Expandable sheath and method of using the same

Abstract

To further improve an introducer sheath for an intravascular system used for implanting heart valves and other prosthetic devices.SOLUTION: Expandable introducer sheaths and methods of making and using the same are disclosed herein. The sheath minimizes trauma to the patient's vasculature by allowing temporary expansion of a portion of the sheath to accommodate passage of a delivery system for the implant and then return to a non-expanded state after passage of the device. The sheath comprises a collapsible inner member having a cut-away flap structure at its distal tip that aids in expanding the sheath lumen to a creased diameter and an elastomeric distal end that reduces push and pull forces therethrough. The sheath can include a hemostatic seal at its proximal end to prevent blood leakage out of the sheath and to prevent balloon expansion of the outer layer of the sheath.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 522,986, filed June 21, 2017, which is incorporated by reference in its entirety for all purposes.

[0002] The present application relates to embodiments of a sheath for use with catheter-based techniques for introducing a prosthetic device, such as a heart valve or other implant, into a patient's vasculature. [Background technology]

[0003] The intravascular delivery catheter assembly is not easily accessible by surgical or invasive procedures. They are used to implant prosthetic devices, such as artificial heart valves, at locations inside the body where non-surgical access is desirable. For example, aortic, mitral, tricuspid, and / or pulmonary valve prostheses can be delivered to the treatment site using minimally invasive surgical techniques, including transcatheter delivery.

[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 that is inserted into the housing through the seal to provide an unobstructed path through the housing for a prosthetic implant, such as a heart valve attached to a 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 involve dilating the vessel with multiple dilators or sheaths of increasing diameter. This repeated insertion and dilation can increase the length of the procedure and increase the risk of injury to the vessel.

[0006] Radially expanding intravascular sheaths maintain a low overall sheath profile to reduce the risk of vessel damage, and such sheaths tend to have complex mechanisms, such as ratcheting mechanisms, that maintain the shaft or sheath in the expanded configuration when a device with a diameter larger than the original diameter of the sheath is introduced. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent Application No. 14 / 880,109 [Patent Document 2] U.S. Patent Application Serial No. 14 / 880,111 [Patent Document 3] U.S. Patent Application No. 62 / 449,454 Summary of the Invention [Problem to be solved by the invention]

[0008] However, delivery and / or removal of prosthetic devices and other instruments to and from patients poses risks to the patient. Furthermore, vascular access remains a challenge due to the relatively large profile of delivery systems, which can cause longitudinal and radial tearing of the vessel during insertion. The delivery system may further dislodge calcified plaque within the vessel, creating an additional risk of blood clots caused by the dislodged plaque. The added radial expansion property may also hinder the practitioner's ability to push the sheath, preventing it from bending or kinking. Therefore, there remains a need for further improvements in introducer sheaths for endovascular systems used to implant heart valves and other prosthetic devices. [Means for solving the problem]

[0009] Disclosed herein are expandable introducer sheaths and methods of making and using the same. The expandable introducer sheaths disclosed herein are used to deliver prosthetic devices through a patient's vasculature to an internal surgical site. The sheaths are configured to be highly circumferentially expandable and collapsible while also minimizing the sheath wall thickness to minimize the profile of the delivery system. Additionally, the sheaths disclosed herein benefit from the use of flaps instead of folded configurations to reduce tip thickness while simultaneously reducing the expanded diameter by 30% or more for passage of implants. The present invention also includes a distal tip assembly that allows for expansion. A flap assembly at the distal tip can also enhance ease of expansion for balloon and implant removal. Additionally, a proximally located seal for accommodating blood leaks between the outer elastomeric layer and the inner folded layer is disclosed herein. The proximal location of this seal reduces layers, protuberances, and asymmetries at the tip, and preferably the seal is marked for placement at or near the site of entry into the patient's vasculature for balloon expansion or leak accommodating. The seal assembly can also include an outer jacket that enhances visibility of the seal location and prevents balloon expansion adjacent to the seal.

[0010] Some embodiments include an expandable sheath having an elongate inner member and an elastomeric outer member. The elongate inner member defines a central lumen and first and second circumferential portions. The first circumferential portion includes first and second longitudinal edges. The second circumferential portion extends between the first and second longitudinal edges. The elongate inner member is configured to be folded at the first and second longitudinal edges. In the folded configuration, the second circumferential portion is at least partially disposed between the overlapping edges. The outer elastomeric member extends around the elongate inner member and is configured to bias the elongate inner member into the folded configuration. The elongate inner member also includes a distal tip. The distal tip includes a flap extending from the first longitudinal edge to at least the second longitudinal edge to position the elongate inner member in an open (or at least partially unfolded) configuration.

[0011] In other embodiments, the flap is configured to slide circumferentially over the outer surface of the first circumferential portion when the elongate member is biased into the folded configuration by the elastic member. The second circumferential portion can have a distal edge extending longitudinally at least to the proximal edge of the flap. The proximal edge of the flap can extend over the distal edge of the second circumferential portion onto the outer surface of the second circumferential portion.

[0012] In another embodiment, the flap can include a longitudinal section of the second circumferential portion cut along the second longitudinal edge, which may also be cut circumferentially from a distal end of the second circumferential portion.

[0013] In other embodiments, the expandable sheath can also include overlapping extensions. For example, the overlapping extensions can extend circumferentially from the longitudinal section, or the overlapping extensions can extend proximally from the longitudinal section.

[0014] In other embodiments, the distal tip can further comprise an elastomeric tip extending from the distal end of the inner elongate member. The elastomeric tip can include a distal taper. The distal tip can also include a marker embedded therein, such as within the inner member.

[0015] A method of making a distal tip of an expandable sheath is also disclosed. The method includes forming a folded configuration on an elongate inner member by forming creases along a first longitudinal edge and a second longitudinal edge of the elongate inner member. A first circumferential portion is at least partially disposed between the longitudinal edges in the folded configuration. The method also includes forming a flap on the distal tip of the inner member such that the flap extends from the first longitudinal edge of the inner member to at least the second longitudinal edge of the inner member. The method further includes covering the elongate inner member with an elastomeric outer member.

[0016] The method may include other embodiments, such as extending the flap circumferentially over the outer surface of the first circumferential portion when forming the flap. The step of forming the flap may include forming a proximal edge of the flap over a distal edge and extending onto the outer surface of the second circumferential portion. The method may also include the step of: The flap may be at least partially formed by cutting the longitudinal section from the second circumferential portion; and the flap may be at least partially formed by attaching the overlapping extension to the longitudinal section.

[0017] The method may also include attaching an elastomeric end to the distal end of the inner elongate member, and the method may include forming a tapered shape in the elastomeric end.

[0018] In another embodiment, a method for delivering a prosthetic device, such as a heart valve, is disclosed. The method can include positioning an expandable sheath within a patient's vasculature. The method then includes introducing the prosthetic device through a lumen of the expandable sheath such that the prosthetic device exerts a radially outward force on an inner surface of an inner member of the expandable sheath, locally expanding the inner member to an expanded configuration. The method also includes advancing the prosthetic device further through the lumen to a distal tip of the expandable sheath, and sliding a free end of a flap at the distal tip circumferentially over an outer surface of a first circumferential portion of the expandable sheath in response to radial pressure exerted by the passage of the prosthetic device, locally expanding the lumen. In another aspect, the inner member can be collapsed at the distal tip after the prosthetic device has passed out of the lumen.

[0019] In other embodiments, the method can include advancing a prosthetic device through an elastomeric end that extends around the distal end of the lumen, expanding the elastomeric end and at least partially collapsing the elastomeric end after the prosthetic device has passed therethrough.

[0020] In other embodiments, the method may include at least partially collapsing the inner member by sliding a free end of a flap at the distal tip circumferentially over an outer surface of the first circumferential portion to locally reduce the diameter of the lumen.

[0021] Another embodiment includes an expandable sheath with a proximal seal. For example, the expandable sheath can include an elongate inner member, an elastomeric outer member, and a proximal seal. The elongate inner member includes at least one collapsible shaft segment. The outer elastomeric member extends at least partially over the inner member and is configured to exert a compressive force on the inner member to bias the at least one collapsible shaft segment into a collapsed configuration. The proximal seal includes an intermediate member extending from an outer surface of the inner member to an inner surface of the outer elastomeric member. Advantageously, the seal is configured to prevent proximal migration of fluid from the distal free end of the expandable sheath to the proximal end of the expandable sheath.

[0022] In other embodiments, the inner and outer elastomeric members can have an unconnected length distal to the proximal seal. For example, the unconnected length can extend distally from the proximal seal to the free distal end of the expandable sheath. The seal thus prevents leakage by blocking a path beginning at the distal free end and extending proximally along the unconnected length.

[0023] In yet other embodiments, the expandable sheath can include an outer jacket extending over the outer elastomeric member at the proximal seal. The outer elastomeric member can then be fused to the inner member at the seal. The outer elastomeric member can also be collapsible with the inner member at the proximal seal. Distal to the seal, the inner member can also be collapsible independently of the outer elastomeric member. The elongate inner member, in either or both instances, can at least partially expand the open configuration for passage of an implant. It can also be configured to:

[0024] In other embodiments, the elongate inner member defines a central lumen, a first circumferential portion including first and second longitudinal edges, and a second circumferential portion extending between the first and second longitudinal edges, and the elongate inner member may be configured to be creased at the first and second longitudinal edges into a folded configuration, with the second circumferential portion being at least partially disposed between the overlapping longitudinal edges.

[0025] In other embodiments, the inner elongate member can include a distal tip comprising a flap extending from a first longitudinal edge to at least a second longitudinal edge in the open configuration of the inner elongate member.

[0026] In another embodiment, the expandable sheath can include a proximally disposed strain relief portion, and the proximal seal can have a proximal end adjacent the distal end of the strain relief portion. The strain relief portion can have a length that is, for example, at least 9.5 cm long.

[0027] In another embodiment, a method or process for making an expandable sheath having a proximal valve is disclosed. The method includes forming a folded configuration on an elongate inner member. For example, forming folds along first and second longitudinal edges of the elongate inner member such that a first circumferential portion is at least partially disposed between the longitudinal edges in the folded configuration. There is then the step of covering the elongate member with an elastomeric outer member. The method may also include forming a proximal seal proximal to the distal free end of the expandable sheath by extending an intermediate member from an outer surface of the inner member to an inner surface of the elastomeric outer member.

[0028] The method can further include blocking a pathway extending from the distal free end and extending between the inner and outer members with a proximal seal to block leakage, and can further include fusing the elastomeric outer member to the inner member at the seal.

[0029] For example, fusing can include stretching an outer jacket over the outer elastomeric member at the proximal seal, and the method can include stretching the inner member and the elastomeric outer member over the mandrel into an open configuration before fusing.

[0030] Another embodiment includes a method of delivering a prosthetic device. The method includes positioning an expandable sheath within a patient's vasculature up to a proximal seal on the expandable sheath, and further includes introducing the prosthetic device into the lumen of the expandable sheath. The method can also include blocking a leak path beginning at the distal free end of the expandable sheath with the proximal seal. The method also includes advancing the prosthetic device through the lumen of the expandable sheath such that the prosthetic device exerts a radially outward force on an inner surface of an inner member of the expandable sheath, locally expanding the inner member to an expanded configuration. The delivery method then includes at least partially collapsing the inner member at its distal tip after the prosthetic device has passed out of the lumen of the expandable sheath.

[0031] In other embodiments, the method includes at least partially blocking the pathway with a proximal seal that uses an intermediate layer extending between the inner member and the outer elastomeric member. [Brief explanation of the drawings]

[0032] [Figure 1A] FIG. 1 is a side view of a delivery device for deployment through a sheath. [Figure 1B] FIG. 1 is a side view of a delivery device for deployment through a sheath. [Figure 1C] FIG. 1 is a side view of an expandable introducer sheath. [Figure 2] FIG. 1 is a perspective view of an expandable introducer sheath. [Figure 3] FIG. 12 is a cross-sectional view of the distal tip of an expandable introducer sheath. [Figure 4]10A-10C illustrate steps in the manufacturing process for an introducer sheath (sheath shown in expanded configuration) including cutting the flaps. [Figure 5] 10A-10C illustrate another step in the manufacturing process for an introducer sheath, which involves folding the sheath into a collapsed configuration and cutting a gap into the distal end of the sheath. [Figure 6] 10A-10C illustrate another step in the manufacturing process for an introducer sheath (sheath shown in collapsed configuration) including attaching flap extensions. [Figure 7] 5A and 5B show an extended overlap for attachment to a cutting flap such as the cutting flap shown in FIG. 4. [Figure 8] 10A-10C illustrate another step in the manufacturing process involving attachment of the bilayer strip to the foldable inner member. [Figure 9] 10A-10C illustrate another step in the manufacturing process involving sealing together the tip and outer member of the expandable introducer sheath. [Figure 10] FIG. 10 is an end view of the overlapping inner member and flap portion of the expandable introducer sheath without the elastomeric free end attached. [Figure 11] FIG. 13 is a perspective view of the distal tip of the sheath without the outer member and before attachment of the elastomeric free end. [Figure 12] FIG. 10 is a side view of the profile of the distal tip of the expandable introducer sheath in the collapsed configuration on the mandrel. [Figure 13] FIG. 13 is an enlarged view of the leading edge of the sheath shown in FIG. 12. [Figure 14] FIG. 1 is a schematic diagram of an expandable introducer sheath having a proximally positioned seal. [Figure 15] FIG. 10 is a cross-sectional view of an extruded inner member having a foldable thin-walled section. [Figure 16] 16 is a cross-sectional view of the inner member of FIG. 15 in a collapsed configuration. [Figure 17]FIG. 1 is a cross-sectional view of an expandable introducer sheath having a collapsible inner member and an elastomeric outer member. [Figure 18] FIG. 10 is a cross-sectional view of an expanded or dilated introducer sheath over a mandrel. [Figure 19] 1 is a cross-sectional view of an expanded or dilated introducer sheath with the inner and outer members joined together. FIG. [Figure 20] FIG. 20 is a cross-sectional view of the introducer sheath of FIG. 19 in a collapsed configuration. [Figure 21] FIG. 21 is a cross-sectional view of the introducer sheath of FIG. 20 including an outer jacket. [Figure 22A] FIG. 1 is a schematic diagram of an expandable introducer sheath with the proximal valve withdrawn from the patient. [Figure 22B] FIG. 1 is a schematic diagram of an expandable introducer sheath with the proximal valve withdrawn from the patient. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following description of some examples of the inventive concepts should not be used to limit the scope of the claims. Other examples, features, aspects, embodiments, and advantages will become apparent to those skilled in the art from the following description. As will be appreciated, the device and / or method are capable of all other different and obvious aspects without departing from the spirit of the inventive concepts. Accordingly, the drawings and description should be regarded as illustrative in nature and not restrictive.

[0034] For purposes of description, certain aspects, advantages, and novel features of embodiments of the present disclosure have been described herein. The described methods, systems, and apparatus are not intended to be limiting. Instead, the present disclosure is directed to all novel and unobvious features and aspects of the various disclosed embodiments, both alone and in various combinations and subcombinations with one another. The disclosed methods, systems, and apparatus are not limited to any particular aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more particular advantages be present or problems be solved.

[0035] It is understood that any feature, integer, attribute, compound, chemical moiety, or chemical group in connection with a specific aspect, embodiment, or example of the invention may be applicable, to the extent not incompatible, to any other aspect, embodiment, or example described herein. All features disclosed herein (including any accompanying claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except for combinations in which at least some of such features and / or steps are incompatible. The invention is not limited to the details of any foregoing embodiment. The invention extends to any novel, or any novel combination of features, disclosed herein (including any accompanying claims, abstract, and drawings), or to any novel, or any novel combination of steps of any method or process so disclosed.

[0036] Any patent, publication, or other disclosure material that is said to be incorporated by reference herein, in whole or in part, should be understood to be incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. Thus, to the extent necessary, the present disclosure as expressly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portions thereof, that is said to be incorporated herein by reference but that conflicts with existing definitions, statements, or other disclosure material set forth herein is incorporated only to the extent that no conflict arises between the incorporated material and the existing disclosure material.

[0037] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "approximately" one particular value and / or to "approximately" 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 will be further understood that the endpoints of each range are significant both in relation to the other endpoint, and independently of the other endpoint.

[0038] "Optionally" or "optionally" means that the subsequently described event or circumstance may or may not occur, and the description includes instances in which the event or circumstance occurs and instances in which it does not occur.

[0039] Throughout the description and claims of this specification, the word "comprise" and variations of this word, such as "comprising" and "comprises," mean "including, but not limited to," and are not intended to exclude, for example, other additives, components, integers, or steps. "Exemplary" is "an example" of a preferred or ideal embodiment and is not intended to convey an indication of a preferred or ideal embodiment. "Such as" is not used in a limiting sense but for illustrative purposes.

[0040] As used herein, the terms "proximal" and "distal" refer to the location of a sheath, catheter, or the region of the delivery assembly. "Proximal" means the region closest to the handle of the device, while "distal" means the region furthest from the handle of the device.

[0041] As used herein, the terms "tube" or "tubular" are not meant to limit the shape to a circular cross-section. Instead, tube or tubular may refer to any elongated structure having a closed cross-section and a lumen extending axially therethrough. A tube may have some selectively provided slots or openings therein, but the tube still provides a closed structure for accommodating other components within the lumen.

[0042] The expandable introducer sheath disclosed herein is used to deliver prosthetic devices through a patient's vasculature and into the patient's body to an internal surgical site. The sheath is configured to be highly circumferentially expandable and collapsible while also minimizing the sheath wall thickness to minimize the profile of the delivery system. Furthermore, the sheath disclosed herein benefits from the use of flaps instead of folded configurations to reduce the number of layers at the tip to two or three, while simultaneously allowing the expanded diameter to be increased by 30% or more for implant passage. The flap assembly at the distal tip can also enhance the ease of expansion for balloon and implant retrieval through the expandable sheath. Furthermore, a proximal seal is disclosed herein to prevent blood leakage between the outer elastomeric layer and the inner folded layer at the distal tip (blood between the layers due to the free edge of the flap). The proximal location of this seal reduces layers, bulges, and asymmetries at the distal tip of the sheath, and preferably the seal is marked for placement at or near the entrance into the patient's vasculature to accommodate balloon expansion or leaks. The seal assembly can also include an outer jacket that enhances visibility of the seal location and prevents balloon expansion adjacent to the seal.

[0043] 1A-1C illustrate an expandable sheath 10 according to the present disclosure and an exemplary delivery device 110 for delivering a prosthetic implant, such as a prosthetic heart valve, to a patient. It should be understood that the delivery device 110 described herein is exemplary only, and that other similar delivery systems may be used with the expandable sheath 10. The delivery device 110 shown herein generally includes a steerable guide catheter 114 and a balloon catheter 116 extending through the guide catheter 114.

[0044] 1A-1B, a guide catheter 114 and a balloon catheter 116 are adapted to slide longitudinally relative to one another, thereby facilitating delivery and placement of a prosthetic heart valve at an implantation site within a patient's body. Guide catheter 114 includes a handle portion 120 and an elongated guide tube, or shaft 122, extending from handle portion 120 (FIG. 1B).

[0045] FIG. 1C shows an expandable sheath 10 used to introduce a delivery device 110 and a prosthetic device into a patient's body. The expandable sheath 10 has a generally tubular configuration defining a central lumen that guides the passage of a delivery system for a prosthetic heart valve. At its proximal end, the expandable sheath 10 includes a hemostatic valve that prevents leakage of pressurized blood. Generally, during use, the distal end of the sheath 10 is passed through the patient's skin, and the sheath 10 is inserted into a blood vessel, such as the femoral artery. The delivery device 110 (together with its implant) is then inserted into the sheath 10 through the hemostatic valve and advanced through the patient's vasculature to the location where the implant will be delivered and implanted within the patient.

[0046] In one embodiment, as shown in Figure 2, sheath 10 comprises an elongate inner member 20 and an outer elastomeric member 50 extending along a common central longitudinal axis. Figure 3 shows a cross-sectional view of the distal tip of expandable sheath 10, and Figure 4 shows the sheath in a circumferentially expanded state during manufacturing steps. A side view of its distal tip is shown in FIG. 4 . As shown in FIG. 4 , the elongate inner member 20 comprises a first circumferential portion 24 separated from a second circumferential portion 26 by a pair of folds or creases 22. The creases 22 facilitate folding the elongate member into a folded configuration. In one embodiment, the flap 30 can be cut from the second circumferential portion 26 of the inner member 20 by the following procedure: The crease 22 (corresponding to the edge 38 of the second circumferential portion 26) is cut axially to create the free edge 46 of the flap 30. A second cut is made approximately perpendicular to the (circumferential) free edge 46 to form the proximal edge 44 of the flap 30. This second cut simultaneously forms the distal edge 58 of the second circumferential portion 26. At this point, the flap 30 comprises a cut portion of the second circumferential portion 26 including a distal edge 42 , a proximal edge 44 , and a free edge 46 .

[0047] The structure of the distal tip 28 and its flap 30 allows for a lower profile than prior art devices with assembled tips. However, the flap 30 also allows for increased extensibility, as the flap 30 slides freely along the outside of the first circumferential portion 24. In some embodiments, the flap 30 is extended proximally and circumferentially with an extended overlap 60 that extends over the flap 30, allowing it greater movement relative to the first circumferential portion 24. Such an extended overlap is shown alone in FIG. 7 and attached to the sheath 10 in FIGS. 6 and 8, and is described in detail below. In another embodiment, the flap 30 can include a radiopaque marker band 52 that is applied, embedded, or otherwise coupled to the flap 30 for locating the distal tip of the sheath 10 within a patient's body using fluoroscopy.

[0048] Although embodiments of the distal tip structure and proximal seal of the present invention are shown as part of a sheath with an inner folding member and an elastic outer member, other types of expandable introducer sheaths may benefit from such improvements. For example, commonly assigned U.S. patent application Ser. Nos. 14 / 880,109 (the '109 application, entitled Expandable Sheath), 14 / 880,111 (the '111 application, entitled Expandable Sheath Having an Elastomeric Cross-Sectional Portion), and 62 / 449,454 (the '454 application, entitled Expandable Sheath), each of which is hereby incorporated by reference in its entirety, disclose expandable introducer sheaths that may benefit from embodiments of the present invention.

[0049] In the disclosed embodiment, the sheath 10 can include an outer elastomeric member 50 that encases at least a portion of the length of the expandable sheath 10. An example of an outer elastomeric member 50 is shown in Figures 1C and 2. The outer elastomeric member 50 can be formed from a variety of elastomeric materials, such as polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and composite materials reinforced with carbon or glass fibers. Preferably, the outer elastomeric member 50 is formed from a biocompatible anticoagulant material.

[0050] When extending around the outside of the sheath 10, the outer elastomeric member 50 provides an inwardly directed radial force that acts as a locking mechanism to prevent longitudinal slippage between the various layers of the expandable sheath 10. The compressive force provided by the outer elastomeric member 50 can also facilitate movement of the circumferential portions of the sheaths 24, 26 back toward the central longitudinal axis of the sheath 10 after expansion by a passing prosthetic device. Thus, the sheath 10 is configured to allow localized expansion of the sheath 10 in the presence of an implant, and then return to its smaller, unexpanded diameter after the implant has passed. Finally, the outer elastomeric member 50 provides a smooth surface that can minimize damage to the vasculature as the sheath 10 is positioned and during insertion of a delivery system and implant therethrough. A similar inner lumen extending through the sheath 10 can be used to prevent a passing prosthetic device from being damaged by the sheath 10 and to reduce friction between the sheath 10 and the device during its passage. It is contemplated that side elastomeric members (not shown) may be included.

[0051] Embodiments of the present invention are not limited to the specific elastomeric members illustrated herein. For example, the '109, '111, and '454 applications, incorporated herein by reference, disclose other structures, materials, and configurations for the outer elastomeric member 50. Also, while the illustrated embodiment of the outer elastomeric member 50 has a circular cross-sectional shape, other shapes are possible, such as oval, square, and mixed or irregular shapes that define some total or partial lumen through which the implant delivery device can extend. Furthermore, the terms "circumferential" or "circumferential," or "tube" or "tubular," as used herein, are not limited to a circular cross-section, but instead extend to the complete or partial periphery of a shape that defines a complete or partial lumen for the passage of other layers or implants.

[0052] FIG. 15 shows a cross-section of inner member 20 in an expanded configuration, illustrating a circular cross-section of inner member 20 including first and second circumferential portions 24, 26. FIG. 16 provides a cross-section of inner member 20 in a folded configuration, illustrating circumferential portions 24, 26 separated from one another by a pair of fold lines or creases 22. Fold lines 22 extend longitudinally along most of the length of inner member 20 (as shown in FIG. 4 and described above). For example, first circumferential portion 24 includes first and second longitudinal edges 36, 38 formed by or extending along fold lines or creases 22. Second circumferential portion 26, at least in the embodiment shown, has its own longitudinal edge 40 formed by fold line 22, as it completes the circumference of inner member 20.

[0053] The fold lines 22 need not be straight or continuous along the length of the inner member 20. The fold lines 22 may terminate, for example, at or near an extended strain relief section for connection to a hub at the proximal end of the sheath 10. The distal tip configuration may also include removal or modification of such fold lines. The fold lines 22, in the illustrated embodiment, are formed by a reduction in wall thickness between the first and second circumferential portions 24, 26. The fold lines 22 may also be formed by scoring, conditioning, compositional modification, etc., to facilitate compressing the inner member 20 into a compressed, folded configuration, as shown in FIG. 16 , before or after passage of an expanding implant.

[0054] In one embodiment, the first circumferential portion 24 occupies a much greater percentage of the arc or circumference of the inner member 20. For example, as shown in FIG. 15 , the first circumferential portion 24 occupies more than three-quarters (270 degrees) of the circular cross-section of the inner member 20. Conversely, the second circumferential portion 26 occupies approximately one-quarter or less of the remaining circumference of the inner member 20. The ratio of the first and second circumferential portions 24, 26 may be varied to accommodate the desired amount of reduction in profile of the inner member 20 and the remaining sheath 10. However, in general, the indicated ratios work well to balance the amount of profile reduction provided by the thinner second circumferential portion 26 with the thicker first circumferential portion 24, which is sufficient to push the sheath 10 to deliver stent-mounted heart valves and other prosthetic implants.

[0055] 16 and 17 , the inner member 20 has a folded configuration in which the first longitudinal edge 36 of the first circumferential portion 24 overlaps the second longitudinal edge 38. Specifically, the fold lines 22 facilitate folding of the elongated inner member 20 into an overlapping configuration, for example, with the aid of the elastomeric characteristics of the outer elastomeric member 50. In the overlapping configuration, the longitudinal edges 36, 38 (along the fold lines 22) of the first circumferential portion 24 come together and pass each other in an overlapping arrangement. This arrangement also traps or folds some or all of the second circumferential portion 26 between the overlapping edges of the first circumferential portion 24 to keep the profile of the expandable introducer sheath 10 low.

[0056] Preferably, the inner member 20 is constructed from a tube of a relatively stiff material (compared to the outer elastomeric member 50), such as a rigid polymer, such as high-density polyethylene (HDPE) or an equivalent polymer. A unitary construction, such as a unitary extrusion of the wall portion, is advantageous in preventing leaks in prior art sheaths that use splits in the sheath to facilitate expandability. Also, while the embodiment of the outer elastomeric member 50 shown in the figures has a circular cross-sectional shape, other shapes are possible, such as oval, square, and mixed or irregular shapes, so long as some form of lumen is formed through which an implant delivery device can pass. The '109, '111, and '454 applications, incorporated herein by reference, disclose other structures, materials, and configurations for the elongate inner member 20 that can be used with the expandable sheaths disclosed herein.

[0057] As shown in FIGS. 3-6, 9, and 11, the distal tip 28 of the expandable sheath in one embodiment includes a flap 30 that extends a short length along the distal end of the expandable sheath 10 and terminates in an elastomeric free end 54. FIG. 4 shows the inner member 20 in an expanded state during manufacturing. The illustrated flap 30 generally begins at its connected edge 48, which is located adjacent to the first longitudinal edge 36 of the first circumferential portion 24. For example, as shown in FIG. 4, the flap 30 extends circumferentially toward the second longitudinal edge 38. As shown in FIG. 5, when the sheath is collapsed, the flap 30 extends over the second longitudinal edge 38 and back onto the outer surface of the first circumferential portion 24. Generally, the amount of overlap beyond the longitudinal edge 38 is determined by the maximum profile of the implant and delivery system.

[0058] The flap 30 includes a distal edge 42, a proximal edge 44, and a free edge 46 extending between the distal and proximal edges 42, 44. A top or connected edge 48 is formed where the flap transitions into or attaches to the first circumferential portion 24. These four edges are generally straight and connected at right angles to form a generally rectangular shape for the flap 30 (with some rounded corners in some embodiments). Generally, the flap 30 enhances the expandability of the distal tip 28 as the flap 30 slides freely along the outer surface of the first circumferential portion 24. As shown in FIGS. 10-11 , the distal edge 42, proximal edge 44, and free edge 46 slide or move freely with the expansion and compression (folding) of the inner member 20.

[0059] The configuration of distal tip 28 advantageously avoids the need to build up multiple layers used in conventional tip structures. For example, the flap region of distal tip 28 includes only three layers: elastomeric outer elastomeric member 50, flap 30, and one of the underlays of first or second circumferential portions 24, 26 of inner member 20. In one embodiment, flap 30 has an axial length along free edge 46 of approximately 23+5 mm and a circumferential length at distal and proximal edges 42, 44 of approximately 12+2 mm.

[0060] The flap 30 of the present invention may vary in shape and size, such as square, semicircular, or other irregular shapes, so long as a portion of the flap 30 extends axially and / or circumferentially far enough to achieve some level of overlap with the first circumferential portion 24, at least in a compressed state. The flap 30 can take many forms, such as cut sections of other closed circumferential shapes that allow temporary expansion to allow the passage of an implant. Alternatively, as described above, the flap 30 can comprise a combination of materials assembled to different degrees of extension or overlap, providing the distal tip 28 with improved expandability while preventing catching when regaining its unexpanded or compressed configuration. While particularly advantageous when combined with the collapsible sheath and valve assembly disclosed herein to prevent fluid leakage, the flap 30 need not be associated solely with a collapsible sheath.

[0061] Preferably, the elastomeric free end 54 of the distal end 28 of the expandable sheath 10 is attached to the distal end of the first circumferential portion 24 and extends distally therefrom, as shown in FIG. The elastomeric free end 54 has a tubular shape and tapers distally. Unlike the freely sliding flap 30, the free end 54 has sufficient elastomeric properties to extend to create a lumen large enough to pass an implant. Due to its annular shape, the free end 54 somewhat restricts the free expansion of the flap 30 relative to the rest of the inner member 20. Thus, the annular shape of the free end 54 can prevent the flap 30 from displacing too far and being unable to return using the outer elastomeric member 50 alone. The elastomeric free end 54 can be composed of any elastomeric material with sufficient high elasticity and fatigue resistance to manage the expansion and return of the sheath 10 to its expanded diameter. One example of such a material is NEUSoft™ thermoplastic polyurethane. As shown in FIG. 9 , the elastomeric free end 54 can also include a portion of the outer elastomeric member 50 joined to the annularly configured bilayer of NEUSoft™ and tapered at its distal end.

[0062] As shown in FIGS. 3-9, the expandable introducer sheath 10 can be constructed using a process that involves cutting the inner member 20, forming the structure for the flaps 30 as described above, and then joining the various layers together to form the distal tip 28. A radiopaque marker band 52 can be affixed, glued, or tacked onto the inner member 20 near its distal end. Additionally, as shown in FIGS. 9 and 11, a bilayer strip 62 formed from layers 64, 66 can be tacked to the distal edge of the inner member 20 to form part of the elastomeric free end 54. The bilayer strip 62 has a circumferential length that is the same as the circumferential length of the first circumferential portion 24. Thus, the bilayer strip 62 does not form a complete tubular layer in the expanded configuration (as shown in FIG. 11). A pair of longitudinally extending free edges 82 of the bilayer strip 62 are brought together in a folded configuration and joined together with the distal end of the outer elastomeric member 50 to form a generally annular elastomeric free end 54 (as shown in FIG. 9 ). The free edges 82 are then removed to create a widening gap 84 that extends slightly distally.

[0063] FIG. 8 shows a cross section with a bilayer strip 62 disposed on the outside and having an outer layer 64 extending distally past an inner layer 66. Both layers 64, 66 are disposed flush with one another at the proximal edge of the bilayer strip 62. The proximal edge of the bilayer strip 62 is heat tacked onto the distal ends of the inner member 20 and flap 30. The outer layer 64 can be thinner but axially longer than the inner layer 66. For example, the outer layer 64 can be 0.007 inches thick and 6 mm long. For example, the inner layer 66 can be 0.012 inches thick and 3 mm long. When stacked together, the combined thickness of the bilayer strip 62 is slightly greater (by 0.002 inches) than the first circumferential portion 24 (which is 0.012 inches thick) and the distal end of the overlapping flap 30, which is 0.005 inches thick. The inner surface of the inner layer 66 and the first circumferential portion 24 are preferably flush with one another for a smooth inner lumen.

[0064] As a further improvement, an extended overlap portion 60, such as that shown in FIG. 7, may be attached to the tear flap 30. The extended overlap portion 60 has a rectangular body 68 formed of the same or similar material as the inner member 20, such as high-density polyethylene (HDPE), a small tab 70, and a large tab 72. In one embodiment, the rectangular body 68 is approximately 11 mm by 23 mm and includes a proximal rounded corner 74. The small tab 70 extends circumferentially from the rectangular body and includes a proximal rounded corner 74. The small tab 70 has a rectangular shape and extends 3 mm circumferentially from the circumferential edge of the rectangular body 68 and 5 mm longitudinally. The large tab 72 also extends circumferentially from the rectangular body 68. The large tab 72 has a rectangular shape and extends 12 mm circumferentially and has an axial length of 7 mm. Overall, then, the extended overlap portion 60 has a U-shape with a long arm (large tab 72) and a short arm (small tab 70) that are configured to engage and extend the rectangular outer edge of the flap 30 cut from the second circumferential portion 26.

[0065] As shown in FIG. 6, the extended overlap 60 is secured (e.g., by heat riveting) to the second circular The tab 70 is attached to the flap 30 cut from the perimeter portion 26 to form the composite flap 30. The large tab 72 and rectangular body 68 are layered over the distal portion of the cut flap 30, covering the radiopaque marker band 52 and thereby forming the distal edge 42 of the flap 30. The small tab 70 and rectangular body 68 abut, but do not overlap, edges, thereby extending the proximal edge of the cut flap to form the proximal edge 44 of the flap 30. The longitudinally extending edge of the body 68 forms the free edge 46 of the flap 30.

[0066] Advantageously, the extended overlap 60 provides for greater circumferential expansion, with the flap 30 extending over the second longitudinal edge 36 (formed by the fold 22) of the first circumferential portion 24, thus covering the gap formed by cutting the flap from the second circumferential portion 26. As shown in FIG. 6 , this extends the extent of the flap 30, allowing for greater movement relative to the first circumferential portion 24 during expansion of the inner member 20. The flap 30 also extends axially proximally over the distal cut edge 58 of the second circumferential portion 26.

[0067] An additional bilayer tab 80 may be tacked to the proximal edge of the tear flap 30 and circumferentially adjacent to the free end of the small tab 70. In FIG. 6 , for example, the bilayer tab 80 has an axially extending edge 81 joined to and extending circumferentially away from the top or free edge of the small tab 70. The bilayer tab 80 also has a distal edge 83 joined to the proximal edge of the tear tab 30. The bilayer tab 80 is also at least partially joined to the outer surface of the substrate first circumferential portion 24. The bilayer tab 80 has an elastomeric composition that facilitates a smooth transition between the tear flap and the inner member 20 at the adjacent first and second circumferential portions 24, 26, as it is joined to and connects to the stiffer first circumferential portion 24 and flap 30 and flap extension 60. The bilayer tab 80 can have a rectangular shape, such as a 2 mm by 5 mm rectangle, and layer thicknesses of 0.007 inches and 0.012 inches. Other shapes, sizes, and thicknesses can be made to manage the transition between the flap and the adjacent inner member, but matching thicknesses and the use of elastomeric materials have advantages for improved smoothness and resilience.

[0068] 8 and 9, a cross section shows that the large tab 72 of the extended overlap 60 (having a thickness of 0.005 inches) is attached to the upper surface of the first circumferential portion 24 (having a thickness of 0.012 inches) of the substrate supporting the marker band 52. Then, as described above, the proximal edge of the two-layer strip 62 is tacked to the distal edge of the laid composite flap 30. Advantageously, the above-described structure facilitates a smooth transition between the flap 30 with the extended overlap 60 and the inner member 20.

[0069] As shown in FIG. 9 , outer elastomeric member 50 is then placed over the structure of inner member 20 and distal tip 28, which is disposed on mandrel 86. (The formation of the proximal portion of sheath 10, including a wider diameter proximal strain relief end, is shown in the '109, '111, and '454 applications, which are incorporated herein by reference.) To facilitate the tapering of the wall thickness of sheath 10, outer elastomeric member 50 does not extend to the distal edge of bilayer strip 62.

[0070] On mandrel 86, outer elastomeric member 50 is bonded to bilayer strip 62, which is fully fused to the distal edge of inner member 20, thereby forming the annular structure of elastomeric free end 54. Preferably, mandrel 86 is tapered to facilitate closure of overlapping gap 84 between free edges 82 of bilayer strip 62 and formation of the smoothly tapering frustoconical shape of the distal tip of the sheath (shown in FIG. 2) during bonding.

[0071] A portion of the thinner outer layer 64 of the bi-layer strip 62, such as an additional approximately 0.5 mm to 1 mm, can extend axially beyond the distal end of the outer elastomeric member 50. This additional portion of the outer layer 64 is shaped by the heat and underlying mandrel 86 for a more progressive tapering of the wall thickness of the free end 54. Furthermore, after joining the bi-layer strip 62, the process continues with the elastomeric This can include cutting through the bilayer and outer elastomeric member 50 at the free end 54. Cutting through the free end wall creates a gap similar to gap 84. The free end 54 can then be rebound using a mandrel 86. Advantageously, the cutting and rejoining process selectively weakens the elastomeric free end 54, allowing it to open more easily during passage of the implant. This aids in easier deployment and / or removal through the tip.

[0072] Advantageously, the tip and collapsed configuration allows for a large difference between the expanded and unexpanded diameters of the sheath 10. For example, the resulting final outer diameter of the sheath 10 can be as large as 19+1 French, while the expanded inner diameter is 14 French, depending on the wall thickness of the selected material. Other benefits provided by the configuration of the distal tip 28 include a more regular shape, reduced tip profile, and a smooth tip transition. The fewer layers and elastomeric free end 54 also help reduce push-through forces. The formation and expansion of the flap 30 facilitates opening the inner member 20 and opening the tip to a larger diameter than the proximal end of the inner member, e.g., 30% or more expansion than the collapsed diameter. This reduces forces and improves the reliability of removal of balloons, valves, and other implants.

[0073] Figure 12 shows that distal tip 28 transitions smoothly, with a steadily decreasing diameter, to the final diameter at the most distal edge of sheath 10. Figure 13 also shows a relatively small step down from the distal end of sheath 10 to mandrel 86. Thus, distal tip 28 can provide much greater expansion capability at the end of sheath 10 without a substantial increase in step height, taper angle, or outer diameter.

[0074] Various embodiments of the distal tip 28 include various advantages, such as elimination of sheath splits, lifted fold edges, and a thinner tip. The distal tip 28 is also better able to accommodate a larger deflated balloon shape for delivery system removal. Additionally, the distal tip 28 can provide improved tip profile, recovery capability, and circularity during recovery. According to embodiments of the distal tip 28, the smoothness of the tip transition is improved, and push forces are reduced and made more consistent.

[0075] 14, 22A, and 22B, the expandable introducer sheath 10 can include a proximal hemostatic seal assembly 88. The proximal location of the seal assembly 88 (away from the distal tip of the expandable sheath 10) reduces the size of the distal tip, smoothing the distal tip profile and allowing the flap 30 to slide more freely than if it were sealed. The proximal seal assembly 88 is particularly advantageous when used in conjunction with the flap assembly 30, as the structure of the flap assembly may allow fluid intrusion from the patient between the layers of the sheath 10.

[0076] For example, the proximal seal assembly 88 may include an intermediate member 90 extending from an inner surface 92 of the outer elastomeric member 50 to an outer surface 94 of the inner member 20. As shown schematically in FIG. 14 , the intermediate member 90 has an enlarged, open distal end 96 with an outer surface that is connected, such as by riveting or bonding, to the inner surface 92 of the outer elastomeric member 50. The intermediate member 90 tapers proximally to an annular attachment to the outer surface 94 of the inner elongate member 20.

[0077] The open distal end 96 of the proximal seal assembly 88 is not connected to the inner member 20 of the sheath 10 and can receive fluid from a leak path 98 between the members 20, 50, as shown in FIG. 17 . Thus, the leak path 98 extends between the inner surface 92 of the outer elastomeric member 50 and the outer surface 94 of the inner member 20. The leak path 98 can comprise a space between the overlapping edges 36, 38 of the first circumferential portion 24 to the proximal attachment of the middle member 90 and the inner member 20. As shown in FIG. 22A , the leak path 98 extends from the free edges of the inner member 20 and the elastomeric member 50 that are not connected to one another to proximal to the attachment of the middle member 90 and the inner member at the closed proximal end 104.

[0078] Stated another way, the unconnected or unattached length extends distal to the attachment of the intermediate member 90 to the inner member 20, to the unattached free edges of the inner member 20, outer elastomeric member 50, and any other layers or members that are not attached to one another, thereby allowing full or partial ingress of fluid along the leak path. As shown in FIG. 22B, the leak path 98 can cause a sort of balloon expansion effect on the portion of the outer elastomeric member 50 outside the body (without counteracting the force of bodily fluid pressure to offset blood pressure), thereby allowing blood pressure to reach the outer elastomeric member 50. While not entirely detrimental, balloon expansion should be suppressed or prevented to minimize the chance of leakage.

[0079] While the illustrated leak path 98 has the above characteristics, it should be noted that the seal assembly 88 may be used without a leak path, or the leak path may be different than between the two members 20, 50. Leaks can also occur in the elastomeric member 50 due to tears or pinholes forming under arterial blood pressure and are managed by the proximal seal assembly. Generally, the intermediate member 90 is shown as a tubular member having distal and proximal cylindrical portions connected by a tapered conical region in the middle. However, it should be noted that the seal assembly 88 may be constructed from a range of materials, layers, and members to achieve an end that mediates the proximal migration of leaks. For example, a disc-shaped plug extending between the inner surface 92 and the outer surface 94 may be used to block the leak path. Alternatively, multiple layers using several intermediate members in combination with a plug may be used. Alternatively, as another example, a duckbill-style valve may be used to maintain some axial mobility between the members 20, 50.

[0080] The proximal location of the proximal seal assembly 88 is generally more proximal than the distal tip 28, including the flap 30. In the illustrated embodiment, the proximal seal assembly 88 is adjacent to or slightly distal to the sheath strain relief portion 100, as shown in FIG. 14. In either case, the more proximal the location of the proximal seal assembly 88, the easier it is to manipulate the expandable introducer sheath 10, since any bulges, irregularities, or thickening caused by the seal will generally be present only at short insertion lengths ( FIG. 22A ), or completely outside the body, as shown in FIG. 22B . At the same time, however, the more distal the location of the proximal seal assembly 88, the better suited it is for placement at or just within a percutaneous opening 200 within the body, as shown in FIG. 22A . With such an arrangement, any balloon expansion (FIG. 22B) that may result from blood pressure within the leak path 98 exerting an expansive force on the resilient outer elastomeric member 50 may be reduced, minimized, or eliminated. In embodiments used for femoral access to the aortic valve, the proximal seal assembly 88 may be located 9.5 cm or more from the housing at the proximal end of the device and around the end of the strain relief portion 100.

[0081] As shown in FIG. 14 , the expandable sheath 10 can also include a fused portion 105. Specifically, the fused portion 105 is where the elastomeric member 50 is fused or attached to the inner member 20. The fused portion 105 originates at the closed proximal end 104 of the seal and extends proximally therefrom. As shown in FIG. 20 , this fusion allows the outer elastomeric member 50 to collapse into a collapsed configuration with the inner member 20, further blocking leakage between the members 20, 50. The seal assembly 88 can also include an outer jacket 102 having a tubular shape and extending along the axial portion of the sheath 10 that overlaps the middle member 90 of the seal. Preferably, the outer jacket 102 is an elastomeric material and is used to facilitate the fused portions of the inner member 20 and outer elastomeric member 50 into the collapsed configuration and to facilitate bleeding between the members at the open distal end 96. Additionally, the outer jacket 102 may include markers that indicate the depth to which the user can advance the sheath 10 to minimize or eliminate balloon expansion.

[0082] Generally, Figures 15-21 illustrate the manufacturing process for the proximal seal. In Figure 15, an inner member 20 including first and second circumferential portions 24, 26 is extruded or otherwise prepared. In Figure 16, the inner member 20 is compressed into a folded or compressed configuration by repeated folding. In Figure 17, an elastomeric outer layer 50 is sleeved over the outer surface of the inner member 20 in the folded configuration. In Figure 18, the inner member 20 is opened to an unfolded configuration by inserting a mandrel 86 into the lumen of the inner member. The outer elastomeric member 50 is also expanded (stretched) against its elastomeric bias into an expanded, unfolded configuration.

[0083] In FIG. 19, the outer elastomeric member 50 is fused to the outer surface of the inner member 20 (at least at the location of the proximal seal assembly 88). FIG. 20 shows the fused assembly (including the outer elastomeric member 50) folded into a collapsed configuration, including the addition of an elastomeric outer jacket 102. FIG. 21 shows the fused assembly in an expanded configuration. Notably, the closed proximal end 104 of the seal 88 can also be formed by fusing the middle member 90 to the inner member 20 to form the closed proximal end 104 and fusing the middle member 90 to the outer elastomeric member 50 to form the open distal end 96. In either case, the leak path 98 is at least partially sealed against proximal movement of fluid.

[0084] To prevent leakage around leak paths and / or provide additional restraint against balloon expansion of the outer elastomeric member 50, the outer jacket 102 can be configured to provide a visual indicator when the valve assembly 88 is advanced near or into the patient. For example, the outer jacket 102 can be constructed with a band of NEUSoft, which is then marked with a pen or cold laser to indicate the depth to which the sheath 10 is advanced within the patient. For example, the axial length of the outer jacket can be 1-1 / 8 inches, with a seal length of 5 / 8 inches. The distal portion of the outer jacket 102 can extend further than the distal end of the seal assembly 88, e.g., 1 / 8 inch, while an additional 3 / 8 inch is present at the proximal end of the seal assembly 88 for some safety margin.

[0085] As described above, the expandable sheath 10 can be used to deliver, remove, repair, and / or replace prosthetic devices. In one example, the sheath 10 described above can be used to deliver a prosthetic heart valve to a patient. For example, after the sheath 10 is inserted into the body and into the patient's vasculature, a heart valve attached (in a crimped or compressed state) to the distal end portion of an elongated delivery catheter is inserted into the sheath. The delivery catheter and heart valve can then be advanced through the sheath and through the patient's vasculature to the treatment site where the valve will be implanted.

[0086] Specifically, when sheath 10 is used to deliver an implant, flaps 30 at distal tip 28 are expanded to a diameter much larger than just unfolding inner elongate member 20 to facilitate deployment and removal of the balloon and implant. When an implant is passed through distal tip 28, free edges 46 of flaps 30 ride up on the outer surface (by outer elastomeric member 50) to expand the tip space. Elastomeric free ends 54 also expand to accommodate the implant. Once again free to slide at proximal, distal, and free edges 42, 44, and 46 to easily receive a deflated balloon or removed implant, distal tip 28 can be re-expanded during removal of the delivery device or removed implant using flaps 30.

[0087] Furthermore, while the expandable sheath 10 is advanced through the high pressure of the patient's arteries, blood may extend into the leak path 98 and be blocked by the seal assembly 88. As shown in Figures 22A and 22B, the sheath 10 is advanced until the outer jacket 102 abuts or extends into the inside of the patient's body. This causes the pressure of the blood or other bodily fluids to expand the outer elastomer Reduce or eliminate balloon expansion of member 50.

[0088] In addition to transcatheter heart valves, the expandable sheath 10 may be useful for other types of minimally invasive procedures, such as any procedure requiring the introduction of a device into a subject's blood vessels. For example, the expandable sheath 10 may be used to introduce other types of delivery devices for placing various types of intraluminal devices (e.g., stents, stent grafts, balloon catheters for angioplasty procedures, etc.) into many types of vascular and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary tract, intestine, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.).

[0089] Although the foregoing embodiments of the present disclosure have been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be apparent to those skilled in the art that certain changes and modifications may be made within the spirit and scope of the present disclosure. It is intended that the scope of the invention disclosed herein should not be limited by the particularly disclosed embodiments above, but should be determined only by a fair reading of the appended claims.

[0090] The present application also presents the following inventions: [Section 1] 1. An expandable sheath comprising: an elongate inner member including at least one collapsible shaft portion; an outer elastomeric member extending at least partially over the inner member and configured to exert a compressive force on the inner member to bias the at least one collapsible shaft portion into a collapsed configuration; a proximal seal including an intermediate member extending from an outer surface of the inner member to an inner surface of the outer elastomeric member, the proximal seal configured to prevent proximal migration of fluid from the distal free end of the expandable sheath to the proximal end of the expandable sheath; Expandable sheath with. [Section 2] Item 1. The expandable sheath of item 1, wherein the inner member and outer elastomeric member have unconnected lengths distal to the proximal seal. [Section 3] Item 3. The expandable sheath of item 2, wherein the unconnected length extends distally from the proximal seal to the distal free end of the expandable sheath. [Section 4] Item 4. The expandable sheath of item 2 or 3, wherein the proximal seal is configured to block a path beginning at the distal free end and extending proximally to the proximal seal. [Section 5] Item 5. The expandable sheath of any one of items 1 to 4, further comprising an outer jacket extending over the outer elastomeric member at the proximal seal. [Section 6] Item 5. The expandable sheath of any one of items 1 to 4, wherein the outer elastomeric member is fused to the inner member at the proximal seal. [Section 7] 7. The expandable sheath of any one of claims 1 to 6, wherein the outer elastomeric member is collapsible with the inner member at the proximal seal. [Section 8] 8. The expandable sheath of any one of paragraphs 1 to 7, wherein the inner member is collapsible independently from the outer elastomeric member distal to the proximal seal. [Section 9] 9. The expandable sheath of any one of paragraphs 1 to 8, wherein the elongate inner member is configured to at least partially widen the open configuration for passage of an implant. [Section 10] 10. The expandable sheath of any one of claims 1 to 9, further comprising a strain relief portion extending distally from the proximal end of the expandable sheath, the proximal seal having a proximal end adjacent the distal end of the strain relief portion. [Section 11] Item 11. The expandable sheath of any one of items 1 to 10, wherein the elongate inner member defines a central lumen, a first circumferential portion including first and second longitudinal edges, and a second circumferential portion extending between the first and second longitudinal edges. [Section 12] Item 12. The expandable sheath of item 11, wherein the elongate inner member is configured to fold at the first and second longitudinal edges into the folded configuration, and the second circumferential portion is at least partially disposed between the overlapping longitudinal edges. [Section 13] The elongate inner member further comprises a distal tip, the distal tip having a flat distal end extending from the first longitudinal edge to at least the second longitudinal edge in an open configuration of the elongate inner member. Item 13. The expandable sheath according to item 11 or 12, comprising a loop. [Section 14] 1. A method of making an expandable sheath, comprising: forming a folded configuration in the elongate inner member by forming creases along a first longitudinal edge and a second longitudinal edge of the elongate inner member such that in the folded configuration a first circumferential portion is at least partially disposed between the longitudinal edges; covering the elongated member with an elastomeric outer member; forming a proximal seal proximal to the distal free end of the expandable sheath by extending an intermediate member from an outer surface of the inner member to an inner surface of the elastomeric outer member; A method comprising: [Section 15] 15. The method of claim 14, further comprising blocking a pathway extending between the inner and outer members with the proximal seal. [Section 16] 16. The method of claim 14 or 15, further comprising fusing the elastomeric outer member to the inner member at the proximal seal. [Section 17] 17. The method of any one of paragraphs 14 to 16, further comprising extending an outer jacket over the elastomeric outer member at the proximal seal. [Section 18] 18. The method of claim 16 or 17, further comprising the step of stretching the inner member and elastomeric outer member over a mandrel to an open configuration for fusing. [Section 19] 1. A method of delivering a prosthetic device, comprising: placing an expandable sheath within the patient's vasculature up to a proximal seal on the expandable sheath; introducing a prosthetic device into a lumen of the expandable sheath; at least partially blocking proximal movement of blood between the inner and outer elastomeric members of the expandable sheath by blocking a path originating at the distal free end of the expandable sheath and extending proximally to the proximal seal; advancing the prosthetic device through the lumen of the expandable sheath such that the prosthetic device exerts a localized radially outward force on an inner surface of the inner member of the expandable sheath, causing the inner member to locally expand into an expanded configuration; at least partially collapsing the inner member at the distal tip with the outer elastomeric member after the prosthetic device has passed out of the lumen of the expandable sheath. A method comprising: [Section 20] 20. The method of claim 19, further comprising at least partially blocking the pathway with the proximal seal using an intermediate layer extending between the inner member and the outer elastomeric member. [Section 21] an elongated inner member defining a central lumen, a first circumferential portion including first and second longitudinal edges, and a second circumferential portion extending between the first and second longitudinal edges; the elongated inner member is configured to crease into a folded configuration at the first and second longitudinal edges, the second circumferential portion being at least partially disposed between the overlapping longitudinal edges; an outer elastomeric member extending around the inner elongate member and configured to bias the inner elongate member into the collapsed configuration; the elongate inner member further comprises a distal tip, the distal tip comprising a flap extending from the first longitudinal edge to at least the second longitudinal edge in an open configuration of the elongate inner member. Expandable sheath. [Section 22] Item 22. The expandable sheath of item 21, wherein the flap is configured to slide circumferentially over the outer surface of the first circumferential portion when the elongate inner member is biased into the folded configuration by the outer elastomeric member. [Section 23] Item 23. The expandable sheath of item 21 or 22, wherein the second circumferential portion has a distal edge that extends longitudinally at least to the proximal edge of the flap. [Section 24] Item 24. The expandable sheath of item 23, wherein the proximal edge of the flap extends over the distal edge of the second circumferential portion onto an outer surface of the second circumferential portion. [Section 25] 25. The expandable sheath of any one of paragraphs 21 to 24, wherein the flap comprises a longitudinal section of the second circumferential portion cut along the second longitudinal edge. [Section 26] Item 26. The expandable sheath of item 25, wherein the longitudinal section is also cut circumferentially from the distal end of the second circumferential portion. [Section 27] 27. The expandable sheath of claim 25 or 26, wherein the flaps further comprise overlapping extensions extending circumferentially from the longitudinal sections. [Section 28] 28. The expandable sheath of claim 27, wherein the overlapping extension extends proximally from the longitudinal section. [Section 29] 29. The expandable sheath of any one of paragraphs 21 to 28, wherein the distal tip further comprises an elastomeric tip extending from the distal end of the elongate inner member. [Section 30] 30. The expandable sheath of claim 29, wherein the elastomeric end has a tapered shape in the distal direction. [Section 31] 31. The expandable sheath of any one of paragraphs 21 to 30, further comprising a marker embedded within the distal tip of the elongate inner member. [Section 32] 1. A method of making an expandable sheath, comprising: forming a folded configuration in the elongate inner member by forming creases along a first longitudinal edge and a second longitudinal edge of the elongate inner member such that in the folded configuration a first circumferential portion is at least partially disposed between the longitudinal edges; forming a flap at a distal tip of the inner member such that the flap extends from a first longitudinal edge of the inner member to at least a second longitudinal edge of the inner member; covering the inner elongated member with an elastomeric outer member; A method comprising: [Section 33] 33. The method of claim 32, wherein forming the flap includes extending the flap circumferentially over an outer surface of the first circumferential portion. [Section 34] 34. The method of claim 32 or 33, wherein forming the flap includes forming a proximal edge of the flap over the distal edge and extending onto the outer surface of the second circumferential portion. [Section 35] 35. The method of claim 34, wherein the flap is at least partially formed by cutting a longitudinal section from the second circumferential portion. [Section 36] 36. The method of claim 35, wherein the flap is at least partially formed by attaching an overlapping extension to the longitudinal section. [Section 37] 37. The method of any one of paragraphs 32 to 36, further comprising attaching an elastomeric end to a distal end of the inner elongate member. [Section 38] 38. The method of claim 37, further comprising forming a tapered shape at the elastomeric end. [Section 39] 1. A method of delivering a prosthetic device, comprising: placing an expandable sheath within the patient's vasculature; introducing a prosthetic device into a lumen of the expandable sheath; advancing the prosthetic device through the lumen of the expandable sheath such that the prosthetic device exerts a radially outward force on an interior surface of the inner member of the expandable sheath, locally expanding the inner member to an expanded configuration; advancing the prosthetic device further through the lumen to the distal tip of the expandable sheath, causing a free end of a flap at the distal tip to slide circumferentially over an outer surface of a first circumferential portion of the expandable sheath in response to radial pressure exerted by the passage of the prosthetic device, thereby locally expanding the lumen; at least partially collapsing the inner member at the distal tip after the prosthetic device has passed out of the lumen of the expandable sheath. A method comprising: [Section 40] 40. The method of claim 39, further comprising the step of advancing the prosthetic device through an elastomeric end extending around the distal end of the lumen, expanding the elastomeric end and at least partially collapsing the elastomeric end after the prosthetic device has passed therethrough. [Section 41] 41. The method of claim 39 or 40, wherein the step of at least partially folding the inner member includes sliding the free end of the flap at the distal tip circumferentially over the outer surface of the first circumferential portion to locally reduce the lumen. [Explanation of symbols]

[0091] 10 Expandable sheath, sheath, expandable introductory sheath 20 Elongated inner member, inner member, inner elongated member, member 22 Folded part or crease, crease, crease or fold line, fold line 24 first circumferential portion, sheath circumferential portion, circumferential portion 26 second circumferential portion, sheath circumferential portion, circumferential portion 28 distal tip, distal end 30 Flap, overlapping flap, flap assembly, cutting tab 36 First longitudinal edge, overlapping edge, second longitudinal edge 38 edge, second longitudinal edge, longitudinal edge, overlapping edge 40 Longitudinal Edge 42 Distal margin 44 Proximal margin 46 Free Edge 48 Connected Edges 50 outer elastomeric member, elastomeric outer elastomeric member, member, outer elastic member, elastomeric member, elastomeric outer layer 52 Radiopaque marker band, marker band 54 Elastomer free end, free end 58 Distal margin 60 Extended overlap, extended overlap, flap extension 62 Double-Layer Strip 64 layers, outer layer 66 layers, inner layer 68 Rectangular body 70 Small Tabs 72 Large Tab 74 Proximal rounded corner 80 Double-Layer Tab 81 Axial extending edge 82 Free Edge 83 Distal margin 84 Gap 86 Mandrel 88 Proximal Hemostatic Seal Assembly, Seal Assembly, Seal, Valve Assembly, Proximal Seal Assembly 90 Intermediate parts 92 Inside 94 External surface, external surface 96 Open Distal End 98 Leakage path 100 strain relief part, strain relief part 102 outer jacket 104 Closed proximal end 105 Fusion part 110 Delivery device 114 Steerable guide catheter, guide catheter 116 Balloon Catheter 120 Handle part 122 Long, thin guide tube or shaft 200 Percutaneous opening

Claims

1. An expandable sheath comprising an elongated inner member that is movable between a non-expanded form and an expanded form, The inner member includes a first circumferential portion including a first longitudinal edge and a second longitudinal edge, and in the non-expanded form, the first longitudinal edge and the second longitudinal edge overlap, and as the inner member moves toward the expanded form, the circumferential overlap of the first longitudinal edge and the second longitudinal edge decreases. The inner member includes a distal tip, the distal tip includes a flap, and the flap is A free edge is formed by an axial slit extending axially from the distal end of the inner member towards the proximal end along the length of the inner member, The circumferential proximal edge formed by a circumferential slit extending around a portion of the inner member and Equipped with, An expandable sheath, wherein the distal tip is movable between a non-expanded state and an expanded state, and in the non-expanded state, the flap extends circumferentially around the adjacent portion of the inner member and overlaps with the adjacent portion of the inner member, and when the distal tip moves toward the expanded state, the flap moves toward a state with less overlap.

2. The expandable sheath according to claim 1, wherein the proximal circumferential edge of the flap is positioned along the inner member between the proximal end of the free edge of the flap and the distal end of the first circumferential portion of the inner member.

3. The expandable sheath according to claim 1, wherein the first end of the circumferential proximal edge of the flap is aligned with the proximal end of the free edge of the flap.

4. The expandable sheath according to claim 1, wherein the circumferential slit extends from the proximal end of the axial slit.

5. The expandable sheath according to claim 1, wherein the circumferential slit extends over a shorter area than the entire circumference of the inner member.

6. The expandable sheath according to claim 1, wherein a connected edge is formed between the first end of the circumferential slit and the second end of the circumferential slit, such that the flap is attached to the first circumferential portion of the inner member.

7. The expandable sheath according to claim 1, wherein the distal tip has a diameter smaller than the diameter of the inner member, and the distal tip defines a tapered shape extending from the first circumferential portion of the inner member to the distal end of the inner member such that, in the non-expanded configuration, the proximal end of the distal tip has a diameter larger than the diameter of the distal end of the distal tip.

8. The expandable sheath according to claim 1, wherein the flap is configured to slide circumferentially on the base portion of the flap when the distal tip moves between the non-expanded state and the expanded state.

9. The expandable sheath according to claim 1, wherein the axial slit of the flap extends in a direction substantially perpendicular to the circumferential slit of the flap.

10. The expandable sheath according to claim 1, wherein the flap further includes an overlapping extension extending circumferentially from the free edge of the flap.

11. The expandable sheath according to claim 1, wherein the distal tip further comprises an elastomer end extending from the distal end of the elongated inner member.

12. The expandable sheath according to claim 11, wherein the elastomer end has a tapered shape in the distal direction.

13. The expandable sheath according to claim 11, wherein the elastomer end restricts the free expansion of the flap relative to the rest of the inner member.

14. The expandable sheath according to claim 11, wherein the elastomer end is configured to expand and / or tear as the distal tip moves from the non-expanded state to the expanded state.

15. The expandable sheath according to claim 1, further comprising a marker embedded in the inner member near the distal tip.

16. The expandable sheath according to claim 15, wherein the marker is located near the free edge and / or the circumferential proximal edge of the flap.

17. The expandable sheath according to claim 15, wherein the marker is located near at least one of the proximal end of the free edge of the flap or the first end of the circumferential proximal edge of the flap.

18. The expandable sheath according to claim 1, further comprising an outer elastomer member that extends to at least partially cover the inner member and is configured to exert a compressive force on the inner member such that it biases the inner member toward the non-expanded form.

19. The expandable sheath according to claim 1, further comprising a strain relief portion extending distally from the proximal end of the expandable sheath, wherein the strain relief portion has a durometer higher than that of the elongated inner member.

20. The expandable sheath according to claim 1, wherein the inner member is configured to expand at least partially toward the expanded form in order to allow a graft to pass through the central lumen of the expandable sheath.

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