Expandable sheath gasket provides homeostasis

Abstract

An introducer sheath system (1200), comprising: a gasket (1202) disposed about an outer surface of a dual-layer sheath (100), the gasket providing a radially inward force on the sheath to seal the outer layer (110) of the sheath against the inner layer (108) of the sheath to prevent fluid flow therebetween.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 280,251, filed November 17, 2021, and U.S. Provisional Patent Application No. 63 / 423,468, filed November 7, 2022, the contents of which are incorporated by reference in their entireties herein.

[0002] The present application is directed to sheaths for use in catheter-based techniques for repairing and / or replacing heart valves, as well as for delivering implants, such as prosthetic valves, to the heart via a patient's vasculature. [Background technology]

[0003] Intravascular delivery catheter assemblies are used to implant prosthetic devices, such as prosthetic valves, at locations inside the body that are not easily 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 treatment sites using minimally invasive surgical techniques. Percutaneous interventional medical procedures utilize the body's large blood vessels to reach the target location rather than surgically retracting the target site. There are many types of disease conditions that can be treated via interventional methods, including coronary artery occlusion, valve replacement (TAVR), and cerebral aneurysms. These techniques include using wires, catheters, balloons, electrodes, and other thin devices to travel lengths of blood vessels from an access site to a target site. The devices have a proximal end that the clinician controls outside the body and a distal end inside the body that is involved in the treatment of the disease state. Percutaneous interventional procedures offer several advantages over open surgical techniques. First, they require smaller incisions, which also reduce bruising and bleeding, as well as the risk of infection. The procedure is also less traumatic to tissue, thus reducing recovery time. Finally, interventional techniques can usually be performed more quickly, and fewer clinicians are involved in the procedure, reducing overall costs. In some cases, the need for anesthesia is also eliminated, further speeding up the recovery process and reducing risk.

[0004] 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 sequentially removed from the access site. For example, a guidewire is used to track to the correct location within the body. A balloon may then be used to dilate a narrowed section of blood vessel. Finally, an implant may be delivered to the target site. Because catheters are frequently inserted and removed, introducer sheaths are used to protect local anatomy and simplify the procedure.

[0005] An introducer sheath can be used to safely introduce a delivery device into a patient's vasculature (e.g., the femoral artery). The introducer sheath is a conduit that seals onto the blood vessel at the access site to reduce bleeding and trauma to the vessel caused by rough edges of the catheter. The introducer sheath generally has an elongated sleeve that is inserted into the vasculature and a housing that includes one or more sealing valves that can place the delivery device in fluid communication with the vasculature with minimal blood loss. Once the introducer sheath is positioned within the vasculature, the shaft of the delivery device is advanced through the sheath into the vasculature, carrying the prosthetic device. The expandable introducer sheath allows the blood vessel to expand, which is effected by the prosthetic device passing through it. Expandable introducer sheaths are disclosed in 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. Application No. 14 / 880,109, entitled "Expandable Sheath," U.S. 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. Application No. 15 / 997,587, entitled "Expandable Sheath for Introducing an Endovascular Delivery Device into a Body," and U.S. Application No. 16 / 378,417, entitled "Expandable Sheath," the disclosures of which are incorporated herein by reference.

[0006] Traditional methods of accessing blood vessels, such as the femoral artery, prior to introducing a delivery system include dilating the blood vessel using multiple dilators or sheaths of progressively increasing diameter. Thus, delivery and / or removal of prosthetic devices and other materials to or from a patient still poses significant risks to the patient. Repeated insertions and vessel dilations can increase the amount of time the procedure takes, as well as the risk of damage to the blood vessel. Furthermore, accessing the blood vessel remains a challenge due to the relatively large profile of the delivery system, which can cause longitudinal and radial lacerations of the blood vessel during insertion. The delivery system can additionally ablate calcified plaque within the blood vessel, resulting in an additional risk of thrombus caused by the ablated plaque. Furthermore, some procedures, such as, for example, a transseptal approach for mitral valve replacement / repair, require prolonged dilation of the heart tissue incision and curving / bending of the sheath to access the treatment site, extending procedure time and recovery and increasing the risk of trauma to the blood vessel and heart tissue.

[0007] Thus, a need remains for further improved expandable introducer sheaths for endovascular systems used to implant valves and other prosthetic devices. Summary of the Invention

[0008] The present examples of expandable sheaths can minimize trauma to the vessel by allowing a temporary expansion of a portion of the introducer sheath to accommodate the delivery system, followed by a return to the original diameter once the delivery system has passed. Some examples can include a sheath having a smaller profile than that of prior art introducer sheaths. Additionally, some examples can reduce procedure time and reduce the risk of longitudinal or radial vessel tearing or plaque avulsion because only one sheath is required, rather than several different sized sheaths. The present examples of expandable sheaths can require only a single vessel insertion, as opposed to multiple insertions required for vessel expansion. The present examples of expandable sheaths can include a movable outer seal or gasket to provide hemostasis by contracting the sheath and preventing blood from the patient from penetrating between various layers of the sheath, for example, the inner layer of the sheath and the outer elastomeric jacket.

[0009] One exemplary gasket includes a gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between proximal and distal ends of the gasket body, the inner surface defining a lumen, the gasket being elastically movable between an unexpanded diameter and an expanded diameter, the gasket being configured to expand from the unexpanded diameter toward the expanded diameter when the gasket is biased toward the unexpanded diameter and the gasket body is subjected to a threshold radial force against the inner surface of the gasket body.

[0010] In some cases, the proximal end defines a proximal inner diameter and the distal end defines a distal inner diameter, the proximal inner diameter and the distal inner diameter each being sized and configured to receive an introducer sheath within the lumen of the gasket.

[0011] In some cases, the proximal end defines a proximal outer diameter and the distal end defines a distal outer diameter, the proximal outer diameter being larger than the distal outer diameter.

[0012] In some cases, the distal outer diameter is sized and configured to be received at least partially within the inner diameter of the vascular closure device.

[0013] In some cases, the gasket includes a flared surface at the proximal end adjacent the proximal outer diameter.

[0014] In some examples, the flared surface is sized and configured to provide a gripping surface.

[0015] In some cases, the gasket includes a tapered surface at a distal end adjacent the distal outer diameter.

[0016] In some cases, the tapered surface is sized and configured to be located at least partially within a blood vessel.

[0017] In some cases, the gasket is constructed from an elastomeric material (eg, silicone rubber, nitrile rubber, neoprene, santoprene).

[0018] In some examples, the gasket is constructed from a material having a durometer in the range of 40A to 60A.

[0019] In some cases, the unexpanded inner diameter ranges from 0.210 inches to 0.315 inches and the expanded diameter ranges from 0.286 inches to 0.430 inches.

[0020] Another example of an introducer sheath system includes a gasket as described above and a sheath for delivering a medical device. The sheath includes a sheath body defining a central lumen extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the body and a larger diameter portion adjacent a proximal end of the body, the body including an inner layer defining at least a portion of the central lumen of the sheath and an outer layer extending at least partially around the inner layer. The sheath is disposed within the lumen of the gasket. The gasket exerts a radially inward force on the outer layer such that the outer layer is sealed against the inner layer adjacent a location of the gasket preventing fluid flow therebetween, the gasket being longitudinally movable along an outer surface of the sheath from the larger diameter portion of the sheath to the distal end of the sheath.

[0021] In some examples, the sheath further includes a folded portion configured to move between a folded configuration and a less folded configuration during expansion of the sheath.

[0022] In some examples, the inner layer includes a folded portion configured to move between a folded configuration and a less folded configuration during local expansion of the sheath.

[0023] In some examples, the folded portion includes a first folded region and a second folded region and an overlap portion extending between the first folded region and the second folded region, wherein the first folded region is configured to move proximate the second folded region to shorten the overlap portion at a local axial location during application of a radially outward force by passage of a medical device, the shortening of the overlap portion corresponding to a localized expansion of the lumen.

[0024] In some examples, the first folded region is configured to move away from the second folded region to lengthen the overlap at a local axial location after the outward radial force is removed, the lengthening of the overlap corresponding to a localized constriction of the lumen.

[0025] In some examples, the first folded region and the second folded region are circumferentially spaced apart from one another, with an overlap extending circumferentially between the first and second folded regions.

[0026] In some examples, the inner layer defines a circumferentially continuous layer with the overlapping portion spaced radially from an outer surface of the non-overlapping portion of the inner layer, and the outer layer defines a discontinuous outer layer including a base portion that radially spaces the overlapping portion away from the outer surface of the non-overlapping portion.

[0027] In some cases, the proximal end of the gasket defines a proximal inner diameter and the distal end of the gasket defines a distal inner diameter, the proximal and distal inner diameters each being sized and configured to receive a sheath within the lumen of the gasket.

[0028] In some cases, the proximal end defines a proximal outer diameter and the distal end defines a distal outer diameter, the proximal outer diameter being larger than the distal outer diameter.

[0029] In some cases, the distal outer diameter is sized and configured to be received at least partially within the inner lumen of the vascular closure device.

[0030] In some cases, the proximal outer diameter defines a flared surface.

[0031] In some examples, the flared surface is sized and configured to provide a gripping surface.

[0032] In some cases, the distal outer diameter defines a tapered surface.

[0033] In some cases, the taper is sized and configured to be located at least partially within a blood vessel.

[0034] In a further example, the introducer sheath system includes a sheath for introducing a prosthetic device including an inner layer and an outer layer. At least a portion of the sheath may be designed or configured to locally expand from a first diameter to a second diameter when the prosthetic device is pushed through the lumen of the sheath, and then at least partially return to the first diameter when the prosthetic device is passed. Some examples may additionally include an elastic outer cover disposed around the outer layer. The inner layer may include polytetrafluoroethylene (PTFE), polyimide, polyetheretherketone (PEEK), polyurethane, nylon, polyethylene, polyamide, or combinations thereof. The outer layer may include PTFE, polyimide, PEEK, polyurethane, nylon, polyethylene, polypropylene, polyamide, polyether block amide, polyether block ester copolymer, thermoset silicone, latex, polyisoprene rubber, high density polyethylene (HDPE), Tecoflex™, or combinations thereof. In one example, the inner layer may include PTFE and the outer layer may include a combination of HDPE and Tecoflex™. If present, the elastic outer cover may comprise any suitable material, such as any suitable heat shrink material. Examples include Pebax, polyurethane, silicone, and / or polyisoprene.

[0035] Disclosed examples of sheaths include a proximal end and a distal end opposed to one another. Some examples may include a hemostatic valve at or near the proximal end of the sheath. In some examples, the outer diameter of the sheath gradually decreases from the proximal end of the sheath to the distal end of the sheath. In other examples, the outer diameter of the sheath is substantially constant along at least a majority of the length of the sheath.

[0036] One example of a sheath for introducing a prosthetic device into a body can include a continuous inner layer defining a lumen therethrough, the inner layer having a folded portion and a discontinuous outer layer having an overlapping portion and a base portion. In some examples, the inner layer can have at least two folded portions. The outer layer can be configured such that the overlapping portion overlaps the base portion, with at least a portion of the folded portion of the inner tubular layer being positioned between the overlapping portion and the base portion. At least a portion of the sheath is configured to expand to accommodate the prosthetic device.

[0037] In some examples, at least a portion of the sheath is configured such that each of a plurality of segments of the sheath locally expands, one at a time, from a rest configuration having a first diameter to an expanded configuration having a second diameter greater than the first diameter to facilitate passage of a prosthetic device through the lumen of the inner layer. Each segment may have a length defined along a longitudinal axis of the sheath, and each segment of the sheath may be configured to at least partially return to the first diameter upon passage of a prosthetic device. In some examples, when each segment of the sheath is in the expanded configuration, a length of the folded portion corresponding to the length of the segment at least partially unfolds (e.g., by separating and / or straightening). A length of the overlapping portion corresponding to the length of the segment may be configured to move relative to the base portion when each segment of the sheath expands from the rest configuration to the expanded configuration.

[0038] An exemplary method of sealing a sheath includes providing a radially expandable gasket defining a lumen; providing a sheath including a sheath body defining a central lumen extending therethrough, a smaller diameter portion, and a larger diameter portion proximal to the smaller diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximal to the larger diameter portion of the sheath, thereby elastically expanding the diameter of the gasket lumen; inserting the sheath into a patient's blood vessel; inserting a medical device through the central lumen of the sheath; and advancing the gasket distally to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting the diameter of the gasket lumen, thereby sealing the sheath and preventing blood flow from the patient proximal to the location of the gasket.

[0039] In some examples, the sheath includes a sheath body defining a central lumen of the sheath and extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the body and a larger diameter portion adjacent a proximal end of the body, the body including an inner layer defining at least a portion of the central lumen of the sheath and an outer layer extending at least partially around the inner layer.

[0040] In some examples, sealing the sheath includes sealing a gap between an inner layer and an outer layer of the sheath.

[0041] In some examples, the method further includes inserting the gasket at least partially into the patient's blood vessel.

[0042] In some examples, the method further includes advancing a gasket proximally over the larger diameter portion of the sheath, advancing a medical device proximally through the lumen of the sheath, and removing the sheath from the patient's blood vessel.

[0043] A further method of sealing a sheath includes providing a radially expandable gasket defining a lumen; providing a sheath including a sheath body defining a central lumen extending therethrough, a smaller diameter portion, and a larger diameter portion proximal to the smaller diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximal to the larger diameter portion of the sheath, thereby elastically expanding the diameter of the gasket lumen; inserting a medical device through the central lumen of the sheath; and advancing the gasket distally to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting the diameter of the gasket lumen, thereby sealing the sheath and preventing blood flow from the patient proximal to the location of the gasket.

[0044] Another exemplary gasket includes a housing and a gasket body provided at least partially within the housing, the gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between proximal and distal ends of the gasket body, the inner surface defining a lumen, the lumen being elastically movable between an unexpanded diameter and an expanded diameter, the lumen being biased toward the unexpanded diameter, and the lumen being configured to expand from the unexpanded diameter toward the expanded diameter upon exposure to a threshold radial force against the inner surface of the gasket body.

[0045] In some cases, the proximal end defines a proximal inner diameter and the distal end defines a distal inner diameter, the proximal inner diameter and the distal inner diameter each being sized and configured to receive an introducer sheath within the lumen of the gasket.

[0046] In some cases, the gasket is constructed from an elastomeric material (eg, silicone rubber, nitrile rubber, polyisoprene, neoprene, santoprene).

[0047] In some examples, the gasket is constructed from a material having a durometer in the range of 40A to 60A.

[0048] In some cases, the unexpanded inner diameter ranges from 0.100 inches to 0.450 inches (eg, 0.210 inches to 0.315 inches) and the expanded diameter ranges from 0.286 inches to 0.430 inches.

[0049] In some examples, the housing includes an opening for receiving the gasket body such that the housing surrounds an outer surface of the gasket body.

[0050] In some examples, the gasket body is disposed within a housing such that the housing prevents radial expansion of an outer surface of the gasket body.

[0051] In some examples, at least a portion of the proximal and distal end faces of the gasket body are disposed within the housing.

[0052] In some cases, the housing is constructed from a material that is stiffer than the gasket body (eg, polycarbonate).

[0053] In some cases, the housing includes an attachment mechanism (eg, to allow the gasket to be sutured in place at the patient's skin level).

[0054] In some examples, the mounting mechanism includes a mounting opening extending through the housing.

[0055] In some examples, the mounting opening is provided on an arm that extends beyond an outer surface of the housing.

[0056] In some cases, the periphery of the housing defines an overall diameter that is greater than the expanded diameter of the introducer sheath (eg, the periphery of the housing has a diameter in the range of 0.430 inches to 0.700 inches).

[0057] In some cases, a distal outer periphery of the housing is sized and configured to be received at least partially within an inner diameter of the vascular closure device.

[0058] In some examples, the exterior surface of the housing is sized and configured to provide a gripping surface (eg, a flared or textured exterior surface).

[0059] In some examples, at least a portion of the distal end surface of the housing and / or the distal end surface of the gasket body are configured to be at least partially located within or adjacent to a blood vessel and / or other patient anatomical structure (e.g., the housing may include a tapered surface at the distal end).

[0060] Another example of an introducer sheath system includes a gasket, a housing, and a sheath body. The gasket includes a housing and a gasket body provided at least partially within the housing, the gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between a proximal end and a distal end of the gasket body, the inner surface defining an inner lumen, the inner lumen being resiliently movable between an unexpanded diameter and an expanded diameter, the inner lumen being biased toward the unexpanded diameter, and the inner lumen being configured to expand from the unexpanded diameter toward the expanded diameter upon experiencing a threshold radial force against the inner surface of the gasket body. A sheath for delivering a medical device is provided. The sheath includes a sheath body defining a central lumen extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the sheath body and a larger diameter portion adjacent a proximal end of the sheath body, the sheath body including an inner layer defining at least a portion of the central lumen of the sheath and an outer layer extending at least partially around the inner layer, the sheath is disposed within the lumen of the gasket and the gasket exerts a radially inward force on the outer layer such that the outer layer is sealed against the inner layer adjacent a location of the gasket preventing fluid flow therebetween, the gasket being longitudinally movable along an outer surface of the sheath from the larger diameter portion of the sheath to the distal end of the sheath.

[0061] In some examples, the sheath further includes a folded portion configured to move between a folded configuration and a less folded configuration during expansion of the sheath.

[0062] In some examples, the inner layer includes a folded portion configured to move between a folded configuration and a less folded configuration during local expansion of the sheath.

[0063] In some examples, the folded portion comprises a first folded region and a second folded region and an overlapping portion extending between the first and second folded regions, wherein the first folded region is configured to move proximate the second folded region to shorten the overlapping portion at a local axial location during application of a radially outward force by passage of a medical device, the shortening of the overlapping portion corresponding to localized expansion of the lumen.

[0064] In some examples, the first folded region is configured to move away from the second folded region to lengthen the overlap at a local axial location after the outward radial force is removed, the lengthening of the overlap corresponding to a localized constriction of the lumen.

[0065] In some examples, the first folded region and the second folded region are circumferentially spaced apart from one another, with an overlap extending circumferentially between the first and second folded regions.

[0066] In some examples, the inner layer defines a circumferentially continuous layer with the overlapping portion spaced radially from an outer surface of the non-overlapping portion of the inner layer, and the outer layer defines a discontinuous outer layer including a base portion that radially spaces the overlapping portion away from the outer surface of the non-overlapping portion.

[0067] In some examples, the inner layer defines a circumferentially continuous layer with the overlapping portion radially spaced from an outer surface of the non-overlapping portion of the inner layer, and discontinuous intermediate and outer layers including a base portion radially spaced from the outer surface of the non-overlapping portion define a resilient outer jacket extending over both the inner and intermediate layers.

[0068] In some examples, the proximal end of the gasket defines a proximal inner diameter and the distal end of the gasket defines a distal inner diameter, the proximal and distal inner diameters each being sized and configured to receive a sheath within the lumen of the gasket.

[0069] In some cases, a distal periphery of the housing is sized and configured to be received at least partially within an inner lumen of the vascular closure device.

[0070] In some examples, the exterior surface of the housing is sized and configured to provide a gripping surface (eg, a flared or textured exterior surface).

[0071] In some examples, at least a portion of the distal end surface of the housing and / or the distal end surface of the gasket body are configured to be positioned at least partially within a blood vessel (e.g., the housing and / or the gasket body may include a tapered surface at the distal end).

[0072] A further method of sealing a sheath includes providing a radially expandable gasket defining a lumen; providing a sheath including a sheath body defining a central lumen extending therethrough, a smaller diameter portion, and a larger diameter portion proximal to the smaller diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximal to the larger diameter portion of the sheath, thereby elastically expanding the diameter of the gasket lumen; inserting the sheath into the patient's blood vessel; inserting a medical device through the central lumen of the sheath; advancing the gasket distally to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting the diameter of the gasket lumen, thereby sealing the sheath and preventing blood flow from the patient proximal to the location of the gasket; and securing the gasket to the patient.

[0073] In some examples, the method further includes a sheath including a sheath body defining a central lumen of the sheath and extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the body and a larger diameter portion adjacent a proximal end of the body, the body comprising an inner layer defining at least a portion of the central lumen of the sheath and an outer layer extending at least partially around the inner layer.

[0074] In some examples, the method further includes, where sealing the sheath includes sealing a gap between the inner layer and the outer layer of the sheath.

[0075] In some examples, the method further includes the gasket including an attachment mechanism, the gasket being secured to the patient with the attachment mechanism.

[0076] In some examples, the method includes a method in which the attachment mechanism includes an attachment opening, and securing the gasket to the patient includes suturing the gasket to the patient at the patient's skin level by passing a suture through the attachment opening in the gasket and into / through the patient (e.g., into / through the patient).

[0077] In some examples, the method further includes inserting the gasket at least partially into the patient's blood vessel.

[0078] In some examples, the method further includes removing the gasket from the patient, advancing the gasket proximally, advancing a medical device proximally through the lumen of the sheath, and removing the sheath from the patient's blood vessel.

[0079] Another method of sealing the sheath includes providing a radially expandable gasket defining a lumen; providing a sheath including a sheath body defining a central lumen extending therethrough, a smaller diameter portion, and a larger diameter portion proximal to the smaller diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximal to the larger diameter portion of the sheath, thereby elastically expanding the diameter of the gasket lumen; inserting a medical device through the central lumen of the sheath; advancing the gasket distally to a distal position such that the gasket is outside the patient's blood vessel, thereby elastically contracting the diameter of the gasket lumen, thereby sealing the sheath and preventing blood flow from the patient proximal to the location of the gasket; and releasably coupling the gasket to the patient.

[0080] The foregoing and other features and advantages of the present invention will become more apparent from the following detailed description which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0081] [Figure 1] FIG. 1 is an elevational view of an expandable sheath together with an intravascular delivery device for implanting a prosthetic implant. [Diagram 2] FIG. 2 is an elevational view of an expandable sheath including an introducer locking hub, a sheath locking sleeve, and an introducer. [Diagram 3] FIG. 3 is an elevational view of the expandable sheath of FIG. 2 together with an intravascular delivery device for implanting the prosthetic implant. [Figure 4] 4 is a cross-sectional view of the distal end of the sheath of FIG. 3 taken along line AA of FIG. [Diagram 5] 5 is a cross-sectional view of the proximal section of the sheath of FIG. 35 taken along line BB of FIG. [Figure 6] 6 is a cross-sectional view of the sheath of FIG. 3 in a resting (unexpanded) configuration taken along line CC of FIG. [Figure 7] FIG. 7 is a cross-sectional view of the sheath of FIG. 6 in an expanded configuration. [Figure 8] 8 is a cross-sectional view of the sheath of FIG. 3 in a resting (unexpanded) configuration including an outer jacket taken along line AA of FIG. [Figure 9] 9 is a cross-sectional view of the sheath of FIG. 8 in a resting (unexpanded) configuration taken along line CC of FIG. [Figure 10] FIG. 10 is a cross-sectional view of the sheath of FIG. 9 in an expanded configuration. [Figure 11] FIG. 11 is a cross-sectional view of the sheath of FIG. 9 in a resting (unexpanded) configuration, including a lubricant between the outer layer and the outer jacket. [Figure 12] FIG. 12 is a cross-sectional view of the sheath of FIG. 9 in a resting (unexpanded) configuration, including a lubricant and a bonding strip. [Figure 13] FIG. 13 is a bottom perspective view of the sheath of FIG. [Figure 14] FIG. 14 is a bottom perspective view of the sheath of FIG. [Figure 15] FIG. 15 is a top perspective view of the sheath of FIG. [Figure 16] 16 is a cross-sectional view of the sheath of FIG. 18 in a resting (unexpanded) configuration taken along line CC of FIG. [Figure 17] FIG. 17 is an elevational view of another example expandable outer jacket. [Figure 18] 18 is a cross-sectional view of the expandable sheath of FIG. 17 taken along section line AA of FIG. [Figure 19] 19 is a cross-sectional view of the expandable outer jacket in a resting (unexpanded) configuration taken along section line BB of FIG. [Figure 20] FIG. 20 is a partial view of the outer jacket of FIG. [Figure 21] 21 is a cross-sectional view of another exemplary outer jacket in a resting (unexpanded) configuration including a single reinforcing member taken along section line BB of FIG. 17. [Figure 22] FIG. 22 is a schematic diagram of a sheath extending within a patient's vasculature. [Diagram 23] FIG. 23 is a schematic illustration of sheath ballooning in response to blood loss between sheath layers. [Figure 24] FIG. 24 is an elevational view of a sheath including a gasket disposed about the sheath in a proximal position. [Diagram 25] FIG. 25 is an elevational view of a sheath including a gasket disposed about the sheath in a distal position. [Figure 26] FIG. 26 is a schematic diagram of an elevational view of a sheath including a gasket having a uniform outer diameter at the proximal and distal positions. [Figure 27] FIG. 27 is a schematic diagram of an elevational view of a sheath including a gasket having a tapered outer diameter at the proximal and distal positions. [Figure 28] FIG. 28 is a perspective view of the gasket and housing. [Figure 29] 29 is a top view of the gasket and housing of FIG. 28. FIG. [Diagram 30] FIG. 30 is a cross-sectional view of the gasket of FIG. [Diagram 31] FIG. 31 is an elevational view of a sheath including the gasket of FIG. [Diagram 32] FIG. 32 is a partial cross-sectional elevational view of the sheath of FIG. 31 positioned within a patient's anatomy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] The following description of specific examples of the inventive concept should not be used to limit the scope of the claims. Other examples, features, aspects, embodiments, and advantages will become apparent to those skilled in the art from the following description. As will be appreciated, the apparatus and / or method may have other different and obvious aspects, all without departing from the spirit of the inventive concept. Accordingly, the drawings and description should be regarded as illustrative in nature, and not restrictive.

[0083] For purposes of this specification, certain aspects, advantages, and novel features of the disclosed embodiments are described herein. The described methods, systems, and devices should not be construed as limiting in any way. Instead, the disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments, both alone and in various combinations and subcombinations with each other. The disclosed methods, systems, and devices are not limited to any specific aspects, features, or combinations thereof, nor do the disclosed methods, systems, and devices require that any one or more specific advantages exist or problems be solved.

[0084] It is understood that features, integers, properties, compounds, chemical moieties, or groups described in conjunction with a particular embodiment or example of the present disclosure are applicable to any other embodiment or example described herein, unless incompatible therewith. All of the features disclosed herein (including any of the 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 in which at least some of such features and / or steps are mutually exclusive. The present disclosure is not limited to the details of any of the foregoing embodiments. The present disclosure extends to any novel, or any novel combination, of features disclosed herein (including any of the accompanying claims, abstract, and drawings), or any novel, or any novel combination of steps of any method or process similarly disclosed.

[0085] It should be understood that any patent, publication, or other disclosure material that is said to be incorporated by reference herein, in whole or in part, is incorporated herein, but only to the extent that the incorporated material does not contradict existing definitions, statements, or other disclosure material set forth in this disclosure. Therefore, and to the extent necessary, the present disclosure as expressly 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 that contradicts existing definitions, statements, or other disclosure material set forth herein, is incorporated only to the extent that no conflict arises between the incorporated material and the existing disclosure material.

[0086] As used in this application and the claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Additionally, the term "includes" means "comprises." Furthermore, the terms "coupled" and "associated" generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or connected and do not exclude the presence of intermediate elements between the coupled or associated items.

[0087] As used herein, the terms "proximal" and "distal" refer to the regions of a sheath, catheter, or delivery assembly. "Proximal" means the region closest to the handle of the device, while "distal" means the region furthest from the handle of the device.

[0088] As used herein, "axially" or "axial" refers to a direction along the longitudinal axis of the sheath.

[0089] Throughout the description and claims of this specification, the word "comprise" and variations of that word, such as "comprising" and "comprises," mean "including, but not limited to," and are not intended to exclude, for example, other additives, components, integers, or steps. "Exemplary" means "an example of," and is not intended to suggest a preferred or ideal embodiment. "Etc." is not used in a limiting sense, but rather for illustrative purposes.

[0090] The disclosed examples of expandable sheaths can minimize trauma to the vessel by allowing temporary expansion of a portion of the introducer sheath to accommodate the delivery system, followed by return to the original diameter once the device has passed. Some examples can include a sheath with a smaller profile (e.g., smaller diameter in the resting configuration) than that of prior art introducer sheaths. Additionally, the current examples can reduce procedure time and reduce the risk of longitudinal or radial vessel tearing or plaque avulsion, since only one sheath is required, rather than several different sizes of sheaths. The present examples of expandable sheaths can avoid the need for multiple insertions for vessel expansion. Such expandable sheaths can be useful for many types of minimally invasive surgical procedures, such as any surgical procedure that requires the introduction of a device into a subject's vessel. For example, the sheath may be used to introduce other types of delivery devices for placing various types of intraluminal devices (e.g., stents, prosthetic heart valves, stented grafts, etc.) within many types of vascular and non-vascular body lumens (e.g., veins, arteries, esophagus, biliary system ducts, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.).

[0091] The disclosed embodiments of the expandable sheath can minimize trauma to the vessel by allowing for temporary expansion of a portion of the introducer sheath to accommodate the delivery system, followed by return to the original diameter once the device has passed. Additionally, the current embodiments can reduce procedure time and reduce the risk of longitudinal or radial vessel tears or plaque avulsion because only one sheath is required rather than several different sized sheaths. The present expandable sheath embodiments can avoid the need for multiple insertions to expand the vessel.

[0092] Disclosed herein is an elongated introducer sheath that is 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. Examples of such implantable heart valves are described in U.S. Pat. Nos. 5,411,552 and 9,393,110, both of which are incorporated herein by reference. The expandable introducer sheath disclosed herein may also be used to deliver other types of implantable medical devices, such as self-expanding and mechanically expanding implantable heart valves, stents or filters. Beyond transcatheter heart valves, the introducer sheath system may be useful in other types of minimally invasive surgical procedures, such as surgical procedures that require the introduction of a device into a subject's blood vessel. For example, the introducer sheath system may be used to introduce other types of delivery devices for placement of various types of intraluminal devices (e.g., stents, stent grafts, balloon catheters for angioplasty procedures, etc.) into many types of vascular and non-vascular lumens (e.g., veins, arteries, esophagus, biliary ducts, intestines, urethra, fallopian tubes, other endocrine or exocrine ducts, etc.). As used herein, the term "implantable" is broadly defined to mean anything, whether artificial or not, that is delivered to a site within the body. The diagnostic device may be, for example, an implantable diagnostic device.

[0093] FIG. 1 illustrates an exemplary sheath 100 for use with a representative delivery device 10 for delivering an implant 12, or other type of implantable, to a patient. The delivery device 10 can include a steerable guide catheter 14 (also referred to as a flex catheter), a balloon catheter 16 extending through the guide catheter 14, and a nasal catheter 18 extending through the balloon catheter 16. The guide catheter 14, balloon catheter 16, and nasal catheter 18 of the illustrated embodiment are adapted to slide longitudinally relative to one another to facilitate delivery and positioning of the implant 12 at an implantation site within the patient's body, as described in detail below. The sheath 100 is an elongated, expandable tube that can include a hemostatic valve at the proximal end of the sheath to prevent blood leakage.

[0094] In use, the sheath 100 and introducer 6 are inserted through the patient's skin and into a blood vessel (e.g., the femoral or iliac artery) such that the distal end of the sheath 100 is inserted into the vessel. Figure 2 shows the sheath 100 of Figure 1 including a sheath locking system 15 that prevents axial and rotational movement of the introducer 6 relative to the sheath 100. The sheath locking system 15 secures the introducer 6 relative to the sheath 100 during insertion without requiring a physician or technician to hold the introducer 6 and sheath 100 in a fixed position at the distal end. The sheath locking system 15 includes a locking sleeve 28 coupled to the sheath 100 via a sheath hub 20 and an introducer locking hub 30, and the introducer 6. The locking sleeve 28 engages the introducer locking hub 30 and is movable between locked and unlocked positions, thereby fixing the position of the introducer 6 and sheath 100 and preventing movement therebetween during insertion. The sheath locking system 15 prevents the introducer 6 from separating from the sheath 100 and prevents the formation of gaps that could cause patient abrasions and unintended fluid flow between the introducer 6 and sheath 100 during insertion. Exemplary locking systems for use with expandable delivery sheaths are disclosed, for example, in PCT / US2021 / 050006, filed September 13, 2021 (corresponding to U.S. Provisional Patent Application No. 63 / 077,899, filed September 13, 2020), the disclosure of which is incorporated herein by reference in its entirety.

[0095] As described in more detail below, once the sheath 100 / introducer 6 is positioned at the delivery site, the introducer 6 is removed from the sheath and the implant 12 is delivered through the sheath 100 and implanted within the patient. Figure 3 shows the sheath of Figures 1 and 2 with the introducer 6 removed and the implant 12 / balloon catheter 16 passed therethrough.

[0096] Exemplary expandable sheaths are also disclosed in U.S. Patent Application No. 12 / 249,867, filed October 10, 2008 (now U.S. Patent No. 8,690,936), U.S. Patent Application No. 13 / 312,739, filed December 6, 2011 (now U.S. Patent No. 8,790,387), U.S. Patent Application No. 14 / 248,120, filed April 8, 2014 (now U.S. Patent No. 9,301,840), U.S. Patent Application No. 14 / 324,894, filed July 7, 2014 (now U.S. Patent No. 9,301,841), U.S. Patent Application No. 15 / 057,953, filed March 1, 2016 (now U.S. Patent No. 9,987,134), No. 15 / 997,587, filed June 4, 2018, U.S. Patent Application No. 16 / 149,953, filed October 2, 2018 (now U.S. Patent No. 10,524,905), U.S. Patent Application No. 16 / 149,956, filed October 2, 2018 (now U.S. Patent No. 10,517,720), U.S. Patent Application No. 16 / 149,960, filed October 2, 2018 (now U.S. Patent No. 10,524,906), and U.S. Patent Application No. 16 / 149,969, filed October 2, 2018 (now U.S. Patent No. 10,524,907), the disclosures of which are incorporated herein by reference.

[0097] The sheath 100 may be inserted into a patient's blood vessel by passing through the patient's skin such that a soft tip portion at the distal end of the sheath 100 is inserted into the blood vessel. The sheath 100 may also include a proximal flared end portion to facilitate mating with the sheath hub 20 and the catheter described above (e.g., the proximal flared end portion may provide a compression fit over the housing tip and / or may be secured to the sheath hub 20 via a sheath hub cap 22 or other fastening device or by joining the proximal end of the sheath to the sheath hub 20). The sheath hub 20 provides a housing for the necessary valve / seal assembly and an access point for a secondary lumen (e.g., a fluid lumen) that is in fluid communication with the central lumen of the sheath hub 20. The valve / seal forms a seal around the outer surface of the delivery device when inserted through the sheath hub 20. The delivery device may be inserted into and through the sheath 100 to allow the prosthetic device to be advanced through the patient's vasculature and implanted within the patient.

[0098] FIG. 4 shows a cross-sectional view of the sheath 100 taken near the distal end of the sheath 100 taken along section line AA (FIG. 3). The sheath 100 may include multiple layers. For example, the sheath 100 may include an inner layer 108 and an outer layer 110 disposed about the inner layer 108. The sheath 100 may include an outer jacket 140 extending over the outer layer 110. The inner layer 108 may define a lumen through which a delivery device may advance within a patient's vasculature to deliver, remove, repair, and / or replace a prosthetic device moving in a direction along the longitudinal axis X. As the prosthetic device passes through the sheath 100, the sheath 100 locally expands from a first resting diameter to a second expanded diameter to accommodate the prosthetic device. After the prosthetic device passes through a particular location of the sheath 100, each successive expanded portion or segment of the sheath 100 at least partially returns to a smaller resting diameter. In this manner, the sheath 100 may be considered self-expanding, in that it does not require the use of balloons, dilators, and / or obturators to expand.

[0099] The inner layer 108 and the outer layer 110 can include any suitable material. Suitable materials for the inner layer 108 include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyether block amide (e.g., PEBAX), and / or combinations thereof. In one specific example, the inner layer 108 can include a lubricious, low friction, or hydrophilic material, such as PTFE. Such low coefficient of friction materials can facilitate the passage of a prosthetic device through the lumen defined by the inner layer 108. In some examples, the inner layer 108 can have a coefficient of friction of less than about 0.1. Some examples of the sheath 100 can include a lubricious liner on the inner surface of the inner layer 108. Examples of suitable lubricious liners include materials that can further reduce the coefficient of friction of the inner layer 108, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for the lubricious liner also include other materials that desirably have a coefficient of friction of 0.1 or less.

[0100] Suitable materials for the outer layer 110 include nylon, polyethylene, PEBAX, HDPE, polyurethane (e.g., Tecoflex™), and other medical grade materials. In one example, the outer layer 110 can include 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 108 and the outer layer 110 and can be present only along a portion of the inner surface of the outer layer 110. Other suitable materials for the inner and outer layers are also disclosed in U.S. Patent Application Publication No. 2010 / 0094392, which is incorporated herein by reference.

[0101] In addition, some examples of the sheath 100 may include an exterior hydrophilic coating on the outer surface of the outer layer 110. Such a hydrophilic coating may facilitate insertion of the sheath 100 into a patient's blood vessel. Examples of suitable hydrophilic coatings include Harmony™ advanced lubricity coatings available from SurModics, Inc. of Eden Prairie, Minnesota, and other advanced hydrophilic coatings. DSM Medical Coatings (available from Koninklijke DSM NV, Heerlen, The Netherlands), as well as other hydrophilic coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride), are also suitable for use with the sheath 100.

[0102] The soft tip portion of the sheath 100, in some examples, can include low density polyethylene (LDPE) and can be configured to minimize trauma or damage to the patient's blood vessels as the sheath is navigated through the vasculature. For example, in some aspects, the soft tip portion can be slightly tapered to facilitate passage through the blood vessels. The soft tip portion can be secured to the distal end of the sheath 100, such as by thermally bonding the soft tip portion to the inner and outer layers of the sheath 100. Such a soft tip portion can comprise a lower hardness than other portions of the sheath 100. In some aspects, the soft tip can have a Shore hardness of about 25D to about 40D. The tip portion is radially expandable and configured to allow a prosthetic device to pass through the distal opening of the sheath 100. For example, the tip portion can be formed with a weakened portion, such as an axially extending score line or perforation line, that is configured to split and allow the tip portion to radially expand as a prosthetic device passes through the tip portion.

[0103] FIG. 4 illustrates a cross-sectional view of the sheath 100 taken near the distal end of the sheath 100 along section line AA (FIG. 3). As shown in FIG. 4, the sheath 100 can include at least one radiopaque filler or marker 112, such as a discontinuous or C-shaped band, positioned near the distal end 104 of the sheath 100. The marker 112 can be associated with the inner and / or outer layers 108, 110 of the sheath 100. For example, as shown in FIG. 4, the marker 112 can be positioned between the inner layer 108 and the outer layer 110. In an alternative example, the marker 112 can be associated with an outer surface of the outer layer 110. In some examples, the marker 112 can be embedded or mixed within the inner layer 108 or the outer layer 110.

[0104] The C-band can function as a radiopaque marker or filler to allow visibility of the sheath 100 under fluoroscopy during use within a patient. The C-band / marker 112 can include any suitable radiopaque material, such as barium sulfite, bismuth trioxide, titanium dioxide, bismuth subcarbonate, platinum, iridium, and combinations thereof. In one specific example, the C-band / marker 112 can include 90% platinum and 10% iridium. In other examples, the marker 112 need not be a C-band. Other shapes, designs, and configurations are possible. For example, in some embodiments, the marker 112 can extend around the entire circumference of the sheath 100. In other examples, the marker 112 can include multiple small markers spaced around the circumference of the sheath 100.

[0105] 5 and 6 show additional cross-sectional views taken at different points along the sheath 100. FIG. 5 shows a cross-section of a segment of the sheath near the proximal end 106 of the sheath 100, as indicated by line BB in FIG. 3. The sheath 100 at this location can include an inner layer 108 and an outer layer 110. At this location near the proximal end of the sheath, the layers 108, 110 can be generally tubular without any slits or folded portions within the layers. In contrast, the layers 108, 110 at different locations along the sheath 100 (e.g., at the point indicated by line CC in FIG. 3) can have different configurations.

[0106] As shown in FIG. 6, the inner layer 108 may be arranged to form a substantially cylindrical lumen 116 therethrough. The inner layer 108 may include one or more folded portions 118. In the example shown in FIG. 6, the inner layer 108 is arranged to have one folded portion 118 that may be positioned on either side of the inner layer 108. The folded portion 118 includes a first fold (e.g., a longitudinally extending fold line) and a second fold and an overlap portion extending circumferentially therebetween (when the sheath is in an unexpanded configuration). As illustrated in FIG. 6, the folded portion 118 includes a radial overlap of at least two thicknesses of the inner layer 108. The inner layer 108 may be continuous in that there are no breaks, slits, or perforations in the inner layer 108. The outer layer 110 may be arranged in an overlapping manner such that the overlap portion 120 overlaps at least a portion of the folded portion 118 of the inner layer 108. 6, the overlapping portion 120 also overlaps with a base portion 122 of the outer layer 110. The base portion 122 may be positioned to underlie both the overlapping portion 120 of the outer layer 110 as well as the folded over portion 118 of the inner layer 108. Thus, the outer layer 110 may be discontinuous in that it includes slits or cuts to form the overlapping portion 120 and the base portion 122. In other words, a first edge 124 of the outer layer 110 is spaced from a second edge 126 of the outer layer 110 such that they do not form a continuous layer.

[0107] As shown in FIG. 6, the sheath 100 may also include a thin layer of bonding or adhesive material, also referred to as a tie layer or adhesive layer 128, positioned between the inner layer 108 and the outer layer 110. In one example, the adhesive material may include a polyurethane material, such as Tecoflex™ or etched PTFE tubing. The adhesive material may be positioned on at least a portion of the inner surface 130 of the outer layer 110 to provide adhesion between selected portions of the inner layer 108 and the outer layer 110. For example, the outer layer 110 may only include the adhesive layer 128 around a portion of the inner surface 130 that faces the lumen-forming portion of the inner layer 108. In other words, the adhesive layer 128 may be positioned so as not to contact the folded portion 118 of the inner layer 108 in some examples. In other examples, the adhesive layer 128 may be positioned in a different configuration as desired for a particular application. For example, as shown in FIG. 6, the adhesive layer 128 may be positioned along the entire inner surface 130 of the outer layer 110. In an alternative example, the adhesive layer may be applied to the outer surface of the inner layer 108 instead of the inner surface of the outer layer. The adhesive layer 128 may be applied to all or selected portions on the inner layer 108. For example, the adhesive layer 128 may be formed only on a portion of the inner layer facing the lumen-forming portion of the outer layer, and not on the folded portion. The configuration of FIG. 6 allows for radial expansion of the sheath 100 when an outwardly directed radial force is applied from the inside (e.g., by passing a medical device, such as a prosthetic heart valve, through the lumen 116). When a radial force is applied, the folded portion 118 may at least partially separate, straighten, and / or spread, and / or the overlapping portion 120 and the base portion 122 of the outer layer 110 may slide circumferentially relative to one another, thereby allowing the diameter of the lumen 116 to expand.

[0108] In this manner, the sheath 100 is configured to expand from the rest configuration (FIG. 6) to the expanded configuration shown in FIG. 7. In the expanded configuration, an annular gap 132 may be formed between the longitudinal edges of the overlapping portion 120 and the base portion 122 of the outer layer 110, as shown in FIG. 7. As the sheath 100 expands at a particular location (i.e., expands locally at the location of the passing prosthetic device), the overlapping portion 120 of the outer layer 110 may move circumferentially relative to the base portion 122 as the folded portion 118 of the inner layer 108 unfolds. This movement may be facilitated by the use of a low friction material for the inner layer 108, such as PTFE. Additionally, the folded portion 118 may at least partially separate and / or unfold to accommodate a medical device having a diameter larger than the diameter of the lumen 116 in the rest configuration. As shown in FIG. 7, in some instances, the folded portion of the inner layer 108 may fully unfold, such that the inner layer 108 forms a cylindrical tube at the expanded configuration.

[0109] The sheath 100 may be configured to locally expand at a specific location corresponding to the location of a medical device along the length of the lumen 116, and then locally contract as the medical device passes that specific location. Thus, as a medical device is introduced through the sheath, a bulge may be visible that progresses longitudinally along the length of the sheath, representing successive local expansions and contractions as the device progresses down the length of the sheath 100. In some examples, each segment of the sheath 100 may locally contract such that it resumes its original resting diameter of the lumen 116 after removal of any radially outward force. In some examples, each segment of the sheath 100 may locally contract such that it resumes its original resting diameter of the lumen 116, at least in part, after removal of any radially outward force.

[0110] The layers 108, 110 of the sheath 100 may be configured as shown in Figure 6 along at least a portion of the length of the sheath 100. In some examples, the layers 108, 110 may be configured as shown in Figure 6 along a length L (Figure 3) that extends from adjacent the soft tip portion 102 to a location closer to the proximal end 106 of the sheath 100 (e.g., adjacent to and / or including a strain relief portion, described below). In the present case, the sheath 100 is expandable and contractible only along a portion of the length of the sheath corresponding to length L (typically corresponding to the section of the sheath inserted into the narrowest section of the patient's vasculature).

[0111] As described above, the sheath 100 of FIG. 3 may encase an outer jacket 140 that extends over the outer layer 110. FIGS. 7 and 8 show additional cross-sectional views taken at different points along the sheath 100. Similar to FIG. 5, FIG. 7 shows a cross-section of a segment of the sheath near the proximal end of the sheath 100, as indicated by line BB in FIG. 3. The sheath 100 at this location may include an inner layer 108, an outer layer 110, an adhesive layer 128, and an outer jacket 140. At this location near the proximal end of the sheath, the layers 108, 110 and the outer jacket 140 may be generally tubular without any slits or folded portions within the layers. In contrast, the layers 108, 110 at different locations along the sheath 100 (e.g., at the point indicated by line CC in FIG. 3) may have different configurations, while the outer jacket 140 maintains a generally tubular shape without slits or folds.

[0112] As shown in FIG. 9 and described above with respect to FIG. 6, the inner layer 108 can be arranged to form a generally cylindrical lumen 116 extending therethrough. The inner layer 108 can include one or more folded portions 118. The outer layer 110 can be arranged in an overlapping manner such that the overlapping portion 120 overlaps at least a portion of the folded portion 118 of the inner layer 108 as well as a base portion 122 (positioned to underlie the folded portion 118 of the inner layer 108) when the sheath is unexpanded. The sheath 100 is configured to locally expand from an unexpanded configuration in which the lumen 116 has a first diameter to an expanded configuration in which the lumen 116 has a second diameter greater than the first diameter. The sheath 100 expands in response to an outwardly directed radial force exerted by a medical device against the inner layer 108 as it passes through the lumen 116. During expansion, the first crease / folded edge moves closer to the second crease / folded edge, shortening the folded portion 118. As shown in FIG. 10, in some instances, the folded portion 118 of the inner layer 108 can fully unfold, such that the inner layer 108 forms a cylindrical tube at the location of the expanded configuration. When the sheath is expanded, a portion of the inner layer 108 extends through an opening / gap provided in the outer layer 110, the opening being formed by the longitudinally extending edge of the overlapping portion 120 and the longitudinally extending edge of the base portion 122. Once the prosthetic device has passed, the sheath 100 then locally contracts back to at least partially unexpanded configuration.

[0113] As described above, the sheath 100 includes an inner layer 108. The inner layer 108 may be surface treated, such as by plasma etching, chemical etching, or other suitable methods of surface treatment. By treating the surface of the inner layer 108, the outer surface of the inner layer 108 may have areas with modified surface angles that may provide better adhesion between the inner layer 108 and the outer layer 110. As described above, the inner layer 108 may include polytetrafluoroethylene (PTFE), polyimide, polyetheretherketone (PEEK), polyurethane, nylon, polyethylene, polyamide, or combinations thereof. In the exemplary sheath 100, the inner layer 108 is comprised of an etched PTFE material. It is contemplated that the inner layer 108 may have a fully etched outer surface or a partially etched outer surface. When partially etched, the unetched portions of the outer surface of the inner layer 108 may extend longitudinally along the length of the inner layer 108 and / or circumferentially around the circumference of the inner layer 108. For example, desired unetched locations on the inner layer 108 may be masked or otherwise covered during the etching process to prevent etching at those locations. It is also contemplated that the entire exterior surface of the inner layer 108 may be etched and the etching removed at desired locations of the unetched surface.

[0114] In the exemplary sheath 100, non-etched portions are provided along the surfaces of the inner layer 108 that contact the outer surface of the outer layer 110. That is, those portions of the inner layer 108 that exclude the tie / adhesive layer 128 will not include etching. For example, it is contemplated that no etching will be included between the inner surface of the folded portion 118 of the inner layer 108 and the base portion 122 of the outer layer 110. The exclusion of etching on the portions where the outer surfaces of the inner layer 108 and the outer layer 110 are in direct contact helps facilitate release of the inner surface of the folded portion 118 and the outer layer 110 during expansion of the sheath 100.

[0115] The wall thickness of the inner layer 108 can vary, but in some examples, the wall thickness of the inner layer 108 ranges from about 0.002 inches to about 0.006 inches (including about 0.002 inches, about 0.003 inches, about 0.004 inches, about 0.005 inches, and about 0.006 inches). In other examples, the wall thickness of the inner layer 108 ranges from about 0.003 inches to about 0.005 inches. In further examples, the wall thickness of the inner layer 108 ranges from about 0.0035 inches to about 0.0045 inches (including about 0.0035 inches, about 0.0040 inches, and about 0.0045 inches).

[0116] As described above, the sheath 100 includes an outer layer 110 that exerts a radially inward force on the inner layer 108. Generally, the outer layer 110 can include a polymeric material. As described above, the outer layer 110 can be comprised of PTFE, polyimide, PEEK, polyurethane, nylon, polyethylene, polypropylene, polyamide, polyether block amide, polyether block ester copolymer, thermoset silicone, latex, polyisoprene rubber, high density polyethylene (HDPE), Tecoflex™, or combinations thereof. In an illustrative example, the inner layer 108 can include PTFE and the outer layer 110 can include a combination of HDPE and Tecoflex™. The outer layer 110 can have a wall thickness of about 0.007 inches to about 0.013 inches (including about 0.007 inches, about 0.008 inches, about 0.009 inches, about 0.010 inches, about 0.011 inches, about 0.012 inches, and about 0.013 inches). In another example, the outer layer 110 can have a wall thickness in the range of about 0.008 inches to about 0.012 inches. In another example, the outer layer 110 can have a wall thickness in the range of about 0.009 inches to about 0.011 inches.

[0117] As described above, the sheath 100 includes an outer jacket 140 that extends over and encases the outer layer 110. While the outer layer 110 may be discontinuous in that it includes slits or cuts to form the overlapping and base portions 120, 122, as described above, the outer jacket 140 may include a continuous outer layer that covers the inner layer 108 and the outer layer 110.

[0118] The outer jacket 140 may be constructed from an elastomeric material, such as a soft polymeric material that has good elasticity while also being abrasion and tear resistant. Generally, the outer jacket 140 has a relatively low tensile modulus compared to the inner layer 108 and the outer layer 110. Exemplary materials for the outer jacket 140 include thermoplastic polyurethanes, such as, for example, Neusoft and Tecoflex™ 80A B20. In some examples, the outer jacket 140 comprises an elastomer (e.g., an elastomer (elastic polymer) having a Shore hardness (durometer) in the range of about 10 to about 95 Shore A. The outer jacket 140 may include an elastomer having an elongation at break in the range of about 40% to about 800% (including about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 100%, about 150%, about 200%, about 250%, about 300%, about 350%, about 400%, about 450%, about 500%, about 550%, about 600%, about 650%, about 700%, and about 800%). The outer jacket 140 can include an elastomer having a wall thickness ranging from about 0.003 inches to about 0.015 inches (including about 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches, 0.009 inches, about 0.010 inches, about 0.011 inches, about 0.012 inches, about 0.013 inches, about 0.014 inches, and about 0.015 inches). The wall thickness is measured radially between the inner surface of the outer jacket 140 and the outer surface of the outer jacket 140.

[0119] In some examples, the outer jacket 140 includes a single material or combination of materials that has a constant thickness along the entire length of the outer jacket 140. In alternative examples, the material composition and / or wall thickness may vary along the length of the outer jacket 140. For example, the outer jacket 140 may comprise one or more segments, with the composition and / or thickness varying from segment to segment. In one example, the durometer rating of the composition varies along the length of the outer jacket 140 such that a segment near the proximal end includes a stiffer material or combination of materials, while a segment near the distal end includes a softer material or combination of materials. Similarly, the wall thickness of the outer jacket 140 in a segment near the proximal end may be thicker / greater than the wall thickness of the outer jacket 140 near the distal end.

[0120] 19 and described in more detail below in connection with FIGS. 17-21, the outer jacket 140 includes one or more axial reinforcing members 145 that extend longitudinally along all or a portion of the outer jacket 140. The reinforcing members 145 provide rigidity and prevent axial bunching of the outer jacket 140 during insertion into the patient's vasculature, while not sacrificing the low radial expansion force of the outer jacket 140.

[0121] As illustrated in FIG. 3, the sheath 100 can include a tapered segment adjacent to a flared end portion at the proximal end of the sheath 100. The tapered segment and the flared end portion 114, referred to as the strain relief section 26, help to ease the transition between the smaller diameter portion of the sheath 100 and the sheath hub 20. The thickness and / or composition of the outer jacket 140 can be adjusted to increase the durometer and / or stiffness along the strain relief section. Because this portion of the sheath 100 is typically outside the patient's body during the procedure, providing the outer jacket 140 with an increased durometer and / or stiffness along the strain relief section helps to withstand blood pressure that would otherwise "inflate" the outer jacket 140 with bodily fluids / blood. As a result, this allows the sheath 100 to have a relatively stiff proximal end at the point of introduction of the delivery device, while still having a relatively soft distal tip at the point of entry into the patient's vasculature.

[0122] The outer jacket 140 can be bonded to the outer layer 110 to prevent the outer jacket 140 from sliding over and "shrinking" in response to frictional forces applied by surrounding tissue during insertion of the sheath 100 into the patient's vasculature. For example, the outer jacket 140 can be bonded at the proximal and / or distal ends of the outer layer 110. At the proximal and distal ends, the outer jacket 140 can be bonded to the outer layer 110 around the entire circumference of the outer layer. At the distal end of the sheath 100, the outer jacket 140 can alternatively be bonded to the inner layer 108. For example, the outer jacket 140 can be bonded to a distal end face of the inner layer 108.

[0123] As illustrated in FIG. 12, the outer jacket 140 may be bonded 144 to the outer layer 110 at a circumferential location opposite the folded portion 118 of the inner layer 108. As provided in FIGS. 13-14, the bond 144 may be a spot bond or a straight bond line extending along all or a portion of the outer layer 110. As provided in FIG. 12, the bond 144 line / spot will also have a width that extends circumferentially around the outer layer 110. For example, the bond line may cover about 5° to about 90° (including about 5°, about 10°, about 15°, about 20°, about 25°, about 30°, about 35°, about 40°, about 45°, about 50°, about 55°, about 60°, about 65°, about 70°, about 75°, about 80°, about 85°, about 90°) of the circumference of the outer layer 110.

[0124] The outer jacket 140 may be bonded to the outer layer 110 and / or inner layer 108 using any mechanical and / or chemical (e.g., adhesive) fasteners known in the art. In one example, the sheath 100, the outer jacket 140, and the outer layer 110 and / or inner layer 108 may have similar melting temperatures. Thus, an exemplary bonding method includes a thermal bonded connection between the outer jacket 140, the outer layer 110, and / or the inner layer 108. For example, the bond between the outer jacket 140 and the outer layer 110 may be achieved by laser welding and / or thermal compression (e.g., using thermal compression jaws), allowing the location of the bond line to be precisely controlled.

[0125] 9 and described above with respect to FIG 6, an adhesive layer 128 (e.g., a tie layer) is provided between the inner layer 108 and the outer layer 110 to at least partially adhere the inner layer 108 to the outer layer 110. That is, the adhesive layer 128 is selectively provided / located between the inner layer 108 and the outer layer 110 to join the inner and outer layers 108, 110 at selected locations of the adhesive layer 128.

[0126] As illustrated in FIG. 9 (and FIG. 6 ), the adhesive layer 128 is provided on the outer surface of the inner layer 108 and / or the inner surface 130 of the outer layer 110. For example, the adhesive layer 128 may be provided partially or completely around the outer surface of the inner layer 108. Additionally or alternatively, the adhesive layer 128 may be provided partially and / or completely around the inner surface 130 of the outer layer 110. As illustrated in FIG. 9 , the adhesive layer 128 extends between the outer layer 110 and the overlapping folded portion 118 of the inner layer 108. That is, the adhesive layer 128 extends between the outer surface of the folded portion 118 of the inner layer 108 and the corresponding inner surface of the overlapping portion 120 of the outer layer 110. As illustrated in FIG. 9 , the adhesive layer 128 does not extend between the inner surface of the overlapping folded portion 118 of the inner layer 108 and the corresponding surface of the base portion 122 of the outer surface of the outer layer 110. Eliminating the adhesive layer 128 on the portion of the sheath between the inner surface of the folded portion 118 and the base portion 122 facilitates expansion of the sheath and prevents undesirable bonding / adhesion between the inner and outer layers 108, 110 at this location.

[0127] The adhesive layer 128 may include a material having a Shore A hardness (durometer) of less than about 90A. For example, the adhesive layer 128 may include a thermoplastic polyurethane, such as an aliphatic polyether-based thermoplastic polyurethane (TPU). An example of a TPU is Tecoflex™ 80A. The adhesive layer 128 may also be comprised of an aromatic polyether or polyester-based thermoplastic polyurethane, such as Pellethane™ 80A. The adhesive layer may also be comprised of a polyolefin or polyamide, including, for example, a maleic anhydride modified polyolefin (PE, PP, or EVA), such as Orevac™ resin.

[0128] The thickness (wall thickness) of adhesive layer 128 can vary, but in some examples, the wall thickness of the adhesive layer ranges from about 0.002 inches to about 0.005 inches (including about 0.002 inches, about 0.003 inches, about 0.004 inches, and about 0.005 inches). In other examples, the wall thickness of adhesive layer 128 ranges from about 0.0025 inches to about 0.0040 inches (including about 0.0025 inches, about 0.0030 inches, about 0.0035 inches, and about 0.0040 inches). In further examples, the wall thickness of adhesive layer 128 ranges from about 0.0025 inches to about 0.0035 inches (including about 0.0025 inches, about 0.0030 inches, and about 0.0035 inches).

[0129] In some examples, the sheath 100 can include a lubricant to reduce friction and facilitate expansion / contraction between the outer layer 110 and the outer jacket 140. The lubricant 142 allows the outer layer 110 and the inner layer 108 to easily expand under the outer jacket 140, ensuring that the hemostatic and atraumatic benefits achieved by the addition of the outer jacket 140 do not include the pushing force capabilities of the sheath 100. That is, the lubricant 142 reduced the pushing force required to move the prosthetic device through the central lumen 116 of the inner layer 108 during delivery of the prosthetic device and corresponding local expansion of the sheath 100.

[0130] As illustrated in FIG. 11 , the lubricant 142 may be selectively applied along the outer surface of the outer layer 110 proximate the longitudinally extending edge 126 of the overlapping portion 120. In some examples, a portion of the folded portion 118 of the inner layer 108 extends along the outer surface of the outer layer 110 beyond the longitudinally extending edge 126 of the overlapping portion 120. In this example, the lubricant 142 is also provided along the protruding portion, the folded portion 118 of the inner layer 108 extends along the outer surface of the outer layer 110 (beyond the edge 126). In this location, the lubricant 142 also reduces friction between the outer jacket 140 and the inner layer 108 during expansion of the sheath 100. As illustrated in FIG. 11 , the lubricant 142 extends around the circumference of the outer layer 110 beyond the protruding portion of the folded portion 118.

[0131] The lubricant is applied as a band (or spot) that extends both circumferentially and longitudinally along the outer layer 110 (and the protruding portion of the inner layer 108). In the exemplary sheath 100, the lubricant 142 is applied as a band that extends both circumferentially around the outer layer 110 and longitudinally along the length of the outer layer 110. To prevent migration, the lubricant 142 may be comprised of a thermosetting material, e.g., a material that can be cured at room temperature. As a result, the material can be applied at desired locations along the outer layer 110 and will not migrate during assembly and / or use of the sheath 100. The lubricant 142 may be comprised of a medical grade lubricant, such as silicone. Exemplary lubricants include platinum catalyzed thermosetting silicone lubricants such as NuSil™ MED10-6670 (thermosetting), medical grade curable silicone lubricants including PTFE lubricants such as Duraglide™ (curable at room temperature) and / or CHRISTO-LUBE™.

[0132] FIG. 15 illustrates an additional example of the sheath 100 of FIG. 3. In this example, the sheath 100 can include a coiled wire 160 or a coiled wire mesh along the length of the sheath 100. The coiled wire 160 provides uniform bending of the sheath and prevents kinking. The coiled wire 160 can be embedded in the outer layer 110. For example, the coiled wire 160 can be co-extruded with the outer layer 110. Alternatively, the coiled wire 160 can be provided between the outer layer and the adhesive layer 128. In another example, the coiled wire 160 is at least partially embedded in both the outer layer 110 and the adhesive layer 128. For example, the coiled wire 160 can be provided on the outer surface of the adhesive layer 128 and the outer layer 110 is reflowed.

[0133] 16, the coiled wire 160 defines a helical shaped path around the longitudinal axis of the sheath 100. An example of the coiled wire 160 includes overlapping helical shaped paths around the longitudinal axis of the sheath 100, resulting in a continuous diamond shaped pattern along the length of the sheath.

[0134] The coiled wire 160 may be comprised of a metal or polymer wire. For example, the coiled wire 160 may be comprised of PET, PEEK, stainless steel, and / or Nitinol. The coiled wire 160 may be comprised of a flat wire, a round wire, or a combination thereof. The individual wires of the coiled wire 160 may have a diameter / thickness ranging from about 0.002 inches to about 0.008 inches (including about 0.002 inches, about 0.003 inches, about 0.004 inches, about 0.005 inches, about 0.006 inches, about 0.007 inches, about 0.008 inches). In another example, the individual wires of the coiled wire 160 may have a diameter / thickness ranging from about 0.004 inches to about 0.007 inches. In a further example, the individual wires of the coiled wire 160 may have a diameter / thickness of about 0.006 inches. The pitch / distance between adjacent coils of the coiled wire 160 can correspond to the diameter / thickness of the coiled wire. For example, if the diameter / thickness of a single coil of the coiled wire is about 0.006 inches, then the spacing / pitch between the wire and the next adjacent coiled wire is about 0.006 inches.

[0135] 17-21 show side and cross-sectional views of an exemplary outer jacket 140. As illustrated above, the outer jacket 140 includes one or more axial reinforcing members 145 extending longitudinally along all or a portion of the outer jacket 145. The reinforcing members 145 may be disposed circumferentially between the inner and outer polymer layers at a predetermined distance from each other as individual strips. FIG. 19 is a cross-sectional view of the outer jacket 140 taken along section line BB of FIG. 17. As provided in FIG. 19, the outer jacket 140 includes three reinforcing members 145. In some examples, the outer jacket 140 includes only one reinforcing member 145 (FIG. 21). In other examples, the outer jacket includes up to eight reinforcing members 145. When more than one reinforcing member 145 is used, the reinforcing members are evenly spaced around the circumference of the outer jacket 140. As further illustrated in FIG. 19, the reinforcing members 145 may have a rectilinear shape (e.g., rectangular) in cross section. However, any other regular or irregular shapes are contemplated. The reinforcing members 145 have a finite width that is less than the circumference of the outer jacket 140. The total combined width (w) of the reinforcing members 145 may range from 10% to 50% of the circumference of the outer jacket 140. FIG. 20 includes an enlarged partial view of the outer jacket 140 of FIG. 19. As provided in FIG. 20, the circumferential width of the reinforcing members 145 may range from 0.025 inches to 0.100 inches. In embodiments where the reinforcing members 145 are present as one or more strips circumferentially disposed along the length of the outer jacket 140, it is further understood that the width of the reinforcing members 145 may be the same along the length or may vary along the length. In embodiments where the width of the reinforcing members 145 varies along the length of the outer jacket 140, such reinforcing members 145 may have any of the width values ​​disclosed above. In still further embodiments, the at least one reinforcing member 145 is configured to provide axial reinforcement to the outer jacket 140 and, consequently, to a sheath in which the outer jacket 140 may be used. In such exemplary embodiments, the at least one reinforcing member 145 may be disposed along the length of the outer jacket 140 or along a portion of the length of the outer jacket 140.In some embodiments, at least the portion of the length of the outer jacket 140 where the reinforcing member 145 is disposed is located at the distal and / or proximal ends of the outer jacket 140. In yet other embodiments, the reinforcing member 145 may also be located anywhere along the length of the outer jacket 140.

[0136] 19, the outer jacket 140 includes a two-layer structure, i.e., an inner layer 146 and an outer layer 147, where the outer layer provides abrasion resistance (e.g., between the sheath and the calcific lesion) and better resistance to hydrophilic coating processes, and the inner layer is a more lubricious material (e.g., to prevent adhesion of the outer jacket to the outer layer of the sheath during expansion) and provides higher pressure or expansion resistance and hemostasis. In some embodiments, the inner layer 146 (first polymer layer) forms the inner surface of the outer jacket 140, the outer layer 147 (second polymer layer) forms the outer surface of the outer jacket, and the reinforcing member 145 is disposed between the outer surface of the inner layer 146 and the inner surface of the outer layer 147.

[0137] In some examples, the inner layer 146 is constructed from Pebax or polyurethane having a Shore 25D to 35D. In some examples, the inner layer 146 includes PTFE powder, optional inorganic fillers, and optional adhesion reducing additives to reduce friction as the sheath outer layer 110 expands by sliding against the outer jacket 140. In some examples, the outer layer 147 of the outer jacket 140 is constructed from a polyurethane or polyurethane / styrene block copolymer (SBC) having a Shore A durometer lower than about 60, such as Neusoft 597-50A having a Shore A hardness of about 55A. In a particular example, the inner layer 146 is constructed from a polyether block amide such as Pebax having a Shore D durometer less than about 35.

[0138] In still further exemplary and non-limiting embodiments, the inner layer 146 forms an inner surface of the outer jacket and includes a first compound composition including greater than 0% and less than 100% by weight of a polymer including a polyether block amide, a polyurethane, or a combination thereof, based on the total weight of the first compound composition, less than about 65% inorganic filler, based on the total weight of the first compound composition, and up to about 20% solid lubricant filler, based on the total weight of the first compound composition.

[0139] Any of the inorganic fillers and solid lubricant fillers disclosed above may be present in any amount disclosed. For example, the inorganic filler may include bismuth oxide chloride, barium sulfate, bismuth subcarbonate, calcium carbonate, aluminum trihydrate, barite, kaolin clay, limestone, or any combination thereof. In yet other embodiments, the inorganic filler may be present at least 10% by weight. In still further embodiments, the inorganic filler may be present in an amount of less than about 50% by weight based on the total weight of the first compound composition. In yet further embodiments, the solid lubricant filler may include a PTFE filler. The first compound may also include any of the additives disclosed above. For example, the compound may include at least one tack-reducing compound in an amount of about 1% to about 20% by weight.

[0140] In still further exemplary embodiments, the polymer present in the first compound can have a Shore D of about 20D to about 35D, including exemplary values ​​of about 22D, about 25D, about 27D, about 30D, and about 32D.

[0141] In still further embodiments, the durometer of the polymer in the inner layer 146 (first polymer layer) composition at the proximal end of the outer jacket 140 can be different from the durometer of the polymer in the inner layer 146 (first polymer layer) composition at the distal end of the outer jacket 140. In still further embodiments, the polymer in the first compound can also include PEBAX®, while in other embodiments, the polymer in the first compound can include polyurethane. In still further embodiments, the first compound can also include polyamide.

[0142] In still further embodiments, the outer layer 147 (second polymer layer) can include any of the polymers disclosed above. In some embodiments, the outer layer 147 can include a second compound composition including greater than 0% to 100% by weight of a second polymer including a polyether block amide, a polyurethane, or a composition thereof. In still further embodiments, the outer layer 147 can include a polyamide. In still some other embodiments, the second compound can also include any of the fillers or additives disclosed above. On the other hand, in some embodiments, the second compound does not include a solid lubricant filler as disclosed herein. On the other hand, in still further embodiments, the second compound can include a tack-reducing additive as described in this disclosure. In some embodiments, the second polymer can be a polyurethane. In still further embodiments, the polyurethane is a thermoplastic polyurethane. On the other hand, in still further embodiments, the second polymer can be a mixture including a polyurethane with a styrene block copolymer. In still further embodiments, the mixture can further include additional polymers and copolymers. For example, an ether-based polymer can be present in the mixture. In some exemplary and non-limiting embodiments, the second polymer can be selected from commercially available polymers sold under the trade name Neusoft™. In still further embodiments, the second polymer can have a Shore A durometer of about 20A to about 75A, including exemplary values ​​of about 25A, about 30A, about 35A, about 40A, about 45A, about 50A, about 55A, about 60A, about 65A, and about 70A. In still further embodiments, the second polymer can have a Shore A durometer of less than 60A. In some exemplary embodiments, the second polymer can be Neusoft™ 597-50A.

[0143] As provided in FIG. 20, the inner layer 146 is thicker than the outer layer 147. Generally, the inner layer has a thickness ranging from 0.0010 inches to 0.0025 inches. In some examples, the inner layer has a thickness ranging from about 0.00154 inches. The outer layer has a thickness ranging from 0.002 inches to 0.004 inches. In some examples, the outer layer has a thickness of about 0.003 inches. In still further embodiments, the inner layer 146 (first polymer layer) can have a thickness of about 1 mil to about 5 mils. In still further embodiments, the outer layer 147 (second polymer layer) can have a thickness of about 1 mil to about 6 mils. In still further embodiments, the thickness of the reinforcing member 145 can be anywhere from about 1 mil to about 6 mils.

[0144] As provided in FIG. 19 and FIG. 20, the reinforcing member 145 is at least partially embedded in the inner layer 146. In some embodiments, the thickness of the reinforcing member 145 is less than the thickness of the inner layer 146. For example, as illustrated in FIG. 20, the reinforcing member 145 has a thickness ranging from 0.0005 inches to 0.0015 inches. In some examples, the reinforcing member 145 has a thickness of about 0.001 inches. In an exemplary configuration, the reinforcing member 145 has a thickness of 0.001 inches and the inner layer has a thickness of 0.00154 inches. In another embodiment not shown, the reinforcing member 145 has a thickness corresponding to the thickness of the inner layer 146. In further embodiments, the reinforcing member 145 has a thickness greater than the thickness of the inner layer 146. In some examples, the inner layer 146 and the reinforcing member 145 are coextruded. Similarly, the inner layer 146, reinforcing member 145 and outer layer 147 are co-extruded with the reinforcing member 145 positioned between the inner and outer layers 146, 147. In other examples, the inner layer 146 is placed over the reinforcing member 145 and the two components are bonded or fused together by at least one of heat or compression.

[0145] As described above, the reinforcing member 145 is constructed from a material that is stiffer than the main body portion of the outer jacket 140 (inner layer 146, outer layer 147) and has a low coefficient of friction (e.g., high density polyethylene). In some examples, the reinforcing member 145 is constructed from a polymer that is compatible with the inner and outer layers, including, for example, high durometer Pebax or polyurethane. The reinforcing member 145 may also be constructed from a material having a Shore D durometer ranging from 45D to 76D.

[0146] In some examples, the reinforcing members are constructed from materials excluding PTFE powder or inorganic fillers, thereby providing axial compressive / tensile stiffness (from the higher durometer material) and friction against axial buildup (without the PTFE powder).

[0147] In a particular example, the outer layer 147 is constructed from NEUSOFT 597-50, the inner layer 146 is constructed from Pebax 25D with PTFE and BaSO4, and the reinforcing member 145 is constructed from Pebax 35D with PTFE and BaSO4. In a further example, the outer layer 147 is constructed from NEUSOFT 597-50, the inner layer 146 is constructed from Pebax 25D with PTFE and BaSO4, and the reinforcing member 145 is constructed from Pebax 4033. In another example, the outer layer 147 is constructed from NEUSOFT 597-50, the inner layer 146 is constructed from Pebax 25D with PTFE and BaSO4, and the reinforcing member 145 is constructed from Pebax 5533.

[0148] In some embodiments, the reinforcing member 145 may include any of the polymers disclosed herein. In some embodiments, the reinforcing member 145 may include the first compound disclosed above. In yet other embodiments, the reinforcing member 145 may include the second compound disclosed above. Meanwhile, in still further embodiments, the reinforcing member 145 may include the first compound. Also, in still further embodiments, the reinforcing member 145 may include any polymer known in the art and suitable for the desired application. In some embodiments, the reinforcing member 145 may include a polyether block amide, a polyurethane, or a combination thereof. Meanwhile, in still further embodiments, the reinforcing member 145 is a polyether block amide, such as PEBAX®. Meanwhile, in still further embodiments, the reinforcing member 145 is a polyurethane. In these exemplary embodiments, the reinforcing member 145 does not include a solid lubricant filler, such as PTFE. In still other embodiments, the reinforcing member 145 does not include an inorganic filler. In still further embodiments, the reinforcing member 145 can include a polymer, including PEBAX® or polyurethane, having a Shore D durometer of about 45D to about 90D, including exemplary values ​​of about 50D, about 55D, about 60D, about 65D, about 70D, about 72D, about 75D, about 80D, and about 85D.

[0149] In still further embodiments, the reinforcing member 145 can comprise a polyolefin, and in still further embodiments, the reinforcing member 145 can comprise polyethylene, polypropylene, graft modified polyethylene, or polypropylene. In still further embodiments, the reinforcing member 145 can comprise grafted low density polyethylene (LDPE), grafted medium density polyethylene, grafted very low density polyethylene (ULDPE), grafted high density polyethylene (HDPE), grafted heterogeneously branched linear low density polyethylene (LLDPE), grafted homogeneously branched linear ethylene polymers and substantially linear ethylene polymers, grafted polypropylene, or ethylene vinyl acetate (EVA), or any combination thereof. In such exemplary embodiments, maleic anhydride or acrylic acid can be used to graft the polymers disclosed above. In still further embodiments, at least one reinforcing member 145 can comprise maleic anhydride or acrylic acid grafted low density polyethylene. In still further embodiments, at least the reinforcing member 145 can comprise maleic anhydride or acrylic acid grafted polypropylene. In yet further embodiments, the reinforcing member 145 can include maleic anhydride or acrylic acid grafted ethylene vinyl acetate. In still further embodiments, the reinforcing member 145 can include a maleic anhydride grafted polyolefin sold under the trademark OREVAC®.

[0150] In some embodiments, the reinforcing member 145 can bond the inner layer 146 and the outer layer 147 together and can also assist in bonding the elongated tube as a whole to the inner member of the sheath. In one example, the reinforcing member 145 is constructed from heat-bondable strips of tie layer material. The tie layer material is made of a polyolefin backbone, including, for example, LDPE, LLDPE, EVA, HDPE, PP, or polyolefin copolymers, with grafted functional groups, such as maleic anhydride or acrylic acid, as described below. The tie layer is thermally bonded to the polyolefin-like HDPE inner layer 146 and extruded as strips of the polyamide, copolyamide, or polyurethane layer of the outer jacket 140. Possible tie layer materials for the heat-bondable tie layer include OREVAC® grafted polyolefins available from Arkema. In some examples, maleic anhydride grafted LLDPE (linear low density polyethylene) Orevac 18300M is used as strips. In some examples, the heat bondable strips are fused to the inner layer 146 using heat and / or compression.

[0151] In still further embodiments, the outer jacket 140 disclosed herein with a reinforcing member may exhibit an expansion force of less than about 50 N. In still further embodiments, the outer jacket disclosed herein with a reinforcing member may exhibit a burst pressure of greater than about 8 psi.

[0152] 24-27 and 31-32 show an introducer sheath system 1200 that includes a gasket 1202 mounted on the introducer sheath 100. The gasket 1202 maintains integrity between the various layers of the sheath 100 and prevents blood loss through the sheath 100.

[0153] For example, during a transcatheter aortic valve replacement (TAVR) procedure, the sheath 100 is used to provide access to the patient's vasculature (see, e.g., FIG. 22). To maintain hemostasis, it is important to ensure that blood cannot leak through the sheath 100 from the patient's blood vessels. Although the sheath hub 20 (FIGS. 2-3) includes valves and / or seals to prevent blood loss through the sheath hub 20, blood loss can occur through the sheath 100 body itself. Hemostasis can be compromised if blood from the patient's arteriotomy penetrates between the inner layer 108 / outer layer 110 and the outer jacket 140, which can occur after valve expansion causes an intentional break between the sheath layers at the distal tip.

[0154] When this occurs, the outer jacket 140 is the only sheath element that resists blood pressure and maintains hemostasis. As mentioned above, the outer jacket 140 is made of a compatible material to allow for easy expansion of the various layers of the sheath 100. As a result, a sufficiently high blood pressure can cause the outer jacket 140 to "bulge" which can lead to rupture of the outer jacket and subsequent blood loss (see, e.g., FIG. 23). For portions of the sheath 100 that are within the patient's blood vessel, ballooning does not occur because the blood pressure in the vessel is the same as the pressure within the sheath 100. However, for portions of the sheath 100 that are outside the patient, there is no pressure equalization on the outside of the sheath 100 and ballooning of the outer jacket 140 can occur.

[0155] The portion of the sheath 100 that remains outside the patient's body can vary and depend on the patient's size and anatomy, as well as the physician's preference. However, strengthening the material of the outer jacket 140 to prevent ballooning can result in an increase in the force required to expand the various layers of the sheath 100, which in turn increases the amount of pushing force required to advance the delivery system through the sheath 100, making the procedure more difficult for the clinician.

[0156] As described herein, the movable gasket 1202 is provided to prevent the outer jacket 140 from ballooning over the portion of the sheath 100 that remains outside the patient's body during the procedure, while not adversely affecting the force to expand the sheath 100.

[0157] The gasket 1202 is positioned over the outer diameter of the sheath 100 and shrinks the outer jacket 140 of the sheath 100 over the delivery device 10 (e.g., the implant 12 and / or catheter) and / or various layers of the sheath 100 (e.g., the inner layer 108 and the outer layer 110), providing a movable elastomeric seal that prevents blood flow proximal to the gasket 1202 and subsequent ballooning of the sheath 100, regardless of the length of the sheath 100 inserted into the patient.

[0158] The gasket 1202 includes a gasket body 1206, a proximal end 1212, and a distal end 1214. The gasket body 1206 has an inner surface 1208 and an outer surface 1210 opposite and spaced apart from the inner surface 1208. The inner surface 1208 and the outer surface 1210 each extend between the proximal end 1212 and the distal end 1214 of the gasket body 1206. The inner surface 1208 of the gasket body 1206 defines a lumen 1216 having a uniform diameter therethrough, the lumen providing a radially inward force that results in a consistent sealing surface along the axial length of the inner surface 1208 of the gasket 1202. The inner surface 1208 has an inner diameter sized and configured to receive the introducer sheath 100 within the lumen 1216 of the gasket 1202. The gasket 1202 is expandable to accommodate a medical device, such as an expandable heart valve, passing through the lumen of the sheath 100 (and the lumen 1216 of the gasket 1202). The gasket 1202 is elastically movable between an unexpanded configuration having an unexpanded diameter and an expanded configuration having a larger expanded diameter, allowing the lumen 1216 to accommodate devices of various sizes therethrough and conform to the size of the sheath 100 when the sheath 100 is disposed within the lumen 1216 of the gasket 1202. The gasket 1202 is biased toward the unexpanded diameter such that the gasket 1202 maintains the unexpanded diameter until a threshold force is applied to the gasket 1202 to elastically expand the gasket 1202. The gasket body 1206 expands from the unexpanded diameter toward the expanded diameter when it is subjected to a threshold radial force against the inner surface 1208 of the gasket body 1206 that overcomes the elastic force provided by the gasket body 1206.

[0159] The proximal end 1212 of the outer surface 1210 defines a proximal outer diameter, and the distal end 1214 of the outer surface 1210 defines a distal outer diameter. In some examples, the proximal and distal outer diameters are equal and project radially outward from a portion of the outer surface 1210 extending between the proximal end 1212 and the distal end 1214, as shown in FIGS. 24-25. In other examples, the outer diameters at the proximal and distal ends 1212 and 1214 are equal and have a uniform diameter with the outer surface 1210 extending between the proximal and distal ends 1212 and 1214. For example, FIG. 26 shows an example where the proximal outer diameter is equal to the distal outer diameter, each having a uniform diameter with the outer surface 1210 of the gasket 1202 extending therebetween. In other examples, the outer surface 1210 tapers toward the distal outer diameter such that the distal outer diameter is smaller than the proximal outer diameter. For example, FIG. 27 shows an example where the proximal diameter is larger than the distal diameter. In the example shown in FIG. 27, the distal outer diameter is sized and configured to be received at least partially within and / or against the inner diameter of a vascular closure device and / or percutaneous suture, such as Perclose ProGlide™ by Abbot, Angi-Seal™ by Terum, Prostar XL™ by Abbot, MANTA™ by Telflex, and / or combinations thereof. For example, the distal end 1214 of the gasket 1202 can include a tapered outer surface 1210 configured to engage a vascular closure device / suture extending around at least a portion of the gasket 1202. The taper is also sized to allow the gasket 1202 to be positioned at least partially within and / or against an opening in a blood vessel. The gasket 1202 further includes a flared surface at the proximal end 1212 adjacent the proximal outer diameter that is sized and configured to provide a gripping surface for moving the gasket 1202 proximally and distally along the sheath 100.

[0160] The gasket 1202 is made of an elastomeric material such as silicone rubber, nitrile rubber, polyisoprene, neoprene, santoprene, or any other elastomer suitable for providing sealing pressure against the folds of the sheath 100 when the sheath 100 / gasket 1202 is both expanded and unexpanded. In some examples, the gasket 1202 is made from a material having a durometer in the range of 40A to 60A. In a further example, the gasket 1202 is made from LIM6050 silicone rubber having a durometer of 50A, an elastic modulus of 0.22 MPa, and stiffness properties allowing for an elongation of 530%.

[0161] The gasket 1202 shown in FIGS. 24-32 has an unexpanded inner diameter in the range of 0.100 inches to 0.450 inches, or any other diameter suitable for compressing the collapsed portion of the sheath to occlude fluid flow. In some examples, the gasket 1202 has an unexpanded inner diameter in the range of 0.210 inches to 0.315 inches. In further examples, the gasket 1202 has an unexpanded inner diameter in the range of 0.239 inches to 0.263 inches. For example, the gasket 1202 may have an unexpanded inner diameter in the range of 0.263 inches.

[0162] The gasket 1202 has an expanded inner diameter large enough to accommodate an implant passing through the central lumen of the sheath 100. For example, the gasket 1202 has an expanded inner diameter ranging from 0.286 inches to 0.430 inches, or any other expanded diameter suitable for accepting a medical device, such as an expandable heart valve. In some examples, the gasket has an expanded inner diameter ranging from 0.345 inches to 0.360 inches. For example, the gasket 1202 may have an expanded diameter of 0.358 inches.

[0163] In another example, as shown in Figures 28-32, the gasket 1202 includes a housing 1250 that extends at least partially around the gasket body 1206. The housing 1250 helps to maintain the position of the gasket body 1206 and allows the assembly to be sutured in place at the patient's skin level. Figure 31 shows a gasket 1202 with a corresponding housing 1250 mounted on an introducer sheath 100.

[0164] The housing 1250 includes an outer surface extending between a proximal end face 1254 and a distal end face 1256 of the housing 1250. The housing 1250 does not limit the radial expansion of the inner surface 1208 / lumen 1216 of the gasket body 1206, but the housing limits the radial expansion of the outer surface 1210 of the gasket body 1206 to prevent the gasket body 1206 from bending. The housing 1250 includes a cavity 1258 for receiving the gasket body 1206 such that the housing 1250 surrounds at least a portion of the outer surface 1210 of the gasket body 1206. As provided in FIG. 30 , portions of the proximal and distal end faces of the gasket body 1206 are provided within and / or covered by the housing 1250. As such, the gasket body 1206 is sandwiched between the proximal end face 1254 and the distal end face 1256 of the housing 1250. As provided in FIG. 30 , the inner diameter of the cavity 1258 corresponds to the diameter of the outer surface 1210 of the gasket body 1206. As a result, the contact / interference between the inner diameter of the cavity 1258 and the outer surface 1210 of the gasket body 1206 limits or otherwise prevents radial expansion of the outer surface 1210 of the gasket body 1206 during delivery of the medical device. Additionally, the housing 1250 is constructed from a stiffer material than the gasket body 1206 (e.g., polycarbonate), further preventing radial expansion of the gasket body 1206 within the housing 1250.

[0165] 28, the housing 1250 further includes a top gasket opening 1260 and a bottom gasket opening 1262 provided on the proximal end surface 1254 and the distal end surface 1256 of the housing 1250. At least a portion of the gasket body 1206 is exposed at the top gasket opening 1260 and the bottom gasket opening 1262. The diameters of the top gasket opening 1260 and the bottom gasket opening 1262 are larger than the expanded diameter of the introducer sheath 100 such that the top gasket opening 1260 and the bottom gasket opening 1262 do not restrict the expansion of the introducer sheath 100 during delivery of the medical device.

[0166] The housing 1250 includes an attachment mechanism that is used to couple the gasket 1202 to a patient. As provided in FIG. 28, the attachment mechanism includes attachment openings 1264 extending through the housing 1250. As illustrated in FIG. 32 and described in more detail below, a suture passing through the attachment openings 1264 can be used to secure the gasket 1202 to a patient. The attachment openings 1264 are provided on arms 1266 that extend radially from the outer surface 1252 of the housing 1250. The housing 1250 may include one attachment opening 1264. In some examples, as shown in FIG. 28, the housing 1250 includes two attachment openings 1264 evenly spaced radially around the housing 1250, each provided on a corresponding arm 1266 that extends radially from the housing 1250. In a further example, the housing 1250 includes two mounting openings 1264 each provided on a corresponding arm 1266 that is asymmetrically spaced radially about the housing 1250. In yet a further example, the housing 1250 includes three or more mounting openings 1264 each provided on a corresponding arm 1266 that is radially spaced (symmetrically or asymmetrically) about the housing 1250. In some examples, the mounting openings 1264 are provided on / through the housing 1250 and are not included on any radially projecting arms 1266.

[0167] The outer surface 1252 and the arms 1266 define the periphery of the housing 1250. Generally, the periphery defines an overall diameter that is greater than the expanded diameter of the introducer sheath 100. For example, the periphery of the housing has a diameter or overall width that is in the range of 0.430 inches to 0.700 inches. As shown in FIGS. 28-30 , the outer surface 1252 is a generally cylindrical surface from which the arms 1266 protrude. In some examples, the outer surface 1252 has an overall diameter that is greater than the expanded diameter of the introducer sheath 100. It is contemplated that the outer surface 1252 may define any other regular or irregular shape.

[0168] In some examples, the distal outer periphery and / or distal end surface 1256 are sized and configured to be received at least partially within and / or against an inner diameter of a vascular closure device and / or percutaneous suture. For example, the distal end surface 1256 and / or the distal end of the outer surface 1252 may include a taper or features configured to engage a vascular closure device / suture extending around at least a portion of the housing 1250. The taper or features are also sized to allow the housing 1250 to be positioned at least partially within and / or against a vascular opening and / or other patient anatomical structure.

[0169] In addition to the arms 1266, the exterior surface 1252 of the housing 1250 is sized and configured to provide a gripping surface for a user. For example, the exterior surface 1252 may include flared or textured surface features.

[0170] As described with reference to Figures 24-32, the gasket 1202 may be used with any of the introducer sheaths according to various examples described herein. Figures 24-32 show an exemplary sheath 100 for use with the gasket 1202. The sheath 100 includes similar features as described above with reference to Figures 1-21. In the example shown in Figures 24-32, the introducer sheath 100 includes a sheath body 1218 defining a central lumen 1220 extending therethrough. The sheath body 1218 has a reduced diameter portion 1222 adjacent a distal end 1224 of the body and a larger diameter portion 1226 adjacent a proximal end 1228 of the body. The larger diameter portion 1226 functions as a strain relief section as described above, which helps to facilitate the compressive transition of the heart valve moving between the reduced diameter portion 1222 of the sheath 100 and a sheath hub 1229 coupled thereto. The body 1218 further includes an inner layer 1232 that defines at least a portion of a central lumen 1220 of the sheath 100, and an outer layer that extends at least partially around the inner layer 1232. The sheath 100 includes a folded portion 1205 configured to move between a folded configuration and a less folded configuration during expansion of the sheath 100, as described above.

[0171] As shown in FIG. 6 and described above, the inner layer of the sheath 100 can include one or more folded portions 118. The folded portions 118 include a first fold (e.g., a longitudinally extending fold line) and a second fold and an overlapping portion extending circumferentially therebetween (when the sheath is in an unexpanded configuration). The configuration of FIG. 6 allows for radial expansion of the sheath 100 when an outwardly directed radial force is applied from the inside (e.g., by passing a medical device, such as a prosthetic heart valve, through the lumen 116). When a radial force is applied, the folded portions 118 can at least partially separate, straighten, and / or spread, and / or the overlapping portion 120 and base portion 122 of the outer layer 110 can slide circumferentially relative to one another, thereby allowing the diameter of the lumen 116 to expand.

[0172] The sheath 100 is disposed within the lumen 1216 of the gasket 1202. The gasket 1202 may be moved and positioned along the length of the sheath 100 and around the folded portion 1205. The gasket 1202 is radially expandable and contractible to provide an elastic fit against the smaller diameter portion 1222 of the sheath 100 and the larger diameter portion 1226 of the sheath 100 as the sheath 100 is disposed in various longitudinal positions. The gasket 1202 is longitudinally movable along the outer surface of the sheath 100 from the larger diameter portion of the sheath 100 to the distal end 1224 of the sheath 100. The gasket 1202 is elastically coupled to the sheath 100 such that it remains in a fixed position until an axial force is applied to the sheath, such as a physician or technician sliding the gasket 1202 along the sheath 100. The gasket 1202 exerts a radially inward force on the outer layer such that the outer layer is sealed against the inner layer 1232 proximate the location of the gasket 1202. The gasket 1202 resiliently compresses the sheath 100 such that the folded portion 1205 compresses to prevent fluid from passing proximally through the sheath 100.

[0173] A method of using the sheath 100 includes providing a gasket 1202 on an outer surface of the sheath 100. The gasket 1202 is radially expandable and defines a lumen 1216 as described above. The sheath 100 may be pre-positioned inside the inner lumen 1216 of the gasket 1202, but in some examples, the sheath 100 is inserted into the lumen 1216 of the gasket 1202 by a user. The gasket 1202 is advanced proximally relative to the larger diameter portion 1226 of the sheath 100 (e.g., position A in FIGS. 26, 27, 31), thereby elastically expanding the inner diameter of the gasket 1202 and thus expanding the lumen 1216 of the gasket 1202 around the sheath 100. This allows the sheath 100 to be inserted without interference from the gasket 1202. Additionally, with the movable gasket 1202 at the proximal edge of the sheath 100, the gasket 1202 is disposed over the tapered section of the sheath and is positioned at a larger diameter portion 1226 that does not expand during insertion of the delivery system and valve. As a result, the use of the gasket 1202 does not increase the pushing force required for implant delivery.

[0174] The prosthetic device and delivery system are then advanced into the inner lumen 116 of the inner layer 108 / sheath 100. There is little chance of ballooning because there is no leak path between the inner layers (inner layer 108, outer layer 110) and the outer jacket 140 before the delivery system passes the distal tip of the sheath 100 and tears it open. Once the delivery system passes through the sheath 100, the distal tip opens and blood may propagate back through the sheath 100 (e.g., between the inner layers (inner layer 108, outer layer 110) and the outer jacket 140).

[0175] The gasket 1202 advances distally toward the distal end 1224 of the sheath 100 (e.g., position B in FIGS. 26, 27, 31). Because the gasket 1202 is not coupled to the sheath 100, the gasket 1202 is free to slide along the shaft of the sheath 100. In some instances, as shown in FIG. 32, the gasket 1202 advances to a distal position such that the gasket 1202 is directly external to and / or abuts the patient's blood vessel (e.g., an opening in the patient's blood vessel for receiving the introducer sheath system), thereby preventing blood from backing up proximally into the sheath 100 beyond the edge of the skin. Ballooning of the outer jacket 140 is prevented because blood is prevented from passing between the inner layer outside the body and the outer jacket 140. This ensures that deformation of the outer jacket 140 does not occur, preventing blood loss and rupture of the sheath 100 / outer jacket 140 that may occur during the procedure.

[0176] In some examples, the gasket 1202 is at least partially inserted into an opening in the patient's blood vessel such that the distal end 1214 of the gasket 1202 is positioned at least partially inside the blood vessel. The radially inward force imparted by the gasket 1202 urges the inner surface / diameter of the lumen 1216 toward the sheath 100 and the longitudinal axis of the sheath 100. As a result, the outer jacket 140 and / or the outer layer 110 are sealed against the inner layer 108, thereby sealing any openings between the expanded folded portion 1205 and the inner layer 108 and preventing blood from flowing through / into the folded portion 1205 proximal to the location of the gasket 1202 (i.e., preventing blood from flowing through / into the expanded folded portion 1205 outside the patient).

[0177] In some examples, the gasket 1202 moves to a position directly external to and / or abutting the opening of the patient's blood vessel after the prosthetic device / delivery catheter has been advanced into the inner lumen 116 of the sheath 100, but before the prosthetic device / delivery catheter has been advanced beyond the distal opening of the sheath 100 to a location at the delivery site.

[0178] The prosthetic device exerts an outwardly directed radial force on the inner layer 108 of the expandable sheath 100. In some instances, the outwardly directed radial force is transmitted through the inner layer 108, the adhesive layer 128, and the outer layer 110. The lumen 116 of the sheath 100 expands at the axial location of the prosthetic device due to the outwardly directed radial force exerted by the prosthetic device against the inner surface of the lumen during advancement. During expansion of the lumen 116, the first fold (folded edge) of the folded portion 118 is moved circumferentially closer to the second fold (folded edge), shortening the overlapping portion of the folded portion 118 that extends circumferentially between the first and second folds, thereby increasing the circumference of the lumen 116. Without the placement of the gasket 1202, blood / fluid would flow from the blood vessel to the expanded folded portion 1205, particularly the portion of the expanded folded portion 1205 outside the blood vessel. However, the inclusion of the gasket 1202 seals the outer jacket 140 against the outer layer 110 and the inner layer 108, preventing blood flow proximal to the gasket 1202 between the layers and / or into the expanded folded portion 1205.

[0179] When the sheath 100 expands at a particular location (i.e., expands locally at the location of the advancing prosthetic device), the overlapping portion 120 of the outer layer 110 can move circumferentially relative to the base portion 122 as the folded portion 118 of the inner layer 108 at least partially separates and / or unfolds, widening / expanding the elongated gap 132 provided in the outer layer 110. The sheath can thereby expand to accommodate a medical device having a diameter larger than the diameter of the lumen 116 in the resting (unexpanded) configuration. As shown in FIG. 10 (and FIG. 7), in some instances, the folded portion of the inner layer 108 can be fully unfolded, such that the inner layer 108 forms a cylindrical tube at the location of the expanded configuration. As illustrated in FIGS. 9 and 10, the elongated gap 132 is generally aligned with the longitudinal axis of the lumen 116 such that the unfolded portion of the inner layer 108 expands into the gap 132 during expansion.

[0180] In the unexpanded configuration, the sheath 100 can have an outer diameter of less than about 0.030 inches (including less than about 0.029 inches, less than about 0.028 inches, less than about 0.027 inches, less than about 0.026 inches, less than about 0.025 inches, and less than about 0.024 inches). Preferably, the unexpanded sheath 100 has an outer diameter in the range of about 0.024 inches to about 0.026 inches. In the fully expanded configuration, the sheath 100 can have an inner diameter of greater than 0.040 inches. Preferably, the expanded sheath 100 has an inner diameter in the range of 0.046 inches to 0.054 inches (including about 0.046 inches, about 0.047 inches, about 0.048 inches, about 0.049 inches, about 0.050 inches, about 0.051 inches, about 0.052 inches, about 0.053 inches, and about 0.054 inches).

[0181] As described above, the inner layer 108 and the outer layer 110 may be bonded together using an adhesive layer 128. The adhesive layer 128 prevents both longitudinal and radial movement between the inner layer 108 and the outer layer 110. As a result, expansion of the sheath 100 may be limited only to areas excluding the adhesive layer 128. For example, as illustrated in FIG. 9, because the adhesive layer 128 is not provided between the inner surface of the folded portion 118 and the base portion 122 of the outer layer, expansion of the sheath causes the inner surface of the folded portion to extend into the gap 132 created between the first edge 124 and the second edge 126 of the expanded outer layer 110.

[0182] When a prosthetic device is passed through the lumen 116 (or a particular location along the lumen), the lumen 116 of the sheath can at least partially contract back to a non-expanded configuration. Typically, the medical device has an outer diameter that is larger than the diameter of the sheath in its original configuration. The medical device can be advanced toward the implantation site through the expandable sheath, which can locally expand to accommodate the medical device as the device passes through. The radial force exerted by the medical device can be sufficient to locally expand the sheath to an expanded diameter (e.g., expanded configuration) only in the area where the medical device is currently located. When the medical device passes through the particular location of the sheath, the sheath can at least partially contract to the smaller diameter of its original configuration. For example, the outer layer 110 can exert an inwardly directed radial force on the inner layer 108, forcing the inner layer 108 to return to its original folded configuration. Similarly, if a coiled wire 160 is included, the coiled wire can exert an inwardly directed radial force on the outer layer 110 and the inner layer 108, urging them back toward the unexpanded configuration. Similarly, if an outer jacket 140 is included, the outer jacket 140 can exert an inwardly directed radial force on the outer layer 110 and the inner layer 108, urging them back toward the unexpanded configuration. Thus, the expandable sheath can be expanded without the use of an inflatable balloon or other expander.

[0183] A prosthetic device may be delivered to a delivery site within a patient through the distal end of the sheath 100. The prosthetic device may include a self-expanding heart valve or a stent-mounted heart valve. The heart valve may be extended through the distal end of the elongated inner lumen 116 at the delivery site. Once outside of the lumen 116, the heart valve may be expanded / implanted and the sheath 100 and any sutures holding it in place are removed.

[0184] In some examples, the gasket 1202 is advanced proximally over the larger diameter portion 1226 of the sheath 100, and the delivery device is withdrawn proximally through the distal end 1224 of the sheath 100, through the lumen 1220 of the sheath 100, and toward the proximal end 1228 of the sheath 100. The gasket 1202 can be advanced proximally over a majority of the sheath 100 before or after the delivery device is advanced proximally over the larger diameter portion 1226 of the sheath 100.

[0185] In another example, when the exemplary gasket 1202 including the housing 1250 (FIGS. 28-32) is used, the gasket 1202 can be coupled to the patient's skin to secure the gasket 1202 in place. After the prosthetic device / delivery system is advanced into the inner lumen 116 of the sheath 100, the gasket 1202 is advanced distally to a position just above the skin level. Using the attachment openings 1264, the gasket 1202 is coupled to the patient's skin. In some examples, the gasket is sutured to the patient's skin at the attachment openings 1264. With the gasket 1202 coupled to the patient's skin, if the depth of the sheath 100 within the patient's vessel needs to be adjusted during the procedure, the clinician can move the sheath while the moveable seal remains in place. At the end of the procedure, the sutures attaching the gasket 1202 to the skin can be cut and the sheath 100 and gasket 1202 can be removed together.

[0186] The sheaths of the present disclosure can be used with a variety of methods of introducing a prosthetic device into a patient's vasculature. One such method includes positioning an expandable sheath within a patient's blood vessel, passing the device through an introducer sheath that expands a portion of the sheath surrounding the device to accommodate the profile of the device, and automatically retracting the expanded portion of the sheath to its original size after the device has passed through the expanded portion. In some methods, the expandable sheath can be sutured to the patient's skin at the insertion site so that once the sheath is inserted an appropriate distance within the patient's vasculature, it will not move once the implantable device begins to move through the sheath.

[0187] The disclosed examples of the expandable sheath can be used with other delivery and minimally invasive surgical components such as introducers and loaders. In one example, the expandable sheath can be flushed to clear out any air within the sheath, for example, using a flush port (e.g., the flush port extending from the sheath hub 20 in FIG. 3). The introducer can be inserted into the expandable sheath, and the introducer / sheath combination can be fully inserted into the vasculature over a guiding device such as a 0.35 inch guidewire. Preferably, the seam formed by the intersection of the folded portion of the inner layer and the overlapping portion of the outer layer can be positioned so that it is oriented downward (backward). Once the sheath and introducer are fully inserted into the patient's vasculature, in some examples, the expandable sheath can be sutured in place at the insertion site. In this way, the expandable sheath can be substantially prevented from migrating once positioned within the patient. The introducer can then be removed, and in some cases, a loader can be used to insert a medical device, such as a transcatheter heart valve, into the sheath. Such methods may additionally include disposing the tissue heart valve in a crimped state on a distal end portion of an elongate delivery device and inserting the elongate delivery device with the crimped valve into and through an expandable sheath. The delivery device may then be advanced through the patient's vascular system to a treatment site where the valve may be implanted.

[0188] In some cases, the gasket is manufactured by injection molding.

[0189] The corresponding structures, materials, acts, and equivalents of all means or steps and functional elements in the following claims are intended to include any structures, materials, or acts for performing functions in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The implementations have been selected and described in order to best explain the principles and practical application of the invention, and to enable those skilled in the art to understand the invention in various implementations, with various modifications suitable for the particular use contemplated.

Claims

1. A gasket comprising: a gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between a proximal end and a distal end of the gasket body, the inner surface defining a lumen; the gasket is resiliently movable between an unexpanded diameter and an expanded diameter; the gasket is biased toward the unexpanded diameter; A gasket configured to expand from the unexpanded diameter towards the expanded diameter when the gasket body is subjected to a threshold radial force against the inner surface of the gasket body.

2. 2. The gasket of claim 1, wherein the proximal end defines a proximal inner diameter and the distal end defines a distal inner diameter, the proximal inner diameter and the distal inner diameter each being sized and configured to receive an introducer sheath within the lumen of the gasket.

3. The gasket of claim 1 or 2, wherein the proximal end defines a proximal outer diameter and the distal end defines a distal outer diameter, the proximal outer diameter being larger than the distal outer diameter.

4. The gasket of claim 3 , wherein the distal outer diameter is sized and configured to be received at least partially within an inner diameter of a vascular closure device.

5. The gasket of any one of claims 1 to 4, wherein the gasket includes a flared surface at the proximal end adjacent the proximal outer diameter.

6. The gasket of claim 5 , wherein the flared surface is sized and configured to provide a gripping surface.

7. The gasket of any one of claims 1 to 6, wherein the gasket includes a tapered surface at the distal end adjacent the distal outer diameter.

8. The gasket of claim 7 , wherein the tapered surface is sized and configured to lie at least partially within a blood vessel.

9. The gasket of any one of claims 1 to 8, wherein the gasket is constructed from an elastomeric material.

10. The gasket of any one of claims 1 to 9, wherein the gasket is constructed from a material having a durometer in the range of 40A to 60A.

11. 11. The gasket of any one of claims 1 to 10, wherein the unexpanded inner diameter ranges from 0.210 inches to 0.315 inches and the expanded diameter ranges from 0.286 inches to 0.430 inches.

12. 1. An introducer sheath system, comprising: A gasket comprising: a gasket comprising a gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between a proximal end and a distal end of the gasket body, the inner surface defining a lumen, the gasket being resiliently movable between an unexpanded diameter and an expanded diameter and biased toward the unexpanded diameter, the gasket body being configured to expand from the unexpanded diameter toward the expanded diameter upon exposure to a threshold radial force against the inner surface of the gasket body; 1. A sheath for delivering a medical device, the sheath comprising: a sheath comprising a sheath body defining a central lumen extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the sheath body and a larger diameter portion adjacent a proximal end of the sheath body, the sheath body comprising an inner layer defining at least a portion of the central lumen of the sheath, and an outer layer extending at least partially around the inner layer; the sheath is disposed within the lumen of the gasket; the gasket exerts a radially inward force on the outer layer such that the outer layer is sealed against the inner layer adjacent a location of the gasket that prevents fluid flow therebetween; The introducer sheath system, wherein the gasket is longitudinally movable along an outer surface of the sheath from the larger diameter portion of the sheath to the distal end of the sheath.

13. The sheath is The system of claim 12 , further comprising a folded portion configured to move between a folded configuration and a less folded configuration during expansion of the sheath.

14. 14. The sheath system of claim 12 or 13, wherein the inner layer includes a folded portion configured to move between a folded configuration and a less folded configuration during local expansion of the sheath.

15. the folded portion comprises a first folded region and a second folded region and an overlap portion extending between the first folded region and the second folded region; 15. The sheath system of claim 14, wherein the first folded region is configured to move proximate the second folded region to shorten the overlap at a local axial location during application of a radially outward force by passage of the medical device, the shortening of the overlap corresponding to a localized dilation of the lumen.

16. 16. The sheath system of claim 15, wherein the first folded region is configured to move away from the second folded region to lengthen the overlap at the local axial location after the outward radial force is removed, the lengthening of the overlap corresponding to a localized constriction of the lumen.

17. the first folded region and the second folded region are circumferentially spaced from one another; The sheath system of claim 15 or 16, wherein the overlap portion extends circumferentially between the first folded region and the second folded region.

18. the inner layer defines a circumferentially continuous layer, the overlapping portion being radially spaced from an outer surface of a non-overlapping portion of the inner layer; The sheath system of any one of claims 15 to 17, wherein the outer layer defines a discontinuous outer layer including a base portion that radially spaces the overlapping portion away from the outer surface of the non-overlapping portion.

19. the proximal end of the gasket defines a proximal inner diameter and the distal end of the gasket defines a distal inner diameter; The sheath system of any one of claims 12 to 18, wherein the proximal and distal inner diameters are each sized and configured to receive the sheath within the lumen of the gasket.

20. The sheath system of any one of claims 12 to 19, wherein the proximal end defines a proximal outer diameter and the distal end defines a distal outer diameter, the proximal outer diameter being larger than the distal outer diameter.

21. The sheath system of claim 20 , wherein the distal outer diameter is sized and configured to be received at least partially within an inner lumen of a vascular closure device.

22. The sheath system of claim 20 or 21, wherein the proximal outer diameter defines a flared surface.

23. The sheath system of claim 22, wherein the flared surface is sized and configured to provide a gripping surface.

24. The sheath system of any one of claims 20 to 23, wherein the distal outer diameter defines a tapered surface.

25. The system of claim 24 , wherein the taper is sized and configured to be located at least partially within a blood vessel.

26. 1. A method of sealing a sheath, comprising: providing a radially expandable gasket defining a lumen; providing a sheath comprising a sheath body defining a central lumen extending therethrough, a reduced diameter portion, and a larger diameter portion proximal to the reduced diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximally of the larger diameter portion of the sheath, thereby elastically expanding a diameter of the lumen of the gasket; inserting the sheath into a patient's blood vessel; inserting a medical device through the central lumen of the sheath; and distally advancing the gasket to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting the diameter of the lumen of the gasket, thereby sealing the sheath and preventing blood flow proximal to the gasket.

27. 27. The method of claim 26, wherein the sheath comprises a sheath body defining the central lumen of the sheath and extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the body and a larger diameter portion adjacent a proximal end of the body, the body comprising an inner layer defining at least a portion of the central lumen of the sheath and an outer layer extending at least partially around the inner layer.

28. 28. The method of claim 26 or 27, wherein sealing the sheath comprises sealing a gap between the inner and outer layers within the sheath.

29. The method of any one of claims 26 to 28, further comprising inserting the gasket at least partially into a patient's blood vessel.

30. advancing the gasket proximally over the larger diameter portion of the sheath; advancing the medical device proximally through the lumen of the sheath; The method of any one of claims 26 to 29, further comprising removing the sheath from the patient's blood vessel.

31. 1. A method of sealing a sheath, comprising: providing a radially expandable gasket defining a lumen; providing a sheath comprising a sheath body defining a central lumen extending therethrough, a reduced diameter portion, and a larger diameter portion proximal to the reduced diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximally of the larger diameter portion of the sheath, thereby elastically expanding a diameter of the lumen of the gasket; inserting a medical device through the central lumen of the sheath; and distally advancing the gasket to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting the diameter of the lumen of the gasket, thereby sealing the sheath and preventing blood flow proximal to the gasket.

32. A gasket comprising: Housing and a gasket body provided at least partially within the housing, the gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between proximal and distal ends of the gasket body, the inner surface defining a lumen; the lumen is resiliently movable between an unexpanded diameter and an expanded diameter; the lumen is biased toward the unexpanded diameter; The gasket is configured to expand from the unexpanded diameter toward the expanded diameter upon exposure to a threshold radial force against the inner surface of the gasket body.

33. 33. The gasket of claim 32, wherein the proximal end defines a proximal inner diameter and the distal end defines a distal inner diameter, the proximal and distal inner diameters each being sized and configured to receive an introducer sheath within the lumen of the gasket.

34. 34. The gasket of claim 32 or 33, wherein the gasket is constructed from an elastomeric material.

35. The gasket of any one of claims 32 to 34, wherein the gasket is constructed from a material having a durometer in the range of 40A to 60A.

36. 36. The gasket of any one of claims 32-35, wherein the unexpanded inner diameter ranges from 0.100 inches to 0.450 inches and the expanded diameter ranges from 0.286 inches to 0.430 inches.

37. The gasket of any one of claims 32 to 36, wherein the housing includes an opening for receiving the gasket body such that the housing surrounds the outer surface of the gasket body.

38. A gasket according to any one of claims 32 to 37, wherein the gasket body is disposed within a housing such that the housing prevents radial expansion of the outer surface of the gasket body.

39. The gasket of any one of claims 32 to 38, wherein at least a portion of a proximal end face and a distal end face of the gasket body are provided within the housing.

40. The gasket of any one of claims 32 to 39, wherein the housing is constructed from a material that is stiffer than the gasket body.

41. The gasket of any one of claims 32 to 40, wherein the housing includes an attachment mechanism.

42. The gasket of claim 41 , wherein the attachment mechanism includes an attachment opening extending through the housing.

43. 43. The gasket of claim 41 or 42, wherein the mounting opening is provided on an arm that extends beyond an outer surface of the housing.

44. The gasket of any one of claims 32 to 43, wherein the periphery of the housing defines an overall diameter greater than an expanded diameter of the introducer sheath.

45. The gasket of any one of claims 32-44, wherein a distal periphery of the housing is sized and configured to be received at least partially within an inner diameter of a vascular closure device.

46. The gasket of any one of claims 32-44, wherein an outer surface of the housing is sized and configured to provide a gripping surface (e.g., a flared or textured outer surface).

47. 47. The gasket of any one of claims 32 to 46, wherein at least a portion of the distal end surface of the housing and / or the distal end surface of the gasket body are configured to lie at least partially within or against the blood vessel and / or other patient anatomical structure.

48. 1. An introducer sheath system, comprising: A gasket comprising: Housing and a gasket comprising: a gasket body provided at least partially within the housing, the gasket body having an inner surface and an outer surface opposite and spaced from the inner surface, both surfaces extending between a proximal end and a distal end of the gasket body, the inner surface defining an inner lumen, the inner lumen being resiliently movable between an unexpanded diameter and an expanded diameter, the inner lumen being biased toward the unexpanded diameter, the inner lumen being configured to expand from the unexpanded diameter toward the expanded diameter upon exposure to a threshold radial force against the inner surface of the gasket body; 1. A sheath for delivering a medical device, the sheath comprising: a sheath comprising a sheath body defining a central lumen extending therethrough, the sheath body having a smaller diameter portion adjacent a distal end of the sheath body and a larger diameter portion adjacent a proximal end of the sheath body, the sheath body comprising an inner layer defining at least a portion of the central lumen of the sheath, and an outer layer extending at least partially around the inner layer; the sheath is disposed within the lumen of the gasket; the gasket exerts a radially inward force on the outer layer such that the outer layer is sealed against the inner layer adjacent the gasket preventing fluid flow therebetween; The introducer sheath system, wherein the gasket is longitudinally movable along an outer surface of the sheath from the larger diameter portion of the sheath to the distal end of the sheath.

49. The sheath is 49. The sheath system of claim 48, further comprising a folded portion configured to move between a folded configuration and a less folded configuration during expansion of the sheath.

50. 50. The sheath system of claim 48 or 49, wherein the inner layer includes a folded portion configured to move between a folded configuration and a less folded configuration during local expansion of the sheath.

51. the folded portion comprises a first folded region and a second folded region and an overlap portion extending between the first folded region and the second folded region; 51. The sheath system of claim 50, wherein the first folded region is configured to move proximate the second folded region to shorten the overlapping portion at a local axial location during application of a radially outward force by passage of the medical device, the shortening of the overlapping portion corresponding to a localized dilation of the lumen.

52. 52. The sheath system of claim 51, wherein the first folded region is configured to move away from the second folded region to lengthen the overlap at the local axial location after the outward radial force is removed, the lengthening of the overlap corresponding to a localized constriction of the lumen.

53. the first folded region and the second folded region are circumferentially spaced from one another; 53. The sheath system of claim 51 or 52, wherein the overlap portion extends circumferentially between the first folded region and the second folded region.

54. the inner layer defines a circumferentially continuous layer, the overlapping portion being radially spaced from an outer surface of a non-overlapping portion of the inner layer; 54. A sheath system according to any one of claims 51 to 53, wherein the outer layer defines a discontinuous outer layer including a base portion that radially spaces the overlapping portion away from the outer surface of the non-overlapping portion.

55. the proximal end of the gasket defines a proximal inner diameter and the distal end of the gasket defines a distal inner diameter; The sheath system of any one of claims 48 to 54, wherein the proximal and distal inner diameters are each sized and configured to receive the sheath within the lumen of the gasket.

56. The sheath system of any one of claims 48 to 55, wherein a distal periphery of the housing is sized and configured to be received at least partially within an inner lumen of a vascular closure device.

57. The sheath system of any one of claims 48 to 56, wherein an outer surface of the housing is sized and configured to provide a gripping surface (e.g., a flared or textured outer surface).

58. The sheath system of any one of claims 48 to 57, wherein at least a portion of the distal end surface of the housing and / or the distal end surface of the gasket body are configured to be positioned at least partially within a blood vessel (e.g., the housing and / or the gasket body may include a tapered surface at the distal end).

59. 1. A method of sealing a sheath, comprising: providing a radially expandable gasket defining a lumen; providing a sheath comprising a sheath body defining a central lumen extending therethrough, a reduced diameter portion, and a larger diameter portion proximal to the reduced diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximally of the larger diameter portion of the sheath, thereby elastically expanding a diameter of the lumen of the gasket; inserting the sheath into a patient's blood vessel; inserting a medical device through the central lumen of the sheath; advancing the gasket distally to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting a diameter of the lumen of the gasket, thereby sealing the sheath and preventing blood flow proximal to the gasket; and securing the gasket to the patient.

60. 60. The method of claim 59, wherein the sheath comprises a sheath body defining the central lumen of the sheath and extending therethrough, the sheath body having the smaller diameter portion adjacent a distal end of the body and the larger diameter portion adjacent a proximal end of the body, the body comprising an inner layer defining at least a portion of the central lumen of the sheath and an outer layer extending at least partially around the inner layer.

61. 61. The method of claim 59 or 60, wherein sealing the sheath comprises sealing a gap between the inner and outer layers of the sheath.

62. 62. The method of any one of claims 59 to 61, wherein the gasket includes an attachment mechanism, and wherein the gasket is secured to the patient with the attachment mechanism.

63. 63. The method of claim 62, wherein the attachment mechanism includes attachment openings, and securing the gasket to the patient includes suturing the gasket to the patient at the patient's skin level by passing a suture through the attachment openings in the gasket and into the patient.

64. 64. The method of any one of claims 59 to 63, further comprising inserting the gasket at least partially into a patient's blood vessel.

65. removing the gasket from the patient; advancing the gasket proximally; advancing the medical device proximally through the lumen of the sheath; The method of any one of claims 59 to 64, further comprising removing the sheath from the patient's blood vessel.

66. 1. A method of sealing a sheath, comprising: providing a radially expandable gasket defining a lumen; providing a sheath comprising a sheath body defining a central lumen extending therethrough, a reduced diameter portion, and a larger diameter portion proximal to the reduced diameter portion; inserting the sheath into the lumen of the gasket; advancing the gasket proximally of the larger diameter portion of the sheath, thereby elastically expanding a diameter of the lumen of the gasket; inserting a medical device through the central lumen of the sheath; advancing the gasket distally to a distal position such that the gasket is exterior to the patient's blood vessel, thereby elastically contracting the diameter of the lumen of the gasket, thereby sealing the sheath and preventing blood flow from the patient proximal to the gasket; and releasably connecting the gasket to the patient.

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