Introducer sheath and loader

Abstract

Disclosed herein are introducer sheaths and loaders (300). The loader (300) aids in advancement of a delivery device into the sheath and is both flushable and includes a removable loader tube (312).

Description

INTRODUCER SHEATH AND LOADERCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 691,222, filed September 4, 2024, which is incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The present application is directed to a sheath and introducer / dilator for use with catheter-based technologies for repairing and / or replacing heart valves, as well as for delivering 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 reach target destinations rather than surgically opening target site. There are many types of diseases states that can be treated via interventional methods including coronary blockages, valve replacements (TAVR) and brain aneurysms. These techniques involve using wires, catheters, balloons, electrodes and other thin devices to travel down the length of the blood vessels from the access site to the target site. The devices have a proximal end which the clinician controls outside of the body and a distal end inside the body which is responsible for treating the disease state. Percutaneous interventional procedures offer several advantages over open surgical techniques. First, they require smaller incision sites which reduces scarring and bleeding as well as infection risk. Procedures are also less traumatic to the tissue, so recovery times are reduced. Finally, interventional techniques can usually be performed much faster, and with fewer clinicians participating in the procedure, so overall costs are lowered. In some cases, the need for anesthesia is also eliminated, further speeding up the recovery process and reducing risk.

[0005] A single procedure typically uses several different guidewires, catheters, and balloons to achieve the desired effect. One at a time, each tool is inserted and then removed from the access site sequentially. For example, a guidewire is used to track the correct location within the body. Next a balloon may be used to dilate a section of narrowed blood vessel. Last, animplant 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 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.

[0007] Loaders are used to aid insertion of the delivery apparatus into the sheath.SUMMARY

[0008] Aspects of loaders described below can provide a flushable system that also includes a removable or peelable loader tube. The loader includes a proximal seal that is sized to sealingly engage a delivery device and a distal seal that that allows fluid flow around the delivery device. A flush cavity is formed between the proximal seal and the loader seal and a flush port allows a clinician to inject fluid therethrough into the loader. The loader tube includes a severance feature that allows removal of the loader tube from the loader after advancement of the delivery device into a sheath. A hub supports the loader tube during use and is removable from the loader after advancement of the delivery device. Removal of the loader tub and hub provides a small space claim for the loader after advancement and during use of the delivery device. The loaders discussed herein provide a flushable, peelable loader that promotes ease of use of the delivery device after advancement into the sheath.

[0009] Aspects of the present expandable sheath system can minimize trauma to the vessel and damage to the sheath and prosthetic device by reducing push forces through the blood vessel and / or sheath by providing a combined introducer-dilator that can be used to dilate the blood vessel and or sheath before the delivery device / implant is introduced. Some examplescan comprise a sheath with a smaller profile than that of prior art introducer sheaths. Furthermore, certain examples can reduce the length of time a procedure takes, as well as reduce the risk of a longitudinal or radial vessel tear, or plaque dislodgement because lower push force is required and only one sheath is used, rather than several different sizes of sheaths and / or dilators. Furthermore, some examples facilitate retrieval of devices that may become damaged during use.

[0010] In one of its basic configurations, the present disclosure provides a sheath system for deploying a medical device including a loader that is both flushable and includes a removable loader tube. 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 aspects, the techniques described herein relate to a loader system including a cap including a flush aperture. In some aspects, the loader system also includes an proximal loader seal engaged with the cap and defining an proximal seal aperture configured to receive a delivery system. In some aspects, the loader system also includes a distal loader seal engaged with the cap and defining a distal seal aperture configured to receive the delivery system. In some aspects, the cap, the proximal loader seal, and the distal loader seal define a flush cavity in fluid communication with the flush aperture. In some aspects, the loader system also includes a hub rotatably engaged with the cap and defining a cutout. The loader system also includes a loader tube engaged with the distal loader seal. In some aspects, the loader tube is supported by the hub and includes a severance feature configured to aid removal of the loader tube from the loader system.

[0012] In some aspects, the techniques described herein relate to an introducer and loader system including: an introducer including: an introducer housing; an introducer sheath extending from the introducer housing; and an introducer seal assembly positioned within the introducer housing and providing selective access to the introducer sheath via the introducer housing. In some aspects, the introducer and loader system further includes a loader including: a cap defining a proximal seal seat and a distal seal seat, the cap including a flush aperture positioned between the proximal seal seat and the distal seal seat; a proximal loader seal engaged with the proximal seal seat and defining a proximal seal aperture; a distal loader seal engaged with the distal seal seat and defining a distal seal aperture larger than theproximal seal aperture; and a loader tube engaged with the distal loader seal. In some aspects, the loader tube is sized to be received within the introducer sheath and including a severance feature configured to aid removal of the loader tube from the loader.

[0013] In some aspects, the techniques described herein relate to a minimally-invasive prosthetic heart valve delivery system, including: an introducer sheath having a lumen therethrough of no greater than 24 French. In some aspects, the system further includes a balloon catheter having a balloon on a distal end, the balloon catheter further including a steering mechanism for deflecting the distal end. In some aspects, the system further includes a balloon-expandable prosthetic heart valve crimped over the balloon, wherein an outer dimension of the balloon catheter having the prosthetic heart valve thereon is small enough to pass through the introducer sheath lumen. In some aspects, the steering mechanism includes a deflecting segment on the balloon catheter located just proximal to the balloon; and a loader between the introducer sheath and the balloon catheter providing an effective fluid seal against egress of blood through the introducer sheath in an absence or a presence of different sized medical implements. In some aspects, the loader includes: a cap including a flush aperture; a proximal loader seal engaged with the cap and defining an proximal seal aperture configured to receive a delivery system; a distal loader seal engaged with the cap and defining a distal seal aperture configured to receive the delivery system. In some aspects, the cap, the proximal loader seal, and the distal loader seal define a flush cavity in fluid communication with the flush aperture; a hub rotatably engaged with the cap and defining a cutout. In some aspects, a loader tube is engaged with the distal loader seal and sized to be received within the introducer sheath. In some aspects, the loader tube is supported by the hub and including a severance feature configured to aid removal of the loader tube from the loader.

[0014] In some aspects, the techniques described herein relate to a method for loading a prosthetic heart valve within a delivery apparatus, including: positioning a distal end of an introducer sheath in a femoral artery, a proximal end of the introducer sheath connected to a handle of the introducer sheath; securing the prosthetic heart valve to a retaining mechanism of the delivery apparatus, wherein the prosthetic heart valve includes an expandable frame member and a plurality of leaflets; pushing the prosthetic heart valve through an upstream loader seal of a loader, through a flush cavity of the loader, through a downstream loader seal of the loader, and into a loader tube of the loader to radially compress the prosthetic heart valve; flushing the flush cavity via a flush port formed in the loader between the upstream loader seal and the downstream loader seal; inserting the loader tube into the introducersheath; progressing the retaining mechanism of the delivery apparatus distally into the introducer sheath within the femoral artery; and removing the loader tube via a severance feature of the loader tube.

[0015] Various aspects of the examples described above can be combined based on desired sheath system characteristics.BRIEF DESCRIPTION OF DRAWINGS

[0016] The device is explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The drawings are not necessarily drawn to scale.

[0017] FIG. 1 is an elevation view of an expandable sheath along with an endovascular delivery apparatus for implanting a prosthetic implant.

[0018] FIG. 2 is an elevation view of an expandable sheath including an introducer locking hub, a sheath locking sleeve, and an introducer.

[0019] FIG. 3 is an elevation view of the expandable sheath of FIG. 2 along with an endovascular delivery apparatus for implanting a prosthetic implant.

[0020] FIG. 4 is an elevation view of an expandable sheath a sheath hub, an introducer locking hub, and a sheath locking sleeve of FIG. 2.

[0021] FIG. 5A is a cross-sectional view of the sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2.

[0022] FIG 5B is a cross-sectional view of the introducer cap, the sheath hub, the introducer locking hub, the sheath locking sleeve of FIG. 2.

[0023] FIG. 6 is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2.

[0024] FIG. 7 is a distal end view of the sheath locking sleeve of FIG. 2 and the proximal fluid seal of FIGS 5A-B.

[0025] FIG. 8A is a first elevation view of the introducer locking hub of FIG. 2 coupled to an introducer.

[0026] FIG. 8B is a second (rotated) elevation view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0027] FIG. 8C is a distal end view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0028] FIG. 8D is a partial side view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0029] FIG. 8E is a partial perspective view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0030] FIG. 8F is a partial perspective view of the introducer locking hub of FIG. 2 coupled to the introducer.

[0031] FIG. 9A is a distal end view of the introducer locking hub of FIG. 2.

[0032] FIG. 9B is a first elevation view of the introducer locking hub of FIG. 2.

[0033] FIG. 9C is a proximal end view of the introducer locking hub of FIG. 2.

[0034] FIG. 9D is a first perspective view of the introducer locking huh of FIG. 2.

[0035] FIG. 9E is a second elevation view of the introducer locking hub of FIG. 2.

[0036] FIG. 9F is a second perspective view of the introducer locking hub of FIG. 2.

[0037] FIG. 10A is a distal end view of the sheath locking sleeve of FIG. 2.

[0038] FIG. 10B is a first elevation view of the sheath locking sleeve of FIG. 2.

[0039] FIG. 10C is a proximal end view of the sheath locking sleeve of FIG. 2.

[0040] FIG. 10D is a first perspective view of the sheath locking sleeve of FIG. 2.

[0041] FIG. 10E is a second elevation view of the sheath locking sleeve of FIG. 2.

[0042] FIG. 10F is a second perspective view of the sheath locking sleeve of FIG. 2.

[0043] FIG. 11 is a side elevation cross-sectional view of a portion of the expandable sheath of FIGS. 1 and 2.

[0044] FIG. 12 is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2.

[0045] FIG. 13A is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2 with the outer layer removed for purposes of illustration.

[0046] FIG. 13B is a magnified view of a portion of the braided layer of the sheath of FIGS.1 and 2.

[0047] FIG. 14 is a magnified view of a portion of the expandable sheath of FIGS. 1 and 2 illustrating expansion of the sheath as a prosthetic device is advanced through the sheath.

[0048] FIG. 15 is a side view of the expandable sheath of FIGS. 1 and 2.

[0049] FIG. 16 is a magnified cross-sectional of the sheath of FIG. 15 along section line 16-16.

[0050] FIG. 17 is cross-sectional view of the unexpanded sheath of FIG. 16 along section line 17-17.

[0051] FIG. 18 is cross-sectional view of the unexpanded sheath of FIG. 15 along section line 18-18.

[0052] FIG. 19 is cross-sectional view of the unexpanded sheath of FIG. 15 along section line 19-19.

[0053] FIG. 20 is cross-sectional view of the expanded sheath of FIG. 15 along section line 19-19.

[0054] FIG. 21 is a side view of the expandable sheath of FIGS. 1 and 2.

[0055] FIG. 22 is a cross-sectional view of the unexpanded sheath of FIG. 21 along section line 22-22.

[0056] FIG. 23 is a cross-sectional view of the expanded sheath of FIG. 21 along section line 22-22.

[0057] FIG. 24 is a perspective view of a loader, according to some aspects.

[0058] FIG. 25 is a cross-sectional view of the loader of FIG. 24, according to some aspects.

[0059] FIG. 26 is an exploded view of the loader of FIG. 24, according to some aspects.

[0060] FIG. 27 is a top view of a loader tube of the loader of FIG. 24, according to some aspects.

[0061] FIG. 28 is a perspective view of a hub of the loader of FIG. 24, according to some aspects.

[0062] FIG. 29 is a perspective view of a distal retention ring of the loader of FIG. 24, according to some aspects.

[0063] FIG. 30 is another perspective view of the distal retention ring of FIG. 29.

[0064] FIG. 31 is a perspective view of distal loader seal of the loader of FIG. 24, according to some aspects.

[0065] FIG. 32 is another perspective view of the distal loader seal of FIG. 31.

[0066] FIG. 33 is a front view of the distal loader seal of FIG. 31.

[0067] FIG. 34 is a perspective view of a loader cap of the loader of FIG. 24, according to some aspects.

[0068] FIG. 35 is another perspective view of the loader cap of FIG. 24.

[0069] FIG. 36 is a cross-sectional view of the loader cap of FIG. 24.

[0070] FIG. 37 is a perspective view of a proximal loader seal of the loader of FIG. 24, according to some aspects.

[0071] FIG. 38 is another perspective view of the proximal loader seal of FIG. 37.

[0072] FIG. 39 is a perspective view of a proximal retention ring of the loader of FIG. 24, according to some aspects.

[0073] FIG. 40 is another perspective view of the proximal retention ring of FIG. 39.

[0074] FIG. 41 is a perspective view of a flush port of the loader of FIG. 24, according to some aspects.

[0075] FIG. 42 is a cross-sectional view of the loader of FIG. 24 loaded with the delivery apparatus of FIG. 1, according to some aspects.

[0076] FIG. 43 is a cross-sectional view of the loader of FIG. 24 with the loader tube and hub removed, according to some aspects.

[0077] FIG. 44 is a cross-sectional view of the loader of FIG. 24 with the loader tube and hub removed, according to some aspects.

[0078] In the drawings, like reference numbers and designations in the various drawings indicate like elements.DETAILED DESCRIPTION

[0079] 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, aspects, 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.

[0080] For purposes of this description, certain aspects, advantages, and novel features of the aspects of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed examples, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.

[0081] Features, integers, characteristics, compounds, chemical moieties, or groups described in conjunction with a particular aspect or example of the present disclosure are to be understood to be applicable to any other aspect or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The present disclosure is not restricted to the details of any foregoing examples. The present disclosure extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0082] It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0083] 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.

[0084] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0085] The terms “proximal” and “distal” as used herein refer to regions of a sheath, catheter, or delivery assembly. “Proximal” means that region closest to handle of the device, while “distal” means that region farthest away from the handle of the device.

[0086] “Axially” or “axial” as used herein refers to a direction along the longitudinal axis of the sheath.

[0087] 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.

[0088] Disclosed examples of an expandable sheath can minimize trauma to the vessel by allowing for temporary expansion of a portion of the introducer sheath to accommodate the delivery apparatus, followed by a return to the original diameter once the device passesthrough. Disclosed examples of the introducer sheath prevent the introducer / dilator from separating from the sheath during insertion by locking of the proximal hub of the introducer / dilator to the proximal hub of the sheath. Fixing the introducer / dilator and the sheath prevents the introducer / dilator from moving backward during insertion, thereby maintaining a snug fit and smooth transition between the introducer / dilator and the distal end of the sheath. Furthermore, present examples can reduce the length of time a procedure takes, as well as reduce the risk of a longitudinal or radial vessel tear, or plaque dislodgement because only one sheath is required, rather than several different sizes of sheaths. Examples of the present expandable sheath can avoid the need for multiple insertions for the dilation of the vessel.

[0089] Disclosed herein are elongate introducer sheaths that are particularly suitable for delivery of implants in the form of implantable heart valves, such as balloon-expandable implantable heart valves. Balloon-expandable implantable heart valves are well-known and will not be described in detail here. An example of such an implantable heart valve is described in U.S. Patent No. 5,411,552, and also in U.S. Patent No. 9,393,110, both of which are hereby incorporated by reference. The expandable introducer sheaths disclosed herein may also be used to deliver other types of implantable medical device, such as selfexpanding and mechanically expanding implantable heart valves, stents or filters. Beyond transcatheter heart valves, the introducer sheath system can be useful for other types of minimally invasive surgery, such as any surgery requiring introduction of an apparatus into a subject’s vessel. For example, the introducer sheath system can be used to introduce other types of delivery apparatus for placing various types of intraluminal devices (for example, stents, stented grafts, balloon catheters for angioplasty procedures, etc.) into many types of vascular and non-vascular body lumens (for example, veins, arteries, esophagus, ducts of the biliary tree, intestine, urethra, fallopian tube, other endocrine or exocrine ducts, etc.). The term “implantable” as used herein is broadly defined to mean anything - prosthetic or not - that is delivered to a site within a body. A diagnostic device, for example, may be an implantable.

[0090] Example expandable introducer sheaths are disclosed, for example, in U.S. Patent No. 8,690,936, entitled “Expandable Sheath for Introducing an Endovascular Delivery Device into a Body,” U.S. Patent No. 8,790,387, entitled “Expandable Sheath for Introducing an Endovascular Delivery Device into a Body,” U.S. Patent No. 10,639,152, entitled “Expandable Sheath and Methods of Using the Same,” U.S. Patent No. 10,792,471, entitled “Expandable Sheath,” U.S. Patent No. Application No. 16 / 407,057, entitled“Expandable Sheath with Elastomeric Cross Sectional Portions,” U.S. Patent No. 10,327,896, entitled “Expandable Sheath with Elastomeric Cross Sectional Portions,” U.S. Patent No. 11,273,062, entitled “Expandable Sheath,” Application No. PCT / US2021 / 019514, entitled “Expandable sheath for introducing an endovascular delivery device in to a body,” Application No. PCT / US2021 / 031227, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” Application No.PCT / US 2021 / 031275, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” U.S. Application No. 17 / 1 13,268, entitled “Expandable Sheath and Method of Using the Same,” Application No. PCT / US2021 / 058247, entitled “SelfExpanding, 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 / US 2022 / 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.

[0091] FIG. 1 illustrates an exemplary sheath 8 in use with a representative delivery apparatus 10, for delivering an implant 12, or other type of implantable (for example, tissue heart valve), to a patient. The delivery apparatus 10 can include a steerable guide catheter 14 (also referred to as a flex catheter) and a balloon catheter 16 extending through the guide catheter 14, and a nose catheter 15 extending through the balloon catheter 16. The guide catheter 14, balloon catheter 16, and nose catheter 15 in the illustrated example are adapted to slide longitudinally relative to each other to facilitate delivery and positioning of the implant 12 at an implantation site in a patient’s body as described in detail herein. It is contemplated that the sheath 8 can be used with any type of elongated delivery apparatus used for implanting balloon-expandable prosthetic valves, self-expanding prosthetic valves, and other prosthetic devices.

[0092] As described in more detail herein, in general, the sheath 8 comprises an elongate expandable tube that, in use, is inserted into a vessel (for example, transfemoral vessel,femoral artery, iliac artery) by passing through the skin of patient, such that the distal end of the sheath 8 is inserted into the vessel. Sheath 8 includes a hemostasis valve and / or sealing features at the proximal end of the sheath, for example, in the sheath hub 20, that provide hemostasis and prevents blood leakage from the patient through the sheath 8. The sheath 8, including an introducer 6, is advanced into the patient’s vasculature. Once positioned the introducer 6 is removed and the delivery apparatus 10 is inserted into / through the sheath 8, and the prosthetic device (implant 12) then be delivered and implanted within patient.

[0093] FIGS. 2 and 3, the introducer device / sheath assembly includes a sheath hub 20 at a proximal end of the device and an expandable sheath 8 extending distally from the sheath hub 20. The sheath 8 is coupled to the sheath hub 20 which in turn is removably coupled to a sheath locking system 18. The sheath locking system 18 allows the introducer 6, or other device desired to be removably couped (axially and rotatably) to the sheath 8.

[0094] As illustrated in FIGS. 2-6, the sheath hub 20 can function as a handle for the device. Sheath hub 20 also provides a housing for necessary seal assemblies and an access point for a secondary lumen (for example, fluid lumen) in fluid communication with the central lumen of the sheath hub 20. The seal assembly 24, as described herein and as shown in FIGS. 5A and 5B, is included in the sheath hub 20. The seal assembly 24 includes a proximal seal 24a, an intermediate seal 24b, and a distal seal 24c. When assembled, the introducer 6 passes through the seal assembly and extends distal of the sheath 8. The proximal seal 24a, the intermediate seal 24b, and the distal seal 24c are each formed to prevent unwanted fluid from advancing in the proximal direction through the sheath hub 20 and proximal of the seal assembly 24. They are each openable and closable to provide pressure variation to affect the desired fluid flow from a physician or technician.

[0095] The distal end of the sheath hub 20 includes threads 21 for coupling to a threaded sheath hub cap 22. The sheath 8 is provided between the sheath hub 20 and the sheath hub cap 22 such that coupling the sheath hub cap 22 to the sheath hub 20 fixes the sheath 8 to the sheath hub 20. The sheath hub cap 22 is a cylindrical cap having a cap body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal end and the distal end. The sheath hub cap 22 has a larger diameter at its proximal end than at its distal end.

[0096] The sheath hub 20 further has receiving slots 48 for coupling the sheath locking system 18, particularly the locking sleeve 28, to the sheath hub 20. The receiving slots 48 are openings which extend around a portion of the diameter of the sheath hub 20 and are sized and configured to accept the interference diameters 66 of the locking sleeve 28. Couplingbetween the receiving slots 48 and the interference diameters 66 axially and rotationally fixes the locking sleeve 28 and the sheath hub 20 relative to each other.

[0097] FIG. 2 illustrates the sheath 8 of FIG. 1 including a sheath locking system 18 which prevents axial and rotational translation of the introducer 6 with respect to the sheath 8. Example locking systems are disclosed in PCT / US2021 / 050006, entitled “Expandable Sheath Including Reverse Bayonet Locking Hub,” the disclosure of which is incorporated herein by reference. It is contemplated that the locking system disclosed herein can also be used to couple the sheath 8 / sheath hub 20 with other delivery apparatus components, catheters, dilators, etc. including the same mating features.

[0098] The sheath locking system 18 keeps the introducer 6 fixed with respect to the sheath 8 during insertion without requiring a physician or technician to hold the introducer 6 and the sheath 8 in place at the distal end. As illustrated in FIGS. 8A-8B, the sheath locking system 18 includes a locking sleeve 28 and an introducer locking hub 30 (including corresponding introducer 6). The locking sleeve 28 is coupled to the sheath 8 via the sheath hub 20. The locking sleeve 28 engages the introducer locking hub 30 and is moveable between a locked and unlocked position, thereby fixing the position of the introducer 6 and the sheath 8 and preventing movement therebetween, particularly during insertion into the patient. As will be described in more detail herein, the sheath locking system 18 keeps the introducer 6 from separating from the sheath 8 and prevents gaps from forming that can cause patient abrasions and unintended fluid flow between the introducer 6 and the sheath 8 during insertion.

[0099] FIGS. 2, 5A-5B and 6, and illustrate the locking sleeve 28 coupled to the introducer locking hub 30 and the sheath hub 20. As will be described in more detail herein, the locking sleeve 28 includes a guide 31 that engages a locking channel 38 provided on the introducer locking hub 30. The guide 31 moves within the locking channel 38 between an unlocked position, where the locking sleeve 28 is rotationally and axially movable with respect to the introducer locking hub 30, and a locked position (FIG. 2), where the locking sleeve 28 is axially fixed with respect to the introducer locking hub 30.

[0100] The locking sleeve 28 is illustrated, for example, in FIGS. 10A-10F. The locking sleeve 28 includes an elongated sleeve body 29 with a central lumen 56 extending longitudinally between the proximal end 58 and distal end 60 of the sleeve body 29. As provided in FIG. 6, the central lumen 56 defines a generally cylindrical inner surface 62 of the sheath locking sleeve 28. The central lumen 56 has a diameter of at least 0.3 inches. In some examples, the diameter ranges between 0.3 inches and 0.6 inches. Preferably, the diameter is about 0.40 inches. The distal end 60 of the sleeve body 29 also has afrustoconical outer surface 64 that tapers about the distal end 60 to help with positioning the locking sleeve 28 within the sheath hub 20 and abutting the seal assembly 24 (FIGS. 5B and 5B). The locking sleeve 28 also has a plurality of interference diameters 66 that extend radially from the outer surface of the sleeve body 29 around (all or a portion of) the circumference of the locking sleeve 28. As illustrated in FIGS. 5A and 6, the distal interference diameters 66 are sized and configured to engage corresponding recesses and / or slots 48 provided in the sheath hub 20 for securing the locking sleeve 28 to the sheath hub 20, and the distal interference diameter 66 seat against the proximal end of the sheath hub 20.

[0101] The locking sleeve 28 includes a guide 31 projecting from the outer surface 68 of the locking sleeve 28. The guide 31 engages a corresponding shaped locking channel 38 in the introducer locking hub 30. The guide 31 extends radially from the outer surface 68 and at least partially around the circumference of the outer surface 68. As provided in FIG. 6, the top surface of the guide 31 does not extend beyond the outer surface of the introducer locking hub 30 when the locking sleeve 28 and the introducer locking hub 30 are coupled. For example, the height of the guide 31 corresponds to the wall thickness of the introducer locking hub 30 proximate the guide when the locking sleeve 28 and the introducer locking hub 30 are coupled. In some examples, the top surface of the guide 31 is recessed with respect to the outer surface of the introducer locking hub 30. That is, the height of the guide 31 is less than the wall thickness of the introducer locking hub 30. In some examples, the height of the guide 31 is greater than a wall thickness of the introducer locking hub 30 such that the top surface of the guide 31 extends beyond the outer surface of the introducer locking hub 30 when the locking sleeve 28 and the introducer locking hub 30 are coupled. In some examples, the height / axial length of the guide 31 is between about 0.050 inches and about 0.10 inches. In some examples that height / axial length of the guide 31 is about 0.075 inches.

[0102] As illustrated in FIGS. 10D-10F, the guide 31 is a cylindrically shaped projection. However, it is contemplated that the guide 31 may have any other regular or irregular shape that would facilitate movement of the guide 31 within the locking channel 38 of the introducer locking hub 30. For example, the guide 31 may have an elongated hexagon shape. The guide 31 can have a diameter / width ranging from about 0.05 inches to about 0.20 inches. Preferably the guide 31 has a diameter / width of about 0.100 inches.

[0103] In general, the locking sleeve 28 can comprise polycarbonate, but in some examples, the locking sleeve 28 can comprise rigid plastic, or any other material suitable for providing a strong locking connector for an introducer 6 (metal, composite, etc.).

[0104] FIGS. 2-6 illustrate the introducer locking hub 30 coupled to the locking sleeve 28. FIGS. 8A-8F show the introducer locking hub 30 coupled to the introducer 6. FIGS. 9A-9F provide multiple view of the introducer locking hub 30. As described herein, the introducer 6 is fixedly coupled to the introducer locking hub 30. The introducer locking hub 30 couples with the locking sleeve 28 to fix the position the introducer 6 (axially and rotationally) with respect to the locking sleeve 28 / sheath 8. Each of the introducer 6 and introducer locking hub 30 are described in more detail as follows.

[0105] FIGS. 8A-8F illustrate the introducer locking hub 30 with the introducer 6 coupled thereto. Example introducer sheaths are described, for example in U.S. Patent Nos. 8,690,936 and 8,790,387, the disclosures of which are incorporated herein by reference. As provided in the cross-sectional views of FIGS. 5A and 5B, the introducer 6 is coupled to the introducer locking hub 30 and extends beyond the distal end of the introducer locking hub 30 body and into the sheath 8. When coupled to the sheath hub 20, the introducer 6 extends through the central lumen 56 of the locking sleeve 28, the sheath hub 20 and the central lumen of the sheath 8. As will be descried herein, the sheath 8 generally comprises a radially expandable tubular structure. Passage of the introducer 6 through the sheath 8 and into a patient’s vasculature causes the blood vessel to radially expand to about the diameter of the sheath 8. That is, the diameter of the central lumen of the sheath 8 is generally abuts the outer diameter of the introducer 6 such that the introducer 6 provides a mechanism to expand a patient’s vessel to accept the sheath.

[0106] As provided in FIGS. 8A-8F, the introducer 6 is formed as an elongate body with a central lumen extending therethrough. As shown in FIGS. 5A and 5B, the central lumen of the introducer is aligned with the central lumens of the introducer locking hub 30, the sheath hub 20 and the sheath 8. The introducer 6 is received within a recessed opening 39 provided on an interior surface of the introducer locking hub 30, the recessed opening 39 axially aligned with the central lumen 45 of the introducer locking hub 30. The introducer 6 is coupled to the introducer locking hub 30 at the recessed opening 39. In an example system, the introducer 6 has a diameter corresponding to, or less than, the diameter of the recessed opening 39. In some examples, the introducer 6 is fixedly coupled to the introducer locking hub 30 at the recessed opening 39. For example, the introducer 6 is coupled to the recessed opening 39 of the introducer locking hub 30 by at least one of a press fit, an interference fit, a snap fit, a mechanical fastener, a chemical fastener (for example, an adhesive), a weld, a thermal process, and / or any other suitable coupling process known in the art.

[0107] As described herein, the introducer 6 has a central lumen that aligns with the central lumen 45 of the introducer locking hub 30. This joined lumen allows for the passage of surgical equipment and / or medical devices to the treatment site (for example, a guide wire). In an example system, and as provided in FIGS. 5A and 5B, the central lumen of the introducer 6 has a diameter corresponding to at least a portion of the diameter of the central lumen 45 of the introducer locking hub 30. In general, the corresponding diameter portion is adjacent the distal end of the central lumen 45. In some examples, the diameter of the central lumen 45 at the distal end of the introducer locking hub 30 is slightly larger than the diameter of the central lumen passing through the introducer 6. The central lumen 45 can also define a decreasing tapered portion 41 between the proximal end and the distal end of the introducer locking hub 30 (see FIG. 6). The corresponding diameter portion and decreasing tapered portion 41 allows for smooth transition and delivery of surgical equipment and / or medical device through the introducer locking hub 30 and into the central lumen of the introducer 6.

[0108] As illustrated in FIGS. 9A-9F, the introducer locking hub 30 includes a introducer locking hub body 32 having a proximal end 70 and a distal end 72 and defining a central lumen 45 extending therethrough. The introducer locking hub body 32 has a first (middle) portion 33, a second (distal) portion 35 which extends distally from the first portion 33 and a third (proximal) portion 37 which extends proximally from the first portion 33. The first portion 33 includes the cylindrically-shaped recessed opening 39 for receiving and retaining the introducer 6 and an outer surface 43. In some examples, the recessed opening 39 has a diameter ranging between 0. 15 inches and about 0.25 inches. In some examples, the recessed opening 39 has a diameter ranging between 0.17 inches and about 0.20 inches. In some examples, the recessed opening has a diameter of about 0.194 inches.

[0109] The third (proximal) portion 37 of the introducer locking hub 30 includes the decreasing tapered portion 41 of the central lumen 45. The decreasing tapered portion 41 defining a frustoconical shape with decreasing taper / diameter from the proximal to the distal end of the sheath. It is contemplated that the tapered portion 41 has a minimum diameter of about 0.007 inches and a maximum diameter of about 0.194 inches.

[0110] As illustrated in FIGS. 5A and B, when coupled, the central lumen 56 of the locking sleeve 28 is aligned with the central lumen 45 of the introducer locking hub 30. In some examples, the central lumen 56 of the locking sleeve 28 is coaxial with the central lumen 45 of the introducer locking hub 30. When coupled, the proximal end of the locking sleeve 28 is received within the central lumen 45 of the introducer locking hub 30. The proximal end surface of the locking sleeve 28 is adjacent a shoulder 50 provided on an inner surface of thecentral lumen 45 of the introducer locking hub 30. As illustrated in FIGS. 5A and 5B, the central lumen 45 of the introducer locking hub 30 includes a first portion 52 having a first diameter adjacent the proximal end of the introducer locking hub 30, and a second portion 54 having a second, larger, diameter adjacent the distal end of the introducer locking hub 30. The recessed opening 39 can be considered either a component of the first portion 52 of the central lumen 45, or a separate component of the central lumen 45 located between the first (proximal) portion 52 and the second (distal) portion 54. When the locking sleeve 28 and introducer locking hub 30 are coupled, at least a portion of the sleeve body 29 of the locking sleeve 28 is received within the second portion 54 (larger portion) of the central lumen 45 of the introducer locking hub 30. The central lumen 56 of the locking sleeve 28 is aligned with the central lumen 45 of the introducer locking hub 30 such that they are co-axial and form a smooth inner surface along the combined central lumens of the introducer locking hub 30 and the locking sleeve 28.

[0111] As described herein, the locking sleeve 28 couples to the introducer locking hub 30 via engagement between the guide 31 on the locking sleeve 28 and the locking channel 38 provided in the introducer locking hub 30. As provided in FIGS. 9A-9F, the introducer locking hub 30 includes two locking channels 38. However, it is contemplated that the introducer locking hub 30 can include one locking channel 38 or more than two locking channels 38. The locking channel 38 can be is formed a recess or groove in a surface of the introducer locking hub 30, as a slotted opening, a clip, or as any other feature capable of receiving and securing the guide 31 projecting from the outer surface of the locking sleeve 28 with the introducer locking hub 30. Illustrated in FIG. 9B, the locking channels 38 provide an interface to secure the locking sleeve 28 to the introducer locking hub 30 and ensure a fixed axial position between the introducer 6 and the sheath 8.

[0112] The locking channel 38 is formed on the distal end of the introducer locking hub 30. The locking channel 38 includes an opening on the distal end surface that leads to an angled guide portion 40 that transitions to a locking portion 42. The guide portion 40 is configured to direct the guide 31 of the locking sleeve 28 in an axial and circumferential direction along the side wall of the guide portion 40 towards the locking portion 42 upon rotation of the introducer locking hub 30 and / or the locking sleeve 28. The locking portion 42 is configured to securely engage the guide 31, fixing the axial position of the introducer locking hub 30 with respect to the locking sleeve 28. As illustrated in FIG. 9B, the guide portion 40 of the locking channel 38 extends from the distal end of the introducer locking hub 30 axially towards the proximal end of the introducer locking hub 30 and circumferentially around theintroducer locking hub 30. For example, the guide portion 40 of the locking channel 38 can be described as extending helically around / along a length of the introducer locking hub 30 or on an angle from the distal end of the introducer locking hub 30.

[0113] As illustrated in FIGS. 9B and 9D, the locking portion 42 of the locking channel 38 extends at an angle from the end of the guide portion 40. As provided in FIG. 9B, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is greater than 90-degrees. In some examples, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is about 120-degrees. In an example system, the locking portion 42 extends around a portion of the circumference of the introducer locking hub 30. The locking portion 42 can extend parallel to the distal end of the introducer locking hub 30. In an example system, the length of the guide portion 40 (measured along its centerline) is greater than a length of the locking portion 42 (measured along its centerline). In some examples, the length of the guide portion 40 equals or is less than a length of the locking portion 42.

[0114] The locking portion 42 can include a catch 44 for securing the guide 31 within the locking portion 42 of the locking channel 38 and forming a partial barrier for the guide 31 within the locking portion 42. As illustrated in FIG. 9B, the catch 44 includes a projection that extends from a side wall 74 of the locking portion 42 and releasably secures the guide 31 within the locking channel 38. The catch 44 extends from the side wall 42a of the locking portion 42 in a proximal direction towards the center line of the locking portion 42 and has a height sufficient to retain the guide 31 between the catch 44 and the end of the locking portion 42.

[0115] The distal end surface 72 of the introducer locking hub 30 can include features for biasing the guide 31 towards and into the locking channel 38. For example, the distal end of the introducer locking hub 30 can include a tapered surface angled toward an opening of the locking channel 38. As illustrated in FIG. 9B, the distal end 72 of the introducer locking hub 30 includes a first tapered surface 76 (angled towards a leading edge of the opening of the locking channel 38 and a second tapered surface 78 angled towards the trailing edge of the opening of the locking channel 38.

[0116] In use, engagement between the guide 31 and the guide portion 40 of the locking channel 38 is configured to bias the locking sleeve 28 in a proximal axial direction toward the proximal end 70 of the introducer locking hub 30 (towards a locked position) when the locking sleeve 28 is rotated in a first axial direction. In this direction the guide 31 advances toward the locking portion 42 of the locking channel 38 into the locked position.Alternatively, engagement between the guide 31 and the locking portion 42 of the locking channel 38 is configured to bias the locking sleeve 28 in a distal axial direction toward the distal end of the introducer locking hub 30 (towards an unlocked position) when the locking sleeve 28 is rotated in a second (opposite) axial direction. In the second direction, the guide31 advances away from the locking portion 42 of the locking channel 38, to the unlocked position. When the guide 31 is in the locked position and retained with by locking portion 42 by catch 44, rotation in the second direction causes the guide 31 to bias against the catch 44 overcoming the oppositional forces of the catch 44, and moving the guide 1 from the locked to the unlocked position.

[0117] As illustrated in FIGS. 8A-9F, the outer surface of the introducer locking hub body32 includes gripping features and / or surfaces for a physician or technician to use when manipulating the introducer locking hub 30. As provided in FIG. 9B, the introducer locking hub body 32 can include a two recessed gripping surfaces 34 on opposite sides of the longitudinal axis of the introducer locking hub 30. When the introducer locking hub 30 is viewed from the side, the gripping surfaces 34 define a dog-bone / barbell shape to the hub body 32, i.e., a shape having a smaller diameter / width center portion and larger diameter / width end portions. In an example system, the gripping surfaces 34 are provided along at least 40% of the length of the introducer locking hub body 32. In some examples, the gripping surfaces 34 are provided along at least 50% of the length of the introducer locking hub body 32.

[0118] In general, the introducer locking hub 30 can comprise polycarbonate, but in some examples the introducer locking hub 30 can comprise rigid plastic, or any other material suitable for providing a locking mechanism for an introducer 6 (metal, composite, etc.).

[0119] As described herein, the introducer device / sheath assembly includes an expandable sheath 8 extending distally from the sheath hub 20. The expandable sheath 8 has a central lumen to guide passage of the delivery apparatus 10 for the medical device / prosthetic heart valve. In some examples, the introducer device / sheath assembly need not include the sheath hub 20. For example, the sheath 8 can be an integral part of a component of the sheath assembly, such as the guide catheter.

[0120] In certain examples, the expandable sheath 8 can comprise a plurality of coaxial layers extending along at least a portion of the length of the sheath 8. The structure of the coaxial layers is described in more detail herein with respect to FIGS. 11-23. Example expandable sheaths including coaxial layers are described, for example, in U.S. Patent Application No. 16 / 378,417, entitled “Expandable Sheath,’' and U.S. Patent Application No.17 / 716,882, entitled “Expandable Sheath,” the disclosures of which are herein incorporated by reference.

[0121] Various examples of the coaxial layered structure of the sheath 8 are described herein. For example, in reference to the example sheath 8 illustrated in FIGS. 11-14, the expandable sheath 8 can include a number of layers including an inner layer 102 (also referred to as an inner layer), a second layer 104 disposed around and radially outward of the inner layer 102, a third layer 106 disposed around and radially outward of the second layer 104, and a fourth outer layer 108 (also referred to as an outer layer) disposed around and radially outward of the third layer 106. In the illustrated configuration, the inner layer 102 can define the lumen 112 of the sheath extending along a central axis 114 through which the delivery apparatus travels into the patient’s vessel in order to deliver, remove, repair, and / or replace a prosthetic device, moving in a direction along the longitudinal axis of the sheath 8.

[0122] Referring to FIG. 12, when the sheath 8 is in an unexpanded state, various layers of the sheath, for example, the inner layer 102 and / or the outer layer 108, can form longitudinally-extending folds or creases such that the surface of the sheath comprises a plurality of folds or ridges 126. The ridges 126 can be circumferentially spaced apart from each other by longitudinally-extending valleys 128. When the sheath expands beyond its natural diameter DI, the ridges 126 and the valleys 128 can level out or be taken up as the surface radially expands and the circumference increases, as further described herein. When the sheath 8 collapses back to its natural diameter, the ridges 126 and valleys 128 can reform.

[0123] In certain examples, the inner layer 102 and / or the outer layer 108 can comprise a relatively thin layer of polymeric material. For example, the thickness of the inner layer 102 can be from 0.01 mm to 0.5 mm, 0.02 mm to 0.4 mm, or 0.03 mm to 0.25 mm. In some examples, the thickness of the outer layer 108 can be from 0.01 mm to 0.5 mm, 0.02 mm to 0.4 mm, or 0.03 mm to 0.25 mm.

[0124] In certain examples, the inner layer 102 and / or the outer layer 108 can comprise a lubricious, low-friction, and / or relatively non-elastic material. For example, the inner layer 102 and / or the outer layer 108 can comprise a polymeric material having a modulus of elasticity of 400 Mpa or greater. Exemplary materials can include ultra-high-molecular- weight polyethylene (UHMWPE) (for example, Dyneema®), high-molecular-weight polyethylene (HMWPE), or polyether ether ketone (PEEK). With regard to the inner layer 102 in particular, such low coefficient of friction materials can facilitate passage of the prosthetic device through the lumen 112. Other suitable materials for the inner and outer layers can include polyimide, polytetrafluoroethylene (PTFE), expandedpolytetrafluoroethylene (ePTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyamide, polyether block amide (for example, Pebax), and / or combinations of any of the above. In some examples, the sheath 8 can include a lubricious liner on the inner surface of the inner layer 102. Examples of suitable lubricious liners include materials that can further reduce the coefficient of friction of the inner layer 102, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for a lubricious liner also include other materials desirably having a coefficient of friction of 0.1 or less.

[0125] Additionally, some examples of the sheath 8 can include an exterior hydrophilic coating on the outer surface of the outer layer 108. Such a hydrophilic coating can facilitate insertion of the sheath 8 into a patient’s vessel, reducing potential damage. Examples of suitable hydrophilic coatings include the Harmony™ Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM medical coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings (for example, PTFE, polyethylene, poly vinylidene fluoride), are also suitable for use with the sheath 8. Such hydrophilic coatings may also be included on the inner surface of the inner layer 102 to reduce friction between the sheath and the delivery apparatus, thereby facilitating use and improving safety. In some examples, a hydrophobic coating, such as Perylene, may be used on the outer surface of the outer layer 108 or the inner surface of the inner layer 102 in order to reduce friction.

[0126] In certain examples, the second layer 104 can be a braided layer. FIGS. 13A and 13B illustrate the sheath 8 with the outer layer 108 removed to expose the elastic third layer 106. With reference to FIGS. 13A and 13B, the braided second layer 104 can comprise a plurality of members or filaments 110 (for example, metallic or synthetic wires or fibers) braided together. The braided second layer 104 can have any desired number of filaments 110, which can be oriented and braided together along any suitable number of axes. For example, with reference to FIG. 13B, the filaments 110 can include a first set of filaments 110A oriented parallel to a first axis A, and a second set of filaments HOB oriented parallel to a second axis B. The filaments 110A and HOB can be braided together in a biaxial braid such that filaments 110A oriented along axis A form an angle 0 with the filaments 110B oriented along axis B. In certain examples, the angle 0 can be from 5° to 70°, 10° to 60°, 10° to 50°, or 10° to 45°. In the illustrated example, the angle 0 is 45°. In some examples, the filaments 110 can also be oriented along three axes and braided in a triaxial braid, or oriented along any number of axes and braided in any suitable braid pattern. The braided second layer 104 can extend along substantially the entire length L of the sheath 8, or alternatively, can extend onlyalong a portion of the length of the sheath. In particular examples, the filaments 110 can be wires made from metal (for example, Nitinol, stainless steel, etc.), or any of various polymers or polymer composite materials, such as carbon fiber. In certain examples, the filaments 110 can be round, and can have a diameter of from 0.01 mm to 0.5 mm, 0.03 mm to 0.4 mm, or 0.05 mm to 0.25 mm. In some examples, the filaments 110 can have a flat cross-section with dimensions of 0.01 mm x 0.01 mm to 0.5 mm x 0.5 mm, or 0.05 mm x 0.05 mm to 0.25 mm x 0.25 mm. In one aspect, filaments 110 having a flat cross-section can have dimensions of 0.1 mm x 0.2 mm. However, other geometries and sizes are also suitable for certain aspects. If braided wire is used, the braid density can be varied. Some examples have a braid density of from ten picks per inch to eighty picks per inch, and can include eight wires, sixteen wires, or up to fifty-two wires in various braid patterns. In some examples, the second layer 104 can be laser cut from a tube, or laser-cut, stamped, punched, etc., from sheet stock and rolled into a tubular configuration. The second layer 104 can also be woven or knitted, as desired.

[0127] The third layer 106 can be a resilient, elastic layer (also referred to as an elastic material layer). In certain examples, the elastic third layer 106 can be configured to apply radially inward force to the underlying inner layer 102 and second layer 104 in a radial direction (for example, toward the central axis 114 of the sheath) when the sheath expands beyond its natural diameter by passage of the delivery apparatus through the sheath. Stated differently, the elastic third layer 106 can be configured to apply encircling / radially inward pressure to the layers of the sheath beneath the elastic third layer 106 to counteract expansion of the sheath. The radially inwardly directed force is sufficient to cause the sheath to collapse radially back to its unexpanded state after the delivery apparatus is passed through the sheath.

[0128] In the illustrated example, the elastic third layer 106 can comprise one or more members configured as strands, ribbons, or elastic bands 116 helically wrapped around the braided second layer 104. For example, in the illustrated aspect the elastic third layer 106 comprises two elastic bands 116A and 116B wrapped around the braided second layer 104 with opposite helicity, although the elastic layer may comprise any number of bands depending upon the desired characteristics. The elastic bands 116A and 116B can be made from, for example, any of a variety of natural or synthetic elastomers, including silicone rubber, natural rubber, any of various thermoplastic elastomers, polyurethanes such as polyurethane siloxane copolymers, urethane, plasticized polyvinyl chloride (PVC), styrenic block copolymers, polyolefin elastomers, etc. In some examples, the elastic layer can comprise an elastomeric material having a modulus of elasticity of 200 MPa or less. In some examples, the elastic third layer 106 can comprise a material exhibiting an elongation tobreak of 200% or greater, or an elongation to break of 400% or greater. The elastic third layer 106 can also take other forms, such as a tubular layer comprising an elastomeric material, a mesh, a shrinkable polymer layer such as a heat-shrink tubing layer, etc. In lieu of, or in addition to, the elastic third layer 106, the sheath 8 may also include an elastomeric or heat-shrink tubing layer around the outer layer 108. Examples of such elastomeric layers are disclosed in U.S. Publication No. 2014 / 0379067, U.S. Publication No. 2016 / 0296730, and U.S. Publication No. 2018 / 0008407, which are incorporated herein by reference. In some examples, the elastic third layer 106 can also be radially outward of the polymeric outer layer 108.

[0129] In certain examples, one or both of the inner layer 102 and / or the outer layer 108 can be configured to resist axial elongation of the sheath 8 when the sheath expands. More particularly, one or both of the inner layer 102 and / or the outer layer 108 can resist stretching against longitudinal forces caused by friction between a prosthetic device and the inner surface of the sheath 8 such that the length L remains substantially constant as the sheath expands and contracts. As used herein with reference to the length L of the sheath, the term “substantially constant” means that the length L of the sheath increases by not more than 1%, by not more than 5%, by not more than 10%, by not more than 15%, or by not more than 20%. Meanwhile, with reference to FIG. 13B, the filaments 110A and HOB of the braided second layer 104 can be allowed to move angularly relative to each other such that the angle 0 changes as the sheath expands and contracts. This, in combination with the longitudinal ridges 126 in the inner layer 102 and outer layer 108, can allow the lumen 112 of the sheath to expand as a prosthetic device is advanced through it.

[0130] For example, the inner layer 102 and the outer layer 108 can be heat-bonded during the manufacturing process such that the braided second layer 104 and the elastic third layer 106 are encapsulated between the inner layer 102 and outer layer 108. More specifically, in some examples the inner layer 102 and the outer layer 108 can be adhered to each other through the spaces between the filaments 110 of the braided second layer 104 and / or the spaces between the elastic bands 116. The inner layer 102 and outer layer 108 can also be bonded or adhered together at the proximal and / or distal ends of the sheath. In some examples, the inner layer 102 and outer layer 108 are not adhered to the filaments 110. This can allow the filaments 110 to move angularly relative to each other, and relative to the inner layer 102 and outer layer 108, allowing the diameter of the braided second layer 104, and thereby the diameter of the sheath, to increase or decrease. As the angle 0 between the filaments 110A and HOB changes, the length of the braided second layer 104 can alsochange. For example, as the angle 0 increases, the braided second layer 104 can foreshorten, and as the angle 0 decreases, the braided second layer 104 can lengthen to the extent permitted by the areas where the inner layer 102 and outer layer 108 are bonded. However, because the braided second layer 104 is not adhered to the inner layer 102 and outer layer 108, the change in length of the braided layer that accompanies a change in the angle 0 between the filaments 110A and HOB does not result in a significant change in the length L of the sheath.

[0131] FIG. 14 illustrates radial expansion of the sheath 8 as a prosthetic device (for example, implant 12) is passed through the sheath 8 in the direction of arrow 132 (for example, distally). As the prosthetic device (implant 12) is advanced through the sheath 8, the sheath can resiliently expand to a second diameter D2 that corresponds to a size or diameter of the prosthetic device. As the prosthetic device (implant 12) is advanced through the sheath 8, the prosthetic device can apply longitudinal force to the sheath in the direction of motion by virtue of the frictional contact between the prosthetic device and the inner surface of the sheath. However, as noted herein, the inner layer 102 and / or the outer layer 108 can resist axial elongation such that the length L of the sheath remains constant, or substantially constant. This can reduce or prevent the braided layer second 104 from lengthening, and thereby constricting the lumen 112.

[0132] Meanwhile, the angle 0 between the filaments 110A and HOB can increase as the sheath expands to the second diameter D2 to accommodate the prosthetic valve. This can cause the braided second layer 104 to foreshorten. However, because the filaments 110 are not engaged or adhered to the inner layer 102 or outer layer 108, the shortening of the braided second layer 104 attendant to an increase in the angle 0 does not affect the overall length L of the sheath. Moreover, because of the longitudinally-extending ridges 126 formed in the inner layer 102 and outer layer 108, the inner layer 102 and outer layer 108 can expand to the second diameter D2 without rupturing, in spite of being relatively thin and relatively nonelastic. In this manner, the sheath 8 can resiliently expand from its natural diameter DI to a second diameter D2 that is larger than the diameter DI as a prosthetic device is advanced through the sheath, without lengthening, and without constricting. Thus, the force required to push the prosthetic implant through the sheath is significantly reduced.

[0133] Additionally, because of the radial force applied by the elastic third layer 106, the radial expansion of the sheath 8 can be localized to the specific portion of the sheath occupied by the prosthetic device. For example, with reference to FIG. 14, as the prosthetic device (implant 12) moves distally through the sheath 8, the portion of the sheath immediatelyproximal to the prosthetic device (for example, implant 12) can radially collapse back to the initial diameter DI under the influence of the elastic third layer 106. The inner layer and outer layer 108 can also buckle as the circumference of the sheath is reduced, causing the ridges 126 and the valleys 128 to reform. This can reduce the size of the sheath required to introduce a prosthetic device of a given size. Additionally, the temporary, localized nature of the expansion can reduce trauma to the blood vessel into which the sheath is inserted, along with the surrounding tissue, because only the portion of the sheath occupied by the prosthetic device expands beyond the sheath’s natural diameter and the sheath collapses back to the initial diameter once the device has passed. This limits the amount of tissue that must be stretched in order to introduce the prosthetic device, and the amount of time for which a given portion of the vessel must be dilated.

[0134] In some examples layered sheath 8 structure, FIGS. 15-23 illustrate various features of the coaxial layered structure of the expandable sheath 8 of FIG. 1 according to another aspect. Similar reference numbers are used to describe like elements. It is to be understood that the variations (for example, materials and alternate configurations) described herein with reference to FIGS. 11-14 can also apply to the example shown in FIGS. 15-23. Furthermore, the variations described herein with reference to FIGS. 15-23 can also be applied to the sheath described in FIGS. 11-14.

[0135] Similar to various examples of the sheath 8 described herein in reference to FIGS. 11- 14, the sheath 8 of FIGS. 15-23 includes a plurality of layers. For example, the sheath 8 illustrated in FIGS. 15-23, also includes an inner layer 202 and an outer layer 204 disposed around the inner layer 202. The inner layer 202 can define a central lumen 212 through which the delivery apparatus travels into the patient’ s vessel in order to deliver, remove, repair, and / or replace a prosthetic device, moving in a direction along the longitudinal axis X. Similar to the sheath illustrated in FIGS. 11-14, as the prosthetic device passes through the sheath 8, the sheath 8 locally expands from a first, resting / unexpanded diameter to a second, expanded diameter to accommodate the prosthetic device. After the prosthetic device passes through a particular location of the sheath 8, each successive expanded portion or segment of the sheath 8 at least partially returns to the smaller, resting / unexpanded diameter. In this manner, the sheath 8 can be considered self-expanding, in that it does not require use of a balloon, dilator, and / or obturator to expand.

[0136] Similar to the examples herein, the inner and outer layers 202, 204 can comprise any suitable materials. Suitable materials for the inner layer 202 include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyether block amide(for example, Pebax), and / or combinations thereof. In an example sheath 8, the inner layer 202 can comprise a lubricious, low-friction, or hydrophilic material, such as PTFE. Such low coefficient of friction materials can facilitate passage of the prosthetic device through the lumen defined by the inner layer 202. In some examples, the inner layer 202 can have a coefficient of friction of less than about 0.1. Some examples of the sheath 8 can include a lubricious liner on the inner surface of the inner layer 202. Examples of suitable lubricious liners include materials that can further reduce the coefficient of friction of the inner layer 202, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for a lubricious liner also include other materials desirably having a coefficient of friction of about 0.1 or less.

[0137] Suitable materials for the outer layer 204 include nylon, polyethylene, Pebax, HDPE, polyurethanes (for example, Tecoflex), and other medical grade materials. In one example, the outer layer 204 can comprise high density polyethylene (HDPE) and Tecoflex (or other polyurethane material) extruded as a composite. In some examples, the Tecoflex can act as an adhesive between the inner layer 202 and the outer layer 204 and may only be present along a portion of the inner surface of the outer layer 204. Other suitable materials for the inner and outer layers are also disclosed in U.S. Patent Nos. 8,690,936 and 8,790,387, which are incorporated herein by reference.

[0138] Additionally, some examples of the sheath 8 include an exterior hydrophilic coating on the outer surface of the outer layer 204. Such a hydrophilic coating can facilitate insertion of the sheath 8 into a patient’s vessel. Examples of suitable hydrophilic coatings include the Harmony TM Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings available from SurModics, Inc., Eden Prairie, MN. DSM medical coatings (available from Koninklijke DSM NV, Heerlen, the Netherlands), as well as other hydrophilic coatings (for example, PTFE, polyethylene, poly vinylidene fluoride), are also suitable for use with the sheath 8.

[0139] FIGS. 15-23 illustrate an example sheath system 200. FIG. 16 provides a partial cross-section of the distal end of the sheath 8 along section line 16-16 identified in FIG. 15. As described herein, the sheath 8 can be inserted into a vessel (for example, the femoral or iliac arteries) by passing through the skin of patient, such that a soft tip portion 206 at the distal end 210 of the sheath 8 is inserted into the vessel. As best seen in FIG. 16, the soft tip portion 206 can comprise, in some examples, low density polyethylene (LDPE) and can be configured to minimize trauma or damage to the patient’s vessels as the sheath is navigated through the vasculature. For example, the soft tip portion 206 can be slightly tapered tofacilitate passage through the vessels. The soft tip portion 206 can be secured to the distal end 210 of the sheath 8, such as by thermally bonding the soft tip portion 206 to the inner and outer layers of the sheath 8. Such a soft tip portion 206 can be provided with a lower hardness than the other portions of the sheath 8. In some examples, the soft tip portion 206 can have a Shore hardness from about 25D to about 40D. The soft tip portion 206 is configured to be radially expandable to allow a prosthetic device to pass through the distal opening of the sheath 8. For example, the soft tip portion 206 can be formed with a weakened portion, such as an axially extending score line or perforated line that is configured to split and allow the soft tip portion 206 to expand radially when the prosthetic device passes therethrough.

[0140] FIG. 17 shows a cross-sectional view of the sheath 8 taken near the distal end 210 of the sheath 8 as indicated by section line 17-17 in FIG. 16. As illustrated in FIGS. 16 and 17, the sheath 8 can include at least one radiopaque filler or marker, such as a discontinuous, or C-shaped, band / marker 216 positioned near the distal end 210 of the sheath 8. The marker 216 can be associated with the inner and / or outer layers 202, 204 of the sheath 8. For example, as shown in FIG. 17, the marker 216 can be positioned between the inner layer 202 and the outer layer 204. In some examples, the marker 216 can be associated with the outer surface of the outer layer 204. In some examples, the marker 216 can be embedded or blended within the inner or outer layers 202, 204.

[0141] FIGS. 18 and 19 show additional cross-sections taken at different points along the sheath 8. FIG. 18 shows a cross-section of a segment of the sheath near the proximal end 214 of the sheath 8, as indicated by section line 18-18 in FIG. 15. At this location, the sheath 8 includes the inner layer 202, outer layer 204, elastic outer layer 250 / outer jacket, and the strain relief layer 26. At this location, near the proximal end of the sheath 8, the inner and outer layers 202, 204 are substantially tubular. Here the inner and outer layers 202, 204 can be formed without any slits or folded portions in the layers. By contrast, as described herein, the inner and outer layers 202, 204 at different locations along the sheath 8 (for example, at the point indicated by section line 19-19 in FIG. 15 and / or the point indicated by section line 22-22 in FIG. 21) can have a different configuration.

[0142] As shown in FIG. 19, the inner layer 202 can be arranged to form a substantially cylindrical central lumen 212 therethrough. Inner layer 202 can include one or more folded portions 218. In the example shown in FIG. 19, inner layer 202 is arranged to have one folded portion 218 that can be positioned on either side of the inner layer 202. Inner layer 202 can be continuous, in that there are no breaks, slits, or perforations in inner layer 202.Outer layer 204 can be arranged in an overlapping fashion such that an overlapping portion 220 overlaps at least a part of the folded portion 218 of the inner layer 202. As shown in FIG. 19, the overlapping portion 220 also overlaps an underlying portion 222 of the outer layer 204. The underlying portion 222 can be positioned to underlie both the overlapping portion 220 of the outer layer 204, as well as the folded portion 218 of the inner layer 202. Thus, the outer layer 204 can be discontinuous, in that it includes a slit or a cut in order to form the overlapping portion 220 and underlying portion 222. In other words, a first edge 224 of the outer layer 204 is spaced apart from a second edge 225 of the outer layer 204 so as not to form a continuous layer.

[0143] As shown in FIG. 19, the sheath 8 can also include a thin layer of bonding or adhesive material 228 positioned between the inner layer 202 and outer layer 204. In one example, the adhesive material 228 can comprise a polyurethane material such as Tecoflex. The adhesive material 228 can be positioned on an inner surface 230 of at least a portion of the outer layer 204 so as to provide adhesion between selected portions of the inner layer 202 and outer layer 204. For example, the outer layer 204 may only include a Tecoflex layer (adhesive material 228) around the portion of the inner surface 230 that faces the lumen-forming portion of the inner layer 202. In other words, the Tecoflex layer (adhesive material 228) can be positioned so that it does not contact the folded portion 218 of the inner layer 202 in some examples. In some examples, the Tecoflex can be positioned in different configurations as desired for the particular application. For example, as shown in FIG. 19, the Tecoflex layer can be positioned along the entire inner surface 230 of the outer layer 204. In some examples, the Tecoflex layer can be applied to the outer surface of the inner layer 202 instead of the inner surface of the outer layer 204. The Tecoflex layer can be applied to all or selected portions on the inner layer 202; for example, the Tecoflex layer can be formed only on the portion of the inner layer 202 that faces the lumen-forming portion of the outer layer 204 and not on the folded portion 218. The configuration of FIG. 19 allows for radial expansion of the sheath 8 as an outwardly directed radial force is applied from within (for example, by passing a medical device such as a prosthetic heart valve through the central lumen 212). As radial force is applied, the folded portion 218 can at least partially separate, straighten, and / or unfold, and / or the overlapping portion 220 and the underlying portion 222 of the outer layer 204 can slide circumferentially with respect to one another, thereby allowing the diameter of central lumen 212 to enlarge.

[0144] In this manner, the sheath 8 is configured to expand from a resting / unexpanded configuration (FIG. 19) to an expanded configuration shown in FIG. 20. In the expandedconfiguration, as shown in FIG. 20, a gap 232 can form between the longitudinal edges of the overlapping portion 220 and the underlying portion 222 of the outer layer 204. As the sheath 8 expands at a particular location, the overlapping portion 220 of the outer layer 204 can move circumferentially with respect to the underlying portion 222 as the folded portion 218 of the inner layer 202 unfolds. This movement can be facilitated by the use of a low-friction material for inner layer 202, such as PTFE. Further, the folded portion 218 can at least partially separate and / or unfold to accommodate a medical device having a diameter larger than that of central lumen 212 in the resting / unexpanded configuration. As shown in FIG. 20, in some examples, the folded portion of the inner layer 202 can completely unfold, so that the inner layer 202 forms a cylindrical tube at the location of the expanded configuration.

[0145] Similar to the example sheath 8 in FIG. 14, the sheath 8 is configured to locally expands at a particular location corresponding to the location of the medical device along the length of the central lumen 212, and then locally contracts once the medical device has passed that particular location. Thus, a bulge may be visible, traveling longitudinally along the length of the sheath 8 as a medical device is introduced through the sheath 8, representing continuous local expansion and contraction as the device travels the length of the sheath 8. Each segment of the sheath 8 will locally contract after removal of any radial outward force such that the sheath 8 at least partially returns to the original resting / unexpanded diameter of central lumen 212. Similar to the example sheath described herein, an elastic outer layer 250 can (optionally) be provided along the sheath 8, urging the inner and outer layers 202, 204 back to the unexpanded configuration.

[0146] The layers 202, 204 of sheath 8 can be configured having the folded portion 218 as shown in FIG. 19 along at least a portion of the length of the sheath 8. In some examples, the inner and outer layers 202, 204 can be configured as shown in FIG. 19 along the length A (FIG. 15) such that the folded portion 218 extends from a location adjacent the soft tip portion 206 to a location closer to the proximal end 214 of the sheath 8, adjacent and / or under the distal end of the strain relief layer 26. In this matter, the sheath 8 is expandable and contractable only along a portion of the length of the sheath corresponding to length A (which can correspond to the section of the sheath inserted into the narrowest section of the patient’s vasculature).

[0147] In some examples, the folded portion 218 portion extends from a location adjacent the soft tip portion 206 under the strain relief layer 26, as illustrated in FIG. 21. In this example, the folded structure of the inner layer 202 extends from the soft tip portion 206, under the strain relief layer 26 and along the tapered portion 248 of the strain relief layer 26.

[0148] FIGS. 22 and 23 illustrate cross-sectional views of the sheath 8 taken along the strain relief layer 26 at section line 22-22 in FIG. 21. In this example, the folded portion 218 of the inner layer 202 extends under the strain relief layer 26. FIG. 22 shows a cross-section of the sheath 8 in a resting / unexpanded configuration having an inner diameter DI. FIG. 23 shows a cross-section of the sheath 8 in a (partially) expanded configuration, having an inner diameter D2, where D2 is greater than DI.

[0149] As shown in FIGS. 22-23, in some examples, the overlapping portion 220 does not overlap the entire folded portion 218 of the inner layer 202, and thus a portion of the folded portion 218 can be directly adjacent to the strain relief layer 26 in locations where the strain relief layer 26 is present. In locations where the strain relief layer 26 is not present, part of the folded portion 218 may be visible from the outside of the sheath 8, as seen in FIG. 21 (and / or visible through an elastic outer layer 250 described in more detail herein). In these examples, the sheath 8 can include a longitudinal seam 234 where the overlapping portion 220 terminates at the folded portion 218. In use, the sheath 8 can be positioned such that the seam 234 is posterior to the point of the sheath that is 180 degrees from the seam 234 (for example, facing downward in the view of FIG. 21). As shown in FIG. 21, the seam 234 need not extend the entire length of the sheath 8, and end at a transition point between portions of the sheath having a folded inner layer and portions of the sheath not having a folded inner layer.

[0150] In some examples, the folded portion 218 can include a weakened portion 236, such as a longitudinal perforation, score line, and / or slit, along at least a portion of the length of the inner layer 202. The weakened portion 236 / slit allows for the two adjacent ends 238, 240 of the folded portion 218 / inner layer 202 to move relative to one another as the sheath 8 expands to the expanded configuration shown in FIG. 23. For example, the sheath 8 locally expands as a medical device is inserted therethrough, causing the weakened portion 236 to split / separate.

[0151] In each of the example sheaths 8 described herein, the sheath 8 may include an elastic outer layer 250 that expands with the sheath 8. The elastic outer layer 250 can provide an inwardly directed radial force that directs the sheath to a folded / unexpanded configuration. Similar to the strain relief layer 26, elastic outer layer 250 can also provide hemostasis (for example, prevent blood loss during implantation of the prosthetic device).

[0152] The elastic outer layer 250 can be positioned around at least a portion of the strain relief layer 26, outer layer 108, 204 and / or the inner layers of the sheath 8. As illustrated in FIGS. 21-23, the elastic outer layer 250 can surround the entire circumference of outer layer204, and can extend longitudinally along any portion of the length of the sheath 8, including along (over or under) the strain relief layer 26. The elastic outer layer 250 extends for a length along at least a portion of the main body of the sheath 8. In some examples, the elastic outer layer 250 extends to a point adjacent the distal end 210, or can extend all the way to the distal end 210 of sheath 8. For example, the elastic outer layer 250 extends over the entire length of the sheath 8.

[0153] As shown in FIGS. 17-20, 22 and 23, the elastic outer layer 250 can be a continuous tubular layer, without slits or other discontinuities. The elastic outer layer 250 extends between strain relief layer 26 and the outer surface of the outer layer 204. In some examples, the elastic outer layer 250 extends over the outer surface of the strain relief layer 26 and the outer surface of the outer layer 204. In some examples, the elastic outer layer 250 extends both over the strain relief layer 26 and / or between the outer layer of the sheath 8 and the strain relief layer 26.

[0154] The elastic outer layer 250 can comprise any pliable, elastic material(s) that expand and contract, preferably with a high expansion ratio. Preferably, the materials used can include low durometer polymers with high elasticity, such as Pebax, polyurethane, silicone, and / or polyisoprene. Materials for the elastic outer layer 250 can be selected such that it does not impede expansion of the inner and outer layers of the sheath 8. The elastic outer layer 250 can have a thickness ranging from, for example, about 0.001 inches to about 0.010 inches. In some examples, the elastic outer layer 250 can have a thickness of about 0.003 inches to about 0.006 inches. The elastic outer layer 250 can be configured to stretch and expand as the sheath expands, as shown in the expanded configuration in FIG. 20.

[0155] As illustrated in FIGS. 2, 15, and 21, the sheath 8 in each of the examples described herein may include a strain relief layer 26. The strain relief layer 26 is provided adjacent the proximal end of the sheath 8 and extends along / over the outer surface of the sheath 8. In some examples, the strain relief layer 26 is provided over the outer layer 108, 204 of the sheath 8. The strain relief layer 26 forms a smooth transition between the sheath hub 20 and the sheath 8 and facilitates mating of the sheath 8 with the sheath hub 20.

[0156] Additionally, and as will be described in more detail herein, the strain relief layer 26 provides a region of higher durometer or stiffness that restricts expansion of the underlying sheath layers. This helps to ensure hemostasis between the portions of the sheath 8 inside the patient and the sheath hub (external to the patient). The increased durometer and / or stiffness along the strain relief layer 26 prevents blood from flowing between the various layers of the sheath 8 exterior to the patient during the procedure, helping to withstand the blood pressurethat would otherwise cause the sheath to “balloon up” with body fluid / blood. Additionally, the strain relief layer 26 can be sized and configured to form a seal with the patient’s artery when inserted, such that blood is substantially prevented from flowing between the strain relief layer 26 and the vessel wall. For example, although the strain relief layer 26 does not extend all the way to the distal end 210 of the sheath 8, the strain relief layer 26 can extend distally enough along the sheath 8 that when the sheath 8 is fully inserted into the patient a portion of the strain relief layer 26 extends through and seals against the arteriotomy site.

[0157] As described herein, the strain relief layer 26 is provided over the outer layer 108, 204 of the sheath 8. The strain relief layer 26 can be bonded to the outer layer 108, 204 to prevent the strain relief layer 26 from sliding over the outer layer and “bunching up” in response to the friction forces applied by the surrounding tissue during insertion of the sheath 8 into the patient’s vasculature. For example, the strain relief layer 26 can be bonded at the proximal end and / or distal end of the outer layer 108, 204. At the proximal and distal ends, the strain relief layer 26 can be bonded to the outer layer 204 around the full circumference of the outer layer. At the distal end of the sheath 8, the strain relief layer 26 can additionally and / or alternatively be bonded to the inner layer(s) of the sheath 8. For example, the strain relief layer 26 can be bonded to the distal end surface of the inner layer 102, 202.

[0158] FIGS. 18, 22 and 23 illustrate cross-sectional views of the sheath 8 along the strain relief layer 26. FIG. 18 shows a cross-section of a segment of the sheath near the proximal end 214 of the sheath 8, as indicated by line 18-18 in FIG. 15. Similarly, FIGS. 22 and 23 show cross-section segments of various example sheaths near the proximal end 214 of the sheath 8 and closer to the distal end of the strain relief layer 26, as indicated by section line 22-22 in FIG. 21. As illustrated in each of FIGS. 15-23, the sheath 8 at this location can comprise a liner / inner layer 202, outer layer 204, adhesive material 228, an optional elastic outer layer 250, and the strain relief layer 26.

[0159] The strain relief layer 26 extends circumferentially around at least a portion of the inner layer 202 and outer layer 204. The strain relief layer 26 extends from the proximal end 214 of the sheath 8 towards the distal end 210 of the sheath 8. As shown in FIG. 21 (and FIG. 15), the strain relief layer 26 extends for a length L along at least a portion of the main body of the sheath 8. In some examples, the strain relief layer 26 extends to a point adjacent the distal end 210, or can extend all the way to the distal end 210 of sheath 8. In some examples, the longitudinal length L of the strain relief layer 26 can range from about 10 cm to the entire length of the sheath 8.

[0160] The strain relief layer 26 extends to / adjacent the proximal end 214 of the sheath 8 and provides a compression fit over the distal end of the sheath hub 20 thereby coupling the sheath 8 to the sheath hub 20. Additionally, or alternatively, the strain relief layer 26 secured between the sheath hub 20 and the sheath hub cap 22 or other fastening device for by coupling the proximal end of the sheath to the sheath hub 20. In some examples, the strain relief layer 26 does not extend all the way to the proximal end 214 of the sheath 8.

[0161] It is understood that strain relief layer 26, as shown herein, can have similar composition and characteristics of the inner and outer layers as disclosed herein. Various compositions are disclosed, for example, in Application No. PCT / US2021 / 301275, entitled “Expandable sheath for introducing an endovascular delivery device into a body,” the disclosure of which is herein incorporated by reference.

[0162] The strain relief layer 26 can comprise any lubricious, low-friction, and / or relatively non-elastic material. Preferably the materials used can include high durometer polymers, with low elasticity. In some examples, the strain relief layer 26 is composed of the same and / or similar material to the inner layer 202 and / or outer layer 204. For example, as described herein regarding the inner layer 102 and / or outer layer 108, exemplary materials can include polyurethane (for example, high density polyethylene), ultra-high-molecular- weight polyethylene (UHMWPE) (for example, Dyneema®), high-molecular-weight polyethylene (HMWPE), or poly ether ether ketone (PEEK). Other suitable materials strain relief layer 26 can include polyimide, polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyamide, polyether block amide (for example, Pebax), and / or combinations of any of the herein. Materials for the strain relief layer 26 can be selected such that it impedes expansion of the underlying layers of the sheath 8.

[0163] The strain relief layer 26 can have a thickness ranging from, for example, about 0.001 inches to about 0.010 inches. In some examples, the strain relief layer 26 can have a thickness of from about 0.003 inches to about 0.006 inches. The wall thickness is measured radially between the inner surface of the strain relief layer 26 and the outer surface of the strain relief layer 26.

[0164] In some examples, the material composition and / or wall thickness can change along the length of the strain relief layer 26. For example, the strain relief layer 26 can be provided with one or more segments, where the composition and / or thickness changes from segment to segment. In an example aspect, the Durometer rating of the composition changes along the length of the strain relief layer 26 such that segments near the proximal end comprise a stiffermaterial or combination of materials, while segments near the distal end comprise a softer material or combination of materials. Similarly, the wall thickness of the strain relief layer 26 in segments near the proximal end can be thicker / greater than the wall thickness of the elastic outer layer 250 near the distal end.

[0165] As illustrated in FIGS. 15 and 21, the strain relief layer 26 has a proximal end and a distal end and a central lumen extending longitudinally therethrough. The strain relief layer 26 includes a generally tubular shaped proximal portion 242 adjacent the proximal end of the strain relief layer 26, and a generally tubular shaped distal portion 246 adjacent the distal end of the strain relief layer 26. The strain relief layer 26 includes a frustoconical shaped tapered portion 248 extending between the proximal portion 242 and the distal portion 246 of the strain relief layer 26, such that the diameter of the strain relief layer 26 at the proximal portion 242 is greater than the diameter of the strain relief layer 26 at the distal portion 246 of the strain relief layer 26. The tapered portion 248 and the flared proximal portion 242 help ease the transition of the medical device / delivery apparatus when passing between the larger diameter sheath hub 20 to the smaller diameter of the sheath 8.

[0166] As described herein, the strain relief layer 26 is made of a material that is stiffer than the other sheath 8 layers such that the strain relief layer 26 inhibits expansion of the portion of the sheath disposed along / under the strain relief layer 26. Because radial expansion is limited along the strain relief layer 26, higher push forces are necessary to advance the medical device through the central lumen of the sheath 8. In some examples, the highest push forces through the sheath 8 are experienced near the proximal and distal ends of the sheath 8, through the strain relief layer 26 (for example, through the tapered portion of the strain relief layer 26), and at proximal and distal ends of the strain relief layer 26.

[0167] As described herein, it is desirable to reduce push forces required to insert the medical device / delivery apparatus through the central lumen of the sheath 8. In some examples, the thickness and / or composition of the strain relief layer 26 and / or sheath 8 can be adjusted to improve the performance of the sheath 8 and reduce the push force. In some examples, dilating or expanding the sheath 8 (or a portion thereof) before the medical device / delivery apparatus is introduced helps to reduce the initial push force through the sheath 8. Predilating the sheath 8 releases and / or loosens any bonding or adhesion of the sheath 8 layers that occurs during the manufacturing process, for example, bonding between the inner and outer layers 202, 204, bonding between the folded portion 218 and outer layer 204, bonding between the inner / outer layers and the strain relief layer 26. Pre-dilating can also break or separate the weakened portion 236 of folded portion 218 of the inner layer 202, separatingadjacent ends 238, 240 of the folded portion 218, as described herein and illustrated in FIG. 23. With the sheath 8 layers able to move freely with respect to the other, the medical device / delivery apparatus is pushed through the sheath 8 lumen at a much lower force.

[0168] FIGS. 24-44 illustrate a loader 300 that can be used with the delivery apparatus 10 or other sheath systems. The loader 300 is both peelable and flushable. Flushing the loader 300 and the loaded delivery apparatus 10 removes air bubbles without requiring backfill and the ability to remove the loader tube (i.e., peelable) reduces the impact and space claim of the loader 300 during use of the delivery apparatus 10 after advancement into the sheath 8.

[0169] It is contemplated that the sheath 8 discussed above can be used with the loader 300 and can include the layered sheath structure described herein in reference FIGS. 4-7 and 11- 23, and / or any other sheath structure disclosed herein.

[0170] As shown in FIG. 24, a loader 300 with a sealing architecture split into two internal seals arranged to provide a flushable interior that maintains fluid around the delivery apparatus 10 within the loader 300 while also making a loader tube that is peelable and / or otherwise easily removable after the delivery apparatus 10 is advanced into the sheath 8. The loader 300 includes a housing in the form of a loader cap 304, a flush port 308 for providing fluid into the loader cap 304, a loader tube 312 sized to receive a sheath (for example, the sheath 8 discussed above), and a hub 316 engaged with the loader cap 304 that holds the loader tube 312 to the loader cap 304.

[0171] As shown in FIGS. 25 and 26, the loader 300 also includes a distal retention ring 320 engaged with the loader cap 304, a distal loader seal 324 forming a seal between the loader tube 312 and the loader cap 304, and a proximal loader seal 328 sealed to the loader cap 304 by a proximal retention ring 332.

[0172] As shown in FIG. 27, the loader tube 312 includes a distal tube extension 334 that is generally cylindrical, a loader tube taper 336, a loader tube ferrule 340 sized to be received by the hub 316 and generally cylindrical, a loader tube seal taper 344 that is bonded to the hub 316, a loader tube seal extension 348 sized to sealingly engage distal loader seal 324, and a severance feature 352 that allows the loader tube 312 to be removed from the loader 300.In some examples, the loader tube 312 is formed of polytetrafluoroethylene (PTFE). In some examples, the loader tube 312 is bonded to the hub 316 with an adhesive. In some examples, the loader tube 312 is sized so that the transcatheter heart valve sits in the narrowest part of the hub 316 so as to provide a smooth transition between the balloon and the transcatheter heart valve. In some examples, the loader tube 312 defines a minimum interior diameter of 0.2 inches to 0.4 inches. In some examples, the loader tube 312 defines a minimum interiordiameter of 0.255 inches to 0.320 inches. In some examples, the loader tube 312 defines a minimum interior diameter of 8 millimeters to 10 millimeters. In some examples, the loader tube 312 defines a minimum interior diameter that is sized to cooperate with a catheter of 6 French to 24 French. Additionally, the loader tube 312 applies a slight compression to the transcatheter heart valve and the balloon. The loader tube 312 keeps the transcatheter heart valve hydrated on a back table protecting the transcatheter heart valve before it is advanced through the sheath 8 and into the patient. In some examples, the severance feature 352 includes separation lines, parting lines, a controlled weakness feature, or another structure that aids in the removal of the loader tube 312 during use. The severance feature 352 shown in FIG. 27 includes two slits cut through the loader tube seal extension 348, the loader tube seal taper 344, and at least a portion of the loader tube ferrule 340. In some examples, the severance feature 352 is sized to extend only within the hub 316. In some examples, the severance feature 352 extends past the loader tube ferrule 340 into the loader tube taper 336 and / or the distal tube extension 334. In some examples, the severance feature 352 is cut fully through a proximal end of the loader tube 312 and includes a perforation and / or weakened groove toward a distal end of the loader tube 312.

[0173] As shown in FIG. 28, the hub 316 includes a hub support 356 that extends distally and is sized to engage and support the loader tube ferrule 340. In some examples, the hub support 356 is adhered to the loader tube ferrule 340. The hub 316 includes a hub cutout 362 sized allow removal of the severance feature 352 therethrough. In some examples, the severance feature 352 defines a width between two slits and the hub cutout 362 is equal to or greater than the width of the severance feature 352. A hub seal extension 366 extends axially toward a proximal end of the hub 316. A hub seal surface 370 is shaped to engage the loader tube seal taper 344 of the loader tube 312. In some examples, the hub seal surface 370 is adhered to the loader tube seal taper 344. The hub 316 also includes a hub thread 374 that is shaped to engage the loader cap 304. In some examples, the hub 316 is formed from polycarbonate.

[0174] As shown in FIGS. 29 and 30, the distal retention ring 320 includes a distal ring thread 378 sized to engage the loader cap 304, a distal ring inner surface 382 sized to allow the distal loader seal 324 to flex and the sheath 8 and delivery apparatus 10 to pass therethrough, a distal ring engagement feature 384 that aid a user in tightening the distal retention ring 320 into the loader cap 304, and a distal ring sealing surface 386 shaped to engage the distal loader seal 324 and hold it is sealing engagement with the loader cap 304.

[0175] As shown in FIGS. 31-33, the distal loader seal 324 includes a distal seal axial extension 390 sized to engage an outer surface of the loader tube seal extension 348, a distalseal inner lip 394 shaped to engage with a proximal end of the loader tube 312, and the distal seal inner lip 394 defines a distal seal aperture 398 that is sized to receive the sheath 8 and the delivery apparatus 10 while allowing flow-by flushing. In some examples, the distal seal aperture 398 defines a diameter of 5 millimeters to 13 millimeters. In some examples, the distal seal aperture 398 defines a diameter of 0.310 inches to 0.320 inches. In some examples the distal seal aperture 398 defines a diameter of 8 millimeters. In some examples, the distal seal aperture 398 is sized to allow flow between the catheter and the distal loader seal 324 when the catheter is 6 French to 24 French.

[0176] Flushing the loader 300 and the loaded delivery apparatus 10 removes air bubbles without requiring backfill. The distal loader seal 324 also includes a distal seal compression surface 402 shaped to engage the distal ring sealing surface 386 of the distal retention ring 320. A distal seal outer lip 406 extends proximally from a distal seal gasket surface 410 shaped to sealingly engage the loader cap 304. In some examples, the distal loader seal 324 includes a distal seal severance feature 414 that corresponds with the severance feature 352 of the loader tube 312 so that at least a portion of the distal loader seal 324 is removable with the loader tube 312.

[0177] As shown in FIGS. 34-36, the loader cap 304 includes a distal head 418 (for example, a hex head) that is graspable by a tool to aid in engagement of the loader cap 304 during manipulation, a distal head thread 422 is sized to engage the hub 316 and the distal retention ring 320, a distal seal seat 426 sized to engage the distal seal outer lip 406 and the distal seal gasket surface 410 of the distal loader seal 324, a flush aperture 430 sized to receive the flush port 308, a proximal head 434 in the form of a hex head that is graspable by a tool to aid in engagement of the loader cap 304 during manipulation, a proximal thread 438, a proximal seal seat 442, and a flush cavity 446 formed between the distal seal seat 426 and the proximal seal seat 442. The distal seal seat 426 includes a groove sized to receive the axially extending distal seal outer lip 406. The proximal seal seat 442 includes a groove sized to receive an axially extending proximal seal outer lip 454 discussed below.

[0178] As shown in FIGS. 37 and 38, the proximal loader seal 328 includes a proximal seal gasket surface 450 sized to sealingly engage the proximal seal seat 442 of the loader cap 304, a proximal seal outer lip 454 sized to sealingly engage the proximal seal seat 442, and a proximal seal inner lip 456 defining a proximal seal aperture 458 sized for an interference fit with the guide catheter 14. In some examples, the proximal seal aperture 458 defines a diameter of 2.2 millimeters to 3.2 millimeters. In some examples, the proximal seal aperture 458 defines a diameter of 2.74 millimeters. In some examples, the proximal seal aperture 458defines a diameter of 0.105 inches to 0.111 inches. In some examples, the proximal seal aperture 458 defines a diameter of 0. 108 inches. In some examples, the proximal seal aperture 458 is sized to seal with a catheter of 6 French to 24 French.

[0179] The engagement of the proximal seal aperture 458 with the guide catheter 14 inhibits backflow of fluid toward a proximal side of the loader 300. The proximal loader seal 328 also includes a proximal seal compression surface 462 that is engagable by the proximal retention ring 332 to maintain the proximal loader seal 328 in sealing engagement with the loader cap 304. In some examples, the proximal seal aperture 458 defines a 2 mm diameter.

[0180] As shown in FIGS. 39 and 40, the proximal retention ring 332 includes a proximal ring sealing surface 466 shaped to engage the proximal seal compression surface 462 of the proximal loader seal 328, a proximal ring inner surface 470, a proximal ring thread 474 sized to engage the proximal thread 438 of the loader cap 304, and a proximal ring engagement feature 478 that is structured to be engageable by a user to tighten the proximal retention ring 332 within the proximal thread 438.

[0181] As shown in FIG. 41, the flush port 308 includes a flush port body 482, a Luer connection 486, and a flush port thread 490 sized to engage the flush aperture 430.

[0182] A method includes inserting the delivery apparatus 10 (for example, the transcatheter heart valve and the balloon) into the loader 300, as shown in FIG. 42. The assembled loader 300 and delivery apparatus 10 are then inserted into the sheath hub 24 so that the loader tube 312 extends through the distal seal 24c, the intermediate seal 24b, and the proximal seal 24a of the seal assembly 24. The delivery apparatus 10 can then be advanced into the sheath 8. With the delivery apparatus 10 successfully advanced into the sheath 8, the user can back the loader 300 proximally out of the seal assembly 24 and remove the loader tube 312 via the severance feature 352 while the delivery apparatus 10 remains within the sheath 8. In some examples, the user grasps a portion of the loader tube 312 between the severance feature 352 and withdrawing or otherwise peeling the loader tube 312 away from the remaining portions of the loader 300. In some examples, the user severs or otherwise separates the loader tube 312 along the severance feature 352 (for example, the loader tube 312 can be cut or scored along the severance feature 352). With the severance feature 352 released, the loader tube 312 can be withdrawn or otherwise peeled off of loader 300. In some examples, a portion of the distal loader seal 324 is also removed. For example, the distal seal severance feature 414 can be used to peel the distal loader seal 324 or a portion of the distal loader seal 324 away from the remaining components of the loader 300. The hub 316 is then unthreaded from the loader cap 304 and removed from the assembly via the hub cutout 362. With the loader tube312 and the hub 316 removed, the loader 300 is slid distally into engagement with the locking sleeve 28, as shown in FIG. 43. Once the loader cap 304 is positioned, and the delivery apparatus 10 is pushed distally, the loader occupies a minimal amount of axial length and the procedure continues as shown in FIG. 44.

[0183] The introducer 6 and sheath 8 as described herein are provided. The distal end of the introducer 6 is inserted into the proximal end of the sheath 8 and advanced with the central lumen of the sheath 8 as shown in FIG.2. The introducer 6 is advanced within the central lumen of the sheath 8 in a distal direction toward the distal end of the sheath 8.

[0184] In some examples as described herein, the introducer 4 is coupled to the sheath 8 such that the axial and / or rotational position of the introducer 6 with respect to the sheath 8 is fixed. This prevents gapping between the introducer 6 and the sheath 8 during insertion reduces the risk of trauma to the patient’s vasculature.

[0185] In some examples, a sheath locking sleeve 28 is coupled to the proximal end of the sheath hub 20 as described herein. In some examples, the introducer 6 is coupled to the sheath 8 by advancing the introducer 6 advanced distally within the sheath locking sleeve 28 and at least partially within the sheath 8 such that the introducer locking hub 30 is positioned adjacent a proximal end of the sheath locking sleeve 28. The introducer 6 is further advanced within the sheath locking sleeve 28 such that the guide 31 projecting from the outer surface of the sheath locking sleeve 28 is received within the corresponding opening to the locking channel 38.

[0186] The introducer locking hub 30 is then rotated in a first direction with respect to the sheath locking sleeve 28 to move the guide 31 along the locking channel 38 into a locked position. For example, moving the guide 31 into the locked position includes rotating the introducer locking hub 30 to move the guide 31 along a guide portion 40 of the locking channel 38 toward a locking portion 42. Further rotation of the introducer locking hub 30 directs the guide 31 into the locking portion 42 of the locking channel 38, the locking portion 42 configured to securely engage the guide 31 and fix the axial position of the introducer locking hub 30 with respect to the sheath locking sleeve 28. Where the locking channel 38 includes a catch 44, rotation of the introducer locking hub 30 in the first direction causes the guide 31 to overcome the bias force of the catch 44 and advance the guide 31 beyond the catch 44 into the locking portion 42, where the catch 44 secures the guide 31 within the locking portion 42 thereby fixing the axial location of the sheath 8 with respect to the introducer 6.

[0187] The sheath 8 and introducer 6 are least partially inserted into the patient’s blood vessel and advanced to the treatment site. In some examples, the expandable sheath 8 is inserted into the femoral artery or other vessels of the patient’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 patient to pass therethrough by itself. Also, the vasculature may be too fragile to receive the delivery apparatus without the use of an introducer sheath 8. The use of the combined sheath 8 and introducer 6, allows for a smaller diameter sheath to be used, thereby reducing the push force needed to advance the sheath 8 / introducer 6 into and through the patient’s blood vessel is reduced helping to minimize trauma to the vessel.

[0188] In some examples, a guidewire is optionally positioned at the treatment site and the sheath 8 and introducer 6 are advanced over the guidewire.

[0189] Once the combined sheath 8 and introducer 6 are positioned at the treatment site, the introducer 6 is then withdrawn in a proximal direction within the central lumen of the sheath 8. To remove the introducer 6, the introducer locking hub 30 is rotated is a second, opposite, direction with respect to the sheath locking sleeve 28. Rotating the introducer locking hub 30 in the second direction causes the guide 31 to slide along the locking channel 38, from the locking portion 42 toward the guide portion 40. In particular, rotating of the introducer locking hub 30 in the second direction directs the guide 31 out of the locking portion 42 of the locking channel 38 and through the guide portion 40 and releases the introducer locking hub 30 from the sheath locking sleeve 28. Where the locking channel 38 includes a catch 44, rotation of the introducer locking hub 30 in the second direction causes the guide 31 to overcome the bias force of the catch 44 and advance from the locking portion 42 to the guide portion 40 of the locking channel 38. As a result, the guide 31 slides out of the locking channel 38 into the unlocked position.

[0190] The introducer locking hub 30 is then disengaged from the sheath locking sleeve 28 and the introducer 6 is withdrawn from the central lumen of the sheath 8 to allow the delivery apparatus to advance there through. For example, with the central lumen of the sheath 8 clear, the medical device (for example, implant 12) is advanced within the central lumen of the sheath 8 via the loader 300 and beyond the distal opening to the treatment site within the blood vessel and / or heart tissue.

[0191] In some examples as described herein, the sheath 8 and / or strain relief layer 26 are sized and configured locally expand as the medical device is advanced therethrough. Forexample, in some examples the sheath 8 and / or strain relief layer 26 can expanded from an unexpanded configuration at a first 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 of the sheath 8 / strain relief layer 26.

[0192] In some examples, the medical device is contracted or compressed radially as it passes through the strain relief layer 26, from the proximal portion 242, through the tapered portion 248 and into the smaller diameter distal portion 246. As the medical device and delivery apparatus are advanced through the strain relief layer 26, they exert an outwardly directed radial force against the central lumen of the sheath 8, causing the strain relief layer 26 (and corresponding portion of the sheath 8) proximate the medical device / delivery apparatus to locally expand from an unexpanded configuration to an expanded configuration.

[0193] The medical device is then advanced beyond the distal end 27 of the strain relief layer 26, into the lumen of the sheath 8 beyond the strain relief layer 26. As the medical device is advanced through the sheath 8 beyond the strain relief layer 26, the sheath 8 locally expands from the unexpanded configuration 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 inner layer / central lumen 212 of the sheath 8. In some examples, the sheath 8 corresponds to the layered sheath 8 structure described in reference to FIGS. 11-23. The sheath 8 includes an inner layer and / or outer layer, and a folded portion, for example, ridges 126 and valleys 128 of the fourth (outer) layer 108 (FIGS. 11-14), and folded portion 218 of the inner layer 202 (FIGS. 15-23). Locally expanding the lumen of the layered sheath 8 causes a length of the folded portion to at least partially unfold. Similarly, locally contracting the sheath 8 at least partially back to the unexpanded configuration causes a length of the folded portion to urge back to a folded configuration. For example, in reference to the sheath 8 of FIGS. 15-23, the outer layer is a discontinuous outer layer and includes an overlapping portion (for example, overlapping portion 220) and an underlying portion (for example, underlying portion 222). With the sheath 8 in the unexpanded configuration, the folded portion 218 is disposed between the overlapping portion 220 overlaps the underlying portion 222 (FIG. 19). As the sheath 8 locally expands to the expanded configuration, a length of the overlapping portion 220 moves circumferentially with respect to the underlying portion 220, at least partially unfolding the folded portion 218. As illustrated in FIG. 20, when the layered sheath is fully expanded, the inner layer 202 extends into the gap 232formed between the longitudinal edges of the overlapping portion 220 and the underlying portion 222 of the outer layer 204.

[0194] As the medical device passes through the lumen of the sheath 8 / strain relief layer 26, the sheath 8 / strain relief layer 26 locally contracts at least partially back to the unexpanded configuration when the medical device has passed. When used to deliver a medical device within a patient, the medical device is then passed through the distal opening of the sheath 8 and delivered to the treatment site. The position of the medical device can be moved or adjusted until the medical device is adequately positioned within the patient.

[0195] With the medical device delivered to the treatment site, any delivery apparatus / components coupled to the medical device are then removed from the medical device and withdrawn from / through the central lumen 212 of the sheath 8. In some examples, withdrawing the medical device from the central lumen 212 of the sheath 8 further includes locally contracting the sheath 8 at least partially back to the unexpanded configuration as the medical device passes through the central lumen 212. For example, in some aspects, the sheath 8 includes an elastic outer layer 250 that extends at least partially over the outer layer and / or the strain relief layer 26. The elastic outer layer 250 locally expands and contracts as the medical device is advanced through the lumen of the sheath 8. In some examples, the elastic outer layer 250 urges the various layers of the sheath 8 to an unexpanded configuration.

[0196] In some examples, accessing the treatment site may require creating an opening in the heart tissue (for example, foramen ovalis) of the patient. In some examples, a cutting instrument can be advanced through the sheath 8 to create an opening in the patient’s heart tissue. The medical device (implant 12) is advanced beyond the distal end / opening of the sheath 8 delivered to the treatment site. In some procedures, a curved approach to the treatment site is desirable. For example, during a transseptal approach for mitral valve replacement / repair. Mitral valve diseases are among the most prevalent valvular heart diseases and necessitate surgical procedures for the repair or replacement of this valve. Conventional left atriotomy is the standard approach for most surgeons. However, the transseptal approach can confer better exposure to the mitral valve in cases where the left atrium is small, where there are adhesions caused by previous procedures, where there are associated operations requiring right atriotomy, and where there is beating heart surgery. In the transseptal approach, the right atrium is opened and a longitudinal incision (approximately 4 cm) made in the middle of the foramen ovalis on the intra-atrial septum. The septal edges are then pulled in order to expose the mitral valve fully. Conventionally adilator and / or shunt is required to expand the opening, a shunt can also be used to close the opening and provide an access point for future procedures. However, a major drawback of the transseptal approach surrounds the risk associated with expanding the incision, maintaining the expanded opening the foramen ovalis and the use of a shunt for closing the opening. The sheath of the present disclosure allows for the local and temporary expansion of the incision site only during delivery of the prosthetic device through the incision site.

[0197] With the medical device delivered to the treatment site, the sheath 8 is then withdrawn from the patient’s blood vessel and the opening in the blood vessel and skin closed.

[0198] In some examples, the medical device / implant 12 is a prosthetic device mounted in a radially crimped state on a delivery apparatus, and advancing the prosthetic device through the central lumen of the sheath 8 includes advancing the delivery apparatus and the prosthetic device through central lumen of the sheath 8 and into a vasculature of the patient. In some examples, the prosthetic device comprises a prosthetic heart valve and the method further comprises implanting the prosthetic heart valve at a treatment site within the patient. In some examples, the prosthetic heart valve is mounted on a balloon catheter of the delivery apparatus as the prosthetic heart valve is advanced through the sheath 8. In some examples, the sheath 8 is inserted into a femoral artery of the patient.

[0199] EXEMPLARY ASPECTS

[0200] 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.

[0201] Example 1. A loader system comprising: a cap including a flush aperture; an proximal loader seal engaged with the cap and defining an proximal seal aperture configured to receive a delivery system; a distal loader seal engaged with the cap and defining a distal seal aperture configured to receive the delivery system, wherein the cap, the proximal loader seal, and the distal loader seal define a flush cavity in fluid communication with the flush aperture; a hub rotatably engaged with the cap and defining a cutout; and a loader tube engaged with the distal loader seal, the loader tube supported by the hub and including a severance feature configured to aid removal of the loader tube from the loader system.

[0202] Example 2. The loader system of example 1, the cap includes a proximal seal seat shaped to sealingly engage the proximal loader seal, and a distal seal seat shaped to sealingly engage the distal loader seal.

[0203] Example 3. The loader system of example 2, wherein the flush cavity is formed between the proximal seal seat and the distal seal seat.

[0204] Example 4. The loader system of any one of examples 1-3, wherein the proximal seal aperture is configured to seal against a catheter to inhibit backflow of fluid.

[0205] Example 5. The loader system of any one of examples 1 -3, wherein the proximal seal aperture defines a diameter of 2.2 millimeters to 3.2 millimeters.

[0206] Example 6. The loader system of any one of examples 1-3, wherein the proximal seal aperture is configured to seal with a catheter of 6 fr to 24 fr.

[0207] Example 7. The loader system of any one of examples 1-6, wherein the distal seal aperture defines a diameter of 5 millimeters to 13 millimeters.

[0208] Example 8. The loader system of any one of examples 1-6, wherein the distal seal aperture is configured to allow flow past the distal seal when used with a catheter of 6 fr to 24 fr.

[0209] Example 9. The loader system of any one of examples 1-8, wherein the distal loader seal includes an axially extending distal seal outer lip sized to engage a groove of the cap.

[0210] Example 10. The loader system of any one of examples 1-9, wherein the distal loader seal includes an axial extension sized to sealingly engage the loader tube.

[0211] Example 11. The loader system of example 10, wherein the axial extension defines a diameter larger than the distal seal aperture.

[0212] Example 12. The loader system of example 10, wherein the axial extension is cylindrical and extends axially to engage the loader tube.

[0213] Example 13. The loader system of any one of examples 1-12, further comprising: an proximal retention ring engaged with the cap and maintaining the proximal loader seal in engagement with the cap; and a distal retention ring engaged with the cap and maintaining the distal loader seal in engagement with the cap.

[0214] Example 14. The loader system of example 13, wherein the cap includes proximal threads sized to engage the proximal retention ring, and wherein the cap includes distal threads sized to engage the distal retention ring.

[0215] Example 15. The loader system of any one of examples 1-14, wherein the hub is threadingly engaged with the cap.

[0216] Example 16. The loader system of any one of examples 1-15, wherein the cap defines a continuous distal cap thread, the loader system further comprising a distal retention ring threadingly engaged with the continuous distal cap thread and maintaining the distal loader seal in engagement with the cap, wherein the hub is threadingly engaged with the continuous distal cap thread.

[0217] Example 17. The loader system of any one of examples 1-16, wherein the cutout defines a width of 9 millimeters to 10 millimeters.

[0218] Example 18. The loader system of any one of examples 1-17, wherein the hub is configured for removal from the delivery system.

[0219] Example 19. The loader system of any one of examples 1-18, wherein the cutout corresponds to a size of the severance feature of the loader tube.

[0220] Example 20. The loader system of any one of examples 1-19, wherein the cutout is configured to allow removal of the hub from the loader system with the delivery system in place.

[0221] Example 21. The loader system of any one of examples 1-20, wherein the hub includes a hub support that extends axially and is shaped to support the loader tube.

[0222] Example 22. The loader system of example 1-21, wherein the loader tube is adhered to the hub.

[0223] Example 23. The loader system of any one of examples 1-22, wherein the loader tube defines an minimum interior diameter of 0.2 inches to 0.4 inches.

[0224] Example 24. The loader system of any one of examples 1-22, wherein the loader tube is configured to work with a catheter of 6 fr to 24 fr.

[0225] Example 25. The loader system of any one of examples 1-24, wherein the loader tube is formed from a lubricious plastic.

[0226] Example 26. The loader system of any one of examples 1-25, wherein the loader tube defines an outer diameter configured to be received within an introducer sheath.

[0227] Example 27. The loader system of any one of examples 1-26, wherein the severance feature includes two slits formed adjacent the hub and extending partially along an axial length of the loader tube.

[0228] Example 28. The loader system of example 1-27, wherein the severance feature extends along less than an entirety of an axial length of the loader tube.

[0229] Example 29. The loader system of any one of examples 1-28, wherein the severance feature defines a tab width less than a width of the cutout of the hub.

[0230] Example 30. An introducer and loader system comprising: an introducer including: an introducer housing; an introducer sheath extending from the introducer housing; and an introducer seal assembly positioned within the introducer housing and providing selective access to the introducer sheath via the introducer housing; and a loader including: a cap defining a proximal seal seat and a distal seal seat, the cap including a flush aperture positioned between the proximal seal seat and the distal seal seat; a proximal loader seal engaged with the proximal seal seat and defining a proximal seal aperture; a distal loader seal engaged with the distal seal seat and defining a distal seal aperture larger than the proximal seal aperture; and a loader tube engaged with the distal loader seal, the loader tube sized to be received within the introducer sheath and including a severance feature configured to aid removal of the loader tube from the loader.

[0231] Example 31. A minimally-invasive prosthetic heart valve delivery system, comprising: an introducer sheath having a lumen therethrough of no greater than 24 French; a balloon catheter having a balloon on a distal end, the balloon catheter further including a steering mechanism for deflecting the distal end; a balloon-expandable prosthetic heart valve crimped over the balloon, wherein an outer dimension of the balloon catheter having the prosthetic heart valve thereon is small enough to pass through the introducer sheath lumen; the steering mechanism including a deflecting segment on the balloon catheter located just proximal to the balloon; and a loader between the introducer sheath and the balloon catheter providing an effective fluid seal against egress of blood through the introducer sheath in an absence or a presence of different sized medical implements, the loader including: a cap including a flush aperture; a proximal loader seal engaged with the cap and defining an proximal seal aperture configured to receive a delivery system; a distal loader seal engaged with the cap and defining a distal seal aperture configured to receive the delivery system, wherein the cap, the proximal loader seal, and the distal loader seal define a flush cavity in fluid communication with the flush aperture; a hub rotatably engaged with the cap and defining a cutout; and a loader tube engaged with the distal loader seal and sized to be received within the introducer sheath, the loader tube supported by the hub and including a severance feature configured to aid removal of the loader tube from the loader.

[0232] Example 32. The minimally-invasive prosthetic heart valve delivery system of example 31, wherein the minimally-invasive prosthetic heart valve delivery system is preloaded in a packaged state.

[0233] Example 33. A method for loading a prosthetic heart valve within a delivery apparatus, comprising: positioning a distal end of an introducer sheath in a femoral artery, aproximal end of the introducer sheath connected to a handle of the introducer sheath; securing the prosthetic heart valve to a retaining mechanism of the delivery apparatus, wherein the prosthetic heart valve comprises an expandable frame member and a plurality of leaflets; pushing the prosthetic heart valve through an upstream loader seal of a loader, through a flush cavity of the loader, through a downstream loader seal of the loader, and into a loader tube of the loader to radially compress the prosthetic heart valve; flushing the flush cavity via a flush port formed in the loader between the upstream loader seal and the downstream loader seal; inserting the loader tube into the introducer sheath; progressing the retaining mechanism of the delivery apparatus distally into the introducer sheath within the femoral artery; and removing the loader tube via a severance feature of the loader tube.

[0234] Example 34: A method of loading a prosthetic heart valve within a delivery apparatus according to any example herein, particularly example 33, wherein removing the loader tube from the loader includes: grasping portion of the loader tube proximate the severance feature; and withdrawing the loader tube from the loader causing the loader tube to separate along the severance feature.

[0235] Example 35: A method of loading a prosthetic heart valve within a delivery apparatus according to any example herein, particularly examples 33-34, wherein removing the loader tube from the loader includes: separating the loader tube along the severance feature; and withdrawing the loader tube from the loader.

[0236] In view of the many possible aspects to which the principles of the disclosed disclosure can be applied, it should be recognized that the illustrated aspects are only preferred examples of the disclosure and should not be taken as limiting the scope of the disclosure. Rather, the scope of the disclosure is defined by the following claims. We, therefore, claim as our disclosure all that comes within the scope and spirit of these claims.

Claims

WHAT IS CLAIMED:

1. A loader system comprising: a cap including a flush aperture; a proximal loader seal engaged with the cap and defining a proximal seal aperture configured to receive a delivery system; a distal loader seal engaged with the cap and defining a distal seal aperture configured to receive the delivery system, wherein the cap, the proximal loader seal, and the distal loader seal define a flush cavity in fluid communication with the flush aperture; a hub rotatably engaged with the cap and defining a cutout; and a loader tube engaged with the distal loader seal, the loader tube supported by the hub and including a severance feature configured to aid removal of the loader tube from the loader system.

2. The loader system of claim 1, the cap includes a proximal seal seat shaped to sealingly engage the proximal loader seal, and a distal seal seat shaped to sealingly engage the distal loader seal.

3. The loader system of claim 2, wherein the flush cavity is formed between the proximal seal seat and the distal seal seat.

4. The loader system of any one of claims 1-3, wherein the proximal seal aperture is configured to seal against a catheter to inhibit backflow of fluid.

5. The loader system of any one of claims 1-4, wherein the distal loader seal includes an axially extending distal seal outer lip sized to engage a groove of the cap.

6. The loader system of any one of claims 1-5, wherein the distal loader seal includes an axial extension sized to sealingly engage the loader tube.

7. The loader system of claim 6, wherein the axial extension defines a diameter larger than the distal seal aperture and where the axial extension is cylindrical and extends axially to engage the loader tube.

8. The loader system of any one of claims 1-7, further comprising: an proximal retention ring engaged with the cap and maintaining the proximal loader seal in engagement with the cap; and a distal retention ring engaged with the cap and maintaining the distal loader seal in engagement with the cap.

9. The loader system of claim 8, wherein the cap includes proximal threads sized to engage the proximal retention ring, wherein the cap includes distal threads sized to engage the distal retention ring.

10. The loader system of any one of claims 1-9, wherein the cap defines a continuous distal cap thread, the loader system further comprising a distal retention ring threadingly engaged with the continuous distal cap thread and maintaining the distal loader seal in engagement with the cap, wherein the hub is threadingly engaged with the continuous distal cap thread.

11. The loader system of any one of claims 1-10, wherein the cutout is configured to allow removal of the hub from the loader system with the delivery system in place.

12. The loader system of any one of claims 1-11, wherein the hub includes a hub support that extends axially and is shaped to support the loader tube.

13. The loader system of claim 1-12, wherein the loader tube is adhered to the hub.

14. The loader system of any one of claims 1-13, wherein the severance feature includes two slits formed adjacent the hub and extending partially along an axial length of the loader tube, wherein the severance feature extends along less than an entirety of an axial length of the loader tube.

15. The loader system of any one of claims 1-14, wherein the severance feature defines a tab width less than a width of the cutout of the hub.

16. An introducer and loader system comprising: an introducer including: an introducer housing; an introducer sheath extending from the introducer housing; and an introducer seal assembly positioned within the introducer housing and providing selective access to the introducer sheath via the introducer housing; and a loader including: a cap defining a proximal seal seat and a distal seal seat, the cap including a flush aperture positioned between the proximal seal seat and the distal seal seat; a proximal loader seal engaged with the proximal seal seat and defining a proximal seal aperture; a distal loader seal engaged with the distal seal seat and defining a distal seal aperture larger than the proximal seal aperture; anda loader tube engaged with the distal loader seal, the loader tube sized to be received within the introducer sheath and including a severance feature configured to aid removal of the loader tube from the loader.

17. A minimally-invasive prosthetic heart valve delivery system, comprising: an introducer sheath having a lumen therethrough of no greater than 24 French; a balloon catheter having a balloon on a distal end, the balloon catheter further including a steering mechanism for deflecting the distal end; a balloon-expandable prosthetic heart valve crimped over the balloon, wherein an outer dimension of the balloon catheter having the prosthetic heart valve thereon is small enough to pass through the introducer sheath lumen; the steering mechanism including a deflecting segment on the balloon catheter located just proximal to the balloon; and a loader between the introducer sheath and the balloon catheter providing an effective fluid seal against egress of blood through the introducer sheath in an absence or a presence of different sized medical implements, the loader including: a cap including a flush aperture; a proximal loader seal engaged with the cap and defining an proximal seal aperture configured to receive a delivery system; a distal loader seal engaged with the cap and defining a distal seal aperture configured to receive the delivery system, wherein the cap, the proximal loader seal, and the distal loader seal define a flush cavity in fluid communication with the flush aperture; a hub rotatably engaged with the cap and defining a cutout; and a loader tube engaged with the distal loader seal and sized to be received within the introducer sheath, the loader tube supported by the hub and including a severance feature configured to aid removal of the loader tube from the loader.

18. The minimally-invasive prosthetic heart valve delivery system of claim 17, wherein the minimally-invasive prosthetic heart valve delivery system is preloaded in a packaged state.

19. A method for loading a prosthetic heart valve within a delivery apparatus, comprising: positioning a distal end of an introducer sheath in a femoral artery, a proximal end of the introducer sheath connected to a handle of the introducer sheath; securing the prosthetic heart valve to a retaining mechanism of the delivery apparatus, wherein the prosthetic heart valve comprises an expandable frame member and a plurality of leaflets;pushing the prosthetic heart valve through an upstream loader seal of a loader, through a flush cavity of the loader, through a downstream loader seal of the loader, and into a loader tube of the loader to radially compress the prosthetic heart valve; flushing the flush cavity via a flush port formed in the loader between the upstream loader seal and the downstream loader seal; inserting the loader tube into the introducer sheath; progressing the retaining mechanism of the delivery apparatus distally into the introducer sheath within the femoral artery; and removing the loader tube via a severance feature of the loader tube.

20. The method of claim 19, wherein removing the loader tube from the loader includes: grasping portion of the loader tube proximate the severance feature; and withdrawing the loader tube from the loader causing the loader tube to separate along the severance feature.

21. The method of any one of claims 19-20, wherein removing the loader tube from the loader includes: separating the loader tube along the severance feature; and withdrawing the loader tube from the loader.

Images