemplary expandable sheath is also described in U.S. Patent Application No. 12 / 249,867 (currently U.S. Patent No. 8,690,936) filed on October 10, 2008; U.S. Patent Application No. 13 / 312,739 (currently U.S. Patent No. 8,790,387) filed on December 6, 2011; U.S. Patent Application No. 14 / 248,120 (currently U.S. Patent No. 9,301,840) filed on April 8, 2014; U.S. Patent Application No. 14 / 324,894 (currently U.S. Patent No. 9,301,841) filed on July 7, 2014; and U.S. Patent Application No. 15 / 057,953 (currently U.S. Patent No. 9,987,134) filed on March 1, 2016. This information is also disclosed in U.S. Patent Application No. 15 / 997,587 filed on 4 June 2018, U.S. Patent Application No. 16 / 149,953 (currently U.S. Patent No. 10,524,905) filed on 2 October 2018, U.S. Patent Application No. 16 / 149,956 (currently U.S. Patent No. 10,517,720) filed on 2 October 2018, U.S. Patent Application No. 16 / 149,960 (currently U.S. Patent No. 10,524,906) filed on 2 October 2018, and U.S. Patent Application No. 16 / 149,969 (currently U.S. Patent No. 10,524,907) filed on 2 October 2018, and that disclosure is incorporated herein by reference.

[0118] Figure 2C shows a perspective view of one embodiment of an inner layer (or tubular inner liner) 24 for use with a sheath 22. The sheath 22 comprises an inner layer, such as an inner polymer tubular liner 24, and an outer layer, such as an outer polymer tubular layer 26. The sheath may also include an intermediate tubular layer 28 positioned between the inner and outer polymer tubular layers (liners) 24, 26. The sheath 22 defines a lumen 30 through which a delivery device can advance into the patient's blood vessels for the purpose of delivering, removing, repairing, and / or replacing the prosthesis. Such an introduction device sheath 22 may also be useful for other types of minimally invasive surgery, such as any surgical procedure requiring the introduction of a device into the blood vessel of the target. For example, sheath 22 can also be used to introduce other types of delivery devices for placing various types of intraluminal devices (e.g., stents, stented grafts, etc.) into many types of vascular and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary ducts, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.).

[0119] The outer polymer tubular layer 26 and the inner polymer tubular liner 24 may include, for example, polytetrafluoroethylene (PTFE) (e.g., Teflon®), polyimide, PEEK, polyurethane, nylon, polyethylene, polyamide, polyether block amide (e.g., PEBAX®), polyether block ester copolymer, polyester, fluoropolymer, polyvinyl chloride, thermosetting silicone, latex, polyisoprene rubber, polyolefin, other medical-grade polymers, or combinations thereof. In yet another embodiment, the outer tubular layer may also include high-density polyethylene (HDPE).

[0120] The intermediate tubular layer 28 may include shape memory alloys such as nitinol and / or stainless steel, cobalt-chromium, Spectra fibers, polyethylene fibers, aramid fibers, or combinations thereof.

[0121] The inner polymer tubular liner 24 can be advantageously provided with a low coefficient of friction on its inner surface. For example, the inner polymer tubular liner 24 may have a coefficient of friction of less than about 0.5, less than about 0.1, less than about 0.05, or even less than about 0.01. Some embodiments of the sheath 22 may include an additional lubricating liner on the inner surface 32 of the inner polymer tubular liner 24. Such a liner can facilitate the passage of a delivery device through the lumen 30 of the sheath 22. Examples of suitable lubricating liners include materials that can reduce the coefficient of friction of the inner polymer tubular liner 24, such as PTFE, polyethylene, polyvinylidene fluorine, and combinations thereof. Suitable materials for the lubricating liner also include other materials, preferably having a coefficient of friction of less than about 0.5, less than about 0.1, less than about 0.05, or even less than about 0.01.

[0122] The inner diameter of the intermediate tubular layer 28 varies depending on the application and size of the delivery device and prosthesis. In some embodiments, the inner diameter ranges from approximately 0.005 inches to approximately 0.400 inches, including exemplary values ​​of approximately 0.01 inches, approximately 0.05 inches, approximately 0.100 inches, approximately 0.120 inches, approximately 0.150 inches, approximately 0.170 inches, approximately 0.200 inches, approximately 0.220 inches, approximately 0.250 inches, approximately 0.270 inches, approximately 0.300 inches, approximately 0.320 inches, approximately 0.350 inches, and approximately 0.370 inches.

[0123] The thickness of the intermediate tubular layer 28 can be varied depending on the desired amount of radial expansion and the required strength. For example, the thickness of the intermediate tubular layer 28 may range from about 0.002 inches to about 0.0025 inches, including exemplary values ​​of about 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches, 0.009 inches, about 0.010 inches, about 0.011 inches, about 0.012 inches, about 0.013 inches, about 0.014 inches, about 0.015 inches, about 0.016 inches, about 0.017 inches, about 0.018 inches, 0.019 inches, about 0.020 inches, about 0.021 inches, about 0.022 inches, about 0.023 inches, and about 0.024 inches.

[0124] The thicknesses of the inner polymer tubular liner 24 and the outer polymer tubular layer 26 may also be varied depending on the specific application of the sheath 22. In some embodiments, the thickness of the inner polymer tubular liner 24 is in the range of about 0.0005 inches to about 0.010 inches, including exemplary values ​​of about 0.0006 inches, about 0.0007 inches, about 0.0008 inches, about 0.0009 inches, about 0.001 inches, about 0.002 inches, 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches, and about 0.009 inches. In one embodiment, the thickness may be about 0.002 inches. The outer polymer tubular layer 26 can have a thickness of approximately 0.002 inches to approximately 0.015 inches, including exemplary values ​​of approximately 0.003 inches, approximately 0.004 inches, approximately 0.005 inches, approximately 0.006 inches, approximately 0.007 inches, approximately 0.008 inches, 0.009 inches, approximately 0.010 inches, approximately 0.011 inches, approximately 0.012 inches, approximately 0.013 inches, and approximately 0.014 inches. In certain embodiments, the outer polymer tubular layer 26 can have a thickness of approximately 0.010 inches.

[0125] The hardness of each layer of the sheath 22 can also be modified depending on the specific application and desired properties of the sheath 22. In some embodiments, the outer polymer tubular layer 26 has a Shore D durometer of about 25D to about 75D.

[0126] In addition, some embodiments of the sheath 22 may include an external hydrophilic coating on the outer surface 34 of the outer polymer tubular layer 26. Such a hydrophilic coating can facilitate the insertion of the sheath 22 into the patient's blood vessels. Examples of suitable hydrophilic coatings include Harmony® Advanced Lubricity Coating and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM Medical Coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings, are also suitable for use with the sheath 22.

[0127] In some embodiments, the outer surface 34 of the outer polymer tubular layer 26 can be modified. For example, surface modification such as plasma etching can be performed on the outer surface 34. Similarly, other surfaces, both outer and inner, can be modified according to specific embodiments and desired applications. In some embodiments, surface modification can improve interlayer adhesion within the modified area.

[0128] In certain embodiments, the outer surface of the first outer tubular layer can be etched at least partially. In even further embodiments, the outer surface of the inner liner can be selectively etched around the circumference, linearly along at least a portion of the length of the sheath, or a combination thereof.

[0129] The sheath 22 may also have at least one radiopaque filler or marker. The radiopaque filler or marker may be associated with the outer surface 34 of the outer polymer tubular layer 26. Alternatively, the radiopaque filler or marker may be embedded within or blended into the outer polymer tubular layer 26. Similarly, the radiopaque filler or marker may be associated with the surface of the inner polymer tubular liner 24 or the intermediate tubular layer 28, or embedded within either or both of these layers.

[0130] Suitable materials for use as radiopaque fillers or markers include, for example, barium sulfite, bismuth trioxide, titanium dioxide, bismuth subcarbonate, or combinations thereof. The radiopaque filler may be mixed with or embedded in the material used to form the outer polymer tubular layer 26 and may contain approximately 5% to 45% by weight, including exemplary values ​​of approximately 10% by weight, approximately 15% by weight, approximately 20% by weight, approximately 30% by weight, approximately 35% by weight, and approximately 40% by weight of the outer polymer tubular layer. Depending on the specific application, more or less radiopaque material may be used in several embodiments.

[0131] In some embodiments, the inner polymer tubular liner 24 may include a substantially uniform cylindrical tube. In alternative embodiments, the inner polymer tubular liner 24 may have at least one discontinuous section along its longitudinal axis to facilitate radial expansion of the inner polymer tubular liner 24. For example, the inner polymer tubular liner 24 may be provided with one or more longitudinal notches and / or cuts 36 extending along at least a portion of the length of the sheath 22. Such notches or cuts 36 facilitate radial expansion of the inner polymer tubular liner 24 and thus can adapt to the passage of a delivery device or other equipment. Such notches and / or cuts 36 may be provided near the inner surface 32, near the outer surface 37, and / or substantially throughout the entire thickness of the inner polymer tubular liner 24. In embodiments having multiple notches and / or cuts 36, such notches and / or cuts 36 may be positioned so as to be substantially evenly spaced from each other around the circumferential direction of the inner polymer tubular liner 24. Alternatively, the notches and cuts 36 may be spaced randomly relative to each other or in any other desired pattern. Some or all of any provided notches and / or cuts 36 may extend longitudinally substantially along the entire length of the sheath 22. Alternatively, some or all of any provided notches and / or cuts 36 may extend longitudinally only along a portion of the length of the sheath 22.

[0132] As shown in Figures 2B and 2C (showing only the inner polymer tubular liner 24), in some embodiments, the inner polymer tubular liner 24 includes at least one notch or notch 36 that extends longitudinally and parallel to the axis defined by the lumen 30, substantially along the entire length of the sheath 22. Thus, upon introduction of the delivery device, the inner polymer tubular liner 24 cleaves and expands along the notch and / or notch 36, and is therefore able to adapt to the delivery device.

[0133] In addition, or alternatively, as shown in Figure 2D, the outer polymer tubular layer 26 may be provided with one or more notches and / or cuts 36. In some embodiments, the notches and / or cuts 36 do not extend throughout the entire thickness of the outer polymer tubular layer 26. The notches and / or cuts 36 may be separable when the sheath 22 is radially expanded. The outer polymer tubular layer 26 may be retractable longitudinally or retractable from the intermediate tubular layer 28 and the inner polymer tubular liner 24. In embodiments having a retractable outer polymer tubular layer 26, the outer polymer tubular layer 26 may be retracted to adapt to or facilitate passage of a delivery device through the lumen and then repositioned to its original position on the sheath 22.

[0134] Figure 3 shows an elevation view of the sheath 22 shown in Figure 2A. In this figure, only the outer polymer tubular layer 26 is visible. The sheath 22 comprises a proximal end 38 and a distal end 40 opposite the proximal end 38. The sheath 22 may include a hemostatic valve inside the lumen of the sheath 22 at or near the proximal end 38 of the sheath 22.

[0135] In addition, the sheath 22 may be provided with a soft tip 42 at the distal end 40 of the sheath 22. Such a soft tip 42 may provide a lower hardness than the rest of the sheath 22. In some embodiments, the soft tip 42 may have a Shore hardness of about 25D to about 40D, comprising a polymer having a Shore hardness of about 30D or about 35D.

[0136] As shown in Figure 3, the original, unexpanded outer diameter of the sheath 22 may be substantially constant over the length of the sheath 22, substantially from the proximal end 38 to the distal end 40. In alternative embodiments, such as those shown in Figures 4A and 4B, the original, unexpanded outer diameter of the sheath 22 may decrease from the proximal end 38 to the distal end 40. As shown in the embodiment of Figure 4A, the original, unexpanded outer diameter may decrease along a gradient from the proximal end 38 to the distal end 40. In alternative embodiments, such as those shown in Figure 4B, the original, unexpanded outer diameter of the sheath 22 may decrease incrementally along the length of the sheath 22, with the largest original, unexpanded outer diameter near the proximal end 38 and the smallest original, unexpanded outer diameter near the distal end 40 of the sheath 22.

[0137] As shown in Figures 5-6, the sheath 22 may be designed to expand locally as the prosthesis passes through the lumen of the sheath 22, and then substantially return to its original shape as the prosthesis passes through that portion of the sheath 22. For example, Figure 5 illustrates the sheath 22 with a localized bulge 44 representing the device passing through the internal lumen of the sheath 22. Figure 5 shows the device near the proximal end 38 of the sheath 22, close to the area where the device is introduced into the sheath 22. Figure 6 shows the sheath 22 of Figure 5 as the device has advanced further along the sheath 22. The localized bulge 44 is now closer to the distal end 40 of the sheath 22 and is therefore about to be introduced into the patient's blood vessel. As is evident from Figures 5 and 6, as the localized bulge associated with the device passes through a portion of the lumen of the sheath 22, that portion of the sheath 22 can automatically return to its original shape and size, at least partially due to the material and structure of the sheath b.

[0138] The sheath 22 has a non-expandable inner diameter equal to the inner diameter of the inner polymer tubular liner (not visible in Figures 5-6) and a non-expandable outer diameter 46 equal to the outer diameter of the outer polymer tubular layer 26. The sheath 22 is designed to expand to an expanded inner diameter and an expanded outer diameter 48, which are larger than the non-expandable inner diameter and non-expandable outer diameter 46, respectively. In one typical embodiment, the non-expandable inner diameter is approximately 16 Fr and the non-expandable outer diameter 46 is approximately 19 Fr, while the expanded inner diameter is approximately 26 Fr and the expanded outer diameter 48 is approximately 29 Fr. Different sheaths 22 may provide different expanded and non-expandable inner and outer diameters depending on the size requirements of the delivery device for various applications. In addition, some embodiments may provide more or less expansion depending on the specific design parameters, materials, and / or configuration used.

[0139] In some embodiments of the sheath according to this disclosure, the sheath 22 comprises an outer cover (or second outer layer) 50 formed by elongated tubes disclosed herein, as shown in the cross-sectional view of Figure 7 and the elevation view of Figure 8. In such embodiments, the elongated tubes may be positioned such that at least a portion of the inner surface of the elongated tubes covers at least a portion of the outer surface 52 of the first outer tubular layer 26. In such embodiments where the elongated tubes 50 are present and form the outer cover (or outermost layer), the outer tubular layer 26 may also be referred to as the first outer tubular layer 26, while the elongated tubes may be referred to as the second. The outer polymer cover 50 can provide a protective cover for the lower sheath 22. In some embodiments, the outer polymer cover 50 includes a self-expanding sheath in a compressed or constrained state, which can then be released when the outer polymer cover 50 is removed.

[0140] For example, in some embodiments of the self-expandable sheath, the intermediate tubular layer 28 may contain nitinol and / or other shape memory alloys, and the intermediate tubular layer 28 may be compressed to a reduced diameter or radially compressed within the outer polymer tubular layer 26 and outer polymer cover 50. Once the self-expandable sheath is at least partially inserted into the patient's blood vessel, the outer polymer cover 50 can be slid backward, peeled off, or otherwise partially removed from the sheath. To facilitate the removal of the outer polymer cover 50, a portion of the outer polymer cover 50 may remain outside the patient's blood vessel, and that portion may be pulled back or removed from the sheath to allow the sheath to expand. In some embodiments, substantially the entire outer polymer cover (the elongated tube disclosed herein) 50 may be inserted into the patient's blood vessel together with the sheath. In these embodiments, an external mechanism can be provided attached to the outer polymer cover 50 so that, once the sheath is inserted into the patient's blood vessel, the outer polymer cover can be at least partially removed from the sheath.

[0141] In some embodiments, once the radially compressed intermediate layer 28 is no longer constrained by the outer polymer cover 50, it can self-expand, causing the sheath to expand along the length of the intermediate tubular layer 28. In some embodiments, portions of the sheath can collapse radially as the sheath is withdrawn from the blood vessel after the completion of the surgical procedure, returning at least partially to their original compressed state. In some embodiments, such collapse can be facilitated and / or encouraged by additional devices or layers, which in some embodiments may be mounted on portions of the sheath before insertion of the sheath into the blood vessel.

[0142] In some embodiments, the outer polymer cover 50 is not bonded to other layers of the sheath 22. For example, the outer polymer cover 50 may be slidable relative to the lower sheath so that it can be easily removed or stored from its initial position on the sheath 22.

[0143] Suitable materials for the outer polymer cover 50 are disclosed in detail above.

[0144] Turning our attention to the intermediate tubular layer 28, several different configurations are possible. The intermediate tubular layer 28 is generally a thin, hollow, substantially cylindrical tube containing an arrangement, pattern, structure, or configuration of wires or supports, but other geometric shapes can also be used. The intermediate tubular layer 28 can extend substantially along the entire length of the sheath 22, or alternatively, only along a portion of the length of the sheath 22. Preferred wires may be circular, extending to a thickness of about 0.0005 inches to about 0.10 inches, or flat, extending to about 0.0005 inches × 0.003 inches to about 0.003 inches × 0.007 inches. However, other geometric shapes and sizes are also suitable for certain embodiments. When braided wire is used, the braiding density can be varied. Some embodiments have a braiding density of about 30 picks per inch to about 80 picks per inch and can contain up to 32 wires in various braiding patterns.

[0145] One representative embodiment of the intermediate tubular layer includes a braided nitinol composite material, at least partially encapsulated by an inner polymer tubular member and an outer polymer tubular member, respectively, arranged on the inner and outer surfaces of the intermediate tubular layer. Such encapsulation by the polymer layer can be achieved, for example, by fusing the polymer layer to the intermediate tubular layer or by dipping-coating the intermediate tubular layer. In some embodiments, the inner polymer tubular member, the intermediate tubular layer, and the outer polymer tubular layer can be arranged on a mandrel, and the layers can then be thermally fused or melted by placing the assembly in an oven or otherwise heating it. The mandrel can then be removed from the resulting sheath. In other embodiments, the inner polymer tubular member can be applied to the surface of the mandrel using dipping coating. The intermediate tubular layer can then be applied, and the inner polymer tubular member can be cured. The assembly can then be dipping-coated again, for example, to apply a thin coating of polyurethane, which will become the outer polymer tubular member of the sheath. The sheath can then be removed from the mandrel.

[0146] In addition, the intermediate tubular layer 28 can be braided or laser-cut to form a pattern or structure, for example, so that the intermediate tubular layer 28 is suitable for radial expansion. Figures 9 to 23 illustrate partial elevation views of various structures for the intermediate tubular layer. Some of the illustrated structures, such as those shown in Figures 11 to 14 and Figure 23, include at least one discontinuity. For example, the struts 56, 58, 60, 62, and 64 shown in Figures 11, 12, 3, 14, and 23 respectively result in a discontinuous intermediate tubular layer 28 in which the struts 56, 58, 60, 62, and 64 separate adjacent sections of the intermediate tubular layer 28 from each other, and the sections are separated from each other along a longitudinal axis parallel to the lumen of the sheath. Thus, the structure of the intermediate tubular layer 28 can vary from section to section and along the length of the sheath.

[0147] The structures shown in Figures 9 to 23 are not necessarily drawn to a fixed scale. The structural components and elements can be used individually or in combination within a single intermediate tubular layer 28. The extent of the intermediate tubular layer 28 is not intended to be limited to these specific structures, and they are merely illustrative examples.

[0148] Alternative embodiments of the sheath for introducing the prosthesis are also described. For example, Figures 24 to 26 illustrate cross-sectional and perspective views of a sheath 66 for introducing the prosthesis into the body, respectively. The sheath 66 comprises an inner layer, such as an inner polymer liner 68, an outer layer, such as an outer polymer tubular layer 70, and a hemostatic valve (not shown). The inner polymer liner 68 and the outer polymer tubular layer 70 at least partially enclose a lumen 72 through which the delivery device and prosthesis can pass from the outside of the patient's body into the patient's blood vessels. Either or both of the inner polymer liner 68 and the outer polymer layer 70 may be provided with at least one longitudinal notch and / or cut to facilitate radial expansion of the sheath.

[0149] For example, Figure 24 illustrates a longitudinal notch 74 in the inner polymer liner 68 that can facilitate the radial expansion of the sheath 66. The longitudinal notch 74 can be completely separated or ruptured when radial forces are applied due to the insertion of a delivery device or prosthesis. Similarly, Figure 25 illustrates a longitudinal cut 76 in the inner polymer liner 68 that can similarly facilitate the radial expansion of the sheath 66. The outer polymer layer 70 may, in addition or alternatively, have one or more longitudinal cuts 76 or notches 74. Such cuts and / or notches may extend substantially throughout the entire thickness of the layer, or only partially, whether they are located in the inner polymer liner 68 or the outer polymer layer 70. The cuts and / or notches may be located on or near the inner surface or outer surface of the inner and / or outer polymer layers 68, 70 or both.

[0150] Figure 26 illustrates a perspective view of one embodiment of an inner polymer liner 68 having longitudinal notches 74 and longitudinal cuts 76. More or fewer notches 74 and / or cuts 76 can be provided. For clarity, the outer polymer layer 70 is not shown in Figure 26. As shown in Figure 26, the longitudinal notches 74 and / or cuts 76 may extend only along a portion of the length of the sheath 66. In alternative embodiments, one or more notches 74 and / or cuts 76 may extend substantially along the entire length of the sheath 66. In addition, the notches 74 and / or cuts 76 may be randomly positioned or patterned.

[0151] One particular embodiment of the sheath 66 comprises a sheath having a notch or cut in the outer polymer layer 70 or the inner polymer layer (liner) 68 that extends longitudinally along about 75% of the length of the sheath 66. If such a notch or cut extends only partially through the relevant layer, it may have a relatively low tear force, such as about 0.5 pounds, so that the notch ruptures relatively easily during use.

[0152] The inner polymer liner 68 and the outer polymer layer 70 may optionally be bonded together or otherwise physically associated with each other. The amount of adhesion between the inner polymer liner 68 and the outer polymer layer 70 may be variable across the surface of the layers. For example, there may be little or no adhesion in areas around or near any notches and / or cuts present in the layers, so as not to hinder the radial expansion of the sheath 66. Interlayer adhesion may be produced, for example, by thermal bonding and / or coating. Embodiments of the sheath 66 can be formed from an extruded tube that can function as the inner polymer layer (liner) 68. The inner polymer layer (liner) 68 can be surface-treated by plasma etching, chemical etching, or other preferred methods of surface treatment. By treating the surface of the inner polymer liner 68, the outer surface of the inner polymer liner 68 may have areas with modified surface angles that can provide better adhesion between the inner polymer liner 68 and the outer polymer layer 70. The treated inner polymer liner can be immersion-coated, for example, with a polyurethane solution to form the outer polymer layer 70. In some configurations, polyurethane may not adhere well to the untreated surface area of ​​the inner polymer liner 68. Therefore, by surface-treating only the surface area of ​​the inner polymer liner 68 that is separated from the expansion area (e.g., the portion of the inner polymer liner 68 near the notches 74 and / or cutouts 76), the outer polymer layer 70 can be bonded to some areas of the inner polymer liner 68, while other areas of the inner polymer liner 68 remain free to slide against the outer polymer layer 70, thus allowing for expansion of the diameter of the sheath 66. Thus, areas around or near any notches 74 and / or cutouts 76 may experience little to no interlayer adhesion, while other areas of the inner and outer polymer layers 68, 70 may be bonded and fixed or otherwise physically linked to each other.

[0153] Similar to previously disclosed embodiments, the embodiments illustrated in Figures 24 to 26 may be applied to sheaths having a wide variety of inner and outer diameters. Applications may utilize sheaths of the present disclosure having an inner diameter of an inner polymer liner 68 that is expandable to an expanded diameter of about 3 Fr to about 26 Fr, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr. The expanded diameter may vary slightly along the length of the sheath 66. For example, the expanded outer diameter at the proximal end of the sheath 66 may range from about 3 Fr to about 28 Fr, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr, while the expanded outer diameter at the distal end of the sheath 66 may range from about 3 Fr to about 25 Fr, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr. The sheath 66 can be expanded to an expanded outer diameter that is approximately 10% larger than the original unexpanded outer diameter, up to approximately 100% larger than the original unexpanded outer diameter.

[0154] In some embodiments, the outer diameter of the sheath 66 gradually decreases from the proximal end to the distal end. For example, in one embodiment, the outer diameter may gradually decrease from about 26 Fr at the proximal end to about 18 Fr at the distal end. The diameter of the sheath 66 may transition gradually over substantially the entire length of the sheath 66. In other embodiments, the transition or reduction in the diameter of the sheath 66 may occur only along a portion of the length of the sheath 66. For example, the transition may occur along the length from the proximal end to the distal end, and the length may range from about 0.5 inches to almost the entire length of the sheath 66.

[0155] Suitable materials for the inner polymer liner 68 can include materials having high elastic strength, materials discussed in connection with other aspects, particularly Teflon (PTFE), polyethylene (e.g., high density polyethylene), fluoropolymers, or combinations thereof. In some aspects, the inner polymer liner 68 preferably has a low coefficient of friction, such as a coefficient of friction of from about 0.01 to about 0.5, including exemplary values of about 0.05, about 0.1, about 0.15, about 0.2, about 0.25, about 0.3, about 0.35, about 0.4, and about 0.45. In some further aspects of the sheath, 66 can comprise an inner polymer liner 68 having a coefficient of friction of about 0.1 or less, or 0.05 or less.

[0156] Similarly, suitable materials for the outer polymer layer 70 can include materials discussed in connection with other aspects and other thermoplastic elastomers and / or highly elastic materials.

[0157] The Shore hardness of the outer polymer layer 70 can be varied for different applications and aspects. Some aspects include an outer polymer layer having a Shore hardness of from about 25A to about 80A, including exemplary values of about 30A, about 35A, about 40A, about 45A, about 50A, about 55A, about 60A, about 65A, about 70A, and about 80A. Further, in other aspects, the outer polymer layer can have a Shore hardness of from about 20D to about 40D, including exemplary values of about 25D, about 30D, and about 35D. One aspect includes an easily available polyurethane having a Shore hardness of 72A. Another particular aspect comprises a polyethylene inner polymer layer dipped in polyurethane or silicone to create the outer polymer layer.

[0158] The sheath 66 can also include a radiopaque filler or marker as described above. In some aspects, distinct radiopaque markers or bands can be applied to certain portions of the sheath 66. For example, a radiopaque marker can be bonded to the inner polymer liner 68, the outer polymer layer 70, and / or positioned between the inner and outer polymer layers 68, 70.

[0159] Figures 27A to 27E and 28 illustrate cross-sectional views of various embodiments of the non-expandable (Figures 27A to 27E) and expandable (Figure 28) sheath 66 according to this disclosure. The sheath 66 includes a divided outer polymer tubular layer 70 having longitudinal notches 76 throughout the thickness of the outer polymer tubular layer 70 such that the outer polymer tubular layer 70 comprises a first portion 78 and a second portion 80 that are separable from each other along the notches 76. An expandable inner polymer liner 68 is associated with the inner surface 82 of the outer polymer tubular layer 70, and in the non-expandable configuration shown in Figure 27A, a portion of the inner polymer liner 68 extends through a gap created by the notches 76 and can be compressed between the first and second portions 78, 80 of the outer polymer tubular layer 70. As shown in Figure 28, when the sheath 66 is expanded, the first and second portions 78, 80 of the outer polymer tubular layer 70 are separated from each other, and the inner polymer liner 68 is expanded into a substantially cylindrical tube. In some embodiments, two or more longitudinal cuts 76 may be provided through the thickness of the outer polymer tubular layer 70. In such embodiments, a portion of the inner polymer liner 68 may extend through each of the longitudinal cuts 76 provided within the outer polymer tubular layer 70.

[0160] In certain embodiments, the inner polymer liner 68 comprises one or more materials that are elastic and suitable for folding and / or pleating. For example, Figure 27A illustrates an inner polymer liner 68 having a folded region 85. As seen in Figures 27A to 27E, the sheath 66 may be provided with one or more folded regions 85. Such folded regions 85 may be provided radially and substantially coincide with the circumference of the outer polymer tubular layer 70. At least a portion of the folded region 85 may be positioned adjacent to the outer surface 83 of the outer polymer tubular layer 70.

[0161] In addition, as shown in Figures 27B and 27E, at least a portion of the folded region 85 may be overlapped by an outer cover, such as an outer polymer cover 81. In such embodiments, the outer polymer cover 81 may be an elongated tube as disclosed herein. The outer polymer cover 81 may be adjacent to at least a portion of the outer surface 83 of the outer polymer tubular layer 70. The outer polymer cover 81 serves to at least partially encompass the folded region 85 of the inner polymer liner 68 and can also prevent the folded region 85 from separating from the outer polymer tubular layer 70, for example, when the sheath 66 is bent. In some embodiments, the outer polymer cover (or elongated tube as described herein) 81 may be at least partially bonded to the outer surface 83 of the outer polymer tubular layer 70. In certain embodiments, the outer polymer cover (elongated tube) 81 may increase the rigidity and / or durability of the sheath 66, while in other embodiments, as also disclosed herein, it may reduce the pressing force required to press the medical device through the sheath. However, in certain embodiments, as shown in Figures 27B and 27E, the outer polymer cover 81 may not completely overlap the circumference of the sheath 66. For example, the outer polymer cover 81 may have first and second ends that do not come into contact with each other. In these embodiments, only a portion of the folded area 85 of the inner polymer liner 68 is overlapped by the outer polymer cover 81.

[0162] In embodiments having multiple folded regions 85, the regions may be displaced equally from each other around the circumference of the outer polymer tubular layer 70. Alternatively, the folded regions may be off-center, of different sizes, and / or randomly separated from each other. The portions of the inner polymer liner 68 and the outer polymer tubular layer 70 may be bonded to each other or otherwise bonded, but the folded regions 85 are preferably not bonded to or bonded to the outer polymer tubular layer 70. For example, the bond between the inner polymer liner 68 and the outer polymer tubular layer 70 may be best within a region of minimal expansion.

[0163] One particular embodiment of the sheath, as illustrated in Figures 27A to 28, comprises a polyethylene (e.g., high-density polyethylene) outer polymer tubular layer 70 and a PTFE inner polymer liner 68. However, as described above, other materials are suitable for each layer. Generally, suitable materials for use with the outer polymer tubular layer 70 include materials having a high stiffness or strength coefficient that can support the expansion and contraction of the inner polymer liner 68.

[0164] In certain embodiments, the inner liner 68 comprises one or more folded portions, the inner liner can be selectively etched as disclosed above. In such embodiments, at least a portion of the outer surface of at least one folded portion of the inner liner is not etched along at least a portion of the sheath length. In even further embodiments, the outer surface of the inner liner comprises one or more unetched portions along the sheath length. Again, in embodiments where there are multiple unetched portions, such portions can be at any position on the sheath. In certain embodiments, for example, but not limited to, each of the one or more unetched portions is followed by an etched portion. On the other hand, in other embodiments, the one or more unetched portions include the outer surface of at least one folded portion.

[0165] In certain embodiments, the sheaths disclosed herein may exhibit insertion forces of less than about 60 N, less than about 50 N, less than about 40 N, or less than about 30 N. In further embodiments, the sheaths may exhibit an insertion force reduction of at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or at least about 100% compared to a substantially identical reference sheath without the first composite composition and selectively etched inner liner.

[0166] In a further embodiment, the sheath comprises an inner liner which is selectively etched and has an unetched portion as disclosed above, such a sheath may even exhibit a substantial reduction in insertion force compared to a substantially identical sheath without a similar unetched portion.

[0167] In some embodiments, the outer polymer tubular layer 70 comprises the same material or combination of materials along its entire length. In alternative embodiments, the material composition may vary along the length of the outer polymer tubular layer 70. For example, the outer polymer tubular layer may be provided with one or more segments, and the composition may vary by segment. In one particular embodiment, the durometer grade of the composition varies along the length of the outer polymer tubular layer 70 such that the segment near the proximal end comprises a stiffer material or combination of materials, while the segment near the distal end comprises a softer material or combination of materials. This may allow for a sheath 66 that has a relatively stiff proximal end at the point of introduction of the delivery device, while still having a relatively soft distal end at the point of entry into the patient's blood vessel.

[0168] As with other disclosed embodiments, embodiments of the sheath 66 shown in Figures 27A–28 may be available in a wide range of sizes and dimensions. For example, the sheath 66 may be offered with non-expanding bore diameters from about 3 Fr to about 26 Fr, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr. In some embodiments, the sheath 66 has a non-expanding bore diameter of about 15 Fr to about 16 Fr. In some embodiments, the unexpanded inner diameter of the sheath 66 may range from about 3 Fr to about 28 Fr at or near the distal end of the sheath 66, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr, while the unexpanded inner diameter of the sheath 66 may range from about 3 Fr to about 26 Fr at or near the proximal end of the sheath 66, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr. For example, in one unexpanded embodiment, the sheath 66 can transition from an unexpanded inner diameter of about 16 Fr at or near the distal end of the sheath 66 to an unexpanded inner diameter of about 26 Fr at or near the proximal end of the sheath 66.

[0169] The sheath 66 may be provided with an unexpanded outer diameter of about 3 Fr to about 30 Fr, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr, and in some embodiments, it may have an unexpanded outer diameter of about 18 Fr to about 19 Fr. In some embodiments, the unexpanded outer diameter of the sheath 66 may range from about 3 Fr to about 28 Fr at or near the distal end of the sheath 66, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr, while the unexpanded outer diameter of the sheath 66 may range from about 3 Fr to about 30 Fr at or near the proximal end of the sheath 66, including exemplary values ​​of about 5 Fr, about 10 Fr, about 15 Fr, about 20 Fr, and about 25 Fr. For example, in one non-expanded configuration, the sheath 66 can transition from a non-expanded outer diameter of approximately 18 Fr at or near the distal end of the sheath 66 to a non-expanded outer diameter of approximately 28 Fr at or near the proximal end of the sheath 66.

[0170] The thickness of the inner polymer liner 68 may vary, but in some preferred embodiments it is approximately 0.002 inches to approximately 0.015 inches, including exemplary values ​​of approximately 0.003 inches, approximately 0.004 inches, approximately 0.005 inches, approximately 0.006 inches, approximately 0.007 inches, approximately 0.008 inches, approximately 0.009 inches, approximately 0.010 inches, approximately 0.011 inches, approximately 0.012 inches, approximately 0.013 inches, and approximately 0.014 inches. In some embodiments, the expansion of the sheath 66 may result in an expansion of the non-expanded outer diameter of approximately 10% or less to approximately 430% or more, for example, but not limited to, approximately 1%, 5%, 10%, 20%, 50%, 70%, 100%, 120%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, or even more.

[0171] As with other illustrated and described embodiments, the embodiments shown in Figures 27A to 28 may provide a radiopaque filler and / or a radiopaque tip marker as described above. The sheath 66 may provide a radiopaque tip marker provided at or near the distal end of the sheath 66. Such a radiopaque tip marker may include materials suitable for radiopaque fillers, such as platinum, iridium, platinum / iridium alloys, stainless steel, other biocompatible metals, or combinations thereof.

[0172] In a further embodiment in which folded portions may exist, at least one folded portion may comprise a first folded edge and a second folded edge, and an overlapping portion extending circumferentially between the first and second folded edges, the overlapping portion comprising a radial overlap of at least two thicknesses of the inner liner, the first folded edge being configured to move closer to the second folded edge during the application of radially outward forces due to the passage of a medical device, thereby shortening the overlapping portion at a local axial location, the shortening of the overlapping portion corresponding to a local expansion of the lumen. Furthermore, in other embodiments, at least one folded portion comprises a first folded edge and a second folded edge, and an overlapping portion extending circumferentially between the first and second folded edges, the overlapping portion comprising a radial overlap of at least two thicknesses of the inner liner, the first folded edge being configured to move closer to the second folded edge during the application of radially outward forces due to the passage of a medical device, thereby shortening the overlapping portion at a local axial location, the shortening of the overlapping portion corresponding to a local expansion of the lumen, the outer layer comprising a first longitudinally extending edge and a second longitudinally extending edge configured to separate as the sheath expands, the first longitudinally extending edge and the overlapping portion of the outer layer extending over the second longitudinally extending edge when the sheath is not expanded.

[0173] In further embodiments, it is understood that the inner liner may be configured to expand into a substantially cylindrical tube.

[0174] In further embodiments, a sheath comprising an elongated tube as disclosed and described herein may further comprise an inner tubular layer having a longitudinal slit and partially defining an inner lumen, and a first outer tubular layer enclosing the inner layer, the outer tubular layer comprising a longitudinally extending folded flap that covers a portion of the outer surface of the outer layer when the sheath is in a non-expanded state, and the elongated tube is positioned such that the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer.

[0175] Such exemplary embodiments are described in detail below. Figures 50 and 51 show cross-sectional views of an expandable sheath 166 having an inner tubular layer 168 with a longitudinal slit 169. In some embodiments, the longitudinal slit 169 extends along the entire length of the inner tubular layer 168. A first outer tubular layer 170 encloses the inner tubular layer 168 and includes a longitudinally extending folded flap 171. In some embodiments, the folded flap 171 extends along the entire length of the first outer tubular layer 170. The folded flap 171 covers a portion of the outer surface 183 of the first outer tubular layer 170 when the sheath is in an unexpanded state (Figure 50). As the prosthesis is moved through the inner lumen 172 of the sheath 166, an outwardly directed force is applied to the inner tubular layer 168, expanding the longitudinal slit 169 and unfolding the folded flap 171. Figure 51 shows the sheath 166 in its non-expanded state, with the longitudinal slit 169 expanded and the first outer tubular layer 170 widened.

[0176] The folded flap 171 of the first outer tubular layer 170 has a base 173. The base 173 may be positioned radially outward from the longitudinal slit 169. In some embodiments, the base 173 is centered across the longitudinal slit 169. The folded flap 171 further includes a longitudinally extending overlay portion 175 that extends from the base 173 to a longitudinally extending fold 179 at the edge of the flap 171. The longitudinally extending overlay portion 175 covers a longitudinally extending lower portion 177 and is separated from the lower portion 177 by the fold 179. The lower portion 177 contacts the outer surface 183 of the first outer tubular layer 170 when the sheath is in an unexpanded state, as shown in Figure 50.

[0177] Some embodiments of the sheath 166 can include a plurality of longitudinally extending folded flaps that cover portions of the outer surface 183 of the first outer tubular layer 170 positioned at various locations around the circumference of the sheath 166. For example, 2, 3, 4, 5, 6, 7, 8, 9, or 10 longitudinally extending folded flaps can be positioned around the circumference. In some embodiments, these plurality of folded flaps are evenly spaced around the circumference of the sheath 166.

[0178] The folded flap 171 extends circumferentially around a portion of the circumference of the sheath 166. In some embodiments, the longitudinally extending flap 171 extends around about 20% to about 40% (including about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, and about 40% of the outer circumference of the first outer tubular layer 170) when the sheath 166 is not expanded. In one example, for a sheath having a non-expanded outer diameter of 14F (4.7 millimeters), the folded flap extends around about 85 to about 120 degrees (including exemplary values of about 90, about 95, about 100, about 105, about 110, and 115 degrees), or about 23% to 35% (including exemplary values of about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%) of the circumference, resulting in an inner lumen having an expanded diameter of about 7.6 millimeters to about 8.4 millimeters (including exemplary values of about 7.7mm, about 7.8nm, about 7.9mm, about 8.0mm, about 8.1mm, about 8.2mm, and about 8.3mm) that can be used with a valve having a crimped outer diameter of 6.4 millimeters and an expanded outer diameter of 26 millimeters.

[0179] In Figure 51, the wall thickness of the flap 171 is labeled t, and the wall thickness of the rest of the first outer tubular layer 170 is labeled T. In some embodiments, a portion of the flap 171 (e.g., the lower portion 177 or the superposition portion 175) may have a wall thickness t that is thinner than the wall thickness (T) of the rest of the outer tubular layer. This variation in wall thickness promotes uniform column strength around the circumference of the sheath 166, which reduces torsion and minimizes the overall outer diameter of the sheath. The variation in wall thickness can also facilitate the folding process. In some embodiments, the entire flap 171 has a wall thickness t that is thinner than the wall thickness T of the rest of the outer tubular layer. In one embodiment, the wall thickness t may range from about 0.003 inches to about 0.007 inches, including exemplary values ​​of about 0.004 inches, about 0.005 inches, and about 0.006 inches, while the wall thickness T may range from about 0.008 inches to about 0.012 inches, including exemplary values ​​of about 0.009 inches and about 0.01 inches. In other embodiments, such as those shown in Figure 51, the wall thickness t of the flap 171 is approximately equal to the wall thickness T of the rest of the first outer tubular layer 170.

[0180] The first outer tubular layer 170 is formed from a material having a low coefficient of friction, a high coefficient of tensile strength, and a high maximum tensile strength in order to improve the transmission of pressing force through the length of the sheath 166 while reducing torsion. Good transmission of pressing force means that the force applied by the operator to advance the sheath is predictable, responsive, and consistent along the length of the sheath. However, an excessively high coefficient of tensile strength may limit the ability of the longitudinally extending flap 171 to open, which may hinder the transmission of pressing force. A desirable range for the tensile modulus of the first outer tubular layer 170 is about 300 MPa to about 2,000 MPa (including about 300 MPa, about 400 MPa, about 500 MPa, about 600 MPa, about 700 MPa, about 800 MPa, about 900 MPa, about 1000 MPa, about 1100 MPa, about 1200 MPa, about 1300 MPa, about 1400 MPa, about 1500 MPa, about 1600 MPa, about 1700 MPa, about 1800 MPa, about 1900 MPa, and 2000 MPa). In some embodiments, the tensile modulus is preferably at least 700 MPa. High axial and radial stiffness may allow the sheath to be easily inserted and to resist crushing within the body.

[0181] The maximum tensile strength of the first outer tubular layer 170 can be at least 50 MPa. A high maximum tensile strength helps prevent the material from tearing as the prosthesis advances through the sheath.

[0182] In some exemplary and non-limiting embodiments, the first outer tubular layer 170 in the embodiments shown in Figures 50 and 51 may include high-density polyethylene (HDPE), polyamide, copolyamide, polyether block amide (PEBAX®), or a blend of polyamides. Since the first outer tubular layer 170 may be biased toward a folded state (e.g., by thermal solidification), a material with shape memory properties is advantageous. This facilitates the refolding of the first outer tubular layer 170 after passing through the prosthesis. PEBAX® is an exemplary shape memory material that can be thermally solidified toward a folded state.

[0183] In some embodiments, the outer surface 183 of the first outer tubular layer 170 may include a hydrophilic coating. In some embodiments, a joint can be created between the lower portion 177 of the folded flap 171 and the outer surface 183 of the first outer tubular layer 170. The joint may be a thermal joint (where a portion of the contact layers are melted together) or a separate layer of adhesive.

[0184] As discussed above, the inner tubular layer 168 in the embodiments shown in Figures 50 and 51 includes a longitudinal slit 169. The inner tubular layer 168 may have a first longitudinally extending end 178 and a second longitudinally extending end 180, the first and second longitudinally extending ends 178 and 180 defining a longitudinal slit 171.

[0185] The inner tubular layer 168 forms a low-friction barrier between the passing prosthesis and the first, higher-friction outer tubular layer 170. The inner tubular layer 168 extends around at least 80% (or at least 85%, or at least 90%, or at least 95%) of the circumference of the inner lumen 172 when the sheath 166 is in a non-expanded state. This advanced covering limits contact between the passing prosthesis and the first, higher-friction outer tubular layer 170. In some embodiments, the coefficient of friction (static or dynamic) of the inner tubular layer 168 according to ASTM D1894 is 0.30 or less, or 0.25 or less, or 0.20 or less, or 0.1 or less, or 0.05 or less. In other embodiments, the coefficient of friction is 0.25 or less.

[0186] In some embodiments, the low-friction inner tubular layer 168 comprises or is formed from a material having a tension coefficient of at least about 300 MPa (and up to about 1,400 MPa, including exemplary values ​​of about 350 MPa, about 400 MPa, about 450 MPa, about 500 MPa, about 550 MPa, about 600 MPa, about 650 MPa, about 700 MPa, about 750 MPa, about 800 MPa, about 850 MPa, about 900 MPa, about 1,000 MPa, about 1,050 MPa, about 1,100 MPa, about 1,150 MPa, about 1,200 MPa, about 1,250 MPa, about 1,300 MPa, and about 1,350 MPa) in order to provide good transmission of compressive force while providing torsional resistance. This material may be, for example, high-density polyethylene or a fluoropolymer. Exemplary fluoropolymers include polytetrafluoroethylene, ethylenefluorinated ethylenepropylene, or perfluoroalkoxy.

[0187] The tie layer 174 is positioned between the two layers, thereby allowing the inner tubular layer 168 to be bonded to the first outer tubular layer 170. In some embodiments, the tie layer 174 may be formed from polyurethane or functionalized polyolefin. In some embodiments, the contact surface of the inner tubular layer 168 can be etched to improve bonding to the tie layer. For example, the inner tubular layer 168 containing or formed from a fluoropolymer can be etched on its outer surface to improve thermal bonding to the tie layer 174. In further embodiments, the inner tubular layer 168 can be selectively etched as described above.

[0188] As shown in Figure 52, the sheath comprises an elongated tube, as disclosed herein in detail, forming a second outer layer 181. In such embodiments, the elongated tube forms a second outer layer having an inner and outer surface, the elongated tube is located at least at the proximal end of the sheath, and extends along at least a portion of the length of the sheath such that the inner surface of the elongated tube covers at least a portion of the outer surface of the first outer tubular layer. This second outer layer is understood to be also referred to as an outer jacket in some embodiments. The outer jacket 181 may be formed as disclosed herein and comprise a first polymer layer, the first polymer layer comprising a first composite composition comprising a polymer including more than 0% to 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of an inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of a solid lubricating filler based on the total weight of the first composite composition. Additional exemplary embodiments of the composition and properties of such a second outer layer (outer jacket) are disclosed in detail above.

[0189] As described above, in some embodiments, the first outer tubular layer 170 may include or be formed from a shape memory material (e.g., a thermosetting polymer such as PEBAX®) that facilitates the refolding of the first outer tubular layer 170 after expansion. In embodiments disclosed herein, a second outer layer (outer jacket) 181 may extend over and enclose the first outer tubular layer 170. The refolding of the first outer tubular layer 170 may preferably return the sheath 166 to its original outer diameter or a value close to its original outer diameter (e.g., within about 10%, 20%, 30%, 40%, or 50% of the original outer diameter).

[0190] The method of using the sheaths shown in Figures 50-52 involves first inserting the expandable sheath 166 into the target vascular system and advancing the prosthesis through the inner lumen 172 of the expandable sheath 166. The prosthesis applies an outward-directed radial force to the inner tubular layer 168 of the expandable sheath 166. In some embodiments, the outward-directed radial force is transmitted through the inner tubular layer 168, the tie layer 174, and the first outer tubular layer 170. The outward-directed radial force expands the longitudinal slit 169 of the inner tubular layer 168. In some embodiments, the expansion of the longitudinal slit 169 extends over the entire length of the expandable sheath.

[0191] An outward-directed radial force further expands the expandable sheath by spreading the longitudinally extending flap 171 of the first outer tubular layer 170. The spreading of the flap 171 may include sliding the longitudinally extending overlay portion 175 circumferentially against the longitudinally extending lower portion 177 of the flap 171. The lower portion 177 can slide circumferentially against the outer surface 183 of the first outer tubular layer 170. In some embodiments, the spreading of the longitudinally extending flap 171 occurs at a position radially outward from the longitudinal slit 169 of the inner tubular layer 168. In some embodiments, the spreading of the flap 171 may extend along the entire length of the expandable sheath 166.

[0192] The longitudinal slit 169 in the inner tubular layer 168 narrows when the outward-directed radial force ceases (i.e., when the prosthesis passes through). The slit 169 may narrow back to its original width or a value close to its original width (for example, within 10% of its original width). Narrowing may occur along the entire length of the sheath 166. The prosthesis is then delivered to the procedure site.

[0193] The longitudinally extending flap 171 folds back, at least partially, when the prosthesis stops applying an outwardly directed radial force (i.e., when it passes through). In some embodiments, the longitudinally extending flap 171 folds back due to a shape memory bias toward the folded state. In some embodiments, an inwardly directed radial force is applied to the outer surface 183 of the first outer tubular layer 170, causing the longitudinally extending flap 171 to fold back (e.g., by the second outer layer (outer jacket) 181).

[0194] Examples of methods for fabricating a sheath are as follows. These steps are not intended to be limiting. The listed steps can be rearranged as needed. Other steps can be added, or some steps may not be necessary in other embodiments. Sizes are approximate. This specification discloses exemplary embodiments of fabricating a sheath in which an elongated tube or a recoverable outer jacket covers the entire length of an expandable sheath shaft assembly. In particular embodiments, the elongated tube and expandable sheath shaft assembly may be about 380 mm (15 inches) in length. 1) Starting with a PTFE inner layer with an inner diameter (ID) of approximately 0.200 inches and a wall thickness of approximately 0.004 inches, 2) loading the PTFE inner layer onto a tapered mandrel of approximately 0.200 inches to approximately 0.187 inches, 3) stretching it onto a mandrel section with an outer diameter (OD) of 0.187 inches under heat, 4) expanding the proximal end of the PTFE from 0.200 inches ID to 0.340 inches ID under heat, and 5) expanding it with air pressure, thereby creating a Tecoflex with an ID of approximately 0.200 inches and a wall thickness of approximately 0.004 inches across the PTFE inner layer along the main body section. Load a tie layer such as 80A, 6) coat it with, for example, FEP (fluorinated ethylene propylene) heat shrink tubing and apply heat to bond the tie layer to the inner layer, 7) remove the FEP heat shrink tubing if used, 8) create a longitudinal slit along the main body section of the assembly, 9) load the subassembly with the slit onto a 0.187 inch OD mandrel, 10) load the outer layer across the body, 11) fold the outer layer, 12) insert the subassembly with the fold inside, for example, heat shrink tubing and heat-solidify the fold by placing the assembly in an oven, 13) remove the shrink tubing if used, 14) add a second outer layer, and 14) remove the sheath from the mandrel.

[0195] The outer jacket can be expanded to a larger diameter by applying air pressure to the inner diameter of the outer jacket. The assembled sheath can then be inserted into the expanded outer jacket over the desired length. The air pressure can then be released to allow the outer jacket to reduce its diameter back to its original diameter.

[0196] Also disclosed are exemplary embodiments of fabricating a sheath in which an elongated tube or a retrievable outer jacket covers the proximal side of an expandable sheath shaft assembly. In such exemplary embodiments, a sheath shaft having a length of about 380 mm (15 inches) can be assembled. For example, a tapered mandrel can be inserted into the inner diameter of the sheath shaft assembly. The outer jacket or strain relief tube can be cut to about 105 mm ± 10 mm (4.15 inches ± 0.40 inches) as disclosed herein and positioned on the sheath shaft assembly. The outer jacket, in particular, if the outer jacket consists of a low-friction PTFE embedded layer, can have an inner diameter large enough to allow the outer jacket to slide across the sheath shaft assembly. The FEP (fluoroethylene propylene) heat shrink tubing can then be wide-mouthed at the proximal end. The wide-mouthed FEP heat shrink tubing can be slid across the outer jacket. Heat can be used to fuse the outer jacket to the sheath shaft assembly. The distal end of the outer jacket can be heated to bond it to the sheath shaft assembly. The FEP heat shrink tubing can then be removed.

[0197] Furthermore, the mandrel can be removed. Even further, the proximal end of the sheath and the outer jacket assembly can be wide-mouthed on a heated wide-mouth machining tool. It is understood that in some exemplary and non-limiting embodiments, other manufacturing steps may be present, such as joining the flushing tube and housing, hydrophilic coating, inspection, valve and sleeve assembly, and leak testing.

[0198] Figures 29A to 29D show cross-sectional views of other possible configurations of the sheath 66 for introducing an orthotic device into a patient's vascular system. The sheath 66 comprises a polymer tubular layer 84 having an inner surface 86 and an outer surface 88. The thickness of the polymer tubular layer 84 extends from the inner surface 86 to the outer surface 88. As shown in Figures 29B to 29D, the polymer tubular layer 84 may be formed with a first angled portion 90 of reduced thickness adjacent to at least the inner surface 86 and a second angled portion 92 of reduced thickness adjacent to the outer surface 88, the second portion 92 at least partially overlapping the first portion 90. Figure 29A illustrates a similar configuration in which the second portion 92 at least partially overlaps the first portion 90 in a partial coil configuration. In the embodiment of Figure 29A, the second portion 92 and the first portion 90 may have the same thickness.

[0199] In a preferred embodiment, the first portion 90 and the second portion 92 are not bonded to each other. In some embodiments, a small gap 94 may exist between the first and second portions 90, 92, which can give the sheath 66 the appearance of having two internal lumens 72, 94, as is best seen in Figure 29A. Figures 29A to 29D illustrate the sheath 66 in a non-expandable configuration. When the sheath 66 is expanded, the ends of the first and second portions 90, 92 are in contact with each other or close together to reduce or eliminate any gap between them.

[0200] In some embodiments, the sheath 66 may have a partial slit or notch along at least a portion of its length. For example, as shown in Figure 33, the sheath 66 may have an outer polymer tubular layer 70 extending over an inner polymer liner 68. The inner polymer layer may extend through a notch in the outer polymer tubular layer 70, as also shown in Figure 27C, to form a folded region 85 on the outer surface of the outer polymer tubular layer 70. In some embodiments, the folded region 85 of the inner layer terminates in front of the outer polymer tubular layer 70 (i.e., the outer polymer tubular layer 70 is longer than the inner layer). In these embodiments, as shown in Figure 33, the sheath 66 may have a partial slit or notch 77 that may extend from the end (distal end) 75 of the folded region 85 to the distal end 40 of the sheath 66. In some embodiments, the notch 77 may facilitate the expansion of the sheath 66.

[0201] The notch line 77 can be substantially centered relative to the folded region 85. In an alternative embodiment, the notch line 77 can be located elsewhere relative to the folded region 85. The sheath 66 may also have one or more notches 77. For example, as shown in Figure 34, one or more notches 77 can be located peripherally relative to the folded region 85. One or more notches 77 can be located anywhere around the circumference of the outer polymer tubular layer 70. In an embodiment with a radiopaque marker 69, as seen in Figure 33, the notch line 77 can extend, for example, from the distal end of the radiopaque marker 69 substantially to the distal end 40 of the sheath 66.

[0202] Figures 35 and 36 illustrate an expandable sheath 100 according to this disclosure, which may be used with a delivery device for delivering prostheses such as tissue heart valves into a patient. Generally, the delivery device may include a movable guide catheter (also referred to as a flex catheter) (as depicted, for example, in Figure 1), a balloon catheter extending through the guide catheter, and a nasal catheter extending through the balloon catheter. However, it should be understood that sheath 100 may refer to any type of sheath disclosed herein and which may be used with a delivery device. The specific configuration of sheath 100 is not limited to one specific description and may include any configuration disclosed herein. The guide catheter, balloon catheter, and nasal catheter may be fitted to slide longitudinally relative to each other to facilitate the delivery and positioning of the valve at the implantation site in the patient's body. However, it should be noted that sheath 100 may be used with any type of elongated delivery device used for implanting balloon-expandable prostheses, self-expanding prostheses, and other prostheses. Generally, the sheath 100 can be inserted into a blood vessel (e.g., a femoral artery or iliac artery) by passing through the patient's skin, such that a soft tip portion 102 at the distal end 104 of the sheath 100 is inserted into the blood vessel. The sheath 100 may also include a proximal wide-mouth portion 114 to facilitate engagement with the introducer housing 101 and the catheter described above (for example, the proximal wide-mouth portion 114 may provide a compression fit across the housing tip, and / or the proximal wide-mouth portion 114 may be secured to the housing 101 via a nut or other fastening device, or by joining the proximal end of the sheath to the housing). The introducer housing 101 may house one or more valves that, when inserted through the housing, form a seal around the outer surface of the delivery device, as is known in the art. The delivery device may be inserted into and through the sheath 100, allowing the prosthesis to be advanced through the patient's vascular system and implanted in the patient.

[0203] In certain embodiments, the sheath 100 may include multiple layers. For example, the sheath 100 may include an inner layer 108 and an outer layer 110 positioned around the inner layer 108. The inner layer 108 may define a lumen through which a delivery device can advance into the patient's blood vessels in order to deliver, remove, repair, and / or replace an ossotomy that moves along the longitudinal axis X. As the ossotomy passes through the sheath 100, the sheath locally expands from a first stationary diameter to a second expanded diameter to accommodate the ossotomy. After the ossotomy has passed through a particular location in the sheath 100, each continuous expanded portion or segment of the sheath 100 returns at least partially to a smaller stationary diameter. In this way, the sheath 100 may be considered self-expanding in that it does not require the use of balloons, dilators, and / or occlusion devices for expansion.

[0204] The inner and outer layers 108, 110 may include any suitable material. Suitable materials for the inner layer 108 include polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), nylon, polyethylene, polyether block amide (e.g., PEBAX®), and / or combinations thereof. In one specific embodiment, the inner layer 108 may include a lubricating, low-friction, or hydrophilic material such as PTFE. Such low-friction materials can facilitate the passage of the prosthesis through the lumen defined by the inner layer 108. In some embodiments, the inner layer 108 may have a coefficient of friction of less than about 0.1. Some embodiments of the sheath 100 may include a lubricating liner on the inner surface of the inner layer 108. Suitable lubricating liners include materials that can further reduce the coefficient of friction of the inner layer 108, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for the lubricating liner may also include other materials having a coefficient of friction of preferably 0.1 or less.

[0205] Suitable materials for the outer layer 110 include nylon, polyethylene, PEBAX®, HDPE, polyurethane (e.g., Tecoflex®), and other medical-grade materials. In one embodiment, the outer layer 110 may include extruded high-density polyethylene (HDPE) and Tecoflex® (or other polyurethane material) as a composite material. In some embodiments, Tecoflex® may act as an adhesive between the inner layer 108 and the outer layer 110 and may be present only along a portion of the inner surface of the outer layer 110. Other suitable materials for the inner and outer layers are also disclosed in U.S. Patent Application Publication No. 2010 / 0094392, which is incorporated herein by reference.

[0206] In addition, several embodiments of the sheath 100 may include an external hydrophilic coating on the outer surface of the outer layer 110. Such a hydrophilic coating can facilitate the insertion of the sheath 100 into the patient's blood vessels. Examples of suitable hydrophilic coatings include Harmony® Advanced Lubricity Coating and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM Medical Coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride) are also suitable for use with the sheath 100. An elongated tube, which functions as an outer jacket, can then be placed on the outer layer of the sheath.

[0207] As best illustrated in Figure 36, the flexible tip portion 102 may, in some embodiments, include low-density polyethylene (LDPE) and may be configured to minimize trauma or damage to the patient's blood vessels as the sheath is navigated through the vascular system. For example, in some embodiments, the flexible tip portion 102 may be slightly tapered to facilitate passage through the blood vessels. The flexible tip portion 102 may be fixed to the distal end 104 of the sheath 100, for example, by thermally bonding the flexible tip portion 102 to the inner and outer layers of the sheath 100. Such a flexible tip portion 102 may provide a lower hardness than the rest of the sheath 100. In some embodiments, the flexible tip 102 may have a Shore hardness of about 25D to about 40D. The tip portion 102 is radially expandable and configured to allow the prosthesis to pass through the distal opening of the sheath 100. For example, the tip portion 102 may be formed with weakened portions such as axially extending notches or perforations, which are divided (as shown in the embodiments of Figures 33 and 34) and configured to allow the tip portion to expand radially as the prosthesis passes over it.

[0208] Figure 37 shows a cross-sectional view of the sheath 100 obtained near the distal end 104 of the sheath 100. As shown in Figures 36 and 37, the sheath 100 may include at least one radiopaque filler or marker, such as a discontinuous or C-shaped band 112, located near the distal end 104 of the sheath 100. The marker 112 may be associated with the inner and / or outer layers 108, 110 of the sheath 100. For example, as shown in Figure 37, the marker 112 may be located between the inner layer 108 and the outer layer 110. In an alternative embodiment, the marker 112 may be associated with the outer surface of the outer layer 110. In some embodiments, the marker 112 may be embedded in or blended into the inner layer 108 or the outer layer 110.

[0209] The C-shaped band 112 can function as a radiopaque marker or filler to allow visibility of the sheath 100 under fluoroscopy during in-patient use. The C-shaped band 112 may include any suitable radiopaque material such as barium sulfite, bismuth trioxide, titanium dioxide, bismuth subcarbonate, platinum, iridium, and combinations thereof. In one specific embodiment, the C-shaped band may contain 90% platinum and 10% iridium. In other embodiments, the marker 112 does not have to be a C-shaped band; other shapes, designs, and configurations are possible. For example, in some embodiments, the marker 112 may extend around the entire circumference of the sheath 100. In other embodiments, the marker 112 may include a number of smaller markers spaced apart around the sheath 100.

[0210] Figures 38 and 39 show additional cross-sectional views obtained at different points along the sheath 100. Figure 38 shows a cross-section of a segment of the sheath near the proximal end 106 of the sheath 100, as indicated by lines 38-38 in Figure 35. At this location, the sheath 100 may include an inner layer (or liner) 108 and an outer layer 110. At this location near the proximal end of the sheath, the layers 108, 110 may be substantially tubular, with no slits or folded portions within the layers. In contrast, the layers 108, 110 at different locations along the sheath 100 (e.g., at the points indicated by lines 39-39 in Figure 35) may have different configurations.

[0211] As shown in Figure 39, the inner layer (inner liner) 108 may be arranged to form a substantially cylindrical lumen 116 through it. The inner liner 108 may include one or more folded portions 118. In the embodiment shown in Figure 39, the inner liner 108 is arranged to have one folded portion 118 which may be located on both sides of the inner layer (inner liner) 108. The folded portion 118 includes a first fold (e.g., a longitudinally extending fold line) and a second fold, and an overlapping portion extending circumferentially between them (when the sheath is in a non-expandable configuration). As shown in Figure 39, the folded portion 118 includes a radial overlap of at least two thicknesses of the inner layer 108. The inner layer 108 may be continuous in that there are no tears, slits, or perforations in the inner layer 108. The outer layer 110 may be arranged in an overlapping manner such that the overlapping portion 120 overlaps with at least a portion of the folded portion 118 of the inner layer 108. As shown in Figure 39, the overlapping portion 120 also overlaps with the lower portion 122 of the outer layer 110. The lower portion 122 may be positioned below both the overlapping portion 120 of the outer layer 110 and the folded portion 118 of the inner layer 108. Thus, the outer layer 110 may be discontinuous in that it includes slits or cuts to form the overlapping and lower portions 120, 122. In other words, the first edge 124 of the outer layer 110 is separated from the second edge 126 of the outer layer 110 so as not to form a continuous layer.

[0212] As shown in Figure 39, the sheath 100 may also include a thin layer of bonding or adhesive material 128, also referred to as a tie layer, positioned between the inner and outer layers 108, 110. In one embodiment, the adhesive material 128 may include a polyurethane material such as Tecoflex® or an etched PTFE tube. The adhesive material 128 may be positioned on at least a portion of the inner surface 130 of the outer layer 110 to provide adhesion between selected portions of the inner and outer layers 108, 110. For example, the outer layer 110 may include only the adhesive layer 128 around a portion of the inner surface 130 facing the lumen-forming portion of the inner layer 108. In other embodiments, the adhesive layer 128 may be positioned so as not to contact the folded portion 118 of the inner layer 108. In other embodiments, the adhesive layer 128 may be positioned in different configurations as desired for a particular application. For example, as shown in Figure 39, the adhesive layer 128 may be positioned along the entire inner surface 130 of the outer layer 110. In an alternative embodiment, the adhesive layer may be applied to the outer surface of the inner liner 108 instead of the inner surface of the outer layer. The adhesive layer 128 may be applied to all or selected portions of the inner layer 108. For example, the adhesive layer 128 may be formed only on a portion of the inner layer facing the lumen-forming portion of the outer layer, rather than on the folded portion. The configuration in Figure 39 allows for radial expansion of the sheath 100 as an outward-directed radial force is applied from the inside (for example, by passing a medical device such as an artificial heart valve into the lumen 116). When a radial force is applied, the folded portion 118 can be separated, straightened, and / or spread out, and / or the overlapping portion 120 and the lower portion 122 of the outer layer 110 can slide circumferentially relative to each other, thereby allowing the diameter of the lumen 116 to expand.

[0213] In this way, the sheath 100 is configured to expand from a static configuration (Figure 39) to an expanded configuration shown in Figure 40. In the expanded configuration, as shown in Figure 40, an annular gap 132 may be formed between the overlapping portion 120 of the outer layer 110 and the longitudinal edge of the lower layer portion 122. As the sheath 100 expands at a particular location (i.e., locally at the location of the prosthesis being passed through), the overlapping portion 120 of the outer layer 110 can move circumferentially relative to the lower layer portion 122 as the folded portion 118 of the inner layer 108 expands. This movement can be facilitated by the use of a low-friction material for the inner layer 108, such as PTFE. Furthermore, the folded portion 118 can be at least partially separated and / or expanded to accommodate medical devices having a diameter larger than the diameter of the lumen 116 in the static configuration. As shown in Figure 40, in some embodiments, the folded portion of the inner layer 108 can be fully unfolded so that the inner layer 108 forms a cylindrical tube at the location of the expanded configuration.

[0214] The sheath 100 may be configured to expand locally at specific locations corresponding to the location of a medical device along the length of the lumen 116, and then to contract locally as the medical device passes through those specific locations. Thus, as the medical device is introduced through the sheath, bulges may be visible that advance longitudinally along the length of the sheath, and as the device advances along the length of the sheath 100, representing continuous local expansion and contraction. In some embodiments, each segment of the sheath 100 may contract locally after the removal of any radially outward force to restore the original resting diameter of the lumen 116.

[0215] Layers 108 and 110 of the sheath 100 may be configured as shown in Figure 39 along at least a portion of the length of the sheath 100. In some embodiments, layers 108 and 110 may be configured as shown in Figure 39 along length A (Figure 35), extending from a location adjacent to the soft tip portion 102 to a location closer to the proximal end 106 of the sheath 100. In this case, the sheath is expandable and contractible only along a portion of the length of the sheath corresponding to length A (typically corresponding to the section of the sheath inserted into the narrowest section of the patient's vascular system).

[0216] Figures 53 and 54 show additional cross-sectional views obtained at different points along the sheath 100, including an elongated tube 140 disclosed herein, which acts as the outer jacket of the sheath. Similar to Figure 38, Figure 53 shows a cross-section of a segment of the sheath near the proximal end 106 of the sheath 100, as indicated by lines 38-38 in Figure 35. At this location, the sheath 100 may comprise an inner layer (inner liner) 108, an outer layer 110, an adhesive layer 128, and a second outer layer (outer jacket) 140. In this exemplary embodiment, at this location near the proximal end of the sheath, layers 108, 110, and 140 may be substantially tubular, with no slits or folded portions within the layers. In contrast, layers 108 and 110 at different locations along the sheath 100 (for example, at the points indicated by lines 39-39 in Figure 35) may have different configurations, while the second outer layer (outer jacket) 140 maintains a substantially tubular shape without slits or folds. It is understood that the outer jacket 140 may have any composition and properties of the elongated tube disclosed above, as shown herein.

[0217] As shown in Figure 54 and as described above with respect to Figure 39, the inner layer (inner liner) 108 may be arranged to form a substantially cylindrical lumen 116 extending through it. The inner layer 108 may include one or more folded portions 118. The outer layer 110 may be arranged in an overlapping manner such that when the sheath is not expanded, the overlapping portion 120 overlaps at least a portion of the folded portions 118 of the inner layer 108 and the lower portion 122 (positioned to be below the folded portions 118 of the inner layer 108). The sheath 100 is configured to expand locally from a non-expanding configuration in which the lumen 116 has a first diameter to an expanded configuration in which the lumen 116 has a second diameter greater than the first diameter. The sheath 100 expands in response to an outward-directed radial force exerted on the inner layer 108 by the medical device as it passes through the lumen 116. During expansion, the first fold / folded edge moves closer to the second fold / folded edge, shortening the folded portion 118. As shown in Figure 55, in some embodiments, the folded portion 118 of the inner layer 108 can fully expand so that the inner layer (inner liner) 108 forms a cylindrical tube at the location of the expanded configuration. When the sheath is expanded, a portion of the inner layer 108 extends through an opening / gap provided within the outer layer 110, the opening being formed by the longitudinally extending edge of the overlapping portion 120 and the longitudinally extending edge of the lower layer portion 122. As the prosthesis passes through, the sheath 100 then locally contracts, at least partially back to the non-expanded configuration.

[0218] As described above, the sheath 100 includes an inner layer 108. The inner layer 108 may be surface-treated by plasma etching, chemical etching, or other preferred methods of surface treatment. In certain embodiments, the inner liner 108 is selectively etched to form various etched and unetched portions, as disclosed above. By treating the surface of the inner layer 108, the outer surface of the inner layer 108 may have areas with modified surface angles that can provide better adhesion between the inner layer 108 and the outer layer 110. As described above, the inner liner 108 may include polytetrafluoroethylene (PTFE), polyimide, polyetheretherketone (PEEK), polyurethane, nylon, polyethylene, polyamide, or a combination thereof. In the exemplary sheath 100, the inner layer 108 is composed of an etched PTFE material. The inner layer 108 is intended to have a fully etched outer surface or a partially etched outer surface. When partially etched, the unetched portions of the outer surface of the inner liner 108 can extend longitudinally along the length of the inner layer 108 and / or circumferentially around the circumference of the inner layer 108. For example, desired unetched locations on the inner layer 108 can be masked or otherwise covered during the etching process to prevent etching at those locations. It is also intended that the entire outer surface of the inner liner 108 may be etched, and that etching may occur at desired locations on the unetched surface.

[0219] In the exemplary sheath 100, the unetched portions are provided along the surface of the inner layer 108 that is in contact with the outer surface of the outer layer 110. That is, those portions of the inner layer 108 that exclude the tie layer 130 will not contain etching. For example, etching is intended not to be included between the inner surface of the folded portion 118 of the inner layer 108 and the lower portion 122 of the outer layer 110. By excluding etching on the portions where the outer surfaces of the inner layer 108 and the outer layer 110 are in direct contact, it is helpful to facilitate the release of the inner surface of the folded portion 118 and the outer layer 110 during the expansion of the sheath 100.

[0220] The wall thickness of the inner liner may vary, but in some embodiments, the wall thickness of the inner layer 108 ranges from approximately 0.002 inches to approximately 0.006 inches (including approximately 0.002 inches, approximately 0.003 inches, approximately 0.004 inches, approximately 0.005 inches, and approximately 0.006 inches). In other embodiments, the wall thickness of the inner layer ranges from approximately 0.003 inches to approximately 0.005 inches. In further embodiments, the wall thickness of the inner layer (inner liner) 108 ranges from approximately 0.0035 inches to approximately 0.0045 inches (including approximately 0.0035 inches, approximately 0.0040 inches, and approximately 0.0045 inches).

[0221] As described above, the sheath 100 includes an outer layer 110 that exerts a radially inward force on the inner layer 108. Generally, the outer layer 110 may include polymer materials. As described above, the outer layer 110 may consist of PTFE, polyimide, PEEK, polyurethane, nylon, polyethylene, polypropylene, polyamide, polyether block amide, polyether block ester copolymer, thermosetting silicone, latex, polyisoprene rubber, high-density polyethylene (HDPE), Tecoflex®, or a combination thereof. In exemplary embodiments, the inner layer 108 may include PTFE, and the outer layer 110 may include a combination of HDPE and Tecoflex®. The outer layer 110 may have a wall thickness in the range of approximately 0.007 inches to approximately 0.013 inches (including approximately 0.007 inches, approximately 0.008 inches, approximately 0.009 inches, approximately 0.010 inches, approximately 0.011 inches, approximately 0.012 inches, and approximately 0.013 inches). In another embodiment, the outer layer 110 may have a wall thickness in the range of approximately 0.008 inches to approximately 0.012 inches. In yet another embodiment, the outer layer 110 may have a wall thickness in the range of approximately 0.009 inches to approximately 0.011 inches.

[0222] As described above, the sheath 100 includes an outer jacket 140 that extends over and encloses the outer layer 110. The outer layer 110 may be discontinuous in that it includes slits or cuts to form overlapping and lower layers 120, 122 as described above, while the outer jacket 140 has a continuous outer layer covering the inner and outer layers 108, 110. It is understood that the outer jacket is formed of elongated tubes as disclosed above having the disclosed composition and properties.

[0223] Generally, the outer jacket 140 has a relatively low tensile modulus compared to the inner and outer layers 108, 110. In certain embodiments, as disclosed above, the outer jacket exhibits a break elongation in the range of about 40% to about 800% (including about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 100%, about 150%, about 200%, about 250%, about 300%, about 350%, about 400%, about 450%, about 500%, about 550%, about 600%, about 650%, about 700%, and about 800%).

[0224] The outer jacket 140 in this embodiment may have a first polymer layer and a second polymer layer, similar to the embodiments disclosed above. For example, the first polymer layer may include a first composite composition comprising a polymer comprising more than 0% to 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of an inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of a solid lubricating filler based on the total weight of the first composite composition. In a further embodiment, the first polymer layer may also include at least one tackiness-reducing compound in an amount of about 1% to about 20% by weight. In a further embodiment, the solid lubricating filler may include one or more of graphene, reduced graphene oxide, carbon black, boron nitride, silicone, talc, polytetrafluorinated polyethylene (PTFE), fluorinated ethylene propylene, and equivalents. In further embodiments, the inorganic filler may include bismuth chloride oxide, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof. In even further embodiments, as disclosed above, at least one tackiness-reducing compound may include ProPell®.

[0225] In further embodiments, the outer jacket 140 may comprise a second polymer layer. In such embodiments, the second polymer layer may have any of the compositions disclosed above. For example, but not limited to, the second polymer layer may include a second composite composition comprising a second polymer containing 0% to 100% by weight of polyether block amide, polyurethane, or a composition thereof. In even further embodiments, the second composite composition may be substantially free of inorganic fillers. On the other hand, in other embodiments, the second composite composition may be substantially free of solid lubricant fillers.

[0226] The outer jacket 140 may comprise a first polymer layer and / or a second polymer layer having wall thicknesses ranging from approximately 1 mil to approximately 5 mil, including exemplary values ​​of approximately 1.5 mil, approximately 2 mil, approximately 2.5 mil, approximately 3 mil, approximately 3.5 mil, approximately 4 mil, approximately 4.5 mil, and approximately 4.9 mil. The wall thickness is measured radially between the inner surface of the outer jacket 140 and the outer surface of the outer jacket 140.

[0227] In alternative embodiments, the first (and / or second) polymer layer composition and / or wall thickness may vary along the length of the outer jacket 140. For example, the outer jacket (elongated tube) 140 may be provided with one or more segments, and the composition and / or thickness may vary by segment. In exemplary embodiments, the durometer grade of the composition may vary along the length of the outer jacket 140 such that segments near the proximal end contain a stiffer material or combination of materials, while segments near the distal end contain a softer material or combination of materials. Similarly, the wall thickness of the outer jacket 140 in segments near the proximal end may be thicker / greater than the wall thickness of the outer jacket 140 near the distal end.

[0228] As shown in Figures 71-72, the outer jacket 140 includes one or more axial reinforcing members 145 that extend longitudinally along all or part of the outer jacket 145. The reinforcing members 145 help prevent axial accumulation of the outer jacket 140 during insertion into the patient's vascular system without sacrificing the radial expansion force of the outer jacket 140.

[0229] As shown in Figure 35, the sheath 100 may include a tapered segment adjacent to the wide-mouth portion 114 at the proximal end of the sheath 100. The tapered segment and the wide-mouth portion 114, referred to as the strain relief section, help to facilitate the transition between the smaller diameter portion of the sheath 100 and the housing 101. The thickness and / or composition of the outer jacket 140 may be adjusted to improve the performance of the strain relief section and to reduce the pressing force as disclosed above.

[0230] The outer jacket (or slender tube) 140 is bonded to the outer layer 110 and can prevent the slender tube 140 from sliding across the outer layer 110 and "accumulating" in response to frictional forces applied by surrounding tissues during insertion of the sheath 100 into the patient's vascular system. For example, the outer jacket (slender tube) 140 may be bonded at the proximal and / or distal ends of the outer layer 110. At the proximal and distal ends, the outer jacket 140 may be bonded to the outer layer 110 around the entire circumference of the outer layer. At the distal end of the sheath 100, the outer jacket (slender tube) 140 may alternatively be bonded to the inner layer 108. For example, the outer jacket (slender tube) 140 may be bonded to the distal end surface of the inner layer 108.

[0231] As illustrated in Figure 57, the outer jacket (elongated tube) 140 may be joined 144 to the outer layer 110 at a circumferential location opposite the folded portion 118 of the inner layer 108. As provided in Figures 58-59, the joint 144 may be a spot joint or a linear joint line extending along all or part of the outer layer 110. As provided in Figure 57, the joint line / spot 144 will also have a width extending circumferentially around the outer layer 110. For example, the joint line may cover about 5° to about 90° of the circumference of the outer layer 110 (including about 5°, about 10°, about 15°, about 20°, about 25°, about 30°, about 35°, about 40°, about 45°, about 50°, about 55°, about 60°, about 65°, about 70°, about 75°, about 80°, about 85°, and about 90°).

[0232] The outer jacket (elongated tube) 140 can be joined to the outer layer 110 and / or inner layer 108 using any mechanical and / or chemical (e.g., adhesive) fasteners known in the art. In one embodiment, the sheath 100, the outer jacket 140, and the outer layer 110 and / or inner layer 108 may have similar melting temperatures. Thus, exemplary joining methods include thermal joining between the outer jacket (elongated tube) 140, the outer layer 110, and / or inner layer 108. For example, joining between the outer jacket 140 and the outer layer 110 can be achieved by laser welding and / or thermal compression (e.g., using thermal compression jaws), allowing for precise control of the location of the joint line.

[0233] As shown in Figure 54, and as described above with respect to Figure 39, an adhesive layer 128 (e.g., a tie layer) is provided between the inner layer 108 and the outer layer 110 to at least partially bond the inner layer 108 to the outer layer 110. That is, the adhesive layer 128 is selectively provided / located between the inner layer 108 and the outer layer 110 and bonds the inner and outer layers 108, 110 at selected locations of the adhesive layer 128.

[0234] As illustrated in Figure 54 (and Figure 39), the adhesive layer 128 is provided on the outer surface of the inner liner 108 and / or on the inner surface 130 of the outer layer 110. For example, the adhesive layer 128 may be provided partially or completely around the outer surface of the inner liner 108. In addition, or alternatively, the adhesive layer 128 may be provided partially and / or completely around the inner surface 130 of the outer layer 110. As illustrated in Figure 54, the adhesive layer 128 extends between the outer layer 110 and the overlapping folded portion 118 of the inner layer 108. That is, the adhesive layer 128 extends between the outer surface of the folded portion 118 of the inner layer 108 and the corresponding inner surface of the overlapping portion 120 of the outer layer 110. As illustrated in Figure 54, the adhesive layer 128 does not extend between the inner surface of the overlapping folded portion 118 of the inner layer 108 and the corresponding surface of the lower portion 122 of the outer surface of the outer layer 110. Removing the adhesive layer 128 on the portion of the sheath between the inner surface of the folded portion 118 and the lower portion 122 facilitates the expansion of the sheath and prevents undesirable bonding / adhesion between the inner and outer layers 108, 110 in this location.

[0235] The adhesive material 128 may include a material having a Shore A hardness (durometer) of less than approximately 90 A. For example, the adhesive material 128 may include a thermoplastic polyurethane such as an aliphatic polyether-based thermoplastic polyurethane (TPU). An example of a TPU is Tecoflex® 80A. The adhesive layer 128 may also consist of an aromatic polyether or polyester-based thermoplastic polyurethane such as Pellethane® 80A. The adhesive layer may also consist of a polyolefin or polyamide, including a maleic anhydride-modified polyolefin (PE, PP, or EVA) such as Orevac® resin.

[0236] The thickness (wall thickness) of the adhesive layer 128 may vary, but in some embodiments, the wall thickness of the adhesive layer is in the range of approximately 0.002 inches to approximately 0.005 inches (including approximately 0.002 inches, approximately 0.003 inches, approximately 0.004 inches, and approximately 0.005 inches). In other embodiments, the wall thickness of the adhesive layer 128 is in the range of approximately 0.0025 inches to approximately 0.0040 inches (including approximately 0.0025 inches, approximately 0.0030 inches, approximately 0.0035 inches, and approximately 0.0040 inches). In further embodiments, the wall thickness of the adhesive layer 128 is in the range of approximately 0.0025 inches to approximately 0.0035 inches (including approximately 0.0025 inches, approximately 0.0030 inches, and approximately 0.0035 inches).

[0237] In some embodiments, the sheath 100 may include a lubricant to reduce friction and facilitate expansion / contraction between the outer layer 110 and the outer jacket 140. The lubricant 142 allows the outer layer 110 and inner layer 108 to expand easily under the outer jacket (elongated tube) 140, ensuring that the hemostatic and non-traumatic benefits achieved by the addition of the outer jacket 140 do not impair the pressing force performance of the sheath 100. Specifically, the lubricant 142 reduced the pressing force required to move the prosthesis through the central lumen 116 of the inner layer 108 during prosthesis delivery and corresponding local expansion of the sheath 100.

[0238] As shown in Figure 56, the lubricant 142 may be selectively applied along the outer surface of the outer layer 110 adjacent to the longitudinally extending edge 126 of the overlapping portion 120. In some embodiments, a portion of the folded portion 118 of the inner layer 108 extends along the outer surface of the outer layer 110 beyond the longitudinally extending edge 126 of the overlapping portion 120. In this embodiment, the lubricant 142 is also provided along the protruding portion, and the folded portion 118 of the inner layer 108 extends along the outer surface of the outer layer 110 (beyond the edge 126). In this location, the lubricant 142 also reduces friction between the outer jacket 140 and the inner layer 108 during expansion of the sheath 100. As shown in Figure 56, the lubricant 142 extends around the circumference of the outer layer 110 beyond the protruding portion of the folded portion 118.

[0239] The lubricant is applied as a band (or spot) extending both circumferentially and longitudinally along the outer layer 110 (and the protruding portion of the inner layer 108). In the exemplary sheath 100, the lubricant 142 is applied as a band extending both circumferentially around the outer layer 110 and longitudinally along the length of the outer layer 110. To prevent movement, the lubricant 142 may consist of a thermosetting material, for example, a material that can be cured at room temperature. As a result, the material can be applied to desired locations along the outer layer 110 and will not move during the assembly and / or use of the sheath 100. The lubricant 142 may consist of a medical-grade lubricant such as silicone. Exemplary lubricants include medical-grade curable silicone lubricants, including platinum-catalyzed thermosetting silicone lubricants such as NuSil® MED10-6670 (thermosetting), and PTFE lubricants such as Duraglide® (curable at room temperature) and / or CHRISTO-LUBE®.

[0240] Figure 60A illustrates an additional embodiment of the sheath 100 of Figure 35. In this embodiment, the sheath 100 may include a coiled wire 160 or a coiled wire mesh along the length of the sheath 100. The coiled wire 160 provides uniform bending of the sheath and prevents twisting. The coiled wire 160 may be embedded in the outer layer 110. For example, the coiled wire 160 may be co-extruded with the outer layer 110. Alternatively, the coiled wire 160 may be provided between the outer layer and the adhesive layer 128. In another embodiment, the coiled wire 160 is at least partially embedded within both the outer layer 110 and the adhesive layer 128. For example, the coiled wire 160 may be provided on the outer surface of the adhesive layer 128, and the outer layer 110 is reflowed.

[0241] As shown in Figure 60A, the coiled wire 160 defines a helical path around the longitudinal axis of the sheath 100. Embodiments of the coiled wire 160 include overlapping helical paths around the longitudinal axis of the sheath 100, resulting in a continuous rhombic pattern along the length of the sheath.

[0242] The coiled wire 160 may consist of a metal or polymer wire. For example, the coiled wire 160 may consist of PET, PEEK, stainless steel, and / or nitinol. The coiled wire 160 may consist of flat wires, circular wires, or a combination thereof. Individual wires of the coiled wire 160 may have a diameter / thickness in the range of about 0.002 inches to about 0.008 inches (including about 0.002 inches, about 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, and about 0.008 inches). In another embodiment, individual wires of the coiled wire 160 may have a diameter / thickness in the range of about 0.004 inches to about 0.007 inches. In a further embodiment, individual wires of the coiled wire 160 may have a diameter / thickness of about 0.006 inches. The pitch / distance between adjacent coils of coiled wire 160 can correspond to the diameter / thickness of the coiled wire. For example, if the diameter / thickness of a single coil of coiled wire is approximately 0.006 inches, then the spacing / pitch between the wire and the next adjacent coiled wire is approximately 0.006 inches.

[0243] The method of using the sheaths shown in Figures 53 to 60A involves first inserting the expandable sheath 100 into the target vascular system and advancing the prosthesis through the inner layer 108 / inner lumen 116 of the sheath 100. The prosthesis applies an outward-directed radial force to the inner layer 108 of the expandable sheath 100. In some embodiments, the outward-directed radial force is transmitted through the inner layer 108, the adhesive layer 128, and the outer layer 110. The lumen 116 of the sheath 100 expands at the axial location of the prosthesis due to the outward-directed radial force exerted by the prosthesis against the inner surface of the lumen during advancement. During the expansion of the lumen 116, the first fold (folded edge) of the folded portion 118 is moved circumferentially closer to the second fold (folded edge), shortening the overlapping portion of the folded portion 118 that extends circumferentially between the first and second folds, thereby increasing the circumference of the lumen 116.

[0244] As the sheath 100 expands at a specific location (i.e., locally at the location of the prosthesis passing through), the overlapping portion 120 of the outer layer 110 moves circumferentially relative to the lower portion 122 as the folded portion 118 of the inner layer 108 separates at least partially and / or expands, allowing the narrow gap 132 provided within the outer layer 110 to expand / increase. Thereafter, the sheath expands to accommodate medical devices having a diameter larger than the diameter of the lumen 116 in the stationary (non-expanded) configuration. In some embodiments, as shown in Figure 55, the folded portion of the inner layer 108 can expand completely so that the inner layer 108 forms a cylindrical tube at the location of the expanded configuration. As illustrated in Figures 54 and 55, the narrow gap 132 is generally aligned with the longitudinal axis of the lumen 116 so that the expanded portion of the inner layer 108 expands into the gap 132 during expansion.

[0245] In a non-expanded configuration, the sheath 100 may have an outer diameter of less than approximately 0.30 inches (including less than approximately 0.29 inches, less than approximately 0.28 inches, less than approximately 0.27 inches, less than approximately 0.26 inches, less than approximately 0.25 inches, and less than approximately 0.24 inches). Preferably, an unexpanded sheath has an outer diameter in the range of approximately 0.24 inches to approximately 0.26 inches. In a fully expanded configuration, the sheath 100 may have an inner diameter greater than 0.300 inches. Preferably, the expanded sheath 100 has an inner diameter in the range of 0.325 inches to 0.400 inches (including approximately 0.325 inches, approximately 0.327 inches, approximately 0.330 inches, approximately 0.333 inches, approximately 0.336 inches, approximately 0.340 inches, approximately 0.345 inches, approximately 0.350 inches, approximately 0.355 inches, approximately 0.360 inches, approximately 0.365 inches, approximately 0.370 inches, approximately 0.375 inches, approximately 0.380 inches, approximately 0.385 inches, approximately 0.390 inches, and approximately 0.395 inches).

[0246] As described above, the inner and outer layers 108, 110 can be joined together using an adhesive layer 128. The adhesive layer 128 prevents both longitudinal and radial movement between the inner layer 108 and the outer layer 110. As a result, the expansion of the sheath 100 can be limited to areas excluding the adhesive layer 128. For example, as shown in Figure 54, since the adhesive layer 128 is not provided between the inner surface of the folded portion 118 and the lower portion 122 of the outer layer, the expansion of the sheath extends the inner surface of the folded portion into the gap 132 created between the first and second edges 124, 126 of the expanded outer layer 110.

[0247] Once the prosthesis is passed through the lumen 116 (or a specific location along the lumen), the lumen 116 of the sheath can be at least partially contracted back to its non-expanded configuration. The outer layer 110 exerts an inwardly directed radial force on the inner layer 108, pushing the inner layer 108 back to its original folded configuration. Similarly, if a coiled wire 160 is included, the coiled wire exerts an inwardly directed radial force on the outer layer 110 and the inner layer 108, pushing them back towards their non-expanded configuration. In a further embodiment, the outer jacket 140 exerts an inwardly directed radial force on the outer layer 110 and the inner layer 108, pushing them back towards their non-expanded configuration.

[0248] The prosthesis can be delivered to the delivery site in the patient through the distal end of the sheath 100. The prosthesis may include a self-expanding heart valve or a stent-equipped heart valve. The heart valve may extend through the distal end of an elongated lumen 116 at the delivery site. Outside the lumen 116, the heart valve may be expanded, and the sheath 100 may be removed from the treatment site.

[0249] Figures 41 to 49 illustrate additional embodiments and modifications of the general sheath 100 described above. It should be understood that any modifications described above (e.g., materials and alternative configurations) may also apply to the embodiments shown in Figures 41 to 49, and vice versa, with reference to any previously disclosed figures and embodiments.

[0250] Figures 41 to 43 illustrate a sheath 700, which also includes a strain-relieving cover, further comprising elongated tubes 702 as disclosed herein, positioned around at least a portion of the inner layer 704 and the outer layer 706. As shown in Figure 41, the elongated tubes (outer jacket or strain-relieving jacket) 702 may extend along at least a portion of the body of the sheath 700 for a length L. In some embodiments, the elongated tubes 702 may extend from the proximal end 708 of the sheath 700 toward the distal end 709 of the sheath. In some embodiments, the elongated tubes 702 extend only for a portion of the length of the sheath 700. In alternative embodiments, the elongated tubes 702 may extend to a point adjacent to the distal end 709, or may extend entirely to the distal end 709 of the sheath 700. Furthermore, the elongated tubes 702 do not need to extend entirely to the proximal end 708 of the sheath 700. In some embodiments, the elongated tube 702 may extend only partially toward the proximal end 708. In some embodiments, the longitudinal length L of the elongated tube 702 may range from about 10 cm to the total length of the sheath 700.

[0251] As shown in Figures 42 and 43, the elongated tube 702 may be a continuous tubular layer without slits or other discontinuities. The elongated tube 702 may be positioned to surround the entire circumference of the outer layer 706 and may extend longitudinally along any portion of the length of the sheath 700. The elongated tube 702 may contain any of the above compositions.

[0252] In some embodiments, the elongated tube 702 can provide hemostasis (for example, to prevent blood loss during implantation of an artificial prosthesis). For example, the elongated tube 702 may be sized or configured to form a seal with the patient's artery when inserted, such that blood is substantially prevented from flowing between the elongated tube 702 and the blood vessel wall. The elongated tube 702 may be inserted to pass through an arterial incision. For example, in embodiments where the elongated tube 702 does not extend entirely to the distal end 709 of the sheath 700, the elongated tube 702 may extend distally far enough so that at least a portion of the elastic outer cover extends through the arterial incision site when the sheath 700 is fully inserted into the patient.

[0253] The elongated tube 702 may be configured to expand as the sheath expands, as shown in the expansion configuration of Figure 43.

[0254] Figure 42 shows a cross-section of the sheath 700 in a stationary configuration having an inner diameter D1. Figure 43 shows a cross-section of the sheath 700 in an expanded configuration having an inner diameter D2, where D2 is greater than D1. Similar to the embodiments in Figures 35 to 40, the sheath 700 may include an inner layer 704 having a folded portion 710 and an outer layer 706 having an overlapping portion 712 and a lower portion 714. The overlapping portion 712 overlaps at least a portion of the folded portion 710 of the inner layer, and the lower portion 714 is below at least a portion of the folded portion 710. As shown in Figures 42 to 43, in some embodiments, the overlapping portion 712 does not overlap the entire folded portion 710 of the inner layer 704, and therefore a portion of the folded portion 710 may be directly adjacent to the elongated tube 702 where the elongated tube 702 is present. Where the elongated tube 702 is not present, a portion of the folded portion 710 may be visible from the outside of the sheath 700, as seen in Figure 41. In these embodiments, the sheath 700 may include a longitudinal seam 722 where the overlapping portion 712 terminates in the folded portion 710. When in use, the sheath may be positioned such that the seam 722 is behind a point on the sheath that is 180 degrees from the seam 722 (for example, facing downward in the diagram of Figure 41). The seam 722 can also be seen in Figure 41, indicating that the seam 722 does not need to extend along the entire length of the sheath. In some embodiments, the proximal end portion of the sheath includes two layers without a folded portion (for example, similar to Figure 38), while the distal end portion of the sheath includes two layers with a folded portion (for example, similar to Figure 39). In some embodiments, the seam 722 may terminate at a transition point between a portion of the sheath having a folded inner layer and a portion of the sheath not having a folded inner layer.

[0255] In some embodiments, the folded portion 710 may include weakened sections such as longitudinal perforations, cut lines, and / or slits 716 along at least a portion of the length of the inner layer 704. The slits 716 may allow two adjacent ends 718, 720 of the folded portion 710 to move relative to each other as the sheath 700 expands to the expanded configuration shown in Figure 43. When an instrument having an outer diameter larger than the initial stationary inner diameter of the sheath 700 is inserted through the sheath 700, the instrument may cause local expansion of the sheath 700, allowing the sheath 700 to expand at the location of the partial cut or dividing line 716. The weakened sections 716 may extend longitudinally along any portion of the expandable sheath 700.

[0256] Figures 44 and 45 show another embodiment of an expandable sheath 800 having an initial diameter in a static configuration (Figure 44) and a larger expanded diameter in an expanded configuration (Figure 45). The sheath 800 may include the elongated tube 802 disclosed above, an inner layer 804, and an outer layer 806. The inner layer 804 may include first and second folded portions 808, 810. The folded portions 808, 810 may be arranged such that they fold away from each other in opposite directions around the circumference of the sheath 800. For example, in the diagram of Figure 44, folded portion 808 can be folded to the right and folded portion 810 can be folded to the left so that the folded portions do not overlap with each other but share a common segment 812 which is part of both folded portions 808, 810. In contrast to previous embodiments, the outer layer 806 in this embodiment does not include any overlapping portions, but rather has first and second lower layers 814, 816, respectively, located beneath the first and second folded portions 808, 810. The inner layer 804 can extend through gaps between the ends of adjacent lower layers 814, 816 (for example, between the first and second discontinuous ends of the outer layer 806).

[0257] Each folded portion 808, 810 may include a weakened portion 818 such as a slit, notch, and / or perforation. The weakened portion 818 may allow the expandable sheath 800 to expand easily without high radial force. As the sheath 800 expands, the segment 812 along the top of the folded portions 808, 810 of the inner layer 804 may be configured to separate away from the rest of the folded portions 808, 810, and the first and second lower portions 814, 816 may move away from each other to form an expanded lumen within the inner layer 804. The weakened portion 818 may allow the segment 812 to easily separate away from the inner layer 804 as the sheath 800 expands.

[0258] Figures 46-47 show another embodiment of the expandable sheath 900. The sheath 900 may provide an inner layer 902 and an elongated tube 904 surrounding the inner layer 902. Although not shown, the sheath 900 may also include an intermediate layer positioned between the inner layer 902 and the elongated tube 904. If present, the intermediate layer can closely follow the contour of the inner layer 902.

[0259] The inner layer 902 may be molded to include one or more folded portions 906 arranged to form a substantially horseshoe-shaped lumen 908 that extends longitudinally along the inner surface of the inner layer 902 through the sheath 900. The folded portions 906 may be positioned together with the lumen 908 and arranged to form a region 910 radially inward from the elongated tube 904. In some embodiments, the region 910 may include one or more voids (e.g., smaller lumens or openings extending through the portions 910). In some embodiments, the region 910 may be filled with material reflowed from the intermediate layer (e.g., HDPE) while the sheath is being manufactured. In some embodiments, the region 910 may be filled with material reflowed from the elongated tube 904 during the sheath manufacturing process.

[0260] The inner layer 902 may include one or more weakened portions 912, such as notches, perforations, or slits. The weakened portions 912 may be configured to split, separate, or expand in the presence of radial forces as the sheath expands from its initial stationary configuration (Figure 46) to its expanded configuration (Figure 47). As the sheath 900 expands, material from region 910 can cover any gaps 914 formed in the weakened portions 912, thereby keeping the lumen 908 substantially sealed.

[0261] Figure 48 shows another embodiment of an expandable sheath 1000 having an inner layer 1002 and a discontinuous outer layer 1004. The sheath 1000 is shown without the elongated tube disclosed herein in which the sheath 1000 behaves as an outer jacket, and is further similar to the sheath 800 of Figure 44, except that the inner layer 1002 is continuous without the weakened portion at the fold 1006. As shown in Figure 48, the inner layer 1002 may be configured to have one or more folds 1006 (e.g., two folds located on the outer surface of the outer layer 1004) in which a portion 1008 of the outer layer 1004 extends between the fold 1006 and the outer surface 1010 of the inner layer 1002 below the fold 1006.

[0262] Figure 49 shows yet another embodiment of an expandable sheath 1100 having an inner layer 1102 and an outer layer 1104. The sheath 1100 is similar to the sheath 100 shown in Figure 39 in that the inner layer 1102 is continuous with the folded portion 1106, and the outer layer 1104 may be discontinuous with the folded portion 1108 which overlaps with at least a portion of the folded portion 1106 and the lower portion 1110 which is below at least a portion of the folded portion 1106. Thus, the lower portion 1110 may be positioned between the outer surface 1112 of the lumen-forming portion of the inner layer 1102 and the folded portion 1106.

[0263] The inner layers 1002 and 1102 of the sheaths 1000 and 1100 in Figures 48 and 49 can be optimized to function slightly differently from the inner layers of the sheaths described above. For example, different materials can be used for the inner liner to enhance the durability and flexibility of the seam (however, such materials can also be used in conjunction with other embodiments of the expandable sheaths described above). For example, materials such as woven or braided filaments can be used. Such fabrics, filaments, or threads may include, for example, PTFE, PET, PEEK, and / or nylon threads or filaments. These materials can advantageously provide a soft and flexible layer that can be easily formed into the desired shape or folded portion. In addition, such materials can withstand high temperatures and possess high tensile strength and tear resistance. Nevertheless, these materials can also be elastic, withstand minimal twisting, and provide a soft distal end for low-traumatic insertion into the patient's blood vessels.

[0264] It will be further understood that the embodiments disclosed herein that describe the presence of an outer layer in addition to the inner layer and elongated tubes (outer jacket) are exemplary. The embodiments also describe embodiments in which this outer layer is completely replaced by elongated tubes containing the composition disclosed herein. In such embodiments, the elongated tubes may have the structure and properties of the outer layer disclosed herein. In such exemplary and non-limiting embodiments, it will be further understood that additional elongated tubes may exist and act as the outer jacket or strain-relieving jacket disclosed herein.

[0265] The elongated tubes of the present disclosure can be used as an outer jacket 140 in various sheath configurations, as shown in Figures 60B and 71-77. A sheath comprising the elongated tubes of the present disclosure (or, if used synonymously, the “outer jacket”) may also comprise one or more axial reinforcing members 145 extending longitudinally along all or part of the outer jacket 140. The layers 145 may be located within a first polymer layer, within a second polymer layer, or between the first and second layers.

[0266] As used herein, the axial reinforcement member may also be used synonymously with the term "at least one intermediate reinforcement layer." In certain embodiments, the at least one intermediate reinforcement layer may be presented as a strip. On the other hand, in yet another embodiment, the at least one intermediate reinforcement layer may be a thermally bondable layer. Furthermore, in yet another embodiment, this thermally bondable layer may also be presented as a strip.

[0267] The reinforcing member 145 provides rigidity and prevents axial accumulation of the outer jacket 140 during insertion into the patient's vascular system, without sacrificing the low radial expansion force of the outer jacket 140.

[0268] As illustrated in Figure 35, the sheath 100 may include a tapered segment adjacent to the wide-mouth portion 114 at the proximal end of the sheath 100. The tapered segment and the wide-mouth portion 114, referred to as the strain-relieving section, help to facilitate the transition between the smaller diameter portion of the sheath 100 and the housing 101. The thickness and / or composition of the outer jacket 140 may be adjusted to increase the durometer and / or stiffness along the strain-relieving section. Since this portion of the sheath 100 is typically outside the patient's body during the procedure, providing the outer jacket 140 with increased durometer and / or stiffness along the strain-relieving section helps to withstand the blood pressure that would otherwise "swell" the outer jacket 140 with body fluids / blood. As a result, this allows the sheath 100 to have a relatively stiff proximal end at the point of introducing the delivery device, while still having a relatively soft distal end at the point of entry into the patient's blood vessels.

[0269] As disclosed herein, the elongated tube or outer jacket may have the same diameter across the length of the sheath or may have different diameters across the length of the sheath. Figure 73 is an elevation view of the outer jacket 140 showing a tapered segment adjacent to the wide-mouth end at the proximal end of the sheath. Figure 74 is a cross-sectional view of the outer jacket 140 obtained along section AA of Figure 73. As described above, the tapered portion is referred to as the strain-relieving section, and the tapered segment and the wide-mouth proximal end help to facilitate the transition between the smaller diameter portion of the sheath 100 and the housing 101. The length of the proximal end (L1) may range from 1,600 inches to 2,400 inches. In some embodiments, the length of the proximal end is about 2,000 inches. The length of the tapered segment (L2) may range from 2,000 inches to 3,000 inches. In some embodiments, the length of the tapered segment (L2) is about 2,500 inches. The total length (L3) of the outer jacket 140 / sheath 100 may range from 17,600 inches to 26,400 inches. In some embodiments, the total length (L3) of the outer jacket 140 / sheath 100 is approximately 22,000 inches.

[0270] As provided in Figure 73, the diameter of the outer jacket 140 at the proximal end is greater than the diameter of the outer jacket 140 at the distal end. This allows the outer jacket 140 to slide across the inner and outer layers 108, 110 without needing to expand. For example, the diameter of the outer jacket 140 at the proximal end may range from 0.264 inches to 0.396 inches. In some embodiments, the diameter of the outer jacket 140 at the proximal end is approximately 0.330 inches. The diameter of the outer jacket 140 at the distal end may range from 0.176 inches to 0.264 inches. In some embodiments, the diameter of the outer jacket at the distal end is approximately 0.220 inches.

[0271] Additional embodiments of the sheath, comprising an elongated tube disclosed herein, are shown in Figures 61A-C. In such embodiments, the sheath further comprises a variable-diameter inner liner comprising a sheet having a first edge and a second edge, and defined by an inner and outer surface, wherein the sheet is wound in a helical configuration such that at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, the first edge of the sheet is slidable along at least a portion of the inner surface of the sheet, and the second edge is slidable along at least a portion of the outer surface of the sheet, the inner surface of the sheet defines a cylindrical lumen having a longitudinal axis, and the variable-diameter inner liner, while a radially outward force is applied due to the passage of a medical device through the lumen of the inner liner, slides the first edge of the sheet along at least a portion of the inner surface and slides the second edge of the sheet along at least a portion of the outer surface, thereby achieving a predetermined stationary diameter d r The slender tube is configured to expand reversibly from an initial diameter to an expanded diameter d1, and is positioned such that the inner surface of the slender tube covers at least a portion of the outer surface of the inner liner (inner layer).

[0272] Figures 61A and 61B show cross-sectional views of two exemplary sheath embodiments disclosed herein for use with a delivery device such as the one shown in Figure 1. Figure 61C shows a perspective view of one embodiment of an inner liner 202 for use with the disclosed sheath. As shown in Figures 61A-C, in some embodiments the disclosed sheath comprises an inner liner 202 wound in a helical configuration such that at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet to form an overlapping portion 202c, the first edge 202a of the sheet being slidable along at least a portion of the inner surface of the sheet and the second edge 202b being slidable along at least a portion of the outer surface of the sheet. The sheath may further include a braid 204 and an elongated tube 206 disclosed herein, as shown in Figures 61A and 61B. The braid 204 may be, for example, positioned between the inner liner and the elongated tube and not embedded within the elongated tube 206, as shown in Figure 61A. On the other hand, in another embodiment, the braid 204 may be at least partially embedded in the layer of the elongated tube 206, as shown in Figure 61B. In yet another embodiment, the braid 204 and the elongated tube 206 form the outer layer of the sheath.

[0273] In further embodiments, the sheaths disclosed herein do not have braiding. In such exemplary and non-limiting embodiments, a single, elongated tube 206 without braiding forms the outer layer of the sheath.

[0274] In further exemplary and non-limiting embodiments, an additional outer layer may be optionally positioned between the inner liner and the elongated tube.

[0275] The inner liner 202 defines a lumen 201 through which a delivery device can advance into the patient's blood vessels for the purpose of delivering, removing, repairing, and / or replacing the prosthesis. The disclosed sheath may also be useful for other types of minimally invasive surgery, such as any surgical procedure requiring the introduction of a device into the blood vessel of the target. For example, the disclosed sheath may also be used to introduce other types of delivery devices for placing various types of intraluminal devices (e.g., stents, stented grafts, etc.) into many types of blood vessels and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary conduits, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.). In a further exemplary embodiment, the sheath has a predetermined resting diameter d after the medical device has passed through the lumen. r It can be contracted to that extent.

[0276] In further embodiments, the sheet used to produce the inner liner 202 may include high-density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or blends thereof. In further embodiments, the sheet may comprise one or more layers. In some embodiments, if one or more layers are present, each layer may contain the same or different polymers. In further embodiments, the sheet may have a predetermined thickness, which may be defined by those skilled in the art depending on the specific application. In certain embodiments, the predetermined thickness of the inner liner may range from about 0.002 inches to about 0.0025 inches, including exemplary values ​​of about 0.003, about 0.004, about 0.005, about 0.006, about 0.007, about 0.008, about 0.009, about 0.01, about 0.015, and about 0.02 inches. It is further understood that the predetermined thickness of the sheet forming the inner liner 202 may be modified depending on the desired amount of radial expansion and the required strength.

[0277] In further embodiments, the inner surface of the sheet may be at least partially ribbed. In even further embodiments, the sheet may also be lubricating. In some exemplary embodiments, the sheet forming the inner liner may have a coefficient of friction of less than about 0.5, less than about 0.4, less than about 0.3, less than about 0.2, less than about 0.1, or less than about 0.05, or even less than about 0.01. It is further understood that the sheet may have a coefficient of friction having any value between any two of the aforementioned values. Such a liner may facilitate the passage of a delivery device through the lumen 201 of the disclosed sheath. In some further exemplary embodiments, materials that may be used to form a suitable lubricating inner liner include materials that can reduce the coefficient of friction of the inner liner 202, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for lubricating liners also include other materials having a coefficient of friction of about 0.1 or less, about 0.09 or less, about 0.08 or less, about 0.07 or less, about 0.05 or less, about 0.04 or less, about 0.03 or less, about 0.02 or less, or about 0.01 or less.

[0278] In further embodiments, the elongated tube may have any predetermined thickness. It is understood that the predetermined thickness of the elongated tube may depend on the specific application of the sheath. For example, but not limited to, the thicknesses of the inner liner 202, the elongated tube 206, and the braid 204 may also be modified depending on the specific application of the disclosed sheath. In some embodiments, the thickness of the inner liner 202 is in the range of about 0.0005 inches to about 0.010 inches, including exemplary values ​​of about 0.0006, about 0.0007, about 0.0008, about 0.0009, about 0.001, about 0.002, about 0.003, about 0.004, about 0.005, about 0.006, about 0.007, about 0.008, and about 0.009 inches, and in one particular embodiment, the thickness may be about 0.002 inches. In yet another embodiment, the total thickness of the elongated tube 206 and the braid 204 may be between approximately 0.002 inches and approximately 0.015 inches, including exemplary values ​​of approximately 0.003, approximately 0.004, approximately 0.005, approximately 0.006, approximately 0.007, approximately 0.008, approximately 0.009, and approximately 0.01 inches.

[0279] The inner liner may have any shape or configuration depending on the desired application and the size of the delivery device and prosthesis. It is further understood that the inner liner is not limited to a specific shape or configuration. In certain embodiments, the sheath disclosed herein has a stationary diameter d r and outer diameter d o It is defined by the stationary diameter d, as disclosed herein. r However, the outer diameter is defined by the inner liner, while the outer diameter may be defined by the inner liner and the outer layer, the outer layer comprising a braid and an elongated tube.

[0280] Static diameter d of inner liner 202 r This can vary depending on the application and size of the delivery device and prosthesis. In some embodiments, the stationary diameter d r It is understood that the saturation diameter remains virtually uniform along the longitudinal axis of the lumen, without changing from the proximal end to the distal end. In yet another embodiment, the resting diameter d r This can vary along the longitudinal axis of the lumen. In certain embodiments, the resting diameter d at the proximal end is... r The resting diameter d at the distal end is r Larger than. The outer layer comprises a braid and an elongated tube, the outer layer conforming to the shape of the inner liner, and in a further embodiment, the outer diameter d o (Not shown) includes the overall diameter of the inner liner and outer layer. In such embodiments, the outer diameter d o This is defined by the specific use of the sheath.

[0281] resting diameter d r Similarly, the outer diameter d of the non-expanding sheath disclosed herein o The diameter can be substantially uniform (constant) along the longitudinal axis of the lumen without changing from the proximal end to the distal end (not shown). In an alternative embodiment, the original unexpanded outer diameter d of the disclosed sheath is o is the stationary diameter d r Similarly, it can decrease from the proximal end to the distal end. In some embodiments, the stationary diameter d rSimilarly, the original unexpanded outer diameter may decrease along the gradient from the proximal end to the distal end, or the largest original unexpanded outer diameter d is located near the proximal end. o , and the smallest original unexpanded outer diameter d near the distal end o It has a characteristic that can be gradually reduced incrementally along the length of the sheath.

[0282] In some embodiments, the stationary diameter d r The sheath may range from approximately 0.005 inches to approximately 0.400 inches, including exemplary values ​​of approximately 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, and 0.3 inches. As described above, in certain embodiments, the sheath may vary in size. r An inner liner having d can be provided. In such an embodiment, d r The diameter can be any value between any two of the aforementioned values ​​and may depend on the specific application as well as the size and shape of the delivery device and prosthesis. Depending on the size requirements of the delivery device for various applications, different expanded and unexpanded stationary diameters d can be used in different sheaths. r and outer diameter d o This can be provided. In addition, some embodiments can offer more or less extensions depending on the specific design parameters, materials, and / or configurations used.

[0283] As disclosed herein, the outer layer comprises a braid 204 and an elongated tube 206 having a predetermined thickness and an inner and outer surface (as shown in Figures 61A and 61B). In certain embodiments, the braid may be an expandable braid. In further embodiments, the braid may include at least one filament, including stainless steel, nitinol, polymer material, or composite material. In certain non-limiting embodiments, the braid may include a filament, including nitinol and / or other shape memory alloys. In yet another non-limiting embodiment, the braid may have a filament, including polyester or nylon. In several other exemplary embodiments, the braid may include a filament, including Spectra fiber, polyethylene fiber, aramid fiber, or a combination thereof. Again, as described above, the braid 204 is optional, and embodiments without a braid are also disclosed.

[0284] It is understood that the braid may have any configuration known in the art. In particular embodiments, the braid 204 is generally a thin, hollow, substantially cylindrical tube comprising an arrangement, pattern, structure, or configuration of filaments or struts, but other geometric shapes may also be used. Preferred filaments may be circular, having a diameter of less than about 0.015 inches, less than about 0.01 inches, less than about 0.008 inches, less than about 0.005 inches, less than about 0.002 inches, less than about 0.001 inches, less than about 0.0008 inches, or less than about 0.0005 inches. In yet another embodiment, a suitable filament may be circular and have a diameter in the range of thickness from about 0.0005 inches to about 0.015 inches, including exemplary values ​​of about 0.0006 inches, about 0.0007 inches, about 0.0008 inches, about 0.0009 inches, about 0.001 inches, about 0.002 inches, about 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches, about 0.009 inches, about 0.01 inches, about 0.012 inches, about 0.013 inches, and about 0.014 inches. In yet another embodiment, a suitable filament may be a flat filament having a height of less than about 0.006 inches, less than about 0.005 inches, less than about 0.004 inches, less than about 0.003 inches, less than about 0.001 inches, less than about 0.0009 inches, less than about 0.0008 inches, less than about 0.0007 inches, less than about 0.0006 inches, and less than about 0.0005 inches. In yet another embodiment, a flat filament may have a width of more than about 0.003 inches to about 0.015 inches, including exemplary values ​​of about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches, about 0.009 inches, about 0.01 inches, about 0.012 inches, about 0.013 inches, and about 0.014 inches. However, other geometric shapes and sizes are also suitable for specific embodiments.

[0285] In further embodiments, the braid may have a number of crosses (PICs) per inch of less than 50, less than 40, less than 30, less than 20, or less than 10. In yet another embodiment, the braid may have a PIC count of 10 to 2, including exemplary values ​​of 9, 8, 7, 6, 5, 4, and 3. In yet another embodiment, the PICs may vary along the longitudinal axis of the lumen. In yet another embodiment, the braid pattern may vary along the longitudinal axis of the lumen. In embodiments in which the braid includes filaments of nitinol, the nitinol has an expanded diameter d e It is heat-solidified in the process. In further embodiments in which the filament comprises stainless steel or nitinol, the filament is configured to be non-traumatic at least at the distal end of the sheath. Figures 9 to 23 illustrate partial elevation views of various structures of the braid 28. It is understood that the structure of the braid 28 may vary from section to section and may vary along the length of the sheath. It is further understood that the structures shown in Figures 9 to 23 are not necessarily drawn to a constant scale and only illustrate and non-limiting embodiments are shown. It is further understood that the braid is configured to provide torqueability of the sheath during insertion of the prosthesis. Again, it is understood that the presence of the braid in these embodiments is optional and embodiments having similar configurations without the presence of the braid are also disclosed.

[0286] As shown in Figures 61A and 61B, it is understood that the elongated tube 206 may contain any composition and may exhibit any of the properties disclosed herein.

[0287] Alternative embodiments of the sheath for introducing the prosthesis are also described. For example, Figures 62A and 62B illustrate cross-sectional views of the inner liners 500A and 500B of the sheath disclosed in non-consumable and consumable configurations (Figures 62A and 62B, respectively). When the prosthesis is introduced into the inner liner, the first edge 502 and the second edge 504 slide along the inner liner, with a stationary diameter d r From the expanded diameter d e The inner liner is extended to this extent, thereby shortening the overlapping portion 506 of the inner liner. eIt is understood that the sheath is configured to accommodate medical devices passing through a lumen. In a further embodiment, the sheath has a predetermined stationary diameter d after the medical device has passed through the lumen. r It contracts to that extent.

[0288] In certain embodiments, a certain amount of a first lubricant is placed between at least a portion of the inner liner and at least a portion of the outer layer comprising the braid and the disclosed elongated tubes. In yet another embodiment, a certain amount of a second lubricant is placed between at least a portion of the overlapping portion of the sheet and at least a portion of the sliding portion of the sheet. It is understood that the first and second lubricants may be the same or different. In certain and non-limiting embodiments, the first and / or second lubricants may include Christo Lube supplied by ECL or MED10 / 6670 supplied by Nusil. In yet another embodiment, it is understood that the amounts of the first and / or second lubricants may be readily determined by those skilled in the art.

[0289] In a further embodiment, the outer surface of the elongated tube defines at least a portion of the outer surface of the outer layer. In yet another embodiment, at least a portion of the inner surface of the elongated tube is at least partially bonded to at least a portion of the outer surface of the inner liner sheet. It is understood that the outer layer of the disclosed sheath is configured to provide hemostasis and prevent patient bleeding during the procedure.

[0290] Figures 63A to 63I illustrate other alternative embodiments of the sheath for introducing the prosthesis. Figure 63A shows a sheath 600A comprising an inner liner 602 having a first edge 602a and a second edge 602b, and an overlapping portion 602c, wherein the inner and outer surfaces of the inner liner overlap each other. The sheath 600A further comprises a certain amount of the second lubricant 608 disclosed herein, disposed between the sliding portion and the overlapping portion of the inner sheath. The sheath further comprises a braid 604 and an elongated tube 606. In this exemplary embodiment, the braid 604 is not embedded in the elongated tube 606. Figure 63B depicts an alternative embodiment of the sheath 600B in which a certain amount of the first lubricant 610 is applied between the inner liner and the outer layer comprising the braid 604 and the elongated tube 606. An additional embodiment of the sheath 600C is shown in Figure 63C. In this embodiment, the sheath 600C comprises an inner liner 602 having a first edge 602a and a second edge 602b, and a superimposed portion 602c, wherein the inner and outer surfaces of the inner liner overlap each other. The sheath further comprises a braid 604 and an elongated tube 606, which together can form the outer layer of the sheath. The sheath 600C further comprises a certain amount of the first lubricant 610 disclosed herein, disposed between the outer layer of the inner sheath and the inner liner. In this exemplary embodiment, the braid 604 is not embedded in the elongated tube 606. In the exemplary embodiment shown in Figure 63D, the exemplary sheath 600D comprises a braid 604 embedded within the elongated tube 606.

[0291] In further embodiments, the sheaths of the Disclosure may be provided with a hemostatic valve inside the lumen of the sheath at or near the proximal end of the sheath (not shown). In addition, exemplary sheaths disclosed herein may be provided with a soft tip at the distal end of the sheath (not shown). Such a soft tip may provide a lower hardness than the rest of the sheath. In some embodiments, the soft tip may have a Shore hardness of about 25D to about 40D, including exemplary values ​​of about 26D, about 27D, about 28D, about 29D, about 30D, about 31D, about 32D, about 33D, about 34D, about 35D, about 36D, about 37D, about 38D, and about 39D. In yet another embodiment, the soft tip may have a Shore hardness of about 25A to about 40A, including exemplary values ​​of about 26A, about 27A, about 28A, about 29A, about 30A, about 31A, about 32A, about 33A, about 34A, about 35A, about 36A, about 37A, about 38A, and about 39A.

[0292] In certain embodiments, the elongated tube and the inner liner may be joined together or otherwise physically linked to each other. It is understood that the amount of adhesion between the inner polymer liner 602 and the outer polymer layer comprising the braid 604 and the elongated tube 606 may be variable across the surface of the layer. The bonding between the layers may be created, for example, by thermal bonding. In certain embodiments, the bonding may be facilitated by the presence of an additional portion of the elastic polymer. For example, in certain embodiments, the sheath may comprise a first strip 611 of elastomer polymer positioned along at least a portion of the longitudinal axis of the lumen between at least a portion of the outer surface of the sheet without the overlapping portion 602c of the sheet and the inner surface of the elongated tube, as described herein and shown in Figures 63H-I. In such embodiments, the bonding between the elongated tube and the inner liner may be facilitated by the first strip of elastomer polymer. In yet another embodiment, the sheath may optionally further comprise a second strip 611 (Figures 63E-F) of elastomer polymer, if desired, positioned between at least a portion of the outer surface of the sheet at the proximal end of the sheath and the inner surface of the elongated tube. In yet another embodiment, the sheath may further comprise a third strip 611 (Figures 63E and 63G) of elastomer polymer, positioned between at least a portion of the outer surface of the sheet at the distal end of the sheath and the inner surface of the elongated tube. Again, in such embodiments, bonding between the elongated tube and the inner liner may be facilitated by the second and / or third strips of elastomer polymer.

[0293] Applications include expanded diameters d from approximately 3Fr to approximately 26Fr, with exemplary values ​​including approximately 5Fr, 8Fr, 10Fr, 12Fr, 15Fr, 18Fr, 20Fr, 22Fr, and 25Fr. e The resting diameter d of the lumen formed by the inner liner 602, which is expandable up to rA sheath of the present disclosure having the following characteristics can be utilized. The expanded diameter may vary slightly along the length of the disclosed sheath. For example, the expanded outer diameter at the proximal end of the sheath may range from about 3 Fr to about 28 Fr, including exemplary values ​​of about 5 Fr, about 8 Fr, about 10 Fr, about 12 Fr, about 15 Fr, about 18 Fr, about 20 Fr, about 22 Fr, and about 25 Fr, while the expanded outer diameter at the distal end of the sheath may range from about 3 Fr to about 25 Fr, including exemplary values ​​of about 8 Fr, about 10 Fr, about 12 Fr, about 15 Fr, about 18 Fr, about 20 Fr, and about 22 Fr. The disclosed sheath embodiments can expand to an expanded outer diameter approximately 10% larger than the original unexpanded outer diameter to approximately 100% larger than the original unexpanded outer diameter, including exemplary values ​​approximately 15% larger, approximately 20% larger, approximately 25% larger, approximately 30% larger, approximately 35% larger, approximately 40% larger, approximately 45% larger, approximately 50% larger, approximately 55% larger, approximately 60% larger, approximately 65% ​​larger, approximately 70% larger, approximately 75% larger, approximately 80% larger, approximately 85% larger, approximately 90% larger, and approximately 95% higher than the original unexpanded outer diameter.

[0294] As described above, it is understood that the disclosed sheath can be expanded from its resting position. The expansion of the disclosed sheath ranges from approximately 10% or less to approximately 430% or more of the resting diameter d r This can result in an expansion of the sheath. In certain embodiments, the expansion of the sheath results in a stationary diameter d r This can result in expansion of approximately 10% or less, approximately 9% or less, approximately 8% or less, approximately 7% or less, approximately 6% or less, approximately 5% or less, approximately 4% or less, approximately 3% or less, approximately 2% or less, and approximately 1% or less. In other embodiments, the expansion of the disclosed sheath is such that the stationary diameter d r This can result in expansion of approximately 10% or more, approximately 20% or more, approximately 30% or more, approximately 40% or more, approximately 50% or more, approximately 60% or more, approximately 70% or more, approximately 80% or more, approximately 90% or more, approximately 100% or more, approximately 125% or more, approximately 150% or more, approximately 175% or more, approximately 200% or more, approximately 225% or more, or approximately 250% or more.

[0295] Similar to previously disclosed embodiments, the embodiments illustrated in Figures 63A to 63D involve a wide variety of stationary diameters d r and outer diameter do It can be applied to a sheath having a diameter d of the outer diameter of the sheath. In some embodiments, the outer diameter d of the sheath is o The diameter gradually decreases from the proximal end of the sheath to the distal end of the sheath. For example, in one embodiment, the outer diameter d o The fr can gradually decrease from approximately 26 Fr at the proximal end to approximately 18 Fr at the distal end. (Sheath diameter d) o The transition may be gradual over substantially the entire length of the sheath. In other embodiments, the transition or reduction in the diameter of the sheath may occur only along a portion of the length of the sheath. For example, the transition may occur along the length from the proximal end to the distal end, and the length may range from about 0.5 inches to almost the entire length of the sheath, including any value between any two of the aforementioned values. In even further embodiments, d o The tapered section is minimal and constant along the section of the sheath passing through the vascular system. In such an embodiment, the tapered section is approximately 4 inches or less proximal to the sheath.

[0296] In some embodiments, the braid and / or elongated tubes may contain the same material or combination of materials along their entire length. In alternative embodiments, the material composition of each layer may vary along the length of the sheath. For example, an outer polymer tubular layer comprising both braid and elongated tubes may be provided with one or more segments, the composition of which varies by segment. For example, in one segment, the braid may contain nitinol having a different PIC number than another segment. In yet another exemplary embodiment, the elongated tubes in one segment may differ from the layers of elastic material in another segment. In yet another exemplary embodiment, one segment of the sheath may comprise a braid embedded in an elongated tube, while another segment may comprise a braid not embedded in an elongated tube. It is understood that the exemplary sheaths disclosed herein are not limiting. In certain exemplary embodiments, the sheath may comprise n segments, each of which may be the same or different. In further exemplary embodiments, the durometer grade of the outer layer composition may also vary along the length of the sheath such that the segment near the proximal end contains a more rigid material or combination of materials, while the segment near the distal end contains a more flexible material or combination of materials. This may allow for a sheath that has a relatively rigid proximal end at the point of introduction of the delivery device, while still having a relatively flexible distal end at the point of entry into the patient's blood vessel.

[0297] In addition, some embodiments of the sheaths disclosed herein may include an external hydrophilic coating on the outer surface of the elongated tube. Such a hydrophilic coating can facilitate the insertion of the sheath into the patient's blood vessels. Examples of suitable hydrophilic coatings include Harmony® Advanced Lubricity Coating and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM Medical Coating (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride) are also suitable for use with the sheath. This exemplary sheath, like other sheaths disclosed herein in some embodiments, may in some embodiments include a soft tip portion containing low-density polyethylene (LDPE) and may be configured to minimize trauma or damage to the patient's blood vessels as the sheath is navigated through the vascular system. The soft tip of this exemplary sheath can be formed using any of the materials described herein for the soft tip.

[0298] In certain embodiments, the exemplary sheaths described herein may also be generally represented as shown in Figure 35. In such exemplary embodiments, the sheaths described herein may have additional components as shown in Figures 35 and 36. However, it is understood that the sheaths disclosed herein do not need to have the components shown in Figures 35 and 36 and may be adapted for any other use. In such exemplary embodiments, this may be adapted to allow passage of any medical device requiring an introducer sheath.

[0299] Some exemplary embodiments of these additional sheaths are also shown in Figures 64A–64B and 65A–65B. Figures 64A–64B show cross-sectional views of exemplary sheaths obtained, for example, near the distal end. Figure 64A shows a sheath 1200A comprising an inner liner 1202 having a first edge 1202a and a second edge 1202b, and a superimposed portion 1202c, where the inner and outer surfaces of the inner liner overlap each other. The sheath 1200A further comprises a certain amount of a second lubricant 1208 disclosed herein, disposed between the sliding portion and the superimposed portion of the inner sheath. The sheath further comprises a braid 1204 and an elongated tube 1206. In this exemplary embodiment, the braid 1204 is not embedded in the layer of the elongated tube 1206. Figure 64B depicts an alternative embodiment of sheath 1200B in which a certain amount of the first lubricant 1210 is applied between the inner liner and the outer layer comprising the braid 1204 and the elongated tube 1206. An additional embodiment of sheath 1200C is shown in Figure 64C. In this embodiment, sheath 1200C comprises an inner liner 1202 having a first edge 1202a and a second edge 1202b, and an overlapping portion 1202c, the inner and outer surfaces of the inner liner overlapping each other. The sheath further comprises a braid 1204 and an elongated tube 1206, together forming the outer layer of the sheath. Sheath 1200C further includes a certain amount of the first lubricant 1210 disclosed herein, disposed between the outer layer of the inner sheath and the inner liner. In this exemplary embodiment, the braid 1204 is not embedded in the elongated tube 1206. In the exemplary embodiment shown in Figure 64D, the exemplary sheath 1200D comprises a braid 1204 embedded within an elongated tube 1206.

[0300] Figures 65A–D show cross-sectional views of the proximal section of the sheath. Figure 65A shows a sheath 1300A comprising an inner liner 1302 having a first edge 1302a and a second edge 1302b, and an overlay portion 1302c, where the inner and outer surfaces of the inner liner overlap each other. The sheath 1300A further comprises a certain amount of the second lubricant 1308 disclosed herein, disposed between the sliding portion and the overlay portion of the inner sheath. The sheath further comprises a braid 1304 and an elongated tube 1306. In this exemplary embodiment, the braid 1304 is not embedded in the elongated tube 1306. Figure 65B depicts an alternative embodiment of the sheath 1300B in which a certain amount of the first lubricant 1310 is applied between the inner liner and the outer layer comprising the braid 1304 and the elongated tube 1306. An additional embodiment of the sheath 1300C is shown in Figure 65C. In this embodiment, the sheath 1300C comprises an inner liner 1302 having a first edge 1302a and a second edge 1302b, and a superimposed portion 1302c, the inner and outer surfaces of the inner liner overlapping each other. The sheath further comprises a braid 1304 and an elongated tube 1306, both forming the outer layer of the sheath. The sheath 1300C further comprises a certain amount of the first lubricant 1310 disclosed herein, disposed between the outer layer of the inner sheath and the inner liner. In this exemplary embodiment, the braid 1304 is not embedded in the elongated tube 1306. In the exemplary embodiment shown in Figure 65D, the exemplary sheath 1300D comprises a braid 1304 embedded within the elongated tube 1306.

[0301] In further embodiments, as shown in Figure 66, the sheath 1400 is configured to expand from a stationary configuration to an expanded configuration shown in Figure 67, whether or not it has a braid embedded in an elongated tube (as shown in Figure 66) or a braid not embedded in a layer of elastomer polymer (not shown). In such embodiments, the first and second edges (1502a and 1502b) of the inner liner slide to shorten the length of the overlapping portion. In some exemplary embodiments, this movement may be facilitated by the presence of a first lubricant and / or a second lubricant, as disclosed above.

[0302] Refer to Figures 71-72 here. As disclosed herein, an elongated tube can be used as the outer jacket. The outer jacket 140 disclosed herein may comprise at least two polymer layers 146 and 147. In further embodiments, the outer jacket disclosed herein may include at least one intermediate reinforcing layer / member 145 located within the first polymer layer, within the second polymer layer, or between the first and second layers. Such an outer jacket may be placed on an additional optional polymer strip 1920, as shown and further described with reference to Figure 70.

[0303] Figures 73–77 illustrate an expandable outer jacket including a longitudinally extending reinforcing member 145. The outer jacket 140 may be used with any of the expandable sheaths described herein. The reinforcing member 145 prevents axial lumping of the outer jacket 140 during insertion into the patient's vascular system without sacrificing the low radial expansion force of the outer jacket 140. The reinforcing member 145 is typically constructed from a material that is more rigid than the main body portion of the outer jacket 140 (e.g., Pebax, polyurethane, nylon, or flat wire). The resistance of the reinforcing member 145 to stretching and / or compression prevents lumping / wrinkling of the outer jacket 140 during insertion, while still allowing the outer jacket 140 to expand radially.

[0304] The wall thickness of the outer jacket may range from 0.0040 inches to 0.0066 inches. In some embodiments, the thickness of the outer jacket is approximately 0.0055 inches. The wall thickness of the outer jacket 140 may remain constant along its entire length. However, in some embodiments, the thickness of the outer jacket 140 at the proximal end (T1) is greater than the thickness of the outer jacket 140 at the distal end (T2).

[0305] In further embodiments, the outer jacket 140 may comprise two or more reinforcing members 145. In such embodiments, the two or more reinforcing members 145 may be arranged as individual strips circumferentially within the first polymer layer, within the second polymer layer, or between the first and second layers at a predetermined distance from each other. Figure 75 is a cross-sectional view of the outer jacket 140 obtained along the cross-section BB of Figure 73. As provided in Figure 75, the outer jacket 140 includes three reinforcing members 145. In some embodiments, the outer jacket 140 includes only one reinforcing member 145 (Figure 77). In other embodiments, the outer jacket includes up to eight reinforcing members 145. When more than one reinforcing member 145 is used, the reinforcing members are evenly spaced around the circumference of the outer jacket 140. As further illustrated in Figure 75, the reinforcing members 145 may have a linear shape (e.g., a rectangle) in cross-section. However, any other regular or irregular shapes are also conceivable.

[0306] In a further embodiment, the reinforcing member 145 has a finite width smaller than the circumference of the outer jacket 140. The combined width (w) of the reinforcing members 145 may be in the range of 5% to 50% of the circumference of the outer jacket 140. In yet another embodiment, the combined width of the strips is about 5%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50% of the circumference of the elongated tube.

[0307] Figure 76 includes a partial view of the outer jacket 140 of Figure 75. As provided in Figure 76, the circumferential width of the reinforcing member 145 may range from 0.010 inches to 0.150 inches. In some embodiments, the distal end of the outer jacket 140 has a diameter of 0.200 inches, and the circumferential width of the reinforcing member 145 may range from 0.010 inches to 0.150 inches. In some exemplary and non-limiting embodiments, the diameter of the outer jacket at the distal end is approximately 0.200 inches, and the reinforcing members may have widths ranging from approximately 0.010 inches to approximately 0.150 inches, including exemplary values ​​of approximately 0.03 inches, approximately 0.035 inches, approximately 0.04 inches, approximately 0.045 inches, approximately 0.05 inches, approximately 0.055 inches, approximately 0.06 inches, approximately 0.065 inches, approximately 0.07 inches, approximately 0.075 inches, approximately 0.08 inches, approximately 0.085 inches, approximately 0.09 inches, approximately 0.095 inches, approximately 0.10 inches, approximately 0.105 inches, approximately 0.110 inches, approximately 0.115 inches, approximately 0.120 inches, approximately 0.125 inches, approximately 0.130 inches, approximately 0.135 inches, approximately 0.140 inches, and approximately 0.145 inches. The widths shown above are illustrative, and it should be understood that if the distal outer diameter of the elongated sheath is of a different size than 0.200 inches, the strip width may be adjusted by the same or a different ratio. Furthermore, in a further embodiment, as described above, the width of the reinforcing member may be measured as a ratio of the circumference of the elongated tube.

[0308] In embodiments where the reinforcing member 145 exists as one or more strips arranged circumferentially along the length of the outer jacket 140, it is further understood that the width of the reinforcing member 145 may be the same along the length or may vary along the length. In embodiments where the width of the reinforcing member 145 varies along the length of the outer jacket 140, such a reinforcing member 145 may have any of the width values ​​disclosed above.

[0309] In further embodiments, at least one reinforcing member 145 is configured to provide axial reinforcement to the outer jacket 140, and consequently to the sheath through which the outer jacket 140 may be used. In such exemplary embodiments, at least one reinforcing member 145 may be positioned along the length of the outer jacket 140, or along a portion of the length of the outer jacket 140. In some embodiments, at least one reinforcing member 145 is positioned at the distal and / or proximal end of the outer jacket 140, or as part of the length of the outer jacket 140. In yet another embodiment, the reinforcing member 145 may also be positioned at any location along the length of the outer jacket 140.

[0310] As described above and illustrated in Figure 75, the outer jacket 140 has a two-layer structure, namely an inner layer (first polymer layer) 146 and an outer layer (second polymer layer) 147, wherein the outer layer provides abrasion resistance (e.g., between the sheath and calcific lesions) and better resistance to hydrophilic coating processes, and the inner layer is a more lubricating material (e.g., to prevent the outer jacket from adhering to the outer layer of the sheath during expansion), providing higher pressure resistance or expansion resistance and hemostasis. In some embodiments, the inner layer 146 (first polymer layer) forms the inner surface of the outer jacket 140, the outer layer 147 (second polymer layer) forms the outer surface of the outer jacket, and a reinforcing member 145 is positioned between the outer surface of the inner layer (inner liner) 146 and the inner surface of the outer layer 147.

[0311] In some embodiments, the inner layer 146 may be composed of Pebax or polyurethane having a Shore A durometer of 25D to 35D. In some embodiments, the inner layer 146 includes PTFE powder, an optional inorganic filler, and an optional tackiness-reducing additive to reduce friction as the outer layer 108 of the sheath expands by sliding against the outer jacket 140. In some embodiments, the outer layer 147 of the outer jacket 140 is composed of polyurethane or polyurethane / styrene block copolymer (SBC) having a Shore A durometer lower than about 60, for example, Neusoft 597-50A having a Shore A hardness of about 55A. In certain embodiments, the inner layer 146 is constructed from a polyether block amide such as Pebax having a Shore D durometer of less than about 35.

[0312] As provided in Figures 75 and 76, the reinforcing member 145 is at least partially embedded in the inner layer 146. In some embodiments, the thickness of the reinforcing member 145 is less than the thickness of the inner layer 146. For example, as shown in Figure 76, the reinforcing member 145 has a thickness in the range of 0.0005 inches to 0.0015 inches. In some embodiments, the reinforcing member 145 has a thickness of about 0.001 inches. In an exemplary configuration, the reinforcing member 145 has a thickness of 0.001 inches, and the inner layer has a thickness of 0.00154 inches. In another embodiment not shown, the reinforcing member 145 has a thickness corresponding to the thickness of the inner layer 146. In further embodiments, the reinforcing member 145 has a thickness greater than the thickness of the inner layer 146. In some embodiments, the inner layer 146 and the reinforcing member 145 are co-extruded. Similarly, the inner layer 146, the reinforcing member 145, and the outer layer 147 are co-extruded with the reinforcing member 145 positioned between the inner and outer layers 146, 147. In other embodiments, the inner layer 146 is provided across the reinforcing member 145, and the two components are joined or fused together by at least one of heat or compression.

[0313] As described above, the reinforcing member 145 is constructed from a material that is more rigid than the main body portion of the outer jacket 140 (inner layer 146, outer layer 147) and has a low coefficient of friction (e.g., high-density polyethylene). In some embodiments, the reinforcing member 145 is constructed from a polymer that conforms to the inner and outer layers, for example, high-durometer Pebax or polyurethane. The reinforcing member 145 may also be constructed from a material having a Shore D durometer in the range of 45D to 76D.

[0314] Additional embodiments of sheaths that may be used with the elongated tubes disclosed herein can be found in U.S. Patent Application No. 63 / 021,945, which is incorporated herein in whole.

[0315] The sheaths disclosed herein may be configured to expand locally at specific locations corresponding to the location of a medical device along the length of the lumen, and then to contract locally after the medical device has passed that specific location. Thus, as the medical device is introduced through the sheath, bulges may be visible that advance longitudinally along the length of the sheath, and as the device advances along the length of the sheath, bulges representing continuous local expansion and contraction may be visible. In some embodiments, each segment of the sheath is the original resting diameter d of the lumen. r To regain its original shape, it can be locally contracted after any radially outward (insertive) force has been removed.

[0316] In some examples, each segment of the sheath is the original resting diameter of the lumen d r It can be locally contracted after any radially outward force is removed, so as to return at least partially to its original state.

[0317] method An example of a method for fabricating a sheath is as follows. These steps are not intended to be limiting. The listed steps can be rearranged as needed. Other steps can be added, or some steps may not be necessary in other embodiments.

[0318] Disclosed herein is a method for producing a sheath having a proximal and distal end, a) extruding a tubular body to form an elongated tube comprising a first polymer layer, the first polymer layer comprising a first composite composition comprising a polymer comprising more than 0% by weight and less than 100% by weight of polyether block amide, polyurethane, or a combination thereof, less than about 65% by weight of an inorganic filler based on the total weight of the first composite composition, and up to about 20% by weight of a solid lubricant filler based on the total weight of the first composite composition, and b) arranging an elongated tube on a sheath such that the elongated tube forms an outer layer of the sheath, the elongated tube being positioned at least at the proximal end of the sheath and extending along at least a portion of the length of the sheath, the elongated tube changing from an initial diameter d0 in a non-expanded position to an expanded diameter d in an expanded position when a medical device passes through. e A method comprising positioning a sheath configured to expand reversibly to a certain extent, wherein the formed sheath exhibits at least a 10% reduction in insertion force compared to a substantially identical reference sheath without a first polymer layer.

[0319] It is understood that any method known in the art may be used to form a composition of an elongated tube. In certain embodiments, the components present in the elongated tube are provided to form a compound. The compound is then mixed to form a substantially homogeneous mixture. Moreover, in other embodiments, the mixture is homogeneous. In yet another embodiment, the mixture is extruded to form an elongated tube having a first polymer layer. The formed first polymer layer may contain any (and any combination thereof) of the compositions and properties disclosed above.

[0320] In further embodiments, the method also includes the step of forming an elongated tube comprising two or more layers, as disclosed above. In such embodiments, for example, when the elongated tube comprises either the first polymer layer and the second polymer layer disclosed above, such layers can be co-extruded to form the disclosed elongated tube. The desired elongated tube can be obtained using any extrusion equipment known in the art.

[0321] The method disclosed herein produces one of the elongated tubes disclosed above.

[0322] In further embodiments, methods for forming additional portions of the sheath are also disclosed. In certain embodiments, an elongated tube can act as the outer jacket of the sheath. On the other hand, in other embodiments, the elongated tube can form the outer layer of the sheath in which there is no additional outer jacket.

[0323] For example, but not limited to, the inner layer 108 may be formed to include a first fold and a second fold, as shown in one of the exemplary sheaths, and an overlapping folded portion 118 extending circumferentially between the first and second folds. The overlapping folded portion 118 may be formed to include a radial overlap of at least two thicknesses of the inner layer 108. The inner layer 108 may be extruded to include the folded portion 118. Alternatively, the folded portion 118 may be formed after the inner layer 108 has been extruded (for example, formed on a cylindrical tubular structure).

[0324] A discontinuous outer layer 110 can be further provided around the inner layer 108 (at least partially). The outer layer 110 is formed to include the overlapping portion 120 and the lower portion 122 such that at least a portion of the folded portion 118 of the inner layer 108 is positioned between the overlapping portion 122 and the lower portion 122. In some embodiments, the inner layer 108 and the outer layer 110 are co-extruded. In alternative embodiments, the inner layer 108 and the outer layer 110 are formed separately and joined together.

[0325] To bond the inner layer 108 to the outer layer 110 (at least partially), an adhesive layer 128 can be provided between the inner layer 108 and the outer layer 110. The adhesive layer 128 can be applied axially along the length of the sheath, for example, along a portion of the total length of the sheath, or along the total length of the sheath, to the inner and outer layers 108, 110 to bond them together. In one embodiment, the adhesive layer 128 is co-extruded with the outer layer 110. In a further embodiment, the adhesive layer 130 is co-extruded with the inner layer 108. In an alternative exemplary method, an adhesive layer 142 may be applied to the outer surface of the inner liner 108 and / or the inner surface of the outer layer 110.

[0326] After the adhesive layer 128 is applied to desired locations along the inner and / or outer layer 110, the outer layer 110 is applied across the inner layer 108. The outer layer 110 can then be bonded to the inner layer 108 by heat-curing the adhesive layer 128. The adhesive layer 128 may contain a material that can be cured at temperatures above room temperature, in which case heat treatment may be applied to the assembled inner layer 108 / outer layer 110. The adhesive layer 128 may also consist of a material that cures at room temperature. Thus, after applying the adhesive layer 128 (at a temperature below room temperature) and assembling the outer layer 110 across the inner layer 108, the temperature of the combined layers may be raised to room temperature.

[0327] As illustrated in Figure 56, the lubricant 142 can be selectively applied to desired locations along the length of the outer layer 110 and / or outer jacket (the elongated tube described) 140. It is understood that the elongated tube 140 can be formed by any of the methods disclosed above.

[0328] As described above, the lubricant 142 may be provided on the outer surface of the outer layer 110 adjacent to the longitudinally extending edge 126 of the overlapping portion 120, on any portion of the folded portion 118 extending / projecting beyond the edge 126, and / or on any portion of the outer surface of the outer layer 110 adjacent to the projecting portion of the folded portion 118. The lubricant 142 may be provided as a band extending around a portion of the circumference of the outer layer, and also as a band of lubricant 142 extending longitudinally along the length of the outer layer 110. After the lubricant 142 has been selectively applied to the outer surface of the outer layer 110, the outer jacket 140 may be applied across the outer layer 110. As outlined above, the lubricant 142 may include a thermosetting material, in which case a heat treatment may be applied to the outer layer 110 / elongated tube 140. The lubricant 142 may also consist of a material that hardens at room temperature. Therefore, after application of the lubricant 142 (at a temperature below room temperature), the temperature of the outer layer 110 can be raised to room temperature (either separately or in combination with the outer jacket (elongated tube) 140).

[0329] Next, the outer jacket 140 formed by any of the methods disclosed above may be applied over / around the outer layer 110 and bonded to the outer layer 110 at at least one of the proximal and distal ends of the outer layer 110. The outer jacket 140 may also be bonded to the outer layer 110 along its length. The outer jacket 140 may be bonded to the outer layer 110 via a heat treatment process, for example, a reflow process in which the outer layer 110 and the outer jacket 140 are at least partially m...

Claims

[Claim 1] A method for manufacturing a sheath having a proximal end and a distal end, a) A step of extruding a tubular body to form an elongated tube having a first polymer layer, wherein the first polymer layer comprises a first composite composition comprising, based on the total weight of the first composite composition, a polymer comprising more than 0% to less than 100% of polyether block amide, polyurethane, or a combination thereof; based on the total weight of the first composite composition, less than about 65% of an inorganic filler; and based on the total weight of the first composite composition, up to about 20% of a solid lubricant filler. b) A step of arranging an elongated tube on the sheath such that the elongated tube forms the outer layer of the sheath, wherein the elongated tube is positioned at least at the proximal end of the sheath, extends along at least a portion of the length of the sheath, and is configured to reversibly expand from an initial diameter in a non-expanded position to an expanded diameter in an expanded position when a medical device passes through, In the method comprising, A method wherein the formed sheath exhibits at least a 10% reduction in insertion force compared to a substantially identical reference sheath without the first polymer layer.

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