Expandable sheaths

Abstract

An expandable sheath (140) for delivering a prosthetic valve, comprising an elongated body having a distal end portion (143) and a proximal end portion (144), the elongated body including a braided layer (154) comprising a first set of filaments (160A) and a second set of filaments (160B) braided together in a biaxial braid.

Description

EXPANDABLE SHEATHS AND INTRODUCER SYSTEMSCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent No. 63 / 777,339, filed March 25, 2025, the contents of which are incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present application is directed to an expandable sheath and introducer for use with catheter-based technologies for repairing and / or replacing heart valves, as well as for delivering an implant, 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 to reach target destinations rather than surgically opening a target site. There are many types of diseases or 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 guidewire is used to track to the correct locationwithin 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 (for example, the femoral artery). 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 / proximal hub or handle 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. However, portions of the sheath resist expansion requiring higher push forces for advancement of the delivery apparatus and implant to the treatment location. Increased push forces are also experienced when the sheath, delivery apparatus and / or implant encounter a narrowed or hardened blood vessel, a calcific lesion, or other blockage / occlusion that may impede delivery of the medical device to the treatment location.SUMMARY

[0007] In example sheath system, the structure of at the proximal end of the sheath is complicated by the need to provide hemostasis between the sheath and the subject and the risk of ballooning or damage to the sheath due to the subject’s internal blood pressure and the inadvertent flow of blood into the portion of the sheath external to the subject. Entry site bleeding is known to cause pain and prolong hospitalization time. Additionally, it is difficult to provide universal length sheath that will prevent hemostasis due to differences in subject anatomy, for example, the thickness of the fat layer at the insertion site.

[0008] Accordingly, there remains a need for improvements to the devices, systems and methods of introducing expandable sheaths that are customizable to accommodate variations in subject anatomy while also ensuring hemostasis at the treatment site.

[0009] Aspects of the present expandable sheath and introducer system can minimize damage to the sheath at the coupling point with the sheath hub assembly. The present expandable sheath and corresponding manufacturing and assembly methods help to increase radialstrength of a proximal end of the sheath. The present example sheaths also helps to optimize radial strength of the proximal end without reducing an axial strength of the sheath.

[0010] In one of its basic configurations, the present disclosure provides a sheath system for deploying a medical device including a braided layer and a reinforced proximal end portion where the sheath is coupled to a sheath hub assembly. A reinforcing element is coupled to the braided layer along the reinforced proximal end portion. 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] In some implementations, the present disclosure provides an expandable sheath for delivering a prosthetic valve. The expandable sheath comprises an elongated body having a distal end portion and a proximal end portion. The elongated body includes a braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid.

[0012] In some implementations, the first and second set of filaments intersect at an intersection axis extending along a length of the elongated body,

[0013] In some implementations, the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and the intersection axis.

[0014] In some implementations, the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first or second set of filaments and the intersection axis.

[0015] In some implementations, the first angle is greater than the second angle.

[0016] In some implementations, the present disclosure provides an expandable sheath for delivering a prosthetic valve. The expandable sheath comprises an elongated body having a distal end portion and a proximal end portion. The elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid.

[0017] In some implementations, a helical wire is coupled to the proximal end portion of the elongated body. The helical wire increases a radial strength of the proximal end portion.

[0018] In some implementations, the present disclosure provides an expandable sheath for delivering a prosthetic valve. The expandable sheath comprises an elongated body having adistal end portion and a proximal end portion. The elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together.

[0019] In some implementations, an intersection between the first and second set of filaments defines a junction, and wherein, along the proximal end portion, the junction includes a junction locking material configured to restrict axial movement first and second set of filaments of the braided layer while allowing pivotable movement of the junction and radial expansion of the proximal end portion.

[0020] In some implementations, the present disclosure provides a sheath system comprising a radially expandable sheath defining a central lumen extending therethrough and a dilator sized and configured to be received within the central lumen of the sheath. The dilator includes an elongated dilator shaft including an expansion element provided thereon. The central lumen is movable 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, larger diameter.

[0021] In some implementations, the elongated dilator shaft includes a plurality of indica markings corresponding to insertion depth of the dilator within the sheath.

[0022] In some implementations, the techniques described herein relate to a method of delivering a medical device through a sheath, the method comprising: providing an expandable sheath including a braided layer; introducing a medical device into a proximal end of a central lumen of the expandable sheath; advancing a medical device through the central lumen of the expandable sheath causing the sheath to locally expand from an unexpanded configuration toward expanded configuration at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the central lumen; and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen.

[0023] In some implementations, the techniques described herein relate to a method of delivering a medical device through a sheath, the method comprising: providing an expandable sheath including a braided layer; introducing the dilator into a proximal end of a central lumen of the sheath; advancing the dilator through a proximal portion of the sheath such that the expansion element provided on the dilator exerts an outwardly directed radial force against the central lumen and causing the proximal portion of the sheath proximate the expansion element to locally expand from an unexpanded configuration toward an expanded configuration; locally contracting the proximal portion of the sheath towards the unexpanded configuration as the expansion element passes through a corresponding portion of the centrallumen of sheath; removing the dilator from the central lumen of the sheath; introducing a medical device into the proximal end of the central lumen of the expandable sheath; advancing a medical device through the central lumen of the expandable sheath causing the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the central lumen; and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen.

[0024] In some implementations, the techniques described herein relate to a method of inserting a medical device into a blood vessel of a subject (e.g., a living subject, a simulation), the method comprising: inserting a radially expandable sheath according to any one of claims 1-30 at least partially into the blood vessel of a subject; introducing a medical device into a proximal end of a central lumen of the sheath; advancing the medical device through the sheath; and advancing the medical device beyond a distal opening in the sheath to a treatment site within the blood vessel.

[0025] Various aspects of the examples described above can be combined based on desired sheath system characteristics.BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a side view of an exemplary delivery apparatus for a cardiovascular prosthetic device.

[0027] FIG. 2 is a side view of an exemplary introducer device assembly.

[0028] FIG. 3 is a side view of an expandable sheath that can be used in combination with the introducer device assembly of FIG. 2.

[0029] FIG. 4 is a side cross-sectional view of a portion of the expandable sheath of FIG. 3.

[0030] FIG. 5 is a magnified side view of a portion of the expandable sheath of FIG. 3.

[0031] FIG. 6A is a magnified view of a portion of the expandable sheath of FIG. 3 with the outer layer removed for purposes of illustration.

[0032] FIG. 6B is a magnified side view of a portion of the braided layer of the sheath of FIG. 3.

[0033] FIG. 7 is a magnified side view of a portion of the expandable sheath of FIG. 3 illustrating expansion of the sheath as a prosthetic device is advanced through the sheath.

[0034] FIG. 8 is a side view of an expandable sheath including a reinforced proximal end portion according to another implementation of the disclosure, which can be used in combination with the introducer device assembly of FIG. 2.

[0035] FIG. 9 A is a magnified side view of a portion of the braided layer of a proximal end of the sheath of FIG. 8.

[0036] FIG. 9B is a magnified side view of a portion of the braided layer of a distal end of the sheath of FIG. 8.

[0037] FIG. 10 is a side view of an expandable sheath including a reinforced proximal end portion according to another implementation of the disclosure, which can be used in combination with the introducer device assembly of FIG. 2

[0038] FIG. 11 is a side view of an expandable sheath including a reinforced proximal end portion according to another implementation of the disclosure that can be used in combination with the introducer device assembly of FIG. 2

[0039] FIG. 12 is a magnified side view of a portion of the braided layer of a proximal end of the sheath of FIG. 11, illustrating a junction of the braided layer with a junction locking material.

[0040] FIG. 13 is a side view of the expandable sheath of FIG. 2 and an example dilator.

[0041] FIG. 14 is a side view of a dilator according to an implementation of the disclosure.

[0042] FIG. 15 is a side view of a dilator according to another implementation of the disclosure.

[0043] In the drawings, like reference numbers and designations indicate like elements.DETAILED DESCRIPTION

[0044] 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.

[0045] 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 aspects, alone and in various combinations and sub-combinations with one another. Thedisclosed 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.

[0046] Features, integers, characteristics, steps, 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 aspects. 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.

[0047] The techniques, methods, processes, operations, steps, etc. described or suggested herein or in the references incorporated herein, and any methods of using the systems, assemblies, apparatuses, devices, etc. herein, can be performed on a living subject (e.g., human, other animal, etc.) or on a simulation (e.g., a cadaver, cadaver heart, simulator, imaginary person, etc.). When performed on a simulation, the body parts, e.g., heart, tissue, valve, etc., can be assumed to be simulated or can optionally be referred to as “simulated” (e.g., simulated heart, simulated tissue, simulated valve, etc.) and can optionally comprise computerized and / or physical representations of body parts, tissue, etc. The term “simulation” covers use on a cadaver, computer simulator, imaginary person (e.g., if they are just demonstrating in the air on an imaginary heart), etc.

[0048] Any of the various systems, assemblies, devices, components, apparatuses, etc. in this disclosure can be sterilized (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.) to ensure they are safe for use with patients, and the methods herein can comprise (or additional methods comprise or consist of) sterilization of the associated system, device, component, apparatus, etc. (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.).

[0049] 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 extentnecessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0050] 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.

[0051] As used herein, the term “proximal” refers to a position, direction, or portion of a device that is closer to the user and further away from the implantation site. As used herein, the term “distal” refers to a position, direction, or portion of a device that is further away from the user and closer to the implantation site. Thus, for example, proximal motion of a device is motion of the device away from the implantation site and toward the user (for example, out of the subject body), while distal motion of the device is motion of the device away from the user and toward the implantation site (for example, into the subject’s body). The terms “longitudinal” and “axial” refer to an axis extending in the proximal and distal directions, unless otherwise expressly defined.

[0052] 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. Further, the term “coupled” generally means physically, mechanically, chemically, magnetically, and / or electrically coupled or linked and does not exclude the presence of intermediate elements between the coupled or associated items absent specific contrary language.

[0053] The expandable introducer sheaths and related componentry described herein can be used to deliver a prosthetic device through a subject’s vasculature to a procedure site within the body. The sheath can be constructed to be highly expandable and radially collapsible.Disclosed aspects of the expandable sheath can minimize trauma to the vessel by reducing push forces required to advance the sheath through the blood vessel, and / or reducing push forces required to advance a medical device and / or delivery system through the sheath. In some implementations, the expandable sheath can minimize trauma to the vessel by allowing for temporary expansion of a portion of the introducer sheath to accommodate a delivery system, followed by a return to an original diameter once the device passes therethrough.

[0054] 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 / US 2021 / 031227, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” Application No. PCT / US2021 / 031275, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” U.S. Application No. 17 / 113,268, entitled “Expandable Sheath and Method of Using the Same,” Application No.PCT / US2021 / 058247, entitled “Self-Expanding, Two Component Sheath,” Application No. PCT / US2022 / 012785, entitled “Expandable Sheath,” U.S. Patent No. 11,051,939, entitled “Active Introducer Sheath System,” Application No. PCT / US2022 / 012684, entitled “Introducer with Sheath Tip Expander,” U.S. Application No. 17 / 078,556, entitled “Advanced Sheath Patterns,” Application No. PCT / US2021 / 025038, entitled “Low temperature hydrophilic adhesive for use in expandable sheath for introducing an endovascular delivery device into a body,” Application No. PCT / US2021 / 050006, entitled “Expandable Sheath Including Reversable Bayonet Locking Hub,” U.S. Provisional Application No. 63 / 280,251, entitled “Expandable Sheath Gasket to Provide Hemostasis,” U.S. Provisional Application No. 63 / 530,144, entitled “Introducer / Dilator with Folded Balloon,” and U.S. Provisional Application No. 63 / 502,907, entitled “Lead Screw Driven Sheath Dilator,” the disclosures of which are herein incorporated by reference.

[0055] It is contemplated that the features described herein (e.g., reinforced proximal end portions) can be used in combination with any suitable sheath, including suitable sheaths set forth in any of the patent applications mentioned herein.

[0056] FIG. 1 illustrates an exemplary sheath 40 in use with a representative delivery apparatus 10, such as a prosthetic heart valve or other prosthetic implant, to a subject. The delivery apparatus 10 illustrated can generally include a steerable guide catheter 14 and a balloon catheter 16 extending through the guide catheter 14. A prosthetic device, such as a prosthetic heart valve (prosthetic device 12), can be positioned on the distal end of the balloon catheter 16. The guide catheter 14 and the balloon catheter 16 can be adapted to slide longitudinally relative to each other to facilitate delivery and positioning of a prosthetic heart valve (prosthetic device 12) at an implantation site in a subject's body.

[0057] As described in more detail herein, the sheath 40 is an elongated, expandable tube that is inserted into a vessel (for example, transfemoral vessel, femoral artery, iliac artery) by passing through the skin of subject, such that the distal end of the sheath 40 is inserted into the vessel. The sheath 40 includes a hemostasis valve and / or sealing features at the proximal end of the sheath 40, for example, in the sheath hub 24, that provide hemostasis and prevents blood leakage from the subject through the sheath 40. During the treatment procedure, the sheath 40, including an introducer 100, is advanced into the subject’s vasculature. Once positioned the introducer 100 is removed and the guide catheter 14 is inserted into / through the sheath 40, and the prosthetic heart valve (prosthetic device 12) then be delivered and implanted within subject. The guide catheter 14 includes a handle portion 18 and an elongated guide tube or shaft extending from the handle portion 18.

[0058] The prosthetic heart valve (prosthetic device 12) can be delivered into a subject’s body in a radially compressed configuration and radially expanded to a radially expanded configuration at the desired deployment site. In the illustrated example, the prosthetic heart valve (prosthetic device 12) is a plastically expandable prosthetic valve that is delivered into the subject's body in a radially compressed configuration on a balloon of the balloon catheter 16 (as shown in FIG. 1) and then radially expanded to a radially expanded configuration at the deployment site by inflating the balloon (or by actuating another type of expansion device of the delivery apparatus). Further details regarding a balloon-expandable expandable heart valve that can be implanted using the devices disclosed herein are disclosed in U.S. Patent No. 5,411,552, and also in U.S. Patent No. 9,393, 110, both of which are incorporated herein by reference. Further details regarding a plastically expandable heart valve that can be implanted using the devices disclosed herein are disclosed in U.S. Publication No.2012 / 0123529, which is incorporated herein by reference. The expandable introducer sheaths disclosed herein may also be used to deliver other types of implantable medical devices, such as self-expanding and mechanically expanding implantable heart valves, stents or filters. For example, the prosthetic heart valve (prosthetic device 12) can be a self-expandable heart valve that is restrained in a radially compressed configuration by a sheath or other component of the delivery apparatus and self-expands to a radially expanded configuration when released by the sheath or other component of the delivery apparatus. Further details regarding a selfexpandable heart valve that can be implanted using the devices disclosed herein are disclosed in U.S. Publication No. 2012 / 0239142, which is incorporated herein by reference. In still some examples, the prosthetic heart valve (prosthetic device 12) can be a mechanically expandable heart valve that comprises a plurality of struts connected by hinges or pivot joints and is expandable from a radially compressed configuration to a radially expanded configuration by actuating an expansion mechanism that applies an expansion force to the prosthetic valve. Further details regarding a mechanically expandable heart valve that can be implanted using the devices disclosed herein are disclosed in U.S. Publication No.2018 / 0153689, which is incorporated herein by reference. In still some examples, a prosthetic valve can incorporate two or more of the above-described technologies. For example, a selfexpandable heart valve can be used in combination with an expansion device to assist expansion of the prosthetic heart valve.

[0059] 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.

[0060] FIG. 2 illustrates an example of an introducer device assembly 20. The assembly 20 may include the sheath 40 and an introducer 100. The introducer 100 may be positioned within a central lumen 42 (indicated in FIG. 4) of the sheath 40, as shown in FIG. 2. An optional control housing 22 may be positioned at a proximal end of the assembly and mayinclude a sheath hub 24 and an introducer hub 30. The sheath hub 24 and introducer hub 30 may optionally couple together, as shown in FIG. 2.

[0061] The sheath 40 and introducer 100 are shown in an insertion configuration, for insertion together into the subject's vasculature. Upon insertion into the subject's vasculature, the introducer 100 may be withdrawn longitudinally from the sheath 40, leaving the sheath 40 within the subject's vasculature. Features of the sheath 40 and the introducer 100 individually are discussed below, as well as the operation of the sheath 40 and introducer 100 together.

[0062] The sheath 40 comprises an elongated body that may have a cylindrical shape. The sheath 40 has a distal end 43 and a proximal end 44, and a length LI (see FIG. 3) extending from the distal end 43 to the proximal end 44. The sheath 40 is configured to be inserted into a subject's vasculature. The sheath 40 may optionally comprise an introducer sheath that is used to introduce a delivery apparatus into the subject's vasculature.

[0063] The vasculature may comprise the blood vessels of the subject's body which may include the femoral artery or other vessels of the subject's body. The vasculature, such as the femoral artery, may be narrow or stiff, and may be difficult to easily insert a delivery apparatus therein. For example, the delivery apparatus may be larger than the vasculature, or may be unwieldy to penetrate through the skin or vasculature of the subject to pass therethrough by itself. Also, the vasculature may be too fragile to receive the delivery apparatus without use of an introducer sheath.

[0064] The sheath 40 accordingly may optionally be inserted into the subject’s vasculature prior to the delivery apparatus being introduced, to provide an entryway or guide path for the delivery apparatus 10 to introduce the delivery apparatus into the subject’s vasculature. After the sheath 40 is inserted, the sheath 40 may remain positioned within and surrounded by the subject’s vasculature. The delivery apparatus 10 may then be passed through the lumen of the sheath 40 for introduction into the subject’s body. The sheath 40 may remain in the vasculature until a desired time to remove the sheath 40.

[0065] The sheath 40 may be inserted into the vasculature percutaneously or a portion of the subject’s body may be surgically opened for the sheath 40 to access the vasculature. The delivery apparatus 10 passes through the lumen of the sheath 40 to reach a desired position in the subject's body. As shown in FIG. 1, the delivery apparatus 10 may pass through an opening at the proximal end of the sheath 40 for passage through the central lumen 42 of the sheath 40 and the vasculature of the subject. For example, in some implementations, the delivery apparatus 10 passes through an opening at the proximal end of the sheath 40 provided at the control housing 22 shown in FIG. 2.

[0066] The delivery apparatus and the assemblies disclosed herein may be used in transcatheter aortic valve implantation (TAVI). The delivery apparatus and the systems disclosed herein may be utilized for transarterial access, including transfemoral access, to a subject’s heart.

[0067] The sheath 40 may optionally include a strain relief portion 46 at the proximal end 44 of the sheath 40. The strain relief portion 46 may be sized larger than a proximate portion of the sheath 40 and may seal the entry point of the vasculature, to reduce the possibility of blood or other fluid being released between the exterior surface of the sheath 40 and the vasculature. The strain relief portion 46 provides a transition between the larger diameter proximal opening of the sheath 40 and the smaller diameter distal portion / opening of the sheath 40 as the medical device and / or introducer 100 are inserted into the central lumen 42 of the sheath 40. In some examples, a seal 48 is optionally positioned along the length of the sheath 40 to further prevent blood or other fluid flow from passing around the sheath 40 toward and out of the proximal end 44 of the sheath 40.

[0068] FIG. 3 illustrates a side view of an exemplary expandable sheath 40 that can be used in the introducer device assembly of FIG. 2. As shown in FIG. 3, the sheath hub 24 is optionally positioned at the proximal end 44 of the sheath 40. The sheath hub 24 may optionally include an internal chamber for the delivery apparatus 10 to be passed through to be delivered to the subject's vasculature. The sheath hub 24 may be configured to remain external to the subject's vasculature when the sheath 40 is inserted therein and may be configured to remain external to the subject’s skin for a percutaneous implantation of the sheath 40. The sheath hub 24 may be configured for a user (such as a surgeon) to grip to manipulate the sheath 40.

[0069] The sheath hub 24 may optionally comprise a cylindrical body and may include a coupling feature 29 for coupling the sheath hub 24 to another housing or component of the sheath system. The sheath hub 24 may optionally include a fluid port 26 for passing fluid such as blood to or from the subject's vasculature. Tubing 27 with a valve 28 may be coupled to the fluid port 26, for passing fluid through the fluid port 26 and for sealing flow of the fluid through the fluid port 26.

[0070] In some examples, the introducer sheath need not include a sheath hub 24. For example, the sheath 40 can be an integral part of a component of the delivery apparatus 10, such as the guide catheter. For example, the sheath 40 can extend from the handle portion 18 of the guide catheter. Additional examples of introducer devices and expandable sheaths can be found in U.S. Patent No. 11,273,062, which is incorporated by reference in its entirety.

[0071] FIGS. 4 and 5 illustrate a cross-sectional view and a side view, respectively, of a portion of the expandable sheath 40. As shown in FIG. 5, the sheath 40 can have a natural, unexpanded outer diameter DI. In certain examples, the expandable sheath 40 may optionally include a plurality of co-axial layers extending along at least a portion of the length LI of the sheath (FIG. 3). For example, with reference to FIG. 4, the expandable sheath 40 can include a first layer / inner layer 52 (also referred to as an inner layer), a second layer / braided layer 54 disposed around and radially outward of the inner layer 52, a third layer / elastic layer 56 disposed around and radially outward of the braided layer 54, and a fourth layer / outer layer 58 (also referred to as an outer layer) disposed around and radially outward of the elastic layer 56. In the illustrated configuration, the inner layer 52 can define the central lumen 42 extending along a central axis Cl. In some examples, the sheath 40 may optionally include the inner layer 52 without the outer layer 58, the inner layer 52 and outer layer 58 without the second and / or third layers, the second layer 54 without the third layer 56, the outer layer 58 without the inner layer 52, and / or any suitable combination of any of the first, second, third, and fourth layers, depending upon the particular characteristics desired. In some examples, the sheath 40 may optionally include one or more additional layers in combination with any of the first, second, third, and / or fourth layers. For example, the sheath 40 may comprise a scrolled inner layer and any of the first, second, third, and / or fourth layers in any suitable order. As another example, the sheath 40 may comprise a folded inner layer and any of the first, second, third, and / or fourth layers in any suitable order.

[0072] Referring to FIG. 5, when the sheath 40 is in an unexpanded state, the inner layer 52 and / or the outer layer 58 can form longitudinally-extending folds or creases such that the surface of the sheath comprises a plurality of ridges 62 (also referred to herein as “folds”). The ridges 62 can be circumferentially spaced apart from each other by longitudinally-extending valleys 64. When the sheath 40 expands beyond its natural diameter DI, the ridges 62 and the valleys 64 can level out or be taken up as the surface radially expands and the circumference increases, as further described below. When the sheath 40 collapses back to its natural diameter, the ridges 62 and valleys 64 can reform.

[0073] In some examples, the inner layer 52 and / or the outer layer 58 can comprise a relatively thin layer of polymeric material. For example, in some examples, the thickness of the inner layer 52 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 certain aspects, the thickness of the outer layer 58 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.

[0074] In some examples, the inner layer 52 and / or the outer layer 58 can comprise a lubricious, low-friction, and / or relatively non-elastic material. In particular examples, the inner layer 52 and / or the outer layer 58 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 poly ether ether ketone (PEEK). With regard to the inner layer 52 in particular, such a low coefficient of friction materials can facilitate passage of the prosthetic device through the central lumen 42. Other suitable materials for the inner and outer layers can include polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyether block amide (for example, Pebax), and / or combinations of any of the above. Some examples of a sheath 40 can include a lubricious liner on the inner surface of the inner layer 52. Examples of suitable lubricious liners include materials that can further reduce the coefficient of friction of the inner layer 52, 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.

[0075] Additionally, some examples of the sheath 40 can include an optional exterior hydrophilic coating on the outer surface of the outer layer 58. Such a hydrophilic coating can facilitate insertion of the sheath 40 into a subject’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 N.V., Heerlen, the Netherlands), as well as other hydrophilic coatings (for example, PTFE, polyethylene, polyvinylidene fluoride), are also suitable for use with the sheath 40. Such hydrophilic coatings may also be optionally included on the inner surface of the inner layer 52 to reduce friction between the sheath 40 and the delivery system 10, thereby facilitating the use and improving safety. In some examples, a hydrophobic coating, such as Perylene, may be used on the outer surface of the outer layer 58 or the inner surface of the inner layer 52 in order to reduce friction.

[0076] In certain examples, the second layer / braided layer 54 can include a braided material. FIGS. 6A and 6B illustrate the sheath 40 with the outer layer 58 removed to expose the elastic layer 56. With reference to FIGS. 6A and 6B, the braided layer 54 can comprise a plurality of members or filaments 60 (for example, metallic or synthetic wires or fibers) braided together. The braided layer 54 can have any desired number of filaments 60, whichcan be oriented and braided together along any suitable number of axes. For example, with reference to FIG. 6B, the filaments 60 can include a first set of filaments 60A oriented parallel to a first axis A, and a second set of filaments 60B oriented parallel to a second axis B. The filaments 60A and 60B can be braided together in a biaxial braid such that filaments 60 A oriented along axis A form an angle 0 with the filaments 60B 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 60 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.

[0077] The braided layer 54 can extend along substantially the entire length LI of the sheath 40, or alternatively, can extend only along a portion of the length of the sheath 40. In some examples, the filaments 60 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 some examples, the filaments 60 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 60 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 example, filaments 60 having a flat crosssection can have dimensions of 0.1 mm x 0.2 mm. However, other geometries and sizes are also suitable for certain examples. If a braided wire is used, the braid density can be varied. Some examples have a braid density of from ten picks per inch to eighty picks per inch, and can include eight wires, sixteen wires, or up to fifty-two wires in various braid patterns. In some examples, the braided layer 54 can be laser cut from a tube, or laser-cut, stamped, punched, etc., from sheet stock and rolled into a tubular configuration. The braided layer 54 can also be woven or knitted, as desired.

[0078] In some examples, the plurality of ridges 62 and valleys 64 can form between filaments of a braided layer when the sheath is in a collapsed configuration.

[0079] An elastic layer, which can be for example third layer 56, can be a resilient, elastic layer (also referred to as an elastic material layer). In certain examples, the elastic layer 56 can be configured to apply force to the underlying inner layer 52 and / or braided layer 54 in a radial direction (for example, toward the central axis Cl of the sheath) when the sheath 40 expands beyond its natural diameter by passage of the delivery apparatus through the sheath 40. Stated differently, the elastic layer 56 can be configured to apply encircling pressure to the layers of the sheath 40 beneath the elastic layer 56 to counteract expansion of the sheath 40. The radially inwardly directed force is sufficient to cause the sheath to collapse radiallyback to and / or towards (e.g., within 30%, within 20%, within 10% of) its unexpanded state after the delivery apparatus 10 is passed through the sheath 40.

[0080] In the illustrated example, the elastic layer 56 can optionally comprise one or more members configured as strands, ribbons, or bands 66 helically wrapped around the braided layer 54. For example, in the illustrated sheath 40, the elastic layer 56 comprises two elastic bands 66A and 66B wrapped around the braided layer 54 with opposite helicity, although the elastic layer 56 may comprise any number of strands, ribbons, and / or bands depending upon the desired characteristics. The elastic bands 66A and 66B 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.

[0081] In some examples, the elastic layer 56 can comprise an elastomeric material having a modulus of elasticity of 200 MPa or less. In some examples, the elastic layer 56 can comprise a material exhibiting an elongation to break of 200% or greater, or an elongation to break of 400% or greater. The elastic layer 56 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 layer 56, the sheath 40 may also include an optional elastomeric or heat-shrink tubing layer around the outer layer 58.Examples of such elastomeric layers are disclosed in U.S. Patent Nos. 9,301,841, 10,792,471, and 10,856,981, which are incorporated herein by reference. In some examples, the elastic layer 56 can also be radially outward of the polymeric outer layer 58.

[0082] In some examples, one or both of the inner layer 52 and / or the outer layer 58 can be configured to resist axial shortening of the sheath 40 when the sheath expands radially. More particularly, one or both of the inner layer 52 and / or the outer layer 58 can resist stretching against longitudinal forces caused by friction between a prosthetic device 12 and the inner surface of the sheath 40 such that the length LI remains substantially constant as the sheath 40 expands and contracts radially. As used herein with reference to the length LI of the sheath 40, the term “substantially constant” means that the length LI 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. 6B, the filaments 60A and 60B of the braided layer 54 can be allowed to move angularly relative to each other such that the angle 0 changes as the sheath 40 expands and contracts. This, in combination with thelongitudinal ridges 62 (folds) in the inner layer 52 and outer layer 58, can allow the central lumen 42 to expand as a prosthetic device is advanced through it.

[0083] In some examples, the inner layer 52 and the outer layer 58 can be heat-bonded during the manufacturing process such that the braided layer 54 and the elastic layer 56 are encapsulated between the inner layer 52 and the outer layer 58. More specifically, in certain examples, the inner layer 52 and the outer layer 58 can be adhered to each other through the spaces between the filaments 60 of the braided layer 54 and / or the spaces between the elastic bands 66. The inner layer 52 and outer layer 58 can also be bonded or adhered together at the proximal and / or distal ends of the sheath 40. In some examples, the inner layer 52 and / or outer layer 58 are not adhered to the filaments 60. In some examples, the filaments 60 to move angularly relative to each other, and relative to the inner layer 52 and outer layer 58, allowing the diameter of the braided layer 54, and thereby the diameter of the sheath 40, to increase or decrease. As the angle 0 between the filaments 60A and 60B changes, the length of the braided layer 54 can also change. For example, as the angle 0 increases, the braided layer 54 can foreshorten, and as the angle 0 decreases, the braided layer 54 can lengthen to the extent permitted by the areas where the inner layer 52 and outer layer 58 are bonded. However, in some examples, the change in length of the braided layer 54 that accompanies a change in the angle 0 between the filaments 60A and 60B does not result in a significant change in the length LI of the sheath 40 (for example, where the braided layer 54 is not adhered to the inner layer 52 and outer layer 58).

[0084] FIG. 7 illustrates radial expansion of the sheath 40 as a prosthetic device 12 is passed through the sheath 40 in the direction of arrow A (for example, distally). As the prosthetic device 12 is advanced through the sheath 40, the sheath 40 can resiliently expand to a second diameter D2 that corresponds to a size or diameter of the prosthetic device 12. As the prosthetic device 12 is advanced through the sheath 40, the prosthetic device 12 can apply longitudinal force to the sheath 40 in the direction of motion by virtue of the frictional contact between the prosthetic device 12 and the inner surface of the sheath 40. However, as noted herein, in some implementations, the inner layer 52 and / or the outer layer 58 can be optionally configured to resist axial elongation such that the length LI of the sheath 40 remains constant, or substantially constant. This can reduce or prevent the braided layer 54 from lengthening, and thereby constricting the central lumen 42.

[0085] Meanwhile, in some examples, the angle 0 between the filaments 60A and 60B can increase as the sheath 40 expands to the second diameter D2 to accommodate the prosthetic device 12. This can cause the braided layer 54 to foreshorten. However, in some examples,e.g., when the filaments 60 are not engaged or adhered to the inner layer 52 or outer layer 58, the shortening of the braided layer 54 attendant to an increase in the angle 0 does not affect or substantially affect the overall length LI of the sheath 40. Moreover, because of the longitudinally-extending ridges 62 (folds) formed in the inner layer 52 and outer layer 58, the inner layer 52 and outer layer 58 can expand to the second diameter D2 without rupturing, in spite of being relatively thin and relatively non-elastic. In this manner, the sheath 40 can resiliently expand from its natural and / or crimped diameter DI to a second diameter D2 that is larger than the diameter DI as a prosthetic device 12 is advanced through the sheath 40, without lengthening, and without constricting. Thus, the force required to push the prosthetic device 12 through the sheath 40 is significantly reduced.

[0086] Additionally, the radial expansion of the sheath 40 can be localized to the specific portion of the sheath 40 occupied by the prosthetic device 12, for example, because of a radial force applied by an elastic layer 56. For example, with reference to FIG. 7, as the prosthetic device 12 moves distally through the sheath 40, the portion of the sheath 40 immediately proximal to the prosthetic device 12 can radially collapse back towards and / or to the initial diameter DI under the influence of the elastic layer 56. The inner layer 52 and outer layer 58 can also buckle as the circumference of the sheath 40 is reduced, causing the ridges 62 and the valleys 64 to reform. This can reduce the size of the sheath 40 required to introduce a prosthetic device 12 of a given size. Additionally, the temporary, localized nature of the expansion can reduce trauma to the blood vessel into which the sheath 40 is inserted, along with the surrounding tissue, because only the portion of the sheath 40 occupied by the prosthetic device 12 expands beyond the sheath’s natural diameter and the sheath 40 collapses back towards and / or to the initial diameter once the device has passed. This limits the amount of tissue stretched in order to introduce the prosthetic device 12, and the amount of time for which a given portion of the vessel is dilated to allow the prosthetic device 12 to pass.

[0087] In addition to the advantages above, the expandable sheath 40 examples described herein can provide surprisingly superior performance relative to known introducer sheaths. For example, it is possible to use a sheath 40 configured as described herein to deliver a prosthetic device having a diameter that is two times larger, 2.5 times larger, or even three times larger than the natural outer diameter of the sheath 40. For instance, in one example, a crimped prosthetic heart valve having a diameter of 7.2 mm was successfully advanced through a sheath configured as described above and having a natural outer diameter of 3.7 mm. As the prosthetic valve was advanced through the sheath 40, the outer diameter of theportion of the sheath 40 occupied by the prosthetic valve increased to 8 mm. In other words, it was possible to advance a prosthetic device having a diameter more than two times the outer diameter of the sheath 40 through the sheath 40, during which the outer diameter of the sheath 40 resiliently increased by 216%. In another example, a sheath 40 with an initial or natural outer diameter of 4.5 mm to 5.0 mm can be configured to expand to an outer diameter of 8 mm to 9 mm.

[0088] As described herein, in some implementations the interaction between the proximal portion of the sheath and the subject anatomy complicates the ability to ensure hemostasis between the sheath and the subject. For example, changes in the shape of the sheath in response to entry forces and / or entry angle and differences between sheath and blood vessel recoil after passage of the medical device can impact sealing / hemostasis at the entry into the blood vessel.

[0089] In some examples, the sheath is inserted through an incision at the subject’s skin and into the blood vessel at an angle (for example a 30° or 45° angle), after which it bends to align with the blood vessel’s axis. In some cases, this bend can lead to braid flattening, in which the braid's cross-section becomes flattened (or C-shaped) in the region of the curve or bend. In such cases, as the sheath is no longer circular at the site of entry into the blood vessel, sealing against the blood vessel may be affected.

[0090] In other examples, sealing of the sheath against the blood vessel is impacted by the differences between sheath and blood vessel recoil. That is, after passing the prosthetic device through the sheath, the sheath tends to recoil to some degree, such that its diameter is reduced compared to the expanded diameter of the sheath. However, in some instances the blood vessel may be relatively stiff (for example, due to artery calcification), such that the blood vessel does not contract to the same extent, leaving a gap between the sheath and the blood vessel’s wall through which blood can leak.

[0091] As described herein are various example sheaths that have improved sealing of the sheath against the blood vessel. In some examples, improved sealing is provided by adjusting the braid angle between the filaments of the braid layer along the proximal portion of the sheath, incorporating a reinforcement element along the proximal portion of the sheath, and / or reinforcing the braid filament junctions along the proximal portion of the sheath.

[0092] For example, FIGS. 8-12 illustrate expandable sheaths 140, 240, 340 according to other implementations of the disclosure. Each expandable sheath 140, 240, 340 has a distal end portion 143, 243, 343 and a proximal end portion 144, 244, 344 that is reinforced (for example, a reinforced proximal end portion) with an increased radial strength compared tothe rest of the sheath 140, 240, 340. In particular, each expandable sheath 140, 240, 340 includes a reinforcing element 105, 205, 305 coupled to and / or incorporated into the braided layer 154, 254, 354 along the proximal end portion 144, 244, 344. It should be appreciated that the reinforcing elements 105, 205, 305 described in each implementation of the expandable sheaths 140, 240, 340 can be used in conjunction with any of the other reinforcing elements 105, 205, 305 in a single implementation. In other words, an expandable sheath may include any combination of the reinforcing elements 105, 205, 305 described herein, and / or any other suitable reinforcing elements.

[0093] Further, it is contemplated that the sheaths 140, 240, 340 referenced in regard to FIGS. 8-12 can include the layered sheath structure described herein in reference FIGS. 4-7, and / or any other sheath structure disclosed herein.

[0094] Now with reference to FIGS. 8, 9A and 9B, the sheath 140 includes an elongated body having a distal end portion 143 and a proximal end portion 144. The elongated body of the sheath 140 has a length L defined between the proximal and distal ends of the sheath. In some examples, the length L of the sheath is in a range from 100 cm to 150 cm. Further, the proximal end portion 144 has length L’ in a range from 60 mm to 150 mm. In some examples, the proximal end portion 144 has a length L’ of 100 mm. In some examples, the proximal end portion 144 can be 3 percent to 20 percent, 3 percent to 10 percent, 5 percent to 10 percent, or 5 percent to 15 percent of the length L of the elongated body of the sheath 140.

[0095] As described herein, in some examples, the elongated body of the sheath 140 includes a braided layer 154 comprising a plurality of members or filaments 160 (for example, metallic or synthetic wires or fibers) braided together. The braided layer 154 can have any desired number of filaments 160, which can be oriented and braided together along any suitable number of axes. In the example provided in FIGS. 9A and 9B, the braided layer 154 includes a first set of filaments 160A and a second set of filaments 160B braided together in a biaxial braid.

[0096] With reference to FIG. 9 A, the filaments 160 of the proximal end portion 144 of the sheath 140 include the first set of filaments 160A oriented parallel to a first axis A and the second set of filaments 160B oriented parallel to a second axis B. The first and second set of filaments 160 A, 160B intersect at an intersection axis 109 extending along the length L of the elongated body. In some examples, the filaments 160A and 160B are braided together in a biaxial braid such that first set of filaments 160A (for example, oriented along axis A) form an angle 9i with the intersection axis 109 and the second set of filaments 160B (for example, oriented along axis B) form an angle 02 with the intersection axis 109. As illustrated in theexample sheath 140 of FIG. 9A, in some examples, the angles 0i, 02 are equal to each other. In other examples, the angles 0i, 02 may be different. For the purpose of this disclosure, the angles 0i, O2 define a first angle defined between the first or second set of filaments 160A, 160B and the intersection axis 109. In certain examples, the angles 0i, 02 can each be from 5° to 45°, 10° to 40°, 15° to 35°, or 20° to 30°. In the illustrated example, the angles 0i, 02 are each 25°. In some examples, the combination of angles 0i, 02 can be from 10° to 90°, 20° to 80°, 30° to 50°, or 40° to 60°.

[0097] As described herein, the distal end portion 143 of the sheath 140 may comprise the section of the sheath extending between the proximal end portion 144 to the distal end of the sheath 140. In some implementations, the braided layer 154 extends along the proximal end portion 144 and distal end portion 143 of the sheath 140. In some implementations, the braided layer 154 extends along the distal end portion 143 to the distal end of the sheath 140. In some implementations, the braided layer 154 extends along the distal end portion 143 but does not extend to the distal end of the sheath 140. That is, the distal end of the braided layer 154 is spaced axially along the sheath 140 from the distal end of the sheath 140. As illustrated in FIG. 8, a portion of the braided layer 154 extending along the distal end of the sheath 140 may comprise filament loops. In some implementations, the filament loops are spaced axially from the distal end of the sheath 140. With reference to FIG. 9B, the filaments 160 along the distal end portion 143 of the sheath 140 include the first set of filaments 160 A oriented parallel to a third axis C and the second set of filaments 160B oriented parallel to a fourth axis D. The first and second set of filaments 160 A, 160B intersect at the intersection axis 109 extending along the length L of the elongated body of the sheath 140. In some examples, the filaments 160 A and 160B are braided together in a biaxial braid such that the first set of filaments 160 A (for example, oriented along axis C) form an angle 03 with the intersection axis 109 and the second set of filaments 160B (for example, oriented along axis D) form an angle 04 with the intersection axis 109. As illustrated in the example sheath 140 of FIG. 9B, the angles 03, 04 are equal to each other. In other examples, the angles 03, 04 may be different. For the purpose of this disclosure, the angles 03, 04 define a second angle defined between the first or second set of filaments 160 A, 160B and the intersection axis 109. In certain examples, the angles 03, 04 can each be from 5° to 30°, 10° to 25°, or 15° to 20°. In the illustrated example, the angles 03, 04 are each 15°. In some examples, the combination of angles 03, 04 can be from 10° to 60°, 20° to 50°, or 30° to 40°.

[0098] In order to increase the radial strength of the proximal end portion 144 of the sheath 140, the angle between filaments 160A, 160B at the proximal end portion 144 can be greaterthan the angle between filaments 160 A, 160B at the distal end portion 143. Viewed from another perspective, in the example shown, the first angle 0i, 02 is greater than the second angle 03, 04. In other words, the proximal end portion 144 having the first angle 0i, 02 that is greater than the second angle 03, 04 can define the reinforcing element 105 of the sheath 140. As a result, it is contemplated that the larger first angle 0i, 02 and increased radial strength helps to reduce the risk of braid flattening along the proximal end portion 144 of the sheath 140 without affecting the remainder of the sheath 140, while also providing greater resistance to recoil, improving sealing between the proximal end portion 144 and the blood vessel.

[0099] Now with reference to FIG. 10, the sheath 240 includes an elongated body having a distal end portion 243 and a proximal end portion 244. The elongated body of the sheath 240 has a length L defined between the proximal and distal ends of the sheath 240. As described herein, in some examples, the elongated body includes a braided layer 254 comprising a plurality of members or filaments 260 (for example, metallic or synthetic wires or fibers) braided together. The braided layer 254 can have any desired number of filaments 260, which can be oriented and braided together along any suitable number of axes. In the example provided in FIG. 10, the braided layer 254 includes a first set of filaments 260A and a second set of filaments 260B braided together. In some examples, the first and second set of filaments 260A, 260B are braided together in a biaxial braid. In some examples, the filaments 260 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.

[0100] The sheath 240 includes a reinforcing element 205 that is coupled to the braided layer 254 along the length L’ of the proximal end portion 244 of the sheath 240 (for example, to define the reinforced proximal end portion). As illustrated in FIG. 10, the reinforcing element 205 is a helical wire 209 coupled to the elongated body along the proximal end portion 244 for providing radial and axial strength to the sheath 240 and also limiting recoil after passage of the medical device through the proximal end portion 244. In some examples, as illustrated in FIG. 10, the helical wire 209 defines a helical angle ©5 measured between the sides of the helical wire 209 in an axial plane along the sheath. The helical angle 05 can range from 89 degrees to 30 degrees. In some examples, the helical angle 05 is greater than the first angle 0i, 02, 03, 04 of the first and second sets of filaments 160 A, 160B with respect to the intersection axis 109 of the filaments 160A, 160B extending longitudinally along the braided layer 254 of the sheath 140. In some examples, the helical angle O5 of the helical wire 209 can vary along the length L’ of the reinforcing element 205. In some examples the pitch the helical wire 209 can vary along length L’ of the reinforcing element 205. In some examples, various attributesof the helical wire 209 can be modified to adjust the helical wire’s 209 radial strength to resist radial collapse and axial strength to resist axial collapse. For example, the pitch, wire diameter, cross-sectional shape, and / or composition of the helical wire 209 may be modified. For example, in some implementations, the helical wire 209 is composed of a stiff spring-like material such as nitinol, nylon, and / or PET. As a result, the inclusion of the helical wire 209 increases the radial strength of the sheath 240 along the along the proximal end portion 244, reducing the risk of braid flattening while also providing greater resistance to recoil along the proximal end portion 244, improving sealing between the proximal end portion 144 and the blood vessel.

[0101] In some examples, the helical wire 209 is located between the first and second set of filaments of the filaments 260. In some examples, the helical wire 209 may be woven into or through the various sets of filaments 260 along and around the braided layer 254. In some examples, the helical wire 209 is located radially inward or radially outward of the braided layer 254. For example, the sheath 240 may have a similar construction to the sheath 40 described and illustrated in FIGS. 4 and 5. In such an example, the helical wire 209 may be positioned between any of the layers 52, 54, 56, 58 or woven into or through any of the layers 52, 54, 56, 58.

[0102] Now with reference to FIGS. 11 and 12, the sheath 340 includes an elongated body having a distal end portion (not shown) and a proximal end portion 344. As described herein, in some examples, the elongated body includes a braided layer 354 comprising a plurality of filaments 360 (for example, metallic or synthetic wires or fibers) braided together. The braided layer 354 can have any desired number of filaments 360, which can be oriented and braided together along any suitable number of axes. In the example provided in FIGS. 11 and 12, the braided layer 354 includes a first set of filaments 360A and a second set of filaments 360B braided together. In some examples, the first and second set of filaments 360A, 360B are braided together in a biaxial braid. In some examples, the filaments 360 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.

[0103] The sheath 340 includes a reinforcing element 305 that is coupled to the braided layer 354 along the length L’ of the proximal end portion 344 (for example, to define the reinforced proximal end portion). As illustrated in FIG. 12, each intersection between the first and second set of filaments 360A, 360B defines a junction 313. Along the proximal end portion 344, each junction 313 includes a junction locking material 317 configured to restrict axial movement of the first and second set of filaments 360A, 360B of the braided layer 354while allowing pivotable movement of the junction 313 and radial expansion of the proximal end portion 344. The fixed axial movement and free pivotable movement at the junction 313 helps to increase the radial and axial strength of the sheath 340 which reduces the risk of braid flattening along the proximal end portion 344, while also limiting recoil after passage of the medical device through the proximal end portion 344, ultimately improving sealing between the sheath and the blood vessel. As illustrated in the example sheath of FIGS. 11 and 12, the reinforcing element 305 is the junction locking material 317 coupled to the elongated body along the proximal end portion 244.

[0104] In some examples, the junction locking material 317 includes at least one of a mechanical coupler and a chemical coupler. In some examples, the junction locking material 317 is an adhesive and / or a polymeric material. In some examples, the junction locking material 317 includes an epoxy glue or molten polymeric material coupled to the filament junctions 313. For example, the junction locking material 317 can include thermoplastic polyurethane (TPU) or other material having a relatively high melting point to prevent it from melting and / or reflowing with the material of the sheath layers during manufacturing of the sheath 340.

[0105] In some examples, during manufacturing of the expandable sheath 340 , the proximal end portion 344 of the elongated body may be dipped into a molten form of the junction locking material 317. The material enters the junctions 313, and the junction locking material 317 is cured in the junctions 313. In some implementations, when the proximal end portion 344 of the elongated body is dipped into the junction locking material 317, the increased surface area of the junction 313 provides an increased surface area (and / or increased surface tension) at the junction 313 for collection / deposition of the junction locking material 317. The junction locking material 317 is then cured at the junctions 313 (for example, by heat treatment and / or cooling the molten joint locking material 317) to lock the junctions 313 in a manner that still allows the filaments 360 to pivot relative to each other. The junction locking material 317 maintains a radial expansion functionality of the filaments 360, but not to slide relative to each other, thereby reducing risk of the filaments 360 from flattening and / or recoiling. In other examples, the junction locking material 317 may be applied to the junctions 313 in an alternative fashion for example, by directly applying the joint locking material 317 to the junctions 313.

[0106] As described herein, in some examples, the proximal end portion of the sheath (including for example, the strain relief portion 46) has a larger diameter than the elongated body portion of the sheath, the larger diameter proximal end portion configured to sealagainst the arterial wall at the region of the arteriotomy. In some instances, subject anatomy results in a longer distance between the skin and the site of arteriotomy (for example, in an obese subject). This longer distance results in the smaller diameter portion of the sheath (in its unexpanded configuration) extending through / into the blood vessel at the arteriotomy which can in turn result in a gap forming between the sheath and the blood vessel’s wall through which blood can leak. As described herein, sealing can also be impacted due to differences between the sheath and blood vessel recoil after passage of the medical device. In some examples, a dilator including a larger diameter proximal dilating portion can be used to expand the proximal portion of the sheath. In some examples, the dilated portion of the sheath will plastically deform when expanded to maintain an expanded configuration and seal against the blood vessel at the arteriotomy throughout the procedure.

[0107] Now with reference to FIGS. 13-15, dilators 450, 550, 650 that can be advanced within the central lumen of the sheath 40 or any of the sheaths (e.g., 140, 240, 340) described herein in reference to FIGS. 1-12, are illustrated. The dilator 350 can also be used individually and / or with another expandable sheath, including expandable sheaths having different layered sheath structures than those described herein.

[0108] FIG. 13 shows a side view of sheath system 400. The sheath system 400 includes a dilator 450 and the radially expandable sheath 40. For purposes of illustrations, the sheath system 400 will be described in reference to the expandable sheath 40 illustrated in FIGS. 1-7. As described herein, in some examples, the sheath 40 includes a continuous inner layer (for example, inner layer 52) defining a central lumen 42. As described herein, the various layers of the sheath 40 and the strain relief layer 46 are configured to locally expand from an unexpanded configuration, at a first diameter, to an expanded configuration at a second, larger, diameter, due to the outwardly directed radial force exerted on the lumen of the sheath 40 (for example, inner layer 52) by the dilators 450, 550, 650 and / or a medical device (implant 12), and then locally contract at least partially back to the unexpanded configuration as the dilator 450, 550, 650 and / or medical device (implant 12) passes through the central lumen 42.

[0109] FIGS. 13-15 show side views of example dilators 450, 550, 650. The dilators 450, 550, 650 are each sized and configured to be received within the central lumen 42 of the sheath 40. The dilator 450 includes an elongated body portion 468 with an expansion element 454 provided thereon. The dilator shaft 452, when received within the sheath 40, provides longitudinal and radial stiffness to the sheath 40 while also allowing sufficient flexibility for the combined sheath 40 and the dilator 450 to be advanced through the subject’s blood vesselto the treatment location. In some examples, the dilator 450 / dilator shaft 452 has a Shore D durometer ranging from 63D to 75D. In some examples, the length of the dilator shaft 452 ranges from 25 cm to 100 cm. For example, in an example sheath system 400 used for femoral access, the length of the dilator shaft 452 is approximately 45 cm.

[0110] In some examples, the dilators 450, 550, 650 are used to pre-dilate the sheath 40 and / or vessel wall before advancing the delivery heart valve therethrough. In some examples, the sheath 40 can be pre-dilated before insertion into the subject. That is, the dilator 450, 550, 650 can be advanced into the sheath 40 while the sheath 40 is external to the subject, and the pre-dilated sheath is then introduced into the subject.

[0111] In some examples, the expansion element 454 is provided on the elongated body portion 468 of the dilator shaft 452 adjacent a distal end 472. In some examples, the diameter of the expansion element 454 can range from 12 F (4 mm) to 45 F ( 15 mm). In some examples, the expansion element 454 encloses an inflation chamber (for example, a fluidbearing chamber) for receiving the inflation fluid. In some examples, the inflation fluid includes a fluid such as saline and / or a gas. In some examples, the inflation fluid is provided to the inflation chamber via an inflation lumen in fluid communication with an inflation port 484 provided on a dilator hub 482. In some examples, upon receipt of the inflation fluid within the inflation chamber, the expansion element 454 is movable from the unexpanded configuration to the expanded configuration. Similarly, withdrawal of the inflation fluid from the inflation chamber causes the expansion element 454 to move from the expanded configuration back to the unexpanded configuration. In some examples, the volume of inflation fluid introduced into and / or withdrawn from the expansion element 454 is controlled, for example, by a mechanically or electrically controlled pump, including a computer controlled electrical pump. In the unexpanded configuration the expansion element 454 has a first diameter, and in the expanded configuration the expansion element 454 has a second, larger diameter. Upon removal of the inflation fluid from the inflation chamber, the expansion element 454 returns to the unexpanded configuration and the first diameter. In some examples, in the expanded configuration, the expansion element 454 has a larger second diameter ranging from 12 F to 45 F. For example, in the expanded configuration, the larger second diameter of the expansion element 454 can range from 12 F (4 mm) to 45 F (15 mm), and the unexpanded first diameter can range from 9 F (3 mm) to 18 F (6 mm).

[0112] As provided herein, in some implementations, the expansion element 454 and / or a second expansion element is used to pre-dilate the strain relief layer 46 and / or the proximal end portion of the sheath 40, thereby reducing the push force required to advance the deliverysystem and / or heart valve through the strain relief layer 46 and / or along the proximal end portion of the sheath. In some examples, by pre-dilating the sheath 40, the recoil of the sheath 40 can be reduced to be less than the blood vessel recoil. In other words, the sheath will maintain a larger diameter, improving sealing between the sheath 40 and the vessel wall / opening. It’ s also contemplated that the vessel will recoil more than the sheath 40, also improving sealing between the sheath 40 and the vessel wall / opening.

[0113] Now with reference to FIG. 14, the dilator 550 is illustrated. The dilator 550 includes a dilator shaft 552 having an elongated body 568 with an expansion element 554 provided thereon. The dilator 550 further includes a second expansion element 555, configured to expand the proximal portion 44 and / or strain relief portion 46 of the sheath 40. As illustrated in FIG. 14, the second expansion element 555, is wider / has a larger diameter than the remainder of the elongated body 568 and the expansion element 554. As such, when the dilator 550 is advanced within the sheath 40, expansion element 554 will dilate the elongated body portion of the sheath 40 while the second expansion element 555 will dilate the proximal portion 44 and / or strain relief portion 46 of the sheath 40. In some examples, the dilator shaft has a diameter of 12 F (4 mm) and the second expansion element 555 has a diameter of 25 F (8.33 mm).

[0114] As illustrated in FIG. 14, the dilator 550 includes a tapered portion, which can be a step portion 567 between the elongated body 568 and the second expansion element 555. The step portion 567 tapers from the second expansion element 555 to the diameter of the elongated body 568. In some examples, the angle of the taper of the step portion 567 corresponds with the angle of the sheath 40 at the distal end of the strain relief layer 46 / proximal end portion. The second expansion element 555 further includes a length L in a range of 60 mm to 150 mm, corresponding to the length of the strain relief layer 46 / proximal end portion of the sheath 40.

[0115] In some examples, the second expansion element 555 further includes a shoulder 559 extending radially from the outer surface of the second expansion element 555, where the shoulder 559 is sized and configured to engage the sheath hub 24 to restrict axial movement of the dilator 550 within the sheath 40 beyond a predetermined distance within the sheath 40. For example, the shoulder 559 can be located along the second expansion element 555, such that the distal end of the second expansion element 555 does not extend beyond the distal end of the strain relief layer 46 and / or proximal end portion of the sheath 40, thereby preventing the second expansion element 555 from inadvertently expanding the elongated body portion of the sheath 40.

[0116] In some examples, the second expansion element 555 also includes a plurality of indica markings 563 corresponding to an insertion depth of the dilator 550 within the sheath 40. This allows the clinician to insert the dilator 550 to a depth according to subject-specific characteristics. For example, the clinician can dilate a length of the proximal portion 44 (or strain relief layer 46) of the sheath 40 corresponding to the distance between sheath hub 24 and the arteriotomy, thereby improving sealing between the vessel and the sheath.

[0117] Now with reference to FIG. 15, the dilator 650 is illustrated. The dilator 650 includes a dilator shaft 552 having an elongated body 668 defining the expansion element. The dilator 650 is configured to expand the proximal portion 44 and / or strain relief layer 46 of the sheath 40. In some examples, the dilator shaft has a diameter of 25 F (4 mm). Further, the dilator shaft includes a length L in a range of 150 mm.

[0118] As illustrated in FIG. 15, the dilator 650 includes a dilator hub 682 defining a shoulder 659 sized and configured to engage the sheath hub 24 to restrict axial movement of the dilator 650 beyond a predetermined distance within the sheath 40. Similar to the dilator 550, the length of the elongated body 668 extending distally from the shoulder 659 can correspond with the length of the length of the strain relief layer 46 and / or proximal end portion 44 of the sheath 40, such that the elongated body 668 does not inadvertently expand the elongated body portion of the sheath 40.

[0119] In some examples, the dilator shaft 652 also includes a plurality of indica markings 663 corresponding to an insertion depth of the dilator 650 within the sheath 40. This allows the clinician to insert the dilator 650 to a depth according to subject-specific characteristics. For example, the clinician can dilate a length of the sheath 40 (proximal portion 44 or strain relief layer 46) corresponding to the distance between sheath hub 24 and the arteriotomy, improving sealing between the vessel and the sheath.

[0120] A method of delivering / advancing a medical through a sheath is provided. An introducer sheath 40, 140, 240, 340 according to any example herein is provided.

[0121] The distal end of the introducer 100 is inserted into the proximal end 44 of the sheath 40, 140, 240, 340 and advanced into the central lumen 42 of the sheath 40, 140, 240, 340 as shown in FIGS. 2 and 13. The introducer 100 is advanced within the central lumen 42 of the sheath 40 in a distal direction toward the distal end 43 of the sheath 40, 140, 240, 340.

[0122] When used to deliver a medical device to a subject the sheath 40, 140, 240, 340 and introducer 100 are least partially inserted into the subject’s blood vessel and advanced to the treatment site. In some examples, the expandable sheath 40 is inserted into the femoral artery or other vessels of the subject’s body. The vasculature, such as the femoral artery, may benarrow or stiff, and may be difficult to easily insert a delivery apparatus therein. For example, the delivery apparatus may be larger than the vasculature, or may be unwieldy to penetrate through the skin or vasculature of the subject to pass therethrough by itself. Also, the vasculature may be too fragile to receive the delivery apparatus without the use of an introducer sheath 40, 140, 240, 340. The use of the combined sheath 40, 140, 240, 340 and introducer 100, allows for a smaller diameter sheath to be used, thereby reducing the push force needed to advance the sheath 40, 140, 240, 340 / introducer 100 into and through the subject’s blood vessel is reduced helping to minimize trauma to the vessel.

[0123] In some examples, a guidewire is optionally positioned at the treatment site and the sheath 40, 140, 240, 340 and introducer 100 are advanced over the guidewire.

[0124] Once the combined sheath 40, 140, 240, 340 and introducer 100 are positioned at the treatment site, the introducer 100 is then withdrawn in a proximal direction within the central lumen 42 of the sheath 40, 140, 240, 340. The introducer 100 is then fully withdrawn from the central lumen 42 of the sheath 40, 140, 240, 340, leaving the sheath 40 within the subject's vasculature.

[0125] In some examples, the dilator 550, 650 as described herein is then provided for expanding the central lumen 42 of the sheath 40 before passage of the medical device therethrough. For example, as described herein, passing the dilator 550, 650 into / through the central lumen 42 of the sheath 40, 140, 240, 340 pre -dilates or expands a portion of the sheath 40, 140, 240, 340 and / or blood vessel corresponding to the location of the expansion element 554, second expansion element 555 and / or elongated body 668. Providing this initial expansion reduces the push force necessary to advance the medical device and / or delivery system through the sheath 40, 140, 240, 340 and / or blood vessel.

[0126] The distal end 572, 672 of the dilator 550, 650 is advanced at least partially within the central lumen 42 of the sheath 40, 140, 240, 340. The elongated body 558, 668 of the dilator 550, 650 is sized and configured to be received (for example, slidably and or rotatably received) within the central lumen 42 of the sheath hub 24.

[0127] The sheath 40, 140, 240, 340 (including the proximal portion and / or strain relief portion) expands in response to an outwardly directed radial force exerted against the central lumen 42 of the sheath 40, 140, 240, 340 by expansion element 554, second expansion element 555, and / or elongated body 668. Because the outer diameter expansion element 554, second expansion element 555, and / or elongated body 668 is greater than the inner diameter of the sheath, movement of the expansion element 554, second expansion element 555, and / or elongated body 668 within the central lumen 42 of the sheath 40 causes the sheath 40,140, 240, 340 and / or the corresponding portion of the proximal portion / strain relief portion 46 to radially expand.

[0128] The dilator 550, 650 is further advanced a desired distance within the sheath 40, 140, 240, 340. As described herein the dilator 550, 650 can include indicia 563, 663 that the clinician can use to determine advance the dilator 550, 650 a desired length within the sheath 40, 140, 240, 340.

[0129] Once the desired length of the sheath 40, 140, 240, 340, proximal portion, and / or strain relief portion 46 is expanded, the dilator 550, 650 is withdrawn from the central lumen 42 of the sheath 40, 140, 240, 340. In some examples, the sheath 40, 140, 240, 340, proximal portion, and / or strain relief portion 46 are radially biased in an inward direction such that withdrawing the dilator 550, 650 from the sheath 40, 140, 240, 340 causes the corresponding portion of the sheath to at least partially (locally) contract back toward the unexpanded configuration.

[0130] While pre -dilating the sheath 40, 140, 240, 340 using the dilator 550, 650 is described as following positioning the sheath 40, 140, 240, 340 at the treatment site, in some examples, the dilator 550, 650 may be used to pre-dilate the sheath prior to inserting the sheath into the subject.

[0131] With the dilator 200 removed, the medical device is introduced into the proximal end of the central lumen 42 of the sheath 40, 140, 240, 340. Because the sheath 40, 140, 240, 340, proximal portion, and / or strain relief portion 46 have been pre-dilated / expanded, the push forces necessary to advance the medical device through the sheath are reduced compared to a non-dilated sheath. Additionally, because the sheath 40, 140, 240, 340 has been pre-dilated, the proximal portion and / or strain relief portion of the sheath maintains a larger diameter, thereby improving sealing between the sheath and the blood vessel.

[0132] With the central lumen 42 of the sheath 40, 140, 240, 340 clear, the medical device is then advanced into the central lumen 42 of the sheath 40, 140, 240, 340. Accessing the treatment site may require creating an opening in the heart tissue (for example, foramen ovalis) of the subject. In some examples, a cutting instrument can be advanced through the sheath 40, 140, 240, 340 to create an opening in the subject’s heart tissue.

[0133] The medical device, for example an implant, is advanced through the central lumen 42 of the sheath 40, 140, 240, 340 and beyond the distal opening to the treatment site within the blood vessel and / or heart tissue. In some examples, the sheath 40, 140, 240, 340 is sized and configured such that advancing the medical device through the sheath 40, 140, 240, 340 causes the sheath 40, 140, 240, 340 to locally expand from an unexpanded configuration at afirst diameter to an expanded configuration at a second, larger, diameter in response to an outwardly directed radial force exerted on the central lumen by the medical device, and then locally contract at least partially back to the unexpanded configuration as the medical device moves within the central lumen 42. With the distal end of the sheath 40, 140, 240, 340 positioned at the treatment site, the medical device is deployed beyond distal opening of the sheath 40, 140, 240, 340 and delivered to the subject.

[0134] In some examples, the medical device / implant is a prosthetic device 12 mounted in a radially crimped state on a delivery apparatus, and advancing the prosthetic device 12 through the central lumen 42 of the sheath 40, 140, 240, 340 includes advancing the delivery apparatus and the prosthetic device through central lumen 42 of the sheath 40, 140, 240, 340 and into a vasculature of the subject. 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 subject. In some examples, the prosthetic heart valve is mounted on a balloon catheter of the delivery apparatus as the prosthetic heart valve is advanced through the sheath 40, 140, 240, 340.

[0135] Exemplary Aspects

[0136] 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.

[0137] Example 1. A sheath system for deploying a medical device, the sheath system comprising: a braided layer, and a reinforced proximal end portion where the sheath is coupled to a sheath hub assembly, where a reinforcing element is coupled to the braided layer along the reinforced proximal end portion.

[0138] Example 2. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising: an elongated body having a distal end portion and a proximal end portion, the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid, the first and second set of filaments intersect at an intersection axis extending along a length of the elongated body, wherein the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and the intersection axis, wherein the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first orsecond set of filaments and the intersection axis, and wherein the first angle is greater than the second angle.

[0139] Example 3. The expandable sheath according to any example herein, particularly example 2, wherein the first angle is in a range from 20 degrees to 30 degrees, and wherein the second angle is in a range from 15 degrees to 20 degrees.

[0140] Example 4. The expandable sheath according to any example herein, particularly examples 2 and 3, wherein the first angle of the biaxial braid increases a radial strength of the proximal end portion compared to a radial strength of the distal end portion.

[0141] Example 5. The expandable sheath according to any example herein, particularly examples 2-4, wherein at the proximal end portion, the first set of filaments are oriented parallel to a first axis and the second set of filaments are oriented parallel to a second axis, at the distal end portion, the first set of filaments are oriented parallel to a third axis and the second set of filaments are oriented parallel to a fourth axis, the first angle is defined between the first or second axis and the intersection axis, and the second angle is defined between the third or fourth axis and the intersection axis.

[0142] Example 6. The expandable sheath according to any example herein, particularly examples 2-5, further comprising a helical wire coupled to the elongated body along proximal end portion.

[0143] Example 7. The expandable sheath of according to any example herein, particularly example 6, wherein the helical wire increases a radial strength of the proximal end portion, and wherein the helical wire defines a helical angle in a range from 89 degrees to 30 degrees.

[0144] Example 8. The expandable sheath according to any example herein, particularly examples 2-7, wherein the intersection between the first and second set of filaments defines a junction, and wherein the junction includes a junction locking material configured to restrict axial movement of the biaxial braid while allowing pivotable movement of the junction.

[0145] Example 9. The expandable sheath of according to any example herein, particularly example 8, wherein the junction locking material includes at least one of a mechanical coupler and a chemical coupler.

[0146] Example 10. A method of manufacturing the expandable sheath according to any example herein, particularly examples 8-9, comprising dipping the proximal end portion of the elongated body into a molten form of the junction locking material, and curing the junction locking material in the junction.

[0147] Example 11. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising: an elongated body having a distal end portion and a proximal end portion,the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid; and a helical wire coupled to the proximal end portion of the elongated body, the helical wire increases a radial strength of the proximal end portion.

[0148] Example 12. The expandable sheath according to any example herein, particularly example 11, wherein the helical wire defines a helical angle in a range from 89 degrees to 30 degrees.

[0149] Example 13. The expandable sheath according to any example herein, particularly examples 11-12, wherein the helical wire is located between the first and second set of filaments.

[0150] Example 14. The expandable sheath according to any example herein, particularly examples 11-13, wherein the helical wire is located radially inward or radially outward of the braided layer.

[0151] Example 15. The expandable sheath according to any example herein, particularly examples 11-14, wherein the first and second set of filaments intersect at an intersection axis extending along a length of the elongated body.

[0152] Example 16. The expandable sheath according to any example herein, particularly example 15, wherein the intersection between the first and second set of filaments defines a junction, and wherein the junction includes a junction locking material configured to restrict axial movement of the biaxial braid while allowing pivotable movement of the junction.

[0153] Example 17. The expandable sheath according to any example herein, particularly examples 15-16, wherein the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and the intersection axis, the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first or second set of filaments and the intersection axis, and the first angle is greater than the second angle.

[0154] Example 18. The expandable sheath according to any example herein, particularly example 17, wherein the first angle is in a range from 20 degrees to 30 degrees, and wherein the second angle is in a range from 15 degrees to 20 degrees.

[0155] Example 19. The expandable sheath according to any example herein, particularly examples 17-18, wherein the first angle of the biaxial braid increases a radial strength of the proximal end portion compared to a radial strength of the distal end portion.

[0156] Example 20. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising: an elongated body having a distal end portion and a proximal end portion,the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together, wherein an intersection between the first and second set of filaments defines a junction, and wherein, along the proximal end portion, the junction includes a junction locking material configured to restrict axial movement first and second set of filaments of the braided layer while allowing pivotable movement of the junction and radial expansion of the proximal end portion.

[0157] Example 21. The expandable sheath according to any example herein, particularly example 20, wherein the junction locking material includes at least one of a mechanical coupler and a chemical coupler.

[0158] Example 22. A method of manufacturing the expandable sheath according to any example herein, particularly examples 20-21, comprising dipping the proximal end portion of the elongated body into a molten form of the junction locking material, and curing the junction locking material in the junction.

[0159] Example 23. The expandable sheath according to any example herein, particularly examples 21-22, wherein the first set of filaments and a second set of filaments are braided together in a biaxial braid, the first and second sets of filaments intersect at an intersection axis extending along a length of the elongated body, the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and the intersection axis, wherein the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first or second set of filaments and the intersection axis, and wherein the first angle is greater than the second angle.

[0160] Example 24. The expandable sheath according to any example herein, particularly examples 21-23, further comprising a helical wire coupled to the proximal end portion, and wherein the helical wire increases a radial strength of the proximal end portion.

[0161] Example 25. The expandable sheath according to any example herein, particularly example 24, wherein the helical wire defines a helical angle in a range from 89 degrees to 30 degrees.

[0162] Example 26. A sheath system comprising: a radially expandable sheath defining a central lumen extending therethrough: and a dilator sized and configured to be received within the central lumen of the sheath, the dilator including: an elongated dilator shaft including an expansion element provided thereon, wherein the central lumen is movable 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, larger diameter, wherein the elongateddilator shaft includes a plurality of indica markings corresponding to insertion depth of the dilator within the sheath.

[0163] Example 27. The sheath system according to any example herein, particularly example 26, wherein the dilator includes: a first expansion element extending distally from a proximal end of the dilator shaft and including a tapered distal end, and a second expansion element located between a distal end of the dilator and the first expansion element, wherein movement of the second expansion element within the central lumen of the sheath causes the sheath to radially expand, wherein movement of the first expansion element within the central lumen of the sheath causes a proximal end portion of the sheath to radially expand.

[0164] Example 28. The sheath system according to any example herein, particularly example 27, wherein movement of the first expansion element within the central lumen of the sheath causes the proximal end portion of the sheath to plastically deform.

[0165] Example 29. The sheath system according to any example herein, particularly examples 27-28, wherein the proximal end portion of the sheath includes a strain relief portion having an increased resistance to radial expansion compared to a distal end portion of the sheath.

[0166] Example 30. The sheath system according to any example herein, particularly examples 26-29, wherein the elongated dilator shaft has a length of 150 millimeters.

[0167] Example 31. A method of delivering a medical device through a sheath, the method comprising: providing an expandable sheath including a braided layer, the expandable sheath according to any one of examples 1-30; introducing a medical device into a proximal end of a central lumen of the expandable sheath; advancing a medical device through the central lumen of the expandable sheath causing the sheath to locally expand from an unexpanded configuration toward expanded configuration at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the central lumen; and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen.

[0168] Example 32. The method of according to any example herein, particularly example 31, wherein the expandable sheath includes: an elongated body having a distal end portion and a proximal end portion, the elongated body including the braided layer, the braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid, the first and second set of filaments intersect at an intersection axis extending along a length of the elongated body, wherein the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and theintersection axis, wherein the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first or second set of filaments and the intersection axis, and wherein the first angle is greater than the second angle.

[0169] Example 33. The method according to any example herein, particularly examples 31- 32, wherein the expandable sheath further includes: an elongated body having a distal end portion and a proximal end portion, the elongated body including the braided layer; and a helical wire coupled to the elongated body along proximal end portion.

[0170] Example 34. The method according to any example herein, particularly examples 32- 33, wherein the intersection between the first and second set of filaments defines a junction, and wherein the junction includes a junction locking material configured to restrict axial movement of the biaxial braid while allowing pivotable movement of the junction.

[0171] Example 35. A method of delivering a medical device through a sheath, the method comprising: providing an expandable sheath including a braided layer, the expandable sheath according to any one of examples 1-30; introducing the dilator into a proximal end of a central lumen of the sheath; advancing the dilator through a proximal portion of the sheath such that the expansion element provided on the dilator exerts an outwardly directed radial force against the central lumen and causing the proximal portion of the sheath proximate the expansion element to locally expand from an unexpanded configuration toward an expanded configuration; locally contracting the proximal portion of the sheath towards the unexpanded configuration as the expansion element passes through a corresponding portion of the central lumen of sheath; removing the dilator from the central lumen of the sheath; introducing a medical device into the proximal end of the central lumen of the expandable sheath; advancing a medical device through the central lumen of the expandable sheath causing the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the central lumen; and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen.

[0172] Example 36. The method of according to any example herein, particularly example 35, wherein the proximal portion of the sheath corresponds with a strain relief portion of the sheath.

[0173] Example 37. The method according to any example herein, particularly examples 35- 36, wherein the expandable sheath includes: an elongated body having a distal end portion and a proximal end portion, the elongated body including the braided layer, the braided layercomprising a first set of filaments and a second set of filaments braided together in a biaxial braid, the first and second set of filaments intersect at an intersection axis extending along a length of the elongated body, wherein the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and the intersection axis, wherein the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first or second set of filaments and the intersection axis, and wherein the first angle is greater than the second angle.

[0174] Example 38. The method according to any example herein, particularly examples 35- 37, wherein the expandable sheath further includes: an elongated body having a distal end portion and a proximal end portion, the elongated body including the braided layer; and a helical wire coupled to the elongated body along proximal end portion.

[0175] Example 39. The method according to any example herein, particularly examples 35- 38, wherein the intersection between the first and second set of filaments defines a junction, and wherein the junction includes a junction locking material configured to restrict axial movement of the biaxial braid while allowing pivotable movement of the junction.

[0176] Example 40. A method of inserting a medical device into a blood vessel of a subject, the method comprising: inserting a radially expandable sheath according to any one of examples 1-30 at least partially into the blood vessel of a subject; introducing a medical device into a proximal end of a central lumen of the sheath; advancing the medical device through the sheath; and advancing the medical device beyond a distal opening in the sheath to a treatment site within the blood vessel.

[0177] Example 41. The method of according to any example herein, particularly example 40, further including: after inserting the sheath into the blood vessel of the subject, removing an introducer from the central lumen of the sheath; introducing a dilator into the central lumen of the sheath, the dilator including: a dilator shaft having a proximal end and an opposing distal end; a first dilating portion adjacent the proximal end of the dilator shaft; and advancing the dilator shaft through a portion of the central lumen of the sheath such that the first dilating portion exerts an outwardly directed radial force against the central lumen and causes the sheath proximate the first dilating portion to locally expand from an unexpanded configuration toward an expanded configuration; and removing the dilator from the sheath.

[0178] Example 42. The method according to any example herein, particularly examples 40- 41, wherein the dilator further includes a second dilating portion located between the distal end of the dilator shaft and the first dilating portion, where an elongated body portion of the dilator shaft extends between the first dilating portion and second dilating portion, wherein adiameter of the first dilating portion and a diameter of the second dilating portion is greater than a diameter of the elongated body portion, and the diameter of the first dilating portion is greater than the diameter of the second dilating portion; advancing the dilator shaft through a portion of the central lumen of the sheath such that at least one of the first dilating portion or the second dilating portion exerts an outwardly directed radial force against the central lumen and causes the sheath proximate the first dilating portion or the second dilating portion to locally expand from the unexpanded configuration to the expanded configuration; and removing the dilator from the sheath.

[0179] Example 43. The method according to any example herein, particularly examples 40- 42, further including: inserting a guide wire at least partially into the blood vessel of a subject; advancing the sheath over the guide wire through the blood vessel to the treatment site; and advancing the dilator over the guide wire through the sheath to the treatment site.

[0180] Example 44. The method according to any example herein, particularly examples 40- 43, wherein the medical device is a prosthetic device mounted in a radially crimped state on a delivery apparatus, wherein advancing the prosthetic device through the central lumen of the sheath comprises advancing the delivery apparatus and the prosthetic device through lumen of the sheath and into a vasculature of the subject.

[0181] Example 45. The method according to any example herein, particularly example 44, wherein the prosthetic device comprises a prosthetic heart valve and the method further comprises implanting the prosthetic heart valve at a treatment site within the subject.

[0182] Example 46. The method according to any example herein, particularly example 44, wherein the prosthetic heart valve is mounted on a balloon catheter of the delivery apparatus as the prosthetic heart valve is advanced through the sheath.

[0183] Example 47. The method according to any example herein, particularly examples 40-46, wherein the sheath is inserted into a femoral artery of the subject.

[0184] Example 48. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising: an elongated body having a distal end portion and a proximal end portion; and a helical wire coupled to the proximal end portion of the elongated body, the helical wire configured to increase a radial strength of the proximal end portion.

[0185] Example 49. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising: an elongated body having a distal end portion and a proximal end portion, the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together; wherein the braid at the proximal end portion of the elongated body has a first angle defined between the first and second set of filaments,wherein the braid at a second portion distal to the proximal end portion has a second angle defined between the first and second set of filaments, and wherein the first angle is different than the second angle.

[0186] Example 50. The sheath of example 48 or 49, further comprising any feature of any of examples 1-30.

[0187] 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.

[0188] Reference throughout this specification to “an implementation’’ means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least one implementation. Thus, appearances of the phrases “in an implementation” or “in some implementations” in various places throughout this specification are not necessarily all referring to the same implementation or a single exclusive implementation. Furthermore, the particular features, structures, or characteristics described herein may be combined in any suitable manner in one or more implementations.

[0189] Groupings of alternative elements or implementations of the disclosure herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0190] Combinations, described herein, such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof’ include any combination of A, B, and / or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof’ may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, and any such combination may contain one or more members of its constituents A, B, and / or C. For example, a combination of A and B may comprise one A and multiple B's, multiple A's and one B, or multiple A's and multiple B's.

Claims

CLAIMSWhat is claimed is:

1. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising:an elongated body having a distal end portion and a proximal end portion, the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid, the first and second set of filaments intersect at an intersection axis extending along a length of the elongated body,wherein the biaxial braid at the proximal end portion of the elongated body has a first angle defined between the first or second set of filaments and the intersection axis, wherein the biaxial braid at the distal end portion of the elongated body has a second angle defined between the first or second set of filaments and the intersection axis, and wherein the first angle is greater than the second angle.

2. The expandable sheath of claim 1, wherein the first angle is in a range from 20 degrees to 30 degrees, and wherein the second angle is in a range from 15 degrees to 20 degrees.

3. The expandable sheath of any of claims 1 and 2, wherein the first angle of the biaxial braid increases a radial strength of the proximal end portion compared to a radial strength of the distal end portion.

4. The expandable sheath of any of claims 1-3, whereinat the proximal end portion, the first set of filaments are oriented parallel to a first axis and the second set of filaments are oriented parallel to a second axis,at the distal end portion, the first set of filaments are oriented parallel to a third axis and the second set of filaments are oriented parallel to a fourth axis,the first angle is defined between the first or second axis and the intersection axis, and the second angle is defined between the third or fourth axis and the intersection axis.

5. The expandable sheath of any of claims 1-4, further comprising a helical wire coupled to the elongated body along proximal end portion.

6. The expandable sheath of claim 5, wherein the helical wire increases a radial strength of the proximal end portion, and wherein the helical wire defines a helical angle in a range from 89 degrees to 30 degrees.

7. The expandable sheath of any of claims 1-6, wherein the intersection between the first and second set of filaments defines a junction, and wherein the junction includes a junction locking material configured to restrict axial movement of the biaxial braid while allowing pivotable movement of the junction.

8. The expandable sheath of claim 7, wherein the junction locking material includes at least one of a mechanical coupler and a chemical coupler.

9. A method of manufacturing the expandable sheath of any of claims 7-8, comprising dipping the proximal end portion of the elongated body into a molten form of the junction locking material, andcuring the junction locking material in the junction.

10. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising:an elongated body having a distal end portion and a proximal end portion, the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together in a biaxial braid; anda helical wire coupled to the proximal end portion of the elongated body, the helical wire increases a radial strength of the proximal end portion.

11. The expandable sheath of claim 10, wherein the helical wire increases a radial strength of the proximal end portion, and wherein the helical wire defines a helical angle in a range from 89 degrees to 30 degrees.

12. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising:an elongated body having a distal end portion and a proximal end portion, the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together,wherein an intersection between the first and second set of filaments defines a junction, andwherein, along the proximal end portion, the junction includes a junction locking material configured to restrict axial movement first and second set of filaments of the braided layer while allowing pivotable movement of the junction and radial expansion of the proximal end portion.

13. The expandable sheath of claim 12, wherein the junction locking material includes at least one of a mechanical coupler and a chemical coupler.

14. A method of delivering a medical device through a sheath, the method comprising:providing an expandable sheath including a braided layer, the expandable sheath according to any one of claims 1-13;introducing a medical device into a proximal end of a central lumen of the expandable sheath;advancing a medical device through the central lumen of the expandable sheath causing the sheath to locally expand from an unexpanded configuration toward expanded configuration at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the central lumen; andlocally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen.

15. A sheath system comprising:a radially expandable sheath defining a central lumen extending therethrough; and a dilator sized and configured to be received within the central lumen of the sheath, the dilator including:an elongated dilator shaft including an expansion element provided thereon, wherein the central lumen is movable 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, larger diameter,wherein the elongated dilator shaft includes a plurality of indica markings corresponding to insertion depth of the dilator within the sheath.

16. The sheath system of claim 15, wherein the dilator includes:a first expansion element extending distally from a proximal end of the dilator shaft and including a tapered distal end, anda second expansion element located between a distal end of the dilator and the first expansion element,wherein movement of the second expansion element within the central lumen of the sheath causes the sheath to radially expand,wherein movement of the first expansion element within the central lumen of the sheath causes a proximal end portion of the sheath to radially expand.

17. The sheath system of claim 16, wherein movement of the first expansion element within the central lumen of the sheath causes the proximal end portion of the sheath to plastically deform.

18. The sheath system of any of claims 15-17, wherein the proximal end of the sheath includes a strain relief portion having an increased resistance to radial expansion compared to a distal end portion of the sheath.

19. The sheath system of any of claims 15-18, wherein the elongated dilator shaft has a length of 150 millimeters.

20. A method of delivering a medical device through a sheath, the method comprising:providing an expandable sheath including a braided layer, the expandable sheath according to any one of claims 1-13;introducing a dilator according to any one of claims 14-18 into a proximal end of a central lumen of the sheath;advancing the dilator through a proximal portion of the sheath such that an expansion element provided on the dilator exerts an outwardly directed radial force against the central lumen and causing the proximal portion of the sheath proximate the expansion element to locally expand from an unexpanded configuration toward an expanded configuration;locally contracting the proximal portion of the sheath towards the unexpanded configuration as the expansion element passes through a corresponding portion of the central lumen of sheath;removing the dilator from the central lumen of the sheath;introducing a medical device into the proximal end of the central lumen of the expandable sheath;advancing a medical device through the central lumen of the expandable sheath causing the sheath to locally expand from the unexpanded configuration to the expanded configuration at a location proximate the medical device in response to the outwardly directed radial force of the medical device exerted against the central lumen; and locally contracting the sheath at least partially back to the unexpanded configuration as the medical device passes through the central lumen.

21. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising;an elongated body having a distal end portion and a proximal end portion; and a helical wire coupled to the proximal end portion of the elongated body, the helical wire configured to increase a radial strength of the proximal end portion.

22. An expandable sheath for delivering a prosthetic valve, the expandable sheath comprising;an elongated body having a distal end portion and a proximal end portion, the elongated body including a braided layer comprising a first set of filaments and a second set of filaments braided together;wherein the braid at the proximal end portion of the elongated body has a first angle defined between the first and second set of filaments,wherein the braid at a second portion distal to the proximal end portion has a second angle defined between the first and second set of filaments, andwherein the first angle is different than the second angle.

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