Expandable sheath for introducing an intravascular delivery device into the body - Patents.com

Abstract

Embodiments of the expandable sheath may be used in conjunction with a catheter assembly to introduce a prosthesis, such as a heart valve, into a patient. Such embodiments may minimize trauma to the vessel by allowing temporary expansion of a portion of the introducer sheath to accommodate a delivery device, followed by return to the original diameter once the prosthesis has passed. Some embodiments may include a sheath having a tubular inner liner wound in a helical scroll slidable configuration. The disclosed sheath is configured to expand from a predetermined resting diameter dT to an expanded diameter de during application of a radially outward force by passage of a medical device through the sheath.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 209,337, filed June 10, 2021, U.S. Provisional Application No. 63 / 214,605, filed June 24, 2021, U.S. Provisional Application No. 63 / 214,349, filed June 24, 2021, and U.S. Provisional Application No. 63 / 323,429, filed March 24, 2022, the entire contents of which are incorporated herein by reference. Field

[0002] The present application relates to aspects of a sheath for use with catheter-based techniques 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 [Background technology]

[0003] Intravascular delivery catheter assemblies are used to implant prosthetic devices, such as artificial valves, at locations inside the body that are not easily accessible by surgery or where access without invasive surgery is desirable. For example, aortic, mitral, tricuspid, and / or pulmonary prosthetic valves can be delivered to a treatment site using minimally invasive surgical techniques.

[0004] An introducer sheath can be used to safely introduce a delivery device into a patient's vasculature (e.g., the femoral artery). The introducer sheath generally has an elongated sleeve that is inserted into the vasculature and a housing that includes one or more sealing valves that allow the delivery device to be placed in fluid communication with the vasculature with minimal blood loss. Conventional introducer sheaths typically require a tubular loader to be inserted through a seal in the housing to provide an unobstructed path through the housing for a valve mounted on the balloon catheter. Conventional loaders extend from the proximal end of the introducer sheath, thus reducing the available working length of the delivery device that can be inserted into the body through the sheath.

[0005] Conventional methods of accessing a blood vessel, such as the femoral artery, prior to introducing a delivery system include dilating the vessel using multiple dilators or sheaths of progressively increasing diameter. This repeated insertion and dilation of the vessel can increase the amount of time the procedure takes, as well as the risk of damage to the vessel.

[0006] Radially expanding intravascular sheaths have been disclosed, and such sheaths tend to have complex mechanisms, such as ratcheting mechanisms, that maintain the shaft or sheath in an expanded configuration upon the introduction of an instrument having a diameter larger than the original diameter of the sheath.

[0007] However, delivery and / or removal of prostheses and other materials to or from a patient still poses significant risks to the patient. Furthermore, accessing the blood vessel remains a challenge due to the relatively large profile of the delivery system, which can cause longitudinal and radial laceration of the vessel during insertion. The delivery system may additionally ablate calcified plaque within the vessel, posing an additional risk of thrombosis caused by the ablated plaque.

[0008] Thus, there remains a need in the art for improved introducer sheaths for endovascular systems used to implant valves and other prosthetic devices. overview Summary of the Invention

[0009] In certain aspects, disclosed herein are expandable sheaths that can minimize trauma to the vessel by allowing temporary expansion of a portion of the introducer sheath to accommodate the delivery system, and then returning to its original diameter once the delivery system has passed. Aspects of the present disclosure are directed to sheaths that have a smaller profile than that of prior art introducer sheaths. It is understood that in certain aspects, the use of the sheaths disclosed herein can reduce the length of time the procedure takes and reduce the risk of longitudinal or radial vessel laceration or plaque detachment, since only one sheath is required, rather than several different sizes of sheaths. In further aspects, the introduction of the expandable sheaths disclosed herein requires only a single vessel insertion, as opposed to multiple insertions required for vessel expansion.

[0010] Aspects of the present disclosure are directed to a sheath for introducing a prosthesis, which may include an inner liner and an outer layer, at least a portion of the sheath may be designed or configured to locally expand from a first diameter (resting diameter) to a second diameter (expanded diameter) when the prosthesis is pushed through the lumen of the sheath, and then at least partially return to the first diameter once the prosthesis has passed.

[0011] Also disclosed herein is a sheath for delivering a medical device, the sheath having a proximal end and a distal end, comprising a tubular inner liner having a longitudinal slit extending along a length of the tubular inner liner such that the tubular inner liner is wound in a spiral scroll configuration, the longitudinal slit forming a first longitudinal edge and a second longitudinal edge of the tubular inner liner, and in the spiral scroll configuration, at least a portion of an inner surface of the inner liner helically overlaps at least a portion of an outer surface of the inner liner, and the inner liner is wound in a spiral scroll configuration. a first longitudinal edge of the inner liner is slidable along at least a portion of an inner surface of the inner liner and a second longitudinal edge is slidable along at least a portion of an outer surface of the inner liner, the inner surface of the tubular inner liner defining a lumen of the sheath, the tubular inner liner being configured to rotate to a static diameter d by causing the first edge of the inner liner to slide helically along at least a portion of the inner surface and the second edge of the inner liner to slide helically along at least a portion of the outer surface of the inner liner during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r From expansion diameter d e The sheath is configured to expand.

[0012] In yet a further aspect, the tubular liner of the disclosed sheath is configured to expand without substantially having a gap formed between a first longitudinal edge and a second longitudinal edge of the tubular inner liner, while in still a further aspect, the tubular inner liner of the disclosed sheath is further configured to flex while passing through a patient's natural anatomy without forming a gap between the first longitudinal edge and the second longitudinal edge of the tubular inner liner.

[0013] In yet a further aspect, the longitudinal slit of the tubular inner liner extends from the proximal end of the tubular inner liner to the distal end of the tubular inner liner in a direction offset from the longitudinal axis of the tubular inner liner. In yet a further aspect, the helical configuration of the tubular inner liner can have a predetermined pitch.

[0014] In still further aspects, the sheaths disclosed herein can further comprise an outer layer. In these exemplary non-limiting aspects, the outer layer can comprise one or more layers.

[0015] Also disclosed herein is a method of making a sheath having a proximal end and a distal end, the method comprising: forming a tubular inner liner, the method including: i) forming a longitudinal slit by cutting a circumference of an elongated, single lumen tube between a proximal end and a distal end of the elongated, single lumen tube in a direction offset from a longitudinal axis of the elongated, single lumen tube such that a first longitudinal edge and a second longitudinal edge are formed; and ii) forming a longitudinal slit such that at least a portion of an inner surface of the inner liner helically overlaps at least a portion of an outer surface of the inner liner, the longitudinal slit being offset from a longitudinal axis of the elongated, single lumen tube such that a first longitudinal edge and a second longitudinal edge are formed. the first longitudinal edge is slidable along at least a portion of the inner surface of the inner liner and the second longitudinal edge is slidable along at least a portion of the outer surface of the inner liner, the inner surface of the tubular inner liner defining the lumen of the sheath, the tubular inner liner being configured to rotate to a static diameter d by causing the first edge of the inner liner to slide helically along at least a portion of the inner surface and the second edge of the inner liner to slide helically along at least a portion of the outer surface of the inner liner during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r From expansion diameter d e and forming a tubular inner liner having a spiral scroll configuration by winding an elongated single lumen tube having a longitudinal slit therein such that the tubular inner liner is configured to expand into a spiral scroll configuration.

[0016] In yet a further aspect, the winding step includes positioning an elongated single lumen tube having a longitudinal slit over a mandrel having a predetermined diameter to form a helical configuration, the predetermined diameter of the mandrel being in agreement with a stationary d rIn yet a further aspect, the formed tubular inner liner is configured to expand without having a gap formed between a first longitudinal edge and a second longitudinal edge of the tubular inner liner, while in a still further aspect, the formed tubular inner liner is configured to flex while passing through a patient's natural anatomy without forming a gap between a first longitudinal edge and a second longitudinal edge of the tubular inner liner.

[0017] In still further aspects, the methods disclosed herein further include disposing an outer layer on at least a portion of the outer surface of the inner liner. Meanwhile, in still further exemplary aspects, the methods disclosed herein may include disposing a braided layer on at least a portion of the outer surface of the tubular inner layer prior to disposing the outer layer. In still further aspects, the methods may also include disposing the outer layer on the braided layer and at least partially embedding the braided layer within the outer layer. In still further aspects, the methods may also include disposing a lubricant on at least a portion of the outer surface of the inner liner prior to disposing the outer layer. In such exemplary aspects, the methods may include disposing a lubricant on at least a portion of the outer surface of the inner liner prior to disposing the braided layer or after disposing the braided layer.

[0018] Also disclosed herein is a method of delivering a prosthesis to a treatment site, the method including at least partially inserting an expandable sheath into a patient's vasculature, the expandable sheath being as described in any embodiment herein; locally expanding a tubular liner during passage of the prosthesis by sliding first and second longitudinal edges together; and locally collapsing the sheath from the locally expanded state back to an at least partially unexpanded state after passage of the prosthesis.

[0019] Additionally or alternatively, the medical device may be a prosthetic heart valve mounted in a radially crimped state on the delivery device, and the act of advancing the medical device through the sheath includes advancing the delivery device and the prosthetic heart valve into the patient's vascular system.

[0020] The foregoing and other features and advantages of the present disclosure will become more apparent from the following detailed description, which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an elevational view of a sheath in accordance with the present disclosure along with an endovascular delivery device for implanting a prosthetic valve. [Figure 2A] FIG. 2A is a cross-sectional view of an embodiment of a sheath for introducing a prosthesis into a patient. [Figure 2B] FIG. 2B is a cross-sectional view of an embodiment of a sheath for introducing a prosthesis into a patient. [Figure 2C] FIG. 2C is a perspective view of one component of such a sheath. [Figure 3A] FIG. 3A is an elevational view of an embodiment of a sheath according to the present disclosure having uniform and varying resting diameters dr. [Figure 3B] FIG. 3B is an elevational view of an embodiment of a sheath according to the present disclosure having uniform and varying resting diameters dr. [Figure 3C] FIG. 3C is an elevational view of an embodiment of a sheath according to the present disclosure having uniform and varying resting diameters dr. [Figure 4A] FIG. 4A shows a partial elevational view of an exemplary embodiment of a braided structure with various PICs according to the present disclosure. [Figure 4B] FIG. 4B shows a partial elevational view of an exemplary embodiment of a braided structure with various PICs according to the present disclosure. [Figure 4C] FIG. 4C shows a partial elevational view of an exemplary embodiment of a braided structure with various PICs according to the present disclosure. [Figure 4D] FIG. 4D shows a partial elevational view of an exemplary embodiment of a braided structure with various PICs according to the present disclosure. [Figure 5A] FIG. 5A illustrates a cross-sectional view of one embodiment of an exemplary inner liner, depicting the unexpanded configuration. [Figure 5B] FIG. 5B illustrates a cross-sectional view of one embodiment of an exemplary inner liner, depicting the expanded configuration. [Figure 6A] FIG. 6A shows a cross-sectional view of an exemplary embodiment of a sheath. [Figure 6B] FIG. 6B shows a cross-sectional view of an exemplary embodiment of a sheath. [Figure 6C] FIG. 6C shows a cross-sectional view of an exemplary embodiment of a sheath. [Figure 6D] FIG. 6D shows a cross-sectional view of an exemplary embodiment of a sheath. [Figure 6E] FIG. 6E shows a cross-sectional view of an exemplary embodiment of a sheath. [Figure 6F] FIG. 6F shows a perspective view of an exemplary embodiment of a sheath. [Figure 6G] FIG. 6G shows a perspective view of an exemplary sheath embodiment. [Figure 6H] FIG. 6H shows a cross-sectional view of an exemplary embodiment of a sheath. [Figure 6I] FIG. 6I shows a perspective view of an exemplary sheath embodiment. [Figure 7] FIG. 7 illustrates a block diagram of one embodiment of a method of making a sheath according to the present disclosure. [Figure 8] FIG. 8 illustrates a block diagram of another embodiment of a method of making a sheath according to the present disclosure. [Figure 9A] FIG. 9A illustrates a cross-sectional or side view of the method steps of the method shown in FIGS. [Figure 9B] FIG. 9B illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9C] FIG. 9C illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9D] FIG. 9D illustrates a cross-sectional or side view of the method steps of the method shown in FIGS. [Figure 9E] FIG. 9E illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9F] FIG. 9F illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9G] FIG. 9G illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9H] FIG. 9H illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9I] FIG. 9I illustrates a cross-sectional or side view of the method steps of the method shown in FIGS. [Figure 9J] FIG. 9J illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 9K] FIG. 9K illustrates a cross-sectional or side view of the method step of the method shown in FIGS. [Figure 10] FIG. 10 is an elevational view of an expandable sheath and an exemplary housing according to the present disclosure. [Figure 11] FIG. 11 is an enlarged cutaway view of the distal end of the sheath of FIG. [Figure 12A] 12A is a cross-sectional view of the distal end of the exemplary sheath of FIG. 14 taken along line 37-37 of FIG. [Figure 12B] 12B is a cross-sectional view of the distal end of the exemplary sheath of FIG. 14 taken along line 37-37 of FIG. [Figure 12C] 12C is a cross-sectional view of the distal end of the exemplary sheath of FIG. 14 taken along line 37-37 of FIG. [Figure 12D] 12D is a cross-sectional view of the distal end of the exemplary sheath of FIG. 14 taken along line 37-37 of FIG. [Figure 13A] 13A is a cross-sectional view of the proximal section of the sheath of FIG. 10 taken along line 38-38 of FIG. [Figure 13B] 13B is a cross-sectional view of the proximal section of the sheath of FIG. 10 taken along line 38-38 of FIG. [Figure 13C] 13C is a cross-sectional view of the proximal section of the sheath of FIG. 10 taken along line 38-38 of FIG. [Figure 13D] 13D is a cross-sectional view of the proximal section of the sheath of FIG. 10 taken along line 38-38 of FIG. [Figure 14] 14 is a cross-sectional view of the sheath of FIG. 10 in a resting (unexpanded) configuration taken along line 39-39 of FIG. [Figure 15] FIG. 15 shows a cross-sectional view of the sheath of FIG. 14 in an expanded configuration. [Figure 16] FIG. 16 shows experimental data for an exemplary sheath in one embodiment. [Figure 17] FIG. 17 shows experimental data for an exemplary sheath in another embodiment. [Figure 18] FIG. 18 illustrates an exemplary inner liner of a sheath in one embodiment in a collapsed and unexpanded configuration. [Figure 19] FIG. 19 illustrates a cross-sectional view of an exemplary sheath in one embodiment showing the inner liner and outer layer shown in FIG. [Figure 20A] FIG. 20A illustrates an exemplary manufacturing process for the inner liner shown in FIG. [Figure 20B] FIG. 20B illustrates an exemplary manufacturing process for the inner liner shown in FIG. [Figure 20C] FIG. 20C illustrates an exemplary manufacturing process for the inner liner shown in FIG. [Figure 21A] FIG. 21A illustrates an exemplary sheath in one embodiment showing the inner liner and outer layer in a collapsed and unexpanded configuration, showing a cross-sectional schematic of the sheath. [Figure 21B] FIG. 21B illustrates an exemplary sheath in one embodiment showing the inner liner and outer layer in a collapsed and unexpanded configuration, showing a schematic side view of the sheath. [Figure 22A] FIG. 22A illustrates an exemplary sheath according to one embodiment, showing a schematic diagram of a cross-section of the sheath in a collapsed configuration (left) and an expanded configuration (right). [Figure 22B] FIG. 22B illustrates an exemplary sheath according to one embodiment, showing a snapshot of the exemplary sheath expanding during passage of a medical device. [Figure 23]FIG. 23 shows a schematic cross-sectional view of an exemplary sheath according to one embodiment. [Figure 24A] FIG. 24A shows a schematic cross-sectional view of an exemplary sheath according to one embodiment. [Figure 24B] FIG. 24B shows a schematic cross-sectional view of an exemplary sheath according to one embodiment. [Figure 25A] FIG. 25A illustrates the combination of various inner liners on an exemplary sheath, showing cross-sectional views of the various liners prior to forming the exemplary inner liner. [Figure 25B] FIG. 25B illustrates the combination of various inner liners with an exemplary sheath, showing cross-sectional views of the various liners prior to forming the exemplary inner liner. [Figure 25C] FIG. 25C illustrates the combination of various inner liners with an exemplary sheath, showing cross-sectional views of the various liners prior to forming the exemplary inner liner. [Figure 25D] FIG. 25D illustrates the combination of various inner liners with an exemplary sheath, showing cross-sectional views of the various liners prior to forming the exemplary inner liner. [Figure 25E] FIG. 25E illustrates various inner liner combinations of an exemplary sheath, showing various cross-sectional views of an exemplary inner liner in a spiral configuration. [Figure 25F] FIG. 25F illustrates various inner liner combinations of an exemplary sheath, showing various cross-sectional views of an exemplary inner liner in a spiral configuration. [Figure 25G] FIG. 25G illustrates various inner liner combinations of an exemplary sheath, showing various cross-sectional views of an exemplary inner liner in a spiral configuration. [Fig. 25H] FIG. 25H illustrates various inner liner combinations of an exemplary sheath, showing various cross-sectional views of an exemplary inner liner in a spiral configuration. [Figure 26] FIG. 26 illustrates a side view of an exemplary lubricant pattern disposed on an exemplary inner liner according to one embodiment. [Figure 27A]FIG. 27A shows a cross-sectional view of an exemplary sheath in a folded configuration (FIG. 27A) with a bond between the inner and outer liners. [Figure 27B] FIG. 27B illustrates a cross-sectional view of an exemplary sheath in an expanded configuration (FIG. 27B) with a bond between the inner and outer liners. [Figure 28A] FIG. 28A illustrates various methods of forming a bond between the inner liner and the outer layer of an exemplary sheath. [Figure 28B] FIG. 28B illustrates various methods of forming a bond between the inner liner and the outer layer of an exemplary sheath. [Figure 28C] FIG. 28C illustrates various methods of forming a bond between the inner liner and the outer layer of an exemplary sheath. [Figure 29A] FIG. 29A shows a schematic diagram of the reinforcing jacket effect (FIGS. 25A-25D) and the ballooning guard effect (FIGS. 25A-25B and 25E-25F) on the patient's anatomy. [Figure 29B] FIG. 29B shows a schematic diagram of the reinforcing jacket effect (FIGS. 25A-25D) and the ballooning guard effect (FIGS. 25A-25B and 25E-25F) on the patient's anatomy. [Figure 29C] FIG. 29C shows a schematic diagram of the reinforcing jacket effect (FIGS. 25A-25D) and ballooning guard effect (FIGS. 25A-25B and 25E-25F) on the patient's anatomy. [Figure 29D] FIG. 29D shows a schematic diagram of the reinforcing jacket effect (FIGS. 25A-25D) and ballooning guard effect (FIGS. 25A-25B and 25E-25F) on the patient's anatomy. [Figure 29E] FIG. 29E shows a schematic diagram of the reinforcing jacket effect (FIGS. 25A-25D) and ballooning guard effect (FIGS. 25A-25B and 25E-25F) on the patient's anatomy. [Figure 29F] FIG. 29F shows a schematic diagram of the reinforcing jacket effect (FIGS. 25A-25D) and ballooning guard effect (FIGS. 25A-25B and 25E-25F) on the patient's anatomy. [Figure 30A] FIG. 30A shows a schematic diagram of a reinforcing jacket present within an exemplary sheath, according to one embodiment. [Figure 30B] FIG. 30B shows a schematic diagram of a reinforcing jacket present within an exemplary sheath, according to one embodiment. [Diagram 31] FIG. 31 illustrates a method of making an exemplary sheath in one embodiment. [Diagram 32] FIG. 32 illustrates an exemplary sheath in one embodiment. [Diagram 33] FIG. 33 illustrates an exemplary sheath in one embodiment. [Diagram 34] FIG. 34 illustrates an exemplary sheath in one embodiment. [Diagram 35] FIG. 35 is a cross-sectional view of an exemplary sheath according to another embodiment. [Diagram 36] FIG. 36 is a cross-sectional view of an exemplary sheath according to another embodiment. [Figure 37] FIG. 37 is an elevational view of an exemplary outer layer according to another embodiment. [Figure 38] FIG. 38 is a cross-sectional view of an exemplary elongated tube taken along section line AA of FIG. [Figure 39] FIG. 39 is a cross-sectional view of an exemplary outer layer in a resting (unexpanded) configuration taken along section line BB of FIG. [Diagram 40] FIG. 40 is a partial cross-sectional view of an exemplary outer layer according to one embodiment. [Diagram 41] 41 is a cross-sectional view of another exemplary outer layer in a resting (unexpanded) configuration including a single reinforcing member taken along section line BB of FIG. [Figure 42A] FIG. 42A shows an exemplary sheath having a two-layer structure in one embodiment. [Figure 42B] FIG. 42B illustrates an exemplary sheath having a two-layer structure in one embodiment. [Figure 42C] FIG. 42C illustrates an exemplary sheath having a two-layer structure in one embodiment. [Figure 43A] FIG. 43A shows an exemplary sheath having at least one bond site on the inner surface of the outer layer, according to one embodiment. [Figure 43B] FIG. 43B illustrates an exemplary sheath having at least one bond site on the inner surface of the outer layer, according to one embodiment. [Diagram 44] FIG. 44 is a side elevational view of an exemplary sheath having proximal and distal sections in an unexpanded configuration. [Diagram 45] FIG. 45 is a perspective view of a distal section of the sheath of FIG. 44 in an unexpanded configuration. [Figure 46] FIG. 46 is another perspective view of the exemplary sheath of FIG. 44 with the tip section in an expanded configuration. [Figure 47] FIG. 47 is a side elevational view of the distal section of the sheath of FIG. 44 in a split configuration. [Figure 48] FIG. 48 is a perspective view of a distal section of the sheath of FIG. 44 in a split configuration. [Figure 49] FIG. 49 is a plan view of an inner liner layer having cuts for forming into a tip section. [Figure 50] FIG. 50 is a perspective view of the inner liner layer of FIG. 49 in a rolled configuration. [Figure 51] FIG. 51 is a top plan view of the inner liner layer of FIG. [Figure 52] 52 is an enlarged view of a portion of the inner liner layer of FIG. [Figure 53] FIG. 53 is a plan view of the inner liner layer with additional sections removed to form the tip section. [Figure 54] FIG. 54 is a side elevational view of an alternative embodiment of a rolled inner liner layer having a partially molded distal tip section. [Figure 55] FIG. 55 is a perspective view of the distal tip section of FIG. [Figure 56] 56 is a top plan view of the distal tip section of FIG. 54. [Figure 57] FIG. 57 is an enlarged view of a portion of FIG. [Figure 58]FIG. 58 is a side elevational view of the distal tip section of FIG. 54 receiving an intermediate layer to further shape the distal tip section. [Figure 59] FIG. 59 is a side elevational view of the distal tip section of FIG. 58 further assembled. [Figure 60] FIG. 60 is a perspective view of the distal tip section of FIG. 59 with an intermediate layer formed, such as by flow melting. [Figure 61] 61 is a side elevational view of the distal tip section of FIG. 60. FIG. [Figure 62] 62 is a top plan view of the distal tip section of FIG. 60. FIG. [Figure 63] FIG. 63 is a schematic diagram of an assembly process for the distal tip section of an expandable delivery sheath according to another embodiment of the present invention, including rolling and scoring an inner liner layer. [Figure 64] FIG. 64 is a schematic diagram of the assembly process including placing an intermediate tie layer over a molded inner liner and incorporating radiopaque markers in the distal tip section. [Figure 65] FIG. 65 is a schematic diagram of the assembly process, including further shaping of the intermediate layer of the distal tip section. [Figure 66] FIG. 66 is a side elevational view of a distal tip section of an expandable delivery sheath of another embodiment. [Figure 67] FIG. 67 is a side elevational view of an inner layer having an intermediate layer at least partially molded to the distal tip section. [Figure 68] FIG. 68 is a cross-sectional view of a tube for forming an intermediate layer in another embodiment. [Figure 69] FIGURE 69 is a cross-sectional view of a tube for forming an intermediate layer having three sublayers of an alternative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present disclosure may be more readily understood by reference to the following detailed description, examples, figures, and claims, as well as their preceding and following descriptions. However, before the present articles, systems, and / or methods are disclosed and described, it should be understood that the present disclosure is not limited to specific or exemplary aspects of the disclosed articles, systems, and / or methods, unless otherwise specified, and as such may, of course, vary. It should also be understood that the terminology used herein is for the purpose of describing aspects only, and is not intended to be limiting.

[0023] The following description of the present disclosure is provided as an enabling teaching of the present disclosure in its best currently known mode. To this end, those skilled in the relevant art will recognize and understand that many modifications can be made to the various aspects of the present disclosure described herein while still obtaining the beneficial results of the present disclosure. It will also be apparent that some of the desired benefits of the present disclosure can be obtained by selecting some of the features of the present disclosure without utilizing other features. Thus, those skilled in the relevant art will recognize that many modifications and adaptations to the present disclosure are possible and may even be desirable in certain circumstances, and are part of the present disclosure. Thus, the following description is again provided as an illustration, not a limitation, of the principles of the present disclosure. definition

[0024] As used in this application and the claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Thus, for example, reference to a "polymer" includes aspects having two or more such polymers, unless the context clearly dictates otherwise.

[0025] It should also be understood that the terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting. As used in this specification and claims, the term "comprising" can include embodiments of "consisting of" and "consisting essentially of." Additionally, the term "includes" means "comprises."

[0026] The terms "for example" and "such as," as well as their grammatical equivalents, are understood to be followed by the phrase "including but not limited to," unless expressly stated otherwise.

[0027] References in this specification and the concluding claims to the parts by weight of a particular element or component in a composition or article indicate the weight relationship between the element or component and any other element or component in the composition or article for which the parts by weight are expressed. Thus, in a composition or selected portion of a composition that includes 2 parts by weight of component X and 5 parts by weight of component Y, X and Y are present in a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are included in the composition.

[0028] Weight percentages of components are based on the total weight of the formulation or composition in which the component is included, unless specifically stated to the contrary.

[0029] Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It should be further understood that the endpoints of each of the ranges are significant both relative to the other endpoint, and independently of the other endpoint.

[0030] Throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Thus, the description of a range should be considered to have specifically disclosed all possible subranges and individual numerical values ​​within that range. For example, the description of a range such as 1-6 should be considered to have specifically disclosed subranges such as 1-3, 1-4, 1-5, 2-4, 2-6, 3-6, and individual numerical values ​​within that range, such as 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any whole and partial increments therebetween. This applies regardless of the breadth of the range.

[0031] As used herein, the term "substantially" when used in reference to a composition refers to at least about 80% by weight, at least about 85% by weight, at least about 90% by weight, at least about 91% by weight, at least about 92% by weight, at least about 93% by weight, at least about 94% by weight, at least about 95% by weight, at least about 96% by weight, at least about 97% by weight, at least about 98% by weight, at least about 99% by weight, or about 100% by weight of a specified feature or component, based on the total weight of the composition.

[0032] As used herein, the term "substantially" in the context of, for example, "substantially free" refers to a composition having less than about 1 wt. %, e.g., less than about 0.5 wt. %, less than about 0.1 wt. %, less than about 0.05 wt. %, or less than about 0.01 wt. % of a described material based on the total weight of the composition.

[0033] As used herein, the term "substantially identical reference composition" or "substantially identical reference article" refers to a reference composition or article that contains substantially identical components in the absence of the components of the invention. In another exemplary embodiment, the term "substantially," for example in the context of "substantially identical reference composition," refers to a reference composition that contains substantially identical components, where the components of the invention are replaced with components common in the art.

[0034] Furthermore, the terms "coupled" and "associated" generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or connected and do not exclude the presence of intermediate elements between the coupled or associated items.

[0035] As used herein, the term "atraumatic" is commonly known in the art and refers to an instrument or procedure that minimizes tissue damage.

[0036] As used herein, the terms or phrases "effective", "effective amount", or "conditions effective for" refer to an amount or condition that allows the function or property for which the effective amount or condition is expressed to be performed. As noted below, the exact amount or specific conditions required will vary from embodiment to embodiment, depending on recognized variables such as the materials employed and the process conditions observed. Thus, it is not always possible to specify an exact "effective amount" or "conditions effective for". However, an appropriate effective amount can be readily determined by one of ordinary skill in the art using only routine experimentation.

[0037] Although the operations of exemplary embodiments of the disclosed methods may be described in a particular sequential order for convenient presentation, it should be understood that the disclosed embodiments may encompass orders of operations other than the particular sequential order disclosed. For example, operations described as sequential may, in some cases, be rearranged or performed simultaneously. Moreover, descriptions and disclosures provided in connection with one particular embodiment are not limited to that embodiment and may be applicable to any disclosed embodiment.

[0038] Moreover, for simplicity, the attached figures may not show the various ways in which the disclosed systems, methods, and apparatus can be used in combination with other systems, methods, and apparatus, which would be readily discernible by one of ordinary skill in the art based on this disclosure. In addition, this description sometimes uses terms such as "produce" and "provide" to describe the disclosed methodologies. These terms are high-level abstractions of actual operations that may be performed. The actual operations that correspond to these terms may vary depending on the particular implementation, and would be readily discernible by one of ordinary skill in the art based on this disclosure. sheath

[0039] Disclosed herein is one embodiment of a sheath for delivering a medical device, the sheath having a proximal end and a distal end, the sheath having a first resting diameter d r and the second expansion diameter d e and a second surface of the inner liner defining a lumen having a first surface and an opposing second surface, the lumen being configured to receive and pass a medical device, the inner liner comprising a sheet including a first portion having a first surface and an opposing second surface, a first end of the first portion being divided into a first segment having the first surface and an opposing second surface and a third segment having the first surface and an opposing second surface, the second end of the first portion extending into the second segment having the first surface and an opposing second surface, the sheet being spirally configured such that at least a portion of the first surface of the second segment overlaps at least a portion of the second surface of the first segment. the third segment overlapping at least a portion of the second surface of the second segment, the third segment overlapping at least a portion of the second surface of the first segment, the first surface of the first portion extending over the first surface of the first segment, the second segment, and the third segment, and the second surface of the first portion extending over the second surface of the second segment and the third segment, the segments configured to slidably move along one another upon passage of the medical device through the lumen, the sheet comprising an inner liner and an outer layer.

[0040] In certain embodiments, the static diameter d r may be substantially uniform along the longitudinal axis of the lumen. r varies along the longitudinal axis of the lumen and has a rest diameter d at the distal end r The rest diameter at the proximal end, d, is greater than r In one disclosed embodiment, the expanded diameter d e is configured to accommodate passage of a medical device through the lumen. In another embodiment, the sheath has a predetermined resting diameter d after passage of the medical device through the lumen. r It can shrink up to

[0041] In one disclosed embodiment, the sheet of the sheath comprises high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof. In yet a further embodiment, the sheet can have a multi-layer structure. In a still further embodiment, the inner surface of the sheet is at least partially ribbed.

[0042] In one exemplary embodiment, the sheet is lubricious and has a coefficient of friction of less than about 0.5.

[0043] In yet a further aspect, a quantity of a first lubricant is disposed between at least a portion of the inner liner and at least a portion of the outer layer. In yet other disclosed aspects, a quantity of a second lubricant can be disposed between at least a portion of the overlapping portion of the sheet and at least a portion of the sliding portion of the sheet.

[0044] In yet other disclosed aspects, the outer surface of the layer of elastomeric polymer may define at least a portion of the outer surface of the outer layer. In some of the disclosed aspects, at least a portion of the inner surface of the layer of elastomeric polymer is at least partially bonded to at least a portion of the outer surface of the sheet of inner liner. In still further aspects, at least a portion of the inner surface of the layer of elastomeric polymer may define at least a portion of the inner surface of the outer layer, while in other aspects, at least a portion of the braid or coil may define at least a portion of the inner surface of the outer layer.

[0045] In one disclosed embodiment, the sheath may further comprise a first strip of elastomeric polymer disposed along at least a portion of the longitudinal axis of the lumen between at least a portion of the outer surface of the sheet not comprising the overlying portion of the sheet and the inner surface of the outer layer. In another embodiment, the sheath may further comprise a second strip of elastomeric polymer disposed between at least a portion of the outer surface of the sheet at a proximal end of the sheath and the inner surface of the outer layer, while in other embodiments, the sheath may further comprise a third strip of elastomeric polymer disposed between at least a portion of the outer surface of the sheet at a distal end of the sheath and the inner surface of the outer layer.

[0046] In still further aspects, the braid or coil is an expandable braid or coil. In still further aspects, the braid or coil can include at least one filament comprising stainless steel, nitinol, a polymeric material, or a composite material. In certain aspects, the at least one filament can be a round filament or a flat filament. In aspects where the at least one filament comprises a polymeric material, the polymeric material can be polyester or nylon. In aspects where the at least one filament is round, the round filament can have a diameter of less than about 0.015 inches. Meanwhile, in aspects where the at least one filament is flat, the flat filament can have a height of less than about 0.006 inches and a width of greater than about 0.003 inches to about 0.015 inches. In still further aspects, the braid can have a number of crosses per inch (PIC) of less than 50. In still further aspects, the PIC of the braid can vary along the longitudinal axis of the lumen.

[0047] In yet a further embodiment, where at least one filament is Nitinol, the Nitinol is d e At least one filament comprises stainless steel or nitinol, and in other embodiments, the filaments can be configured to be atraumatic at least at the distal end of the sheath.

[0048] In yet another embodiment, the elastomeric polymer present in the outer layer comprises a styrenic elastomer, a polyurethane, a latex, a copolymer thereof, a blend thereof, or a coextrusion thereof. In one embodiment, the elastomeric polymer exhibits a Shore A durometer of less than 90. In certain embodiments, the braid or coil may be at least partially embedded within at least a portion of the layer of elastomeric polymer. In yet another embodiment, a hydrophilic coating layer may be disposed on the outer surface of the outer layer.

[0049] Also disclosed herein are aspects that include methods of making a sheath having a proximal end and a distal end. In certain aspects, a method of making such a sheath includes the steps of forming a variable diameter inner liner by winding a sheet having a first edge and a second edge and defined by an inner surface and an outer surface into a spiral 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, thereby forming an overlapping portion, wherein 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, and the inner surface of the sheet defines a lumen of the sheath having a longitudinal axis; and an outer surface, the outer layer extending around at least a portion of the variable diameter inner liner such that the inner surface of the outer layer is positioned adjacent to the outer surface of the inner liner, the outer layer comprising a braid or coil and a layer of an elastomeric polymer having a predetermined thickness and having an inner surface and an outer surface, the variable diameter inner liner being configured to have a predetermined rest diameter d by sliding a first edge of the sheet along at least a portion of the inner surface and sliding a second edge of the sheet along at least a portion of the outer surface during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r From expansion diameter d e and configured to expand to

[0050] In some exemplary embodiments, the step of forming the variable inner liner includes winding the sheet onto a mandrel having a predetermined diameter to form a spiral configuration, the predetermined diameter of the mandrel being equal to the predetermined diameter d of the inner liner. r In yet a further embodiment, the static diameter d r is substantially uniform along the longitudinal axis of the lumen, while in other embodiments, the static diameter d r varies along the longitudinal axis of the lumen and has a rest diameter d at the distal end r The rest diameter at the proximal end, d, is greater than r In yet a further aspect, the expanded diameter d e is configured to accommodate passage of a medical device through the lumen, while in other embodiments, the sheath formed by the methods disclosed herein has a predetermined resting diameter d after passage of a medical device through the lumen. r It can shrink up to

[0051] In still further aspects, forming the outer layer includes mounting the braid or coil onto the inner liner. In still further aspects, forming the outer layer further includes mounting an elastomeric polymer onto the braid or coil. In some exemplary aspects, the methods disclosed herein may further include at least partially embedding the braid or coil within at least a portion of the layer of elastomeric polymer. In still other exemplary aspects, forming the outer layer may include mounting a layer of elastomeric polymer onto the braid or coil and then mounting the layer of elastomeric polymer and the braid or coil onto the inner liner positioned on the mandrel. In such exemplary aspects, the method may further include at least partially embedding the braid or coil within at least a portion of the layer of elastomeric polymer prior to mounting onto the inner liner. While in other aspects, the method may further include at least partially embedding the braid or coil within at least a portion of the layer of elastomeric polymer after mounting onto the inner liner. In still further aspects, after the outer layer is mounted onto the inner liner and bonding is completed, the sheath is removed from the mandrel.

[0052] In other aspects, in the methods disclosed herein, an outer surface of the layer of elastomeric polymer can define at least a portion of the outer surface of the outer layer. Also, in other aspects, in the methods disclosed herein, at least a portion of the inner surface of the layer of elastomeric polymer can define at least a portion of the inner surface of the outer layer. Still further disclosed herein are aspects where at least a portion of the braid or coil can define at least a portion of the inner surface of the outer layer.

[0053] In certain embodiments, the methods disclosed herein further include bonding at least a portion of the inner surface of the layer of elastomeric polymer to at least a portion of the outer surface of the sheet of inner liner. In one embodiment, the bonding is performed by heating at a temperature of about 350° F. to about 550° F. for a period of time effective to form a bond between at least a portion of the outer layer and at least a portion of the inner liner.

[0054] One embodiment includes a method as described herein, in which a first strip of elastomeric polymer is applied along at least a portion of the longitudinal axis of the lumen to at least a portion of the outer surface of the sheet not including the overlay portion prior to or during the step of joining at least a portion of the inner surface of the layer of elastomeric polymer to at least a portion of the outer surface of the sheet of the inner liner. In yet another embodiment, a second strip of elastomeric polymer may be applied to at least a portion of the outer surface of the sheet at a proximal end of the sheath prior to or during the step of joining at least a portion of the inner surface of the layer of elastomeric polymer to at least a portion of the outer surface of the sheet of the inner liner. In yet a further embodiment, a third strip of elastomeric polymer may be applied to at least a portion of the outer surface of the sheet at a distal end of the sheath prior to or during the step of joining at least a portion of the inner surface of the layer of elastomeric polymer to at least a portion of the outer surface of the sheet of the inner liner.

[0055] In still further aspects, a quantity of the first lubricant may be applied to at least a portion of the inner liner prior to the step of forming the outer layer such that the quantity of the first lubricant is disposed within the sheath between at least a portion of the inner liner and at least a portion of the outer liner, while in other aspects, a quantity of the second lubricant is applied to at least a portion of the overlapping portion and the sliding portion of the sheet prior to the step of forming the outer layer, as described herein.

[0056] In other aspects, in the methods described herein, the sheet may comprise high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof. In yet other aspects, the sheet may have a multi-layer structure. In yet further aspects, the inner surface of the sheet may be at least partially ribbed. In yet other aspects, the sheet may be lubricious and 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, or less than about 0.1.

[0057] In still further aspects, the methods disclosed herein include a braid or coil, where the braid or coil is an expandable braid or coil. In still further aspects, the braid or coil of the disclosed methods can include at least one filament comprising stainless steel, nitinol, a polymeric material, or a composite material. In certain aspects, at least one of the filaments can be a round filament or a flat filament. In certain aspects, the polymeric material present in the braid can be polyester or nylon. In aspects where at least one filament is a round filament, such filament can have a diameter of less than about 0.015 inches. In yet other embodiments where at least one filament is a flat filament, such filaments can have a height of less than about 0.006 inches and a width of greater than about 0.003 inches to about 0.015 inches, with 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 0.010 inches, about 0.011 inches, about 0.012 inches, about 0.013 inches, and about 0.014 inches. In embodiments of the methods disclosed herein, the braid can have a number of crosses per inch (PIC) of less than 50, less than 45, less than 40, or even less than 35. In still further exemplary embodiments, the PIC can vary along the longitudinal axis of the lumen.

[0058] In embodiments in which at least one filament comprises Nitinol, the Nitinol is e In embodiments in which at least one filament comprises stainless steel or nitinol, the filament is configured to be atraumatic at least at the distal end of the sheath.

[0059] In yet further aspects, the methods disclosed herein include an elastomeric polymer comprising a styrenic elastomer, a polyurethane, a latex, a copolymer thereof, a mixture thereof, or a coextrusion thereof. In yet further aspects, the elastomeric polymer may exhibit a Shore A durometer of less than 90. In still further aspects, the methods may further include disposing a hydrophilic coating layer on an outer surface of the layer of elastomeric polymer.

[0060] In some methods, a soft tip portion may be coupled to a distal end of the expandable sheath to facilitate passing the expandable sheath through the patient's vasculature.

[0061] The disclosed embodiments of the expandable sheath can minimize trauma to the vessel by allowing a temporary expansion of a portion of the introducer sheath to accommodate the delivery system, followed by return to the original diameter once the device has passed. In some embodiments, the sheath can comprise a sheath having a smaller profile (e.g., smaller diameter in the resting configuration) than that of prior art introducer sheaths. Additionally, the present embodiments can reduce the length of time a procedure takes, and further reduce the risk of longitudinal or radial vessel tearing or plaque detachment, since only one sheath is required, rather than several different sizes of sheaths. The present expandable sheath embodiments can avoid the need for multiple insertions for vessel expansion. Such expandable sheaths can be useful for many types of minimally invasive surgical procedures, such as any surgical procedure that requires the introduction of a device into a subject's vessel. For example, the sheath may be used to introduce other types of delivery devices for placing various types of intraluminal devices (e.g., stents, prosthetic heart valves, stented grafts, etc.) within many types of vascular and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary system ducts, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.).

[0062] FIG. 1 shows a sheath 8 according to the present disclosure used with a representative delivery device 10 for delivering a prosthesis 12, such as a tissue heart valve, to a patient. The device 10 can include a steerable guide catheter 14 (also referred to as a flex catheter), a balloon catheter 16 extending through the guide catheter 14, and a nasal catheter 18 extending through the balloon catheter 16. The guide catheter 14, balloon catheter 16, and nasal catheter 18 in the illustrated embodiment are adapted to slide longitudinally relative to one another to facilitate delivery and positioning of the valve 12 at an implantation site within the patient's body, as described in detail below. Generally, the sheath 8 is inserted through the patient's skin into a blood vessel, such as a transfemoral vessel, such that a distal end of the sheath 8 is inserted into the blood vessel. The sheath 8 can include a hemostasis valve at the opposite proximal end of the sheath. The delivery device 10 can be inserted into the sheath 8, and the prosthesis 12 can then be delivered and implanted into the patient.

[0063] 2A and 2B show cross-sectional views of two exemplary sheath embodiments disclosed herein for use with a delivery device such as that shown in FIG. 1. FIG. 2C shows a perspective view of one embodiment of an inner liner 202 for use with the disclosed sheath. As shown in FIGS. 2A-C, in some embodiments, the disclosed sheath comprises an inner liner 202 wound in a spiral 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, with a first edge 202a of the sheet being slidable along at least a portion of the inner surface of the sheet and a second edge 202b being slidable along at least a portion of the outer surface of the sheet. As shown in FIGS. 2A and 2B, the sheath may further include an outer layer including a braid (or coil) 204 and a layer 206 of an elastomeric polymer. In one embodiment, as shown in FIG. 2A, the outer layer may include a braid (or coil) 204 that is not embedded in the layer 206 of an elastomeric polymer. While in other embodiments, as shown in FIG. 2B, the outer layer can include a braid (or coil) 204 embedded in a layer 206 of elastomeric polymer.

[0064] The inner liner 202 defines a lumen 201 through which a delivery device can be advanced into the patient's vasculature to deliver, remove, repair, and / or replace a prosthesis. The disclosed sheaths can also be useful for other types of minimally invasive procedures, such as any surgical procedure that requires the introduction of a device into a subject's vasculature. For example, the disclosed sheaths can also be used to introduce other types of delivery devices for placing various types of endoluminal devices (e.g., stents, stented grafts, etc.) into many types of vascular and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary system ducts, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.).

[0065] In still further aspects, the sheet used to make the inner liner 202 can include high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof. In still further aspects, the sheet can include one or more layers. In some aspects, when one or more layers are present, each layer can include the same or different polymers. In still further aspects, the sheet can have a predetermined thickness, which can be defined by one of skill in the art depending on the specific application. In certain aspects, the predetermined thickness of the inner liner can be about 0.002 inches to about 0.025 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 can be varied depending on the desired amount of radial expansion as well as the strength required.

[0066] In still further embodiments, the inner surface of the sheet may be at least partially ribbed. In still further embodiments, the sheet may also be lubricious. 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 lubricious inner liner include materials that may reduce the coefficient of friction of the inner liner 202, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for the lubricious liner also include other materials that desirably have 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.

[0067] In still further embodiments, the outer layer, including the braid or coil and the layer of elastomeric polymer, can have any predetermined thickness. It is understood that the predetermined thickness of the outer layer can depend on the specific application of the sheath. For example, but not limited to, the thickness of the inner liner 202 and the outer layer, including the braid (or coil) 204 and the layer of elastomeric material 206, can also vary depending on the specific application of the disclosed sheath. In some embodiments, the thickness of the inner liner 202 ranges from 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, about 0.009 inches, and in one particular embodiment, the thickness can be about 0.002 inches. The outer layer, including the braid (or coil) 204 and the layer of elastomeric material 206, can have a thickness of about 0.002 inches to about 0.015 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, and about 0.01 inches.

[0068] It is understood that the inner liner can have any shape or configuration depending on the desired application and 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 still further aspects, the outer layer, including the braid or coil and the layer of elastomeric polymer, can at least partially conform to the shape or configuration of the inner liner. In certain aspects, the sheaths disclosed herein have a resting diameter d r and outer diameter d o As disclosed herein, the static diameter d r The diameter may be defined by the inner liner, while the outer diameter may be defined by the inner liner and an outer layer, the outer layer comprising a braid or coil and a layer of elastomeric polymer.

[0069] The static diameter d of the inner liner 202 rcan vary depending on the application and size of the delivery device and prosthesis. Figures 3A-3C show various configurations and shapes of the inner liner. In some embodiments, the rest diameter d, as shown in Figure 3B, r It will be appreciated that the rest diameter d is substantially uniform along the longitudinal axis of the lumen, without variation from the proximal end 308 to the distal end 306. In yet another embodiment, the rest diameter d r is the longitudinal axis of the lumen (e.g., d in FIG. 3A). r1 and d r2 , or d as shown in FIG. 3C r1 , d r2 , d r3 , and d r4 ) at the proximal end 304 or 312. r1 d at the distal end 302 or 310 r The static diameter d r2 Or as shown in FIG. 3C r4 In yet a further embodiment, the outer layer conforms to the shape of the inner liner and has an outer diameter d o (not shown) includes the overall diameter of the inner liner and outer layer. In such an embodiment, the outer diameter d o is determined by the specific application of the sheath. r Similarly, the outer diameter d of the non-expandable sheath disclosed herein o can be substantially uniform (constant) along the longitudinal axis of the lumen without varying from the proximal end to the distal end (not shown). In an alternative embodiment, the original unexpanded outer diameter d of the disclosed sheaths o is the static diameter d r Similarly, the static diameter d may decrease from the proximal end to the distal end. r Similarly, the original unexpanded outer diameter may decrease along a gradient from the proximal end to the distal end, or may have a largest original unexpanded outer diameter d o , and the smallest original unexpanded outer diameter d near the distal end o The sheath may be tapered incrementally along its length, having a thickness of 0.1 mm.

[0070] In some embodiments, the static diameter d rcan range from about 0.005 inches to about 0.400 inches, with exemplary values ​​of about 0.01 inches, about 0.02 inches, about 0.03 inches, about 0.04 inches, about 0.05 inches, about 0.06 inches, about 0.07 inches, about 0.08 inches, about 0.09 inches, about 0.1 inches, about 0.2 inches, and about 0.3 inches. As noted above, in certain embodiments, the sheath can be configured with various d r In such an embodiment, the inner liner may have a r can have any value between any two of the aforementioned values ​​and may depend on the particular application and the size and shape of the delivery device and prosthesis. Depending on the size requirements of the delivery device for various applications, different sheaths may have different expanded and unexpanded resting diameters d r and outer diameter d o Additionally, some embodiments may provide more or less expansion depending on the particular design parameters, materials, and / or configurations used.

[0071] As disclosed herein, the outer layer of the sheath has an inner surface and an outer surface. The outer layer of the disclosed sheath extends around at least a portion of the variable diameter inner liner such that the inner surface of the outer layer is positioned adjacent to the outer surface of the inner liner. As disclosed herein, the outer layer comprises a braid (or coil) 204 and a layer 206 of an elastomeric polymer having a predetermined thickness and having an inner surface and an outer surface (as shown in FIGS. 2A and 2B). In certain aspects, the braid or coil can be an expandable braid or coil. In still further aspects, the braid or coil can include at least one filament including stainless steel, nitinol, a polymeric material, or a composite material. In certain non-limiting aspects, the braid or coil includes filaments including nitinol and / or other shape memory alloys. In still other non-limiting aspects, the braid can have filaments including polyester or nylon. In still some other exemplary aspects, the braid can include filaments including Spectra fibers, polyethylene fibers, aramid fibers, or combinations thereof.

[0072] It is understood that the braid or coil may have any configuration known in the art. In certain aspects, the braid (or coil) 204 is generally a thin, hollow, substantially cylindrical tube comprising an arrangement, pattern, structure, or configuration of filaments or struts, although other geometries may be used. Suitable filaments may be round, 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 other embodiments, suitable filaments may be round and have a diameter ranging from about 0.0005 inches thick to about 0.015 inches thick, with 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 other embodiments, suitable filaments can be flat filaments having heights 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 other embodiments, flat filaments can have widths of greater 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 geometries and sizes are also suitable for certain embodiments.

[0073] In still further aspects, the braid can have a number of crosses per inch (PIC) less than 50, less than 40, less than 30, less than 20, or less than 10. In still other aspects, the braid can have a PIC number between 10 and 2, with exemplary values ​​of 9, 8, 7, 6, 5, 4, and 3. In still further aspects, the PIC can vary along the longitudinal axis of the lumen. In still other aspects, the braid pattern can vary along the longitudinal axis of the lumen. In aspects where the braid or coil comprises a filament that is Nitinol, the Nitinol has an expanded diameter d e In yet further embodiments, where the filaments comprise stainless steel or nitinol, the filaments are configured to be atraumatic at least at the distal end of the sheath. Figures 4A-4D illustrate partial elevational views of various configurations of the braid 28. It is understood that the configuration of the braid 28 may vary from section to section and along the length of the sheath. It is further understood that the configurations shown in Figures 4A-4D are not necessarily drawn to scale and represent exemplary and non-limiting embodiments only. It is further understood that the braid is configured to provide torqueability of the sheath during insertion of the prosthesis.

[0074] In still further embodiments, the outer layer includes a layer 206 of elastomeric polymer, as shown in Figures 2A and 2B. In certain embodiments, the elastomeric polymer may include styrenic elastomers, polyurethanes, latexes, copolymers thereof, mixtures thereof, or coextrusions thereof. In specific, non-limiting embodiments, the elastomeric polymer may include polyether block ester copolymers, polyesters, polyvinyl chloride, thermoset silicones, polyisoprene rubbers, polyolefins, other medical grade polymers, or combinations thereof. In still further embodiments, the elastomeric polymers described herein may have any useful additive. In certain embodiments, the elastomeric polymer may include at least one friction reducing additive. In some exemplary embodiments, the friction reducing additive may be, for example, BaSO4. 4, ProPell™, PTFE, any combination thereof, etc. It is understood that this list of friction reducing additives is not limiting and any friction reducing additive known in the art may be utilized.

[0075] It is understood that the hardness of each layer of the disclosed sheath may also vary depending on the particular application and desired properties of the sheath. In some embodiments, the layer of elastomeric polymer 206 has a Shore hardness of less than 90 durometer, less than 80 durometer, less than 70 durometer, less than 60 durometer, less than 50 durometer, less than 40 durometer, less than 30 durometer, or less than 20 durometer. In still further exemplary embodiments, the layer of elastomeric polymer 206 has a Shore hardness of about 25 durometer to about 75 durometer, with exemplary values ​​of about 30 durometer, about 35 durometer, about 40 durometer, about 45 durometer, about 50 durometer, about 55 durometer, about 60 durometer, about 65 durometer, and about 70 durometer.

[0076] Alternative embodiments of sheaths for introducing a prosthesis are also described. For example, Figures 5A-5B illustrate cross-sectional views of inner liners 500A and 500B of the disclosed sheaths in unexpanded and expanded configurations (Figures 5A and 5B, respectively). Upon introduction of a prosthesis into the inner liner, first edge 502 and second edge 504 slide along the inner liner, forming a resting diameter d r From expansion diameter d e , thereby shortening the inner liner overlay portion 506. e It will be appreciated that the sheath is configured to accommodate passage of a medical device through the lumen. In yet a further aspect, the sheath has a predetermined resting diameter d after passage of a medical device through the lumen. r Contracts until

[0077] In certain embodiments, an amount of a first lubricant is disposed between at least a portion of the inner liner and at least a portion of the outer layer. In other embodiments, an amount of a second lubricant is disposed 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 lubricant and the second lubricant can be the same or different. In certain non-limiting embodiments, the first and / or second lubricant can include Christo Lube supplied by ECL or MED10 / 6670 supplied by Nusil. In still further embodiments, it is understood that the amount of the first and / or second lubricant can be easily determined by one skilled in the art.

[0078] In still further aspects, the outer surface of the layer of elastomeric polymer defines at least a portion of the outer surface of the outer layer. In yet other aspects, at least a portion of the inner surface of the layer of elastomeric polymer is at least partially bonded to at least a portion of the outer surface of the sheet of inner liner. In one aspect, at least a portion of the inner surface of the layer of elastomeric polymer defines at least a portion of the inner surface of the outer layer, while in other aspects, at least a portion of the braid defines at least a portion of the inner surface of the outer layer. It is understood that the outer layer of the disclosed sheaths is configured to provide hemostasis and prevent bleeding of the patient during the procedure.

[0079] 6A-6D show other alternative embodiments of sheaths for introducing a prosthesis. FIG. 6A shows a sheath 600A comprising an inner liner 602 having a first edge 602a and a second edge 602b and an overlapping portion 602c, the inner and outer surfaces of the inner liner overlapping each other. The sheath 600A further comprises a quantity of a second lubricant 608 as disclosed herein disposed between the sliding portion of the inner sheath and the overlapping portion. The sheath further comprises a braid 604 and a layer 606 of an elastomeric polymer. In this exemplary embodiment, the braid 604 is not embedded in the layer 606 of an elastomeric polymer. FIG. 6B depicts an alternative embodiment of the sheath 600B in which a quantity of a first lubricant 610 is applied between the inner liner and the outer layer comprising the braid 604 and the layer 606 of an elastomeric polymer. An additional embodiment of the sheath 600C is shown in FIG. 6C. In this embodiment, the sheath 600C comprises an inner liner 602 having a first edge 602a and a second edge 602b, and an overlapping portion 602c, and the inner and outer surfaces of the inner liner overlap one another. The sheath further comprises a braid 604 and a layer 606 of an elastomeric polymer, which together form an outer layer of the sheath. The sheath 600C further comprises a quantity of a first lubricant 610, as 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 layer 606 of the elastomeric polymer. In the exemplary embodiment shown in FIG. 6D, the exemplary sheath 600D comprises a braid 604 embedded within the layer 606 of the elastomeric polymer.

[0080] In still further aspects, the sheaths of the present disclosure may include a hemostatic valve inside the lumen of the sheath at or near the proximal end of the sheath. Additionally, exemplary sheaths disclosed herein may include a soft tip at the distal end of the sheath. Such a soft tip may be provided with a lower hardness than other portions of the sheath. In some aspects, 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 other aspects, the soft tip can 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.

[0081] In certain embodiments, the outer layer and the inner liner may be bonded together or otherwise physically associated with one another. It is understood that the amount of adhesion between the inner liner 602 and the outer polymer layer comprising the braid 604 and the layer of elastomeric polymer 606 may vary across the surface of the layer. The bond between the layers may be created, for example, by thermal bonding. In certain embodiments, the bond may be facilitated by the presence of additional portions of elastomeric polymer. For example, in certain embodiments, the sheath may further comprise a first strip 611 of elastomeric polymer disposed along at least a portion of the longitudinal axis of the lumen between at least a portion of the outer surface of the sheet not comprising the overlapping portion 602c of the sheet and the inner surface of the outer layer, as described herein and shown in FIGS. 6H-6I. In such embodiments, the bond between the outer layer and the inner liner may be facilitated by the first strip of elastomeric polymer. In yet other embodiments, the sheath may further comprise a second strip 611 of elastomeric polymer disposed 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 outer layer (FIGS. 6E-6F). In still further embodiments, the sheath may further comprise a third strip 611 of elastomeric polymer disposed 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 outer layer (FIGS. 6E and 6G). Again, in such embodiments, bonding between the outer layer and the inner liner may be facilitated by the second and / or third strips of elastomeric polymer.

[0082] Applications include expanded diameters d of about 3 Fr to about 26 Fr, with 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. e The inner liner 602 has a rest diameter d rA sheath of the present disclosure having an expanded diameter may be utilized. The expanded diameter may vary 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, with 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, with 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. Embodiments of the disclosed sheaths can be expanded to expanded outer diameters from about 10% greater than the original unexpanded outer diameter to about 100% greater than the original unexpanded outer diameter, including exemplary values ​​of about 15% greater, about 20% greater, about 25% greater, about 30% greater, about 35% greater, about 40% greater, about 45% greater, about 50% greater, about 55% greater, about 60% greater, about 65% greater, about 70% greater, about 75% greater, about 80% greater, about 85% greater, about 90% greater, and about 95% greater than the original unexpanded outer diameter.

[0083] As described above, it is understood that the disclosed sheaths can be expanded from their rest position. The expansion of the disclosed sheaths can range from about 10% or less to about 430% or more of their rest diameter d r In certain embodiments, the expansion of the sheath can result in an expansion to a static diameter d r In yet other embodiments, the expansion of the disclosed sheaths can result in expansion to about 10% or less, about 9% or less, about 8% or less, about 7% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, or about 1% or less of the static diameter d r In some embodiments, the expansion may result in an expansion of up to about 10% or more, about 20% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, about 70% or more, about 80% or more, about 90% or more, about 100% or more, about 125% or more, about 150% or more, about 175% or more, about 200% or more, about 225% or more, or about 250% or more of the total expansion.

[0084] As with the previously disclosed embodiments, the embodiment illustrated in FIGS. 6A-6D can be configured with a wide variety of static diameters d r and outer diameter d oIn some embodiments, the sheath may have an outer diameter d o 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 sheath diameter d may gradually decrease from about 26 Fr at the proximal end to about 18 Fr at the distal end. o may transition gradually over substantially the entire length of the sheath. In other aspects, the transition or reduction in 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 approximately the entire length of the sheath, including any value between any two of the aforementioned values. In still further aspects, d o is minimal and constant along the section of the sheath that passes through the vasculature. In such embodiments, the tapered section is about 4 inches or less proximal to the sheath.

[0085] In some embodiments, the outer layer, including the braid and the layer of elastomeric polymer, may comprise the same material or combination of materials along its entire length. In alternative embodiments, the material composition of the outer layer may vary along the length of the sheath. For example, the outer layer may be provided with one or more segments, with the composition varying from segment to segment. For example, in one segment, the braid may comprise Nitinol having a different PIC number than another segment. In yet another exemplary embodiment, the layer of elastomeric material in one segment may be different from the layer of elastomeric material in another segment. In still further exemplary embodiments, one segment of the sheath may comprise a braid or coil embedded within a layer of elastomeric polymer material, while another segment may comprise a braid or coil that is not embedded within a layer of elastomeric polymer material. It is understood that the exemplary sheaths disclosed herein are not limiting. In certain exemplary embodiments, the sheath may comprise n segments, with each segment being the same or different. In still further exemplary aspects, the durometer rating of the outer layer composition may also vary along the length of the sheath, such that a segment near the proximal end includes a stiffer material or combination of materials, while a segment near the distal end includes a softer material or combination of materials. This may enable a sheath that has a relatively stiff proximal end at the point of introduction of the delivery device, yet still has a relatively soft distal tip at the point of entry into the patient's vasculature.

[0086] 10 and 11 illustrate an expandable sheath 100 according to the present disclosure that may be used with a delivery device for delivering a prosthesis, such as a tissue heart valve, into a patient. In general, the delivery device may include a steerable guide catheter (also referred to as a flex catheter) (e.g., as depicted in FIG. 1 ) and a balloon catheter extending through the guide catheter. The guide catheter, balloon catheter, and nasal catheter may be adapted to slide longitudinally relative to one another to facilitate delivery and positioning of the valve at an implantation site within the patient's body. However, it should be noted that the sheath 100 may be used with any type of elongated delivery device used to implant balloon-expandable prosthetic valves, self-expanding prosthetic valves, and other prostheses. In general, the sheath 100 may be inserted into a blood vessel (e.g., the femoral artery or iliac artery) by passing through the patient's skin such that a soft tip portion 102 at a distal end 104 of the sheath 100 is inserted into the blood vessel. The sheath 100 may also include a proximal wide-mouthed end portion 114 to facilitate mating with the introducer housing 101 and the catheter described above (e.g., the proximal wide-mouthed end portion 114 may provide a compression fit over the housing tip and / or the proximal wide-mouthed end 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 contain one or more valves that, when inserted through the housing, form a seal around the outer surface of a delivery device, as is known in the art. The delivery device may be inserted into and through the sheath 100 to allow the prosthesis to be advanced through the patient's vasculature and implanted within the patient.

[0087] In an exemplary embodiment, the sheath 100 comprises an inner liner 108 and an outer layer 110 disposed about the inner liner 108. The outer layer 110 includes a braid (or coil) 111 and a layer of elastomeric polymer 113. FIG. 11 illustrates one non-limiting embodiment in which the braid (or coil) 111 is embedded in the layer of elastomeric polymer 113. The inner liner 108 has a resting diameter d 112 through which a delivery device can be advanced into a patient's vasculature to deliver, remove, repair, and / or replace a prosthesis, moving in a direction along a longitudinal axis X. r When the prosthesis passes through the sheath 100, the sheath defines a resting diameter d r From expansion diameter d e After the prosthesis has passed through a particular location in the sheath 100, each successively expanded portion or segment of the sheath 100 expands to a resting diameter d r In this manner, the sheath 100 may be considered self-expanding in that it does not require the use of balloons, dilators, and / or obturators to expand.

[0088] As shown herein, the inner layer 108 and the outer layer 110 can comprise any of the materials disclosed above.

[0089] In addition, some embodiments of the sheath 100 may include an exterior hydrophilic coating on the outer surface of the outer layer 110. Such a hydrophilic coating may facilitate insertion of the sheath 100 into a patient's blood vessel. Examples of suitable hydrophilic coatings include Harmony™ Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, Minnesota. 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.

[0090] As best seen in FIG. 11, the soft tip portion 102, in some embodiments, can include low density polyethylene (LDPE) and can be configured to minimize trauma or damage to the patient's blood vessels as the sheath is navigated through the vasculature. For example, in some embodiments, the soft tip portion 102 can be slightly tapered to facilitate passage through the blood vessels. The soft tip portion 102 can be secured to the distal end 104 of the sheath 100, such as by thermally bonding the soft tip portion 102 to the inner and outer layers of the sheath 100. Such a soft tip portion 102 can be provided with a lower hardness than other portions of the sheath 100. In some embodiments, the soft tip 102 can have a Shore hardness of about 25A to about 40A, including exemplary values ​​of about 28A, about 30A, about 32A, about 35A, and about 38A. It is further understood that the Shore hardness can have any value between any two of the aforementioned values. In yet other aspects, the soft tip 102 can have a Shore hardness of about 25D to about 40D, with exemplary values ​​of about 28D, about 30D, about 32D, about 35D, and about 38D. The tip portion 102 is configured to be radially expandable to allow a prosthesis to pass through the distal opening of the sheath 100.

[0091] 11, the sheath 100 may optionally include at least one radiopaque filler or marker, such as a discontinuous or C-shaped band 112 positioned near the distal end 104 of the sheath 100. The marker 112 may be associated with the inner liner and / or the outer layers 108, 110 of the sheath 100. Such radiopaque tip markers may include materials suitable for radiopaque fillers, such as platinum, iridium, platinum / iridium alloys, stainless steel, other biocompatible metals, or combinations thereof. 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 layer of elastomeric polymer used to form the outer layer and may comprise from about 5% to about 45% by weight of the outer layer, with exemplary values ​​of about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, and about 40% by weight of the outer polymeric tubular layer. More or less radiopaque material may be used in some embodiments, depending on the particular application.

[0092] 12A-12B show cross-sectional views of sheath 100 taken near distal end 104 of sheath 100. FIG.

[0093] FIG. 12A shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the sliding portion and the overlay portion of the sheet, and a braid that is not embedded in the elastomeric polymer layer. More specifically, FIG. 12A shows a sheath 1200A with an inner liner 1202 having a first edge 1202a and a second edge 1202b, and an overlay portion 1202c, where the inner and outer surfaces of the inner liner overlap each other. The sheath 1200A further includes a quantity of a second lubricant 1208 as disclosed herein disposed between the sliding portion and the overlay portion of the inner sheath. The sheath further includes a braid (or coil) 1204 and a layer 1206 of elastomeric polymer. In this exemplary embodiment, the braid (or coil) 1204 is not embedded in the layer 1206 of elastomeric polymer.

[0094] 12B shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the sliding portion of the sheet and the overlay portion and a lubricant disposed between the inner liner and the outer layer, where the braid is not embedded in the elastomeric polymer layer. More specifically, FIG. 12B depicts an alternative embodiment of a sheath 1200B in which a quantity of a first lubricant 1210 is applied between the inner liner and the outer layer comprising a braid (or coil) 1204 and a layer of elastomeric polymer 1206.

[0095] An additional embodiment of the sheath 1200C is shown in FIG. 12C. FIG. 12C shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the inner liner and the outer layer, where the braid is not embedded in the elastomeric polymer layer, with and without the lubricant. More specifically, in this embodiment, the sheath 1200C comprises an inner liner 1202 having a first edge 1202a and a second edge 1202b, and an overlapping portion 1202c, where the inner and outer surfaces of the inner liner overlap each other. The sheath further comprises a braid (or coil) 1204 and a layer of elastomeric polymer 1206 that together form the outer layer of the sheath. The sheath 1200C further comprises a quantity of a first lubricant 1210 as disclosed herein disposed between the outer layer of the inner sheath and the inner liner. In this exemplary embodiment, the braid (or coil) 1204 is not embedded in the layer of elastomeric polymer 1206. 12D shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the sliding portion of the sheet and the overlay portion and a lubricant disposed between the inner liner and the outer layer, where the braid is at least partially embedded in the elastomeric polymer layer. More specifically, in this exemplary embodiment shown in FIG. 12D, the exemplary sheath 1200D includes a braid (or coil) 1204 embedded within a layer 1206 of elastomeric polymer.

[0096] 13A-D show cross-sectional views of the proximal section of the sheath taken along line 38-38 of FIG.

[0097] FIG. 13A shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the sliding portion and the overlay portion of the sheet, and a braid that is not embedded in the elastomeric polymer layer. More specifically, FIG. 13A shows a sheath 1300A with 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 includes a quantity of a second lubricant 1308 as disclosed herein disposed between the sliding portion and the overlay portion of the inner sheath. The sheath further includes a braid (or coil) 1304 and a layer 1306 of elastomeric polymer. In this exemplary embodiment, the braid (or coil) 1304 is not embedded in the layer 1306 of elastomeric polymer.

[0098] FIG. 13B shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the sliding portion of the sheet and the overlay portion, and a lubricant disposed between the inner liner and the outer layer, where the braid is not embedded in the elastomeric polymer layer. More specifically, FIG. 13B depicts an alternative embodiment of sheath 1300B in which a quantity of a first lubricant 1310 is applied between the inner liner and the outer layer comprising a braid (or coil) 1304 and a layer of elastomeric polymer 1306. An additional embodiment of sheath 1300C is shown in FIG. 13C. FIG. 13C shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the inner liner and the outer layer, where the braid is not embedded in the elastomeric polymer layer, with and without lubricant. More specifically, in this embodiment, the sheath 1300C comprises an inner liner 1302 having a first edge 1302a and a second edge 1302b, and an overlapping portion 1302c, where the inner and outer surfaces of the inner liner overlap one another. The sheath further comprises a braid (or coil) 1304 and a layer of elastomeric polymer 1306 that together form an outer layer of the sheath. The sheath 1300C further comprises a quantity of a first lubricant 1310 as disclosed herein disposed between the outer layer of the inner sheath and the inner liner. In this exemplary embodiment, the braid (or coil) 1304 is not embedded in the layer of elastomeric polymer 1306.

[0099] 13D shows a cross-sectional view of an exemplary sheath having a lubricant disposed between the sliding portion of the sheet and the overlay portion, and a lubricant disposed between the inner liner and the outer layer, where the braid is at least partially embedded in the elastomeric polymer layer. In this exemplary embodiment, the sheath 1300D includes a braid (or coil) 1304 embedded within a layer 1306 of elastomeric polymer.

[0100] In yet further aspects, as shown in FIG 14, the sheath 1400, whether having a braid or coil embedded within a layer of elastomeric polymer (as shown in FIG 14) or a braid or coil not embedded within a layer of elastomeric polymer, is configured to expand from a rest configuration to an expanded configuration as shown in FIG 15. In such aspects, the first and second edges (1502a and 1502b) of the inner liner slide such that the length of the overlapping portion shortens. In some exemplary aspects, this movement may be facilitated by the presence of a first and / or second lubricant, as disclosed above.

[0101] The sheaths disclosed herein can be configured to locally expand at specific locations corresponding to the location of a medical device along the length of the lumen, and then locally contract as the medical device passes that specific location. Thus, as a medical device is introduced through the sheath, it progresses longitudinally along the length of the sheath, and ridges may be visible that represent successive local expansions and contractions as the device progresses down the length of the sheath. In some aspects, each segment of the sheath expands or contracts relative to the original resting diameter d of the lumen. r . may locally shrink after removal of any radially outward (insertion) force so as to regain

[0102] In some embodiments, each segment of the sheath has an original resting diameter d r After any outward radial force is removed, the localized contraction can occur at least partially back to normal.

[0103] Additional sheath 8 configurations are also disclosed that may be utilized with the delivery device 10 as shown in FIG. 1 for delivery of the prosthesis 12.

[0104] For example, but not by way of limitation, FIGS. 21A-21B depict one exemplary embodiment of a sheath disclosed herein. In such an embodiment, the sheath includes a proximal end and a distal end. The sheath 2100 can include a variable diameter inner liner 2102 including a sheet having a first edge 2104 and a second edge 2106, and is defined by an inner surface 2102a and an outer surface 2102b. When the sheet is wound in a spiral configuration, at least a portion of the inner surface 2102a of the sheet covers at least a portion of the outer surface 2102b of the sheet. As can be seen in FIGS. 21A-B, the first edge 2104 of the sheet is slidable along at least a portion of the inner surface 2102a of the sheet, and the second edge 2106 is slidable along at least a portion of the outer surface 2102b of the sheet. The sheath further includes an outer layer 2108 having an inner surface 2108a and an outer surface 2108b.

[0105] The inner surface 2102a of the sheet further defines a lumen of the sheath through which a delivery device can be advanced into the patient's vasculature to deliver, remove, repair, and / or replace the prosthesis. The disclosed sheaths can also be useful for other types of minimally invasive procedures, such as any surgical procedure that requires the introduction of a device into a subject's vasculature. For example, the disclosed sheaths can also be used to introduce other types of delivery devices for placing various types of endoluminal 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.).

[0106] It is further understood that the sheath may also include additional layers, some of which are disclosed in detail below or above. For example, as disclosed in some exemplary embodiments above, the sheath may also include a braid or coil disposed between the inner liner and the outer layer, and / or a braid or coil embedded in the outer layer.

[0107] In the exemplary embodiment shown in FIGS. 21A-21B, the sheath does not include a braid or coil disposed along the length of the sheath between the inner liner and the outer layer or embedded in the outer layer.

[0108] As with other embodiments of the sheath, the exemplary sheath of Figures 21A-21B can have an inner liner that has a variety of dimensions depending on the desired application and size of the delivery device and prosthesis. It is further understood that the inner liner is not limited to a particular shape or configuration. In certain embodiments, the sheaths disclosed herein have a resting diameter d r and outer diameter d o As disclosed herein, the static diameter d r The diameter may be defined by the inner liner, while the outer diameter may be defined by the inner liner and the outer layer.

[0109] Static diameter d of the inner liner 2102 r can vary depending on the application and size of the delivery device and prosthesis. The sheaths disclosed herein can have configurations similar to those illustrated in Figures 3A-3C and described above. In some embodiments, the resting diameter d, as shown in Figure 3B, can be r1 It will be appreciated that the rest diameter d is substantially uniform along the longitudinal axis of the lumen, without variation from the proximal end 308 to the distal end 306. In yet another embodiment, the rest diameter d r is the longitudinal axis of the lumen (e.g., d in FIG. 3A). r1 and d r2 , or d as shown in FIG. 3C r1 , d r2 , d r3 , and d r4) at the proximal end 304 or 312. r1 d at the distal end 302 or 310 r The static diameter d r2 Or as shown in FIG. 3C r4 In yet a further embodiment, the outer layer conforms to the shape of the inner liner and has an outer diameter d o (not shown) includes the overall diameter of the inner liner and outer layer. In such an embodiment, the outer diameter d o is determined by the specific application of the sheath. r Similarly, the outer diameter d of the non-expandable sheath disclosed herein o can be substantially uniform (constant) along the longitudinal axis of the lumen without varying from the proximal end to the distal end. In an alternative embodiment, the original unexpanded outer diameter d of the disclosed sheaths can be o is the static diameter d r Similarly, the static diameter d may decrease from the proximal end to the distal end. r Similarly, the original unexpanded outer diameter may decrease along a gradient from the proximal end to the distal end, or may have a largest original unexpanded outer diameter d o , and the smallest original unexpanded outer diameter d near the distal end o The sheath may be tapered incrementally along its length, having a thickness of 0.1 mm.

[0110] In some embodiments, similar to other sheath configurations disclosed herein, the sheath has a resting diameter d as shown in FIGS. r can also range from about 0.005 inches to about 0.400 inches, with exemplary values ​​of about 0.01, about 0.02, about 0.03, about 0.04, about 0.05, about 0.06, about 0.07, about 0.08, about 0.09, about 0.1, about 0.2, and about 0.3 inches. As noted above, in certain embodiments, the sheath can have various d r In such an embodiment, the inner liner may have a rcan have any value between any two of the aforementioned values ​​and may depend on the particular application and the size and shape of the delivery device and prosthesis. Depending on the size requirements of the delivery device for various applications, different sheaths may have different expanded and unexpanded resting diameters d r and outer diameter d o Additionally, some embodiments may provide more or less expansion depending on the particular design parameters, materials, and / or configurations used.

[0111] 22A-22B illustrate the expansion process of an exemplary sheath, such as that shown in FIGS. 21-21B. A sheath 2202, such as that shown in FIG. 22A, can be expanded from a collapsed configuration to an expanded configuration 2204 during passage of a medical device by sliding a first longitudinal edge and a second longitudinal edge along one another, reducing the overlap of the spiral configuration. Again, the expanded diameter d e may depend on the diameter of the medical device being passed. In still further embodiments, as discussed in detail below, the outer layer may provide an inward radial force on the inner liner to hold the sheath in place after the medical device has passed through the lumen. r 22B shows sequential instantaneous images of sheath expansion during passage of an exemplary medical device.

[0112] Additional embodiments of the sheath are disclosed in Figures 24A-24B. For example, Figure 24A shows an inner liner of a sheath having a configuration similar to that of the sheath disclosed in Figure 22, with a first end 2404 and a second end 2406 substantially aligned in a spaced apart relationship along a vertical axis 2420 passing through the thickness of the sheath. In such a configuration, a portion of the sheet 2403 is positioned between the first edge and the second edge along the vertical axis. As can be seen in Figure 24A, when the inner liner 2402 is in a non-expanded resting state, the inner liner includes at least two layers of sheets overlapping each other along at least a portion of the circumference of the sheath. Also, as seen in Figure 24, the inner liner can include at least two layers of sheets overlapping each other along the entire circumference of the sheath.

[0113] 24B illustrates different configurations of the liner in an expanded state. For example, when the liner 2402 is in a non-expanded, resting state, the inner liner can include a portion along the periphery of a sheath that can have three layers of sheet 2430.

[0114] 22A, there are also configurations of inner liners where a first edge 2204 is substantially aligned with a vertical axis 2420 passing through the thickness of the sheath and a second edge 2406 is circumferentially offset from the vertical axis. In such embodiments, along at least a portion of the circumference of the sheath, the inner liner comprises one layer of sheet without any overlapping portions.

[0115] Additional configurations of the sheath are also shown in Figures 31-32. Some of the sheath configurations disclosed above are formed by providing an elongated tube and cutting the tube along its length to form a sheet having a first longitudinal edge and a second longitudinal edge. The sheet is formed by forming a slit. In various configurations, the particular type of slit can be formed depending on the final desired application. For example, for various sheath configurations disclosed above, as shown, for example, in Figure 9A, the slit 905 is substantially straight along the length of the tube forming the inner liner. In such exemplary embodiments, the slit formed during cutting is substantially straight from the proximal end of the inner liner to the distal end of the inner liner. In such embodiments, the spiral configuration formed when the sheet is wound into a scroll is substantially straight along the length of the sheath.

[0116] However, embodiments are also disclosed herein in which the inner liner is wound in a spiral scroll configuration. An exemplary diagram of such a configuration is shown in FIG. 32. In such embodiments, an elongated tube forming the inner liner 915 is provided and cut such that longitudinal slits 911 are formed between the proximal and distal ends of the tube, forming first and second longitudinal edges of the tubular inner liner 915 (FIG. 31). As shown in FIG. 31, for example, the slits in these embodiments are not formed along the longitudinal axis of the liner, but are at least somewhat offset therefrom. The slits are formed such that the inner liner is wound in a spiral scroll configuration such that at least a portion of the inner surface of the inner liner 915b helically overlaps at least a portion of the outer surface 915a of the inner liner in the spiral scroll configuration (the overlap is not shown in FIG. 31). The overlapping portion 913 can be seen in FIG. 32. In a still further aspect, in this spiral sheath configuration, a first longitudinal edge of the inner liner is slidable along at least a portion of an inner surface of the inner liner and a second longitudinal edge is slidable along at least a portion of an outer surface of the inner liner.

[0117] In such exemplary embodiment, the tubular inner liner also has a static diameter d by sliding a first edge of the inner liner helically along at least a portion of the inner surface and sliding a second edge of the inner liner helically along at least a portion of the outer surface of the inner liner during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r From expansion diameter d e The system is configured to extend

[0118] When a sheath is inserted into a patient, for example, through the femoral artery, and passes along an arterial pathway, the arterial pathway can often be a twisted and tortuous path, forcing the sheath to assume a curved configuration along it. Furthermore, when a larger diameter prosthetic valve (or any other prosthesis that can be advanced through the sheath) passes through the sheath, the combination of the expansion force and the curved configuration of the sheath can result in the layers of the sheath potentially splitting the longitudinal edges, which can cause the formation of an undesirable gap between the two longitudinal edges. A sheath having a helical configuration can avoid this potentially undesirable effect. In some aspects, the exemplary helical configuration of the sheath can allow for the expansion of the inner liner with substantially no gap formed between the longitudinal edges of the inner liner defined by the slits. Further in these exemplary aspects, the tubular inner liner of the disclosed sheath is configured to bend while passing through the natural anatomy of the patient without forming a gap between the first longitudinal edge and the second longitudinal edge of the tubular inner liner.

[0119] It is understood that the divisions may be formed in any orientation that allows for a helical configuration of the scroll. For example, and without limitation, in some aspects, the longitudinal slits may extend in a direction offset from the longitudinal axis of the tubular inner liner from the proximal end of the tubular inner liner to the distal end of the tubular inner liner. In still further aspects, the direction is diagonal from the proximal end of the tubular inner liner to the distal end of the tubular inner liner. In still yet further embodiments, the longitudinal slit extends from the proximal end of the tubular inner liner across the length of the tubular inner liner to the distal end of the tubular inner liner at an angle of greater than about 90 degrees, e.g., about 100 degrees, about 110 degrees, about 120 degrees, about 130 degrees, about 140 degrees, about 150 degrees, about 160 degrees, and about 170 degrees, or less than about 90 degrees, e.g., about 80 degrees, about 70 degrees, about 60 degrees, about 50 degrees, about 40 degrees, about 30 degrees, about 20 degrees, and about 10 degrees.

[0120] In still further aspects, the longitudinal slits may be formed between the proximal end of the tubular inner liner and the distal end of the tubular inner liner in a pattern other than a straight line. For example, but not limited to, the slits may be formed to allow for the formation of a particular pattern of the sheet. For example, in such aspects, the first and second longitudinal edges do not have a substantially straight line. In some aspects, the slits may be formed such that each of the first and second longitudinal edges may have a zigzag configuration or may have an angle greater than or less than 180 degrees or 0 degrees. For example, each of the edges may have a protruding and corresponding recessed shape, or a concave and corresponding convex shape, a curved shape, etc., depending on the orientation of the slits. Again, it is understood that any orientation of the slits that can form a spiral scroll configuration of the inner liner is contemplated and described.

[0121] In still further aspects, the slits can be formed such that the helical configuration of the inner liner has a predetermined pitch, hi certain aspects, the pitch can be at least about 2 turns, at least about 3 turns, at least about 4 turns, at least about 5 turns, or at least about 6 turns per 10 cm of the sheath.

[0122] In still further aspects, the rest diameter d of this exemplary sheath r and expansion diameter d e can be similar to any of those described in the previous embodiments.

[0123] In still further aspects, the tubular inner liner having a spiral scroll configuration, as well as other sheath configurations, can include high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof. In further aspects, the inner liner can have a multi-layer construction, as disclosed in other configurations. In some aspects, the inner surface of the inner liner can be substantially smooth, while in other aspects, the inner surface of the tubular inner liner can be at least partially ribbed. In still further aspects, the tubular inner liner can be lubricious and 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, or less than about 0.1.

[0124] An additional configuration of the sheath is also shown in Figure 33. In this embodiment, the variable diameter inner liner 3300 comprises a sheet 3302 having a first longitudinal edge 3302a and a second longitudinal edge 3302b. The sheet is wound in a spiral 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 forming an overlapping portion, as shown in Figure 33, and at least a portion of the outer surface of the sheet abutting the first longitudinal edge 3302a includes a first plurality of protrusions 3320. In still a further embodiment, at least a portion of the first plurality of protrusions are disposed within the overlapping portion, thereby reducing the contact area between the inner and outer surfaces of the sheet within the overlapping portion.

[0125] In yet a further aspect, in the disclosed spiral configuration of the inner liner, a first longitudinal edge 3302a of the sheet is slidable along at least a portion of the inner surface of the sheet and a second longitudinal edge 3302b is slidable along at least a portion of the outer surface of the sheet.

[0126] However, it is understood that the plurality of protrusions may be present on the inner surface of the sheet in addition to or instead of the outer surface. In such an embodiment (not shown), the second plurality of protrusions 3320 may also be disposed on the inner surface abutting at least the second longitudinal edge 3302b. It is also understood that the first and second plurality of protrusions may be the same or different. In such an exemplary embodiment, for example, the composition of the first and second plurality of protrusions may be the same while the shapes are different. Other exemplary embodiments are also envisioned that include first and second plurality of protrusions that are different in both composition and shape, or that are different in both composition and shape.

[0127] In a still further aspect, the inner surface of the sheet defines a lumen of a sheath having a longitudinal axis.

[0128] In still yet a further aspect, the variable diameter inner liner is configured to have a first resting diameter d by sliding a first edge of the sheet along at least a portion of the inner surface and sliding a second edge of the sheet along at least a portion of the outer surface during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r to the second expansion diameter d e The system is configured to extend

[0129] In still further embodiments, the sheet is wound to form a spiral having three or fewer radial sections of predetermined thickness and a smaller portion having only one radial thickness. In certain embodiments, when a medical device passes through an expandable variable diameter inner liner, the applied radial force is large and any friction or sticking between the sliding parts will undesirably increase the pushing force.

[0130] In still further embodiments, the sheet has a predetermined thickness. In such embodiments, the sheet can have any thickness between about 0.002 inches and about 0.025 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 of any configuration disclosed herein can be varied depending on the desired amount of radial expansion, as well as the strength required.

[0131] In still further aspects, the first and / or second plurality of protrusions may be arranged in any possible arrangement or pattern suitable for a desired application on the inner and / or outer surface of the sheet. In some aspects, the first and / or second plurality of protrusions may be arranged in a predetermined pattern to reduce the contact area between the inner and outer surfaces of the sheet in the overlapping portion. It is understood that reduced contact may be useful during the expansion procedure because the two portions do not stick to each other, thus reducing the pushing force required to pass a medical device through the sheath.

[0132] In still further aspects, the first and / or second plurality of protrusions may have any shape that allows for achieving a desired result. In certain aspects, the first and / or second plurality of protrusions may include a regular shape, such as a continuous stripe along the length of the inner liner, or a discontinuous pattern of discontinuous circular shaped protrusions, rectangles, diamonds, trapezoids, etc. In yet other aspects, the shape may be irregular, such as a star shape or any other shape. In yet other aspects, the plurality of protrusions may have a combination of various shapes.

[0133] In still further aspects, the first and / or second plurality of protrusions may have an average height of up to about 1%, about 5%, about 10%, about 15%, or about 20% of the predetermined thickness of the sheet itself. It is understood that in some aspects, each of the first and / or second plurality of protrusions need not have the same height. In yet other aspects, the first and / or second plurality of protrusions may have substantially the same height.

[0134] In still further aspects, the sheet comprises a first polymer composition. In such aspects, the first polymer composition can comprise high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof. Meanwhile, in still further aspects, the sheet can comprise a multi-layer structure. In aspects where there are two or more layers, each layer can comprise the same material or different materials.

[0135] In yet further embodiments, the first and / or second plurality of protrusions may comprise a second polymer composition. Again, it is understood that the second polymer composition may be the same or different from the first polymer composition depending on the particular application. Again, it is understood that the first and / or second plurality of protrusions may be disposed on the outer surface and / or the inner surface of the sheet, respectively. In embodiments where there are first and second plurality of protrusions, the second plurality of protrusions present on the inner surface may be the same or different from the first plurality of protrusions present on the outer surface of the sheet. In embodiments where the second polymer composition is different from the first polymer composition, it is understood that these two compositions are compatible with each other and can be bonded together.

[0136] In still further aspects, it is understood that the portion of the sheet that includes the first plurality of protrusions and / or the second plurality of protrusions is not limited to the overlapping portion.

[0137] In some embodiments, at least a portion of the sheet having the first and / or second plurality of protrusions may be larger than the overlapping portion. In still further embodiments, at least a portion having the first and / or second plurality of protrusions is substantially the same as the circumference of the sheet in the spiral configuration. In such embodiments, it is understood that the first and / or second plurality of protrusions are disposed across the entire outer and / or inner surface of the sheet, respectively.

[0138] In still other aspects, the first and / or second plurality of protrusions may be disposed on the outer and / or inner surface of the sheet, respectively, along at least a portion of the length of the sheath, while in other aspects, the first and / or second plurality of protrusions may be disposed on the outer and / or inner surface of the sheet, respectively, that abuts the distal end of the sheath, while in still further aspects, the first and / or second plurality of protrusions may be disposed on the outer and / or inner surface of the sheet, respectively, that abuts the proximal end of the sheath, while in still further aspects, the first and / or second plurality of protrusions may be disposed on the outer and / or inner surface of the sheet, respectively, along the entire length of the sheath.

[0139] It is further understood that in some exemplary embodiments, the first and / or second protrusions can have various shapes as disclosed above, and these shapes can be continuous or completely discontinuous along at least a portion of the length of the inner member. The size of each of the first and / or second protrusions can vary depending on the desired application. In still further embodiments, the average size of the first and / or second protrusions can be less than about 50%, less than about 40%, less than about 30%, less than about 20%, less than about 10%, or even less than about 5% of a given thickness of the sheet.

[0140] As with other sheath configurations, this sheath configuration has a static diameter d r may be substantially uniform along the longitudinal axis of the lumen, or may vary along the longitudinal axis of the lumen.

[0141] In some embodiments, the inner surface of the inner liner can be substantially smooth, while in other embodiments, the inner surface of the tubular inner liner can be at least partially ribbed, and in still further embodiments, the tubular inner liner can be lubricious and 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, or less than about 0.1.

[0142] Additional configurations of the sheath are also shown in FIG. 34. In this embodiment, the variable diameter inner liner 3400 comprises a sheet 3402 having a first longitudinal edge 3402a and a second longitudinal edge 3402b. The sheath inner liner 3400 has an inner surface 3403a and an outer surface 3405a. As shown in FIG. 34, the sheet is wound in a spiral configuration such that at least a portion of the inner surface 3403b of the sheet covers at least a portion of the outer surface 3405b of the sheet forming the overlap. As further shown in FIG. 34, at least a portion of the outer surface 3405a of the sheet can include a plurality of bond sites 3420 at least partially embedded within the sheet. As illustrated in FIG. 34, these plurality of bond sites 3420 are arranged such that the outer surface 3405b of the sheet within the overlap is substantially free of these bond sites.

[0143] In yet a further aspect, in the disclosed spiral configuration of the inner liner, a first longitudinal edge 3402a of the sheet is slidable along at least a portion of the inner surface of the sheet and a second longitudinal edge 3402b is slidable along at least a portion of the outer surface of the sheet.

[0144] In still further embodiments, the sheet has a predetermined thickness. In such embodiments, the sheet may have any thickness between about 0.002 inches and about 0.025 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 of any configuration disclosed herein may be varied depending on the desired amount of radial expansion, as well as the strength required. In such embodiments, the multiple bond sites shown in the exemplary sheath of FIG. 34 may have a depth (depth of bond sites embedded within the sheet itself) of about 50% or less of any of the predetermined values ​​of sheet thickness disclosed above. For example, the depth of the bond sites can be about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 15% or less, about 10% or less, or about 5% or less of the given thickness disclosed above.

[0145] In still further embodiments, the bond sites are disposed on the outer surface and are not embedded or are only partially embedded within the sheet. In such embodiments, the bond sites may also extend at least partially from the outer surface of the sheet. In such exemplary embodiments, the extensions of the bond sites may have a height of about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 15% or less, about 10% or less, or about 5% or less of the predetermined thickness disclosed above. In still further embodiments in which the bond sites extend from the outer surface of the sheet and are at least partially embedded within the sheet, the height and depth of the bond sites are about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 15% or less, about 10% or less, or about 5% or less of the predetermined thickness disclosed above.

[0146] In still further aspects, the plurality of bond sites may have an average depth of up to about 1%, up to about 5%, up to about 10%, up to about 15%, up to about 20%, up to about 25%, up to about 30%, up to about 35%, up to about 40%, up to about 45%, or up to about 50% of the predetermined thickness of the sheet itself. In still further aspects, the plurality of bond sites may have an average depth and average height when at least a portion of such bond sites extends above the outer surface up to about 1%, up to about 5%, up to about 10%, up to about 15%, up to about 20%, up to about 25%, up to about 30%, up to about 35%, up to about 40%, up to about 45%, or up to about 50% of the predetermined thickness of the sheet itself.

[0147] In embodiments where multiple bond sites are embedded within the sheet and extend above the exterior surface, the depths and heights of such bond sites may be the same or different depending on the particular application. In still further embodiments, the depths and / or heights of each of the bond sites in a plurality of bond sites may likewise be the same or different.

[0148] In yet further embodiments, the sheet comprises a first polymer composition. In such embodiments, the first polymer composition may comprise high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof. Meanwhile, in still further embodiments, the sheet may comprise a multi-layer structure. In embodiments where there are two or more layers, each layer may comprise the same material or different materials.

[0149] In still further aspects, the plurality of bond sites may comprise a second polymer composition. In such aspects, the second polymer composition is different from the first polymer composition. However, it is understood that the first and second polymer compositions may also be substantially the same, as desired, depending on the particular application. In still further aspects, the second polymer composition comprises polyethylene, polypropylene, graft modified polyethylene or polypropylene, or a combination thereof. In some exemplary aspects, the second polymer composition may comprise grafted low density polyethylene (LDPE), grafted medium density polyethylene, grafted very 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.

[0150] For example, but not limited to, the sheets may comprise HDPE while the bond sites may comprise LDPE or a terpolymer such as a maleic anhydride modified polyolefin, for example, but not limited to, ethylene acrylic acid copolymers such as Orevac® (available from Arkema), DOW Chemical Primacor®, ethylene acrylate copolymers such as Lotryl® (available from Arkema), ethylene glycidyl methacrylate copolymers, ethylene acrylic ester glycidyl methacrylate terpolymers such as Lotader® (available from Arkema), ethylene acrylic ester maleic anhydride terpolymers such as Lotader® or Orevac® (available from Arkema), or combinations thereof.

[0151] In yet a further embodiment, the first polymer composition and the second polymer composition may be coextruded together to form the inner liner. In embodiments where the second polymer composition is different from the first polymer composition, it is understood that the two compositions are compatible with each other and will not delaminate.

[0152] In still further aspects, the bond sites can be disposed along at least a portion of the length of the inner liner. In still further aspects, the bond sites can be disposed along the entire length of the inner liner, while in other aspects, the bond sites can be disposed on the outer surface of the sheet that abuts the distal end of the sheath (not within the overlapping portion). In still further aspects, the bond sites can be disposed on the outer surface of the sheet that abuts the proximal end of the sheath (not within the overlapping portion).

[0153] In aspects, the multiple bond sites are arranged in a predetermined pattern to allow for bonding with the outer layer and to prevent axial movement of the outer layer during passage of a medical device through the lumen of the inner liner, hi still further aspects, the pattern can be any pattern desired for a particular application to allow for bonding with the outer layer.

[0154] In some aspects, the plurality of bond sites are arranged in a predetermined pattern to bond the inner liner to the outer layer without impairing expansion of the inner liner upon passage of a medical device. It is understood that because expansion can be achieved by sliding the first and second longitudinal edges and reducing the overlap, the bond sites are not located within the overlap to avoid undesirable binding and restriction in sliding.

[0155] In still further aspects, the multiple bond sites may have any desired shape. For example, but not limited to, the multiple bond sites may have regular shapes, irregular shapes, or any combination thereof. In certain aspects, the multiple bond sites may include regular shapes, such as continuous stripes along the length of the inner liner, or discontinuous shapes, such as discontinuous circular shapes, rectangular shapes, diamond shapes, trapezoidal shapes, and the like. Again, it is understood that the multiple bond sites may be at least partially embedded within the sheet, or may be fully embedded within the sheet, or may extend at least partially above the outer surface of the sheet. In any of these aspects, the shape of each of the multiple bond sites may be the same or different, or may be any variation of shape.

[0156] In still further embodiments, each of the plurality of bond sites has a width that is about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 15% or less, about 10% or less, or about 5% or less of the predetermined thickness disclosed above, while in still other embodiments, each of the plurality of bond sites has a width that is up to about 1%, up to about 5%, up to about 10%, up to about 15%, up to about 20%, up to about 25%, up to about 30%, up to about 35%, up to about 40%, up to about 45%, or up to about 50% of the predetermined thickness disclosed above.

[0157] In yet other embodiments, each of the plurality of bond sites has a width that is about 1X to about 10X the thickness of the plurality of bond sites, with exemplary values ​​of about 2X, about 3X, about 4X, about 5X, about 6X, about 7X, about 8X, and about 9X the thickness of the plurality of bond sites.

[0158] In still further embodiments, each of the plurality of bond sites has a width of about 0.01 inches to about 0.15 inches, including exemplary values ​​of about 0.015 inches, about 0.02 inches, about 0.025 inches, 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 0.1 inches, about 0.11 inches, about 0.12 inches, about 0.13 inches, and about 0.14 inches.

[0159] In still further aspects, the plurality of junction sites may include one junction site, while in other aspects, the plurality of junction sites includes at least two junction sites. It is understood that the number of junction sites may be specifically selected depending on the desired application. It is further understood that each of the plurality of junction sites may be located at a predetermined distance from each other, and this predetermined distance may be selected depending on the desired application. In still further aspects, the number and location of the junction sites may be selected to provide adequate anchor strength to allow sections of the outer jacket to expand as the inner member expands, but to substantially prevent axial movement of the outer jacket (elastic outer component) relative to the inner member during insertion and withdrawal of the sheath from the body, and during passage of the medical device.

[0160] In still further embodiments, instead of being disposed on the outer surface of the inner layer (liner) of the sheath, any of the disclosed bond sites may be disposed on the inner surface of the outer layer (outer jacket) of the sheath. In such exemplary embodiments, the inner liner may not include any bond sites, while the inner surface of the outer layer may include one or more bond sites, as shown, for example, in FIGS. 43A-43B. For example, the inner liner of such embodiments may have any of the thicknesses disclosed above. As disclosed below, the outer layer may also have a predetermined thickness. For example, the predetermined thickness of the outer layer may vary along the length of the sheath, while in other embodiments, the predetermined thickness of the outer layer is the same along the length of the sheath. And in further embodiments, the predetermined thickness of the outer layer is greater at the proximal end. In still further embodiments, the predetermined thickness of the outer layer is up to 0.015 inches, for example, but not limited to, about 0.001 inches to about 0.015 inches, about 0.0015 inches, about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, about 0.0055 inches, about 0.006 inches, about 0.00 Exemplary values ​​include about 65 inches, about 0.007 inches, about 0.0075 inches, about 0.008 inches, about 0.0085 inches, about 0.009 inches, 0.0095 inches, about 0.01 inches, about 0.0105 inches, about 0.011 inches, about 0.01105 inches, about 0.012 inches, about 0.01205 inches, about 0.013 inches, about 0.01305 inches, about 0.014 inches, and about 0.01405 inches.

[0161] An enlargement 4300 of the bond site is shown in Figure 43B. It can be seen that the outer layer can have one or more bond sites having a width w. In such embodiments, the width can have any value between about 0.01 inches and about 0.15 inches, including exemplary values ​​of about 0.015 inches, about 0.02 inches, about 0.025 inches, about 0.03 inches, 0.035 inches, about 0.04 inches, 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 0.1 inches, about 0.11 inches, about 0.12 inches, about 0.13 inches, and about 0.14 inches.

[0162] In still yet further embodiments, the bond site may have a thickness having any value between 0.0001 inches and about 0.005 inches, including exemplary values ​​of about 0.0002 inches, about 0.0003 inches, about 0.0004 inches, about 0.0005 inches, about 0.0006 inches, about 0.0007 inches, about 0.0008 inches, about 0.0009 inches, about 0.001 inches, about 0.0015 inches, about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, and about 0.0045 inches.

[0163] Any of the materials used to form the inner liner, outer layer (outer jacket), and bond sites disclosed herein may be utilized without limitation. It is further understood that the bond sites disposed on the inner surface of the outer layer (outer jacket) may have the same shape as the bond sites disposed on the outer surface of the inner liner as disclosed above. Any of the properties or characteristics of the bond sites disposed on the outer surface of the inner liner are applicable to the bond sites disposed on the inner surface of the outer jacket.

[0164] For example, and without limitation, the bond sites may be disposed on the inner surface of the outer jacket and may not be embedded or may only be partially embedded within the outer jacket. If the outer jacket is comprised of more than one polymer layer, it will be understood that the bond sites may be embedded within any or all of the polymer layers present within the outer jacket. In yet other embodiments, the bond sites may include a polymer capable of replacing at least a portion of at least one polymer layer in place.

[0165] In embodiments where multiple bond sites are embedded in the outer jacket and extend above its inner surface, the depths and heights of such bond sites may be the same or different depending on the particular application. In still further embodiments, the depths and / or heights of each of the bond sites in a multiple bond site may likewise be the same or different.

[0166] In a still further aspect, the inner surface of the sheet defines a lumen of a sheath having a longitudinal axis.

[0167] In still yet a further aspect, the variable diameter inner liner is configured to have a first resting diameter d by sliding a first edge of the sheet along at least a portion of the inner surface and sliding a second edge of the sheet along at least a portion of the outer surface during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r to the second expansion diameter d e The system is configured to extend

[0168] In still further embodiments, the sheet is wound to form a spiral having three or fewer radial sections of predetermined thickness and a smaller portion having only one radial thickness. In certain embodiments, when a medical device passes through an expandable variable diameter inner liner, the applied radial force is large and any friction or sticking between the sliding parts will undesirably increase the pushing force.

[0169] As with other sheath configurations, this sheath configuration has a static diameter dr may be substantially uniform along the longitudinal axis of the lumen, or may vary along the longitudinal axis of the lumen.

[0170] In some embodiments, the inner surface of the inner liner can be substantially smooth, while in other embodiments, the inner surface of the tubular inner liner can be at least partially ribbed, and in still further embodiments, the tubular inner liner can be lubricious and 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, or less than about 0.1.

[0171] In still yet further aspects, a sheath having an inner liner embodiment disclosed herein may further include any of the outer layers, braids, tie layers, lubricants, etc. disclosed herein.

[0172] Additional configurations of the inner liner are also depicted in Figure 18. Figure 18 shows an inner liner 1800 comprising a sheet wound in a spiral configuration, the sheet comprising a first portion 1802 having a first surface 1802a and an opposing second surface 1802, a first end 1804 of the first portion 1802 divided into a first segment 1806 having a first surface 1806a and an opposing second surface 1806b and a third segment 1808 having a first surface 1808a and an opposing second surface 1808b, and a second end of the first portion extending into a second segment 1810 having a first surface 1810a and an opposing second surface 1810b.

[0173] 18, in the spiral configuration, at least a portion of the first surface 1810a of the second segment 1810 overlaps with at least a portion of the second surface 1806b of the first segment 1806, at least a portion of the first surface 1808a of the third segment 1808 overlaps with at least a portion of the second surface 1810b of the second segment 1810, and at least a portion of the first surface 1808a of the third segment overlaps with at least a portion of the second surface 1806b of the first segment 1806. It may also be seen that the first surface 1804a of the first portion 1804 extends into the first surface 1806a of the first segment 1806, the first surface 1810a of the second segment 1810, and the first surface 1808a of the third segment 1808. It can also be seen that the second surface 1804b of the first portion 1804 extends into the second surface 1810b of the second segment 1810 and into the second surface 1808b of the third segment 1808. Each of these segments can slide along one another during passage of a medical device to expand the sheath.

[0174] FIG. 19 shows an exemplary sheath having an inner liner 1800 as shown in FIG.

[0175] Referring again to FIG. 18, when at least a portion of the first surface 1810a of the second segment 1810 overlaps with at least a portion of the second surface 1806b of the first segment 1806, a first gap 1812 is formed between at least a portion of the first surface 1810a of the second segment 1810 and at least a portion of the second surface 1804b of the first segment 1806.

[0176] Furthermore, a second gap 1814 can be formed when at least a portion of the first surface 1808a of the third segment 1808 overlaps with at least a portion of the second surface 1810b of the second segment 1810. Still further, a third gap 1816 can be formed when at least a portion of the first surface 1808a of the third segment 1808 overlaps with at least a portion of the second surface 1806b of the first segment 1806.

[0177] It is understood that the first gap may have a substantially uniform width along the overlapping portion, or the width may vary. Similarly, the second gap may have a substantially uniform width along the overlapping portion, or the width of the second gap may vary along the overlapping portion. Still further, the third gap may have a substantially uniform or variable width along the overlapping portion. In still further aspects, the width between the gaps may be any width as desired. For example, it is understood that the width of each of the three gaps may be the same or different. In certain aspects, the widths of some of the gaps are the same while the widths of others are different.

[0178] When a sheath such as that disclosed in FIGS. 18 and 19 is utilized, upon passage of a medical device through the lumen, the first segment 1806, the second segment 1810, and the third segment 1808 are configured to slidably move along one another such that the overlap between the first segment and the second segment and between the second segment and the third segment decreases, while the overlap between the first segment and the third segment increases.

[0179] As with any of the sheath configurations disclosed herein, the diameter of the lumen of the sheath shown in FIG. 19 is a first rest diameter d r to the second expansion diameter d eAfter passage of a medical device through the lumen, the first segment 1806, the second segment 1808, and the third segment 1810 are configured to slidably move back along one another such that the overlap between the first and second segments, the second and third segments, and the first and third segments increases. After passage of the device, the diameter of the lumen increases to a second expanded diameter d e From the first static diameter d r 4. The diameter of the first hole 14 is reduced to a diameter substantially the same as that of the first hole 14.

[0180] As disclosed above, d r It is further understood that the d may be uniform along the length of the sheath or may vary from the proximal end of the sheath to the distal end of the sheath, as shown in Figures 3A-3C. r It is further understood that any value of is also applicable to the sheath configurations, as shown in FIGS.

[0181] During a transcatheter aortic valve replacement (TAVR) procedure, the sheaths disclosed herein are used to provide atraumatically access to the vasculature of the patient, acting to maintain hemostasis and facilitate delivery of interventional devices and exchange of wires and catheters. To keep the sheath as minimally invasive as possible, it must have a low profile, or small outer diameter (OD), upon entry. However, the sheath must expand to a larger diameter once inside the body to allow passage of a catheter larger than the initial diameter of the sheath. The force that advances these devices through the sheath is commonly referred to as the pushing force. With larger devices, such as crimped valves on the delivery system (DS), and challenging vascular anatomies, such as small, tortuous, or stenosed vessels, the pushing force during the procedure is very important. High pushing forces can cause delays in the procedure, physician dissatisfaction, and even failure to complete the procedure.

[0182] An important function of the sheath is to have a clinically acceptable pushing force to advance the delivery system and valve through the sheath for all patient anatomy. In some embodiments, lubrication is used to aid in this reduction of pushing force. Lubrication is placed between the layers that slide over each other and reduces the frictional forces that must be overcome to expand the sheath, thus making it easier for the DS to pass through the sheath. Recent studies have shown that lubrication is necessary to reduce the pushing force to an acceptable level.

[0183] Still further, the sheath configurations disclosed herein can include a lubricant. One exemplary embodiment of a sheath 2300 is shown in FIG. 23. In this configuration, for example, a lubricant 2306 can be disposed between the inner liner 2302 and the outer layer 2304.

[0184] For sheaths having the configurations shown in Figures 18 and 19, lubricant may be disposed between any portion and segment in any amount and in any combination. In certain exemplary and non-limiting aspects, lubricant may be disposed between the first and second segments, or between the second and third segments, or between the first and third segments, or any combination thereof. In yet other aspects, lubricant may be disposed such that it is located on the innermost surface of the sheath, or the outermost surface of the sheath, or a combination thereof.

[0185] In still further aspects, the lubricant may be disposed along the entire periphery of the inner liner or may be disposed between at least a portion of the overlapping portion of the sheet and at least a portion of the sliding portion of the sheet.

[0186] Still further, the lubricant may be disposed along at least a portion of an inner surface of the sheet, or at least a portion of an outer surface of the sheet, or a combination thereof.

[0187] Any lubricant known in the art may be utilized. In yet further embodiments, the lubricant may include a PTFE-based lubricant or a silicone-based lubricant. In specific, non-limiting embodiments, the lubricant may include Christo Lube from ECL, or MED10 / 6670 or PRO-3499 from Nusil, or PRO-3595, also from Nusil. In still further embodiments, it is understood that the amount of the first and / or second lubricant may be readily determined by one of ordinary skill in the art.

[0188] Further, in certain embodiments, the lubricant may be disposed in a predetermined pattern, for example, as shown in Figure 26. In such embodiments, the lubricant is disposed on the inner liner 2602, for example, in a pattern 2609. It will be understood that the pattern 2609 is merely exemplary, and that any desired pattern for any particular application may be applied.

[0189] The lubricant can be applied in any manner, for example, it can be applied manually, where the lubricant is brushed onto the sheath by hand, making it difficult to precisely control how much lubrication is applied to the sheath and exactly where the lubrication is applied to the sheath.

[0190] Thus, as disclosed herein, the lubricant can also be applied by pad printing or spraying, which allows the material to be applied in a precisely controlled, repeatable manner, suitable for large scale manufacturing. Details of the methods of lubricant application are described below.

[0191] However, in embodiments in which the lubricant is applied by pad printing, it is understood that the lubricant, prior to its application, has a viscosity of about 600 to about 1,200 cP, including exemplary values ​​of about 650 cP, about 700 cP, about 750 cP, about 800 cP, about 850 cP, about 900 cP, about 950 cP, about 1,000 cP, about 1,050 cP, about 1,100 cP, and about 1,150 cP.

[0192] On the other hand, in embodiments in which the lubricant is sprayed, the lubricant may have a viscosity of about 600 cP or less, or about 550 cP, about 500 cP, about 450 cP, about 400 cP, about 350 cP, or about 350 cP or less.

[0193] In a still further aspect, the lubricant is cured prior to positioning the outer layer onto the inner liner of the sheath.

[0194] The lubricant may also form a film. If a film of the lubricant is formed, such film may have a thickness of about 20 micrometers or less, about 15 micrometers, about 10 micrometers, about 5 micrometers, about 1 micrometer, or even about 0.5 micrometers or less.

[0195] In yet a further aspect, the inner liner of any configuration disclosed herein may comprise a polyolefin, a polyamide, a fluoropolymer, a copolymer thereof, or a mixture thereof. In yet a further aspect, the polyolefin may comprise a high density polyethylene, a polypropylene, or a mixture thereof.

[0196] In still further aspects, the sheet can comprise one or more layers. In still further aspects, the sheet can have a multi-layer structure. In some aspects, when one or more layers are present, each layer can comprise the same or different polymers. In still further aspects, the sheet can have a predetermined thickness, which can be defined by one skilled in the art depending on the specific application. In certain aspects, the predetermined thickness of the inner liner can be about 0.002 inches to about 0.025 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 of any configuration disclosed herein can be varied depending on the desired amount of radial expansion, as well as the strength required.

[0197] In certain aspects, the inner liner of any of the sheath configurations described herein may include a compound material. For example, the polymer layer of the sheet used to form the inner liner may include a compound material including a polyolefin and a lubricious filler. It is understood that any of the polyolefins described above may be used. In some exemplary aspects, the polyolefin used in the compound material is high density polyethylene. In still other aspects, the lubricious filler may be any filler that can improve the lubricity of the polymer layer and reduce the overall coefficient of friction of the liner. In some exemplary and non-limiting aspects, the lubricious filler may include any additive known to reduce friction and behave as a lubricant. In these exemplary and non-limiting aspects, the lubricious filler may include one or more of graphene, reduced graphene oxide, carbon black, boron nitride, silicone, talc, polytetrafluorethylene (PTFE), fluorinated ethylene propylene, and the like. In still further aspects, the lubricious filler includes a PTFE filler. In still further aspects, the PTFE filler is a powder.

[0198] In still further embodiments, the lubricating filler can be present in any amount. In some exemplary and non-limiting embodiments, the lubricating filler can be present in an amount of about 5% to about 20% by weight of the total weight of the compound material used to make the polymeric layer of the inner liner. In still further embodiments, the lubricating filler can be present in an exemplary amount of about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, or about 20% by weight.

[0199] In still further embodiments, sheets comprising such compound materials may be lubricious and 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 sheets may have a coefficient of friction having any value between any two of the aforementioned values.

[0200] It is further understood that when the polymer layer of the sheet used to form the inner liner comprises a compound material as disclosed herein, the sheath may be substantially free of a separately disposed lubricant. For example, when the inner liner itself comprises a lubricating filler, a lubricant as disclosed above applied between overlapping portions of the inner liner or between the outermost surface of the inner liner and the innermost surface of the outer layer may not be required. However, also disclosed herein are sheath embodiments in which the inner liner comprises a lubricating compound in its composition, and a separate lubricant as disclosed above is still applied between various portions of the sheath. In such exemplary embodiments, this additional lubricant, applied manually, pad printed, or sprayed, may be applied between some portions of the inner liner and the outer layer, or all portions of the inner liner and the outer layer, as disclosed above. It is also understood that this additional lubricant may be applied in any desired pattern. It may also be applied along the entire length of the sheath, or only along some portions of the sheath. The lubricant may also be applied in different patterns in different portions of the sheath. And in other embodiments, the lubricant may be applied in the same pattern along various portions of the sheath.

[0201] In still further aspects, the inner surface of the sheet may be at least partially ribbed. In such exemplary aspects, the inner surface of the sheet may be at least partially ribbed prior to winding the sheet into a spiral configuration to form the inner liner.

[0202] In some aspects, a sheath described herein that includes a lubricious material in the inner liner can exhibit a pushing force required to move a prosthesis through the sheath that is comparable to or even less than the pushing force of a substantially identical reference sheath wound in a spiral configuration, the inner liner of which includes a polymer layer that is substantially free of lubricious fillers and includes an amount of lubricant disposed between overlapping portions of the spiral configuration and / or the outermost surface of the inner liner. In other words, in some aspects, when the performance of any sheath configuration disclosed herein is compared, in these exemplary and non-limiting aspects, a sheath having a lubricious material in the inner liner and no additional lubricant present can exhibit similar or even better performance than a similar sheath that does not have a lubricious material in the inner liner but has additional lubricant dispersed among various portions of the sheath.

[0203] In still further embodiments, the sheath may also include a tie layer, as described herein. In such embodiments, the tie layer may be disposed on the inner surface of the inner liner or on the outer surface of the inner liner, see, for example, FIGS. 25A-B. FIGS. 25A-B show an exemplary coextruded tube that may be used to form a sheet, which is then wound into a spiral configuration. Details of the method of forming the inner liner are described in more detail below. Here, FIGS. 25A-B show a coextruded tube 2502 including a polymer layer 2505 and a tie layer 2503. FIG. 25A shows that the tie layer 2503 is coextruded with the polymer layer 2505 such that the tie layer is positioned on the outer surface of the polymer layer. It will be understood that the outer surface of the polymer layer defines at least a portion of the outer surface of the inner liner when in the spiral configuration. FIG. 25B shows that the tie layer 2503 is coextruded with the polymer layer 2505 such that the tie layer is positioned on the inner surface of the polymer layer. It is understood that the inner surface of the polymeric layer defines at least a portion of the inner surface of the inner liner when in the spiral configuration.

[0204] It will be understood that the polymer layer 2505 can be any of the polymer layers described above and used to make the sheet, hi certain embodiments, the polymer layer can be high density polyethylene.

[0205] In yet further embodiments, the tie layer 2503 may comprise any material suitable for the desired application. It is understood that the tie layer may have adhesive or bonding properties. In certain embodiments, the tie layer may comprise a polyurethane material such as Tecoflex, or a polymer, copolymer, or terpolymer such as maleic anhydride modified polyolefin, for example, but not limited to, ethylene acrylic acid copolymers such as Orevac® (available from Arkema), DOW Chemical Primacor®, ethylene acrylate copolymers such as Lotryl® (available from Arkema), ethylene glycidyl methacrylate copolymers, ethylene acrylic ester glycidyl methacrylate terpolymers such as Lotader® (available from Arkema), ethylene acrylic ester maleic anhydride terpolymers such as Lotader® or Orevac® (available from Arkema).

[0206] In certain embodiments, the total thickness of the sheet including the polymer layer and the tie layer can be from about 0.002 inches to about 0.025 inches, with 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 total thickness of the sheets forming the inner liner of any configuration disclosed herein can be varied depending on the amount of radial expansion desired, as well as the strength required.

[0207] In still further embodiments, the tie layer can have a thickness of about 0.001 inches to about 0.003 inches, including exemplary values ​​of about 0.0011 inches, about 0.0012 inches, about 0.0013 inches, about 0.0014 inches, about 0.0015 inches, about 0.0016 inches, about 0.0017 inches, about 0.0018 inches, 0.0019 inches, about 0.0020 inches, about 0.0021 inches, about 0.0022 inches, about 0.0023 inches, about 0.0024 inches, about 0.0025 inches, about 0.0026 inches, about 0.0027 inches, about 0.0028 inches, and about 0.0029 inches.

[0208] In still further aspects, any of the sheath configurations disclosed herein can have at least one lubricious liner, for example as shown in Figures 25C-D.

[0209] 25C-D show an exemplary coextruded tube including a tie layer 2503 and a polymer layer 2505, as well as a lubricious liner 2507 as disclosed above. This tube can be used to form a sheet, which is then wound into a spiral configuration. Details of how to form the inner liner are described in more detail below. As can be seen herein, a lubricious liner 2507 is disposed on the tie layer 2503. It is understood that in one configuration, the tie layer and lubricious liner are disposed on the outer surface of the polymer layer (FIG. 25C) or on the inner surface of the polymer layer (FIG. 25D). In yet a further embodiment, the lubricious liner is bonded to the polymer layer of the sheet along with the tie layer.

[0210] 25E-H show various configurations of a spirally wound sheet 2502 where the sheet includes a polymer layer 2505, a tie layer 2503, and a lubricious liner 2507. FIG.

[0211] The lubricious liner can include any material capable of reducing the coefficient of friction of the sheath. In some exemplary and non-limiting embodiments, the lubricious liner can include PTFE, polyether block amide, silicone-based liner, perfluoroalkoxyalkane-based liner, e-PTFE, ethylene tetrafluoroethylene, etc. In yet further embodiments, the lubricious liner includes PTFE.

[0212] In still further aspects, the total thickness of the sheath can be any thickness, as disclosed above.

[0213] In yet other embodiments, the at least one lubricious liner has a thickness of about 0.001 inches to about 0.005 inches, such as about 0.0011 inches, about 0.0012 inches, about 0.0013 inches, about 0.0014 inches, about 0.0015 inches, about 0.0016 inches, about 0.0017 inches, about 0.0018 inches, 0.0019 inches, about 0.0020 inches, about 0.0021 inches, about 0.0022 inches, about 0.0023 inches, about 0.0024 inches, about 0.0025 inches, about 0.0026 inches, about 0.0027 inches, about 0.0028 inches, about 0.0029 inches, about 0.0030 inches, Exemplary values ​​include about 0.0031 inches, about 0.0032 inches, about 0.0033 inches, about 0.0034 inches, about 0.0035 inches, about 0.0036 inches, about 0.0037 inches, about 0.0038 inches, 0.0039 inches, about 0.0040 inches, about 0.0041 inches, about 0.0042 inches, about 0.0043 inches, about 0.0044 inches, about 0.0045 inches, about 0.0046 inches, about 0.0047 inches, about 0.0048 inches, and about 0.0049 inches.

[0214] In still further aspects, the lubricious liner may further be ribbed. It is also understood that aspects are disclosed that include additional lubricant added separately from the lubricious liner. In such aspects, the additional lubricant may be placed by any of the methods disclosed herein. It may be manually placed, pad printed, or sprayed. It is further understood that this additional lubricant, if present, may be placed in any of the predetermined patterns disclosed herein along a portion of the sheath length or along the entire length of the sheath. In yet other aspects, the additional lubricant is not present when a lubricant layer is present, as described herein.

[0215] In still further aspects, the outer layer of any one of the sheath configurations may include a styrenic elastomer, a polyurethane, a latex, a copolymer thereof, a mixture thereof, or a coextrusion thereof. In specific, non-limiting aspects, the polymer may include a polyether block ester copolymer, a polyester, a polyvinyl chloride, a thermoset silicone, a polyisoprene rubber, a polyolefin, other medical grade polymers, or a combination thereof.

[0216] In still further embodiments, the outer layer can comprise one or more layers. In some embodiments, at least one layer can include a styrenic elastomer. In other embodiments, at least one layer can include a polyurethane. While in other embodiments, at least one layer includes a mixture of a styrenic elastomer and a polyurethane.

[0217] It is understood that the hardness of each layer of the disclosed sheaths may also vary depending on the particular application and desired properties of the sheath. In some embodiments, the outer layer has a Shore A durometer of 20A to 50A, with exemplary values ​​of about 25A, about 30A, about 35A, about 40A, and about 45A.

[0218] In still further embodiments, the outer polymer layer can have a Shore hardness of less than 90 durometer, less than 80 durometer, less than 70 durometer, less than 60 durometer, less than 50 durometer, less than 40 durometer, less than 30 durometer, or less than 20 durometer. In still further exemplary embodiments, the outer polymer layer can have a Shore hardness of from about 25 durometer to about 75 durometer, with exemplary values ​​of about 30 durometer, about 35 durometer, about 40 durometer, about 45 durometer, about 50 durometer, about 55 durometer, about 60 durometer, about 65 durometer, and about 70 durometer.

[0219] The sheath as shown in any of the preceding configurations may also include an outer layer including a first polymer layer, the first polymer layer including a first compound composition including a polymer including greater than 0% and less than 100% by weight of a polyether block amide, a polyurethane, or a combination thereof, less than about 65% inorganic filler based on the total weight of the first compound composition, and up to about 20% solid lubricant filler based on the total weight of the first compound composition. However, it is understood that there are also embodiments in which the disclosed sheath can include additional components. These exemplary embodiments are disclosed herein, as detailed below.

[0220] In certain embodiments, the outer layer comprises a first polymer layer. In such exemplary embodiments, the first polymer layer can comprise a first compound composition comprising greater than 0% to less than 100% by weight of a polymer comprising a polyether block amide, a polyurethane, or any combination thereof, including exemplary values ​​of about 0.01%, about 1%, 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%, about 90%, about 95%, and about 99.9% by weight.

[0221] In still further embodiments, the first compound composition can comprise greater than about 35% to less than about 80% by weight of a polymer comprising a polyether block amide, a polyurethane, 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.

[0222] In certain embodiments, the polymer in the first compound composition comprises a polyether block amide. In such exemplary embodiments, the polyether block amide can comprise PEBAX® from Arkema. In yet further embodiments, the polymer can comprise a polyurethane, such as NEUSoft®. While in still further embodiments, the polymer can be a combination of polyether block amide, such as PEBAX® and polyurethane. It is further understood that when a mixture of polymers is present, such a mixture can comprise each component in any amount relative to another component to provide the desired polymer within the ranges disclosed above.

[0223] In still further aspects, the first compound composition can comprise less than about 65% by weight inorganic filler, including exemplary values ​​of 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 about 1% by weight inorganic filler, based on the total weight of the first compound composition.

[0224] In still further embodiments, the inorganic filler may be present in an amount of at least about 1 wt%, at least about 2 wt%, at least about 5 wt%, at least about 10 wt%, at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, at least about 35 wt%, at least about 40 wt%, at least about 45 wt%, at least about 50 wt%, or at least about 55 wt%.

[0225] In yet further aspects, the inorganic filler can include any inorganic material that can be used as a filler and is acceptable for the desired application. In certain exemplary and non-limiting aspects, the inorganic filler can include bismuth oxide chloride, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof. Again, it is understood that the inorganic filler can include a combination of various fillers. In such exemplary aspects, the amount of each filler in the combination can be within any range to provide a final combination that is within the ranges disclosed above.

[0226] In yet further embodiments, the first compound composition can include up to about 20% by weight of solid lubricant filler, including exemplary values ​​of about 0.01%, about 0.1%, about 0.5%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, and about 19.9% ​​by weight, based on the total weight of the first compound composition. In yet further embodiments, the solid lubricant filler can be present at up to about 20%, up to about 15%, or up to about 10% by weight, based on the total weight of the first compound composition.

[0227] In still further embodiments, the solid lubricant filler can include any additive known to reduce friction and behave as a lubricant. In these exemplary and non-limiting embodiments, the solid lubricant filler can include one or more of graphene, reduced graphene oxide, carbon black, boron nitride, silicone, talc, polytetrafluorethylene (PTFE), fluorinated ethylene propylene, and the like. In still further embodiments, the solid lubricant includes a PTFE filler. In yet further embodiments, the PTFE filler is a powder.

[0228] In yet a further aspect, the first compound composition can further comprise at least one tack-reducing compound.Any compound known in the art as being capable of reducing the tack of polymer compositions can be considered and used for the purposes of the present disclosure.In yet a further exemplary and non-limiting aspect, the at least one tack-reducing compound comprises ProPell™ from Foster Corporation.

[0229] In certain embodiments, the at least one stickiness reducing compound is present in an amount of 0% to about 20% by weight, including exemplary values ​​of about 0.01%, about 0.05%, about 0.1%, about 0.5%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, and about 19% by weight, based on the total weight of the first compound composition. In still further embodiments, the at least one stickiness reducing compound is present in any amount having a value between any two of the aforementioned values. For example, and without limitation, the at least one adhesion 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 compound composition.

[0230] In yet a further aspect, as disclosed herein, the polymer in the first polymer layer composition has substantially the same durometer along the entire length of the outer layer. However, it is understood that the durometer of the polymer in the first polymer layer composition of the outer layer can also vary along the length of the outer layer. For example, and without limitation, aspects are disclosed herein in which the durometer of the polymer in the first polymer layer composition at the proximal end of the outer layer is different from the durometer of the polymer in the first polymer layer composition at the distal end of the outer layer.

[0231] In still further aspects, the polymer in the first polymer layer composition has a Shore D of about 20D to about 72D, with 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 still further aspects, the polymer in the first polymer layer composition has a Shore D of about 20D to about 35D. In still further aspects, the polymer in the first polymer layer composition has a Shore D of about 30D. And in still further aspects, the polymer in the first polymer layer composition has a Shore D of about 25D.

[0232] It is understood that the outer layer disclosed herein may include embodiments in which only one polymer layer is present. Also, in other embodiments, two or more polymer layers may be present in the outer layer. In such exemplary embodiments, the outer layer may comprise a second polymer layer comprising a second compound composition comprising a second polymer comprising greater than 0% to 100% by weight of a polyether block amide, polyurethane, or a composition thereof. As with the first compound composition, the second polymer may be present in any amount within the disclosed ranges. For example, the second polymer can be present in the second compound composition from greater than 0 wt%, 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% of a polymer comprising a polyether block amide, a polyurethane, or any combination thereof. In still further embodiments, the second polymer may be present in the second compound composition from greater than about 95% to less than about 99% by weight, including exemplary values ​​of about 95.5%, about 96%, 96.5%, about 97%, about 97.5%, about 98%, and about 98.5% by weight.

[0233] In yet further embodiments, the second compound composition can further comprise up to 20% by weight of a tack-reducing additive, including exemplary values ​​of about 0.01%, about 0.05%, about 0.1%, about 0.5%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, and about 19% by weight, based on the total weight of the second compound composition. In still further embodiments, the at least one tack-reducing compound is present in any amount having a value between any two of the aforementioned values. For example, but not limited to, the at least one tack 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 compound composition. In still further embodiments, the second compound composition as disclosed herein may be substantially free of solid lubricating fillers.

[0234] It is further understood that in certain embodiments, the first polymer in the first compound composition can be the same as the second polymer in the second compound composition. Also, in other embodiments, the first polymer in the first compound composition is different from the second polymer in the second compound composition. In yet further embodiments, the second polymer layer composition includes PEBAX®, while in still further embodiments, the second polymer layer composition can include a polyurethane, such as NEUSoft® from PolyOne.

[0235] In yet further aspects, the second polymer has a Shore D of about 20 D to about 35 D. In yet further aspects, the second polymer has a Shore D of about 25 D or about 35 D.

[0236] In yet further embodiments, the second compound composition can be substantially free of inorganic fillers.While in certain embodiments, inorganic fillers can be present in the second compound composition in any amount greater than 0% 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 compound composition, such inorganic fillers can include any fillers disclosed above.

[0237] In still further aspects, as disclosed herein, the outer layer has a predetermined thickness, and 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 and / or second compound composition comprising a first and / or second polymer having a Shore D of about 30D or less.

[0238] In still further aspects, the predetermined thickness of the outer layer can vary along the length of the sheath, while in other aspects, the predetermined thickness of the outer layer is the same along the length of the sheath. In still further aspects, the predetermined thickness of the outer layer is greater at the proximal end. In still further aspects, the predetermined thickness of the outer layer is up to 0.006 inches, for example, but not limited to, about 0.001 inches to about 0.006 inches, including exemplary values ​​of about 0.0015 inches, about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, about 0.0055 inches, and about 0.006 inches.

[0239] In still further aspects, the first polymer layer and the second polymer layer can have the same thickness, while in other aspects, the first polymer layer and the second polymer layer have different thicknesses. For example, in some embodiments, the first polymer layer has a thickness of about 0.001 inches to about 0.003 inches, including exemplary values ​​of about 0.0011 inches, about 0.0012 inches, about 0.0013 inches, about 0.0014 inches, about 0.0015 inches, about 0.0016 inches, about 0.0017 inches, about 0.0018 inches, about 0.0019 inches, about 0.0020 inches, about 0.0021 inches, about 0.0022 inches, about 0.0023 inches, about 0.0024 inches, about 0.0025 inches, about 0.0026 inches, about 0.0027 inches, about 0.0028 inches, and about 0.0029 inches. In still further embodiments, the second polymer layer can have a thickness of about 0.002 inches to about 0.004 inches, and can be about 0.0011 inches, about 0.0012 inches, about 0.0013 inches, about 0.0014 inches, about 0.0015 inches, about 0.0016 inches, about 0.0017 inches, about 0.0018 inches, about 0.0019 inches, about 0.0020 inches, about 0.0021 inches, about 0.0022 inches, about 0.0 Exemplary values ​​include about 0.023 inches, about 0.0024 inches, about 0.0025 inches, about 0.0026 inches, about 0.0027 inches, about 0.0028 inches, about 0.0029 inches, 0.0030 inches, about 0.0031 inches, about 0.0032 inches, about 0.0033 inches, about 0.0034 inches, about 0.0035 inches, about 0.0036 inches, about 0.0037 inches, about 0.0038 inches, and 0.0039 inches.

[0240] In still further aspects, the predetermined thickness of the outer layer is greater at the proximal end, while in other aspects, the predetermined thickness of the outer layer is less at the distal end as compared to the predetermined thickness of the outer layer at the proximal end.

[0241] In yet further embodiments in which there are two or more layers in the outer layer, the first polymer layer can define the inner surface of the outer layer, while the second polymer layer can define the outer surface of the outer layer. However, there are also embodiments in which the first polymer layer defines the outer surface of the outer layer, while the second polymer layer defines the inner surface of the outer layer. It is also understood that other embodiments are also included in which one or more additional polymer layers are disposed between the first and second polymer layers.

[0242] In still further aspects, the outer layer is extruded as a tube that can then be slid over the inner liner of the sheath. In aspects where there is a first polymer layer and a second polymer layer, such polymer layers can be co-extruded. In still further aspects, the first polymer layer can be substantially bonded to the second polymer layer. In such exemplary aspects, the first polymer layer does not substantially delaminate from the second polymer layer. It is understood that in some aspects, the bond can be physical or chemical, or any other type known in the art.

[0243] In still further aspects, any sheath comprising an outer layer disclosed herein may exhibit an insertion force of less than about 55 N, less than about 50 N, less than about 45 N, less than about 40 N, less than about 35 N, or less than about 35 N when a medical device is pushed through the sheath.

[0244] In still further aspects, the outer layer may also exhibit a friction force in a dry state against a substrate surface comprising one or more of polytetrafluoroethylene, fluorinated ethylene propylene, or high density polyethylene having a diameter of about 0.300 inches of less than about 10 N, or less than about 9 N, or less than about 8 N, or less than about 7 N, or less than about 6 N, or even less than about 5 N.

[0245] In still further embodiments, the outer layer extruded as a tube may exhibit a hoop force at 10 mm elongation (about 85% strain) of less than about 10 N, or less than about 9 N, or less than about 8 N, or less than about 7 N, or less than about 6 N, or even less than about 5 N. In such exemplary embodiments, the extruded tube that will form the outer layer of the sheath may have a diameter of about 0.290 inches (7.4 mm) and a wall thickness as disclosed herein. In embodiments in which the outer layer has a diameter of about 0.290 inches (7.4 mm) and a total wall thickness of about 0.0045 inches with a sample length of about 0.25 inches (6.4 mm), the hoop directional force at 10 mm elongation may be less than about 8 N. It is understood that in some exemplary and non-limiting embodiments, a low force at 10 mm elongation is desired for low sheath expansion force.

[0246] In still further embodiments, the outer layer can exhibit an elongation at break ranging from about 650% to about 800%, including exemplary values ​​of about 680%, about 700%, about 710%, about 750%, and about 780%. It is understood that in some exemplary and non-limiting embodiments, a high elongation is preferred in order for the outer layer to expand to a larger diameter before breaking.

[0247] In certain aspects, the outer layer extends along a portion of the length of the sheath. In these exemplary aspects, the outer layer may be located at the proximal end of the sheath, or at the middle of the sheath, or at a distal portion of the sheath, while in other aspects, the outer layer extends along the entire length of the sheath. In these exemplary aspects, the outer layer may be located at the proximal end of the sheath and extend to the distal end of the sheath.

[0248] In still further aspects, the outer layer of any one of the sheath configurations disclosed herein may include one or more polymer layers. In some aspects, the first polymer layer may be the first polymer layer disclosed above. In other aspects, the outer layer may also include a second polymer layer, which may be any second polymer layer disclosed above. In some exemplary and non-limiting aspects, the second polymer layer may include polyurethane. In some exemplary and non-limiting aspects, the first polymer layer may include PEBAX alone or in combination with inorganic and solid lubricant fillers, as disclosed above. In other exemplary and non-limiting aspects, the second polymer layer may include polyurethane, such as Neusoft.

[0249] In certain aspects, the first polymer layer and the second polymer disclosed above may be co-extruded to form a bump tube. It is understood that bump tubes or tapered tubes are commonly used in a variety of applications.

[0250] It will be appreciated that in some aspects, bumped or tapered tubes may be particularly useful for certain catheter applications: neurovascular and microcatheters typically rely on a larger proximal diameter to increase pushability of the device, while a smaller distal end provides improved performance and deliverability.

[0251] In some aspects disclosed herein, the bump tube forming the outer layer of the sheath can have a predetermined length that is substantially similar to the length of the sheath, while in other aspects, the bump tube forming the outer layer of the sheath can have a predetermined length that is shorter than the length of the sheath.

[0252] In certain embodiments, the first polymer layer may define the inner surface of the outer layer (the bump tube). In such embodiments, the second polymer layer defines the outer surface of the outer layer.

[0253] In other embodiments, it may define the outer surface of the outer layer (bump tube). In such embodiments, the second polymer layer defines the inner surface of the outer layer.

[0254] In still further embodiments in which the outer layer has the configuration described above, the first polymer layer can have a thickness of about 0.001 inches to about 0.010 inches, with exemplary values ​​of about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, about 0.0055 inches, about 0.006 inches, 0.0065 inches, about 0.007 inches, about 0.0075 inches, about 0.008 inches, about 0.0085 inches, about 0.009 inches, and about 0.0095 inches. It is understood that the thickness of the first polymer layer in the outer layer can be uniform along the length of the sheath. Also, in other embodiments, the thickness of the first polymer layer in the outer layer can vary along the length of the sheath. In some aspects, the thickness of the first polymer layer is greater at the proximal end of the sheath compared to the thickness of the first polymer layer along other portions of the sheath, and in other aspects, the thickness of the first polymer layer can be less at the distal end of the sheath compared to the thickness of the first polymer layer at the proximal end of the sheath.

[0255] In some embodiments, the second polymer layer, when present in the outer layer, may have a thickness of about 0.001 inches to about 0.010 inches, including exemplary values ​​of about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, about 0.0055 inches, about 0.006 inches, 0.0065 inches, about 0.007 inches, about 0.0075 inches, about 0.008 inches, about 0.0085 inches, about 0.009 inches, and 0.0095 inches. It is understood that the thickness of the second polymer layer in the outer layer may be uniform along the length of the sheath. Also, in other embodiments, the thickness of the outer polymer layer in the outer layer may vary along the length of the sheath. In some aspects, the thickness of the second polymer layer is greater at the proximal end of the sheath compared to the thickness of the second polymer layer along other portions of the sheath, and in other aspects, the thickness of the second polymer layer can be less at the distal end of the sheath compared to the thickness of the second polymer layer at the proximal end of the sheath.

[0256] In still further aspects, the first polymer layer can have a Shore D of about 20D to about 72D, with 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 still further aspects, the polymer in the first polymer layer composition has a Shore D of about 20D to about 35D. In still further aspects, the polymer in the first polymer layer composition has a Shore D of about 30D. And in still further aspects, the polymer in the first polymer layer composition has a Shore D of about 25D.

[0257] In other embodiments, the second polymer layer can have a Shore A of about 30A to about 80A, with exemplary values ​​of about 40A, about 45A, about 50A, about 55A, about 60A, about 65A, about 70A, and about 75A.

[0258] In still further embodiments, the outer layer has a total predetermined thickness, and 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 total predetermined thickness comprises a first compound composition comprising a first polymer having a Shore D of about 20 D to about 35 D. In still further embodiments, the total predetermined thickness of the outer layer is at most about 0.02 inches, or at most about 0.015 inches, or at most about 0.01 inches, or at most about 0.009 inches, or at most about 0.008 inches, or at most about 0.007 inches, or at most about 0.006 inches.

[0259] In still further aspects, the total predetermined thickness of the outer layers can be uniform along the length of the sheath or can vary along the length of the sheath. In some exemplary and non-limiting aspects, the total predetermined thickness of the outer layers is greater at the proximal end of the sheath. In other aspects, the total predetermined thickness of the outer layers is less at the distal end of the sheath as compared to the total predetermined thickness of the outer layers at the proximal end of the sheath.

[0260] Also disclosed herein are sheath embodiments in which the outer layer has one or more layers that are formed separately. For example, as described above, the first and second polymer layers are formed separately instead of being coextruded. In such embodiments, the outer layer is formed by placing one of the polymer layers on top of the other.

[0261] In some exemplary and non-limiting embodiments, the second polymer layer can be disposed at least partially over the first polymer layer. Also disclosed are embodiments in which the first polymer layer is at least partially over the second polymer layer.

[0262] In certain embodiments, when two polymers are formed separately and placed on top of each other, each of the polymer layers can have a different length.

[0263] In some exemplary and non-limiting embodiments, the first polymer layer may have a length that is shorter than the length of the second polymer layer. In some embodiments, the first polymer layer may be disposed on the inner liner at the proximal end of the sheath and may have a length of about 5 cm to about 15 cm, including exemplary values ​​of about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, and about 14 cm. In still further embodiments, the second polymer layer is then disposed on the first polymer layer. In such embodiments, the second polymer layer may have any length that is compatible with the desired application. In certain embodiments, the second polymer layer may have a length that is substantially the same as the length of the sheath.

[0264] However, it is understood that the opposite configuration of the outer layer is also disclosed. In such aspects, the second polymer layer may be disposed first on the inner liner and may have a length that is shorter than the length of the sheath. Furthermore, the second polymer layer may be disposed on the second polymer layer. In such exemplary aspects, the first polymer layer may have any length. In some aspects, the length of the first polymer layer may be substantially the same as the length of the sheath.

[0265] Still further, as disclosed in these embodiments, the first polymer layer can have a uniform thickness along the length of the first polymer layer, or can vary along the length of the first polymer layer. For example, the thickness of the first polymer layer (d2, e.g., as shown in FIG. 42B, 4200) can be any thickness, as disclosed above. In some embodiments, the thickness can be any value between about 0.001 inches and about 0.006 inches, including exemplary values ​​of about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, and about 0.0055 inches.

[0266] Still further, as disclosed in these embodiments, the second polymer layer can have a uniform thickness along the length of the second polymer layer, or can vary along the length of the second polymer layer. The thickness of the second polymer layer can be any thickness, as disclosed above. In some embodiments, the thickness d1 of the second polymer can be any value between about 0.001 inches and about 0.010 inches, as shown, for example, in FIG. 42C, 4200, including exemplary values ​​of about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, about 0.0055 inches, about 0.006 inches, 0.0065 inches, about 0.007 inches, about 0.0075 inches, about 0.008 inches, about 0.0085 inches, about 0.009 inches, and about 0.0095 inches.

[0267] In still further embodiments, the overall thickness of the outer layer can be any value between about 0.001 inches and about 0.015 inches, including about 0.0015 inches, about 0.002 inches, about 0.0025 inches, about 0.003 inches, about 0.0035 inches, about 0.004 inches, about 0.0045 inches, about 0.005 inches, about 0.0055 inches, about 0.006 inches, 0.0065 inches, about 0.00 Exemplary values ​​include about 7 inches, about 0.0075 inches, about 0.008 inches, about 0.0085 inches, about 0.009 inches, 0.0095 inches, about 0.01 inches, about 0.0105 inches, about 0.011 inches, about 0.01105 inches, about 0.012 inches, about 0.01205 inches, about 0.013 inches, about 0.01305 inches, about 0.014 inches, and about 0.01405 inches.

[0268] In still further aspects, the outer layer disclosed herein can comprise at least two polymer layers. In still further aspects, the outer layer disclosed herein can comprise at least one intermediate reinforcing layer disposed between a first polymer layer and a second polymer layer. In still further aspects, the at least one intermediate reinforcing layer is a polymer layer.

[0269] In some embodiments, at least one intermediate layer can extend along the entire circumference of the outer layer. In still further embodiments, where the first polymer layer forms the inner surface of the outer layer and the second polymer layer forms the outer surface of the outer layer, the intermediate layer is disposed between the outer surface of the first polymer layer and the inner surface of the second polymer layer. In still other embodiments, where the second polymer layer forms the inner surface of the outer layer and the first polymer layer forms the outer surface of the outer layer, as disclosed above, the intermediate layer is disposed between the outer surface of the second polymer layer and the inner surface of the first polymer layer. In still further embodiments, the intermediate reinforcing layer can join the first and second polymer layers and can also assist in joining the outer layer as a whole to the inner member of the sheath.

[0270] In still further embodiments, the at least one intermediate layer has a finite width that is less than the circumference of the outer layer. In such embodiments, the at least one intermediate layer can be inserted as a strip between the first and second polymer layers. In some exemplary and non-limiting embodiments, where the outer layer has a distal outer diameter of about 0.200 inches, the strip can be 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 The strip may have a width (w, e.g., as shown in FIG. 42B, 4200) of about 0.010 inches to about 0.150 inches, with exemplary values ​​of 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. It is understood that the widths shown above are exemplary and that if the distal outer diameter of the outer layer has a size different from 0.200 inches, the strip widths may be adjusted in the same or different proportions.

[0271] In still further embodiments, the at least one intermediate layer has a finite width that is less than the circumference of the outer layer. In such embodiments, the 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, when the outer layer has a distal outer diameter of about 0.200 inches, the strip can have a width of about 5% to about 50% of the circumference of the outer layer. In still further embodiments, the total 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 outer layer. It is understood that the widths shown above are exemplary and that when the distal outer diameter of the elongate sheath has a size different from 0.200 inches, the strip widths can be adjusted in the same or different proportions.

[0272] In still further embodiments, the outer layer can comprise two or more intermediate layers. In such embodiments, the two or more intermediate layers can be disposed as individual strips circumferentially between the first and second polymer layers at a predetermined distance from each other. In embodiments where two or more intermediate layers are disposed between the first and second polymer layers of the outer layer, the total combined width of all strips is about 5% to about 50% of the circumference of the outer layer. In still further embodiments, the total 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 outer layer.

[0273] In still further aspects, the at least one intermediate layer is configured to provide axial reinforcement to the outer layer, and, consequently, to the sheath in which the outer layer may be used. In such exemplary aspects, the at least one intermediate layer may be disposed along the length of the outer layer, or along a portion of the length of the outer layer.

[0274] In some embodiments, the portion of the length of the outer layer along which the at least one intermediate layer is disposed is located at the distal and / or proximal end of the outer layer, while in other embodiments, the at least one intermediate layer may also be located anywhere along the length of the outer layer.

[0275] It will be further understood that in embodiments in which the intermediate layer is present as one or more strips circumferentially disposed along the length of the sheath, the width of the strips may be the same along the length or may vary along the length. In embodiments in which the width of the strips varies along the length of the outer layer, such strips may have any of the width values ​​disclosed above.

[0276] In yet a further embodiment, the first polymer layer used in this exemplary outer layer can be any of the first polymer layers described above. In yet a further exemplary and non-limiting embodiment, the first polymer layer forms the inner surface of the outer layer and comprises a first compound composition comprising a polymer comprising greater than 0 wt% and less than 100 wt% of a polyether block amide, a polyurethane, or a combination thereof, based on the total weight of the first compound composition, less than about 65% of an inorganic filler, based on the total weight of the first compound composition, and up to about 20% of a solid lubricant filler, based on the total weight of the first compound composition.

[0277] Any of the inorganic fillers and solid lubricant fillers disclosed above can be present in any amount disclosed.For example, the inorganic filler can include bismuth oxide chloride, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof.In yet another embodiment, the inorganic filler can be present in at least 10% by weight.In yet a further embodiment, the inorganic filler can be present in an amount of less than about 50% by weight based on the total weight of the first compound composition.

[0278] In yet a further embodiment, the solid lubricant filler can include a PTFE filler.

[0279] The first compound can also include any of the additives disclosed above. For example, the compound can include at least one tack-reducing compound in an amount of about 1% to about 20% by weight.

[0280] In yet further exemplary embodiments, the polymer present in the first compound can 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.

[0281] In still further aspects, the durometer of the polymer in the first polymer layer composition at the proximal end of the outer layer can be different from the durometer of the polymer in the first polymer layer composition at the distal end of the outer layer.

[0282] In still further aspects, the polymer in the first compound can include a polyether block amide, such as PEBAX®, while in other aspects, the polymer in the first compound can include a polyurethane. In still further aspects, the first compound can also include a polyamide.

[0283] In still further embodiments, the thickness of the first polymer layer is about 1.1 mils, about 1.2 mils, about 1.3 mils, about 1.4 mils, about 1.5 mils, about 1.6 mils, about 1.7 mils, about 1.8 mils, about 1.9 mils, about 2.0 mils, 2.1 mils, about 2.2 mils, about 2.3 mils, about 2.4 mils, about 2.5 mils, about 2.6 mils, about 2.7 mils, about 2.8 mils, about 2.9 mils, about It can be from about 1 mil to about 5 mils, including exemplary values ​​of about 3.0 mils, about 3.1 mils, about 3.2 mils, about 3.3 mils, about 3.4 mils, about 3.5 mils, about 3.6 mils, about 3.7 mils, about 3.8 mils, about 3.9 mils, about 4.1 mils, about 4.2 mils, about 4.3 mils, about 4.4 mils, about 4.5 mils, about 4.6 mils, about 4.7 mils, about 4.8 mils, and about 4.9 mils.

[0284] In still further aspects, the second polymer layer can include any of the polymers disclosed above. In some aspects, the second polymer layer can include a second compound composition comprising a second polymer comprising greater than 0% to 100% by weight of a polyether block amide, a polyurethane, or a composition thereof. In still further aspects, the second polymer layer can include a polyamide. In still some other aspects, the second compound can also include any of the fillers or additives disclosed above. Meanwhile, in some aspects, the second compound does not include a solid lubricant filler as disclosed herein. Meanwhile, in still further aspects, the second compound can include a tack reducing additive as described in the present disclosure. In some aspects, the second polymer can be a polyurethane. In still further aspects, the polyurethane is a thermoplastic polyurethane.

[0285] Meanwhile, in still further aspects, the second polymer can be a mixture including polyurethane with styrene block copolymer. In still further aspects, the mixture can further include additional polymers and copolymers. For example, an ether-based polymer can be present in the mixture. In some exemplary and non-limiting aspects, the second polymer can be selected from commercially available polymers sold under the trade name Neusoft™. In still further aspects, the second polymer can 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 still further aspects, the second polymer can have a Shore A durometer of less than 60A. In some exemplary aspects, the second polymer can be Neusoft™ 597-50A.

[0286] In still further embodiments, the thickness of the second polymer layer is about 1.1 mils, about 1.2 mils, about 1.3 mils, about 1.4 mils, about 1.5 mils, about 1.6 mils, about 1.7 mils, about 1.8 mils, about 1.9 mils, about 2.0 mils, 2.1 mils, about 2.2 mils, about 2.3 mils, about 2.4 mils, about 2.5 mils, about 2.6 mils, about 2.7 mils, about 2.8 mils, about 2.9 mils, about 3.0 mils, about 3.1 mils, about 3.2 mils, about 3.3 mils, about 3.4 mils, or about 3.5 mils. The viscosity may be from about 1 mil to about 6 mils, including exemplary values ​​of about 3.5 mils, about 3.6 mils, about 3.7 mils, about 3.8 mils, about 3.9 mils, about 4.1 mils, about 4.2 mils, about 4.3 mils, about 4.4 mils, about 4.5 mils, about 4.6 mils, about 4.7 mils, about 4.8 mils, about 4.9 mils, about 5.1 mils, about 5.2 mils, about 5.3 mils, about 5.4 mils, about 5.5 mils, about 5.6 mils, about 5.7 mils, about 5.8 mils, and about 5.9 mils. In still further embodiments, the thickness of the at least one intermediate reinforcing layer is about 1.1 mils, about 1.2 mils, about 1.3 mils, about 1.4 mils, about 1.5 mils, about 1.6 mils, about 1.7 mils, about 1.8 mils, about 1.9 mils, about 2.0 mils, 2.1 mils, about 2.2 mils, about 2.3 mils, about 2.4 mils, about 2.5 mils, about 2.6 mils, about 2.7 mils, about 2.8 mils, about 2.9 mils, about 3.0 mils, about 3.1 mils, about 3.2 mils, about 3.3 mils, about 3.4 mils, or about 3.5 mils. The viscosity may be any value from about 1 mil to about 6 mils, including exemplary values ​​of about 3.5 mils, about 3.6 mils, about 3.7 mils, about 3.8 mils, about 3.9 mils, about 4.1 mils, about 4.2 mils, about 4.3 mils, about 4.4 mils, about 4.5 mils, about 4.6 mils, about 4.7 mils, about 4.8 mils, about 4.9 mils, about 5.1 mils, about 5.2 mils, about 5.3 mils, about 5.4 mils, about 5.5 mils, about 5.6 mils, about 5.7 mils, about 5.8 mils, and about 5.9 mils.

[0287] In still further aspects, at least one intermediate layer can include any of the polymers disclosed herein. In some aspects, at least one intermediate layer can include the first compound disclosed above. In other aspects, at least one intermediate layer can include the second compound disclosed above. Meanwhile, in still further aspects, at least one intermediate layer can include the first compound. Also, in still further aspects, at least one intermediate layer can include any polymer known in the art and suitable for the desired application. In some aspects, at least one intermediate layer can include polyether block amide, polyurethane, or a combination thereof. Meanwhile, in still further aspects, at least one intermediate layer is a polyether block amide, such as PEBAX®. Meanwhile, in still further aspects, the intermediate layer is a polyurethane. In these exemplary aspects, at least one intermediate layer does not include a solid lubricant filler, such as PTFE. In still other aspects, at least one intermediate layer does not include an inorganic filler. In still further embodiments, at least one intermediate layer can comprise a polymer, including 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.

[0288] In yet further embodiments, the at least one intermediate reinforcing layer can comprise a polyolefin. In yet further embodiments, the at least one intermediate reinforcing layer can comprise polyethylene, polypropylene, graft modified polyethylene, or polypropylene. In yet further embodiments, the at least one intermediate reinforcing layer can comprise 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 polymers and substantially linear ethylene polymers, grafted polypropylene, or ethylene vinyl acetate (EVA), or any combination thereof. In such exemplary embodiments, maleic anhydride or acrylic acid can be used to graft the polymers disclosed above. In yet further embodiments, the at least one intermediate reinforcing layer can comprise maleic anhydride or acrylic acid grafted low density polyethylene. In yet further embodiments, the at least one intermediate reinforcing layer can comprise maleic anhydride or acrylic acid grafted polypropylene. In yet a further aspect, the at least one intermediate reinforcing layer can comprise maleic anhydride or acrylic acid grafted ethylene vinyl acetate. In yet a further aspect, the at least one intermediate reinforcing layer can comprise a maleic anhydride grafted polyolefin sold under the trademark OREVAC®.

[0289] In still further aspects, any of the at least one intermediate reinforcing layer disclosed above can thermally bond the outer layer to the variable inner liner of the sheath. In still further aspects, the intermediate reinforcing layer can be extruded so as to be positioned between the first and second polymer layers. In still further aspects, the at least one intermediate reinforcing layer can be fused to the first and second polymer layers by at least one of heat or compression.

[0290] In still further aspects, the outer layer disclosed herein with at least one intermediate reinforcing layer may exhibit an expansion force of less than about 50N, less than about 49N, less than about 48N, less than about 47N, less than about 46N, less than about 45N, less than about 44N, less than about 43N, less than about 42N, less than about 41N, or even less than about 40N. However, it is further understood that the expansion force depends on the size of the medical device passing through the sheath. The exemplary values ​​shown above are suitable for a medical cardiac implant of about 26 mm. It is understood that the force values ​​are not limited to the values ​​disclosed above and are adjusted depending on the device size.

[0291] In still further aspects, outer layers disclosed herein comprising at least one intermediate reinforcing layer may exhibit a burst pressure of greater than about 4.5 psi, greater than about 5 psi, greater than about 5.5 psi, greater than about 6 psi, greater than about 6.5 psi, greater than about 7 psi, greater than about 7.5 psi, greater than about 8 psi, greater than about 8.5 psi, greater than about 9 psi, greater than about 9.5 psi, greater than about 10 psi, greater than about 10.5 psi, greater than about 11 psi, greater than about 11.5 psi, greater than about 12 psi, greater than about 12.5 psi, greater than about 13 psi, greater than about 13.5 psi, greater than about 14 psi, greater than about 14.5 psi, or greater than about 15 psi.

[0292] 35-36, outer layer 140 can include one or more axial reinforcing members 145 that extend longitudinally along all or a portion of outer layer 140. Reinforcing members 145 help prevent axial packing of outer layer 140 during insertion into a patient's vasculature, while not sacrificing the low radial expansive force of outer layer 140.

[0293] 10, the sheath 100 can include a tapered segment adjacent to a wide end portion 114 at the proximal end of the sheath 100. The tapered segment and the wide end portion 114, referred to as a strain relief section, help to ease the transition between the smaller diameter portion of the sheath 100 and the housing 101. If present, the thickness and / or composition of the outer layer 140 can be tailored to improve the performance of the strain relief section and to reduce push forces as disclosed above.

[0294] For example, in certain aspects, the outer layer 140 can be joined at the proximal and / or distal ends of the inner liner. At the proximal and distal ends, the outer layer 140 can be joined to the inner liner around the entire circumference of the outer layer.

[0295] As disclosed herein, the outer layer can have the same diameter throughout the length of the sheath, or can have a diameter that varies throughout the length of the sheath. FIG. 37 is an elevational view of the outer layer 140 showing the tapered segment adjacent the wide-mouthed end portion at the proximal end of the sheath. FIG. 38 is a cross-sectional view of an exemplary elongated tube taken along section line AA in FIG. 37. FIG. 39 is a cross-sectional view of the outer layer 140 taken along section line BB in FIG. 37. As described above, the tapered portion is referred to as a strain relief section, and the tapered segment and the wide-mouthed proximal end help to ease the transition between the smaller diameter portion of the sheath 100 and the housing 101. The length of the proximal end (L1) can 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) can 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 overall length (L3) of the outer layer 140 / sheath 100 can range from 17,600 inches to 26,400 inches. In some embodiments, the overall length (L3) of the outer layer 140 / sheath 100 is about 22,000 inches.

[0296] As provided in FIG. 38, the diameter of the outer layer 140 at the proximal end is larger than the diameter of the outer layer 140 at the distal end. This allows the outer layer 140 to be slid over the inner liner 108 without having to be expanded. For example, the diameter (D1) of the outer liner 140 at the proximal end can range from 0.264 inches to 0.396 inches. In some embodiments, the diameter (D1) of the outer liner 140 at the proximal end is about 0.330 inches. The diameter (D2) of the outer layer 140 at the distal end can range from 0.176 inches to 0.264 inches. In some embodiments, the diameter (D2) of the outer layer at the distal end is about 0.220 inches.

[0297] In still further embodiments, the outer layer 140 may comprise two or more reinforcing members 145. In such embodiments, the two or more reinforcing members 145 may be disposed as individual strips within the first polymer layer, within the second polymer layer, or disposed circumferentially between the first and second layers at a predetermined distance from each other. FIG. 39 is a detailed view of the outer layer 140 taken along section line BB of FIG. 37. As provided in FIG. 39, the outer layer 140 includes three reinforcing members 145. In some embodiments, the outer layer 140 includes only one reinforcing member 145 (FIG. 40). In other embodiments, the outer layer includes up to eight reinforcing members 145. When two or more reinforcing members 145 are used, the reinforcing members are evenly spaced around the circumference of the outer layer 140. As further illustrated in FIG. 39, the reinforcing members 145 may have a rectilinear shape (e.g., rectangular) in cross section. However, any other regular or irregular shape is contemplated. For example, the reinforcing member may also be round in cross section.

[0298] In further embodiments, the reinforcing members 145 have a finite width that is less than the circumference of the outer layer 140. The total combined width (w) of the reinforcing members 145 can range from 5% to 50% of the circumference of the outer layer 140. In still further embodiments, the total 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 outer layer.

[0299] FIG 40 includes a partial view of the outer layer 140 of FIG 39. As provided in FIG 40, the circumferential width of the reinforcing member 145 can range from 0.010 inches to 0.150 inches. In some embodiments, the distal end of the outer layer 140 has a diameter of 0.200 inches and the circumferential width of the reinforcing member 145 can range from 0.010 inches to 0.150 inches. In some exemplary, non-limiting embodiments, the diameter of the outer layer at the distal end is about 0.200 inches and the reinforcing member can have a width of 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. It is understood that the widths shown above are exemplary and that if the distal outer diameter of the elongate sheath has a size different than 0.200 inches, the strip widths may be adjusted in the same or different proportions. In still yet further aspects, as described above, the width of the reinforcing member may be measured as a percentage of the circumference of the outer layer.

[0300] It will be further understood that in embodiments in which reinforcing members 145 are present as one or more strips circumferentially disposed along the length of outer layer 140, the width of reinforcing members 145 may be the same along the length or may vary along the length. In embodiments in which the width of reinforcing members 145 varies along the length of outer layer 140, such reinforcing members 145 may have any of the width values ​​disclosed above.

[0301] In still further embodiments, the at least one reinforcing member 145 is configured to provide axial reinforcement to the outer layer 140. In these exemplary embodiments, the at least one reinforcing member 145 may be disposed along the length of the outer layer 140 or along a portion of the length of the outer layer 140. In some embodiments, at least the portion of the length of the outer layer 140 on which the reinforcing member 145 is disposed is positioned at the distal and / or proximal ends of the outer layer 140. In yet other embodiments, the reinforcing member 145 may also be positioned anywhere along the length of the outer layer 140.

[0302] As mentioned above, as shown in FIG. 39, the outer layer of the sheath 140 comprises a bilayer structure including a first polymer layer 146 (positioned against the inner liner of the sheath) and a second polymer layer 147 (positioned further from the inner liner of the sheath and forming the outer layer of the outer layer of the sheath). However, it is further understood that the outer layer can have both a bilayer structure and a trilayer structure depending on the location. In some aspects, the layer formed by the second polymer can provide abrasion resistance (e.g., between the sheath and the calcific lesion) and better resistance to hydrophilic coating processes, while the layer formed by the first polymer includes a more lubricious material (e.g., to prevent the outer layer from sticking to the inner liner of the sheath during expansion) and provides better pressure resistance or ballooning resistance and hemostasis. In some embodiments, the layer formed by the first polymer 146 forms the inner surface of the outer layer 140, the layer formed by the second polymer 147 forms the outer surface of the outer layer of the sheath, and the reinforcing member 145 is disposed between the outer surface of the first polymer layer 146 and the inner surface of the second polymer layer 147.

[0303] In some embodiments, the first polymer layer 146 may be constructed from Pebax or polyurethane having a Shore 25D to 35D. In some embodiments, the first polymer layer 146 includes PTFE powder, optional inorganic fillers, and optional adhesion reducing additives to reduce friction as the sheath inner member 108 expands by sliding against the outer layer 140. In some embodiments, the second polymer layer 147 of the outer layer 140 is constructed from a polyurethane or polyurethane / styrene block copolymer (SBC) having a Shore A durometer of less than about 60, such as Neusoft 597-50A having a Shore A hardness of about 55A. In certain embodiments, the first polymer layer 146 is constructed from a polyether block amide, such as Pebax, having a Shore D durometer of less than about 35.

[0304] As provided in FIG. 39 and FIG. 40, the reinforcing member 145 is at least partially embedded in the first polymer layer 146. In some embodiments, the thickness of the reinforcing member 145 is less than the thickness of the first polymer layer 146. For example, as illustrated in FIG. 40, the reinforcing member 145 has a thickness ranging from 0.0005 inches to 0.00155 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 first polymer 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 first polymer layer 146. In further embodiments, the reinforcing member 145 has a thickness greater than the thickness of the first polymer layer 146. In some embodiments, the first polymer layer 146 and the reinforcing member 145 are coextruded. Similarly, the first polymer layer 146, the reinforcing member 145, and the second polymer layer 147 are coextruded with the reinforcing member 145 positioned between the first polymer layer 146 and the second polymer layer 147. In other embodiments, the first polymer layer 146 is provided over the reinforcing member 145, and the two components are bonded or fused together by at least one of heat or compression.

[0305] FIG. 41 shows a cross-sectional view of another exemplary outer layer in a resting (unexpanded) configuration including one reinforcing member taken along section line BB at 35.

[0306] As described above, the reinforcing member 145 is constructed from a material that is stiffer than the main body portion of the outer layer 140 (first polymer layer 146, second polymer layer 147) and also has a low coefficient of friction (e.g., high density polyethylene). In some embodiments, the reinforcing member 145 is constructed from a polymer that is compatible with the first and second polymer layers, including, for example, high durometer Pebax or polyurethane. The reinforcing member 145 can also be constructed from a material having a Shore D durometer ranging from 45D to 76D.

[0307] Additional examples of sheaths that may be used with the outer layers disclosed herein can be found in US Application No. 63 / 021,945, the contents of which are incorporated herein in their entirety.

[0308] Additional exemplary bi-layer structures are shown in Figures 42A-42C. In such configurations, for example, the reinforcing member can be part of the inner layer, where the reinforcing member has substantially the same thickness as the inner layer (shown at 4200 in Figures 42A and 42B).

[0309] In some exemplary and non-limiting embodiments, when the two polymer layers of the outer layer are formed separately, a tie layer can be disposed between the two. It is further understood that any tie layer disclosed above can be utilized.

[0310] As discussed in detail above, an important function of the sheath is that it has a clinically acceptable pushing force against all patient anatomy.

[0311] To reduce the pushing force, various types of lubrication may be used. Some of the various lubrication types and methods are disclosed above. As disclosed, any of the disclosed lubricants (lubricious materials, lubricious fillers, lubricious liners) may reduce the frictional forces between the various layers of the sheath sliding over each other, making it easier for the delivery system to open the sheath. However, lubrication between the inner liner and the outer layer may make the outer layer slide easily over the sheath shaft. When a large portion of the outer layer slides together, the outer layer may bunch up at one spot, thereby increasing the outer diameter (OD) (called bunching). This may lead to trouble inserting or retrieving the sheath, and more traumatic interactions with the vessel.

[0312] In certain aspects, to avoid this problem, the outer layer can be bonded to the inner liner of the expandable sheath to prevent migration of the outer layer along the sheath shaft.

[0313] In certain aspects, bonding of the inner liner and outer layer can occur anywhere. In yet further aspects, such bonding can occur over areas of the sheath cross section designed to cause minimal stretching of the outer layer during expansion. Bonding can also occur where no lubrication is applied.

[0314] Thus, embodiments are disclosed herein in which at least a portion of the innermost surface of the outer layer is bonded to at least a portion of the outermost surface of the inner liner. Such exemplary embodiments are also depicted in Figures 27A and 27B. It is understood that such bonding may be optionally present in any one of the sheath configurations disclosed above. Bonding may be by any method known in the art. In some embodiments, bonding is by laser welding, compression bonding, and / or selective ultrasonic welding.

[0315] In certain embodiments, the bonding of the outer layer to the inner liner may occur on a section of the sheath cross section where the outer layer is not expected to stretch or move much relative to the inner liner during expansion. In yet further exemplary and non-limiting embodiments, the portion of the inner member immediately adjacent the end of the outer layer meets this criterion. As shown in FIGS. 27A-27B, the bond 2790 is made between the inner liner 2702 and the outer layer 2708 in a portion that is not expected to stretch or move much relative to the inner liner. In such embodiments, lubrication 2707 is not applied at this location on the inner liner to ensure a good bond between the two components. At this location, the outer layer may be bonded in place along the length of the sheath shaft to prevent longitudinal movement on the inner member. In yet other embodiments, the outer layer may be bonded to the inner liner at a portion of the sheath. The bond disclosed herein does not prevent movement of the inner liner relative to the outer layer or stretching of the outer layer itself, so the force required to expand the sheath is not adversely affected by the bond.

[0316] In still further aspects, it is understood that the location of the bond may be important to minimize pushing forces. In other aspects, the bond covers a relatively small portion of the sheath circumference. In other aspects, the method of making the bond must be precisely controlled to ensure repeatability of the process. Specific methods of making the bond are described in detail below.

[0317] In still further embodiments, two or more portions of the inner liner and outer layer can be bonded together. In such exemplary embodiments, the bond can be formed in a predetermined pattern. In still further embodiments, the bond pattern can be aligned with the lubricant pattern. In such embodiments, the bond can be made in any portion of the sheath where no lubricant is present.

[0318] It is understood that when a sheath is used to deliver a prosthesis into a patient's blood vessel, hemostasis may be compromised if blood from the patient's arteriotomy penetrates between the inner liner and the outer layer, in such a scenario, the outer layer is the only sheath element that resists blood pressure and maintains hemostasis.

[0319] The outer layer is typically formed from a material that, on the one hand, allows easy expansion of the inner liner, and, on the other hand, can exert an inward force on the inner liner, causing it to contract to its original, unexpanded configuration. However, a sufficiently high blood pressure can cause the outer layer to "bulge" and, at some point, even breach and compromise hemostasis. A schematic representation of such a phenomenon is shown in FIGS. 29A-B. An exemplary sheath 2900 having an inner liner 2902 and an outer layer 2908 is connected to a hub 2911 and inserted into a patient's anatomy 2913. If hemostasis is not maintained, the outer layer can "bulge" 2915 and undesirably affect the patient.

[0320] For portions of the sheath that are below the patient's skin level, potential ballooning may be contained by the tissue surrounding the sheath and resist blood pressure, but for portions of the sheath that are outside the patient, this undesirable phenomenon may still occur. The portion of the sheath that remains outside the patient's body may vary and depend on the patient's size and anatomy, as well as the physician's preference.

[0321] Making the outer layer material stiff enough to resist blood pressure and not swell can have the undesirable trade-off of increasing the force required to expand the inner liner and therefore increase the force required to advance the delivery system through the sheath.

[0322] The aspects described herein address this issue and help prevent excessive outer layer ballooning on the portion of the sheath that remains outside the patient's body while having a minimal impact on the force to expand the sheath.

[0323] The embodiments described herein aim to reinforce the outer layer of the sheath along its proximal section without significantly affecting its ability to expand while the delivery system is being pushed through the sheath. It is understood that in some embodiments described herein, the reinforced portion of the outer layer can remain entirely outside the patient's arteriotomy. Also, in other embodiments, at least a portion of the reinforced portion can be inserted into the patient's blood vessel. Some exemplary schematics of the disclosed embodiments are shown in FIGS. 29C-D, where a reinforced layer 3025 is disposed on the outer layer 2908 to substantially prevent a "balloon" effect. As shown in FIG. 29D, the reinforced portion of the sheath can be long enough to allow at least a portion of the reinforced portion to be inserted into the patient's anatomy 2913.

[0324] In such aspects, reinforcing the outer layer with the proximal portion of the sheath may be accomplished by disposing a reinforcing jacket having a proximal end and a distal end over at least a portion of the outer layer. As disclosed herein, the reinforcing jacket may include an elastomeric material and a reinforcing element. The reinforcing jacket is then positioned over the proximal portion of the outer layer. In such aspects, the ends of the reinforcing jacket are substantially seamlessly joined to at least a portion of the outer surface of the outer layer. This smooth transition between the outer layer and the reinforcing jacket allows for the sheath to be inserted into the patient's body.

[0325] In still further aspects, the proximal end of the reinforcing jacket may be joined to the proximal end of the outer layer, although aspects in which the proximal end of the reinforcing jacket is not bonded to the proximal end of the outer layer are also disclosed.

[0326] In certain embodiments, the reinforcing jacket can have a length of about 5 to about 15 cm, with exemplary values ​​of about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, and about 14 cm.

[0327] In still further aspects, the elastomeric material present in the reinforcing jacket can be any elastomer known in the art. In some aspects, the elastomeric material includes polyether block amides, styrenic elastomers, polyurethanes, latexes, copolymers thereof, mixtures thereof, or coextrusions thereof. In still further aspects, the elastomer can include a silicone-based elastomer.

[0328] In still further aspects, the elastomeric material can have a Shore hardness of about 10A to about 80A, including exemplary values ​​of about 20A, about 25A, about 30A, about 35A, about 40A, about 45A, about 50A, about 55A, about 60A, about 65A, about 70A, and about 75A.

[0329] In still further embodiments, the reinforcement jacket comprises a reinforcing element. Some exemplary schematics of various reinforcement jackets are shown in Figures 30A-B. The reinforcement jacket 3025 is seamlessly joined at the distal end of the reinforcement jacket to the outer layer 3008, which is disposed on the inner liner 3002. The proximal end of the reinforcement jacket may or may not be bonded to the inner liner and / or hub 3011. The reinforcing filaments 3027 are disposed within the elastomer. The reinforcing element has minimal impact on the resistance of the outer layer, to expand to a certain diameter where its resistance increases dramatically.

[0330] When the delivery system is pushed through the sheath, it only needs to expand a limited amount to accommodate the OD of the crimped valve. This limited expansion does not engage the reinforcing elements, so the effect on the force to expand the sheath to this point is minimal and comes only from the low durometer elastomer. When ballooning begins, the diameter of the outer layer and reinforcing layer will only increase until the reinforcing elements come into play and prevent excessive ballooning.

[0331] In certain aspects, the reinforcing element may include a plurality of filaments arranged in a braided configuration. In such aspects, the plurality of filaments may be arranged in a plurality of circumferential rows within the reinforcing jacket, each of the plurality having a sinusoidal configuration or any irregular configuration, or any combination thereof. In certain aspects, the braid or coil may be an expandable braid or coil.

[0332] In still further aspects, the plurality of filaments can include stainless steel, nitinol, polymeric materials, or composite materials. In certain non-limiting aspects, the filaments can include nitinol and / or other shape memory alloys. In still other non-limiting aspects, the filaments can include polyester or nylon. In still some other exemplary aspects, the filaments can include Spectra fibers, polyethylene fibers, aramid fibers, or combinations thereof.

[0333] Some exemplary embodiments of braid or coil configurations are shown in Figures 4A-4D. In certain embodiments, the braid or coil can be a generally thin, hollow, substantially cylindrical tube that includes an arrangement, pattern, structure, or configuration of filaments or struts, although other geometries can be used. Suitable filaments can be round, 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 other embodiments, suitable filaments may be round and have a diameter ranging from about 0.0005 inches thick to about 0.015 inches thick, with 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 other embodiments, suitable filaments can be flat filaments having heights 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 other embodiments, flat filaments can have widths of greater 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 geometries and sizes are also suitable for certain embodiments.

[0334] In still further aspects, the braid can have a number of crosses per inch (PIC) less than 50, less than 40, less than 30, less than 20, or less than 10. In still other aspects, the braid can have a PIC number between 10 and 2, with exemplary values ​​of 9, 8, 7, 6, 5, 4, and 3. In still further aspects, the PIC can vary along the longitudinal axis of the lumen. In still other aspects, the braid pattern can vary along the longitudinal axis of the lumen. In aspects where the braid or coil comprises a filament that is Nitinol, the Nitinol has an expanded diameter d e In yet further embodiments, where the filaments comprise stainless steel or nitinol, the filaments are configured to be atraumatic at least at the distal end of the sheath. Figures 4A-4D show partial elevational views of various configurations of the braid or coil 28. It is understood that the configuration of the braid or coil 28 may vary from section to section and along the length of the sheath. It is further understood that the configurations shown in Figures 4A-4D are not necessarily drawn to scale and represent exemplary and non-limiting embodiments only. It is further understood that the braid or coil is configured to provide torqueability of the sheath during insertion of the prosthesis.

[0335] Also, in other aspects, the reinforcing element may include wires arranged in multiple circumferential rows embedded within the elastomeric material. In such aspects, the wires may have any shape configured to expand or contract. For example, the wires may have a sinusoidal or wave shape. The phase and amplitude of the wires may vary depending on the desired application. It is understood that the frequency and total number of circumferential rows present in the elastomeric material may also vary depending on the desired application. The expansion of the wires allows the outer layer of the sheath to continue expanding until the reinforcing element present in the elastomeric material is pinched. In this configuration, the reinforcing jacket stops further expansion, thus maintaining hemostasis.

[0336] In a still further aspect, a tie layer may be disposed between the reinforcement jacket and the outer layer of the sheath.

[0337] Additional configurations of the reinforcing jacket are also disclosed. In this embodiment, the outer layer does not extend to the proximal end of the sheath, and at least a portion of the inner liner at the proximal end of the sheath is substantially free of the outer layer. This proximal portion of the sheath that is not covered by the outer layer can be any length. In some embodiments, this proximal portion is about 5 to about 15 cm, with exemplary values ​​of about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, and about 14 cm.

[0338] A proximal portion of such an outer layer may be bonded to the inner liner to ensure that there is no gap between the inner liner and the outer layer when the sheath is inserted into the patient's body. This bond may also prevent the outer layer from slipping off when the sheath is inserted into the patient's body. In such an embodiment, a reinforcing jacket having a proximal end and a distal end is then positioned over at least a portion of the outer surface of the inner liner at the proximal end of the sheath that is substantially free of the outer layer. In such a configuration, it is understood that the proximal end of the reinforcing jacket abuts the proximal end of the sheath and is at least partially joined to at least a portion of the proximal end of the outer surface of the inner liner.

[0339] Again, the reinforcing jacket can have a length substantially similar to the length of the proximal portion of the sheath without the outer layer. In some exemplary and non-limiting embodiments, the length of the reinforcing jacket can be from about 5 to about 15 cm, with exemplary values ​​of about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, and about 14 cm.

[0340] In yet a further aspect, the distal end of the reinforced jacket abuts or at least partially overlaps the proximal portion of the outer layer. It is further understood that the distal end of the reinforced jacket is seamlessly joined to at least a portion of the proximal portion of the outer surface of the outer layer. It is understood that the reinforced jacket as described in this aspect can include all of the components of the reinforced jacket disclosed above.

[0341] In yet a further aspect, a sheath having any one of the configurations disclosed above and including a ballooning guard is also disclosed. Similar to the reinforcing jacket disclosed above, the balloon guard is configured to accommodate different insertion depths of the sheath and prevent excessive outer layer ballooning on the portion of the sheath that remains outside the patient's body while not affecting the force to expand the sheath. The ballooning guard is configured to remain outside the patient's body and not be inserted into the patient's anatomy.

[0342] In aspects disclosed herein, a ballooning guard has a proximal end and a distal end and is disposed over at least a portion of the outer layer, the ballooning guard configured to remain outside the subject's blood vessel and substantially maintain hemostasis.

[0343] As described herein, the ballooning guard may be collapsible. In other aspects, the ballooning guard may be configured to adjust its length based on the insertion depth of the sheath.

[0344] In some embodiments, the inner diameter of the balloon guard may be large enough so as not to affect the force to expand the sheath or the force to advance the delivery system through the sheath, or may have minimal resistance to expansion up to a certain diameter. Once the ballooning guard reaches a certain diameter, the force to expand the ballooning guard increases significantly so that it can resist blood pressure and stop ballooning. It is understood that the ballooning guard may not prevent ballooning from starting, but may contain it so that the outer layer does not overexpand, rupture, and compromise hemostasis. An exemplary schematic diagram of a portion of the balloon guard is shown in FIGS. 29E-29F. The ballooning guard 3125 is positioned on the outer layer 2908 so that blood 2915 may be able to enter the portion between the outer layer 2908 and the inner layer 2902, but does not cause the sheath to rupture and helps maintain hemostasis.

[0345] In still further aspects, the proximal end of the ballooning guard is connected to a proximal-most portion of the outer layer and / or the hub of the sheath, while the distal end of the ballooning guard radially surrounds at least a portion of the outer layer, and the distal end is not bonded to the outer layer. It is understood that, as described herein, the ballooning guard seals against the subject's skin and is not inserted into the subject's anatomy 2913.

[0346] In still further aspects, the ballooning guard may comprise a braided or coiled sleeve including a plurality of filaments. Any of the plurality of filaments disclosed above may be utilized. In some aspects where a braided or coiled sleeve is present, at least a portion of the plurality of filaments at the distal end of the ballooning guard are bonded together to shorten the braided or coiled sleeve and allow it to seal against the outer layer and against the patient's skin.

[0347] In still further aspects, the braided or coiled sleeve can also include a polymer. Any of the elastomeric polymers disclosed above can be used. In certain aspects, the braid or coil can be embedded with a polymer. It is understood that the braid or coil material can be any material known in the art. In certain aspects, the braid or coil material can include a metal or metal alloy. In certain aspects, any metal or metal alloy known in the art that is used in medical devices can be utilized to make the braid or coil. In some aspects, the braid or coil can be made of a shape memory material. In still further aspects, the braid or coil can be any braid or coil disclosed herein.

[0348] In still other aspects, the braided material may include a polymer. It is understood that any polymer known in the art may be used to form the braid. In these exemplary and non-limiting aspects, the polymer may include any known polyolefin, any known polyamide, or any known polyester. In still further aspects, the braided material may include a woven fabric. In still further aspects, the braided sleeve may include a woven fabric. In still further aspects, the ballooning guard may include an e-PTFE tube, the ballooning guard may include an e-PTFE tube, a corrugated tube, or any polymer tube having a shape configured to be compressed. In certain aspects, the ballooning guard may include an e-PTFE tube. In these exemplary and non-limiting aspects, the e-PTFE tube may be compressed without losing its shape. Meanwhile, in still further aspects, the ballooning guard may include a corrugated tube. The corrugated tube allows the guard to be compressed and its length adjusted.

[0349] In these exemplary, non-limiting aspects, the ballooning guard may be made of any polymeric material that can have a shape that allows the material to be compressed. For example, the tube may be formed from any polymer known in the art. The walls of the tube may be cut with a pattern that allows it to be compressed without losing its initial shape.

[0350] In addition, some embodiments of any of the sheath configurations disclosed herein can include an external hydrophilic coating on the outer surface of the outer layer. Such a hydrophilic coating can facilitate insertion of any of the sheaths disclosed herein into a patient's blood vessel. Examples of suitable hydrophilic coatings include Harmony™ Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, Minnesota. DSM Medical Coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride), are also suitable for use with the sheaths.

[0351] Also, as shown in FIG. 11, a soft tip 102 may be utilized in any of the sheath configurations disclosed herein. In certain aspects, the tip may comprise 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 vasculature. For example, in some aspects, the soft tip portion 102 may be slightly tapered to facilitate passage through the blood vessels. The soft tip portion 102 may be secured to the distal end 104 of the sheath 100, such as by thermally bonding the soft tip portion 102 to the inner and outer layers of the sheath 100. Such a soft tip portion 102 may be provided with a lower hardness than other portions of the sheath 100. In some aspects, the soft tip 102 may have a Shore hardness of about 25A to about 40A, including exemplary values ​​of about 28A, about 30A, about 32A, about 35A, and about 38A. It is further understood that the Shore hardness can have any value between any two of the aforementioned values. In yet other aspects, the soft tip 102 can have a Shore hardness of about 25D to about 40D, including exemplary values ​​of about 28D, about 30D, about 32D, about 35D, and about 38D. The tip portion 102 is configured to be radially expandable to allow a prosthesis to pass through the distal opening of the sheath 100.

[0352] 11, the sheath 100 may optionally include at least one radiopaque filler or marker, such as a discontinuous or C-shaped band 112 positioned near the distal end 104 of the sheath 100. The marker 112 may be associated with the inner liner and / or the outer layers 108, 110 of the sheath 100. Such radiopaque tip markers may include materials suitable for radiopaque fillers, such as platinum, iridium, platinum / iridium alloys, stainless steel, other biocompatible metals, or combinations thereof. 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 layer of elastomeric polymer used to form the outer layer and may comprise from about 5% to about 45% by weight of the outer layer, with exemplary values ​​of about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, and about 40% by weight of the outer polymeric tubular layer. More or less radiopaque material may be used in some embodiments, depending on the particular application.

[0353] The sheaths disclosed herein can be configured to locally expand at specific locations corresponding to the location of a medical device along the length of the lumen, and then locally contract as the medical device passes that specific location. Thus, as a medical device is introduced through the sheath, it progresses longitudinally along the length of the sheath, and ridges may be visible that represent successive local expansions and contractions as the device progresses down the length of the sheath. In some aspects, each segment of the sheath expands or contracts relative to the original resting diameter d of the lumen. r . may locally shrink after removal of any radially outward (insertion) force so as to regain

[0354] In some embodiments, each segment of the sheath has an original resting diameter d r After any outward radial force is removed, the localized contraction can occur at least partially back to normal.

[0355] 44-66 disclose an embodiment of an expandable sheath 4400 and a method of making the same, including a proximal section 4402 and a distal tip section 4404 that may be permanently split to facilitate retrieval of a medical device. The sheath 4400 defines an inner lumen 4406 extending therethrough for passage of a medical device, such as those described above. The proximal section 4402 may include an expandable inner liner layer 4408, for example of a scroll or spiral type, having slits along it that allow its edges to overlap. The inner liner layer 4408 expands and collapses locally under a bias from a surrounding elastomeric jacket or outer layer 4410 as a medical device passes therethrough. The tip section 4404 defines a slit 4412 extending from a distal end 4416 of the proximal section 4402 and, in some cases, extending the majority of the length of the tip section, except for the distal end 4422 of the tip section. The slits 4412 also extend through most or all of the layers of the tip section 4404. In this manner, the portion of the lumen 4402 defined through the tip section 4404 can be expanded by the passage of a medical device therethrough.

[0356] Advantageously, the slits 4412 in the tip section 4404 present a low pushing force of less than about 25 Newtons (5.6 lbf), or in another embodiment less than about 15 Newtons (3.4 lbf) to open and remain open to facilitate partial or complete withdrawal of the medical device, if desired. The elastomeric outer layer 4410 extends over all or a portion of the tip section and contributes to a smooth surface to maintain the hemostatic and atraumatic nature of the tip section 4404. The expandable sheath 4400 may also include a radiopaque marker 4428 embedded in the tip section 4404 to enhance positioning of the expandable sheath, as shown in FIG.

[0357] 44-46, for example, the proximal section 4402 includes an elongate body 4418 extending between a proximal end 4414 and a distal end 4416. The elongate body 4418 defines a proximal portion of a lumen 4406 extending through the expandable sheath 4400. The tip section 4404 extends distally from the distal end 4416 of the proximal section 4402. The tip section 4404 includes a proximal end 4420, a distal end 4422, and a generally tapered tip body 4424 extending between the proximal end 4420 and the distal end 4422. The tip body 4424 defines a distal portion of a lumen 4406 extending through the expandable sheath 4400.

[0358] The tip section 4404 includes at least an inner liner layer 4408 that defines a slit 4412, and some relatively soft structures that extend and / or cover the inner liner layer to make the tip section atraumatic, such as an outer (jacket) layer 4410 and / or an intermediate layer 4426. In general, in some aspects, the outer layer 4410 prevents blood loss through the inner liner layer 4408 and extends over the proximal section 4402 to bias the scrolling inner liner layer 4408 into a compressed configuration, as better described herein above. In other aspects, the intermediate layer 4426 can be used to bond the inner liner layer 4408 to the outer layer 4410. (The intermediate layer 4426 may be the only thing holding the tip section 4404 together.) The intermediate layer 4426 may also mediate blood loss through the inner liner layer 4408. The intermediate layer 4426 may include its own sublayers, such as a bi-layer or tri-layer including a tie layer. Unlike scored layers, most or all of the layers in the tip section 4404 can be slit all the way through (and lightly sealed with heat reflow) for reduced pushing forces and a cleaner, more clearly defined expansion or division state, as shown in Figures 47-48.

[0359] The atraumatic tip section 4404 may be used in any catheter in which a lubricious liner, such as an HDPE (high density polyethylene) inner liner layer 4408, and an elastomeric outer jacket, for example a jacket made of a copolyamide, such as a polyether block amide (Pebax) outer layer 4410, would benefit from thermal bonding with good adhesion by the middle layer 4426. In some instances, the middle layer extends most distally as a single layer and is therefore the atraumatic portion of the tip.

[0360] The inner liner layer 4408 may be an extension of the same layer of the proximal section 4402 that performs a "scroll" function in that it has free edges defined by spirally elongated slits that expand and contract during passage of a medical device. The inner liner layer 4408 may have a generally stiffer composition than the other layers and may be comprised of, for example, polyethylene, such as high density polyethylene (HDPE) or low density polyethylene (LDPE), as well as other relatively stiff and / or lubricious polymers as described herein.

[0361] The inner liner layer 4408 of the tip section 4404 may be manufactured by modifying the distal end of the scrolled inner liner layer of the proximal section 4402. For example, as shown in FIG. 49, the manufacturer cuts the inner liner layer 4408 with two separate cuts. A first cut 4444 extends proximally from the distal edge 4432 of the inner liner layer 4408. A second cut 4434 extends perpendicularly from the proximal end of the first cut 4444 to one of a pair of side edges 4436 of the inner liner layer 4408. These two cuts form a flap 4438 that is then rewound into a scroll configuration as shown in FIGS. 50-52. The cuts 4444, 4434 are positioned to define a portion of a slit 12 through the inner liner layer 4408. In particular, the first cut 4444 is positioned to align with the opposite lateral edge 4436 of the flap 4438 on the radially inner portion of the scroll arrangement. Thus, even in the folded state, the inner liner layer 4408 does not prevent the slit 12 from extending into the bore 4406, as shown in FIGS.

[0362] The flap 4438 may have different sizes and shapes depending on the size and shape of the expandable sheath 4400, which in turn relates to the size, shape, and nature of the medical device that will be passed therethrough. However, for stent mounted heart valves and similar devices, the first cut 4444 may extend approximately 0.157 inches (4 mm) proximally and be positioned approximately 0.5 inches (12.7 mm) inward from the lateral edge 36. The second cut 4434 may extend 0.485 inches (12.3 mm) therefrom toward the lateral edge, connecting the flap to the remainder of the inner liner layer 4408 without cutting approximately 0.015 inches (0.38 mm). The flap therefore has a rectangular dimension of approximately 4 mm to 12 mm. The width of the inner liner layer 4408 between the lateral edges 4436 is about 1.068 inches (27.1 mm), so the flap is about 40%-50% of the width of the inner liner layer. The first cut 4444 generally extends about 4 mm-6 mm, or about 2 / 3 of the final length of the tip section 4404 when fully formed.

[0363] In some instances, additional or excess portions of the inner liner layer 4410 may be trimmed away as part of forming the tip section 4404. For example, as shown in FIG. 53, an additional small (2 mm to 3 mm or about 2.5 mm) rectangular piece may be removed from the distal edge 4432 to facilitate conical or tapered shaping. As described above for other embodiments, the inner liner layer 4410, including within the proximal section 4402, may include a lubricant to facilitate relative movement of the layers during expansion and contraction. However, generally the tip section 4404 does not include a lubricant as it is reflowed to form a unitary structure.

[0364] As shown in FIGS. 54-57, the configuration of the inner liner layer 4408 of FIGS. 50-52 can be mounted on a mandrel or heated die, reflowed (by application of heat) into a tapering conical shape (as shown in FIG. 67), and then trimmed to present a relatively flat distal end. In this intermediate configuration shown in FIG. 54, the tip section 4404 extends approximately 4 mm beyond the distal end 4416 of the proximal section 4402. Also, the slit 4412 extends the entire length of the tapered conical shape. It should also be noted that the proximal section 4402 still maintains a scroll configuration with an elongated edge 4440 to freely expand and contract, as described above. The two slits 4412 and 4440 are circumferentially offset from each other by approximately 44 degrees to 120 degrees, or in some embodiments 70 degrees to 120 degrees. The larger range reflects, for example, an embodiment of a sheath having a larger overlap of the rolled inner liner. The greater overlap facilitates the passage of larger medical devices, such as larger heart valves. However, as shown in FIG. 56, where the inner liner layer 4408 overlaps at the distal tip section 4404, the scrolled inner liner layer has been reflowed to form a unitary wall structure. In particular, the wall structure is thicker where the reflowed inner liner layer 4408 had an overlapping configuration in FIGS. 50-52, and is thinner at the end of the flap 4438, where there was only a single layer thickness. The wall thickness at the distal end of the inner liner layer 4408 is reduced at its thinnest point by heating to less than 0.005 inches (0.13 mm) for a circumferential length of approximately 0.080 inches (2 mm).

[0365] 56-57, the slits 4412 have narrowed somewhat due to the reflow, with adjacent overlapping layers of the inner liner layer 4408 reflowing together to form a single wall thickness. However, the overlapping scroll configuration in the proximal section 4402 remains visible because the inner liner layer 4408 has not been reflowed proximal to the tip section 4404. In this manner, the ability of the inner liner layer 4408 to expand and contract within the proximal section 4402 of the expandable sheath 4400 is maintained.

[0366] As shown in FIGS. 58-62 and 67, in one embodiment, the next step in fabricating the distal section 4404 is to apply an intermediate layer 4426 to the shaped and trimmed inner liner layer 4408 of FIGS. 54-57. The intermediate layer 4426 is formed of a relatively soft thermoplastic that facilitates connection of the inner liner layer 4408 and the outer layer 4410 and is atraumatic. (In other embodiments, the intermediate layer 4426 is not required and the layers 4408, 4410 may be bonded to one another via reflow, adhesives, mechanical fasteners, etc.) The intermediate layer 4426 also reflows at a lower temperature and provides a larger bond area for the elastomeric outer layer 4410, improving bond strength. Another advantage is that the intermediate layer 4426 can provide a lubricious inner diameter to the distal section 4404, making deployment and retrieval of the medical device easier. The intermediate layer 4426 may also provide some structural rigidity to the distal end 4422 to avoid deformations such as ovalization or "fish mouthing" at the distal end.

[0367] In one aspect, the intermediate layer 4426 extends distally about 0.040 inches (or 2 mm-3 mm) beyond the inner liner layer 4408 and the outer layer 4410. In other aspects, the intermediate layer 4426 extends distally of the layers 4408, 4410 up to about 0.080 inches. The intermediate layer 4426 may be less stiff than the inner liner layer 4408 such that the intermediate layer 4426 is more easily bent by an axial force than the inner liner layer 4408.

[0368] The middle layer 4426 can be a cylindrical single layer (such as a tie layer of about 0.012 inches (0.3 mm) and an inside diameter of about 0.199 inches (5 mm)) as shown in FIG. 68. The middle layer 4426 can have multiple sublayers (such as a bilayer or trilayer) as shown in FIG. 69. For sublayers, the tube formed in the middle layer 4426 can be coextruded. Materials for the middle layer 4426 and its (optional) sublayers include thin polymer tubes or films of thermally bondable tie layers such as Orevac 18440M (maleic anhydride modified LLDPE), Orevac 9318, or Orevac 9444 (maleic anhydride modified EVA). These can be the middle sublayer in a trilayer or the outer layer in a bilayer configuration.

[0369] 58-59, the intermediate layer 4426 is placed over the distal end of the cone-shaped inner liner layer 4408. The intermediate layer 4426 is then heated and flows downward to cover the shaped inner liner layer 4408 and form the structure shown in FIGS. 60-62 and 67. Also, or alternatively, the intermediate layer 4426 may be heat shrunk onto the inner liner layer 4408. Advantageously, the reflow of the intermediate layer 4426 does not require the use of a mandrel, but flows over the already formed surface of the inner liner layer 4408.

[0370] 67, the middle layer 4426 is not completely fused under and over the inner liner layer 4408. Instead, it extends beyond the inner liner layer 4408. For example, a thermally bondable tip tube is cut to a length of about 0.250 inches (6.35 mm) and about 0.160 inches (4 mm) of the thermally bondable tip tube overlaps a 0.160 inch (4 mm) length of the thin HDPE inner liner layer 4408, leaving a few millimeters of the middle layer 4426 extending beyond the inner liner layer 4408. This extension can then be trimmed to a tip 1 mm to 2 mm beyond the inner liner layer 4408. Also, the now extended length of tip section 4404 may again be cut or scored to supplement and extend slits 4412 through intermediate layer 4408 to within about 0.040 inches (1 mm) or 0.080 inches (2 mm) (if desired) of the distal end 4402 of tip section 4404. (Notably, this additional 1 mm to 2 mm remains uncovered by outer layer 4410 when such an outer layer is employed.)

[0371] In other embodiments, the middle layer 4426 may include two sublayers. For example, a thermally bondable tie sublayer may be formed by co-extrusion with an HDPE or LDPE inner sublayer. In one embodiment, the inner sublayer may have an inner diameter of about 0.199 inches and a thickness of 0.010+ / -0.001 inches and may be made of LDPE or HDPE. The outer sublayer is 0.002+ / -0.0005 inches and is made of a tie layer material.

[0372] In another embodiment, the middle layer 4426 can include two sublayers, such as an Orevac 18440M outer sublayer bonded to the elastomeric outer layer 4410, and an LDPE inner sublayer bonded to the inner liner layer 4408. The Orevac layer can have a thickness of about 0.002 inches, while the LDPE layer can have a greater thickness, such as 0.010 inches. Bonding the middle layers can be, for example, at 450 degrees Fahrenheit for about 1 minute using FEP heat shrink tubing.

[0373] In yet another embodiment, the outer sub-layer may include Pebax 45D (Shore D) and an Orevac inner sub-layer. The Orevac inner sub-layer may have an inner diameter of about 0.200 inches and a thickness of 0.006 inches. The Pebax 45D outer sub-layer may also have a wall thickness of about 0.006 inches. The outer sub-layer may be thermally bonded to an outer elastomeric layer 4410, such as an outer layer of Pebax 25D. The inner sub-layer may be thermally bonded to an inner liner layer 4408, such as an inner layer of HDPE.

[0374] As shown in FIG. 69, in another embodiment, the middle layer 4426 may include three sublayers: an outer sublayer 4442, a middle sublayer 4444, and an inner sublayer 4446. The inner sublayer may have a larger diameter than the middle sublayer 4444 and the outer sublayer 4442. For example, the inner sublayer 4446 may have a thickness of about 0.006-0.008 inches, the middle sublayer 4444 may have a thickness of about 0.002-0.003 inches, and the outer sublayer 4442 may have a thickness of about 0.002-0.003 inches. The inner sublayer 4446 may be comprised of a lubricious or relatively hard polymer such as HDPE or LDPE. The middle sublayer 4444 may be comprised of a tie layer material. The outer sublayer 4442 may be comprised of about Pebax 25D-45D.

[0375] In yet another embodiment, the inner sub-layer 4446 can have a thickness of about 0.005 inches with an inside diameter of 0.200 inches, the middle sub-layer 4444 can have a thickness of about 0.002 inches, and the outer sub-layer 4442 can have a thickness of about 0.005 inches. The inner sub-layer 4446 can include, for example, LDPE. The middle sub-layer 4444 can include Orevac and the outer sub-layer 442 can include Pebax 45D. Although the various layers disclosed herein for the middle layer 4426 can be mixed to form different combinations of thicknesses and materials, the LDPE of the inner sub-layer 4446 bonded well to the HDPE inner liner layer 4408 and the Pebax 45D outer sub-layer 4442 bonded well to the Pebax 25D outer layer 4410. Additionally, with the LDPE inner sub-layer 4446, the tip section 4404 was easily removed from the stainless steel forming mandrel.

[0376] In yet another embodiment, the middle layer 4408 includes an LDPE inner sub-layer 4446 having an inner diameter of 0.200 inches and a wall thickness of 0.006 inches, an Orevac middle sub-layer 4444 having a wall thickness of 0.003 inches, and a Pebax 25D outer sub-layer 4442 having a wall thickness of 0.003 inches. Notably, in this embodiment, the inner sub-layer was twice as thick as the other sub-layers.

[0377] In another embodiment, the middle layer 4426 may be formed from a multi-layer coextrusion of an HDPE or LDPE inner sub-layer 4446 , an intermediate thermally bondable bonding sub-layer 4444 , and a Pebax 25D or 35D outer sub-layer 4442 .

[0378] The tie sublayer between the Pebax and LDPE sublayers may be Orevac. Other tie layers may also be used, alone and in combination, such as functionalized olefins, e.g., maleic anhydride grafted ethylene vinyl acetate, acrylic acid modified polyolefins, and other polar functionalities are possible.

[0379] As an additional embodiment, the distal section 4404 of the expandable sheath 4400 can also include a radiopaque marker 4428. As shown in Fig. 66, the distal section 4404 carries a marker 4428 very close to the tip, for example, within a 6 mm length of the marker in an embodiment for delivering a stent mounted heart valve. Having the marker on the distal section 4404 facilitates more precise positioning of the medical device.

[0380] 63-65 diagrammatically illustrate an example of incorporating a radiopaque marker 4428 into the tip section 4404. In particular, the marker may be incorporated into the inner liner layer 4410 under the flap 4438. As shown in FIG. 63, when the inner layer is cut into the shape of FIG. 48, the marker may be placed before the flap 4438 is folded back onto the inner turn of the inner liner layer 4410. Then, as shown in FIGS. 54-57, for example, a reflow process and / or a heat shrink process (with the middle layer 4426) can encapsulate the radiopaque marker 4428 within the inner liner layer. This also contributes to the thick wall portion of the inner liner layer 4408 shown in FIG. 56. Advantageously, an additional step of heat shrinking the middle layer 4426 and the outer layer 4410 can additionally secure the radiopaque marker 4428. Figures 64-65 show, in another embodiment, the formation of the distal end of the tip section 4408 by heat shrinking and trimming the middle layer 4426 to form another 1-2 mm tip and applying the outer jacket layer 4410. The radiopaque marker is depicted in Figures 63-64 as not yet folded into the inner liner layer 4408 to illustrate its relative positioning during the assembly process.

[0381] In another embodiment, radiopaque markers may be bonded between the intermediate layer 4426 and the inner liner layer 4408, or between the outer layer 4410 and the intermediate layer 4426. In either case, having radiopaque markers in the tip section 4404 facilitates positioning of the expandable sheath 4400 by allowing for more precise visualization.

[0382] Generally, the radiopaque marker 4428 has a rectangular shape and is bent into a C-shape when folded into the distal section 4404. In one embodiment, as shown in FIG. 63, the radiopaque marker has an axial length of about 2.5 mm and is axially centered under the flap 4438, leaving, for example, 0.75 mm on either side for a 4 mm length, or 1.25 mm on either side for a 5 mm length, of the inner liner layer 4408 in the distal section 4404. As shown in FIG. 64, the middle layer 4426 overlaps the trimmed and shaped inner liner layer 4408 by about 1-2 mm and extends distally by about 2-3 mm. As shown in FIG. 65, the outer layer 4410 is applied, covering about 1 mm of the middle layer 4426, and the distal portion of the middle layer is trimmed to about 1-2 mm.

[0383] As shown in FIGS. 44-46, in one embodiment, the outer elastomeric layer 4410 extends over the inner liner layer 4408 and the middle layer 4426 of both the proximal section 4402 and the distal section 4404 of the expandable sheath 4400. For example, the outer layer 4410 slides over the entire length of the rolled inner liner layer 4408 and the tip section, leaving about 0.040 inches to 0.080 inches (1 to 2 mm) of uncovered tip at the distal end of the sheath 4400, as shown in FIG. 65. Typically, the thickness of the outer layer 4410 is about 0.005 inches. The outer layer may also have a taper to make it conform to the shape of the proximal section 4402 and the tip section 4404. The taper may be formed, for example, by heat shrinking using FEP HS tubing over a tapered mandrel.

[0384] The outer elastomeric layer 4410 can be a single layer, such as a polyurethane layer, or can include multiple sublayers. For example, the elastomeric layer can include two sublayers, such as an inner layer of low durometer PEBA, such as Pebax from Arkema, having a Shore D durometer of about 25 to less than 35. In another embodiment, the outer layer 4410 can have a Shore D durometer of 35 to 65. And the outer layer can include a low durometer polyurethane, having a Shore A durometer of about 65 to less than 75. One example is Neusoft 597-50 from NEU Specialty Engineered Materials.

[0385] In another embodiment, the outer elastomeric layer 4410 can be Neusoft 55A slid over the entire length of the rolled inner liner layer 4408, leaving the distal tip of the middle layer 4426 exposed. The layers are then heat shrunk for bonding. In one embodiment, the outer layer 4410 can be bonded directly to the inner liner layer 4408, such as when the outer layer is made of Neusoft and the inner liner layer is made of HDPE. Alternatively, the outer layer 4410 can be pulled over the middle layer 4426 at the tip section 4404, and a FEP shrink tube can be slid over the outer layer to thermally bond the outer layer to the middle layer.

[0386] In another embodiment, the elastomeric layer 4410 may be made of Pebax 25D and slid over the middle layer 4426 to facilitate thermal bonding of the layers in the tip section. As mentioned above, an optional lubricant such as Nusil may be applied to the outer surface of the inner liner layer 4408 to facilitate expansion and contraction of the inner liner layer 4408. However, the tip section 4404 generally does not have a lubricant for thermal bonding of the layers.

[0387] In another embodiment, the elastomeric layer 4410 can include a radiopaque filler, such as barium sulfate, for one or more sub-layers.

[0388] The slit 4412 has a length of about 3.8 mm to 4 mm, stopping 1 to 3 mm, and in one embodiment 2 mm, from the distal end of the tip section 4404, as described above for the expandable sheath 4403 for cardiovascular applications such as delivery of a stent-mounted heart valve. Thus, the slit 4412 is about 60% to 80% of the length of the tip section 4404. (And the length without the slit is 20% to 40% of the length of the tip section 4404.) As shown in FIGS. 45-46 and 65-66, for example, the slit is straight and may have gaps or be partially sealed from above by reflowing in various construction steps, depending on how the manufacturer wants to adjust the pressing force required to tear open the tip section 4404. In another embodiment, the outer layer 4410 and the middle layer 4426 may be split together in a single step, such as at the end of the manufacturing process.

[0389] While the illustrated embodiment has only a single linear slit 4412, the shape and number of slits can vary depending on how much pushing force is desired. In general, more slits reduces the pushing force. The slit may also have a shape that is wider at some points and narrower at other points, for example, if the pushing force needs to be less at the proximal end 4420, the slit may be wider or may branch into two slits. Or two shorter slits may be used. The pushing force may also be higher by reducing the width or length of the slit, such as by tapering or reflowing the distal end of the slit 4412. The slit also need not be straight, but may be spiral, bifurcated, include a series of enlarged gaps, etc. Overall, however, the goal is to reduce the force with which the medical device passes through the end of the expandable sheath 4400 and / or to facilitate retrieval by tearing open the tip section 4404.

[0390] The tip section 4401 is permanently changed during expansion by the stretching of the slit 4412 by tearing open the distal end 4422 through the middle layer 4426. For example, the tip section 4404 can go from a tapered shape having a smaller first diameter to a more expanded diameter after passage of the medical device. The first inner diameter can be, for example, about 4.7 mm or 0.184 inches. The expanded second inner diameter can be, for example, about 5.5 mm or 0.216 inches to about 9.0 mm or 0.354 inches, depending on the crimped valve outer diameter and the deployed valve outer diameter mounted on the valve delivery system, if the medical device is a heart valve.

[0391] As shown in FIG. 47, the slit 4412 may have a U-shape with a rounded portion on the proximal end followed by arms extending distally that separate during expansion of the tip section 4404. In particular, the U-shape has a relatively smooth and clean perimeter to it, facilitating deployment and retrieval of the medical device. FIG. 48 shows how removal of the expansion force of the medical device allows the slit 4412 to retract somewhat due to the elasticity of the layers of the tip section 4404. However, the tip section remains substantially more receptive to retrieval due to tearing and also some residual flaring open of the distal end 4422. FIG. 48 also shows how the layers may retract by different amounts, such as in one embodiment, the inner liner layer 4408 retracting more than the outer layer 4410, or vice versa.

[0392] The method of delivering a medical device includes positioning at least the distal end of the expandable sheath 4400 within a patient's blood vessel. As described above, a radiopaque marker 4428 is adjacent the distal end 4422 of the tip section 4404. The marker allows a medical technician to closely estimate the location of the distal end 4422 by viewing the location of the radiopaque marker 4428. The radiopaque marker is viewed by the medical technician via a device such as an x-ray machine. The radiopaque marker is advanced axially and aligned with a desired location within the blood vessel, such as a calcified aortic valve. The medical device is advanced distally through the sheath 4400, expanding the lumen 4406 to accommodate the size of the medical device.

[0393] As the medical device passes through the tip section 4404, the tip is radially expanded, for example, by enlarging the slit 4412 and tearing the distal-most end of the tip section, as shown in FIG. 47. As the medical device passes through the distal end 4416 of the tip section 4404 and the slit 4412 extends axially through the distal end 4422 of the tip section 4404, the diameter of the distal end of the sheath 4400 partially contracts to a diameter smaller than the expanded configuration but larger than the unexpanded configuration, as shown in FIG. 48. If desired, a medical device, such as a prosthetic heart valve, can be partially or completely withdrawn through the still somewhat expanded (and generally looser or more compliant) tip section 4404. The medical device can also be redeployed anew by expanding the tip section 4404 to its maximum diameter.

[0394] In certain embodiments, the distal tip section 4404 of the expandable sheath 4400 may be manufactured according to the methods described below. The distal tip section 4404 disclosed herein may be combined with any of the other embodiments of the sheaths disclosed herein. In some embodiments, the elongated sheet of inner liner layer material shown in FIG. 47 (as described above) is wound in a helical or spiral shape to form an elongated tube that ultimately becomes the inner liner layer 4408, as shown in FIGS. 50-52. A first cut 4444 extends proximally from a distal edge 4432 of the inner liner layer 4408. A second cut 4434 extends perpendicularly from a proximal end of the first cut 4444 to one of a pair of lateral edges 4436 of the inner liner layer 4408.

[0395] The flap 4438 formed by the first and second cuts extends outwardly when the sheet is rolled onto the elongated tubular inner liner layer 4408, as shown in FIG. 63. In one embodiment, the flap 4438 is retained by the remaining uncut portion between the second cut 4434 and the adjacent lateral edge 4436 forming the tab. Thus, the flap is an extension of the sheet that is rolled onto the inner liner layer 4408. The radiopaque marker 4428 can be positioned between the extended flap 4438 and the underlying layer prior to the subsequent heat treatment step, thereby encapsulating the radiopaque marker 4428. In some embodiments, the radiopaque marker is preformed in a C-shape, while in other embodiments, the radiopaque marker is any other shape suitable for being positioned between the flap 4438 and the underlying layer. The flap composition itself can also include a radiopaque compound. Note that the cuts 4444 and 4434 can also be made after rolling the sheet into the inner liner layer 4408 .

[0396] As it is wrapped, an end of the flap 4438 aligns with an interior longitudinally extending edge of the wrapped inner liner layer 4408 and ultimately becomes part of the slit 4412. The flap 4438 is wrapped around the wrapped elongated tube of the inner liner layer 4408 at a slight angle such that the (partially assembled) tip section 4404 tapers toward the distal end 4422 of the sheath 4400. The distal end 4422 of the flap 4438 is trimmed perpendicular to the longitudinal axis. The distal tip section 4404 is wrapped with heat shrink separately from the proximal section 4402 of the expandable sheath 4400. The heat shrink wrap forms and fixes the tapered shape, such as by thinning the wall structure of the inner liner layer 4408.

[0397] The proximal section 4402 and tip section 4404 of the rolled elongated inner liner layer 4408 are placed on a mandrel. Heat is then applied to the distal tip section 4404 during a first reflow step to fuse the flap 4438 to the remaining inner liner layer 4408 of the tip section. As shown in FIGS. 50-52, the area of ​​the previous first cut 4444 is still visible after fusing and reopens to form a portion of the slit 4412. The tab between the end of the second cut 4434 and the adjacent side edge 4436 is cut, as shown in FIG. 63, freeing the proximal section 4402 of the inner liner layer 4408 to expand and fold in a helical or spiral manner.

[0398] In one aspect, as described above, prior to the first reflow step, the radiopaque marker 4428 may be positioned between the flap 4438 and the uncut portion of the rolled inner liner layer 4408. The flap is reflowed over the radiopaque marker 4428, encapsulating the radiopaque marker within the inner liner layer 4408, as shown in Figures 63 and 66. Some thinning and tapering of the material may also occur here (and in other heating and reflow steps), as shown, for example, in Figure 56.

[0399] Next, as shown in FIG 64, the intermediate layer 4426 is positioned at the distal end of the distal tip section 4404 of the inner liner layer 4408 such that the intermediate layer 4426 overlaps a portion of the inner liner layer 4408. In a second reflow step, the intermediate layer 4426 is reflowed (melted) with the inner liner layer 4408 such that the intermediate layer extends proximally onto the outer surface of the inner liner layer. Some thinning of the soft intermediate layer 4426 (and other layers) may also occur in this process, as shown in FIG 61.

[0400] 65, the outer layer 4410 is then partially positioned over the inner liner layer 4408 and a portion of the middle layer 4426 such that a portion of the middle layer extends distally of the outer layer 4410. The outer layer is heat treated to bond with the middle layer 4426 by a third reflow / heat treatment step. In this manner, the middle layer 4408 bonds the outer layer 4410 to the inner liner layer 4408. In some embodiments, the middle layer may be sandwiched between the inner liner layer 4408 and the outer layer 4410 prior to the second reflow step such that the inner liner layer 4408, middle layer 4426, and outer layer 4410 are simultaneously bonded to one another during the second reflow step.

[0401] Once the outer layer 4410 is joined to the distal tip section 4404, a slit 4412 is cut through the inner liner layer 4408, the outer layer 4410, and at least a portion of the tip section's intermediate layer 4426. As shown in FIG. 65, the slit 4412 stops short of the distal end of the intermediate layer 4426, leaving the distal end 4422 of the distal tip section 4404 intact and circumferentially continuous.

[0402] Advantages of the tip section 4404 disclosed above include ease of manufacture, lower force to split the tip without stretching, and cleaner splitting, there are no distal or proximal shoulders formed by the layers, the marker 4428 is embedded in a safe location near the most distal end of the sheath 4400, the spit tip has some dynamic recovery after instrument retrieval, and the middle layer 4426 bonds the outer layer (jacket) well to the inner liner layer and is atraumatic to the body lumen. The tip section 4404 also avoids premature opening during sheath insertion, and the alignment of the edge of the inner liner layer 4408 with the slit 4412 avoids delamination. The outer edge of the scrolled inner liner layer 4408 of the proximal section 4402 is flush behind the tip section 4404, eliminating any distal or proximal facing edges. method

[0403] Aspects of the present disclosure also include a method of making a sheath having a proximal end and a distal end, comprising forming a variable diameter inner liner by winding a sheet having a first edge and a second edge and defined by an inner surface and an outer surface into a spiral 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, thereby forming an overlapping portion, wherein 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, and the inner surface of the sheet defines a lumen of the sheath having a longitudinal axis. forming an outer layer having an inner surface and an outer surface, the outer layer extending around at least a portion of the variable diameter inner liner such that the inner surface of the outer layer is positioned adjacent to the outer surface of the inner liner, the outer layer comprising a braid and a layer of an elastomeric polymer having a predetermined thickness and having an inner surface and an outer surface, the variable diameter inner liner being configured to have a predetermined rest diameter d by sliding a first edge of the sheet along at least a portion of the inner surface and sliding a second edge of the sheet along at least a portion of the outer surface during application of a radially outward force by passage of a medical device through the lumen of the inner liner. r From expansion diameter d eand a step of extending the range of the first and second inputs to the second inputs.

[0404] Various methods can be used to produce the sheaths discussed above and below throughout this disclosure. For example, Figures 7 and 8 illustrate block diagrams of exemplary methods of producing the sheaths in various embodiments. Various method steps are also depicted in Figures 9A-9K and 31. In certain embodiments, as shown in Figure 9A, the inner liner can be formed from an extruded tube 903 having an inner surface and an outer surface and having any of the thicknesses described above. The extruded tube can be cut 905 along its length to form a sheet. In certain embodiments, the inner and / or outer surfaces of the tube can be surface treated, such as, for example, by plasma etching, chemical etching, or other suitable methods of surface treatment. In some exemplary embodiments where the outer surface of the inner liner is treated, the treatment can provide a better bond with the outer layer when formed. In still other embodiments, the inner surface of the inner liner can be ribbed. In these exemplary embodiments, the ribbed surface can promote reduced contact points with the prosthesis, which can reduce friction. In still further embodiments, the initial extruded tube 903 can be produced by co-extrusion with multiple layers of the same or different polymers as described herein. It is understood that one skilled in the art can select the composition of the inner liner depending on the desired application. In certain embodiments, the decision to use a specific material for the inner liner can depend on the desired stiffness, wall thickness, and lubricity optimization. In still other embodiments, as disclosed above, the tube can also be cut to form longitudinal slits 911 (shown in FIG. 31 ) (so that when the formed sheet is rolled, it forms a helical scroll configuration as shown in FIG. 32 ).

[0405] In yet further aspects, an elongated single lumen tube used to form the inner liner has an inner surface and an outer surface, and at least a portion of the outer surface of the elongated single lumen tube includes a first plurality of protrusions and / or at least a portion of the inner surface of the elongated single lumen tube includes a second plurality of protrusions. As the spiral configuration of the inner member is formed, the tube is cut longitudinally around at least a portion of its circumference to form a sheet having a first longitudinal edge and an opposing second longitudinal edge. In such aspects, the cuts are performed such that at least a portion of the first plurality of protrusions is disposed against the first longitudinal edge of the sheet and / or such that at least a portion of the second plurality of protrusions is disposed against the second longitudinal edge of the sheet. In still further exemplary aspects, when the sheet is wound into a spiral configuration, at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, thereby forming an overlapping portion, and at least a portion of the first and / or second protrusions are disposed within the overlapping portion, thereby reducing the contact area between the inner and outer surfaces of the sheet within the overlapping portion. In still further aspects, a tube having a first and / or second protrusions disposed on its outer surface and / or an inner and / or inner surface may be made by any method known in the art. In some aspects, the tube is formed by coextrusion when the first and / or second protrusions are coextruded with the remainder of the sheath. In still further aspects, the first and / or second protrusions may be formed by molding using a die having a desired shape.

[0406] It is understood that embodiments are also disclosed herein in which the second plurality of protrusions are formed on the inner surface of the tube in addition to or instead of the first plurality of protrusions on the outer surface. In such embodiments, for example, when the second plurality of protrusions are formed on the inner surface, the tube is cut so that the second plurality of protrusions abut the second longitudinal edge such that the second plurality of protrusions are also disposed within the overlapping portion when the sheath is in the scroll configuration. It is further understood that when the second plurality of protrusions are present on the inner surface of the sheet, such second plurality of protrusions can include any of the protrusions disclosed above. Similarly, in embodiments in which the second plurality of protrusions are disposed on the inner surface, such second plurality of protrusions can be disposed along at least a portion of the length of the inner liner, or the entire length of the inner liner. Similar to the embodiments in which the first plurality of protrusions are present on the outer surface, when the second plurality of protrusions are present on the inner surface, they can be outside the overlapping portion or even along the entire circumference of the inner liner when in the scroll configuration.

[0407] In yet a further aspect, the elongated single lumen tube used to form the inner liner has an inner surface and an outer surface, and at least a portion of the outer surface of the elongated single lumen tube includes a plurality of bond sites at least partially embedded within the wall of the elongated single lumen tube. When the spiral configuration of the inner member is formed, the tube is cut longitudinally around at least a portion of its circumference to form a sheet having a first longitudinal edge and an opposing second longitudinal edge. In still a further exemplary aspect, when the sheet is wound into the spiral configuration, at least a portion of the inner surface of the sheet overlaps at least a portion of the outer surface of the sheet, thereby forming an overlap. In such an aspect, the outer surface of the sheet within the overlap is substantially free of the plurality of bond sites, while at least a portion of the outer surface of the sheet outside the overlap includes the plurality of bond sites.

[0408] In still further aspects, a tube having multiple bond sites can be made by any method known in the art. In some aspects, the tube is formed by coextrusion when multiple bond sites are coextruded with the remainder of the sheet. In still further aspects, multiple bond sites can be formed by molding using a die having a desired shape.

[0409] In other embodiments, methods are also disclosed where one or more bond sites are located on the inner surface of the outer layer. It is understood that such bond sites may be made by any method known in the art and suitable for the desired application. In certain embodiments, such exemplary bond sites may be formed by coextrusion or molding.

[0410] In still further embodiments, one or more mandrels can be provided (steps 700 or 800 in FIGS. 7 and 8, respectively). The mandrels can be provided with an outer coating, such as a Teflon® coating, and the diameter of the mandrels can be adjusted to the desired rest diameter d of the resulting sheath. r 9B, the sheet formed by cutting 905 the extruded tube 903 can be wound in a spiral configuration around a mandrel 901 (steps 702 and 802 in FIGS. 7 and 8, respectively) to form an inner liner 902a, 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, thereby forming an overlapping portion 902c, with a first edge (not shown) of the sheet being slidable along at least a portion of the inner surface of the sheet and a second edge 902b being slidable along at least a portion of the outer surface of the sheet. When a slit is formed similar to 911 in FIG. 31, the process of winding the sheet around the mandrel is similar, but provides a helical configuration rather than a spiral one.

[0411] In still further exemplary embodiments, in steps 705 and 805 (FIGS. 7 and 8, respectively), a quantity of a first lubricant 910 (FIGS. 9C-9E) can be applied optionally onto the outer surface of the inner liner. The presence of this lubricant material can reduce friction between the inner liner and the outer layer of the final sheath. In still other embodiments, in steps 703 and 803, a quantity of a second lubricant 908 can be applied between the overlapping and sliding portions of the inner liner to further improve slidability and reduce friction. (FIG. 9D depicts an inner liner with two optional lubricants present with the mandrel hidden from view). In still further embodiments, it is understood that the inner liner formed using the mandrel can have any static diameter, as described above. In certain embodiments, the static diameter d r is substantially uniform along the longitudinal axis of the lumen, while in other embodiments, the static diameter d r varies along the longitudinal axis of the lumen and has a rest diameter d at the distal end r The rest diameter at the proximal end, d, is greater than r It is also understood that there are embodiments described herein in which there is no lubricant material between the inner liner and the outer layer.

[0412] In still further aspects, the method may further include providing a braid or coil (steps 704 and 804). It is understood that any of the braids or coils described above may be used in this step. In still further aspects, the braid or coil is mounted on the inner liner as shown in step 706 of FIG. 7. In some exemplary aspects, the braid or coil 904 may be mounted on a first lubricant 910 that may be present on the outer surface of the inner liner as shown in FIG. 9F. It is understood that in some aspects, the second lubricant may be present on only a portion of the outer surface of the inner liner. In still other aspects, the disclosed sheath may have segments where the first lubricant is present and the braid or coil is mounted over it, while other segments where the second lubricant is not present and the braid or coil is mounted directly on the outer surface of the inner liner. It is understood that the location of these specific segments may be determined by one of skill in the art depending on the desired application. It is understood that the mounting of the braid or coil may be performed by any method known in the art. In some non-limiting embodiments, the braid or coil can be provided as a cylindrical tube and slid over an inner liner or first lubricant, if present.

[0413] In still further embodiments, the method may further include providing a layer of elastomeric polymer, as shown in step 708. In such exemplary embodiments, the layer of elastomeric polymer may be used as an outer layer of the sheath. It is understood that any of the elastomeric polymers disclosed above may be used. The particular polymer may be selected based on the desired properties of the disclosed sheath, such as, for example, stiffness, level of hemostasis, etc. The layer of elastomeric polymer may be provided in any form known in the art. In a specific and non-limiting embodiment, the elastomeric polymer may be provided as a cylindrical tube 906 (FIG. 9G). In still further embodiments, the elastomeric polymer may be attached onto an inner liner and a braid or coil (step 710). FIG. 9G depicts an embodiment in which, for example, a cylindrical tube of elastomeric polymer 906 is used to slide over an inner liner having a first lubricant 910 overlying the outer surface of the inner liner and the braid or coil 904.

[0414] In yet further aspects, the disclosed method may include embedding the braid or coil in a layer of elastomeric polymer that serves as the outer layer (step 711, FIG. 7). It is understood that the sheath may comprise various segments. In some aspects, some of the segments may include a braid or coil embedded in a layer of elastomeric polymer, while in other segments, the braid or coil and the layer of elastomeric polymer are separate. It is further understood that in some aspects, the sheath may ...

Claims

1. A sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) for delivering a medical device, wherein the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) has a proximal end and a distal end, A tubular inner liner (915), wherein the tubular inner liner (915) has a longitudinal slit (911) extending along the length of the tubular inner liner (915), the longitudinal slit (911) extending in a direction offset from the longitudinal axis of the tubular inner liner (915) from the proximal end of the tubular inner liner (915) to the distal end of the tubular inner liner (915), and the tubular inner liner (915) is wound in a helical scroll configuration, The longitudinal slit (911) forms a first longitudinal edge and a second longitudinal edge of the tubular inner liner (915), In the helical scroll configuration, at least a portion of the inner surface (915b) of the tubular inner liner (915) helically overlaps at least a portion of the outer surface (915a) of the tubular inner liner (915), the first longitudinal edge of the tubular inner liner (915) being slidable along at least a portion of the inner surface (915b) of the tubular inner liner (915), and the second longitudinal edge being slidable along at least a portion of the outer surface (915a) of the tubular inner liner (915), The inner surface (915b) of the tubular inner liner (915) defines the lumen of the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002), The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) is configured to expand from a static diameter d ｒ to an expanded diameter d ｅ by sliding the first edge of the tubular inner liner (915) along at least a portion of the inner surface (915b) and the second edge of the tubular inner liner (915) along at least a portion of the outer surface (915a) of the tubular inner liner (915) during the application of a radially outward force by the passage of a medical device through the lumen of the tubular inner liner (915). **Claim 2** The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to claim 1, wherein the tubular inner liner (915) is configured to expand without substantially having a gap formed between the first longitudinal edge and the second longitudinal edge of the tubular inner liner (915), and in particular, the tubular inner liner (915) is configured to bend while passing through the natural anatomical structure of a patient without forming a gap between the first longitudinal edge and the second longitudinal edge of the tubular inner liner (915). **Claim 3** The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to claim 1, wherein the direction is diagonal from the proximal end of the tubular inner liner (915) to the distal end of the tubular inner liner (915). **Claim 4** The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to any one of claims 1 to 3, wherein the helical configuration has a predetermined pitch, and in particular, the pitch is at least 4 rotations per 10 cm of the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002).

5. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to any one of claims 1 to 4, wherein the tubular inner liner (915) comprises high density polyethylene, polypropylene, polyamide, fluoropolymer, copolymers thereof, or mixtures thereof, and / or the inner surface of the tubular inner liner (915) is at least partially ribbed, and / or the tubular inner liner (915) is lubricious and has a coefficient of friction of less than about 0.

5.

6. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to any one of claims 1 to 5, further comprising an outer layer (110), in particular, the outer layer (110) comprises polyether block amide, styrenic elastomer, polyurethane, latex, copolymers thereof, mixtures thereof, or extrudates thereof, and more particularly, the outer layer (110) comprises one or more layers (204, 206; 604; 606).

7. The outer layer (110) comprises a first polymer layer, and the first polymer layer has a first compound composition, a first polymer comprising, based on the total weight of the first compound composition, more than 0 wt% to less than 100 wt% of polyether block amide, polyurethane, or a combination thereof, an inorganic filler of less than about 65% based on the total weight of the first compound composition, and a solid lubricant filler of up to about 20% based on the total weight of the first compound composition, and comprises a first compound composition. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) shows at least a 10% reduction in insertion force when compared to a substantially identical reference sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) without the first polymer layer, and the outer layer (110) is substantially torsion-resistant. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to claim 6. **Claim 8** The first polymer includes a polyether block amide elastomer or a polyurethane. In particular, the inorganic filler includes bismuth oxychloride, barium sulfate, basic bismuth carbonate, 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 compound composition. Even more specifically, the solid lubricant includes a PTFE filler. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to claim 7. **Claim 9** The first compound composition further includes at least one adhesion-reducing compound present in an amount of about 1% to about 20% based on the total weight of the first compound composition. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to claim 7 or 8. **Claim 10** The outer layer (110) includes two or more polymer layers. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to any one of claims 7 to 9. **Claim 11** The outer layer (110) comprises at least a second polymer layer comprising a second compound composition comprising a second polymer comprising greater than 0 wt% to 100 wt% of a polyether block amide, polyurethane, or a composition thereof, said second polymer having a Shore A durometer of from about 20 A to about 65 A, the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) of claim 10.

12. The second compound composition further comprises up to 20% tack reducing additive, based on the total weight of the second compound composition, and / or said second polymer comprises polyurethane, the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) of claim 11.

13. The outer layer (110) has a predetermined thickness, at least about 50% of said predetermined thickness comprises the first compound composition and / or the second compound composition, and / or one or more additional polymer layers are disposed between the first polymer layer and the second polymer layer, In particular, said one or more additional polymer layers comprise at least one intermediate reinforcing layer extending axially along at least a portion of the length of the outer layer (110), Even more specifically, said at least one intermediate reinforcing layer comprises the first polymer, the second polymer, a polyolefin-based polymer, or a combination thereof, the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) of claim 11 or 12.

14. The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) further comprises a braided layer (204:604), said braided layer is disposed between the tubular inner layer and the outer layer (110), or The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to any one of claims 6 to 13, wherein the braided layer (204: 604) is at least partially embedded within the outer layer (110). **Claim 15** The sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) according to any one of claims 6 to 14, wherein the sheath (8; 100; 600A; 1200A; 1200B, 1200C; 1200D; 1300C; 1400; 2100; 2002) contains a lubricant that is at least partially disposed between the tubular inner liner (915) and the outer layer (110).

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