Sheath system stabilizer for controlling expansion

Abstract

Disclosed herein is an introducer sheath assembly (300). The introducer sheath assembly includes a sheath (308) for deploying a medical device and a radial stabilizer (360) extending at least partially around the sheath for controlling radial expansion of a portion of the sheath extending outside of a patient.

Description

Attorney Docket No.: THVDL-23911WO01SHEATH SYSTEM STABILIZER FOR CONTROLLING EXPANSIONCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 699,621, filed September 26, 2024, which is incorporated by reference in its entirety for all purposes.FIELD

[0002] The present application is directed to a sheath and introducer / dilator for use with catheter-based 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 a prosthetic valve, 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 reach target destinations rather than surgically opening target site. There are many types of diseases states that can be treated via interventional methods including coronary blockages, valve replacements (TAVR) and brain aneurysms. These techniques involve using 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 which is responsible for treating the disease state. 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 techniques can usually be performed much faster, and with fewer clinicians participating in the procedure, so overall costs are lowered. In some cases, the need for anesthesia is also eliminated, further speeding up the recovery process and reducing risk.

[0005] 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 removed from the access site sequentially. For example, a guide wire is used to track the correctAttorney Docket No.: THVDL-23911WO01 location within the body. Next a balloon may be used to dilate a section of narrowed blood vessel. Last, an implant may be delivered to the target site. Because catheters are frequently inserted and removed, introducer sheaths are used to protect the local anatomy and simplify the procedure.

[0006] An introducer sheath can be used to safely introduce a delivery apparatus into a patient’s vasculature via a vascular incision site. Introducer sheaths are conduits that seal onto the access site blood vessel to reduce bleeding and trauma to the vessel caused by catheters with rough edges. An introducer sheath generally has an elongated sleeve that is inserted into the vasculature and a housing that 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 shaft of the delivery apparatus is advanced through the sheath and into the vasculature, carrying the prosthetic device. Expandable introducer sheaths, formed of highly elastomeric materials, allow for the dilating of the vessel to be performed by the passing prosthetic device.

[0007] 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, then 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. 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. Unfortunately, conventional introducer sheaths that are designed for the femoral approach are not well suited for use in these alternative vascular incision site.

[0008] Accordingly, there remains a need for systems and methods that reduce the push force needed to introduce the delivery device and medical device to the treatment location within a patient’s blood vessel. Additionally, there remains a need for systems and methods that facilitate use of introducer sheath systems at alternative vascular incision sites.SUMMARY OF THE INVENTIONAttorney Docket No.: THVDL-23911WO01

[0009] Implementations of the present expandable sheath system can minimize trauma to the vessel and damage to the sheath and prosthetic device by reducing push forces through the blood vessel and / or sheath by providing a combined introducer-dilator that can be used to dilate the blood vessel and or sheath before the delivery device / medical device is introduced. Some examples can comprise a sheath with a smaller profile than that of prior art introducer sheaths. Furthermore, certain 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 lower push force is required and only one sheath is used, rather than several different sizes of sheaths and / or dilators.

[0010] In one of its basic configurations, the present disclosure provides devices, systems, and methods including a radial stabilizer that resists radial expansion of the sheath and particularly prevents excessive radial expansion of a portion of the sheath that is left outside the patient’s body during the procedure. 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 features of the examples described hereafter.

[0011] An example sheath assembly according to the present disclosure includes: a sheath for deploying a medical device; and a radial stabilizer extending around at least a portion of the sheath, wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond an inner diameter of the radial stabilizer.

[0012] An example sheath assembly according to the present disclosure includes: a sheath for deploying a medical device, the sheath having a distal end and a proximal end with a central lumen extending therebetween; and a radial stabilizer having a distal end and a proximal end and a body extending therebetween, wherein the proximal end of the radial stabilizer is disposed adjacent the proximal end of the sheath, wherein the body defines a longitudinal cavity having an inner diameter, wherein the radial stabilizer extends around at least a portion of a circumference of the sheath such that the sheath extends through the longitudinal cavity, wherein a distance between the proximal end and the distal end of the radial stabilizer is less than a distance between the proximal end and distal end of the sheath, , and wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond the inner diameter of the radial stabilizer.Attorney Docket No.: THVDL-23911WO01

[0013] In some examples, the proximal end of the radial stabilizer is coupled to the proximal end of the sheath and / or a sheath hub cap and / or a sheath hub, wherein the sheath hub cap and the sheath hub are coupled to the proximal end of the sheath.

[0014] In some examples, the distal end of the radial stabilizer includes a distally-facing contact surface. In some examples, the contact surface includes an annular ring.

[0015] In some examples, the distance between the proximal end and the distal end of the radial stabilizer is axially adjustable along the longitudinal axis of the sheath between an extended configuration and a contracted configuration.

[0016] In some examples, the extended configuration, the distance between the proximal end and the distal end of the radial stabilizer defines a first length, and in the contracted configuration, the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length. In some examples, the second length of the radial stabilizer is less than or equal to 50% the length of the sheath.

[0017] In some examples, the proximal end of the radial stabilizer is substantially stationary.

[0018] In some examples, the body of the radial stabilizer is a spring including a plurality of coils.

[0019] In some examples, the radial stabilizer includes a plurality of tubular bodies extending along the longitudinal axis of the radial stabilizer, the plurality of tubular bodies including a first tubular body and one or more additional tubular bodies, wherein each tubular body includes a distal end and a proximal end and defines a longitudinal cavity, wherein the combination of the longitudinal cavities of each of the tubular bodies form the longitudinal cavity of the radial stabilizer.

[0020] In some examples, each of the one or more additional tubular bodies is displaceable relative to the first tubular body along the longitudinal axis.

[0021] In some examples, the proximal end of the first tubular body defines the proximal end of the radial stabilizer.

[0022] In some examples, when the radial stabilizer is in the extended configuration, the one or more additional tubular bodies are axially displaced relative to the first tubular body in a distal direction.

[0023] In some examples, the extended configuration, the distal end of the most distally positioned additional tubular body defines the distal end of the radial stabilizer, and wherein, in the contracted configuration, the distal end of the first tubular body defines the distal end of the radial stabilizer.Attorney Docket No.: THVDL-23911WO01

[0024] In some examples, the plurality of tubular bodies are configured in a telescoping relationship, such that, in the extended configuration, each of the one or more additional tubular bodies is received within the distal end of a tubular body positioned proximate the one or more additional tubular bodies, and in the contracted configuration, each of the one or more additional tubular bodies is received within the first tubular body.

[0025] In some examples, the longitudinal cavity of the most distally positioned additional tubular body defines the inner diameter of the radial stabilizer.

[0026] In some examples, an outer layer is disposed radially outward of the body of the radial stabilizer.

[0027] In some examples, the inner diameter of the radial stabilizer is sized to accommodate passage of a medical device through the longitudinal cavity.

[0028] In some examples, the body of the radial stabilizer is circumferentially rigid so as to resist radially outwardly directed hoop stress.

[0029] An example method of controlling radial expansion of a sheath according to the present disclosure includes: providing a sheath including a central lumen extending therethrough, at least a portion of the sheath is configured to locally expand from an unexpanded configuration in which the central lumen has a first diameter to an expanded configuration in which the central lumen has a second diameter that is larger than the first diameter, and then locally contract at least partially back to the unexpanded configuration; and advancing a radial stabilizer onto the sheath to a location adjacent a proximal end of the sheath, the radial stabilizer having a distal end and a proximal end and a body extending therebetween, wherein the radial stabilizer extends around at least a portion of a circumference of the sheath.

[0030] In some examples, the sheath extends through a longitudinal cavity defined by the body of the radial stabilizer and has an inner diameter.

[0031] In some examples, the method further includes coupling the proximal end of the radial stabilizer to a sheath hub cap and / or a sheath hub.

[0032] In some examples, the method further includes moving the radial stabilizer from an extended configuration in which a distance between the proximal end and the distal end of the radial stabilizer defines a first length, and a contracted configuration in which the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.Attorney Docket No.: THVDL-23911WO01

[0033] In some examples, moving the radial stabilizer from the extended configuration to the contracted configuration further includes axially displacing the distal end of the radial stabilizer in a distal direction along a longitudinal axis of the sheath.

[0034] In some examples, the sheath is radially expanded.

[0035] In some examples, the radial stabilizer is biased to resist radial expansion of the sheath beyond the inner diameter of the radial stabilizer.

[0036] An example method of delivering a medical device into a blood vessel of a patient according to the present disclosure includes: providing a sheath including a central lumen extending therethrough, at least a portion of the sheath is configured to locally expand from an unexpanded configuration in which the central lumen has a first diameter to an expanded configuration in which the central lumen has a second diameter that is larger than the first diameter, and then locally contract at least partially back to the unexpanded configuration; and advancing a radial stabilizer around the sheath to a location adjacent a proximal end of the sheath, the radial stabilizer including a body having a distal end and a proximal end and defining a longitudinal cavity therethrough; wherein the radial stabilizer extends around at least a portion of a circumference of the sheath; advancing a distal end of the sheath toward a treatment site until the distal end of the radial stabilizer abuts the surface of the patient's skin; advancing a medical device through the central lumen of the sheath to the treatment site within the blood vessel, wherein advancing the medical device through the central lumen locally expands the sheath to the expanded configuration, wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond an inner diameter of the longitudinal cavity; and delivering the medical device to the treatment site.

[0037] In some examples, the radial stabilizer is movable between an extended configuration in which a distance between the proximal end and the distal end of the radial stabilizer defines a first length, and a contracted configuration in which the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.

[0038] In some examples, advancing a distal end of the sheath toward a treatment site until the distal end of the radial stabilizer abuts the surface of the patient’s skin further includes continuing to advance the distal end of the sheath toward a treatment site, thereby pressing the distal end of the radial stabilizer against the patient's skin so as to apply a proximally directed force on the distal end of the radial stabilizer.Attorney Docket No.: THVDL-23911WO01

[0039] In some examples, applying a proximally directed force on the distal end of the radial stabilizer moves the radial stabilizer from the extended configuration to the contracted configuration.

[0040] Various aspects of the examples described herein can be combined based on desired sheath system characteristics.BRIEF DESCRIPTION OF DRAWINGS

[0041] 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.

[0042] FIG. 1 is an elevation view of an expandable sheath along with an endovascular delivery apparatus for implanting a prosthetic implant.

[0043] FIG. 2 is an elevation view of an expandable sheath including an introducer locking hub, a sheath locking sleeve, and an introducer.

[0044] FIG. 3 is an elevation view of the expandable sheath of FIG. 2 along with an endovascular delivery apparatus for implanting a prosthetic implant.

[0045] FIG. 4 is an elevation view of an expandable sheath a sheath hub, an introducer locking hub, and a sheath locking sleeve of FIG. 2.

[0046] FIG. 5A is a cross-sectional view of the sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2.

[0047] 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.

[0048] FIG. 6 is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2.

[0049] FIG. 7 is a distal end view of the sheath locking sleeve of FIG. 2 and the proximal fluid seal of FIGS 5A-B.

[0050] FIG. 8A is a first elevation view of the introducer locking hub of FIG. 2 coupled to an introducer.

[0051] FIG. 8B is a second (rotated) elevation view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0052] FIG. 8C is a distal end view of the introducer locking hub of FIG. 2 coupled to the introducer.Attorney Docket No.: THVDL-23911WO01

[0053] FIG. 8D is a partial side view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0054] FIG. 8E is a partial perspective view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0055] FIG. 8F is a partial perspective view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0056] FIG. 9A is a distal end view of the introducer locking hub of FIG. 2.

[0057] FIG. 9B is a first elevation view of the introducer locking hub of FIG. 2.

[0058] FIG. 9C is a proximal end view of the introducer locking hub of FIG. 2.

[0059] FIG. 9D is a first perspective view of the introducer locking hub of FIG. 2.

[0060] FIG. 9E is a second elevation view of the introducer locking hub of FIG. 2.

[0061] FIG. 9F is a second perspective view of the introducer locking hub of FIG. 2.

[0062] FIG. 10A is a distal end view of the sheath locking sleeve of FIG. 2.

[0063] FIG. 10B is a first elevation view of the sheath locking sleeve of FIG. 2.

[0064] FIG. 10C is a proximal end view of the sheath locking sleeve of FIG. 2.

[0065] FIG. 10D is a first perspective view of the sheath locking sleeve of FIG. 2.

[0066] FIG. 10E is a second elevation view of the sheath locking sleeve of FIG. 2.

[0067] FIG. 10F is a second perspective view of the sheath locking sleeve of FIG. 2.

[0068] FIG. 11 is a side elevation cross-sectional view of a portion of the expandable sheath of FIGS. 1 and 2.

[0069] FIG. 12 is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2.

[0070] 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.

[0071] FIG. 13B is a magnified view of a portion of the braided layer of the sheath of FIGS.1 and 2.

[0072] 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 prosthetic device is advanced through the sheath.

[0073] FIG. 15 is a side view of the expandable sheath of FIGS. 1 and 2.

[0074] FIG. 16 is a magnified cross-sectional section view of the sheath of FIG. 15 along section line 16-16.

[0075] FIG. 17 is cross-sectional view of the unexpanded sheath of FIG. 16 along section line 17-17.

[0076] FIG. 18 is cross-sectional view of the unexpanded sheath of FIG. 15 along section line 18-18.Attorney Docket No.: THVDL-23911WO01

[0077] FIG. 19 is cross-sectional view of the unexpanded sheath of FIG. 15 along section line 19-19.

[0078] FIG. 20 is cross-sectional view of the expanded sheath of FIG. 15 along section line 19-19.

[0079] FIG. 21 is a side view of the expandable sheath of FIGS. 1 and 2.

[0080] FIG. 22 is a cross-sectional view of the unexpanded sheath of FIG. 21 along section line 22-22.

[0081] FIG. 23 is a cross-sectional view of the expanded sheath of FIG. 21 along section line 22-22.

[0082] FIG. 24 shows various percutaneous vascular access approaches.

[0083] FIG. 25 A is a schematic representation of a sheath extending into a patient’s vasculature during an alternative access approach.

[0084] FIG. 25B is a schematic representation of the sheath shown in 25A ballooning in response to radially outward pressure within the sheath.

[0085] FIG. 26A is a side view of a sheath assembly according to another example, the sheath assembly including an example radial stabilizer in an extended configuration.

[0086] FIG. 26B is a side view of the sheath assembly of FIG. 27A showing the radial stabilizer in a contracted configuration.

[0087] FIG. 27A is a schematic representation of an example sheath assembly extending into the patient’s vasculature, the example sheath assembly including a radial stabilizer in an extended configuration.

[0088] FIG. 27B is a schematic representation of the sheath assembly of FIG. 27A extending into the patient’s vasculature, the example sheath assembly advanced farther into the patient’s vasculature such that the radial stabilizer is in a contracted configuration.

[0089] FIG. 28A is a partial cross-sectional side view of a sheath assembly according to another example, the sheath assembly including an example radial stabilizer in an extended configuration.

[0090] FIG. 28B is a side view of the sheath assembly of FIG. 28A showing the radial stabilizer in a contracted configuration.

[0091] FIG. 29A is a side view of a sheath assembly according to another example, the sheath assembly including an example radial stabilizer in an extended configuration.

[0092] FIG. 29B is a side view of the sheath assembly of FIG. 29A showing the radial stabilizer in a contracted configuration.Attorney Docket No.: THVDL-23911WO01DETAILED DESCRIPTION

[0093] 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.

[0094] 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.

[0095] 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 unless incompatible 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.

[0096] 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, orAttorney Docket No.: THVDL-23911WO01 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.

[0097] 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.

[0098] “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.

[0099] 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.

[0100] “Axially” or “axial” as used herein refers to a direction along the longitudinal axis of the sheath.

[0101] 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.

[0102] 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 dislodgementAttorney Docket No.: THVDL-23911WOQ1 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.

[0103] 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. 5,41 1 ,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.

[0104] 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.Attorney Docket No.: THVDL-23911WO01PCT / US 2021 / 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.

[0105] FIG. 1 illustrates an exemplary sheath 8 in use with a representative delivery apparatus 10, for delivering an implant 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 are adapted to slide longitudinally relative to each other to facilitate delivery and positioning of the implant 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.

[0106] 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, 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 (implant 12) then be delivered and implanted within patient.

[0107] 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 hubAttorney Docket No.: THVDL-23911WO0120. 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.

[0108] 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. 5A 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.

[0109] 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 the sheath 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.

[0110] 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.

[0111] 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.Attorney Docket No.: THVDL-23911WO01

[0112] 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.

[0113] 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 the introducer 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.

[0114] 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.Attorney Docket No.: THVDL-23911WO01

[0115] 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.

[0116] 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.

[0117] 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.).

[0118] 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.

[0119] 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. 8,690,936Attorney Docket No.: THVDL-23911WO01 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.

[0120] 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 axially aligned 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.

[0121] 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. 5 A 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 introducerAttorney Docket No.: THVDL-23911WO01 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.

[0122] 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.

[0123] 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 distal end 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.

[0124] 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 withAttorney Docket No.: THVDL-23911WO01 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.

[0125] 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.

[0126] 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 angled guide 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.

[0127] 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 theAttorney Docket No.: THVDL-23911WO01 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.

[0128] 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.

[0129] 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.

[0130] 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 1 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.Attorney Docket No.: THVDL-23911WO01

[0131] As illustrated in FIGS. 8A-9F, the outer surface of the introducer locking hub body 32 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.

[0132] 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.).

[0133] 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 / 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.

[0134] 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.

[0135] 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 layer), 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 layer) disposed around and radially outward of the third layer 106. In the illustrated configuration, the inner layer 102Attorney Docket No.: THVDL-23911WO01 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.

[0136] 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.

[0137] 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.

[0138] 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 112. 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.

[0139] 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 facilitateAttorney Docket No.: THVDL-23911WO01 insertion of the sheath 8 into a patient’s vessel, reducing potential damage. Examples of suitable hydrophilic coatings include the Harmony™ 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, poly vinylidene 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. Tn 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.

[0140] 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. For example, 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 110B 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 examplesAttorney Docket No.: THVDL-23911WO01 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.

[0141] 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.

[0142] 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 the braided 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 someAttorney Docket No.: THVDL-23911WO01 examples, the elastic third layer 106 can also be radially outward of the polymeric outer layer 108.

[0143] 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.

[0144] 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 layer 106 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.Attorney Docket No.: THVDL-23911WO01

[0145] FIG. 14 illustrates radial expansion of the sheath 8 as a prosthetic device (for example, implant 12) is passed through the sheath 8 in the direction of arrow 132 (for example, distally). As the prosthetic device (implant 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 (implant 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.

[0146] 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 inner layer 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.

[0147] 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 (implant 12) moves distally through the sheath 8, the portion of the sheath immediately proximal to the prosthetic device (for example, implant 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 prostheticAttorney Docket No.: THVDL-23911WO01 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.

[0148] 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.

[0149] 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.

[0150] 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 layerAttorney Docket No.: THVDL-23911WO01202, 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.

[0151] 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.

[0152] 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™ 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, poly vinylidene fluoride), are also suitable for use with the sheath 8.

[0153] 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, suchAttorney Docket No.: THVDL-23911WO01 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.

[0154] 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.

[0155] 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 can be 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 line section 22-22 in FIG. 21) can have a different configuration.

[0156] 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 layerAttorney Docket No.: THVDL-23911WO01204 is spaced apart from a second edge 225 of the outer layer 204 so as not to form a continuous layer.

[0157] 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 layer 204 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.

[0158] 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 largerAttorney Docket No.: THVDL-23911WO01 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.

[0159] 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.

[0160] 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 tip portion 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).

[0161] 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.

[0162] FIGS. 22 and 23 illustrate cross-sectional views of the sheath 8 taken along the strain relief layer 26 at section line l- 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.Attorney Docket No.: THVDL-23911WO01

[0163] 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 he 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.

[0164] 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.

[0165] 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).

[0166] 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.Attorney Docket No.: THVDL-23911WO01

[0167] 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.

[0168] 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.

[0169] 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 the sheath 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.

[0170] 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 extendAttorney Docket No.: THVDL-23911WO01 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.Attorney Docket No.: THVDL-23911WO01

[0175] 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.

[0176] 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 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 herein. Materials for the strain relief layer 26 can be selected such that it impedes expansion of the underlying layers of the sheath 8.

[0177] 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 a thickness 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.

[0178] 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.

[0179] 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 layerAttorney Docket No.: THVDL-23911WO0126 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.

[0180] 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.

[0181] 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 be adjusted 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.

[0182] 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 femoralAttorney Docket No.: THVDL-23911WO01 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 and in the example sheath 308 shown in FIG. 25A. This can produce stress at the access point, leading to sheath kinking and overall poor usability.

[0183] Moreover, introducer sheaths are subjected to radially outward pressure (for example, blood pressure) from within the sheath. As described herein, various layers of the introducer sheath can be made of a compliant material to allow for easy expansion of the various layers. For the portion of the introducer sheath that is inserted within a patient’s body, radially outward pressure from within the introducer sheath is balanced by the blood pressure within the patient’s blood vessel. However, where portions of the introducer sheath extend outside of the patient’s body, as in alternative access approaches, the introducer sheath may not be suitable to resist radially outward pressures. Rather, high enough pressures within the introducer sheath can cause portions of the introducer 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 (see, for example, ballooning of example sheath 308 in FIG. 25B).

[0184] Attempts to prevent ballooning by increasing the hoop strength of the introducer sheath (for example, by stiffening one or more layers) may have the undesirable effect of increasing the amount of push force needed to advance a delivery system through the introducer sheath, making the procedure more difficult for the clinician.

[0185] Disclosed herein are sheath assemblies 300 that address these problems by controlling radial expansion of the sheath 308 along a length of the sheath 308 that extends outside of the patient. This length can vary depending on patient size and anatomy, as well as physician preferences. 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). Specifically, the present disclosure provides an example sheath assembly 300 that can be used to maintain homeostasis of sheath 308 during alternative access procedures by resisting radial expansion of the portion of the sheath 308Attorney Docket No.: THVDL-23911WO01 that remains outside the patient’ s body during the procedure, while not adversely affecting the push force needed to expand the sheath 308.

[0186] The sheath assemblies 300 are described in reference to FIGS. 26A-29B and include a sheath 308 for deploying a medical device. As shown, a radial stabilizer 360 is disposed at least partially around a portion of the sheath 308. Advantageously, the radial stabilizer 360 resists radial expansion of the portion of the sheath 308 around which the radial stabilizer 360 extends, thereby reducing the risk that the sheath 308 balloons when subjected to radially outward pressures from within the sheath 308.

[0187] It is contemplated herein that the sheath assemblies 300 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 (implant 12). Furthermore, it is contemplated that the sheath assemblies 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.

[0188] FIGS. 26A-26B illustrate side views of an example sheath assembly 300 including a sheath 308 that has a distal end 310 and a proximal end 312 with a central lumen 314 extending therebetween along a longitudinal axis X. As shown, the sheath 308 has a length LTOTAL corresponding to a total length of the sheath measured between the distal end 310 of the sheath 308 and the proximal end 312 of the sheath 308. As further described herein, during alternative access procedures, a portion of the sheath 308 having a length less than LTOTAL remains outside the patient’s body.

[0189] FIGS. 26A-26B also show the radial stabilizer 360 extending around the sheath 308. As shown, the radial stabilizer 360 has a distal end 366 and a proximal end 368. A body 362 of the radial stabilizer 360 extends a distance between the proximal end 368 of the radial stabilizer 360 and the distal end 366 of the radial stabilizer 360. Is shown in the illustrated example, the distance between the proximal end 368 of the radial stabilizer 360 and the distal end 366 of the radial stabilizer 360 is less than a distance between the proximal end 312 of the sheath 308 and the distal end 310 of the sheath 308.

[0190] Furthermore, as shown in FIGS. 26A-26B, the body 362 of the radial stabilizer 360 defines a longitudinal cavity 364 extending longitudinally therethrough. As shown, the longitudinal cavity 364 is sized and configured to receive the sheath 308, which extends through the longitudinal cavity 364. Specifically, the longitudinal cavity 364 of the radial stabilizer 360 has an inner diameter IDRS selected to limit the extent to which the sheath 308 extending through the longitudinal cavity 364 can expand. In the illustrated example, theAttorney Docket No.: THVDL-23911WO01 body 362 of the radial stabilizer 360 is circumferentially rigid such that the inner diameter IDRS remains constant even as the sheath 308 expands and applies a radially outward force on the radial stabilizer 360. Advantageously, the illustrated circumferentially rigid radial stabilizer 360 thereby prevents the sheath 308 from radially expanding beyond the inner diameter IDRS of the radial stabilizer 360 along the first length LRS of the of the radial stabilizer 360 by resisting radially outwardly directed hoop stress applied by the sheath 308.

[0191] Furthermore, as described herein, it is desirable for sheaths to be expandable so as to accommodate passage of medical devices therethrough, where the medical devices have widths larger than the internal diameters of the sheaths. However, the ballooning effect described herein can be more pronounced in sheaths that are designed to be more compliant. Accordingly, by providing radial support against excess expansion of the sheath 308, incorporation of the radial stabilizer 360 into sheath assembly 300 confers the added advantage of allowing use of more flexible / compliant sheaths 308. Thus, the sheath 308 can be made more flexible / compliant so as to accommodate larger medical devices.

[0192] In each of the example sheath assemblies 300 provided herein, the inner diameter IDRS is sized to receive a medical device (such as prosthetic device / implant 12) and permit advancement of the medical device through the length of the radial stabilizer 360. Accordingly, the inner diameter IDRS is small enough to prevent ballooning of the sheath 308, but large enough to permit passage of the medical device therethrough. Though the radial stabilizer 360 shown in this example is circumferentially rigid so as to resist radial expansion, the radial stabilizer 360 remains flexible such that it can deflect away from the longitudinal axis X. Advantageously, this flexibility facilitates bending of the radial stabilizer 360 so that it can adapt to bending of the sheath 308 during insertion into a patient.

[0193] In further examples, the radial stabilizer 360 can be formed from an elastic material. For example, the elastic material can include any elements of the strain relief layer 26 described herein. By forming the radial stabilizer 360 from an elastic material that is biased to exert a radially inward force, the radial stabilizer 360 can limit radial expansion of the sheath 308 by applying a radially inwardly directed force on the sheath 308 that gradually increases as the sheath 308 expands against it. In these examples, the inner diameter IDRS of the longitudinal cavity 364 is not rigidly fixed. Instead, the resistance to radial expansion supplied by the radial stabilizer 360 may be controlled by varying the physical or material properties of the radial stabilizer 360. For example, the radial stabilizer 360 may be formed from fewer / thinner layers or more compliant materials to permit greater radial expansion of the sheath 308 or may be formed from more / thicker layers or more rigid materials to moreAttorney Docket No.: THVDL-23911WO01 closely constrain radial expansion of the sheath 308. Advantageously, an elastic radial stabilizer 360 can have a variable diameter that may initially be small and that increases in response to expansion of the sheath 308.

[0194] In the illustrated example sheath assembly 300, the radial stabilizer 360 extends around the entire circumference of the sheath 308. Specifically, the body 362 of the radial stabilizer 360 is in the form of a spring. As shown, coils 370 of the spring-shaped radial stabilizer 360 extend all the way around the circumference of the sheath 308.Advantageously, where the radial stabilizer 360 extends all the way around the circumference of the sheath 308, the radial stabilizer 360 is able to provide a more constant allowance for radial expansion of the sheath 308 disposed within the longitudinal cavity 364. Accordingly, increasing the number of coils 370 or the spacing between adjacent coils 370 in the springlike radial stabilizer 360 can provide more constant radial expansion of the sheath 308 by preventing the sheath 308 from expanding between gaps formed between adjacent coils 370. Additionally, the radial stabilizer 360 provides the added advantage of protecting the sheath 308 from inadvertent damage such as punctures. Thus, examples of the radial stabilizer 360 that extend around a greater portion of the sheath 308 provide greater protection. Furthermore, configurations where the radial stabilizer 360 extends all the way around the circumference of the sheath 308 reduce the risk that the radial stabilizer 360 may inadvertently become uncoupled from the sheath 308 during use.

[0195] However, in further examples, in further examples, the radial stabilizer 360 can extend around only a portion of the circumference of the sheath 308 such that a longitudinal slit or gap is defined between opposing ends of the radial stabilizer 360. In these examples, the radial stabilizer 360 can be formed from an elastic material that allows the radial stabilizer 360 to flex or otherwise elastically deform so as to so that a width of the slit or gap is increased, thereby allowing the radial stabilizer 360 to be advanced over the sheath 308. For example, the radial stabilizer 360 can be loaded onto the sheath 308 by flexing and / or bending the radial stabilizer 360 to increase the width of the slit or gap so that it is greater than the outer diameter of the sheath 308. After advancing the radial stabilizer 360 over the sheath 308, the width of the slit or gap in the radial stabilizer 360 then returns to a width less than the width of the sheath 308 so that the radial stabilizer 360 will not release from the sheath 308 in a transverse direction. In further examples, the body 362 can include longitudinally extending sections that are pivotably coupled at a hinge. Pivoting the longitudinally extending sections of the body 362. Accordingly, in these examples, the radial stabilizer 360 can be advanced over the sheath by pivoting longitudinally extending sectionsAttorney Docket No.: THVDL-23911WO01 of the body 362 away from each other relative to the longitudinal axis X. The radial stabilizer 360 can then be closed around the sheath by pivoting longitudinally extending sections of the body 362 toward each other relative to the longitudinal axis X. Advantageously, where the radial stabilizer 360 is deformable or otherwise pivotably openable, it is possible to load the radial stabilizer 360 onto the sheath 308 after the sheath 308 is inserted into a patient’s body.

[0196] As further described herein, the sheath 308 can be inserted into a patient to deliver a medical device to a treatment site. In some examples, the sheath 308 can be advanced into the patient’s such that a portion of the sheath 308 is received within the patient’s body. Accordingly, the distal end 366 of the radial stabilizer 360 can contact the surface of the patient’s and apply a distally-directed axial force thereon. As shown in FIGS. 26A-26B, a contact surface 380 is disposed at the distal end 366 of the radial stabilizer 360. Advantageously, the contact surface 380 is distally-facing and configured to distribute the distally-directed axial force applied by the radial stabilizer 360 against the body of the patient across a broader surface of the patient’s skin. For example, the contact surface 380 can be an annular ring extending around the circumference of the sheath 308. In the illustrated example, the contact surface 380 is a planar contact surface 380 formed as a separate member that is coupled to the distal end 366 of the radial stabilizer 360. For example, the contact surface 380 can be coupled to the distal end 366 of the radial stabilizer 360 by at least one of a press fit, an interference fit, a snap fit, a weld, an adhesive, or any other mechanical and / or chemical fastener. In further examples, the contact surface 380 can be formed by the coils 370 of the spring-like radial stabilizer 360 terminating in a shape (for example, an annular ring) that is approximately perpendicular relative to the patient’s skin surrounding the location at which the sheath 308 enters the patient’s body.

[0197] In the example illustrated in FIGS. 26A-26B, the radial stabilizer 360 is axially offset relative to the distal end 310 of the sheath 308. Specifically, the example radial stabilizer 360 is disposed adjacent the proximal end 312 of sheath 308. In particular, the proximal end 368 of the radial stabilizer 360 is disposed adjacent the proximal end 312 of the sheath 308.

[0198] In the example shown, a sheath hub 340 is positioned at the proximal end 312 of the sheath and a sheath hub cap 320 couples the proximal end 312 of the sheath 308 to the sheath hub 340. In this example, the proximal end 368 of the radial stabilizer 360 is directly coupled to the sheath hub cap 320 by an interference fit. For example, in some implementations, the proximal end 368 of the radial stabilizer 360 can flare outward to couple with a portion of the sheath hub cap 320 that has a diameter greater than inner diameter IDRS of the radialAttorney Docket No.: THVDL-23911WO01 stabilizer 360 when not subjected to outwardly-directed radial stress. In further examples, the radial stabilizer 360 may be directly or indirectly coupled to any one of the proximal end 312 of the sheath 308, the sheath 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. Advantageously, securing the radial stabilizer 360 at or near the proximal end 312 of the sheath 308 positions the radial stabilizer 360 at an axial location along the length of the sheath that is left extending outside the body of the patient during alternative access procedures. Thus, these configurations of the radial stabilizer 360 provide radial stability for the sheath 308 along regions of the sheath 308 that are most likely to “balloon” during use.

[0199] As illustrated in FIGS. 26A-26B, the position of at least a portion of the radial stabilizer 360 is axially displaceable along the longitudinal axis X. For example, the distal end 366 of the radial stabilizer 360 can be axially displaceable along the longitudinal axis X.

[0200] FIG. 26A shows a side view of an example sheath assembly 300 with the radial stabilizer 360 in an extended configuration, in which the distance between the proximal end 368 of the radial stabilizer 360 and the distal end 366 of the radial stabilizer 360 defines a first length LRS. FIG. 26B shows a side view of the example sheath assembly 300 with the radial stabilizer 360 moved into a contracted configuration, in which the distance between the proximal end 368 of the radial stabilizer 360 and the distal end 366 of the radial stabilizer 360 defines a second length LRS’ that is less than the first length LRS. Accordingly, the distance between the proximal end 368 and the distal end 366 of the radial stabilizer 360 is axially adjustable along the longitudinal axis X of the sheath 308. As shown, moving the radial stabilizer 360 from the extended configuration to the contracted configuration axially the distal end 366 of the radial stabilizer 360 along the longitudinal axis X while the position of the proximal end 368 of the radial stabilizer 360 remains substantially stationary. Advantageously, control over the axial position of the radial stabilizer 360 facilitates adjusting the region of the sheath 308 around which the radial stabilizer 360 extend even as the effective length LEFF of the sheath 308 inserted into the patient (and thus the length of the sheath 308 remaining outside the patient) is varied.

[0201] It is desirable for the radial stabilizer 360 to accommodate a large change in the distance between the proximal end 312 of the sheath 308 and the incision site. Accordingly, it is desirable that the second length LRS’ be significantly less than the first length LRS and the total length LTOTAL- In the example illustrated in FIG. 26B, the second length LRS’ is less than 50% of the total length LTOTAL of the sheath 308. Furthermore, the body 362 of the example radial stabilizer 360 is shown to have a spring-like shape. In this example, the spacingAttorney Docket No.: THVDL-23911WO01 between adjacent coils 370 of the spring-like radial stabilizer 360 decreases as the radial stabilizer 360 moves from the extended configuration to the contracted configuration. Accordingly, the radial stabilizer 360 can provide increasingly uniform resistance to radial expansion as the proportional coverage of the radial stabilizer 360 over the external section of the sheath 308 becomes greater.

[0202] Because the radial stabilizer 360 is able to move between the extended configuration and the contracted configuration, the length of the radial stabilizer 360 can vary in accordance with the portion of the total length LTOTAL of the sheath 308 that is outside of the patient. In other words, as an effective length of the sheath LEFF that is inserted into the patient increases, the length LRS of the radial stabilizer 360 decreases a corresponding amount (to LRS’). In this way, the length of the radial stabilizer 360 is responsive to the length of sheath 308 that is inserted into the patient and matches the length of the sheath 308 remains outside the patient (and is therefore subject to “ballooning”) during alternative access procedures. Advantageously, this behavior enables the radial stabilizer 360 to provide continuous resistance to radial expansion of the sheath 308 even as the effective length LEFF of the sheath 308 inserted into the patient (and thus the length of the sheath 308 remaining outside the patient) is varied.

[0203] In the example illustrated in FIGS. 26A-26B, the body 362 of the radial stabilizer 360 is formed as a single unitary piece that is resiliently compressible. However, in some examples further described herein (for example, FIGS. 28A and 28B), the body 362 can comprise a plurality of bodies.

[0204] In various examples, the extent to which the radial stabilizer 360 is axially contractable can be controlled by adjusting the spring constant of the spring-like stabilizer body 362. For example, the material / and or physical characteristics of the spring-like radial stabilizer 360 can be tailored to give the spring-like radial stabilizer 360 a relatively low spring constant, thereby increasing compliance of the radial stabilizer 360 and increasing the difference between the first length LRS and the second length LRS’ . In further examples, the material / and or physical characteristics of the spring-like radial stabilizer 360 can be tailored to give the spring-like radial stabilizer 360 a relatively high spring constant, thereby decreasing compliance of the radial stabilizer 360 and decreasing the difference between the first length L S and the second length LRS’. In some examples, the spring constant can vary axially along the body 362 of the spring-like radial stabilizer 360 such that some regions of the radial stabilizer 360 are more axially contracted than other regions of the radial stabilizer 360. In spring-like radial stabilizers 360, parameters including gauge of the coils 370,Attorney Docket No.: THVDL-23911WO01 material tensile strength, and number of coils 370 per unit length of the radial stabilizer 360 can affect the spring constant.

[0205] FIGS. 27A and 27B illustrate an example sheath assembly 300 being inserted into a patient’s body. As shown, the radial stabilizer 360 includes a spring-like radial stabilizer 360 analogous to the radial stabilizer 360 described with reference to FIGS. 26A and 26B. As shown, the spring-like radial stabilizer 360 is axially contractable along the longitudinal axis X. Specifically, FIG. 27A shows the radial stabilizer 360 in the extended configuration and FIG. 27B shows the radial stabilizer 360 in the contracted configuration. As the spring-like radial stabilizer 360 moves from the extended configuration to the contracted configuration, the spring-like radial stabilizer 360 compresses. Compression of the spring-like radial stabilizer 360 builds potential energy that contributes to the distally-directed axial force exerted by the radial stabilizer 360 onto the surface of the patient’s skin. As described herein and shown in FIGS. 27A and 27B, a contact surface 380 disposed at the distal end 366 of the radial stabilizer 360 distributes this distally-directed axial force across a broader surface of the patient’s skin, thereby reducing local trauma where the radial stabilizer 360 contacts the patient’s body.

[0206] FIGS. 28A-28B illustrate an example sheath assembly 300 including a radial stabilizer 360 that is segmented into a plurality of bodies extending along the longitudinal axis X of the radial stabilizer 360. The plurality of bodies includes a first body 375 adjacent the proximal end 368 of the radial stabilizer 360 and one or more additional bodies 375’. In example illustrated in FIGS. 28A-28B, each body of the plurality of bodies 375-375’ are tubular-shaped, having a distal end 376 and a proximal end 378 and defining a longitudinal cavity 379-379’ therethrough. However, in further examples, the plurality of bodies 375-375’ can have any cross-sectional shape that is able to accommodate the sheath 308 in an unexpanded configuration and resist subsequent radial expansion of the sheath 308 beyond a predefined inner diameter (IDRS). Furthermore, the combination of the longitudinal cavities 379-379’ of each of the tubular bodies form the longitudinal cavity 364 of the radial stabilizer 360.

[0207] In the example illustrated in FIG. 28 A, the radial stabilizer 360 includes 5 bodies (1 first body 375 and 4 additional bodies 375’). As shown, each of the plurality of bodies 375- 375’ can overlap another body. In the illustrated example, the plurality of bodies 375-375’ are sized and configured such that any given body can be received within any relatively proximate body, such as the body positioned directly proximate the given body. Specifically, in the illustrated example, the first body 375 is sized and configured to receive an adjacentAttorney Docket No.: THVDL-23911WO01 additional body 375’ disposed directly distal to the first body 375. Similarly, the additional body 375’ disposed directly distal to the first body 375 is sized and configured to receive another additional body 375’ disposed directly distal to it. Thus, each of the one or more additional bodies 375’ are displaceable relative to the first body 375 along the longitudinal axis X. Additionally, each of the one or more additional bodies 375’ can be received within the first body 375. The sheath 308 extends through the longitudinal cavities 379-379’ each of the plurality of bodies 375-375’. FIG. 28 includes a partial cross-sectional view showing the most distally positioned additional body 375’ in cross-section. As illustrated, the inner diameter (IDRS) of the radial stabilizer 360 corresponds to the inner diameter of the longitudinal cavity 379’ of the most distally positioned additional body 375’ (in other words, the additional body 375’ with the smallest inner diameter).

[0208]

[0209] FIG. 28A shows a side view of an example sheath assembly 300 with the radial stabilizer 360 in an extended configuration such that each of the plurality of bodies are axially displaced relative to one another. In other words, each of the one or more additional bodies 375’ is received within the distal end 376 of a tubular body positioned proximate the one or more additional bodies 375’. For example, in the extended configuration, each of the one or more additional bodies 375’ are axially displaced relative to the first tubular body 375 in a distal direction such that the distance between the proximal end 378 of the first body 375 and the distal end 376 of the most distally positioned additional body 375’ defines a first length LRS of the radial stabilizer 360. As shown, the proximal end 378 of the first body 375 defines the proximal end 368 of the radial stabilizer 360 and the distal end 376 of the most distally positioned additional body 375’ defines the distal end 366 of the radial stabilizer 360.

[0210] Furthermore, as shown, the proximal end 368 of the radial stabilizer 360 is coupled to the sheath hub cap 320. This coupling can include any of the attributes described herein with respect to couplings of the spring-like radial stabilizer 360 of FIGS. 26A-26B. Though not explicitly shown, the example radial stabilizer 360 illustrated in FIGS. 28A-28B can also include the contact surface 380 as described herein with respect to couplings of the springlike radial stabilizer 360 of FIGS. 26A-26B.

[0211] FIG. 28B shows a side view of an example sheath assembly 300 with the radial stabilizer 360 in a contracted configuration such that each of the additional bodies 375’ move in a proximal direction. Accordingly, each sequentially distal additional tubular body 375’ is sized to be received within all of the preceding tubular bodies 375-375’ positioned proximal to it.Attorney Docket No.: THVDL-23911WO01

[0212] In the illustrated examples, each of the additional bodies are received within the longitudinal cavity 379 of the first body 375 such that the distance between the proximal end 378 of the first body 375 and the distal end 376 of first body 375 defines a second length LRS’ of the radial stabilizer 360. Thus, the proximal end 378 of the first body 375 defines the proximal end 368 of the radial stabilizer 360 and the distal end 376 of the first body 375 defines the distal end 366 of the radial stabilizer 360.

[0213] This configuration allows the radial stabilizer 360 to move between the extended configuration and the contracted configuration by telescoping adjacent bodies of the plurality of bodies 375-375’ along the longitudinal axis X, as shown in FIGS. 28A-B. Specifically, the one or more additional bodies 375’ are axially displaced proximally toward the first body 375 to move the radial stabilizer 360 from the extended configuration to the contracted configuration. Advantageously, this behavior facilitates adjusting the region of the sheath 308 around which the radial stabilizer 360 extends so as to provide continuous resistance to radial expansion around the portion of the sheath 308 that extends outside the patient’s body even as the effective length LEFF of the sheath 308 inserted into the patient (and thus the length of the sheath 308 remaining outside the patient) is varied.

[0214] FIGS. 29A-29B illustrate an example sheath assembly 300 having a radial stabilizer 360 similar to that described herein with respect to FIGS. 26A-26B. However, the radial stabilizer 360 further includes an outer layer 390. As shown, the outer layer 390 is disposed radially outward of the body 362 of the radial stabilizer 360. In the illustrated example, the outer layer 390 is deformable along the longitudinal axis X. Advantageously, the outer layer 390 forms a protective cover over the radial stabilizer 360 and is capable of longitudinally expanding along with the radial stabilizer 360 as the radial stabilizer 360 moves between extended and contracted configurations. In further examples, the outer layer 390 may include one or more folds or corrugations that help the outer layer 390 expand and contract such that the length of the outer layer 390 is capable of adjusting to match the length of the radial stabilizer 360. Like the radial stabilizer 360 itself, the outer layer 390 provides that added advantage of protecting the sheath 308 from inadvertent damage such as punctures.

[0215] In the example illustrated in FIGS. 29A-29B, the outer layer 390 extends around an entire outer surface of the radial stabilizer 360. However, in further examples, the outer layer 390 may optionally extend around only a portion of the radial stabilizer 360. In some examples, the outer layer 390 is formed from an elastic material that is biased to resist radial expansion. Accordingly, in response to outwardly-directed radial forces exerted by the radial stabilizer 360 (and the sheath 308 therein), the outer layer 390 can apply an inwardly-directedAttorney Docket No.: THVDL-23911WO01 radial force, thereby resisting radial expansion of the radial stabilizer 360 and the sheath 308 extending therethrough.

[0216] The outer layer 390 can be coupled to the radial stabilizer 360 by various means, so long as the coupling permits the outer layer 390 to move between the extended and contracted configurations along with the radial stabilizer 360 over which it extends. For example, the outer layer 390 can be coupled to the radial stabilizer 360 by at least one of a chemical bond, weld, and / or adhesive.

[0217] A method of controlling the radial expansion of the example sheath 308 is described herein. While this example is described in reference to the sheath 308 provided in FIGS. 26A-29B, it is contemplated that a corresponding method may be used to control the radial expansion of any sheath described herein.

[0218] As described herein, in some instances, the distance within the patient between the incision site and treatment site is greater than the length of the sheath 308. In such cases, the excess length of the sheath remains outside the patient / exterior to the incision site. As described herein, the portion of the sheath 308 that extends outside of the patient’s body is subject to internal pressure from within the sheath 308 that can result in unwanted “ballooning” of the sheath, among other challenges. Accordingly, in some implementations, it is desirable to control radial expansion of the sheath 308 along a length of the sheath 308 that extends outside of the patient. Positioning a radial stabilizer 360 as depicted in FIGS. 26A-29B around at least a portion of a circumference of the sheath 308 resists radial expansion of the sheath 308 beyond the inner diameter IDRS of the radial stabilizer 360. As a result, the sheath 308 is prevented from radially expanding.

[0219] The method includes providing a sheath 308 that defines a central lumen 314 extending therethrough. As provided herein, at least a portion of the sheath 308 is configured to locally expand from an unexpanded configuration, in which the central lumen 314 has a first diameter, to an expanded configuration, in which the central lumen 314 has a second diameter that is larger than the first diameter. The portion of the sheath 308 is then configured to locally contract at least partially back to the unexpanded configuration.

[0220] The method further includes positioning a radial stabilizer 360 onto the sheath 308 at a location adjacent a proximal end 312 of the sheath 308. The radial stabilizer 360 has a distal end 366, a proximal end 368, and a body 362 extending therebetween. As shown in FIGS. 26A-29B, the radial stabilizer 360 extends around at least a portion of a circumference of the sheath 308. Advantageously, the sheath 308 is thereby prevented from radially expanding beyond the body 362 of the radial stabilizer 360.Attorney Docket No.: THVDL-23911WO01

[0221] As described herein, positioning the radial stabilizer 360 onto the sheath 308 can include positioning the radial stabilizer 360 around a distal end 310 of the sheath 308 and advancing the radial stabilizer 360 over sheath 308 in a distal direction toward the proximal end 312 of the sheath 308. As shown, the body 362 of the radial stabilizer 360 can define a longitudinal cavity 364 extending therethrough, where the longitudinal cavity 364 has an inner diameter IDRS. In some examples, including the examples illustrated in FIGS. 26A- 29B, the sheath 308 extends through the longitudinal cavity 364.

[0222] In various examples, the sheath 308 can be a component of a sheath assembly 300. In example sheath assemblies 300 that include a sheath hub 340 or sheath hub cap 320, the proximal end 368 of the radial stabilizer 360 can be coupled to the sheath hub 340 and / or the sheath hub cap 320. Advantageously, coupling the radial stabilizer 360 to the sheath hub 340 / sheath hub cap 230 anchors the position of the proximal end 368 of the radial stabilizer 360 so that radial stability is provided over the proximal end 312 of the sheath 308 and / or over the sheath 308 adjacent the proximal end 312 of the sheath 308, which include portions of the sheath 308 most likely to experience undesirable ballooning during use.

[0223] As illustrated in FIGS. 26A-29B, the method can further include moving the radial stabilizer 360 between an extended configuration and a contracted configuration. In the extended configuration, the distance between the proximal end 368 of the radial stabilizer 360 and the distal end 366 of the radial stabilizer 360 defines a first length LRS. In the contracted configuration, the distance between the proximal end 368 of the radial stabilizer 360 and the distal end 366 of the radial stabilizer 360 defines a second length LRS’ that is less than the first length L S. By moving between the extended configuration and the contracted configuration, the distal end 366 of the radial stabilizer 360 can be displaced in a distal direction along the longitudinal axis X of the sheath 308. Advantageously, control over the axial position of the radial stabilizer 360 facilitates adjusting the region of the sheath 308 around which the radial stabilizer 360 extends even as the effective length LEFF of the sheath 308 inserted into the patient (and thus the length of the sheath 308 remaining outside the patient) is varied.

[0224] In some examples, moving the radial stabilizer 360 from the extended configuration to the contracted configuration can further include engaging a contact surface 80 disposed at the distal end 366 of the radial stabilizer 360 against the surface of the patient’s skin. Advancement of the sheath assembly 300 distally into the patient’s vasculature causes the surface of the patient’ s skin to apply a proximally-directed axial force against the contact surface 380. Accordingly, the contact surface, which is coupled to the distal end 366 of theAttorney Docket No.: THVDL-23911WO01 radial stabilizer 360, transmits the proximally-directed axial force into the radial stabilizer, thereby causing the radial stabilizer 360 to move incrementally towards the contracted configuration.

[0225] With the radial stabilizer 360 positioned around the sheath 308 and extended to a desired length, the sheath 308 can then be radially expanded. As provided herein, the radial stabilizer 360 can be biased to resist radial expansion of the sheath 308 disposed therein.

[0226] The devices depicted in FIGS. 26A-29B are used to control radial expansion of a sheath 308, for example, when a length of the sheath 308 extends outside of a patient. Such methods can be helpful when utilizing alternatives to the femoral approach, such as, but not limited to carotid, subclavian, and axillary approaches as shown in FIG. 24. FIG. 24 shows sheaths introduced at the femoral access site Sr, the carotid access site Sc, the axillary access site Sa, and the subclavian access site Ss. The methods disclosed herein can also be useful when treating a child or a smaller adult, or in veterinary settings, where the provided sheath 308 is longer than necessary and would otherwise excessively extend outside the patient’s body, risking damage to the sheath 308 and / or trauma to the patient anatomy.

[0227] A method of delivering a medical device (such as implant 12) into a blood vessel of a patient is described herein. While this example is described in reference to the sheath 308 provided in FIGS. 26A-29B and previously described with respect to the method of controlling the radial expansion of a sheath, it is contemplated that a corresponding method may be used to deliver a medical device using any sheath described herein.

[0228] As provided herein, the sheath 308 is configured to facilitate passage of the delivery apparatus 10 / medical device through an incision site and to a treatment site within a patient’s body. Accordingly, the method includes advancing the distal end 310 of the sheath 308 toward a treatment site until the distal end 366 of the radial stabilizer 360 abuts the surface of the patient’s skin. In some examples, abutting the surface of the patient’s skin with the distal end 366 of the radial stabilizer 360 can include engaging a contact surface 380 disposed at the distal end 366 of the radial stabilizer 360 against the surface of the patient’s skin.

[0229] As provided herein, continuing to advance the distal end 310 of the sheath 308 toward the treatment site presses the distal end 366 of the stabilizer 360 against the patient’s skin, thereby applying an incrementally increasing proximally-directed axial force on the distal end 366 of the radial stabilizer 360. This proximally-directed axial force moves the distal end 366 of the radial stabilizer 360 from the extended configuration, in which the distance between the proximal end 368 and the distal end 366 of the radial stabilizer 360 defines the first length LRS, to a contracted configuration in which the distance between theAttorney Docket No.: THVDL-23911WO01 proximal end 368 and the distal end 366 of the radial stabilizer 360 is a second length LRS- that is less than the first length LRS.

[0230] Because the radial stabilizer 360 is able to move between the extended configuration and the contracted configuration, the length of the radial stabilizer 360 can vary in accordance with the portion of the total length LTOTAL of the sheath 308 that is outside of the patient. Thus, advancing the distal end 310 of the sheath 308 toward the treatment site increases an effective length of the sheath LEFF that is inserted into the patient. In response, the length LRS of the radial stabilizer 360 decreases a corresponding amount to LRS’. In this way, the length of the radial stabilizer 360 is responsive to the length of sheath 308 that is inserted into the patient and matches the length of the sheath 308 remains outside the patient (and is therefore subject to “ballooning”) during alternative access procedures.

[0231] As provided herein, a medical device (implant 12) and / or delivery apparatus 10 can then be advanced into the sheath 308. As the medical device (implant 12) and / or delivery apparatus 10 are advanced through the sheath 308, they exert an outwardly directed radial force against the central lumen 314 of the sheath 308, causing a portion of the sheath 308 proximate the medical device (implant 12) and / or delivery apparatus 10 to locally expand from the unexpanded configuration to the expanded configuration.

[0232] As provided herein, the radial stabilizer 360 is biased to resist radial expansion of the sheath 308 beyond the inner diameter IDRS of the longitudinal cavity 364 of the radial stabilizer 360. Specifically, the radial stabilizer 360 resists radial expansion of the sheath 308 along the portion of the sheath that remains outside of the patient as the sheath 308 moves distally or proximally within the patient’s vasculature.

[0233] As the medical device (implant 12) and / or delivery apparatus 10 passes through the central lumen 314 of the sheath 308, a corresponding portion of the sheath 308 locally contracts at least partially back to the unexpanded configuration when the medical device (implant 12) has passed. When used to deliver a medical device (implant 12) within a patient, the medical device (implant 12) is then passed through the distal opening of the sheath 308 and is delivered to the treatment site. The position of the medical device (implant 12) can be moved or adjusted until the medical device (implant 12) is adequately positioned within the patient.

[0234] With the medical device delivered to the treatment site, any delivery apparatus 10 and / or components coupled to the medical device (implant 12) are then removed from the medical device (implant 12) and withdrawn from / through the central lumen 314 of the sheath 308. In some examples, withdrawing the medical device (implant 12) from the central lumenAttorney Docket No.: THVDL-23911WO01314 of the sheath 308 further includes locally contracting the sheath 308 at least partially back to the unexpanded configuration as the medical device (implant 12) passes through the central lumen 314.

[0235] The sheath 308 is then withdrawn from the patient’s blood vessel and the opening in the blood vessel and skin closed.

[0236] In reference to the sheath 8 of FIGS. 11-23, once the radial stabilizer 360 is positioned around the sheath 308 and moved from the extended configuration to the expanded configuration, the medical device and delivery apparatus can then be advanced into the sheath 8, particularly the portion of the sheath 8 including the strain relief layer 26. In some examples, the medical device is contracted or compressed radially as it passes through the strain relief layer 26, from the proximal portion 242, through the tapered portion 248 and into the smaller diameter distal portion 246.

[0237] As the medical device and delivery apparatus are advanced through the strain relief layer 26, they exert an outwardly directed radial force against the central lumen of the sheath 8, causing the strain relief layer 26 (and corresponding portion of the sheath 8) proximate the medical device / delivery apparatus to locally expand from an unexpanded configuration to an expanded configuration.

[0238] The medical device is then advanced beyond the distal end 27 of the strain relief layer 26, into the lumen of the sheath 8 beyond the strain relief layer 26. As the medical device is advanced through the sheath 8 beyond the strain relief layer 26, the sheath 8 locally expands from the unexpanded configuration (FIGS. 11-13 A, 17-19) to the expanded configuration (FIGS. 14, 20) at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the inner layer / central lumen 212 of the sheath 8. In some examples, the sheath 8 corresponds to the layered sheath 8 structure described in reference to FIGS. 11-23. The sheath 8 includes an inner layer and / or outer layer, and a folded portion, for example, ridges 126 and valleys 128 of the fourth (outer) layer 108 (FIGS. 11-14), and folded portion 218 of the inner layer 202 (FIGS. 15-23). Locally expanding the lumen of the layered sheath 8 causes a length of the folded portion to at least partially unfold. Similarly, locally contracting the sheath 8 at least partially back to the unexpanded configuration causes a length of the folded portion to urge back to a folded configuration. For example, in reference to the sheath 8 of FIGS. 15-23, the outer layer is a discontinuous outer layer and includes an overlapping portion (for example, overlapping portion 220) and an underlying portion (for example, underlying portion 222). With the sheath 8 in the unexpanded configuration, the folded portion 218 is disposed between theAttorney Docket No.: THVDL-23911WO01 overlapping portion 220 overlaps the underlying portion 222 (FIG. 19). As the sheath 8 locally expands to the expanded configuration, a length of the overlapping portion 220 moves circumferentially with respect to the underlying portion 222, at least partially unfolding the folded portion 218. As illustrated in FIG. 20, when the layered sheath is fully expanded, the inner layer 202 extends into the gap 232 formed between the longitudinal edges of the overlapping portion 220 and the underlying portion 222 of the outer layer 204.

[0239] As the medical device passes through the lumen of the sheath 8 / strain relief layer 26, the sheath 8 / strain relief layer 26 locally contracts at least partially hack to the unexpanded configuration when the medical device has passed. When used to deliver a medical device within a patient, the medical device is then passed through the distal opening of the sheath 8 and delivered to the treatment site. The position of the medical device can be moved or adjusted until the medical device is adequately positioned within the patient.

[0240] With the medical device delivered to the treatment site, any delivery apparatus / components coupled to the medical device are then removed from the medical device and withdrawn from / through the central lumen 212 of the sheath 8. In some examples, withdrawing the medical device from the central lumen 212 of the sheath 8 further includes locally contracting the sheath 8 at least partially back to the unexpanded configuration as the medical device passes through the central lumen 212, for example, by the radially inward force of an elastic outer layer 250 / outer jacket provided over the sheath 8.

[0241] The sheath 8 is then withdrawn from the patient’s blood vessel and the opening in the blood vessel and skin closed.

[0242] In some examples, the sheath 8 includes an elastic outer layer 250 that extends at least partially over the outer layer and / or the strain relief layer 26. The elastic outer layer 250 locally expands and contracts as the medical device is advanced through the lumen of the sheath 8. In some examples, the elastic outer layer 250 urges the various layers of the sheath 8 to an unexpanded configuration.

[0243] The medical device described herein can include a prosthetic device mounted in a radially crimped state on a delivery apparatus, and the act of advancing the prosthetic device through the lumen of the sheath 8 comprises advancing the delivery apparatus and the prosthetic device through lumen of the sheath 8 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 a treatment site within the patient. In some examples, the prosthetic heart valve is mounted on a balloon catheter of the deliveryAttorney Docket No.: THVDL-23911WO01 apparatus as the prosthetic heart valve is advanced through the sheath 8. In some examples, the sheath 8 is inserted into a femoral artery of the patient.

[0244] In view of the many possible examples to which the principles of the disclosed disclosure can be applied, it should be recognized that the illustrated examples 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.

[0245] Exemplary Aspects

[0246] 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.

[0247] Example 1: A sheath assembly comprising: a sheath for deploying a medical device; and a radial stabilizer extending around at least a portion of the sheath, wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond an inner diameter of the radial stabilizer.

[0248] Example 2: A sheath assembly comprising: a sheath for deploying a medical device, the sheath having a distal end and a proximal end with a central lumen extending therebetween; and a radial stabilizer having a distal end and a proximal end and a body extending therebetween, wherein the proximal end of the radial stabilizer is disposed adjacent the proximal end of the sheath, wherein the body defines a longitudinal cavity having an inner diameter, wherein the radial stabilizer extends around at least a portion of a circumference of the sheath such that the sheath extends through the longitudinal cavity, wherein a distance between the proximal end and the distal end of the radial stabilizer is less than a distance between the proximal end and distal end of the sheath, , and wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond the inner diameter of the radial stabilizer.

[0249] Example 3: The sheath assembly according to any example herein, particularly example 2, wherein the proximal end of the radial stabilizer is coupled to the proximal end of the sheath and / or a sheath hub cap and / or a sheath hub, wherein the sheath hub cap and the sheath hub are coupled to the proximal end of the sheath.Attorney Docket No.: THVDL-23911WO01

[0250] Example 5: The sheath assembly according to any example herein, particularly examples 2-4, wherein the distal end of the radial stabilizer comprises a distally-facing contact surface.

[0251] Example 6: The sheath assembly according to any example herein, particularly example 5, wherein the contact surface comprises an annular ring.

[0252] Example 7 : The sheath assembly according to any example herein, particularly examples 2-6, wherein the distance between the proximal end and the distal end of the radial stabilizer is axially adjustable along the longitudinal axis of the sheath between an extended configuration and a contracted configuration.

[0253] Example 8: The sheath assembly according to any example herein, particularly example 7, wherein, in the extended configuration, the distance between the proximal end and the distal end of the radial stabilizer defines a first length, and in the contracted configuration, the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.

[0254] Example 9: The sheath assembly according to any example herein, particularly examples 7-8, wherein the proximal end of the radial stabilizer is substantially stationary.

[0255] Example 10: The sheath assembly according to any example herein, particularly examples 8-9, wherein the second length of the radial stabilizer is less than or equal to 50% the length of the sheath.

[0256] Example 11 : The sheath assembly according to any example herein, particularly examples 2-10, wherein the body of the radial stabilizer is a spring comprising a plurality of coils.

[0257] Example 12: The sheath assembly according to any example herein, particularly examples 2-11, wherein the radial stabilizer comprises a plurality of tubular bodies extending along the longitudinal axis of the radial stabilizer, the plurality of tubular bodies comprising a first tubular body and one or more additional tubular bodies, wherein each tubular body comprises a distal end and a proximal end and defines a longitudinal cavity, wherein the combination of the longitudinal cavities of each of the tubular bodies form the longitudinal cavity of the radial stabilizer.

[0258] Example 13: The sheath assembly according to any example herein, particularly example 12, wherein each of the one or more additional tubular bodies is displaceable relative to the first tubular body along the longitudinal axis.Attorney Docket No.: THVDL-23911WO01

[0259] Example 14: The sheath assembly according to any example herein, particularly examples 12-13, wherein the proximal end of the first tubular body defines the proximal end of the radial stabilizer.

[0260] Example 15: The sheath assembly according to any example herein, particularly examples 13-14, wherein, when the radial stabilizer is in the extended configuration, the one or more additional tubular bodies are axially displaced relative to the first tubular body in a distal direction.

[0261] Example 16: The sheath assembly according to any example herein, particularly example 15, wherein, in the extended configuration, the distal end of the most distally positioned additional tubular body defines the distal end of the radial stabilizer, and wherein, in the contracted configuration, the distal end of the first tubular body defines the distal end of the radial stabilizer.

[0262] Example 17: The sheath assembly according to any example herein, particularly examples 13-16, wherein the plurality of tubular bodies are configured in a telescoping relationship, such that, in the extended configuration, each of the one or more additional tubular bodies is received within the distal end of a tubular body positioned proximate the one or more additional tubular bodies, and in the contracted configuration, each of the one or more additional tubular bodies is received within the first tubular body.

[0263] Example 18: The sheath assembly according to any example herein, particularly examples 15-17, wherein the longitudinal cavity of the most distally positioned additional tubular body defines the inner diameter of the radial stabilizer.

[0264] Example 19: The sheath assembly according to any example herein, particularly examples 2-18, wherein an outer layer is disposed radially outward of the body of the radial stabilizer.

[0265] Example 20: The sheath assembly according to any example herein, particularly examples 2-19, wherein the inner diameter of the radial stabilizer is sized to accommodate passage of a medical device through the longitudinal cavity.

[0266] Example 21: The sheath assembly according to any example herein, particularly examples 2-20, wherein the body of the radial stabilizer is circumferentially rigid so as to resist radially outwardly directed hoop stress.

[0267] Example 22. A method of controlling radial expansion of a sheath, the method including: providing a sheath including a central lumen extending therethrough, at least a portion of the sheath is configured to locally expand from an unexpanded configuration in which the central lumen has a first diameter to an expanded configuration in which theAttorney Docket No.: THVDL-23911WO01 central lumen has a second diameter that is larger than the first diameter, and then locally contract at least partially back to the unexpanded configuration; and advancing a radial stabilizer onto the sheath to a location adjacent a proximal end of the sheath, the radial stabilizer having a distal end and a proximal end and a body extending therebetween, wherein the radial stabilizer extends around at least a portion of a circumference of the sheath.

[0268] Example 23: The method according to any example herein, particularly example 22, wherein the sheath extends through a longitudinal cavity defined by the body of the radial stabilizer and has an inner diameter.

[0269] Example 24: The method according to any example herein, particularly examples 22-23, further comprising coupling the proximal end of the radial stabilizer to a sheath hub cap and / or a sheath hub.

[0270] Example 25: The method according to any example herein, particularly examples 22-24, further comprising moving the radial stabilizer from an extended configuration in which a distance between the proximal end and the distal end of the radial stabilizer defines a first length, and a contracted configuration in which the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.

[0271] Example 26: The method according to any example herein, particularly example 25, wherein moving the radial stabilizer from the extended configuration to the contracted configuration further comprises axially displacing the distal end of the radial stabilizer in a distal direction along a longitudinal axis of the sheath.

[0272] Example 27 : The method according to any example herein, particularly examples 22-26, wherein the sheath is radially expanded.

[0273] Example 28: The method according to any example herein, particularly examples 22-27, wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond the inner diameter of the radial stabilizer.

[0274] Example 29. A method of delivering a medical device into a blood vessel of a patient, comprising: providing a sheath including a central lumen extending therethrough, at least a portion of the sheath is configured to locally expand from an unexpanded configuration in which the central lumen has a first diameter to an expanded configuration in which the central lumen has a second diameter that is larger than the first diameter, and then locally contract at least partially back to the unexpanded configuration; and advancing a radial stabilizer around the sheath to a location adjacent a proximal end of the sheath, the radial stabilizer comprising a body having a distal end and a proximal end and defining aAttorney Docket No.: THVDL-23911WO01 longitudinal cavity therethrough; wherein the radial stabilizer extends around at least a portion of a circumference of the sheath; advancing a distal end of the sheath toward a treatment site until the distal end of the radial stabilizer abuts the surface of the patient’s skin; advancing a medical device through the central lumen of the sheath to the treatment site within the blood vessel, wherein advancing the medical device through the central lumen locally expands the sheath to the expanded configuration, wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond an inner diameter of the longitudinal cavity; and delivering the medical device to the treatment site.

[0275] Example 30: The method according to any example herein, particularly example 29, wherein the radial stabilizer is movable between an extended configuration in which a distance between the proximal end and the distal end of the radial stabilizer defines a first length, and a contracted configuration in which the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.

[0276] Example 31 : The method according to any example herein, particularly example 30, wherein advancing a distal end of the sheath toward a treatment site until the distal end of the radial stabilizer abuts the surface of the patient's skin further comprises continuing to advance the distal end of the sheath toward a treatment site, thereby pressing the distal end of the radial stabilizer against the patient’s skin so as to apply a proximally directed force on the distal end of the radial stabilizer.

[0277] Example 32: The method according to any example herein, particularly example 31, wherein applying a proximally directed force on the distal end of the radial stabilizer moves the radial stabilizer from the extended configuration to the contracted configuration.

[0278] 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

Attorney Docket No.: THVDL-23911WO01CLAIMSWhat is claimed is:

1. A sheath assembly comprising: a sheath for deploying a medical device, the sheath having a distal end and a proximal end with a central lumen extending therebetween; a radial stabilizer having a distal end and a proximal end and a body extending therebetween, wherein the proximal end of the radial stabilizer is disposed adjacent the proximal end of the sheath, wherein the body defines a longitudinal cavity having an inner diameter, wherein the radial stabilizer extends around at least a portion of a circumference of the sheath such that the sheath extends through the longitudinal cavity, wherein a distance between the proximal end and the distal end of the radial stabilizer is less than a distance between the proximal end and distal end of the sheath, and wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond the inner diameter of the radial stabilizer.

2. The sheath assembly of claim 1, wherein the proximal end of the radial stabilizer is coupled to the proximal end of the sheath and / or a sheath hub cap and / or a sheath hub, wherein the sheath hub cap and the sheath hub are coupled to the proximal end of the sheath, wherein the distal end of the radial stabilizer comprises a distally-facing contact surface.

3. The sheath assembly according to any one of claims 1-2, wherein the distance between the proximal end and the distal end of the radial stabilizer is axially adjustable along a longitudinal axis of the sheath between an extended configuration and a contracted configuration.

4. The sheath assembly of claim 3, wherein, in the extended configuration, the distance between the proximal end and the distal end of the radial stabilizer defines a first length, and in the contracted configuration, the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.Attorney Docket No.: THVDL-23911WO015. The sheath assembly of any one of claims 1-4, wherein the body of the radial stabilizer is a spring comprising a plurality of coils.

6. The sheath assembly of any one of claims 1-5, wherein the radial stabilizer comprises a plurality of tubular bodies extending along a longitudinal axis of the radial stabilizer, the plurality of tubular bodies comprising a first tubular body and one or more additional tubular bodies, wherein each tubular body comprises a distal end and a proximal end and defines a longitudinal cavity, wherein the combination of the longitudinal cavities of each of the tubular bodies form the longitudinal cavity of the radial stabilizer.

7. The sheath assembly of claim 6, wherein the distance between the proximal end and the distal end of the radial stabilizer is axially adjustable along a longitudinal axis of the sheath between an extended configuration and a contracted configuration, wherein each of the one or more additional tubular bodies is displaceable relative to the first tubular body along the longitudinal axis, wherein, when the radial stabilizer is in the extended configuration, the one or more additional tubular bodies are axially displaced relative to the first tubular body in a distal direction.

8. The sheath assembly of claim 7, wherein, in the extended configuration, the distal end of a most distally positioned additional tubular body defines the distal end of the radial stabilizer, and wherein, in the contracted configuration, the distal end of the first tubular body defines the distal end of the radial stabilizer.

9. The sheath assembly of any one of claims 7-8, wherein the plurality of tubular bodies are configured in a telescoping relationship, such that, in the extended configuration, each of the one or more additional tubular bodies is received within the distal end of a tubular body positioned proximate the one or more additional tubular bodies, and in the contracted configuration, each of the one or more additional tubular bodies is received within the first tubular body.Attorney Docket No.: THVDL-23911WO0110. The sheath assembly of any one of claims 1-9, wherein an outer layer is disposed radially outward of the body of the radial stabilizer.

11. The sheath assembly of any one of claims 1-10, wherein the body of the radial stabilizer is circumferentially rigid so as to resist radially outwardly directed hoop stress.

12. A method of controlling radial expansion of a sheath, the method including: providing a sheath including a central lumen extending therethrough, at least a portion of the sheath is configured to locally expand from an unexpanded configuration in which the central lumen has a first diameter to an expanded configuration in which the central lumen has a second diameter that is larger than the first diameter, and then locally contract at least partially back to the unexpanded configuration; and advancing a radial stabilizer onto the sheath to a location adjacent a proximal end of the sheath, the radial stabilizer comprising a body having a distal end and a proximal end and defining a longitudinal cavity therethrough, wherein the radial stabilizer extends around at least a portion of a circumference of the sheath.

13. The method of claim 12, wherein the sheath extends through a longitudinal cavity defined by the body of the radial stabilizer and has an inner diameter.

14. The method of any one of claims 12-13, further comprising coupling the proximal end of the radial stabilizer to a sheath hub cap and / or a sheath hub.

15. The method of any one of claims 12-14, further comprising moving the radial stabilizer from an extended configuration in which a distance between the proximal end and the distal end of the radial stabilizer defines a first length, and a contracted configuration in which the distance between the proximal end and the distal end of the radial stabilizer defines a second length that is less than the first length.

16. The method of claim 15, wherein moving the radial stabilizer from the extended configuration to the contracted configuration further comprises axially displacing the distal end of the radial stabilizer in a distal direction along a longitudinal axis of the sheath.Attorney Docket No.: THVDL-23911WO0117. The method of any one of claims 12-16, further including: radially expanding the sheath, where wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond an inner diameter of the radial stabilizer.

18. A method of delivering a medical device into a blood vessel of a patient, comprising: providing a sheath including a central lumen extending therethrough, at least a portion of the sheath is configured to locally expand from an unexpanded configuration in which the central lumen has a first diameter to an expanded configuration in which the central lumen has a second diameter that is larger than the first diameter, and then locally contract at least partially back to the unexpanded configuration; advancing a radial stabilizer around the sheath to a location adjacent a proximal end of the sheath, the radial stabilizer comprising a body having a distal end and a proximal end and defining a longitudinal cavity therethrough; wherein the radial stabilizer extends around at least a portion of a circumference of the sheath; advancing a distal end of the sheath toward a treatment site until the distal end of the radial stabilizer abuts the surface of the patient’s skin; advancing a medical device through the central lumen of the sheath to the treatment site within the blood vessel, wherein advancing the medical device through the central lumen locally expands the sheath to the expanded configuration, wherein the radial stabilizer is biased to resist radial expansion of the sheath beyond an inner diameter of the longitudinal cavity; and delivering the medical device to the treatment site.

19. The method of claim 18, wherein the radial stabilizer is movable between an extended configuration in which a distance between the proximal end and the distal end of the radial stabilizer defines a first length, and a contracted configuration in which the distance between the proximal end and the distal end of the radial stabilizer is a second length that is less than the first length, wherein advancing a distal end of the sheath toward a treatment site until the distal end of the radial stabilizer abuts the surface of the patient’s skin further comprises continuing to advance the distal end of the sheath toward a treatment site, thereby pressing the distal endAttorney Docket No.: THVDL-23911WO01 of the radial stabilizer against the patient’s skin so as to apply a proximally directed force on the distal end of the radial stabilizer.

20. The method of claim 19, wherein applying a proximally directed force on the distal end of the radial stabilizer moves the radial stabilizer from the extended configuration to the contracted configuration.

Images