Devices and methods for stabilizing sheath systems

Abstract

Disclosed herein are systems and methods for setting a length of sheath used in an introducer sheath system to deploy a medical device. The capacity to adjust the length of the sheath facilitates reducing a portion of the sheath that remains outside of the patient during medical procedures, wherein a distance between an incision site and a treatment site is less than an initial length of the sheath.

Description

DEVICES AND METHODS FOR STABILIZING SHEATH SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 684,247, filed August 16, 2025, which is incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The present application is directed to a sheaths and introducers for use with catheterbased technologies for repairing and / or replacing heart valves, as well as for delivering a medical device, such as a prosthetic, valve to a heart via the patient’ s vasculature.BACKGROUND

[0003] Endovascular delivery catheter assemblies are used to implant prosthetic devices, such as prosthetic valves, at locations inside the body that are not readily 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] Percutaneous interventional medical procedures utilize the large blood vessels of the body to reach target destinations rather than surgically opening the target site. There are many types of disease states that can be treated via percutaneous interventional methods, including (but not limited to) coronary blockages, valve replacements (TAVR) and brain aneurysms. These percutaneous interventional methods use wires, catheters, balloons, electrodes and other thin devices to travel down the length of the blood vessels from the access site to the target site. The devices have a proximal end which the clinician controls outside of the body and a distal end inside the body.

[0005] Percutaneous interventional procedures offer several advantages over open surgical techniques. First, they require smaller incision sites which reduces scarring and bleeding as well as infection risk. Procedures are also less traumatic to the tissue, so recovery times are reduced. Finally, interventional procedures can usually be performed faster and with fewer clinicians, lowering costs. In some cases, the need for anesthesia is also eliminated, further speeding up the recovery process and reducing risk.

[0006] A single procedure typically uses several different guidewires, catheters, and balloons to achieve the desired effect. One at a time, each tool is inserted and then removedfrom the access site sequentially. For example, a guidewire is used to track the correct location within the body. Next a balloon (carried on a balloon catheter) may be used to dilate a section of narrowed blood vessel. Last, an implant (carried on yet another catheter) may be delivered to the target site.

[0007] Introducer sheaths serve as conduits for the catheters. They are inserted into the access site to protect the vessel, which could otherwise be damaged by the introduction of multiple catheters with rough edges. Introducer sheaths also seal the blood vessel to reduce bleeding from the access site. An introducer sheath generally has a proximally positioned housing and an elongated sleeve that is inserted into the vasculature. The proximal housing contains one or more sealing valves that allow a delivery apparatus to be placed in fluid communication with the vasculature with minimal blood loss. Once the introducer sheath is positioned within the vasculature, the catheters, and ultimately the delivery apparatus carrying the prosthetic device, are sequentially advanced through the sheath. Expandable introducer sheaths, formed of highly elastomeric materials, allow the passing prosthetic device to dilate the vessel.

[0008] The femoral artery is often chosen as the vascular incision site. The femoral approach involves creating an incision site in the femoral artery at the groin, then inserting the introducer sheath, and ultimately routing the delivery apparatus though the introducer sheath and to the target site. This method offers a straightforward path to major vessels, facilitating diagnostic imaging and interventions. The femoral approach is often preferred over alternative approaches for several reasons, including the large diameter of the artery, the less tortuous path to the heart and major vessels, and the relative ease and safety of access. As such, introducer sheaths are often designed to be used with a femoral approach.

[0009] However, alternative vascular incision sites, which are closer to the heart, may be used according to physician preference and / or when complications preclude the femoral approach. For example, navigating a catheter over the greater distance from the femoral incision site to the heart can be difficult with vascular complications like atherosclerosis, increased tortuosity, and reduced vascular elasticity. Introducer sheaths that are designed for the femoral approach are not well suited for use in these alternative vascular incision sites. Accordingly, there is a need for systems and methods that facilitate the use of introducer sheath systems at alternative vascular incision sites.SUMMARY OF THE INVENTION

[0010] In one of its basic configurations, the present disclosure provides devices, systems, and methods for setting a length of the sheath so as to reduce a portion of the sheath that remains outside the patient’ s body during the procedure. This capacity is particularly advantageous where the distance between the incision site and the treatment site is less than an initial length of the sheath. This basic configuration can preferably be provided with any one or more of the features described elsewhere herein, in particular with those of the examples described hereafter. However, it should be understood that the basic configuration can preferably also be provided with any one or more of the features shown in the figures and / or described in conjunction with the figures, either in addition to or alternatively to the examples described hereafter.

[0011] An example method of setting a sheath length according to the present disclosure includes handling a sheath, where the sheath extends an initial sheath length between an initial distal end and an initial proximal end and defines a central lumen extending longitudinally therethrough. The initial proximal end of the sheath is coupled to an initial sheath hub. The method also includes cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location, where cutting the sheath divides the sheath into a first section that has a first section length that extends from the initial distal end to the second proximal end and a second section that extends from the second distal end to the initial proximal end. The method also includes coupling the second proximal end of the first section with a second sheath hub.

[0012] An example method of delivering a medical device through a sheath according to the present disclosure includes handling a radially expandable sheath that includes a continuous inner layer that extends an initial sheath length between an initial distal end and an initial proximal end and defines a central lumen extending longitudinally therethrough. The initial proximal end of the sheath is coupled to an initial sheath hub and the inner layer has at least one folded portion extending along a length of the inner layer. The method also includes cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location such that the sheath is divided into a first section that extends from the initial distal end to the second proximal end and a second section that extends from the second distal end to the initial proximal end. The method also includes coupling the second proximal endof the first section with a second sheath hub, inserting the sheath into an incision site of a patient, and advancing a medical device through the central lumen of the sheath. This causes the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to an outwardly directed radial force of the medical device exerted against the inner layer and locally contract at least partially back to the unexpanded configuration as the medical device passes through the central lumen. The method also includes advancing the medical device beyond a distal opening of the sheath to the treatment site.

[0013] An example sheath coupling system according to the present disclosure includes a sheath hub that includes a hub body that has a proximal end and a distal end and defines a lumen extending longitudinally therethrough. The sheath coupling system also includes an initial hub cap coupled to the distal end of the sheath hub. The initial hub cap has an initial hub cap proximal end and an initial hub cap distal end and defines an initial hub cap lumen extending longitudinally therethrough. The sheath coupling system also includes a hub coupler coupled to the initial hub cap. The hub coupler includes a hub coupler body that has a hub coupler proximal end and a hub coupler distal end and defines a hub coupler lumen extending longitudinally therethrough. The sheath coupling system also includes a secondary hub cap disposed distal to the initial hub cap and coupled to the hub coupler. The secondary hub cap has a secondary hub cap proximal end and a secondary hub cap distal end and defines a secondary hub cap lumen extending longitudinally therethrough. The sheath coupling system also includes a sheath that includes a distal end and a proximal end and defines a central lumen extending longitudinally therethrough. The proximal end of the sheath is positioned between the distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub.

[0014] Another example method of setting a sheath length according to the present disclosure includes handling a sheath, where the sheath extends an initial sheath length between an initial distal end and an initial proximal end and defines a central lumen extending therethrough. The initial proximal end of the sheath is coupled to an initial sheath hub cap, and the initial sheath hub cap is coupled to a sheath hub. The method also includes cutting the sheath at a first cut location between the initial distal end and the initial proximal end so as to form a second distal end and a second proximal end on either side of the cut location. The method also includes cutting the sheath at a second cut location between the first cut location and the initial distal end so as to form a third distal end and a third proximalend on either side of the second cut location. Cutting the sheath at the first cut location and second cut location divides the sheath into a first section that has a first section length extending from the initial distal end to the third proximal end, a second section that has a second section length extending from the third distal end to the second proximal end, and a third section that has a third section length extending from the second distal end to the initial proximal end. The method also includes coupling a proximal end of a hub coupler to a distal end of the sheath hub; and coupling a proximal end of a secondary hub cap to a distal end of the hub coupler. The sheath is positioned between a distal end of the secondary huh cap and the distal end of the hub coupler such that coupling the secondary sheath hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub.

[0015] Another example method of delivering a medical device according to the present disclosure includes handling a radially expandable sheath including a continuous inner layer extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough. The initial proximal end of the sheath is coupled to an initial sheath hub cap and the initial sheath hub cap is coupled to a sheath hub. The inner layer has at least one folded portion extending along a length of the inner layer. The method also includes cutting the sheath at a first cut location between the initial distal end and the initial proximal end so as to form a second distal end and a second proximal end on either side of the cut location. The method also includes cutting the sheath at a second cut location between the first cut location and the initial distal end so as to form a third distal end and a third proximal end on either side of the second cut location. Cutting the sheath at the first cut location and second cut location divides the sheath into a first section that has a first section length extending from the initial distal end to the third proximal end, a second section that has a second section length extending from the third distal end to the second proximal end, and a third section that has a third section length extending from the second distal end to the initial proximal end. The method also includes coupling a proximal end of a hub coupler to a distal end of the hub. The method also includes coupling a proximal end of a secondary hub cap to a distal end of the hub coupler, where the sheath is positioned between a distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary sheath hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub. The method also includes inserting the sheath into an incision site of a patient. The method also includes advancing a medical device through the central lumen of the sheath causing the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to anoutwardly directed radial force of the medical device exerted against the inner layer and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen. The method also includes advancing the medical device beyond a distal opening of the sheath to the treatment site.

[0016] An example introducer sheath system according to the present disclosure includes a sheath extending a length between a distal end and a proximal end and defining a central lumen extending longitudinally therethrough. The introducer sheath system also includes a locking hub including a hub body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end. The introducer sheath system also includes an introducer coupled to the introducer locking hub and received within the sheath. The introducer extends beyond the distal end of the hub body and includes a proximal piece and a separate distal piece. The proximal piece of the introducer is coupled to the introducer locking hub and defines a central lumen extending therethrough. The distal end of the sheath is provided between the proximal piece and the distal piece of the introducer such that the distal end of the sheath does not extend radially beyond an outer diameter of the distal piece of the introducer.

[0017] Another example method of setting a sheath length according to the present disclosure includes handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough. The initial proximal end of the sheath is coupled to a sheath hub. The method also includes cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location. Cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that has a second section length extending from the second distal end to the initial proximal end. The method also includes inserting an introducer into the sheath hub and advancing the introducer through the central lumen of the sheath. The method also includes moving a distal piece of the introducer from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece. The distal piece of the introducer includes a proximal end and a distal end. The proximal end of the distal piece of the introducer includes a tapered region that tapers radially inward toward the distal end. The method also includes and enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer.

[0018] Another example method of delivering a medical device according to the present disclosure includes handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough. The initial proximal end of the sheath is coupled to a sheath hub. The method also includes cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location. Cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that has a second section length extending from the second distal end to the initial proximal end. The method also includes inserting an introducer into the sheath hub and advancing the introducer through the central lumen of the sheath. The method also includes moving a distal piece of the introducer from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece. The distal piece of the introducer includes a proximal end and a distal end. The proximal end of the distal piece of the introducer includes a tapered region that tapers radially inward toward the distal end. The method also includes enclosing the second distal end of the sheath within the tapered region of the distal piece of the introducer. The method also includes pushing the coupled sheath and introducer at least partially into the vasculature of a patient. The method also includes withdrawing the introducer from the central lumen of the sheath. The method also includes pushing a medical device through the central lumen of the sheath toward a treatment site. The method also includes and delivering the medical device to the treatment site via the central lumen of the sheath.

[0019] Another example introducer sheath system according to the present disclosure includes a sheath hub including a proximal end and distal end and defining a lumen extending longitudinally therethrough. The introducer sheath system includes a sheath coupled to and extending distally from the sheath hub. The sheath extends a sheath length between a distal end and a proximal end and defines a central lumen extending longitudinally therethrough. The introducer sheath system includes a suture hub at least partially surrounding the sheath. The suture hub has a suture hub body with a proximal surface and a distal surface and defining a central lumen extending longitudinally therethrough. The suture hub further includes one or more openings sized to house a suture for securing the suture hub to a patient. The sheath is movable between a slidable configuration, in which the sheath is axially slidable within the central lumen of the suture hub, and a coupled configuration, in which the sheath is fixedly coupled to a locking mechanism on the suture hub to resist axial movementof the sheath. An effective sheath length corresponding to a length of the sheath that is received within the patient is defined as the length of the sheath between distal surface of the suture hub and the distal end of the sheath.

[0020] Another example method of delivering a medical device through a sheath according to the present disclosure includes: inserting a sheath into a patient at an incision site; pushing a distal end of the sheath to a location within the patient's vasculature adjacent a treatment site; sliding a suture hub along an outer surface of the sheath; coupling the suture hub to a surface of the patient's skin adjacent to the incision site; and fixedly coupling the suture hub and the sheath so as to resist axial movement of the sheath. An effective sheath length is defined as the length of the sheath that extends between a distal surface of the suture hub and the distal end of the sheath and corresponds to a length of the sheath that is received within a patient. The method of delivering a medical device through a sheath also includes pushing a medical device through the sheath toward the treatment site.

[0021] Various aspects of the examples described herein can be combined based on desired sheath system characteristics.BRIEF DESCRIPTION OF DRAWINGS

[0022] The device is explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The drawings are not necessarily drawn to scale.

[0023] FIG. 1 is an elevation view of an expandable sheath along with an endovascular delivery apparatus for implanting a medical device.

[0024] FIG. 2 is an elevation view of an expandable sheath including an introducer locking hub, a sheath locking sleeve, and an introducer.

[0025] FIG. 3 is an elevation view of the expandable sheath of FIG. 2 along with an endovascular delivery apparatus for implanting a medical device.

[0026] FIG. 4 is an elevation view of an expandable sheath a sheath hub, an introducer locking huh, and a sheath locking sleeve of FIG. 2.

[0027] FIG. 5A is a cross-sectional view of the sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2.

[0028] FIG. 5B is a cross-sectional view of the introducer cap, the sheath hub, the introducer locking hub, the sheath locking sleeve of FIG. 2.

[0029] FIG. 6 is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2.

[0030] FIG. 7 is a distal end view of the sheath locking sleeve of FIG. 2 and the proximal fluid seal of FIGS 5A-B.

[0031] FIG. 8A is a first elevation view of the introducer locking hub of FIG. 2 coupled to an introducer.

[0032] FIG. 8B is a second (rotated) elevation view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0033] FIG. 8C is a distal end view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0034] FIG. 8D is a partial side view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0035] FIG. 8E is a partial perspective view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0036] FIG. 8F is a partial perspective view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0037] FIG. 9A is a distal end view of the introducer locking hub of FIG. 2.

[0038] FIG. 9B is a first elevation view of the introducer locking hub of FIG. 2.

[0039] FIG. 9C is a proximal end view of the introducer locking hub of FIG. 2.

[0040] FIG. 9D is a first perspective view of the introducer locking hub of FIG. 2.

[0041] FIG. 9E is a second elevation view of the introducer locking hub of FIG. 2.

[0042] FIG. 9F is a second perspective view of the introducer locking hub of FIG. 2.

[0043] FIG. 10A is a distal end view of the sheath locking sleeve of FIG. 2.

[0044] FIG. 10B is a first elevation view of the sheath locking sleeve of FIG. 2.

[0045] FIG. 10C is a proximal end view of the sheath locking sleeve of FIG. 2.

[0046] FIG. 10D is a first perspective view of the sheath locking sleeve of FIG. 2.

[0047] FIG. 10E is a second elevation view of the sheath locking sleeve of FIG. 2.

[0048] FIG. 10F is a second perspective view of the sheath locking sleeve of FIG. 2.

[0049] FIG. 11 is a side elevation cross-sectional view of a portion of the expandable sheath of FIGS. 1 and 2.

[0050] FIG. 12 is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2.

[0051] FIG. 13A is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2 with the outer layer removed for purposes of illustration.

[0052] FIG. 13B is a magnified view of a portion of the braided layer of the sheath of FIGS. 1 and 2.

[0053] FIG. 14 is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2 illustrating expansion of the sheath as a medical device is advanced through the sheath.

[0054] FIG. 15 is a side view of the expandable sheath of FIGS. 1 and 2.

[0055] FIG. 16 is a magnified cross-sectional section view of the sheath of FIG. 15 along section line 16-16.

[0056] FIG. 17 is cross-sectional view of the unexpanded sheath of FIG. 16 along section line 17-17.

[0057] FIG. 18 is cross-sectional view of the unexpanded sheath of FIG. 15 along section line 18-18.

[0058] FIG. 19 is cross-sectional view of the unexpanded sheath of FIG. 15 along section line 19-19.

[0059] FIG. 20 is cross-sectional view of the expanded sheath of FIG. 15 along section line 19-19.

[0060] FIG. 21 is a side view of the expandable sheath of FIGS. 1 and 2.

[0061] FIG. 22 is a cross-sectional view of the unexpanded sheath of FIG. 21 along section line 22-22.

[0062] FIG. 23 is a cross-sectional view of the expanded sheath of FIG. 21 along section line 22-22.

[0063] FIG. 24 shows various percutaneous vascular access approaches.

[0064] FIG. 25 shows side views of an introducer sheath system according to another example, where a length of the sheath is adjusted.

[0065] FIG. 26 is a perspective view of a sheath coupling system according to one example, the introducer sheath system including a hub coupler for coupling an initial hub cap of the introducer sheath system with a secondary hub cap of the introducer sheath, thereby coupling the sheath with the sheath hub.

[0066] FIG. 27 is an enlarged cross-sectional side view of the sheath coupling system of FIG. 26.

[0067] FIG. 28 is a perspective view of the hub coupler of FIG. 26.

[0068] FIG. 29A shows side views of an introducer sheath system according to another example, where a length of the sheath is adjusted.

[0069] FIG. 29B shows side views of an introducer sheath system of FIG. 29A, including a hub coupler for coupling the sheath to a sheath hub.

[0070] FIG. 30 shows side views of an introducer sheath system according to another example, where a length of the sheath is adjusted and an introducer is inserted into a sheath hub.

[0071] FIG. 31 is a cross-sectional side view of the introducer of FIG. 30.

[0072] FIG. 32 is a side view of the introducer sheath system of FIG. 30, where the introducer is inserted into the sheath after the length of the sheath has been adjusted.

[0073] FIG. 33 is a side view of an introducer sheath system according to another example, the introducer sheath system including a suture hub for coupling a sheath to a patient.

[0074] FIG. 34 is a side view of the example suture hub of FIG. 33.

[0075] FIG. 35 is a side view of an example suture hub according to another example.

[0076] FIG. 36 is a side view of a loader assembly used for loading a balloon catheter and medical device into the introducer sheath system of FIG. 33.

[0077] FIGS. 37 and 38 are side views illustrating the insertion of a delivery system into a loader assembly of FIG. 36.DETAILED DESCRIPTION

[0078] The following description of certain examples of the inventive concepts should not be used to limit the scope of the claims. Other examples, features, aspects, implementations, and advantages will become apparent to those skilled in the art from the following description. As will be realized, the device and / or methods are capable of other different and obvious aspects, all without departing from the spirit of the inventive concepts. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.

[0079] For purposes of this description, certain aspects, advantages, and novel features of the aspects of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed examples, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.

[0080] Features, integers, characteristics, compounds, chemical moieties, or groups described in conjunction with a particular aspect or example of the present disclosure are to be understood to be applicable to any other aspect or example described herein unlessincompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The present disclosure is not restricted to the details of any foregoing examples. The present disclosure extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0081] It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is 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. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0082] As used in the 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 “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another aspect 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 aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0083] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0084] The terms “proximal” and “distal” as used herein refer to regions of a sheath, catheter, or delivery assembly. “Proximal” means that region closest to handle of the device, while “distal” means that region farthest away from the handle of the device.

[0085] “Axially” or “axial” as used herein refers to a direction along the longitudinal axis of the sheath.

[0086] Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0087] Disclosed examples of an expandable sheath can minimize trauma to the vessel by allowing for temporary expansion of a portion of the introducer sheath to accommodate the delivery apparatus, followed by a return to the original diameter once the device passes through. Disclosed examples of the introducer sheath prevent the introducer / dilator from separating from the sheath during insertion by locking of the proximal hub of the introducer / dilator to the proximal hub of the sheath. Fixing the introducer / dilator and the sheath prevents the introducer / dilator from moving backward during insertion, thereby maintaining a snug fit and smooth transition between the introducer / dilator and the distal end of the sheath. Furthermore, present examples can reduce the length of time a procedure takes, as well as reduce the risk of a longitudinal or radial vessel tear, or plaque dislodgement because only one sheath is required, rather than several different sizes of sheaths. Examples of the present expandable sheath can avoid the need for multiple insertions for the dilation of the vessel.

[0088] Disclosed herein are elongate introducer sheaths that are particularly suitable for delivery of implants in the form of implantable heart valves, such as balloon-expandable implantable heart valves. Balloon-expandable implantable heart valves are well-known and will not be described in detail here. An example of such an implantable heart valve is described in U.S. Patent No. 5,411,552, and also in U.S. Patent No. 9,393,110, both of which are hereby incorporated by reference. The expandable introducer sheaths disclosed herein may also be used to deliver other types of implantable medical device, such as self-expanding and mechanically expanding implantable heart valves, stents or filters. Beyond transcatheter heart valves, the introducer sheath system can be useful for other types of minimally invasive surgery, such as any surgery requiring introduction of an apparatus into a subject’s vessel. For example, the introducer sheath system can be used to introduce other types of delivery apparatus for placing various types of intraluminal devices (for example, stents, stented grafts, balloon catheters for angioplasty procedures, etc.) into many types of vascular and non-vascular body lumens (for example, veins, arteries, esophagus, ducts of the biliary tree, intestine, urethra, fallopian tube, other endocrine or exocrine ducts, etc.). The term“implantable” as used herein is broadly defined to mean anything - prosthetic or not - that is delivered to a site within a body. A diagnostic device, for example, may be an implantable.

[0089] Example expandable introducer sheaths are disclosed, for example, in U.S. Patent No. 8,690,936, entitled “Expandable Sheath for Introducing an Endovascular Delivery Device into a Body,” U.S. Patent No. 8,790,387, entitled “Expandable Sheath for Introducing an Endovascular Delivery Device into a Body,” U.S. Patent No. 10,639,152, entitled “Expandable Sheath and Methods of Using the Same,” U.S. Patent No. 10,792,471, entitled “Expandable Sheath,” U.S. Patent No. Application No. 16 / 407,057, entitled “Expandable Sheath with Elastomeric Cross Sectional Portions,” U.S. Patent No. 10,327,896, entitled “Expandable Sheath with Elastomeric Cross Sectional Portions,” U.S. Patent No. 11,273,062, entitled “Expandable Sheath,” Application No. PCT / US2021 / 019514, entitled “Expandable sheath for introducing an endovascular delivery device in to a body,” Application No. PCT / US2021 / 031227, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” Application No. PCT / US2021 / 031275, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” U.S. Application No. 17 / 113,268, entitled “Expandable Sheath and Method of Using the Same,” Application No. PCT / US2021 / 058247, entitled “Self-Expanding, Two Component Sheath,” Application No. PCT / US2022 / 012785, entitled “Expandable Sheath,” U.S. Patent No. 11,051,939, entitled “Active Introducer Sheath System,” Application No. PCT / US2022 / 012684, entitled “Introducer with Sheath Tip Expander,” U.S. Application No. 17 / 078,556, entitled “Advanced Sheath Patterns,” Application No. PCT / US2021 / 025038, entitled “Low temperature hydrophilic adhesive for use in expandable sheath for introducing an endovascular delivery device into a body,” Application No. PCT / US2021 / 050006, entitled “Expandable Sheath Including Reversable Bayonet Locking Hub,” U.S. Provisional Application No. 63 / 280,251, entitled “Expandable Sheath Gasket to Provide Hemostasis,” U.S. Provisional Application No. 63 / 530,144, entitled “Introducer / Dilator with Folded Balloon,” and U.S. Provisional Application No. 63 / 502,907, entitled “Lead Screw Driven Sheath Dilator,” the disclosures of which are herein incorporated by reference.

[0090] FIG. 1 illustrates an exemplary sheath 8 in use with a representative delivery apparatus 10, for delivering a medical device 12, or other type of implantable (for example, tissue heart valve), to a patient. The delivery apparatus 10 can include a steerable guide catheter 14 (also referred to as a flex catheter) and a balloon catheter 16 extending through the guide catheter 14, and a nose catheter 15 extending through the balloon catheter 16. The guide catheter 14, balloon catheter 16, and nose catheter 15 in the illustrated example areadapted to slide longitudinally relative to each other to facilitate delivery and positioning of the medical device 12 at an implantation site in a patient’s body as described in detail herein. It is contemplated that the sheath 8 can be used with any type of elongated delivery apparatus used for implanting balloon-expandable prosthetic valves, self-expanding prosthetic valves, and other prosthetic devices.

[0091] As described in more detail herein, in general, the sheath 8 comprises an elongate expandable tube that, in use, is inserted into a vessel (for example, transfemoral vessel, femoral artery, iliac artery) by passing through the skin of patient, such that the distal end of the sheath 8 is inserted into the vessel. Sheath 8 includes a hemostasis valve and / or sealing features at the proximal end of the sheath, for example, in the sheath hub 20, that provide hemostasis and prevents blood leakage from the patient through the sheath 8. The sheath 8, including an introducer 6 (also referred to herein as a dilator), is advanced into the patient’s vasculature. Once positioned the introducer 6 is removed and the delivery apparatus 10 is inserted into / through the sheath 8, and the prosthetic device (medical device 12) then be delivered and implanted within patient.

[0092] FIGS. 2 and 3, the introducer device / sheath assembly includes a sheath hub 20 at a proximal end of the device and an expandable sheath 8 extending distally from the sheath hub 20. The sheath 8 is coupled to the sheath hub 20 which in turn is removably coupled to a sheath locking system 18. The sheath locking system 18 allows the introducer 6, or other device desired to be removably couped (axially and rotatably) to the sheath 8.

[0093] As illustrated in FIGS. 2-6, the sheath hub 20 can function as a handle for the device. Sheath hub 20 also provides a housing for necessary seal assemblies and an access point for a secondary lumen (for example, fluid lumen) in fluid communication with the central lumen of the sheath hub 20. The seal assembly 24, as described herein and as shown in FIGS. 5 A and 5B, is included in the sheath hub 20. The seal assembly 24 includes a proximal seal 24a, an intermediate seal 24b, and a distal seal 24c. When assembled, the introducer 6 passes through the seal assembly and extends distal of the sheath 8. The proximal seal 24a, the intermediate seal 24b, and the distal seal 24c are each formed to prevent unwanted fluid from advancing in the proximal direction through the sheath hub 20 and proximal of the seal assembly 24. They are each openable and closable to provide pressure variation to affect the desired fluid flow from a physician or technician.

[0094] The distal end of the sheath hub 20 includes threads 21 for coupling to a threaded sheath hub cap 22. The sheath 8 is provided between the sheath hub 20 and the sheath hub cap 22 such that coupling the sheath hub cap 22 to the sheath hub 20 fixes the sheath 8 to thesheath hub 20. The sheath hub cap 22 is a cylindrical cap having a cap body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end. The sheath hub cap 22 has a larger diameter at its proximal end than at its distal end.

[0095] The sheath hub 20 further has receiving slots 48 for coupling the sheath locking system 18, particularly the locking sleeve 28, to the sheath hub 20. The receiving slots 48 are openings which extend around a portion of the diameter of the sheath hub 20 and are sized and configured to accept the interference diameters 66 of the locking sleeve 28. Coupling between the receiving slots 48 and the interference diameters 66 axially and rotationally fixes the locking sleeve 28 and the sheath hub 20 relative to each other.

[0096] FIG. 2 illustrates the sheath 8 of FIG. 1 including a sheath locking system 18 which prevents axial and rotational translation of the introducer 6 with respect to the sheath 8. Example locking systems are disclosed in PCT / US2021 / 050006, entitled “Expandable Sheath Including Reverse Bayonet Locking Hub,” the disclosure of which is incorporated herein by reference. It is contemplated that the locking system disclosed herein can also be used to couple the sheath 8 / sheath hub 20 with other delivery apparatus components, catheters, dilators, etc. including the same mating features.

[0097] The sheath locking system 18 keeps the introducer 6 fixed with respect to the sheath 8 during insertion without requiring a physician or technician to hold the introducer 6 and the sheath 8 in place at the distal end. As illustrated in FIGS. 8A-8B, the sheath locking system 18 includes a locking sleeve 28 and an introducer locking hub 30 (including corresponding introducer 6). The locking sleeve 28 is coupled to the sheath 8 via the sheath hub 20. The locking sleeve 28 engages the introducer locking hub 30 and is moveable between a locked and unlocked position, thereby fixing the position of the introducer 6 and the sheath 8 and preventing movement therebetween, particularly during insertion into the patient. As will be described in more detail herein, the sheath locking system 18 keeps the introducer 6 from separating from the sheath 8 and prevents gaps from forming that can cause patient abrasions and unintended fluid flow between the introducer 6 and the sheath 8 during insertion.

[0098] FIGS. 2, 5A-5B and 6, and illustrate the locking sleeve 28 coupled to the introducer locking hub 30 and the sheath hub 20. As will be described in more detail herein, the locking sleeve 28 includes a guide 31 that engages a locking channel 38 provided on the introducer locking hub 30. The guide 31 moves within the locking channel 38 between an unlocked position, where the locking sleeve 28 is rotationally and axially movable with respect to theintroducer locking hub 30, and a locked position (FIG. 2), where the locking sleeve 28 is axially fixed with respect to the introducer locking hub 30.

[0099] The locking sleeve 28 is illustrated, for example, in FIGS. 10A-10F. The locking sleeve 28 includes an elongated sleeve body 29 with a central lumen 56 extending longitudinally between the proximal end 58 and distal end 60 of the sleeve body 29. As provided in FIG. 6, the central lumen 56 defines a generally cylindrical inner surface 62 of the sheath locking sleeve 28. The central lumen 56 has a diameter of at least 0.3 inches. In some examples, the diameter ranges between 0.3 inches and 0.6 inches. Preferably, the diameter is about 0.40 inches. The distal end 60 of the sleeve body 29 also has a frustoconical outer surface 64 that tapers about the distal end 60 to help with positioning the locking sleeve 28 within the sheath hub 20 and abutting the seal assembly 24 (FIGS. 5B and 5B). The locking sleeve 28 also has a plurality of interference diameters 66 that extend radially from the outer surface of the sleeve body 29 around (all or a portion of) the circumference of the locking sleeve 28. As illustrated in FIGS. 5A and 6, the distal interference diameters 66 are sized and configured to engage corresponding recesses and / or slots 48 provided in the sheath hub 20 for securing the locking sleeve 28 to the sheath hub 20, and the distal interference diameter 66 seat against the proximal end of the sheath hub 20.

[0100] The locking sleeve 28 includes a guide 31 projecting from the outer surface 68 of the locking sleeve 28. The guide 31 engages a corresponding shaped locking channel 38 in the introducer locking hub 30. The guide 31 extends radially from the outer surface 68 and at least partially around the circumference of the outer surface 68. As provided in FIG. 6, the top surface of the guide 31 does not extend beyond the outer surface of the introducer locking hub 30 when the locking sleeve 28 and the introducer locking hub 30 are coupled. For example, the height of the guide 31 corresponds to the wall thickness of the introducer locking hub 30 proximate the guide when the locking sleeve 28 and the introducer locking hub 30 are coupled. In some examples, the top surface of the guide 31 is recessed with respect to the outer surface of the introducer locking hub 30. That is, the height of the guide 31 is less than the wall thickness of the introducer locking hub 30. In some examples, the height of the guide 31 is greater than a wall thickness of the introducer locking hub 30 such that the top surface of the guide 31 extends beyond the outer surface of the introducer locking hub 30 when the locking sleeve 28 and the introducer locking hub 30 are coupled. In some examples, the height / axial length of the guide 31 is between about 0.050 inches and about 0.10 inches. In some examples that height / axial length of the guide 31 is about 0.075 inches.

[0101] As illustrated in FIGS. 10D-10F, the guide 31 is a cylindrically shaped projection. However, it is contemplated that the guide 31 may have any other regular or irregular shape that would facilitate movement of the guide 31 within the locking channel 38 of the introducer locking hub 30. For example, the guide 31 may have an elongated hexagon shape. The guide 31 can have a diameter / width ranging from about 0.05 inches to about 0.20 inches. Preferably the guide 31 has a diameter / width of about 0.100 inches.

[0102] In general, the locking sleeve 28 can comprise polycarbonate, but in some examples, the locking sleeve 28 can comprise rigid plastic, or any other material suitable for providing a strong locking connector for an introducer 6 (metal, composite, etc.).

[0103] FIGS. 2-6 illustrate the introducer locking hub 30 coupled to the locking sleeve 28. FIGS. 8A-8F show the introducer locking hub 30 coupled to the introducer 6. FIGS. 9A-9F provide multiple view of the introducer locking hub 30. As described herein, the introducer 6 is fixedly coupled to the introducer locking hub 30. The introducer locking hub 30 couples with the locking sleeve 28 to fix the position the introducer 6 (axially and rotationally) with respect to the locking sleeve 28 / sheath 8. Each of the introducer 6 and introducer locking hub 30 are described in more detail as follows.

[0104] FIGS. 8A-8F illustrate the introducer locking hub 30 with the introducer 6 coupled thereto. Example introducer sheaths are described, for example in U.S. Patent Nos. 8,690,936 and 8,790,387, the disclosures of which are incorporated herein by reference. As provided in the cross-sectional views of FIGS. 5A and 5B, the introducer 6 is coupled to the introducer locking hub 30 and extends beyond the distal end of the introducer locking hub 30 body and into the sheath 8. When coupled to the sheath hub 20, the introducer 6 extends through the central lumen 56 of the locking sleeve 28, the sheath hub 20 and the central lumen of the sheath 8. As will be descried herein, the sheath 8 generally comprises a radially expandable tubular structure. Passage of the introducer 6 through the sheath 8 and into a patient’s vasculature causes the blood vessel to radially expand to about the diameter of the sheath 8. That is, the diameter of the central lumen of the sheath 8 is generally abuts the outer diameter of the introducer 6 such that the introducer 6 provides a mechanism to expand a patient’s vessel to accept the sheath.

[0105] As provided in FIGS. 8A-8F, the introducer 6 is formed as an elongate body with a central lumen extending therethrough. As shown in FIGS. 5A and 5B, the central lumen of the introducer is aligned with the central lumens of the introducer locking hub 30, the sheath hub 20 and the sheath 8. The introducer 6 is received within a recessed opening 39 provided on an interior surface of the introducer locking hub 30, the recessed opening 39 axiallyaligned with the central lumen 45 of the introducer locking hub 30. The introducer 6 is coupled to the introducer locking hub 30 at the recessed opening 39. In an example system, the introducer 6 has a diameter corresponding to, or less than, the diameter of the recessed opening 39. In some examples, the introducer 6 is fixedly coupled to the introducer locking hub 30 at the recessed opening 39. For example, the introducer 6 is coupled to the recessed opening 39 of the introducer locking hub 30 by at least one of a press fit, an interference fit, a snap fit, a mechanical fastener, a chemical fastener (for example, an adhesive), a weld, a thermal process, and / or any other suitable coupling process known in the art.

[0106] As described herein, the introducer 6 has a central lumen that aligns with the central lumen 45 of the introducer locking hub 30. This joined lumen allows for the passage of surgical equipment and / or medical devices to the treatment site (for example, a guide wire). In an example system, and as provided in FIGS. 5A and 5B, the central lumen of the introducer 6 has a diameter corresponding to at least a portion of the diameter of the central lumen 45 of the introducer locking hub 30. In general, the corresponding diameter portion is adjacent the distal end of the central lumen 45. In some examples, the diameter of the central lumen 45 at the distal end of the introducer locking hub 30 is slightly larger than the diameter of the central lumen passing through the introducer 6. The central lumen 45 can also define a decreasing tapered portion 41 between the proximal end and the distal end of the introducer locking hub 30 (see FIG. 6). The corresponding diameter portion and decreasing tapered portion 41 allows for smooth transition and delivery of surgical equipment and / or medical device through the introducer locking hub 30 and into the central lumen of the introducer 6.

[0107] As illustrated in FIGS. 9A-9F, the introducer locking hub 30 includes a introducer locking hub body 32 having a proximal end 70 and a distal end 72 and defining a central lumen 45 extending therethrough. The introducer locking hub body 32 has a first (middle) portion 33, a second (distal) portion 35 which extends distally from the first portion 33 and a third (proximal) portion 37 which extends proximally from the first portion 33. The first portion 33 includes the cylindrically-shaped recessed opening 39 for receiving and retaining the introducer 6 and an outer surface 43. In some examples, the recessed opening 39 has a diameter ranging between 0.15 inches and about 0.25 inches. In some examples, the recessed opening 39 has a diameter ranging between 0. 17 inches and about 0.20 inches. In some examples, the recessed opening has a diameter of about 0.194 inches.

[0108] The third (proximal) portion 37 of the introducer locking hub 30 includes the decreasing tapered portion 41 of the central lumen 45. The decreasing taper portion 41 defining a frustoconical shape with decreasing taper / diameter from the proximal to the distalend of the sheath. It is contemplated that the tapered portion 41 has a minimum diameter of about 0.007 inches and a maximum diameter of about 0.194 inches.

[0109] As illustrated in FIGS. 5 A and B, when coupled, the central lumen 56 of the locking sleeve 28 is aligned with the central lumen 45 of the introducer locking hub 30. In some examples, the central lumen 56 of the locking sleeve 28 is coaxial with the central lumen 45 of the introducer locking hub 30. When coupled, the proximal end of the locking sleeve 28 is received within the central lumen 45 of the introducer locking hub 30. The proximal end surface of the locking sleeve 28 is adjacent a shoulder 50 provided on an inner surface of the central lumen 45 of the introducer locking hub 30. As illustrated in FIGS. 5A and 5B, the central lumen 45 of the introducer locking hub 30 includes a first portion 52 having a first diameter adjacent the proximal end of the introducer locking hub 30, and a second portion 54 having a second, larger, diameter adjacent the distal end of the introducer locking hub 30. The recessed opening 39 can be considered either a component of the first portion 52 of the central lumen 45, or a separate component of the central lumen 45 located between the first (proximal) portion 52 and the second (distal) portion 54. When the locking sleeve 28 and introducer locking hub 30 are coupled, at least a portion of the sleeve body 29 of the locking sleeve 28 is received within the second portion 54 (larger portion) of the central lumen 45 of the introducer locking hub 30. The central lumen 56 of the locking sleeve 28 is aligned with the central lumen 45 of the introducer locking hub 30 such that they are co-axial and form a smooth inner surface along the combined central lumens of the introducer locking hub 30 and the locking sleeve 28.

[0110] As described herein, the locking sleeve 28 couples to the introducer locking hub 30 via engagement between the guide 31 on the locking sleeve 28 and the locking channel 38 provided in the introducer locking hub 30. As provided in FIGS. 9A-9F, the introducer locking hub 30 includes two locking channels 38. However, it is contemplated that the introducer locking hub 30 can include one locking channel 38 or more than two locking channels 38. The locking channel 38 can be is formed a recess or groove in a surface of the introducer locking hub 30, as a slotted opening, a clip, or as any other feature capable of receiving and securing the guide 31 projecting from the outer surface of the locking sleeve 28 with the introducer locking hub 30. Illustrated in FIG. 9B, the locking channels 38 provide an interface to secure the locking sleeve 28 to the introducer locking hub 30 and ensure a fixed axial position between the introducer 6 and the sheath 8.

[0111] The locking channel 38 is formed on the distal end of the introducer locking hub 30. The locking channel 38 includes an opening on the distal end surface that leads to an angledguide portion 40 that transitions to a locking portion 42. The guide portion 40 is configured to direct the guide 31 of the locking sleeve 28 in an axial and circumferential direction along the side wall of the guide portion 40 towards the locking portion 42 upon rotation of the introducer locking hub 30 and / or the locking sleeve 28. The locking portion 42 is configured to securely engage the guide 31, fixing the axial position of the introducer locking hub 30 with respect to the locking sleeve 28. As illustrated in FIG. 9B, the guide portion 40 of the locking channel 38 extends from the distal end of the introducer locking hub 30 axially towards the proximal end of the introducer locking hub 30 and circumferentially around the introducer locking hub 30. For example, the guide portion 40 of the locking channel 38 can be described as extending helically around / along a length of the introducer locking hub 30 or on an angle from the distal end of the introducer locking hub 30.

[0112] As illustrated in FIGS. 9B and 9D, the locking portion 42 of the locking channel 38 extends at an angle from the end of the guide portion 40. As provided in FIG. 9B, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is greater than 90-degrees. In some examples, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is about 120-degrees. In an example system, the locking portion 42 extends around a portion of the circumference of the introducer locking hub 30. The locking portion 42 can extend parallel to the distal end of the introducer locking hub 30. In an example system, the length of the guide portion 40 (measured along its centerline) is greater than a length of the locking portion 42 (measured along its centerline). In some examples, the length of the guide portion 40 equals or is less than a length of the locking portion 42.

[0113] The locking portion 42 can include a catch 44 for securing the guide 31 within the locking portion 42 of the locking channel 38 and forming a partial barrier for the guide 31 within the locking portion 42. As illustrated in FIG. 9B, the catch 44 includes a projection that extends from a side wall 74 of the locking portion 42 and releasably secures the guide 31 within the locking channel 38. The catch 44 extends from the side wall 42a of the locking portion 42 in a proximal direction towards the center line of the locking portion 42 and has a height sufficient to retain the guide 31 between the catch 44 and the end of the locking portion 42.

[0114] The distal end surface 72 of the introducer locking hub 30 can include features for biasing the guide 31 towards and into the locking channel 38. For example, the distal end of the introducer locking hub 30 can include a tapered surface angled toward an opening of the locking channel 38. As illustrated in FIG. 9B, the distal end 72 of the introducer locking hub30 includes a first tapered surface 76 (angled towards a leading edge of the opening of the locking channel 38 and a second tapered surface 78 angled towards the trailing edge of the opening of the locking channel 38.

[0115] In use, engagement between the guide 31 and the guide portion 40 of the locking channel 38 is configured to bias the locking sleeve 28 in a proximal axial direction toward the proximal end 70 of the introducer locking hub 30 (towards a locked position) when the locking sleeve 28 is rotated in a first axial direction. In this direction the guide 31 advances toward the locking portion 42 of the locking channel 38 into the locked position. Alternatively, engagement between the guide 31 and the locking portion 42 of the locking channel 38 is configured to bias the locking sleeve 28 in a distal axial direction toward the distal end of the introducer locking hub 30 (towards an unlocked position) when the locking sleeve 28 is rotated in a second (opposite) axial direction. In the second direction, the guide31 advances away from the locking portion 42 of the locking channel 38, to the unlocked position. When the guide 31 is in the locked position and retained with by locking portion 42 by catch 44, rotation in the second direction causes the guide 31 to bias against the catch 44 overcoming the oppositional forces of the catch 44, and moving the guide 31 from the locked to the unlocked position.

[0116] As illustrated in FIGS. 8A-9F, the outer surface of the introducer locking hub body32 includes gripping features and / or surfaces for a physician or technician to use when manipulating the introducer locking hub 30. As provided in FIG. 9B, the introducer locking hub body 32 can include a two recessed gripping surfaces 34 on opposite sides of the longitudinal axis of the introducer locking hub 30. When the introducer locking hub 30 is viewed from the side, the gripping surfaces 34 define a dog-bone / barbell shape to the hub body 32, i.e., a shape having a smaller diameter / width center portion and larger diameter / width end portions. In an example system, the gripping surfaces 34 are provided along at least 40% of the length of the introducer locking hub body 32. In some examples, the gripping surfaces 34 are provided along at least 50% of the length of the introducer locking hub body 32.

[0117] In general, the introducer locking hub 30 can comprise polycarbonate, but in some examples the introducer locking hub 30 can comprise rigid plastic, or any other material suitable for providing a locking mechanism for an introducer 6 (metal, composite, etc.).

[0118] As described herein, the introducer device / sheath assembly includes an expandable sheath 8 extending distally from the sheath hub 20. The expandable sheath 8 has a central lumen to guide passage of the delivery apparatus 10 for the medical device 12 (for example,an implant such as a prosthetic heart valve). In some examples, the introducer device / sheath assembly need not include the sheath hub 20. For example, the sheath 8 can be an integral part of a component of the sheath assembly, such as the guide catheter.

[0119] In certain examples, the expandable sheath 8 can comprise a plurality of coaxial layers extending along at least a portion of the length of the sheath 8. The structure of the coaxial layers is described in more detail herein with respect to FIGS. 11-23. Example expandable sheaths including coaxial layers are described, for example, in U.S. Patent Application No. 16 / 378,417, entitled “Expandable Sheath,” and U.S. Patent Application No. 17 / 716,882, entitled “Expandable Sheath,” the disclosures of which are herein incorporated by reference.

[0120] Various examples of the coaxial layered structure of the sheath 8 are described herein. For example, in reference to the example sheath 8 illustrated in FIGS. 11-14, the expandable sheath 8 can include a number of layers including an inner layer 102 (also referred to as an inner liner), a second layer 104 disposed around and radially outward of the inner layer 102, a third layer 106 disposed around and radially outward of the second layer 104, and a fourth outer layer 108 (also referred to as an outer liner) disposed around and radially outward of the third layer 106. In the illustrated configuration, the inner layer 102 can define the lumen 112 of the sheath extending along a central axis 114 through which the delivery apparatus travels into the patient’s vessel in order to deliver, remove, repair, and / or replace a prosthetic device, moving in a direction along the longitudinal axis of the sheath 8.

[0121] Referring to FIG. 12, when the sheath 8 is in an unexpanded state, various layers of the sheath, for example, the inner layer 102 and / or the outer layer 108, can form longitudinally-extending folds or creases such that the surface of the sheath comprises a plurality of folds or ridges 126. The ridges 126 can be circumferentially spaced apart from each other by longitudinally-extending valleys 128. When the sheath expands beyond its natural diameter DI, the ridges 126 and the valleys 128 can level out or be taken up as the surface radially expands and the circumference increases, as further described herein. When the sheath 8 collapses back to its natural diameter, the ridges 126 and valleys 128 can reform.

[0122] In certain examples, the inner layer 102 and / or the outer layer 108 can comprise a relatively thin layer of polymeric material. For example, the thickness of the inner layer 102 can be from 0.01 mm to 0.5 mm, 0.02 mm to 0.4 mm, or 0.03 mm to 0.25 mm. In some examples, the thickness of the outer layer 108 can be from 0.01 mm to 0.5 mm, 0.02 mm to 0.4 mm, or 0.03 mm to 0.25 mm.

[0123] In certain examples, the inner layer 102 and / or the outer layer 108 can comprise a lubricious, low-friction, and / or relatively non-elastic material. For example, the inner layer 102 and / or the outer layer 108 can comprise a polymeric material having a modulus of elasticity of 400 Mpa or greater. Exemplary materials can include ultra-high-molecular- weight polyethylene (UHMWPE) (for example, Dyneema®), high-molecular-weight polyethylene (HMWPE), or polyether ether ketone (PEEK). With regard to the inner layer 102 in particular, such low coefficient of friction materials can facilitate passage of the prosthetic device through the lumen 1 12. Other suitable materials for the inner and outer layers can include polyimide, polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyamide, polyether block amide (for example, Pebax), and / or combinations of any of the above. In some examples, the sheath 8 can include a lubricious liner on the inner surface of the inner layer 102. Examples of suitable lubricious liners include materials that can further reduce the coefficient of friction of the inner layer 102, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for a lubricious liner also include other materials desirably having a coefficient of friction of 0.1 or less.

[0124] Additionally, some examples of the sheath 8 can include an exterior hydrophilic coating on the outer surface of the outer layer 108. Such a hydrophilic coating can facilitate insertion of the sheath 8 into a patient’s vessel, reducing potential damage. Examples of suitable hydrophilic coatings include the HarmonyTM Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM medical coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings (for example, PTFE, polyethylene, polyvinylidene fluoride), are also suitable for use with the sheath 8. Such hydrophilic coatings may also be included on the inner surface of the inner layer 102 to reduce friction between the sheath and the delivery apparatus, thereby facilitating use and improving safety. In some examples, a hydrophobic coating, such as Perylene, may be used on the outer surface of the outer layer 108 or the inner surface of the inner layer 102 in order to reduce friction.

[0125] In certain examples, the second layer 104 can be a braided layer. FIGS. 13A and 13B illustrate the sheath 8 with the outer layer 108 removed to expose the elastic third layer 106. With reference to FIGS. 13A and 13B, the braided second layer 104 can comprise a plurality of members or filaments 110 (for example, metallic or synthetic wires or fibers) braided together. The braided second layer 104 can have any desired number of filaments 110, which can be oriented and braided together along any suitable number of axes. Forexample, with reference to FIG. 13B, the filaments 110 can include a first set of filaments 110A oriented parallel to a first axis A, and a second set of filaments HOB oriented parallel to a second axis B. The filaments 110A and 110B can be braided together in a biaxial braid such that filaments 110A oriented along axis A form an angle 0 with the filaments HOB oriented along axis B. In certain examples, the angle 0 can be from 5° to 70°, 10° to 60°, 10° to 50°, or 10° to 45°. In the illustrated example, the angle 0 is 45°. In some examples, the filaments 110 can also be oriented along three axes and braided in a triaxial braid, or oriented along any number of axes and braided in any suitable braid pattern. The braided second layer 104 can extend along substantially the entire length L of the sheath 8, or alternatively, can extend only along a portion of the length of the sheath. In particular examples, the filaments 110 can be wires made from metal (for example, Nitinol, stainless steel, etc.), or any of various polymers or polymer composite materials, such as carbon fiber. In certain examples, the filaments 110 can be round, and can have a diameter of from 0.01 mm to 0.5 mm, 0.03 mm to 0.4 mm, or 0.05 mm to 0.25 mm. In some examples, the filaments 110 can have a flat cross-section with dimensions of 0.01 mm x 0.01 mm to 0.5 mm x 0.5 mm, or 0.05 mm x 0.05 mm to 0.25 mm x 0.25 mm. In one aspect, filaments 110 having a flat cross-section can have dimensions of 0.1 mm x 0.2 mm. However, other geometries and sizes are also suitable for certain aspects. If braided wire is used, the braid density can be varied. Some examples have a braid density of from ten picks per inch to eighty picks per inch, and can include eight wires, sixteen wires, or up to fifty-two wires in various braid patterns. In some examples, the second layer 104 can be laser cut from a tube, or laser-cut, stamped, punched, etc., from sheet stock and rolled into a tubular configuration. The second layer 104 can also be woven or knitted, as desired.

[0126] The third layer 106 can be a resilient, elastic layer (also referred to as an elastic material layer). In certain examples, the elastic third layer 106 can be configured to apply radially inward force to the underlying inner layer 102 and second layer 104 in a radial direction (for example, toward the central axis 114 of the sheath) when the sheath expands beyond its natural diameter by passage of the delivery apparatus through the sheath. Stated differently, the elastic third layer 106 can be configured to apply encircling / radially inward pressure to the layers of the sheath beneath the elastic third layer 106 to counteract expansion of the sheath. The radially inwardly directed force is sufficient to cause the sheath to collapse radially back to its unexpanded state after the delivery apparatus is passed through the sheath.

[0127] In the illustrated example, the elastic third layer 106 can comprise one or more members configured as strands, ribbons, or elastic bands 116 helically wrapped around thebraided second layer 104. For example, in the illustrated aspect the elastic third layer 106 comprises two elastic bands 116A and 116B wrapped around the braided second layer 104 with opposite helicity, although the elastic layer may comprise any number of bands depending upon the desired characteristics. The elastic bands 116A and 116B can be made from, for example, any of a variety of natural or synthetic elastomers, including silicone rubber, natural rubber, any of various thermoplastic elastomers, polyurethanes such as polyurethane siloxane copolymers, urethane, plasticized polyvinyl chloride (PVC), styrenic block copolymers, polyolefin elastomers, etc. In some examples, the elastic layer can comprise an elastomeric material having a modulus of elasticity of 200 MPa or less. In some examples, the elastic third layer 106 can comprise a material exhibiting an elongation to break of 200% or greater, or an elongation to break of 400% or greater. The elastic third layer 106 can also take other forms, such as a tubular layer comprising an elastomeric material, a mesh, a shrinkable polymer layer such as a heat-shrink tubing layer, etc. In lieu of, or in addition to, the elastic third layer 106, the sheath 8 may also include an elastomeric or heatshrink tubing layer around the outer layer 108. Examples of such elastomeric layers are disclosed in U.S. Publication No. 2014 / 0379067, U.S. Publication No. 2016 / 0296730, and U.S. Publication No. 2018 / 0008407, which are incorporated herein by reference. In some examples, the elastic third layer 106 can also be radially outward of the polymeric outer layer 108.

[0128] In certain examples, one or both of the inner layer 102 and / or the outer layer 108 can be configured to resist axial elongation of the sheath 8 when the sheath expands. More particularly, one or both of the inner layer 102 and / or the outer layer 108 can resist stretching against longitudinal forces caused by friction between a prosthetic device and the inner surface of the sheath 8 such that the length L remains substantially constant as the sheath expands and contracts. As used herein with reference to the length L of the sheath, the term “substantially constant” means that the length L of the sheath increases by not more than 1%, by not more than 5%, by not more than 10%, by not more than 15%, or by not more than 20%. Meanwhile, with reference to FIG. 13B, the filaments 110A and 110B of the braided second layer 104 can be allowed to move angularly relative to each other such that the angle 0 changes as the sheath expands and contracts. This, in combination with the longitudinal ridges 126 in the inner layer 102 and outer layer 108, can allow the lumen 112 of the sheath to expand as a prosthetic device is advanced through it.

[0129] For example, the inner layer 102 and the outer layer 108 can be heat-bonded during the manufacturing process such that the braided second layer 104 and the elastic third layer106 are encapsulated between the inner layer 102 and outer layer 108. More specifically, in some examples the inner layer 102 and the outer layer 108 can be adhered to each other through the spaces between the filaments 110 of the braided second layer 104 and / or the spaces between the elastic bands 116. The inner layer 102 and outer layer 108 can also be bonded or adhered together at the proximal and / or distal ends of the sheath. In some examples, the inner layer 102 and outer layer 108 are not adhered to the filaments 110. This can allow the filaments 110 to move angularly relative to each other, and relative to the inner layer 102 and outer layer 108, allowing the diameter of the braided second layer 104, and thereby the diameter of the sheath, to increase or decrease. As the angle 0 between the filaments 110A and HOB changes, the length of the braided second layer 104 can also change. For example, as the angle 0 increases, the braided second layer 104 can foreshorten, and as the angle 0 decreases, the braided second layer 104 can lengthen to the extent permitted by the areas where the inner layer 102 and outer layer 108 are bonded. However, because the braided second layer 104 is not adhered to the inner layer 102 and outer layer 108, the change in length of the braided layer that accompanies a change in the angle 0 between the filaments 110A and HOB does not result in a significant change in the length L of the sheath.

[0130] FIG. 14 illustrates radial expansion of the sheath 8 as a prosthetic device (for example, medical device 12) is passed through the sheath 8 in the direction of arrow 132 (for example, distally). As the prosthetic device (medical device 12) is advanced through the sheath 8, the sheath can resiliently expand to a second diameter D2 that corresponds to a size or diameter of the prosthetic device. As the prosthetic device (medical device 12) is advanced through the sheath 8, the prosthetic device can apply longitudinal force to the sheath in the direction of motion by virtue of the frictional contact between the prosthetic device and the inner surface of the sheath. However, as noted herein, the inner layer 102 and / or the outer layer 108 can resist axial elongation such that the length L of the sheath remains constant, or substantially constant. This can reduce or prevent the braided layer second 104 from lengthening, and thereby constricting the lumen 112.

[0131] Meanwhile, the angle 0 between the filaments 110A and 110B can increase as the sheath expands to the second diameter D2 to accommodate the prosthetic valve. This can cause the braided second layer 104 to foreshorten. However, because the filaments 110 are not engaged or adhered to the inner layer 102 or outer layer 108, the shortening of the braided second layer 104 attendant to an increase in the angle 0 does not affect the overall length L of the sheath. Moreover, because of the longitudinally-extending ridges 126 formed in the innerlayer 102 and outer layer 108, the inner layer 102 and outer layer 108 can expand to the second diameter D2 without rupturing, in spite of being relatively thin and relatively nonelastic. In this manner, the sheath 8 can resiliently expand from its natural diameter DI to a second diameter D2 that is larger than the diameter DI as a prosthetic device is advanced through the sheath, without lengthening, and without constricting. Thus, the force required to push the prosthetic implant through the sheath is significantly reduced.

[0132] Additionally, because of the radial force applied by the elastic third layer 106, the radial expansion of the sheath 8 can be localized to the specific portion of the sheath occupied by the prosthetic device. For example, with reference to FIG. 14, as the prosthetic device (medical device 12) moves distally through the sheath 8, the portion of the sheath immediately proximal to the prosthetic device (for example, medical device 12) can radially collapse back to the initial diameter DI under the influence of the elastic third layer 106. The inner layer and outer layer 108 can also buckle as the circumference of the sheath is reduced, causing the ridges 126 and the valleys 128 to reform. This can reduce the size of the sheath required to introduce a prosthetic device of a given size. Additionally, the temporary, localized nature of the expansion can reduce trauma to the blood vessel into which the sheath is inserted, along with the surrounding tissue, because only the portion of the sheath occupied by the prosthetic device expands beyond the sheath’s natural diameter and the sheath collapses back to the initial diameter once the device has passed. This limits the amount of tissue that must be stretched in order to introduce the prosthetic device, and the amount of time for which a given portion of the vessel must be dilated.

[0133] In some examples layered sheath 8 structure, FIGS. 15-23 illustrate various features of the coaxial layered structure of the expandable sheath 8 of FIG. 1 according to another aspect. Similar reference numbers are used to describe like elements. It is to be understood that the variations (for example, materials and alternate configurations) described herein with reference to FIGS. 11-14 can also apply to the example shown in FIGS. 15-23. Furthermore, the variations described herein with reference to FIGS. 15-23 can also be applied to the sheath described in FIGS. 11-14.

[0134] Similar to various examples of the sheath 8 described herein in reference to FIGS. 11-14, the sheath 8 of FIGS. 15-23 includes a plurality of layers. For example, the sheath 8 illustrated in FIGS. 15-23, also includes an inner layer 202 and an outer layer 204 disposed around the inner layer 202. The inner layer 202 can define a central lumen 212 through which the delivery apparatus travels into the patient’s vessel in order to deliver, remove, repair, and / or replace a prosthetic device, moving in a direction along the longitudinal axis X.Similar to the sheath illustrated in FIGS. 11-14, as the prosthetic device passes through the sheath 8, the sheath 8 locally expands from a first, resting / unexpanded diameter to a second, expanded diameter to accommodate the prosthetic device. After the prosthetic device passes through a particular location of the sheath 8, each successive expanded portion or segment of the sheath 8 at least partially returns to the smaller, resting / unexpanded diameter. In this manner, the sheath 8 can be considered self-expanding, in that it does not require use of a balloon, dilator, and / or obturator to expand.

[0135] Similar to the examples herein, the inner and outer layers 202, 204 can comprise any suitable materials. Suitable materials for the inner layer 202 include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyether block amide (for example, Pebax), and / or combinations thereof. In an example sheath 8, the inner layer 202 can comprise a lubricious, low-friction, or hydrophilic material, such as PTFE. Such low coefficient of friction materials can facilitate passage of the prosthetic device through the lumen defined by the inner layer 202. In some examples, the inner layer 202 can have a coefficient of friction of less than about 0.1. Some examples of the sheath 8 can include a lubricious liner on the inner surface of the inner layer 202. Examples of suitable lubricious liners include materials that can further reduce the coefficient of friction of the inner layer 202, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for a lubricious liner also include other materials desirably having a coefficient of friction of about 0.1 or less.

[0136] Suitable materials for the outer layer 204 include nylon, polyethylene, Pebax, HDPE, polyurethanes (for example, Tecoflex), and other medical grade materials. In one example, the outer layer 204 can comprise high density polyethylene (HDPE) and Tecoflex (or other polyurethane material) extruded as a composite. In some examples, the Tecoflex can act as an adhesive between the inner layer 202 and the outer layer 204 and may only be present along a portion of the inner surface of the outer layer 204. Other suitable materials for the inner and outer layers are also disclosed in U.S. Patent Nos. 8,690,936 and 8,790,387, which are incorporated herein by reference.

[0137] Additionally, some examples of the sheath 8 include an exterior hydrophilic coating on the outer surface of the outer layer 204. Such a hydrophilic coating can facilitate insertion of the sheath 8 into a patient’s vessel. Examples of suitable hydrophilic coatings include the Harmony TM Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM medical coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings (forexample, PTFE, polyethylene, poly vinylidene fluoride), are also suitable for use with the sheath 8.

[0138] FIGS. 15-23 illustrate an example sheath system 200. FIG. 16 provides a partial cross-section of the distal end of the sheath 8 along section line 16-16 identified in FIG. 15. As described herein, the sheath 8 can be inserted into a vessel (for example, the femoral or iliac arteries) by passing through the skin of patient, such that a soft tip portion 206 at the distal end 210 of the sheath 8 is inserted into the vessel. As best seen in FIG. 16, the soft tip portion 206 can comprise, in some examples, low density polyethylene (LDPE) and can be configured to minimize trauma or damage to the patient’s vessels as the sheath is navigated through the vasculature. For example, the soft tip portion 206 can be slightly tapered to facilitate passage through the vessels. The soft tip portion 206 can be secured to the distal end 210 of the sheath 8, such as by thermally bonding the soft tip portion 206 to the inner and outer layers of the sheath 8. Such a soft tip portion 206 can be provided with a lower hardness than the other portions of the sheath 8. In some examples, the soft tip portion 206 can have a Shore hardness from about 25D to about 40D. The soft tip portion 206 is configured to be radially expandable to allow a prosthetic device to pass through the distal opening of the sheath 8. For example, the soft tip portion 206 can be formed with a weakened portion, such as an axially extending score line or perforated line that is configured to split and allow the soft tip portion 206 to expand radially when the prosthetic device passes therethrough.

[0139] FIG. 17 shows a cross-sectional view of the sheath 8 taken near the distal end 210 of the sheath 8 as indicated by section line 17-17 in FIG. 16. As illustrated in FIGS. 16 and 17, the sheath 8 can include at least one radiopaque filler or marker, such as a discontinuous, or C-shaped, band / marker 216 positioned near the distal end 210 of the sheath 8. The marker 216 can be associated with the inner and / or outer layers 202, 204 of the sheath 8. For example, as shown in FIG. 17, the marker 216 can be positioned between the inner layer 202 and the outer layer 204. In some examples, the marker 216 can be associated with the outer surface of the outer layer 204. In some examples, the marker 216 can be embedded or blended within the inner or outer layers 202, 204.

[0140] FIGS. 18 and 19 show additional cross-sections taken at different points along the sheath 8. FIG. 18 shows a cross-section of a segment of the sheath near the proximal end 214 of the sheath 8, as indicated by section line 18-18 in FIG. 15. At this location, the sheath 8 includes the inner layer 202, outer layer 204, elastic outer layer 250 / outer jacket, and the strain relief layer 26. At this location, near the proximal end of the sheath 8, the inner and outer layers 202, 204 are substantially tubular. Here the inner and outer layers 202, 204 canbe formed without any slits or folded portions in the layers. By contrast, as described herein, the inner and outer layers 202, 204 at different locations along the sheath 8 (for example, at the point indicated by section line 19-19 in FIG. 15 and / or the point indicated by section line 22-22 in FIG. 21) can have a different configuration.

[0141] As shown in FIG. 19, the inner layer 202 can be arranged to form a substantially cylindrical central lumen 212 therethrough. Inner layer 202 can include one or more folded portions 218. In the example shown in FIG. 19, inner layer 202 is arranged to have one folded portion 218 that can be positioned on either side of the inner layer 202. Inner layer 202 can be continuous, in that there are no breaks, slits, or perforations in inner layer 202. Outer layer 204 can be arranged in an overlapping fashion such that an overlapping portion 220 overlaps at least a part of the folded portion 218 of the inner layer 202. As shown in FIG. 19, the overlapping portion 220 also overlaps an underlying portion 222 of the outer layer 204. The underlying portion 222 can be positioned to underlie both the overlapping portion 220 of the outer layer 204, as well as the folded portion 218 of the inner layer 202. Thus, the outer layer 204 can be discontinuous, in that it includes a slit or a cut in order to form the overlapping portion 220 and underlying portion 222. In other words, a first edge 224 of the outer layer 204 is spaced apart from a second edge 225 of the outer layer 204 so as not to form a continuous layer.

[0142] As shown in FIG. 19, the sheath 8 can also include a thin layer of bonding or adhesive material 228 positioned between the inner layer 202 and outer layer 204. In one example, the adhesive material 228 can comprise a polyurethane material such as Tecoflex. The adhesive material 228 can be positioned on an inner surface 230 of at least a portion of the outer layer 204 so as to provide adhesion between selected portions of the inner layer 202 and outer layer 204. For example, the outer layer 204 may only include a Tecoflex layer (adhesive material 228) around the portion of the inner surface 230 that faces the lumenforming portion of the inner layer 202. In other words, the Tecoflex layer (adhesive material 228) can be positioned so that it does not contact the folded portion 218 of the inner layer 202 in some examples. In some examples, the Tecoflex can be positioned in different configurations as desired for the particular application. For example, as shown in FIG. 19, the Tecoflex layer can be positioned along the entire inner surface 230 of the outer layer 204. In some examples, the Tecoflex layer can be applied to the outer surface of the inner layer 202 instead of the inner surface of the outer layer 204. The Tecoflex layer can be applied to all or selected portions on the inner layer 202; for example, the Tecoflex layer can be formed only on the portion of the inner layer 202 that faces the lumen-forming portion of the outer layer204 and not on the folded portion 218. The configuration of FIG. 19 allows for radial expansion of the sheath 8 as an outwardly directed radial force is applied from within (for example, by passing a medical device such as a prosthetic heart valve through the central lumen 212). As radial force is applied, the folded portion 218 can at least partially separate, straighten, and / or unfold, and / or the overlapping portion 220 and the underlying portion 222 of the outer layer 204 can slide circumferentially with respect to one another, thereby allowing the diameter of central lumen 212 to enlarge.

[0143] In this manner, the sheath 8 is configured to expand from a resting / unexpanded configuration (FIG. 19) to an expanded configuration shown in FIG. 20. In the expanded configuration, as shown in FIG. 20, a gap 232 can form between the longitudinal edges of the overlapping portion 220 and the underlying portion 222 of the outer layer 204. As the sheath 8 expands at a particular location, the overlapping portion 220 of the outer layer 204 can move circumferentially with respect to the underlying portion 222 as the folded portion 218 of the inner layer 202 unfolds. This movement can be facilitated by the use of a low-friction material for inner layer 202, such as PTFE. Further, the folded portion 218 can at least partially separate and / or unfold to accommodate a medical device having a diameter larger than that of central lumen 212 in the resting / unexpanded configuration. As shown in FIG. 20, in some examples, the folded portion of the inner layer 202 can completely unfold, so that the inner layer 202 forms a cylindrical tube at the location of the expanded configuration.

[0144] Similar to the example sheath 8 in FIG. 14, the sheath 8 is configured to locally expands at a particular location corresponding to the location of the medical device along the length of the central lumen 212, and then locally contracts once the medical device has passed that particular location. Thus, a bulge may be visible, traveling longitudinally along the length of the sheath 8 as a medical device is introduced through the sheath 8, representing continuous local expansion and contraction as the device travels the length of the sheath 8. Each segment of the sheath 8 will locally contract after removal of any radial outward force such that the sheath 8 at least partially returns to the original resting / unexpanded diameter of central lumen 212. Similar to the example sheath described herein, an elastic outer layer 250 can (optionally) be provided along the sheath 8, urging the inner and outer layers 202, 204 back to the unexpanded configuration.

[0145] The layers 202, 204 of sheath 8 can be configured having the folded portion 218 as shown in FIG. 19 along at least a portion of the length of the sheath 8. In some examples, the inner and outer layers 202, 204 can be configured as shown in FIG. 19 along the length A (FIG. 15) such that the folded portion 218 extends from a location adjacent the soft tipportion 206 to a location closer to the proximal end 214 of the sheath 8, adjacent and / or under the distal end of the strain relief layer 26. In this matter, the sheath 8 is expandable and contractable only along a portion of the length of the sheath corresponding to length A (which can correspond to the section of the sheath inserted into the narrowest section of the patient’s vasculature).

[0146] In some examples, the folded portion 218 portion extends from a location adjacent the soft tip portion 206 under the strain relief layer 26, as illustrated in FIG. 21. In this example, the folded structure of the inner layer 202 extends from the soft tip portion 206, under the strain relief layer 26 and along the tapered portion 248 of the strain relief layer 26.

[0147] FIGS. 22 and 23 illustrate cross-sectional views of the sheath 8 taken along the strain relief layer 26 at section line 22-22 in FIG. 21. In this example, the folded portion 218 of the inner layer 202 extends under the strain relief layer 26. FIG. 22 shows a cross-section of the sheath 8 in a resting / unexpanded configuration having an inner diameter DI. FIG. 23 shows a cross-section of the sheath 8 in a (partially) expanded configuration, having an inner diameter D2, where D2 is greater than DI.

[0148] As shown in FIGS. 22-23, in some examples, the overlapping portion 220 does not overlap the entire folded portion 218 of the inner layer 202, and thus a portion of the folded portion 218 can be directly adjacent to the strain relief layer 26 in locations where the strain relief layer 26 is present. In locations where the strain relief layer 26 is not present, part of the folded portion 218 may be visible from the outside of the sheath 8, as seen in FIG. 21 (and / or visible through an elastic outer layer 250 described in more detail herein). In these examples, the sheath 8 can include a longitudinal seam 234 where the overlapping portion 220 terminates at the folded portion 218. In use, the sheath 8 can be positioned such that the seam 234 is posterior to the point of the sheath that is 180 degrees from the seam 234 (for example, facing downward in the view of FIG. 21). As shown in FIG. 21, the seam 234 need not extend the entire length of the sheath 8, and end at a transition point between portions of the sheath having a folded inner layer and portions of the sheath not having a folded inner layer.

[0149] In some examples, the folded portion 218 can include a weakened portion 236, such as a longitudinal perforation, score line, and / or slit, along at least a portion of the length of the inner layer 202. The weakened portion 236 / slit allows for the two adjacent ends 238, 240 of the folded portion 218 / inner layer 202 to move relative to one another as the sheath 8 expands to the expanded configuration shown in FIG. 23. For example, the sheath 8 locally expands as a medical device is inserted therethrough, causing the weakened portion 236 to split / separate.

[0150] In each of the example sheaths 8 described herein, the sheath 8 may include an elastic outer layer 250 that expands with the sheath 8. The elastic outer layer 250 can provide an inwardly directed radial force that directs the sheath to a folded / unexpanded configuration. Similar to the strain relief layer 26, elastic outer layer 250 can also provide hemostasis (for example, prevent blood loss during implantation of the prosthetic device).

[0151] The elastic outer layer 250 can be positioned around at least a portion of the strain relief layer 26, outer layer 108, 204 and / or the inner layers of the sheath 8. As illustrated in FIGS. 21-23, the elastic outer layer 250 can surround the entire circumference of outer layer 204, and can extend longitudinally along any portion of the length of the sheath 8, including along (over or under) the strain relief layer 26. The elastic outer layer 250 extends for a length along at least a portion of the main body of the sheath 8. In some examples, the elastic outer layer 250 extends to a point adjacent the distal end 210, or can extend all the way to the distal end 210 of sheath 8. For example, the elastic outer layer 250 extends over the entire length of the sheath 8.

[0152] As shown in FIGS. 17-20, 22 and 23, the elastic outer layer 250 can be a continuous tubular layer, without slits or other discontinuities. The elastic outer layer 250 extends between strain relief layer 26 and the outer surface of the outer layer 204. In some examples, the elastic outer layer 250 extends over the outer surface of the strain relief layer 26 and the outer surface of the outer layer 204. In some examples, the elastic outer layer 250 extends both over the strain relief layer 26 and / or between the outer layer of the sheath 8 and the strain relief layer 26.

[0153] The elastic outer layer 250 can comprise any pliable, elastic material(s) that expand and contract, preferably with a high expansion ratio. Preferably, the materials used can include low durometer polymers with high elasticity, such as Pebax, polyurethane, silicone, and / or polyisoprene. Materials for the elastic outer layer 250 can be selected such that it does not impede expansion of the inner and outer layers of the sheath 8. The elastic outer layer 250 can have a thickness ranging from, for example, about 0.001 inches to about 0.010 inches. In some examples, the elastic outer layer 250 can have a thickness of about 0.003 inches to about 0.006 inches. The elastic outer layer 250 can be configured to stretch and expand as the sheath expands, as shown in the expanded configuration in FIG. 20.

[0154] As illustrated in FIGS. 2, 15, and 21, the sheath 8 in each of the examples described herein may include a strain relief layer 26. The strain relief layer 26 is provided adjacent the proximal end of the sheath 8 and extends along / over the outer surface of the sheath 8. In some examples, the strain relief layer 26 is provided over the outer layer 108, 204 of thesheath 8. The strain relief layer 26 forms a smooth transition between the sheath hub 20 and the sheath 8 and facilitates mating of the sheath 8 with the sheath hub 20.

[0155] Additionally, and as will be described in more detail herein, the strain relief layer 26 provides a region of higher durometer or stiffness that restricts expansion of the underlying sheath layers. This helps to ensure hemostasis between the portions of the sheath 8 inside the patient and the sheath hub (external to the patient). The increased durometer and / or stiffness along the strain relief layer 26 prevents blood from flowing between the various layers of the sheath 8 exterior to the patient during the procedure, helping to withstand the blood pressure that would otherwise cause the sheath to “balloon up” with body fluid / blood. Additionally, the strain relief layer 26 can be sized and configured to form a seal with the patient’s artery when inserted, such that blood is substantially prevented from flowing between the strain relief layer 26 and the vessel wall. For example, although the strain relief layer 26 does not extend all the way to the distal end 210 of the sheath 8, the strain relief layer 26 can extend distally enough along the sheath 8 that when the sheath 8 is fully inserted into the patient a portion of the strain relief layer 26 extends through and seals against the arteriotomy site.

[0156] As described herein, the strain relief layer 26 is provided over the outer layer 108, 204 of the sheath 8. The strain relief layer 26 can be bonded to the outer layer 108, 204 to prevent the strain relief layer 26 from sliding over the outer layer and “bunching up” in response to the friction forces applied by the surrounding tissue during insertion of the sheath 8 into the patient’ s vasculature. For example, the strain relief layer 26 can be bonded at the proximal end and / or distal end of the outer layer 108, 204. At the proximal and distal ends, the strain relief layer 26 can be bonded to the outer layer 204 around the full circumference of the outer layer. At the distal end of the sheath 8, the strain relief layer 26 can additionally and / or alternatively be bonded to the inner layer(s) of the sheath 8. For example, the strain relief layer 26 can be bonded to the distal end surface of the inner layer 102, 202.

[0157] FIGS. 18, 22 and 23 illustrate cross-sectional views of the sheath 8 along the strain relief layer 26. FIG. 18 shows a cross-section of a segment of the sheath near the proximal end 214 of the sheath 8, as indicated by line 18-18 in FIG. 15. Similarly, FIGS. 22 and 23 show cross-section segments of various example sheaths near the proximal end 214 of the sheath 8 and closer to the distal end of the strain relief layer 26, as indicated by section line 22-22 in FIG. 21. As illustrated in each of FIGS. 15-23, the sheath 8 at this location can comprise a liner / inner layer 202, outer layer 204, adhesive material 228, an optional elastic outer layer 250, and the strain relief layer 26.

[0158] The strain relief layer 26 extends circumferentially around at least a portion of the inner layer 202 and outer layer 204. The strain relief layer 26 extends from the proximal end 214 of the sheath 8 towards the distal end 210 of the sheath 8. As shown in FIG. 21 (and FIG. 15), the strain relief layer 26 extends for a length L along at least a portion of the main body of the sheath 8. In some examples, the strain relief layer 26 extends to a point adjacent the distal end 210, or can extend all the way to the distal end 210 of sheath 8. In some examples, the longitudinal length L of the strain relief layer 26 can range from about 10 cm to the entire length of the sheath 8.

[0159] The strain relief layer 26 extends to / adjacent the proximal end 214 of the sheath 8 and provides a compression fit over the distal end of the sheath hub 20 thereby coupling the sheath 8 to the sheath hub 20. Additionally, or alternatively, the strain relief layer 26 secured between the sheath hub 20 and the sheath hub cap 22 or other fastening device for by coupling the proximal end of the sheath to the sheath hub 20. In some examples, the strain relief layer 26 does not extend all the way to the proximal end 214 of the sheath 8.

[0160] It is understood that strain relief layer 26, as shown herein, can have similar composition and characteristics of the inner and outer layers as disclosed herein. Various compositions are disclosed, for example, in Application No. PCT / US2021 / 301275, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” the disclosure of which is herein incorporated by reference.

[0161] The strain relief layer 26 can comprise any lubricious, low-friction, and / or relatively non-elastic material. Preferably the materials used can include high durometer polymers, with low elasticity. In some examples, the strain relief layer 26 is composed of the same and / or similar material to the inner layer 202 and / or outer layer 204. For example, as described herein regarding the inner layer 102 and / or outer layer 108, exemplary materials can include polyurethane (for example, high density polyethylene), ultra-high-molecular-weight polyethylene (UHMWPE) (for example, Dyneema®), high-molecular-weight polyethylene (HMWPE), or poly ether ether ketone (PEEK). Other suitable materials strain relief layer 26 can include poly imide, polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyamide, polyether block amide (for example, Pebax), and / or combinations of any of the herein. Materials for the strain relief layer 26 can be selected such that it impedes expansion of the underlying layers of the sheath 8.

[0162] The strain relief layer 26 can have a thickness ranging from, for example, about 0.001 inches to about 0.010 inches. In some examples, the strain relief layer 26 can have athickness of from about 0.003 inches to about 0.006 inches. The wall thickness is measured radially between the inner surface of the strain relief layer 26 and the outer surface of the strain relief layer 26.

[0163] In some examples, the material composition and / or wall thickness can change along the length of the strain relief layer 26. For example, the strain relief layer 26 can be provided with one or more segments, where the composition and / or thickness changes from segment to segment. In an example aspect, the Durometer rating of the composition changes along the length of the strain relief layer 26 such that segments near the proximal end comprise a stiffer material or combination of materials, while segments near the distal end comprise a softer material or combination of materials. Similarly, the wall thickness of the strain relief layer 26 in segments near the proximal end can be thicker / greater than the wall thickness of the elastic outer layer 250 near the distal end.

[0164] As illustrated in FIGS. 15 and 21, the strain relief layer 26 has a proximal end and a distal end and a central lumen extending longitudinally therethrough. The strain relief layer 26 includes a generally tubular shaped proximal portion 242 adjacent the proximal end of the strain relief layer 26, and a generally tubular shaped distal portion 246 adjacent the distal end of the strain relief layer 26. The strain relief layer 26 includes a frustoconical shaped tapered portion 248 extending between the proximal portion 242 and the distal portion 246 of the strain relief layer 26, such that the diameter of the strain relief layer 26 at the proximal portion 242 is greater than the diameter of the strain relief layer 26 at the distal portion 246 of the strain relief layer 26. The tapered portion 248 and the flared proximal portion 242 help ease the transition of the medical device / delivery apparatus when passing between the larger diameter sheath hub 20 to the smaller diameter of the sheath 8.

[0165] As described herein, the strain relief layer 26 is made of a material that is stiffer than the other sheath 8 layers such that the strain relief layer 26 inhibits expansion of the portion of the sheath disposed along / under the strain relief layer 26. Because radial expansion is limited along the strain relief layer 26, higher push forces are necessary to advance the medical device through the central lumen of the sheath 8. In some examples, the highest push forces through the sheath 8 are experienced near the proximal and distal ends of the sheath 8, through the strain relief layer 26 (for example, through the tapered portion of the strain relief layer 26), and at proximal and distal ends of the strain relief layer 26.

[0166] As described herein, it is desirable to reduce push forces required to insert the medical device / delivery apparatus through the central lumen of the sheath 8. In some examples, the thickness and / or composition of the strain relief layer 26 and / or sheath 8 can beadjusted to improve the performance of the sheath 8 and reduce the push force. In some examples, dilating or expanding the sheath 8 (or a portion thereof) before the medical device / delivery apparatus is introduced helps to reduce the initial push force through the sheath 8. Pre-dilating the sheath 8 releases and / or loosens any bonding or adhesion of the sheath 8 layers that occurs during the manufacturing process, for example, bonding between the inner and outer layers 202, 204, bonding between the folded portion 218 and outer layer 204, bonding between the inner / outer layers and the strain relief layer 26. Pre-dilating can also break or separate the weakened portion 236 of folded portion 218 of the inner layer 202, separating adjacent ends 238, 240 of the folded portion 218, as described herein and illustrated in FIG. 23. With the sheath 8 layers able to move freely with respect to the other, the medical device / delivery apparatus is pushed through the sheath 8 lumen at a much lower force.

[0167] As noted above, introducer sheaths are often designed for use via femoral approach. Accordingly, introducer sheaths typically have a length sufficient to extend from a femoral access site through the femoral artery and into the abdominal aorta. However, this configuration is not well-suited for alternative approaches (such as carotid, subclavian, and axillary approaches). FIG. 24 shows introducer sheaths introduced at the femoral access site SF, the carotid access site Sc, the axillary access site SA, and the subclavian access site Ss. When these long sheaths are inserted at positions near the heart via alternative approaches, excess length of the introducer sheath is left dangling outside of the patient’s body, as shown in FIG. 24. This can produce stress at the access point, leading to sheath kinking and overall poor usability. Furthermore, portions of the sheath that extend outside of the patient’s body may not be suitable to resist radially outward pressures. Rather, high enough pressures within the sheath can cause portions of the sheath that extend outside the patient to “balloon”, which can lead to bursting of one or more layers of the introducer sheath and subsequent blood loss.

[0168] Thus, it is desirable to be able to adjust the length of the sheath from an initial sheath length LI to a reduced length, therefore reducing the portion of the sheath that remains outside the patient’s body. However, attempts to adjust the length of the sheath may encounter various obstacles. For example, the distal ends of various sheaths can comprise specialized features which may be lost if the length of the sheath were reduced by severing the sheath and discarding the distal end. Furthermore, where a sheath is severed, portions of the sheath on either side of the cut can have rough edges or shed particulates of the sheath.

[0169] Various devices and methods for stabilizing sheath systems 300, 400, and 500 are disclosed herein with reference to FIGS. 25-32. These sheath systems and methods facilitatesetting / adjusting the length of a sheath to reduce the length of the sheath that extends outside of the patient while avoiding these problems. It is contemplated herein that the sheath systems 300, 400, and 500 can be used individually and / or with other components described herein in reference to FIGS. 1-23, such as the delivery apparatus 10 or the prosthetic device 12. Additionally, it is contemplated that the sheath systems 300 can be formed and used individually and / or be integrated into another expandable sheath, including the sheath 8 as described herein or sheaths having different layered sheath structures than those described herein.

[0170] Furthermore, it is contemplated that the sheaths 308 provided herein can have any of the attributes provided above with respect to sheath 8. For example, the sheaths 308 can include a continuous inner layer and one or more additional layers disposed radially outward of the inner layer, such as a second layer, a third layer (also referred to as an elastic layer), and / or a fourth layer (also referred to as an outer layer). As described herein with respect to sheath 8, the sheath 308 can include at least one folded portion extending along a length of the inner layer. As an outwardly directed radial force is applied from within the sheath 308, the folded portion can at least partially separate, straighten, and / or unfold, thereby allowing a diameter of a central lumen 312 of the sheath 308 to enlarge. In this manner, the sheath 308 is configured to radially expand from a resting / unexpanded configuration to an expanded configuration.

[0171] In some aspects, the present disclosure provides various methods for setting the length of the sheath 308 that include severing / cutting the sheath 308, thereby dividing the sheath 308 into one or more sections. As used herein, the terms “initial distal end” and “initial proximal end” correspond to the distal end 310 and the proximal end 314 of the sheath 308 before it is cut. After the sheath 308 is cut, one or more ends of the one or more sections of the sheath 308 will be newly formed. Newly formed ends of the sheath 308 created by the act of cutting the sheath 308 are herein referred to as “second” or “third” ends.

[0172] While this disclosure is described in the context of alternative vascular approaches (such as but not limited to the carotid, subclavian, and axillary approaches), similar devices, systems, and methods could be utilized with the femoral approach, according to physician discretion (for example, with smaller patients, during pediatric procedures, or during veterinary procedures).

[0173] FIG. 25 illustrates side views of an example introducer sheath system 300 including an example sheath 308 that has an initial distal end 310 and an initial proximal end 314 and defines a central lumen 312 extending therebetween along the longitudinal axis X. As shown,the sheath 308 has an initial sheath length LI, which corresponds to the distance between the initial distal end 310 and the initial proximal end 314 of the sheath 308.

[0174] The illustrated introducer sheath system 300 includes an initial sheath hub 340. The initial sheath hub 340 has a hub body 342 extending between a proximal end 344 and a distal end 346 of the initial sheath hub 340 and defines a central lumen 348 extending longitudinally therethrough. It is contemplated that the initial sheath hub 340 provided herein can have any of the attributes provided above with respect to the sheath hub 20. As shown, the distal end 346 of the initial sheath hub 340 is coupled to the initial proximal end 314 of the sheath 308.

[0175] FIG. 25 provides a method for setting the length of the sheath 308 in the introducer sheath system 300. The method includes cutting the sheath 308 at a cut location 316 that is between the initial distal end 310 and the initial proximal end 314. As illustrated in FIG. 25, cutting the sheath 308 at cut location 316 divides the sheath 308 into a first section 302 and a second section 304. The first section 302 corresponds to a portion of the sheath 308 distal to the cut location 316 and the second section 304 corresponds to a portion of the sheath 308 proximal to the cut location 316. Accordingly, the first section 302 extends between the initial distal end 310 and a second proximal end 314’ formed directly distal of the cut location 316. A distance between the initial distal end 310 and a second proximal end 314’ defines a first section length L2 of the first section 302. Conversely, the second section 304 extends between a second distal end 310’ formed directly proximate of the cut location 316 and the initial proximal end 314.

[0176] As shown in FIG. 25, once the first section 302 is formed by the cut, a second sheath hub 340’ is introduced. Accordingly, the method further includes coupling the second sheath hub 340’ to the first section 302. Specifically, the distal end 346’ of the second sheath hub 340’ is coupled to the second proximal end 314’ of the first section 302. As shown, a second lumen 348’ of the second sheath hub 340’ is aligned with the central lumen 312 of the sheath 308 to facilitate passage of the delivery apparatus 10 / medical device 12 therethrough. Advantageously, this method of setting the length of the sheath 308 facilitates reducing the length of the sheath 308 while conserving the initial distal end 310.

[0177] In the illustrated example, the second sheath hub 340’ has all the attributes of the initial sheath hub 340. In further examples, the second sheath hub 340’ can be configured differently from the initial sheath hub 340, so long as the second sheath hub 340’ is couplable to the second proximal end 314’ of the first section 302 of the sheath 308.

[0178] In some examples, the first section length L2 is based on a length of the sheath 308 to be inserted into the patient’s vasculature Lmsertion, which is defined by the distance between the incision site and the treatment site. This is to ensure that position of the cut location 316 along the sheath 308 yields a first section 302 having a first section length L2 that is at least the required insertion length Lmsertion. Accordingly, the axial position of the cut location 316 can be selected anywhere along the sheath 308 such that the first section length L2 is equal to or greater than the insertion length Linsertion. In some examples, the first section length L2 can optionally he approximately the same as insertion length Li,lsertion so as to reduce the portion of the sheath 308 extending outside of the patient’s body during the procedure. As provided herein, the desired insertion length Lmsertion and corresponding first section length L2 can vary depending on patient size and anatomy, as well as physician preferences.

[0179] In some examples, cutting the sheath 308 includes cutting the sheath 308 at a cut angle relative to the longitudinal axis X of the sheath 308. Specifically, FIG. 25 shows the sheath 308 cut a 90° angle relative to the longitudinal axis X of the sheath 308. However, in further examples, the sheath 308 can be cut at various angles relative to the longitudinal axis X of the sheath so long as the second proximal end 314’ of the first section 302 of the sheath 308 remains couplable to the second sheath hub 340’. For example, the sheath 308 can be cut at an angle of 90° to 135° relative to the longitudinal axis X. In some examples, the sheath 308 can be cut at an angle of 90° to 105° relative to the longitudinal axis X. In some examples, the sheath 308 can be cut at an angle of 90° to 95° relative to the longitudinal axis X. Advantageously, cutting the sheath 308 at an angle at or near 90° facilitates easier coupling with the second sheath hub 340’.

[0180] As provided herein, the sheath 308 is configured to facilitate passage of the delivery apparatus 10 / medical device 12 through an incision site and to a treatment site within a patient’s body. In some examples, it is contemplated that the insertion length Lmsertion, and accordingly, the desired first section length L2 (as determined by the cut location 316) is determined before any portion of the sheath 308 is inserted into the incision site. This allows the sheath 308 to be cut away from the patient’s body. Once the sheath 308 is cut and the second sheath hub 340’ is coupled to the first section 302 of the sheath 308, the sheath 308 can be inserted at least partially into a blood vessel at the incision site and advanced toward the treatment site.

[0181] As provided herein, when a medical device 12, such as a prosthetic heart valve, is advanced through the central lumen 312 of the sheath 308, the medical device 12 exerts an outwardly directed radial force against an inner layer of the sheath 308. This causes thesheath 308 to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device 12. As provided herein, an inner layer of the sheath 308 can include at least one folded portion. Locally expanding the central lumen 312 of the sheath 308 causes a length of the folded portion to at least partially unfold. As the medical device 12 passes through the central lumen 312, the sheath 308 locally contracts at least partially back to the unexpanded configuration. Finally, the medical device 12 can be advanced beyond a distal opening at the initial distal end 310 of the sheath 308 and toward the treatment site.

[0182] In some examples, the dilator 6 (also referred as an introducer) as described herein is advanced into the central lumen 312 of the sheath 308 through the lumen 348’ of the second sheath hub 340’. In these examples, the sheath 308 can be inserted at least partially into a blood vessel at the insertion site with the dilator 6 disposed within the sheath 308. The rigidity of the dilator 6 helps to expand the patient’s blood vessel. Once the sheath 308 is positioned, the dilator 6 can be withdrawn from the central lumen 312 of the sheath 308 and the delivery apparatus 10 can be introduced.

[0183] The medical device 12 described herein can include a prosthetic device mounted in a radially crimped state on the delivery apparatus 10, and the act of advancing the prosthetic device through the central lumen 312 of the sheath 308 can comprise advancing the delivery apparatus 10 and the prosthetic device through central lumen 312 of the sheath 308 and into the vasculature of the patient. In some examples, the prosthetic device comprises a prosthetic heart valve and the method further comprises implanting the prosthetic heart valve at the treatment site within the patient. In some examples, the prosthetic heart valve is mounted on a balloon catheter of the delivery apparatus 10 as the prosthetic heart valve is advanced through the sheath 308.

[0184] In some instances, it may be desirable to adjust the length of the sheath 308 while conserving both the initial distal end 310 and the initial sheath hub 340 (hereafter referred to as simply the “sheath hub 340”). One possible solution is to cut the sheath 308 at two axial cut locations spaced apart from one another along the length of the sheath 308 and disposing of a central section of the sheath defined between the two cut locations. However, an obstacle arises based on the need to recouple the section of the sheath 308 comprising the initial distal end 310 to the sheath hub 340.

[0185] FIGS. 26-29B refer to an example sheath coupling system 400 including a sheath 308, a sheath hub 340 disposed proximal to the sheath 308, and an initial hub cap 320 coupled to the sheath hub 340. As shown in FIG. 26, the sheath coupling system 400 furtherincludes a hub coupler 360 for coupling the sheath 308 to a second hub cap 320’ after the length of the sheath 308 has been adjusted, thereby recouping the sheath 308 to the sheath hub 340. Advantageously, the hub coupler 360 facilitates the removal of an intermediate length of sheath 308, (for example, second section 304 of sheath 308, as shown in FIG. 29A- 29B) and the subsequent recoupling of first section 302 to sheath hub 340 via third proximal end 314” and other components to be described below. In this way, both the initial distal end 310 and the initial sheath hub 340 are preserved. Since the distal end 310 and the sheath hub 340 often have specialized components and manufacturing processes, this preservation can reduce costs.

[0186] It is contemplated that the example sheath 308 illustrated in FIGS. 26 and 27 can have any of the attributes of the example sheath 308 provided above with respect to FIG. 25. Accordingly, the sheath 308 has an initial sheath length LI, which corresponds to the distance between the initial distal end 310 and the initial proximal end 314 of the sheath 308.Similarly, it is contemplated that the sheath hub 340 illustrated in FIGS. 26 and 27 can have any of the attributes of the sheath hub 340 provided above with respect to FIG. 25.

[0187] Furthermore, as shown in FIGS. 26 and 27, the sheath coupling system 400 also includes an initial hub cap 320 for securing the sheath 308 to the sheath hub 340 prior to setting the length of the sheath 308. It is contemplated that the initial hub cap 320 can have any of the attributes of the hub cap 22 provided above with respect to FIGS. 2-6.Accordingly, as shown in FIG. 27, the initial hub cap 320 includes a proximal end 324 and a distal end 326 and defines a lumen extending longitudinally therethrough. As shown, the initial hub cap 320 receives the distal end 346 of the sheath hub 340, thereby coupling the initial hub cap 320 to the sheath hub 340. Specifically, as shown in FIG. 27, the initial hub cap 320 comprises a radially inwardly extending threaded region 330 defined adjacent the proximal end 324 of the initial hub cap 320. This threaded region 330 threadingly engages a complementary radially outwardly extending threaded region defined adjacent the distal end 346 of the sheath hub 340. As described herein, the initial proximal end 314 of the sheath 308 is positioned between the distal end 326 of the initial hub cap 320 and the distal end 346 of the sheath hub 340 such that coupling the initial hub cap 320 to the sheath hub 340 fixes the sheath 308 to the initial hub cap 320 and to the sheath hub 340.

[0188] As shown in FIGS. 26-28, the sheath coupling system 400 includes a hub coupler 360 that has a body 362 extending between a proximal end 364 and a distal end 366 and defining a lumen 368 extending longitudinally therethrough. As shown in FIGS. 27 and 28, the proximal end 364 of the hub coupler 360 has a diameter that is radially expanded relativeto a diameter of the distal end 366. As shown, the proximal end 364 of the hub coupler 360 is configured to receive the distal end 366 of the initial hub cap 320. Accordingly, an inner surface 370 of the hub coupler body 362 has a profile that complements an outer surface of the initial hub cap 320. Furthermore, in order to promote mechanical coupling between the hub coupler 360 and the initial hub cap 320, the hub coupler 360 further includes a tab 372 extending radially inward from the hub coupler body 362. As shown in FIG. 27, the tab 372 is configured to couple with a gap 350 formed between the sheath hub 340 and the proximal end 324 of the initial hub cap 320. In the illustrated example, the tab 372 extends circumferentially about the proximal end 364 of the hub coupler 360. Furthermore, as shown in FIG. 27 and further described herein, the distal end 366 of the hub coupler 360 comprises a radially outwardly extending threaded region 374 defined adjacent the distal end 366 of the hub coupler 360.

[0189] Additionally, as shown in FIGS. 26 and 27, the sheath coupling system 400 includes a second hub cap 320’ for securing the sheath 308 to the sheath hub 340 after adjusting the length of the sheath 308. It is contemplated that the second hub cap 320’ can have any of the attributes of the initial hub cap 320. Accordingly, as shown in FIG. 27, the second hub cap 320’ includes a proximal end 324’ and a distal end 326’ and defines a lumen extending longitudinally therethrough.

[0190] As shown in FIGS. 26 and 27, second hub cap 320’ is disposed distal to the initial hub cap 320. In the illustrated example, the second hub cap 320’ is configured to receive the distal end 366 of the hub coupler 360, thereby coupling the second hub cap 320’ and the hub coupler 360. Specifically, as shown in FIG. 27, the second hub cap 320’ comprises a radially inwardly extending threaded region 330’ defined adjacent the proximal end 324’ of the second hub cap 320’. This threaded region 330’ threadingly engages the complementary radially outwardly extending threaded region 374 defined adjacent the distal end 366 of the hub coupler 360. In some examples (as shown in FIGS. 27 and 29B), a coupler seal 390 can be disposed between the distal end 366 of the hub coupler 360 and the threaded region 330’ of the second hub cap 320’, thereby reducing the risk of fluid leaking between the coupling. In the example illustrated in FIG. 27, the coupler seal 390 is formed as rubber O-ring and extends around the distal end 366 of the hub coupler 360 adjacent a distal end of the threaded region 330’. In some examples, the coupler seal 390 can be formed as a sleeve that extends over the distal end 366 of the hub coupler 360 and around a portion of the sheath 308 (for example, the first section 302). Furthermore, the coupler seal 390 can be formed from anycompliant material that is capable of reducing fluid leakage between the coupling formed between the hub coupler 360 and the second hub cap 320’, such as silicone.

[0191] As described herein, the initial proximal end 314 of the sheath is positioned between the distal end 326 of the initial hub cap 320 and the distal end 346 of the sheath hub 340 such that coupling the initial hub cap 320 to the sheath hub 340 fixes the sheath 308 to the initial hub cap 320 and to the sheath hub 340. However, as described further herein, adjusting the length of the sheath 308 forms a section of the sheath 308 having a newly formed proximal end (for example, the third proximal end 314” as described further herein). As provided herein and shown in FIG. 27, the newly formed third proximal end 314” of the sheath 308 is positioned between the distal end 326’ of the second hub cap 320’ and the distal end 366 of the hub coupler 360 such that coupling the second hub cap 320’ to the hub coupler 360 fixes the length-adjusted sheath 308 to the hub coupler 360 and to the sheath hub 340. In this way, the distal end 366 of the hub coupler 360 can serve as a functional substitute for the distal end 346 of the sheath hub 340 that is already coupled to the initial hub cap 320. Advantageously, this configuration facilitates coupling a length-adjusted sheath having a newly formed proximal end (for example, the third proximal end 314”) to the same sheath hub 340 that was (and possibly remains) coupled to the initial proximal end 314 of the sheath 308.

[0192] In the example illustrated in FIG. 27, the initial hub cap 320 is directly coupled to the sheath hub 340 by engagement of complementary threading; the proximal end 364 of hub coupler 360 is directly coupled to the initial hub cap 320 and sheath hub 340 by a snap fit; and the second hub cap 320’ is directly coupled to the distal end 366 of the hub coupler by engagement of complementary threading. In further examples, the hub coupler 360 may be directly or indirectly coupled to any one of the proximal end 314 of the sheath 308, the hub cap 320, and / or the sheath hub 340 by at least one of a press fit, an interference fit, a snap fit, a mechanical fastener, a weld and / or an adhesive.

[0193] In various examples, an inner diameter of the sheath 308 gradually tapers from the initial proximal end 314 to the initial distal end 310. Accordingly, adjusting the length of the sheath 308 by cutting the sheath 308 to form a section of sheath 308 having a reduced length also forms new ends of the sheath having an inner diameter that varies based on the axial location of the cut. In some instances, the newly formed proximal end of the sheath 308 (such as the third proximal end 314’ ’) thus has an inner diameter that is smaller than a diameter of the initial proximal end 314 of the sheath 308 prior to cutting.

[0194] In some examples, the sheath coupling system 400 can optionally include an adapter 380. As shown, in FIG. 28, the adapter 380 includes a body 382 having a proximal end 384and a distal end 386 and defining a lumen 388 extending longitudinally therethrough. As shown, the adapter 380 tapers from the proximal end 384 toward the distal end 386. Specifically, the proximal end 384 has a first adapter diameter DAI and the distal end 366 has a second adapter diameter DA2 that is less than the first adapter diameter DAI.

[0195] The example adapter 380 illustrated in FIG. 28 is shown coupled to the distal end 366 of the hub coupler 360. Accordingly, the proximal end 384 of the adapter 380 is sized and configured to receive the distal end 366 of the hub coupler 360 and the distal end 386 of the adapter 380 is sized and configured to be received within a proximal end of the sheath 308 (such as the third proximal end 314”). Advantageously, the adapter 380 thus accounts for a decreased inner diameter of the newly formed proximal end of the sheath 308 (such as the third proximal end 314”) relative to the inner diameter of the initial distal end 310 of the sheath 308.

[0196] In further examples, the adapter 380 can be used to couple alternate sheaths to the sheath hub 340. For example, where a sheath having a smaller inner diameter is desirable for a particular procedure, the adapter 380 can facilitate coupling of the smaller inner diameter sheath to the sheath hub 340.

[0197] Returning now to FIG. 26, an example adapter 380 is shown coupled to the second hub cap 320’. Accordingly, in this example, the adapter 380 is sized and configured to receive the distal end 326’ of the second hub cap 320’ and is sized and configured to be received within a proximal end of the sheath 308 (such as the third proximal end 314”). Advantageously, the adapter 380 thus accounts for a decreased inner diameter of the newly formed proximal end of the sheath 308 (such as the third proximal end 314”) relative to the inner diameter of the initial distal end 310 of the sheath 308 where the decrease in inner diameter prevents the newly formed proximal end of the sheath 308 from being positioned between the distal end 326’ of the second hub cap 320’ and the distal end 366 of the hub coupler 360.

[0198] Referring now to FIGS. 29A-29B, a method for setting the length of the sheath 308 in the introducer sheath system 300 is provided. As shown in FIG. 29A, the method includes cutting the sheath 308 at a first cut location 317 that is between the initial distal end 310 and the initial proximal end 314 and cutting the sheath 308 at a second cut location 318 that is between the first cut location 317 and the initial distal end 310. As illustrated in FIG. 29A, cutting the sheath 308 at the first cut location 317 and the second cut location 318 divides the sheath 308 into a first section 302, a second section 304, and a third section 306.

[0199] As illustrated in FIG. 29A, the first cut location 317 forms a second distal end 310’ and a second proximal end 314’ on either side of the first cut location 317 and at least temporarily uncouples a portion of the sheath 308 from the sheath hub 340. As shown, the third section 306 extends between the initial proximal end 314 and the second distal end 310’. A distance between the initial proximal end 314 and the second distal end 310’ defines a third section length L4. In some examples, the first cut location 317 is selected to be axially adjacent the distal end 326 of the initial hub cap 320. Advantageously, this reduces the residual length L4 of the third section 306 that remains after the cut.

[0200] FIG. 29A also shows that the second cut location 318 forms a third distal end 310’ ’ and a third proximal end 314” on either side of the second cut location 318. The second section 304 extends between the second proximal end 314’ and the third distal end 310”. A distance between the second proximal end 314’ and the third distal end 310’ ’ defines a second section length L3.

[0201] As further shown in FIG. 29A, the first section 302 corresponds to a portion of the sheath extending between the third proximal end 314” and the initial distal end 310. A distance between the third proximal end 314” and the initial distal end 310 defines a first section length L2.

[0202] In other words, the first section 302 corresponds to a portion of the sheath 308 distal to the second cut location 318, the second section 304 corresponds to a portion of the sheath 308 between the first cut location 317 and the second cut location 318, and the third section 306 corresponds to a portion of the sheath 308 proximal to the first cut location 317.

[0203] In some examples, cutting the sheath 308 at the first cut location 317 and / or the second cut location 318 includes cutting the sheath 308 at first and second cut angles, respectively, relative to the longitudinal axis X of the sheath 308. Specifically, FIG. 29A shows the sheath 308 cut at 90° angles relative to the longitudinal axis X of the sheath 308. However, in further examples, the sheath 308 can be cut at various first and second cut angles relative to the longitudinal axis X of the sheath so long as the third proximal end 314” of the first section 302 and the second distal end 310’ of the third section 306 remain couplable to the hub coupler 360. For example, the sheath 308 can be cut at first and / or second cut angles of 90° to 135° relative to the longitudinal axis X. In some examples, the sheath 308 can be cut at first and / or second cut angles of 90° to 105° relative to the longitudinal axis X. In some examples, the sheath 308 can be cut at first and / or second cut angles of 90° to 95° relative to the longitudinal axis X. Advantageously, cutting the sheath 308 at first and / or second cut angles at or near 90° facilitates easier coupling with the hub coupler 360.

[0204] In some examples, the first section length L2 is based on a length of the sheath 308 to be inserted into the patient’s vasculature Lmsertion, which is defined by the distance between the incision site and the treatment site. This is to ensure that position of the second cut location 318 along the sheath 308 yields a first section 302 having a first section length L2 that is at least the required insertion length Lmsertion. Accordingly, the axial position of the second cut location 318 can be selected anywhere along the sheath 308 such that a combined length of the first section length L2 and the third section length L4 is equal to or greater than the insertion length Lmsertion. In some examples, the combined length of the first section length L2 and the third section length L4 can optionally be approximately the same as insertion length Lmsertion so as to reduce the portion of the sheath 308 extending outside of the patient’s body during the procedure. As provided herein, the desired insertion length Linsertion and corresponding combined first section length L2 and third section length L4 can vary depending on patient size and anatomy, as well as physician preferences. Furthermore, in some examples, additional cuts can be made to the sheath 308 so as to obtain the desired first section length L2 and / or third section length L4. Once the first section 302 and / or third section 306 has been cut to a desired first section length L2 and / or third section length L4, the second section 304 can be discarded.

[0205] As illustrated in FIG. 29B, the hub coupler 360 can be used to couple the first section 302 to the sheath hub 340. Specifically, as shown in FIG. 29B, the proximal end 364 of the hub coupler 360 is coupled to the distal end 346 of sheath hub 340 and the initial hub cap 320. In some examples, coupling the proximal end 364 of the hub coupler 360 to the sheath hub 340 includes coupling the tab 372 into the gap 350 formed between the sheath hub 340 and the proximal end 324 of the initial hub cap 320 (as shown in cross section at FIG. 27).

[0206] As shown in FIG. 29B, once the first section 302 of the sheath 308 is coupled to the hub coupler 360 (optionally with the assistance of coupler seal 390), a second hub cap 320’ is then coupled to the hub coupler 360. This includes passing the second hub cap 320’ over the sheath 308 and moving the second hub cap 320’ proximally along the sheath 308 toward the distal end 366 of the hub coupler 360 until the proximal end 324’ of the second hub cap 320’ engages with the distal end 366 of the hub coupler 360. Specifically, the radially inwardly extending threaded region 330’ of the second hub cap 320’ is threadingly engaged with the radially outwardly extending threaded region 374 of the hub coupler 360. Accordingly, the third proximal end 314” of the sheath 308 is positioned between the distal end 326’ of the second hub cap 320’ and the distal end 366 of the hub coupler 360 such that coupling thesecond hub cap 320’ to the hub coupler 360 fixes the length-adjusted sheath 308 to the hub coupler 360 and to the sheath hub 340.

[0207] In some examples, including the example shown in FIG. 29B, a coupler seal 390 can be disposed between the distal end 366 of the hub coupler 360 and the threaded region 330’ of the second hub cap 320’, thereby reducing the risk of fluid leaking between the coupling.

[0208] As shown in FIG. 29B, the third proximal end 314’ ’ of the first section 302 of the sheath 308 is coupled to the distal end 366 of the hub coupler 360. In the illustrated example, the first section 302 is held to the hub coupler 360 via an interference fit by inserting the distal end 366 of the hub coupler 360 into the proximal end 314’ ’ of the first section 302. In further examples, the first section 302 of the sheath 308 can be held to the distal end 366 of the hub coupler 360 using a press fit, a weld, and / or an adhesive. It is contemplated that the first section 302 can be coupled to the hub coupler 360 either before or after the hub coupler 360 is coupled to the sheath hub 340. In some examples, the adapter 380 can be used to accommodate a reduction in the inner diameter of the first section 302. For example, the proximal end 384 of the adapter can be coupled to the distal end 366 of the hub coupler 360 and the distal end 386 of the adapter 380 can be coupled to the third proximal end 314” of the sheath 308.

[0209] As shown in FIG. 29B, coupling the first section 302 of the sheath 308 with the sheath hub 340 via the hub coupler 360 aligns the lumen 348 of the sheath hub 340 with the central lumen 312 of the first section 302 of the sheath 308 to facilitate passage of the delivery apparatus 10 / medical device 12 therethrough. Advantageously, this method of setting the length of the sheath 308 facilitates reducing the length of the sheath 308 while conserving both the initial distal end 310 of the sheath 308 and retaining the initial sheath hub 340.

[0210] As provided herein, the sheath 308 is configured to facilitate passage of the delivery apparatus 10 / medical device 12 through an incision site and to a treatment site within a patient’s body. In some examples, it is contemplated that the insertion length Lmsertion, and accordingly, the desired combined first section length L2 and third section length L4 (as determined by the first cut location 317 and the second cut location 318) are determined before any portion of the sheath 308 is inserted into the incision site. This allows one or both of the first cut and second cut of the sheath 308 to be performed away from the patient’s body. Once the sheath 308 is cut at the first cut location 317 and the second cut location 318, the hub coupler 360 is coupled to the sheath hub 340 and the first section 302 of the sheath 308 is coupled to the hub coupler 360, as provided herein. Once the first section 302 of thesheath 308 is coupled to the sheath hub 340 via the hub coupler 360, the sheath 308 can be inserted at least partially into a blood vessel at the incision site and advanced toward the treatment site.

[0211] In some instances, where the initial distal end 310 of the sheath 308 can be discarded, the portion of the sheath 308 that serves as the substitute distal end (also referred to herein after as the second distal end 310’) may have rough edges and / or shed particulates of the sheath 308. Problematically, rough edges at the second distal end 310’ of the sheath 308 may make insertion of the sheath 308 into the incision site more challenging and, if successfully inserted into the patient’s blood vessel, may induce trauma along the walls of the blood vessels while passing therethrough.

[0212] FIGS. 30-32 refer to an example introducer sheath system 500 including a sheath 308, an introducer locking hub 450, and an introducer 420 coupled to the introducer locking hub 450 and received within the sheath 308. As provided herein, a portion of the introducer 420 is configured to enclose a distal end (for example, the second distal end 310’) of the sheath 308. Advantageously, the introducer 420 reduces the risk that rough edges and / or particulates of the sheath 308 interfere with insertion of the sheath 308 into a patient’s blood vessels or cause trauma to the walls thereof while passing therethrough.

[0213] It is contemplated that the example sheath 308 illustrated in FIGS. 30 and 32 can have any of the attributes of the example sheath 308 provided above with respect to FIGS. 25-29B.

[0214] Accordingly, the sheath 308 has an initial sheath length LI, which corresponds to the distance between the initial distal end 310 and the initial proximal end 314 of the sheath 308. As described further herein, some examples of the introducer sheath system 500 further include a sheath hub 340. It is contemplated that the sheath hub 340 illustrated in FIGS. 30 and 32 can have any of the attributes of the sheath hub 340 provided above with respect to FIGS. 25-29B.

[0215] As shown in FIGS. 30-32, the introducer locking hub 450 a proximal end 454 and a distal end 456 and defines a central lumen 458 extending longitudinally between the proximal end 454 and the distal end 456. As shown in FIGS. 30-32, the distal end 456 of the introducer locking hub 450 includes means of engaging the proximal end 344 of the sheath hub 340, thereby coupling the introducer locking hub 450 to the sheath 308 such that an axial position of the introducer locking hub 450 relative to the sheath hub 340 is fixed. Insertion of the introducer locking hub 450 into the sheath hub 340 and sheath 308 aligns the centrallumen 458 of the introducer locking hub 450 with the central lumen 348 of the sheath hub 340 and the central lumen 312 of the sheath 308.

[0216] Furthermore, FIGS. 30-32 show an example introducer 420 coupled to the introducer locking hub 450. As illustrated in FIGS. 30-32, the introducer 420 is segmented into a proximal piece 424 and a separate distal piece 426 spaced axially from the proximal piece 424 along the longitudinal axis X. As shown in FIG. 30, the proximal piece 424 includes a proximal end 440 and a distal end 442, and the distal piece 426 includes a proximal end 430 and a distal end 432. FIG. 31 shows a cross-sectional view of the introducer 420. As shown, the distal piece 426 has a tapered region 434 having an inner surface that widens toward a proximal end 430 of the distal piece 426. In other words, the tapered region 434 refers to a surface of the proximal end 430 that tapers radially inward toward the distal end 432 of the distal piece 426. FIG. 31 also shows that the proximal piece 424 has a tapered region 444 having an outer surface that is complementary to the inner surface of the tapered region 434 of the distal piece 426. As shown, the outer surface of the tapered region 444 narrows toward the distal end 442 of the proximal piece 424. In other words, the tapered region 444 refers to a surface that tapers radially inward toward the distal end 442.

[0217] In some examples, including the example illustrated in FIGS. 30-32, the introducer 420 defines a central lumen 428 extending longitudinally therethrough. Specifically, as shown in FIG. 31, the central lumen 428 is divided between the proximal piece 424 and the distal piece 426. Accordingly, as shown in FIG. 31 , the proximal piece 424 defines a central lumen 476 corresponding to the portion of the central lumen 428 extending therethrough, and the distal piece 426 defines a central lumen 474 corresponding to the portion of the central lumen 428 extending therethrough.

[0218] As shown in FIGS. 30 and 31, the example introducer 420 further comprises an optional hypotube 470 disposed within the central lumen 428 (for example, within the central lumen 474 and central lumen 428) of the introducer 420. As shown in FIG. 31, the hypotube 470 has a proximal end 472 and a distal end 475 and defines a central lumen 476 extending longitudinally between the proximal end 472 and the distal end 475. In some examples, including the illustrated example, the distal end 475 of the hypotube 470 is coupled to the distal piece 426 of the introducer 420 and is slidably disposed within the central lumen 474 of the proximal piece 424 such that axial movement of the hypo tube 470 within the central lumen 476 of the proximal piece 424 causes the distal piece 426 to move axially relative to the proximal piece 424. This coupling can be formed by at least one of a press fit, aninterference fit, a snap fit, a mechanical fastener, a chemical fastener (for example, an adhesive), a weld, a thermal process, and / or any other suitable coupling process known in the art, so long axial movement of the hypotube 470 causes corresponding axial movement of the distal piece 426.

[0219] Accordingly, advancement of the hypotube 470 axially in a distal direction causes the distal piece 426 to move from a first position to a second position distal to the first position, and axial movement of the hypotube 470 in a proximal direction causes the distal piece 426 to move from the second position to the first position.

[0220] FIG. 32 is a side view of the introducer sheath system of FIG. 30, where the introducer 420 is inserted into a length-adjusted sheath 308 (via a sheath hub 340). When coupled to the introducer locking hub 450, the introducer 420 extends beyond the distal end 310’. Furthermore, when the introducer locking hub 450 is coupled to the sheath 308, the introducer 420 is received within the central lumen 312 of the sheath 308 such that the central lumen 428 of the introducer 420 is aligned with the central lumen 312 of the sheath 308, the central lumen 348 of the sheath hub 340, and the central lumen 458 of the introducer locking hub 450.

[0221] In another aspect, FIGS. 30-32 provide a method for setting the length of the sheath 308 in the introducer sheath system 300. As shown in FIG. 30, the method includes cutting the sheath 308 at a cut location 319 that is between the initial distal end 310 and the initial proximal end 314. As illustrated in FIG. 30, cutting the sheath 308 at cut location 319 divides the sheath 308 into a first section 302 and a second section 304. The first section 302 corresponds to a portion of the sheath 308 distal to the cut location 319 and the second section 304 corresponds to a portion of the sheath 308 proximal to the cut location 319. Accordingly, the first section 302 extends between the initial distal end 310 and a second proximal end 314’ formed directly distal of the cut location 319. A distance between the initial distal end 310 and a second proximal end 314’ defines a first section length L2 of the first section 302. Conversely, the second section 304 extends between a second distal end 310’ formed directly proximate of the cut location 319 and the initial proximal end 314. A distance between the second distal end 310’ and the initial proximal end 314 defines a second section length L3 of the second section 304. As shown in FIG. 30, once the first section 302 is formed by the cut, the first section 302 can be discarded.

[0222] Accordingly, the method involves adjusting the length of the sheath 308 such that the second section length L3 corresponds to a desired sheath length. In some examples, the second section length L3 is based on a length of the sheath 308 to be inserted into thepatient’s vasculature Linsertion, which is defined by the distance between the incision site and the treatment site. This is to ensure that the position of the cut location 319 along the sheath 308 yields a second section 304 having a second section length L3 that is at least the required insertion length Linsertion. Accordingly, the axial position of the cut location 319 can be selected anywhere along the sheath 308 such that the second section length L3 is equal to or greater than the insertion length Linsertion- In some examples, the second section length L3 can optionally be approximately the same as insertion length Linsertion so as to reduce the portion of the sheath 308 extending outside of the patient’s body during the procedure. As provided herein, the desired insertion length Linsertion and corresponding second section length L3 can vary depending on patient size and anatomy, as well as physician preferences.

[0223] Once the sheath 308 is cut and the second section 304 has the desired length, the introducer 420 can be inserted into the sheath 308 and the introducer locking hub 450 can be coupled to the sheath hub 340 (and therefore to the second section 304 of the sheath 308).

[0224] As shown in the inset at FIG. 32, the method includes providing the second distal end 310’ of the second section 304 of the sheath 308 between the proximal piece 424 of the introducer 420 and the distal piece 426 of the introducer, thereby enclosing the second distal end 310’ between the two pieces and preventing the second distal end 310’ from extending radially outward beyond the outer diameter GDI of the distal piece 426. Advantageously, this method of setting the length of the sheath 308 facilitates reducing the length of the sheath 308 while preventing any rough edges or particulates at the second distal end 310’ of the sheath 308 from interfering with insertion of the sheath 308 into the blood vessel of a patient or causing trauma along the walls thereof.

[0225] In some examples, providing the second distal end 310’ between the proximal piece 424 of the introducer 420 and the distal piece 426 of the introducer 420 is achieved by axially moving the distal piece 426 relative to the first piece. For example, the distal piece 426 can be moved from the first position adjacent the proximal piece 424 to a second position axially spaced from the proximal piece 424 in a distal direction. The method can also include positioning the second distal end 310’ within the tapered region 434 of the distal piece 426. When the distal piece 426 is moved distally into the second position, this can include positioning the second distal end 310’ longitudinally between the distal piece 426 and the proximal piece 424. The method can further include moving the distal piece 426 proximally from the second position to the first position adjacent the proximal piece 424. In this way, the second distal end 310’ can be enclosed between the proximal piece 424 of the introducer 420 and the distal piece 426 of the introducer 420 such that the distal end 310’ is heldlongitudinally therebetween and does not extend radially beyond the outer diameter ODI of the distal piece 426. In some examples, enclosing the second distal end 310’ of the sheath 308 within the tapered region 434 of the distal piece 426 of the introducer 420 can further include withdrawing the hypotube 470 from the central lumen 476 of the proximal piece 424 such that the distal piece 426 of the introducer abuts the proximal end 440 of the introducer 420.

[0226] In some examples, cutting the sheath 308 includes cutting the sheath 308 at a cut angle relative to the longitudinal axis X of the sheath 308. Specifically, FIG. 30 shows the sheath 308 cut a 90° angle relative to the longitudinal axis X of the sheath 308. However, in further examples, the sheath 308 can be cut at various angles relative to the longitudinal axis X of the sheath so long as the second distal end 310’ of the second section 304 of the sheath 308 can be enclosed within tapered region 434 of introducer 420. For example, the sheath 308 can be cut at an angle of 90° to 135° relative to the longitudinal axis X. In some examples, the sheath 308 can be cut at an angle of 90° to 105° relative to the longitudinal axis X. In some examples, the sheath 308 can be cut at an angle of 90° to 95° relative to the longitudinal axis X. Advantageously, cutting the sheath 308 at an angle at or near 90° facilitates easier coupling with the proximal piece 424 and the distal piece 426 of the introducer 420. For example, cutting the sheath 308 at an angle at or near 90° allows the second distal end 310’ to be evenly received within the tapered region 434 of the distal piece 426 of the introducer 420.

[0227] As provided herein, the sheath 308 is configured to facilitate passage of the delivery apparatus 10 / medical device 12 through an incision site and to a treatment site within a patient’s body. In some examples, it is contemplated that the insertion length Linsertion, and accordingly, the desired second section length L3 (as determined by the cut location 319) is determined before any portion of the sheath 308 is inserted into the incision site. This allows the sheath 308 to be cut away from the patient’s body. Once the sheath 308 is cut and the introducer 420 is coupled with the second section 304 such that the second distal end 310’ is enclosed between the proximal piece 424 and the distal piece 426 of the introducer 420, the coupled introducer 420 and sheath 308 can be inserted at least partially into a blood vessel at the incision site and advanced toward the treatment site. Moving the coupled introducer 420 and sheath 308 into the patient’s blood vessels causes the blood vessels to expand as a result of a radially outwardly directed force provided by the introducer 420.

[0228] In some examples, the introducer 420 can then be uncoupled from the sheath 308 and withdrawn from the patient’s blood vessel. This can include slight advancement of the hypotube 470 axially in a distal direction to cause the distal piece 426 to move from the firstposition to the second position such that the second distal end 310’ can be released from between the proximal piece 424 and the distal piece 426. For example, moving the distal piece 426 to move from the first position to the second position can include advancing the distal piece 426 of the introducer 420 beyond the second distal end 310’ of the sheath 308. In this example, the proximal piece 424 can be retained within the central lumen 312 of the sheath 308 such that the distal piece 426 is axially spaced apart from the proximal piece 424.

[0229] With the sheath 308 uncoupled from the introducer 420, the introducer 420 can then be withdrawn from the sheath 308.

[0230] Once the introducer 420 is removed from the central lumen 312 of the sheath 308, a medical device 12, such as a prosthetic heart valve, can be advanced through the central lumen 312 toward the treatment site, for example, by coupling the medical device 12 to a delivery apparatus 10 and pushing the delivery apparatus through the central lumen 312.

[0231] In some instances, it may be desirable to control the length of the sheath 308 that extends into the patient without modifying the overall length Li of the sheath 308. In other words, a need exists to set an effective length of the sheath 308 that extends into the patient without shortening the sheath 308.

[0232] FIGS. 33-38 refer to an example introducer sheath system 600 including a sheath 308, a sheath hub 340 disposed proximal to the sheath 308, a loader assembly 570 inserted into a proximal end 344 of the sheath hub 340, and a suture hub 550 at least partially surrounding the sheath 308. Advantageously, the suture hub 550 is configured to couple the sheath 308 to the patient and resist axial movement of the sheath 308 relative to the patient, thereby setting the effective sheath length Leff of the sheath 308 that is available to insert into the patient. Furthermore, the loader assembly 570 extends through a central lumen 312 of the sheath 308, thereby providing rigidity and reducing the risk of kinking or poor usability of the sheath 308. These advantages allow for the use of relatively long sheaths in settings where a shorter sheath is desired by limiting the extent to which the sheath 308 can be inserted into the patient.

[0233] It is contemplated that the example sheath 308 illustrated in FIG. 33 can have any of the attributes of the example sheath 308 provided above with respect to FIGS. 25-29B and 30-32. Accordingly, the sheath 308 extends distally from the sheath hub 340 has a sheath length Li, which corresponds to the distance between a distal end 310 and a proximal end 314 of the sheath 308. The sheath 308 defines a central lumen 312 extending longitudinally therethrough. Similarly, it is contemplated that the sheath hub 340 illustrated in FIG. 33 canhave any of the attributes of the sheath hub 340 provided above with respect to FIGS. 25-29B and 30-32.

[0234] As shown in FIG. 33, the introducer sheath system 600 includes a suture hub 550. The suture hub 550 has a suture hub body 552 that includes a proximal surface 554 and a distal surface 556 opposite the proximal surface 554 and defines a central lumen 558 extending longitudinally therethrough. Furthermore, as shown, the suture hub 550 defines one or more openings 560 extending through the suture hub body 552 between the proximal surface 554 and the distal surface 556. As further described herein, the one or more openings 560 facilitate securing the suture hub 550 to the tissue (for example, the skin) of a patient. Specifically, the one or more openings 560 are sized and configured to house a suture thread. In use, a suture thread can be inserted into the one or more openings 560 and also into the skin of the patient, thereby coupling the suture hub 550 to the patient. As further described herein, the distal surface 556 of the suture hub 550 can thus be axially fixed against the skin of a patient. In the illustrated example, the suture hub 550 defines four openings 560 spaced evenly and circumferentially about the central lumen 558. In some examples, the suture hub 550 can define any number of suture openings 560, so long as the openings 560 facilitate coupling the suture hub 550 to the patient’s skin so as to resist axial movement.

[0235] As illustrated in FIG. 33, the suture hub 550 receives the sheath 308 within the central lumen 558. In the illustrated example, the suture hub 550 extends all the way around a circumference of the sheath 308. Advantageously, this configuration ensures that the suture hub 550 cannot inadvertently become decoupled from the sheath 308. However, in some examples, the suture hub 550 may extend around only a portion of the circumference of the sheath 308. For example, the suture hub body 552 of the suture hub 550 may extend between two spaced apart ends so as to define a gap in the suture hub body 552 that is sized and configured to receive the sheath 308. In some examples, the suture hub body 552 may be openable so that the suture hub 550 is movable between an open configuration, in which a gap is defined within the suture hub body 552, and a closed configuration, in which the suture hub body 552 forms a closed loop. Examples of the suture hub 550 that define a gap or are openable enable placement of the 550 around the sheath 308 after the sheath 308 has been inserted into an incision.

[0236] Furthermore, the suture hub 550 is movable between a slidable configuration and a coupled configuration. In the slidable configuration, the sheath 308 is axially slidable within the central lumen 558 of the suture hub 550. Advantageously, this facilitates adjusting the axial position of the suture hub 550 along the length Li of the sheath 308. In the coupledconfiguration, the suture hub 550 prevents the sheath 308 from moving in an axially distal direction relative to the suture hub 550. For example, the suture hub 550 can be sized to form a press-fit with the suture hub 550 such that the sheath 308 resists axial movement relative to the suture hub 550.

[0237] In the example illustrated in FIG. 33, the suture hub 550 includes a locking mechanism 562 that is fixedly coupled with the sheath 308 to resist axial movement of the sheath 308. Specifically, the locking mechanism 562 in the illustrated example includes internal threading extending along the central lumen 558 that engages complimentary threading extending along an external surface of the sheath 308. FIG. 34 shows an enlarged view of the suture hub 550, including circumferentially-spaced openings 560 and a threaded locking mechanism 562. A threaded locking mechanism 562 provides the added advantage of preventing sheath 308 from moving in an axially proximal direction relative to the suture hub 550 without rotation of the sheath 308 relative to the suture hub 550.

[0238] FIG. 35 shows an example suture hub 550 where the central lumen 558 narrows to form a press-fit configuration with the sheath 308 that extends therethrough. In some examples, the central lumen 558 can be tapered to match a corresponding taper of the sheath 308. This configuration facilitates adjustment of the axial position of the sheath 308 relative to the suture hub 550 without rotating the suture hub 550 or sheath 308.

[0239] Returning now to FIG. 33, the position of the suture hub 550 along the length Li of the sheath 308 determines the length of the sheath 308 that is available for insertion into a patient. As shown, the distance between the distal surface 556 of the suture hub 550 and the initial distal end 310 of the sheath 308 defines an effective sheath length Leff. Accordingly, when the suture hub 550 is coupled to both the patient and the sheath 308, the effective sheath length Leff corresponds to the length of the sheath that is received within the patient.

[0240] Furthermore, FIG. 33 shows that the example introducer sheath system 600 includes a loader assembly 570 that is inserted into the sheath hub 340 and sheath 308 to provide rigidity along the length of the sheath 308.

[0241] FIG. 36 illustrates an example loader assembly 570, which includes a base 572, a rigid tube 574 extending distally from the base 572 and defines a loader lumen 576 extending longitudinally through the base 572 and the rigid tube 574. In some examples, including the example illustrated in FIG. 36, the loader assembly 570 includes a loader cap 578 that is positioned at a proximal end of the base 572 and extends the loader lumen 576.

[0242] As shown in FIG. 37, the loader cap 578 includes an opening 580 that is configured to receive a delivery apparatus 10 for implanting a medical device 12. It is contemplated thatthe example delivery apparatus 10 illustrated in FIG. 33 can have any of the attributes of the delivery apparatus 10 provided above with respect to FIGS. 1-3 and can be used for loading a balloon catheter and prosthetic valve into the introducer sheath system 600. As shown in FIG. 38, the delivery apparatus 10 is coupled to the loader assembly 570 by inserting the delivery apparatus 10 into the opening 580 of the loader cap 578 and advancing the delivery apparatus through the loader lumen 576. If the loader assembly 570 is inserted through the sheath hub 340 with delivery device pre-loaded within loader lumen 576, the base 572 and or rigid tube 574 can protect delicate parts of delivery apparatus 10 / medical device 12 from the internal components and seals of the sheath hub 340.

[0243] Returning to FIG. 33, the loader assembly 570 is couplable with the sheath hub 340. Specifically, the loader cap 578 is couplable to the proximal end 344 of the sheath hub 340. When the loader assembly 570 is inserted into the sheath hub 340 and the loader cap 578 is coupled to the sheath hub 340, the rigid tube 574 extends to a location within the sheath 308 that corresponds to the axial location of the suture hub 550 when the sheath 308 is in the coupled configuration. For example, the rigid tube 574 can extend to a location within the sheath 308 that corresponds to the axial location of the distal surface 556 of the suture hub 550 when the sheath 308 is in the coupled configuration. Advantageously, the rigid tube 574 is able to provide rigidity to the introducer sheath system 600 at the incision site and along the length of the sheath 308 that extends outside of the patient’s body. This rigidity reduces the risk of kinking in the sheath 308 and improves stability of the excess length of sheath 308. Accordingly, use of the loader assembly 570 allows for easier handling of a sheath 308 that has a sheath length Li that is longer than the effective sheath length Leff needed to reach a treatment site within a patient.

[0244] As provide herein, the sheath 308 of the introducer sheath system 600 is configured to facilitate passage of the delivery apparatus 10 / medical device 12 through an incision site and toward a treatment site within a patient’s body. In various examples, the incision site corresponds to an access cite to a vascular system of the patient, such as the femoral access site SF, the carotid access site Sc, the axillary access site SA, and / or the subclavian access site Ss shown in FIG. 24. Furthermore, as provided herein, the sheath 308 has an effective sheath length Leff that is defined as the length of the sheath 308 that extends between the distal surface 556 of the suture hub 550 and distal end 310 of the sheath 308. Accordingly, the effective sheath length Leff corresponds to the length of the sheath 308 that is received within the patient.

[0245] In some examples, it is contemplated that the effective sheath length Left is determined before any portion of the sheath 308 is inserted into the incision site. This allows for positioning / coupling of the suture hub 550 to the sheath 308 to be performed away from the patient’s body. The suture hub 550 is axially positioned along the sheath 308 by sliding the suture hub 550 along an outer surface of the 308 so that the sheath 308 extends through a central lumen 558 of the suture hub 550. Once positioned at the desired axial location, the suture hub 550 is fixedly coupled to the sheath 308 to resist axial movement of the sheath 308 relative to the suture hub 550. Once the suture hub 550 is coupled to the sheath 308, the sheath 308 can be inserted at least partially into a blood vessel at the incision site and advanced toward the treatment site until a distal surface 556 of the suture hub 550 abuts the surface of the patient’s skin adjacent to the incision site. The suture hub 550 can then be coupled to the surface of the patient’s skin by fixing the suture hub 550 to the patient’s skin using sutures extending through one or more openings 560 defined by the suture hub 550. With the suture hub 550 coupled to the sheath 308, temporarily suturing the suture hub 550 to the patient’s skin has the effect of setting the effective sheath length Leff that extends into the patient’s vasculature.

[0246] As provided herein, coupling the suture hub 550 to the sheath 308 can comprise engaging an internal threading defined within the central lumen 558 of the suture hub 550 with a threaded external surface of the sheath 308. In some examples, coupling the suture hub 550 to the sheath 308 can comprise engaging a narrowed portion of the central lumen 558 of the suture hub 550 to form a press-fit configuration with the sheath 308.

[0247] However, in some examples, the suture hub 550 can be fixedly coupled to the sheath 308 after the sheath 308 is at least partially inserted into a blood vessel at the incision site. This approach may be useful in instances when determining the effective sheath length Leff is difficult. Under this approach, the suture hub 550 is slid along the outer surface of the sheath 308 until it abuts the surface of the patient’s skin adjacent the incision site. The suture hub 550 can then be fixedly coupled to the surface of the patient’s skin and fixedly coupled to the sheath 308 such that the suture hub 550 resists axial movement of the sheath 308. In some examples, the suture hub 550 is coupled to the surface of the patient’s skin by fixing the suture hub 550 to the patient’s skin using sutures extending through one or more openings 560 defined by the suture hub 550. Once the suture hub 550 and sheath 308 are coupled to the patient, a medical device 12 can be pushed through a central lumen 312 of the sheath 308 toward the treatment site.

[0248] As provided herein, the introducer sheath system 600 can further comprise a loader assembly 570 that is inserted into a central lumen 348 of the sheath hub 340 and into the central lumen 312 of the sheath 308. The loader assembly 570 includes a base 572, a rigid tube 574 extending distally from the base 572 and defines a loader lumen 576 extending longitudinally through the base 572 and the rigid tube 574. Inserting the loader assembly 570 into the sheath hub 340 includes aligning the loader lumen 576 with the central lumen 348 of the sheath hub 340 and the central lumen 312 of the sheath 308.

[0249] In some examples, including the example illustrated in FIG. 36, the loader assembly 570 includes a loader cap 578 that is positioned at a proximal end of the base 572 and extends the loader lumen 576. The loader assembly 570 can be pushed through the central lumen 348 of the sheath hub 340 and the central lumen 312 of the sheath 308 until the rigid tube 574 extends to a location within the sheath 308 that corresponds to the axial location of the suture hub 550 when the suture hub 550 is coupled to the sheath 308.

[0250] With the loader assembly 570 inserted into the sheath hub 340 and sheath 308 and the rigid tube 574 advanced to a desired position therein, the loader assembly 570 can be coupled to the sheath hub 340. For example, the loader cap 578 can be coupled to the proximal end 344 of the sheath hub 340. For example, the loader cap 578 can be threadingly coupled to the proximal end 344 of the sheath hub 340.

[0251] Advantageously, placement of the rigid tube 574 within the sheath 308 provides rigidity to the portion of the sheath 308 that is external to the patient. For example, rigid tube 574 provides rigidity to the portion of the sheath 308 that extends between a proximal end 314 of the sheath 308 and the proximal surface 554 of the suture hub 550, which abuts the surface of the patient’s skin. When a loader assembly 570 is used, the medical device 12 is inserted into the loader lumen 576 through an opening 580 defined in the loader cap 578. Pushing the medical device 12 through the central lumen 312 of the sheath 308 toward the treatment site can thus also include pushing the medical device 12 through the loader lumen 576 of the loader assembly 570.

[0252] Exemplary Aspects

[0253] In view of the described processes and compositions, hereinbelow are described certain more particularly described aspects of the disclosures. These particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein, or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.

[0254] Example 1 : A method of setting a sheath length, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to an initial sheath hub; cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location; wherein cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that extends from the second distal end to the initial proximal end; and coupling the second proximal end of the first section with a second sheath hub.

[0255] Example 2: The method according to any example herein, particularly example 1, further comprising determining an insertion length corresponding to a length of the sheath that is received within the patient's vasculature, wherein the insertion length extends from an incision site to a treatment site.

[0256] Example 3: The method according to any example herein, particularly examples 1-2, further comprising selecting the cut location such that the first section length is equal to or greater than the insertion length.

[0257] Example 4: The method according to any example herein, particularly example 3, wherein the cut location is selected such that the first section length is approximately the insertion length.

[0258] Example 5: The method according to any example herein, particularly examples 1-4, wherein cutting the sheath comprises cutting the sheath at a cut angle relative to a longitudinal axis of the sheath.

[0259] Example 6: The method according to any example herein, particularly example 5, wherein cutting the sheath comprises cutting the sheath at a 90° angle relative to the longitudinal axis of the sheath.

[0260] Example 7 : A method of delivering a medical device through a sheath, the method comprising: handling a radially expandable sheath including a continuous inner layer extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to an initial sheath hub and the inner layer having at least one folded portion extending along a length of the inner layer; cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location, wherein the sheath is divided into a firstsection that extends from the initial distal end to the second proximal end and a second section that extends from the second distal end to the initial proximal end; coupling the second proximal end of the first section with a second sheath hub; inserting the sheath into an incision site of a patient; advancing a medical device through the central lumen of the sheath causing the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to an outwardly directed radial force of the medical device exerted against the inner layer and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen; and advancing the medical device beyond a distal opening of the sheath to the treatment site.

[0261] Example 8: The method according to any example herein, particularly example 7, further comprising: advancing a dilator into the central lumen of the sheath through the second sheath hub; inserting the sheath and coupled dilator at least partially into a blood vessel of a patient at an insertion site; advancing the dilator within the central lumen of the sheath until the dilator is positioned at a treatment site within the patient’s blood vessel, thereby moving the sheath from an unexpanded configuration to an expanded configuration and expanding the patient's blood vessel; and withdrawing the dilator from the central lumen of the sheath.

[0262] Example 9: The method according to any example herein, particularly examples 7-8, wherein the inner layer includes at least one folded portion, wherein locally expanding the central lumen of the sheath causes a length of the folded portion to at least partially unfold.

[0263] Example 10: The method according to any example herein, particularly examples 7- 9, wherein the medical device is a prosthetic device mounted in a radially crimped state on a delivery apparatus.

[0264] Example 11: The method according to any example herein, particularly example 10, wherein the prosthetic device comprises a prosthetic heart valve and the method further comprises implanting the prosthetic heart valve at a treatment site within the patient.

[0265] Example 12: The method according to any example herein, particularly example 11, wherein the prosthetic heart valve is mounted on a balloon catheter of a delivery apparatus as the prosthetic heart valve is advanced through the sheath.

[0266] Example 13: A sheath coupling system comprising: a sheath hub comprising a hub body having a proximal end and a distal end and defining a lumen extending longitudinally therethrough, an initial hub cap coupled to the distal end of the sheath hub, the initial hub cap having an initial hub cap proximal end and an initial hub cap distal end and defining an initialhub cap lumen extending longitudinally therethrough; and a hub coupler coupled to the initial hub cap, the hub coupler comprising a hub coupler body having a hub coupler proximal end and a hub coupler distal end and defining a hub coupler lumen extending longitudinally therethrough, a secondary hub cap disposed distal to the initial hub cap and coupled to the hub coupler, the secondary hub cap having a secondary hub cap proximal end and a secondary hub cap distal end and defining a secondary hub cap lumen extending longitudinally therethrough; a sheath comprising a distal end and a proximal end and defining a central lumen extending longitudinally therethrough, wherein the proximal end of sheath is positioned between the distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub.

[0267] Example 14: The sheath coupling system according to any example herein, particularly example 13, wherein the proximal end of the hub coupler has a radially expanded diameter relative to the distal end of the hub coupler, wherein the proximal end receives the initial hub cap and the distal end is received within the secondary hub cap.

[0268] Example 15: The sheath coupling system according to any example herein, particularly examples 13-14, wherein an inner surface of the hub coupler body has a profile that complements an outer surface of the initial hub cap.

[0269] Example 16: The sheath coupling system according to any example herein, particularly examples 13-15, wherein the proximal end of hub coupler further comprises a tab extending radially inward from the hub coupler body, wherein the tab is configured to couple with a gap formed between the sheath hub and the proximal end of the initial hub cap.

[0270] Example 17: The sheath coupling system according to any example herein, particularly examples 13-16, wherein the hub coupler further comprises a radially outwardly extending threaded region disposed adjacent the distal end, wherein the threaded region is configured to engage a radially inwardly extending threaded region defined at the proximal end of the secondary hub cap.

[0271] Example 18: The sheath coupling system according to any example herein, particularly examples 13-17, wherein the system further comprises an adapter, the adapter comprising an adapter body having a proximal end and a distal end and defining a lumen extending longitudinally therethrough, wherein the adapter tapers from a first adapter diameter at the proximal end to a second adapter diameter at the distal end.

[0272] Example 19: The sheath coupling system according to any example herein, particularly example 18, wherein the first adapter diameter is sized and configured to receivethe distal end of the hub coupler, and the second adapter diameter is sized and configured to be received within a proximal end of the sheath.

[0273] Example 20: The sheath coupling system according to any example herein, particularly examples 13-19, wherein the system further comprises a coupler seal disposed between the distal end of the hub coupler and the threaded region of the secondary hub cap.

[0274] Example 21: A method of setting a sheath length, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to an initial sheath hub cap, and the initial sheath hub cap coupled to a sheath hub; cutting the sheath at a first cut location between the initial distal end and the initial proximal end so as to form a second distal end and a second proximal end on either side of the cut location; cutting the sheath at a second cut location between the first cut location and the initial distal end so as to form a third distal end and a third proximal end on either side of the second cut location, wherein cutting the sheath at the first cut location and second cut location divides the sheath into a first section that has a first section length extending from the initial distal end to the third proximal end, a second section that has a second section length extending from the third distal end to the second proximal end, and a third section that has a third section length extending from the second distal end to the initial proximal end; coupling a proximal end of a hub coupler to a distal end of the sheath hub; and coupling a proximal end of a secondary hub cap to a distal end of the hub coupler, wherein the sheath is positioned between a distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary sheath hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub.

[0275] Example 22: The method according to any example herein, particularly example 21, wherein the first cut location is adjacent the distal end of the initial sheath hub cap.

[0276] Example 23: The method according to any example herein, particularly examples 21-22, further comprising determining an insertion length corresponding to a length of the sheath that is received within the patient's vasculature, wherein the insertion length extends from an incision site to a treatment site.

[0277] Example 24: The method according to any example herein, particularly examples 21-23, further comprising selecting the first cut location and second cut location such that a combined length of the first section length and third section length is equal to or greater than the insertion length.

[0278] Example 25: The method according to any example herein, particularly example 24, wherein the first cut location and second cut location are selected such that combined length of the first section length and third section length is approximately the insertion length.

[0279] Example 26: The method according to any example herein, particularly examples 21-25, wherein cutting the sheath at a first cut location comprises cutting the sheath at a first cut angle relative to a longitudinal axis of the sheath.

[0280] Example 27 : The method according to any example herein, particularly example 26, wherein cutting the sheath at a first cut location comprises cutting the sheath at a 90° angle relative to the longitudinal axis of the sheath.

[0281] Example 28: The method according to any example herein, particularly examples 21-27, wherein cutting the sheath at a second cut location comprises cutting the sheath at a second cut angle relative to a longitudinal axis of the sheath.

[0282] Example 29: The method according to any example herein, particularly example 28, wherein cutting the sheath at a second cut location comprises cutting the sheath at a 90° angle relative to the longitudinal axis of the sheath.

[0283] Example 30: The method according to any example herein, particularly examples 21-29, wherein coupling the proximal end of a hub coupler to the distal end of the sheath hub further comprises coupling a tab extending radially inward from the hub coupler body with a gap formed between the sheath hub and the proximal end of the initial hub cap.

[0284] Example 31 : The method according to any example herein, particularly examples 21-30, wherein coupling the proximal end of the secondary hub cap to the distal end of the hub coupler further comprises providing and / or positioning a coupler seal between the distal end of the hub coupler and the threaded region of the secondary hub cap.

[0285] Example 32: The method according to any example herein, particularly examples 21-31, further comprising inserting the distal end of the hub coupler into the third proximal end of the first section of the sheath.

[0286] Example 33: The method according to any example herein, particularly examples 21-32, further comprising coupling the proximal end of an adapter to the distal end of hub coupler, wherein the adapter tapers from a first adapter diameter at the proximal end to a second adapter diameter at a distal end.

[0287] Example 34: The method according to any example herein, particularly example 33, further comprising inserting distal end of the adapter into the third proximal end" of the sheath.

[0288] Example 35: A method of delivering a medical device, the method comprising handling a radially expandable sheath including a continuous inner layer extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to an initial sheath hub cap, the initial sheath hub cap coupled to a sheath hub, and the inner layer having at least one folded portion extending along a length of the inner layer; cutting the sheath at a first cut location between the initial distal end and the initial proximal end so as to form a second distal end and a second proximal end on either side of the cut location; cutting the sheath at a second cut location between the first cut location and the initial distal end so as to form a third distal end and a third proximal end on either side of the second cut location, wherein cutting the sheath at the first cut location and second cut location divides the sheath into a first section that has a first section length extending from the initial distal end to the third proximal end, a second section that has a second section length extending from the third distal end to the second proximal end, and a third section that has a third section length extending from the second distal end to the initial proximal end; coupling a proximal end of a hub coupler to a distal end of the hub; coupling a proximal end of a secondary hub cap to a distal end of the hub coupler, wherein the sheath is positioned between a distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary sheath hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub; inserting the sheath into an incision site of a patient; advancing a medical device through the central lumen of the sheath causing the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to an outwardly directed radial force of the medical device exerted against the inner layer and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen; and advancing the medical device beyond a distal opening of the sheath to the treatment site.

[0289] Example 36: The method according to any example herein, particularly example 35, further comprising: advancing a dilator into the central lumen of the sheath through the sheath hub; inserting the sheath and coupled dilator at least partially into a blood vessel of a patient at an insertion site; advancing the dilator within the central lumen of the sheath until the dilator is positioned at a treatment site within the patient's blood vessel, thereby moving the sheath from an unexpanded configuration to an expanded configuration and expanding the patient’s blood vessel; and withdrawing the dilator from the central lumen of the sheath.

[0290] Example 37 : The method according to any example herein, particularly examples 35-36, wherein the inner layer includes at least one folded portion, wherein locally expanding the central lumen of the sheath causes a length of the folded portion to at least partially unfold.

[0291] Example 38: The method according to any example herein, particularly examples 35-37, wherein the medical device is a prosthetic device mounted in a radially crimped state on a delivery apparatus.

[0292] Example 39: The method according to any example herein, particularly example 38, wherein the prosthetic device comprises a prosthetic heart valve and the method further comprises implanting the prosthetic heart valve at a treatment site within the patient.

[0293] Example 40: The method according to any example herein, particularly example 39, wherein the prosthetic heart valve is mounted on a balloon catheter of a delivery apparatus as the prosthetic heart valve is advanced through the sheath.

[0294] Example 41: An introducer sheath system comprising: a sheath extending a length between a distal end and a proximal end and defining a central lumen extending longitudinally therethrough; an introducer locking hub comprising a hub body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end; and an introducer coupled to the introducer locking hub and received within the sheath, the introducer extending beyond the distal end of the hub body, the introducer comprising a proximal piece and a separate distal piece, the proximal piece coupled to the introducer locking hub and defining a central lumen extending therethrough, wherein the distal end of the sheath is provided between the proximal piece and the distal piece of the introducer such that the distal end of the sheath does not extend radially beyond an outer diameter of the distal piece of the introducer.

[0295] Example 42: The introducer system according to any example herein, particularly example 41, wherein the distal piece of the introducer is movable from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece.

[0296] Example 43: The introducer system according to any example herein, particularly examples 41-42, wherein the distal piece comprises a tapered inner surface that widens toward a proximal end of the distal piece, wherein the distal end of the sheath is provided within the tapered inner surface.

[0297] Example 44: The introducer system according to any example herein, particularly example 43, wherein the proximal piece comprises a tapered outer surface that is complementary to the tapered inner surface of the distal piece.

[0298] Example 45: The introducer system according to any example herein, particularly example 44, wherein the distal end of the sheath is provided longitudinally between the tapered inner surface of the distal piece and the tapered outer surface of the proximal piece.

[0299] Example 46: The introducer system according to any example herein, particularly examples 41-45, further comprising a sheath hub with a central lumen extending therethrough, the sheath hub coupled to the proximal end of the sheath, the central lumen of the sheath hub aligned with the central lumens ,458 of the sheath and the introducer locking hub.

[0300] Example 47 : The introducer system according to any example herein, particularly examples 41-46, further comprising a hypotube disposed within the central lumen of the introducer, the hypotube having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end.

[0301] Example 48: The introducer system according to any example herein, particularly example 47, wherein the distal end of the hypotube is coupled to the distal piece of the introducer and at least a portion of the hypotube is slidably disposed in the central lumen of the proximal piece of the introducer such that movement of the hypotube within the central lumen of the proximal piece causes the distal piece of the introducer to move with respect to the proximal piece of the introducer.

[0302] Example 49: The introducer system according to any example herein, particularly example 48, wherein axial movement of the hypotube within the central lumen of the proximal piece of the introducer causes a corresponding axial movement of the distal piece of the introducer, wherein, when the introducer is in the first position, axial movement of the hypotube in a distal direction causes the distal piece to move from the first position to the second position, wherein, when the introducer is in the second position, axial movement of the hypotube in a proximal direction causes the distal piece to move from the second position to the first position.

[0303] Example 50: A method of setting a sheath length, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to a sheath hub; cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location, wherein cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that has a second section lengthextending from the second distal end to the initial proximal end; inserting an introducer into the sheath hub and advancing the introducer through the central lumen of the sheath; moving a distal piece of the introducer from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece, wherein the distal piece comprises a proximal end and a distal end, wherein the proximal end of the distal piece comprises a tapered region that tapers radially inward toward the distal end; and enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer.

[0304] Example 51 : The method according to any example herein, particularly example 50, further comprising enclosing the initial distal end of the sheath between the tapered region of the distal piece and a complementary tapered region of the proximal piece.

[0305] Example 52: The method according to any example herein, particularly examples 50-51, wherein moving the distal piece of the introducer from the first position to the second position further comprises advancing a hypotube slidably disposed within a central lumen of the proximal piece and coupled to the distal piece axially in a distal direction.

[0306] Example 53: A method of delivering a medical device, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to a sheath hub; cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location, wherein cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that has a second section length extending from the second distal end to the initial proximal end; inserting an introducer into the sheath hub and advancing the introducer through the central lumen of the sheath; moving a distal piece of the introducer from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece, wherein the distal piece comprises a proximal end and a distal end, wherein the proximal end of the distal piece comprises a tapered region that tapers radially inward toward the distal end; and enclosing the second distal end of the sheath within the tapered region of the distal piece of the introducer; pushing the coupled sheath and introducer at least partially into the vasculature of a patient; withdrawing the introducer from the central lumen of the sheath; pushing a medical device through the central lumen of the sheath toward a treatment site; and delivering the medical device to the treatment site via the central lumen of the sheath.

[0307] Example 54: The method according to any example herein, particularly example 53, further comprising coupling the introducer to an introducer locking hub, the introducer locking hub comprising a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end, wherein the introducer extends distally from the introducer locking hub.

[0308] Example 55: The method according to any example herein, particularly example 54, further comprising coupling the distal end of the introducer locking hub to the proximal end sheath hub such that an axial position of the introducer locking hub relative to the sheath hub is fixed.

[0309] Example 56: The method according to any example herein, particularly examples 53-55, wherein moving the distal piece of the introducer from the first position to the second position further comprises advancing the distal piece of the introducer beyond the second distal end of the sheath.

[0310] Example 57: The method according to any example herein, particularly example 56, wherein advancing the distal piece of the introducer beyond the second distal end of the sheath further comprises retaining the proximal piece within the central lumen of the sheath such that the distal piece is axially spaced apart from the proximal piece.

[0311] Example 58: The method according to any example herein, particularly examples 53-57, wherein enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer further comprises withdrawing the distal piece in a proximal direction toward the proximal piece, thereby holding the second distal end of the sheath longitudinally between the distal piece and the proximal piece.

[0312] Example 59: The method according to any example herein, particularly example 58, further comprising coupling a hypotube to the distal piece, the hypotube slidably disposed within the central lumen of the proximal piece.

[0313] Example 60: The method according to any example herein, particularly example 59, wherein moving the distal piece of the introducer from the first position to the second position further comprises pushing the hypotube distally within the central lumen of the proximal piece.

[0314] Example 61: The method according to any example herein, particularly examples 59-60, wherein enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer further comprises withdrawing the hypotube from the central lumen of the proximal piece such that the distal piece of the introducer abuts the proximal piece of the introducer.

[0315] Example 62: An introducer sheath system comprising: a sheath hub comprising a proximal end and distal end and defining a lumen extending longitudinally therethrough; a sheath coupled to and extending distally from the sheath hub, the sheath extending a sheath length between a distal end and a proximal end and defining a central lumen extending longitudinally therethrough; and a suture hub at least partially surrounding the sheath, the suture hub having a suture hub body with a proximal surface and a distal surface and defining a central lumen extending longitudinally therethrough, the suture hub further comprising one or more openings sized to house a suture for securing the suture hub to a patient; wherein the sheath is movable between a slidable configuration, in which the sheath is axially slidable within the central lumen of the suture hub, and a coupled configuration, in which the sheath is fixedly coupled to a locking mechanism on the suture hub to resist axial movement of the sheath; and wherein an effective sheath length corresponding to a length of the sheath that is received within the patient is defined as the length of the sheath between distal surface of the suture hub and the distal end of the sheath.

[0316] Example 63: The introduce sheath system according to any example herein, particularly example 62, further comprising a loader assembly insertable within the sheath hub, the loader assembly comprising a base, a rigid tube extending distally from the base, and defining a loader lumen extending longitudinally through the base and the rigid tube, wherein when inserted into the sheath hub, the rigid tube extends to a location within the sheath corresponding to the axial location of the suture hub when the sheath is in the coupled configuration.

[0317] Example 64: The introduce sheath system according to any example herein, particularly examples 62-63, wherein the locking mechanism comprises internal threading that engages a threaded external surface of the sheath.

[0318] Example 65: The introduce sheath system according to any example herein, particularly examples 62-63, wherein the locking mechanism comprises a narrowing of central lumen to form a press-fit configuration with the sheath.

[0319] Example 66: The introduce sheath system according to any example herein, particularly examples 63-65, wherein the rigid tube extends to a location within the sheath corresponding to the axial location of the distal surface of the suture hub when the sheath is in the coupled configuration.

[0320] Example 67 : The introduce sheath system according to any example herein, particularly example 66, wherein the loader assembly further comprises a loader cap that defines a lumen therethrough, the loader cap couplable to the proximal end of the sheath hub.

[0321] Example 68: A method of delivering a medical device through a sheath, the method comprising: inserting a sheath into a patient at an incision site; pushing a distal end of the sheath to a location within the patient's vasculature adjacent a treatment site; sliding a suture hub along an outer surface of the sheath; coupling the suture hub to a surface of the patient's skin adjacent to the incision site; fixedly coupling the suture hub and the sheath so as to resist axial movement of the sheath, wherein an effective sheath length is defined as the length of the sheath that extends between a distal surface of the suture hub and the distal end of the sheath and corresponds to a length of the sheath that is received within a patient; and pushing a medical device through the sheath toward the treatment site.

[0322] Example 69: The method according to any example herein, particularly example 68, further comprising inserting a loader assembly into a lumen of a sheath hub and into a central lumen of the sheath, the loader assembly comprising a base, a rigid tube extending distally from the base, and defining a loader lumen extending longitudinally through the base and the rigid tube, wherein the loader lumen is aligned with the lumen of the sheath hub and the central lumen of the sheath; and pushing the loader assembly into the lumen until the rigid tube extends to a location within the sheath corresponding to the axial location of the suture hub when the suture hub is coupled to the sheath, thereby providing rigidity to a portion of the sheath extending between the proximal end of the sheath and the proximal surface of the suture hub, which corresponds to a portion of the sheath that is external to the patient, wherein pushing the medical device through the sheath toward the treatment site further comprises pushing the medical device through the loader assembly.

[0323] Example 70: The method according to any example herein, particularly examples 68-69, wherein coupling the distal surface of the suture hub to a surface of a patient's skin at an incision site further comprises fixing the suture hub to the patient's skin using sutures extending through an opening defined by the suture hub.

[0324] Example 71: The method according to any example herein, particularly examples68-70, wherein the incision site corresponds to an access site to a vascular system of the patient.

[0325] Example 72: The method according to any example herein, particularly examples69-71, further comprising coupling the loader assembly to the proximal end of the sheath hub.

[0326] Example 73: The method according to any example herein, particularly example 72, wherein coupling the loader assembly to the sheath hub further comprises coupling a loading cap to the proximal end of the sheath hub, the loading cap defining an opening therein.

[0327] Example 74: The method according to any example herein, particularly examples 72-73, further comprising inserting the medical device into the loader lumen through the opening.

[0328] Example 75: The method according to any example herein, particularly examples 68-74, wherein coupling the suture hub and the sheath further comprises engaging an internal threading defined within the central lumen of the suture hub with a threaded external surface of the sheath.

[0329] Example 76: The method according to any example herein, particularly examples 68-74, wherein coupling the suture hub and the sheath further comprises engaging a narrowed portion of the central lumen of the suture hub to form a press-fit configuration with the sheath.

[0330] In view of the many possible aspects to which the principles of the disclosed disclosure can be applied, it should be recognized that the illustrated aspects are only preferred examples of the disclosure and should not be taken as limiting the scope of the disclosure. Rather, the scope of the disclosure is defined by the following claims. We, therefore, claim as our disclosure all that comes within the scope and spirit of these claims.

Claims

CLAIMSWhat is claimed is:

1. A sheath coupling system comprising: a sheath hub comprising a hub body having a proximal end and a distal end and defining a lumen extending longitudinally therethrough; an initial hub cap coupled to the distal end of the sheath hub, the initial hub cap having an initial hub cap proximal end and an initial hub cap distal end and defining an initial hub cap lumen extending longitudinally therethrough; and a hub coupler coupled to the initial hub cap, the hub coupler comprising a hub coupler body having a hub coupler proximal end and a hub coupler distal end and defining a hub coupler lumen extending longitudinally therethrough; a secondary hub cap disposed distal to the initial hub cap and coupled to the hub coupler, the secondary hub cap having a secondary hub cap proximal end and a secondary hub cap distal end and defining a secondary hub cap lumen extending longitudinally therethrough; and a sheath comprising a distal end and a proximal end and defining a central lumen extending longitudinally therethrough, wherein the proximal end of the sheath is positioned between the distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub.

2. The sheath coupling system according to claim 1 , wherein the proximal end of the hub coupler has a radially expanded diameter relative to the distal end of the hub coupler, wherein the proximal end receives the initial hub cap and the distal end is received within the secondary hub cap.

3. The sheath coupling system according to any one of claims 1-2, wherein the proximal end of hub coupler further comprises a tab extending radially inward from the hub coupler body, wherein the tab is configured to couple with a gap formed between the sheath hub and the proximal end of the initial hub cap.

4. The sheath coupling system according to any one of claims 1-3, wherein the system further comprises an adapter, the adapter comprising an adapter body having a proximal end and a distal end and defining a lumen extending longitudinally therethrough, wherein the adapter tapers from a first adapter diameter at the proximal end to a second adapter diameter at the distal end, wherein the first adapter diameter is sized and configured to receive the distal end of the hub coupler, and the second adapter diameter is sized and configured to be received within a proximal end of the sheath.

5. The sheath coupling system according to any one of claims 1-4, wherein the hub coupler further comprises a radially outwardly extending threaded region disposed adjacent the distal end, wherein the threaded region is configured to engage a radially inwardly extending threaded region defined at the proximal end of the secondary hub cap, wherein the system further comprises a coupler seal disposed between the distal end of the hub coupler and the threaded region of the secondary hub cap.

6. A method of setting a sheath length, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to an initial sheath hub cap, and the initial sheath hub cap coupled to a sheath hub; cutting the sheath at a first cut location between the initial distal end and the initial proximal end so as to form a second distal end and a second proximal end on either side of the cut location; cutting the sheath at a second cut location between the first cut location and the initial distal end so as to form a third distal end and a third proximal end on either side of the second cut location, wherein cutting the sheath at the first cut location and second cut location divides the sheath into a first section that has a first section length extending from the initial distal end to the third proximal end, a second section that has a second section length extending from the third distal end to the second proximal end, and a third section that has a third section length extending from the second distal end to the initial proximal end; coupling a proximal end of a hub coupler to a distal end of the sheath hub; and coupling a proximal end of a secondary hub cap to a distal end of the hub coupler,wherein the sheath is positioned between a distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary sheath hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub.

7. The method according to claim 6, further comprising selecting the first cut location and second cut location such that a combined length of the first section length and third section length is equal to or greater than an insertion length, wherein the first cut location and second cut location are selected such that combined length of the first section length and third section length is approximately the insertion length.

8. The method according to any one of claims 6-7, wherein coupling the proximal end of a hub coupler to the distal end of the sheath hub further comprises coupling a tab extending radially inward from a hub coupler body with a gap formed between the sheath hub and the proximal end of the initial hub cap.

9. The method according to any one of claims 6-8, wherein coupling the proximal end of the secondary hub cap to the distal end of the hub coupler further comprises positioning a coupler seal between the distal end of the hub coupler and the threaded region of the secondary hub cap.

10. The method according to any one of claims 6-9, further comprising coupling the proximal end of an adapter to the distal end of hub coupler, wherein the adapter tapers from a first adapter diameter at the proximal end to a second adapter diameter at a distal end.

11. A method of delivering a medical device, the method comprising: handling a radially expandable sheath including a continuous inner layer extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to an initial sheath hub cap, the initial sheath hub cap coupled to a sheath hub, and the inner layer having at least one folded portion extending along a length of the inner layer; cutting the sheath at a first cut location between the initial distal end and the initial proximal end so as to form a second distal end and a second proximal end on either side of the cut location;cutting the sheath at a second cut location between the first cut location and the initial distal end so as to form a third distal end and a third proximal end on either side of the second cut location, wherein cutting the sheath at the first cut location and second cut location divides the sheath into a first section that has a first section length extending from the initial distal end to the third proximal end, a second section that has a second section length extending from the third distal end to the second proximal end, and a third section that has a third section length extending from the second distal end to the initial proximal end; coupling a proximal end of a hub coupler to a distal end of the hub; coupling a proximal end of a secondary hub cap to a distal end of the hub coupler, wherein the sheath is positioned between a distal end of the secondary hub cap and the distal end of the hub coupler such that coupling the secondary sheath hub cap to the hub coupler fixes the sheath to the hub coupler and to the sheath hub; inserting the sheath into an incision site of a patient; advancing a medical device through the central lumen of the sheath causing the sheath to locally expand from an unexpanded configuration to the expanded configuration at a location proximate the medical device in response to an outwardly directed radial force of the medical device exerted against the inner layer and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen; and advancing the medical device beyond a distal opening of the sheath to a treatment site.

12. The method according to claim 11, further comprising: advancing a dilator into the central lumen of the sheath through the sheath hub; inserting the sheath and coupled dilator at least partially into a blood vessel of a patient at an insertion site; advancing the dilator within the central lumen of the sheath until the dilator is positioned at a treatment site within the patient’s blood vessel, thereby moving the sheath from an unexpanded configuration to an expanded configuration and expanding the patient’s blood vessel; and withdrawing the dilator from the central lumen of the sheath.

13. An introducer sheath system comprising:a sheath extending a length between a distal end and a proximal end and defining a central lumen extending longitudinally therethrough; an introducer locking hub comprising a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end; and an introducer coupled to the introducer locking hub and received within the sheath, the introducer extending beyond the distal end of the introducer locking hub, the introducer comprising a proximal piece and a separate distal piece, the proximal piece coupled to the introducer locking hub and defining a central lumen extending therethrough, wherein the distal end of the sheath is provided between the proximal piece and the distal piece of the introducer such that the distal end of the sheath does not extend radially beyond an outer diameter of the distal piece of the introducer, wherein the distal piece of the introducer is movable from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece.

14. The introducer sheath system according to claim 13, wherein the distal piece comprises a tapered inner surface that widens toward a proximal end of the distal piece, wherein the distal end of the sheath is provided within the tapered inner surface, wherein the proximal piece comprises a tapered outer surface that is complementary to the tapered inner surface of the distal piece.

15. The introducer sheath system according to any one of claims 13-14, further comprising a hypotube disposed within the central lumen of the introducer, the hypotube having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end, wherein the distal end of the hypotube is coupled to the distal piece of the introducer and at least a portion of the hypotube is slidably disposed in the central lumen of the proximal piece of the introducer such that movement of the hypotube within the central lumen of the proximal piece causes the distal piece of the introducer to move with respect to the proximal piece of the introducer.

16. A method of setting a sheath length, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to a sheath hub;cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location, wherein cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that has a second section length extending from the second distal end to the initial proximal end; inserting an introducer into the sheath hub and advancing the introducer through the central lumen of the sheath; moving a distal piece of the introducer from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece, wherein the distal piece comprises a proximal end and a distal end, wherein the proximal end of the distal piece comprises a tapered region that tapers radially inward toward the distal end; and enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer.

17. The method according to claim 16, further comprising enclosing the initial distal end of the sheath between the tapered region of the distal piece and a complementary tapered region of the proximal piece.

18. The method according to any one of claims 16-17, wherein moving the distal piece of the introducer from the first position to the second position further comprises advancing a hypotube slidably disposed within a central lumen of the proximal piece and coupled to the distal piece axially in a distal direction.

19. A method of delivering a medical device, the method comprising: handling a sheath, the sheath extending an initial sheath length between an initial distal end and an initial proximal end and defining a central lumen extending longitudinally therethrough, the initial proximal end of the sheath coupled to a sheath hub; cutting the sheath at a cut location between the initial distal end and the initial proximal end so as to form a second proximal end and a second distal end on either side of the cut location, wherein cutting the sheath divides the sheath into a first section that has a first section length extending from the initial distal end to the second proximal end and a second section that has a second section length extending from the second distal end to the initial proximal end;inserting an introducer into the sheath hub and advancing the introducer through the central lumen of the sheath; moving a distal piece of the introducer from a first position adjacent the proximal piece to a second position axially spaced from the proximal piece, wherein the distal piece comprises a proximal end and a distal end, wherein the proximal end of the distal piece comprises a tapered region that tapers radially inward toward the distal end; and enclosing the second distal end of the sheath within the tapered region of the distal piece of the introducer; pushing the coupled sheath and introducer at least partially into the vasculature of a patient; withdrawing the introducer from the central lumen of the sheath; pushing a medical device through the central lumen of the sheath toward a treatment site; and delivering the medical device to the treatment site via the central lumen of the sheath.

20. The method according to claim 19, further comprising: coupling the introducer to an introducer locking hub, the introducer locking hub comprising a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end, wherein the introducer extends distally from the introducer locking hub, and coupling the distal end of the introducer locking hub to the proximal end sheath hub such that an axial position of the introducer locking hub relative to the sheath hub is fixed.

21. The method according to any one of claims 19-20, wherein moving the distal piece of the introducer from the first position to the second position further comprises advancing the distal piece of the introducer beyond the second distal end of the sheath while retaining the proximal piece within the central lumen of the sheath such that the distal piece is axially spaced apart from the proximal piece.

22. The method according to any one of claims 19-21, wherein enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer further comprises withdrawing the distal piece in a proximal direction toward the proximal piece, thereby holding the second distal end of the sheath longitudinally between the distal piece and the proximal piece.

23. The method according to claim 22, further comprising coupling a hypotube to the distal piece, the hypotube slidably disposed within the central lumen of the proximal piece, wherein enclosing the initial distal end of the sheath within the tapered region of the distal piece of the introducer further comprises withdrawing the hypotube from the central lumen of the proximal piece such that the distal piece of the introducer abuts the proximal piece of the introducer.

24. An introducer sheath system comprising: a sheath hub comprising a proximal end and distal end and defining a lumen extending longitudinally therethrough; a sheath coupled to and extending distally from the sheath hub, the sheath extending a sheath length between a distal end and a proximal end and defining a central lumen extending longitudinally therethrough; and a suture hub at least partially surrounding the sheath, the suture hub having a suture hub body with a proximal surface and a distal surface and defining a central lumen extending longitudinally therethrough, the suture hub further comprising one or more openings sized to house a suture for securing the suture hub to a patient; wherein the sheath is movable between a slidable configuration, in which the sheath is axially slidable within the central lumen of the suture hub, and a coupled configuration, in which the sheath is fixedly coupled to a locking mechanism on the suture hub to resist axial movement of the sheath; and wherein an effective sheath length corresponding to a length of the sheath that is received within the patient is defined as the length of the sheath between distal surface of the suture hub and the distal end of the sheath.

25. The introducer sheath system of claim 24, further comprising a loader assembly insertable within the sheath hub, the loader assembly comprising a base, a rigid tube extending distally from the base, and defining a loader lumen extending longitudinally through the base and the rigid tube, wherein when inserted into the sheath hub, the rigid tube extends to a location within the sheath corresponding to an axial location of the suture hub when the sheath is in the coupled configuration.

26. A method of delivering a medical device through a sheath, the method comprising: inserting a sheath into a patient at an incision site; pushing a distal end of the sheath to a location within the patient’s vasculature adjacent a treatment site; sliding a suture hub along an outer surface of the sheath; coupling the suture hub to a surface of the patient’s skin adjacent to the incision site, wherein coupling the distal surface of the suture hub to a surface of a patient’s skin at an incision site further comprises fixing the suture hub to the patient’s skin using sutures extending through an opening defined by the suture hub; fixedly coupling the suture hub and the sheath so as to resist axial movement of the sheath, wherein an effective sheath length is defined as the length of the sheath that extends between a distal surface of the suture hub and the distal end of the sheath and corresponds to a length of the sheath that is received within a patient; and pushing a medical device through the sheath toward the treatment site.

27. The method of claim 26, further comprising inserting a loader assembly into a lumen of a sheath hub and into a central lumen of the sheath, the loader assembly comprising a base, a rigid tube extending distally from the base, and defining a loader lumen extending longitudinally through the base and the rigid tube, wherein the loader lumen is aligned with the lumen of the sheath hub and the central lumen of the sheath; and pushing the loader assembly into the lumen until the rigid tube extends to a location within the sheath corresponding to the axial location of the suture hub when the suture hub is coupled to the sheath, thereby providing rigidity to a portion of the sheath extending between a proximal end of the sheath and a proximal surface of the suture hub, which corresponds to a portion of the sheath that is external to the patient, wherein pushing the medical device through the sheath toward the treatment site further comprises pushing the medical device through the loader assembly.

28. The method claim 27, further comprising coupling the loader assembly to a proximal end of the sheath hub,wherein coupling the loader assembly to the sheath hub further comprises coupling a loading cap to the proximal end of the sheath hub, the loading cap defining an opening therein.

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