Pre-extended expandable sheath with protective cover

Abstract

Various implementations include an expandable sheath system (300) including a radially expandable sheath (208) with a restraining member (385) that limits the expansion of the sheath, and a method for manufacturing the same.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 522,472, filed on June 22, 2023, which is hereby incorporated by reference in its entirety.

[0002] This application is directed to a sheath for use in catheter - based techniques for repairing and / or replacing heart valves and for delivering implants, such as artificial valves, to the heart through a patient's vasculature.

Background Art

[0003] Endovascular delivery catheter assemblies are used to implant artificial devices, such as artificial valves, at locations inside the body that are not easily accessible surgically or where access without invasive surgery is desirable. For example, aortic, mitral, tricuspid, and / or pulmonary artery artificial valves can be delivered to the treatment site using minimally invasive surgical techniques.

[0004] Percutaneous interventional medical procedures utilize the body's major blood vessels to reach a target site, rather than surgically opening the target area. Many types of disease conditions can be treated through these interventions, including coronary artery occlusion, transcatheter arterial valve replacement (TAVR), and cerebral aneurysms. These techniques involve using wires, catheters, balloons, electrodes, and other thin devices to traverse the length of a blood vessel from the access site to the target site. The device has a proximal end controlled by the clinician outside the body and a distal end inside the body that is involved in treating the disease condition. Percutaneous interventional procedures offer several advantages over open surgical techniques. Firstly, the procedure requires a smaller incision site, reducing the risk of wounds, bleeding, and infection. Percutaneous procedures also cause less tissue damage, thus shortening recovery time. Finally, percutaneous interventional techniques can usually be performed more quickly, reducing overall costs due to fewer clinicians involved in the procedure. In some cases, the need for anesthesia is also eliminated, further accelerating the recovery process and reducing risks.

[0005] A single procedure typically involves the use of several different guidewires, catheters, and balloons to achieve the desired effect. Each tool is inserted one at a time and then sequentially removed from the access site. For example, a guidewire is used to track the correct position within the body. Next, a balloon may 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, an introducer sheath is used to protect local anatomical structures and simplify the procedure.

[0006] An introducer sheath can be used to safely introduce a delivery device into a patient's vascular structure (e.g., the femoral artery). An introducer sheath is a conduit that seals over the blood vessel at the access site to reduce bleeding and vascular trauma caused by the rough edges of the catheter. An introducer sheath typically comprises an elongated sleeve inserted into the vascular structure and a housing containing one or more sealing valves that allow the delivery device to be positioned in fluid communication with the vascular structure with minimal blood loss. Once the introducer sheath is positioned within the vascular structure, the shaft of the delivery device is advanced through the sheath into the vascular structure to deliver the prosthetic device. With an expandable introducer sheath made of a high-elastomer material, vascular dilation can be performed by the passing prosthetic device.

[0007] The force required to advance the delivery system / medical device through the sheath stems from friction between the sheath and the delivery device, the force needed to expand the sheath radially, and the force needed to expand adjacent patient anatomical structures, such as the femoral blood vessels. Excessive pushing force can lead to physician fatigue and errors, and prolong the time required to complete the procedure.

[0008] The pushing force required to advance the delivery system and / or medical device through the sheath depends on a variety of factors, including the patient's anatomical structure, the profile of the crimped valve / delivery system, and the sheath design / manufacturing. For example, an expandable sheath, formed from a highly elastic material and partly containing one or more folds to aid in expansion, expands as the implant device is inserted through the sheath. These sheaths may include a strain relief section that extends along / above the outer surface of the sheath (e.g., at the proximal end) and forms a smooth transition from the sheath hub to the sheath. The strain relief section helps limit the expansion of the sheath below and ensure hemostasis between the patient-inside portion of the sheath and the sheath hub (outside the patient). Because the strain relief section resists expansion, a higher pushing force is required as the delivery device / system and implant are introduced into and advance through the sheath / strain relief section. Furthermore, the recent trend in heart valves, which includes thicker PVL skirts, increases the crimp profile of the heart valve / delivery device, which can result in even greater compressive forces through the sheath, particularly in the strain relief portion.

[0009] One method to reduce the pushing force required to advance the delivery device through the sheath is to pre-expand the sheath and / or strain-relieving portion by passing a relatively large dilator (e.g., a 22-French dilator) through the sheath. This is done during sheath preparation, before sheath insertion into the patient, and / or when the sheath is at least partially inserted into the patient. The challenge with this method is that advancing the dilator into the sheath can be difficult in terms of the user's physical strength (i.e., grip and arm strength). Furthermore, it is important to avoid splitting the sheath and / or its distal end while ensuring the dilator passes completely through to the distal end of the sheath, as this could cause difficulties or vascular damage during the insertion / removal process of the delivery device.

[0010] Therefore, there remains a need for devices, systems, and methods that provide a sheath that includes a strain-relieving portion, allowing the sheath body to expand, thereby reducing the initial pressing force when introducing the delivery system and implant. [Overview of the Initiative] [Means for solving the problem]

[0011] The implementation of this expandable sheath system can minimize trauma to the vessel, as well as damage to the sheath and prosthetic device, by reducing the compressive force passing through the sheath. Some implementations ensure that the sheath is not damaged when dilates or expands the strain relief portion. Some implementations may feature a sheath with a smaller profile than that of prior art introducer sheaths. Furthermore, some implementations can reduce the time required for the procedure and, because less compressive force is needed and only one sheath is used, the risk of longitudinal or radial vascular tearing or plaque dislodgement can be reduced.

[0012] An implementation of the method of the present disclosure for manufacturing a pre-expanded expandable sheath for delivering a medical device. In one of its basic configurations / implementations, the present disclosure provides a method comprising: providing a radially expandable sheath having a tubular strain-relieving layer; providing a restraining member on the sheath to limit expansion; expanding the sheath; and removing the restraining member. This basic configuration / implementation may preferably provide one or more of the features described elsewhere in the present disclosure, in particular the features of the examples described below. However, it will be understood that the basic configuration may also preferably provide one or more of the features shown in the figures and / or described in conjunction with the figures, as additional or alternative features to the features of the examples described below.

[0013] In some implementations, the method provides a radially expandable sheath comprising a continuous inner layer defining a lumen through which the inner layer comprises a proximal portion and a main portion, the inner layer having a folded portion extending along the length of the inner layer, and a tubular strain-relieving layer provided on the proximal portion of the inner layer, wherein at least a portion of the sheath is configured to locally expand from a non-expandable configuration having a first diameter to an expandable configuration having a second, larger diameter (e.g., in response to a radially outward force applied to the lumen by an expandable element of a dilator and / or medical device), and then locally contract at least partially back toward the non-expandable configuration (e.g., when a dilator and / or medical device passes through the lumen).

[0014] In some implementations, the method involves providing a restraining member positioned on the distal end of a strain-relaxing layer, the restraining member restricting the expansion of the inner layer and at least one adjacent (e.g., lower) portion of the strain-relaxing layer. For example, in some implementations, the restraining member restricts the expansion / unfolding of the folded portion, thereby preventing the seam from propagating axially or opening further radially after pre-expansion.

[0015] In some implementations, the method involves introducing a dilator to the proximal end of the lumen of the sheath, and the dilator includes an expansion element provided thereon.

[0016] In some implementations, the method involves advancing the dilator through the proximal portion of the inner layer such that the dilation element provided on the dilator applies a radially outward force relative to the lumen, causing the inner layer (and / or strain-relieving layer) adjacent to the dilation element to locally dilate from a non-dilation configuration to a dilation configuration.

[0017] In some implementations, the restraining member limits the expansion of the sheath adjacent to the restraining member (e.g., the inner layer and the strain-relaxing layer).

[0018] In some implementations, the method includes heating the sheath. For example, in some implementations, the method includes sterilizing the sheath and / or thermally setting the sheath to an expanded folded configuration.

[0019] In some implementations, the restraining member restricts the unfolding of the folded portion of the inner layer adjacent to the restraining member as the sheath moves from a non-expanded configuration to an expanded configuration during the advancement of the expander through the proximal portion of the inner layer.

[0020] In some implementations, the restraining member is provided along the length of the sheath at a position corresponding to the distal end of the strain relaxation layer, and extends along a certain length of the strain relaxation layer from the distal end to the proximal end of the strain relaxation layer, and along a second length of the sheath from the distal end of the strain relaxation layer towards the distal end of the sheath.

[0021] In some implementations, providing the restraining member on the sheath involves coupling the restraining member to at least one of the inner layer or strain-relaxing layer (e.g., coupling in a releasable manner).

[0022] In some implementations, the inner surface of the restraining member includes an adhesive (e.g., a temporary / releasable adhesive) for bonding the restraining member to the sheath.

[0023] In some implementations, the restraining member includes a shrink tube, where bonding the restraining member to at least one of the inner layer or strain-relaxing layer includes providing the restraining member with a shrink process (e.g., a shrink-heating process).

[0024] In some implementations, the method further includes removing the restraining member from the inner layer and the strain-relaxing layer.

[0025] In some implementations, the restraining member is removed after the heating step. For example, in some implementations, the restraining member is removed immediately before the medical procedure.

[0026] In some implementations, the restraining member is removed prior to the heating step.

[0027] In some implementations, the release feature includes removing the sheath from the package that is sized and configured to receive the sheath and provides a radially expandable sheath, and removing the restraining member from the inner layer and the strain relief layer.

[0028] In some implementations, advancing the dilator through the proximal portion of the inner layer includes advancing the expansion element of the dilator aligned with the distal end of the strain relief layer such that the distal end of the strain relief layer is expanded. For example, in some implementations, the proximal end of the tapered portion and / or the distal end of the body portion of the dilator shaft are aligned with the distal end of the strain relief layer.

[0029] In some implementations, advancing the dilator through the proximal portion of the inner layer includes advancing the expansion element of the dilator beyond the distal end of the strain relief layer such that the distal end of the strain relief layer and a portion of the body portion of the inner layer are expanded. For example, in some implementations, the expansion element is used to expand / elongate the length of the body portion of the sheath that extends beyond the distal end of the strain relief layer by 10 - 15 mm.

[0030] In some implementations, by expanding a portion of the body portion beyond the strain relief layer, the corresponding length of the folded portion is at least partially deployed. For example, in some implementations, expanding a portion of the body portion beyond the strain relief layer separates any bonds between the folded layers of the inner layer of the sheath.

[0031] In some implementations, the method further includes removing the dilator from the lumen of the sheath after the heating step is completed. In some implementations, the dilator remains within the sheath during the heating step.

[0032] In some implementations, the method further includes removing the expander from the lumen of the sheath before the heating step.

[0033] In some implementations, at least a portion of the strain-relieving layer is configured to locally expand from a non-expanded configuration at a first diameter to an expanded configuration at a second, larger diameter (e.g., by a dilator and / or a medical device applied to the inner layer by a radially outward force applied to the lumen of the inner layer), and then locally contract back to the non-expanded configuration, at least partially (e.g., when a dilator and / or a medical device passes through the lumen).

[0034] In some implementations, at least a portion of the strain-relieving layer is configured to locally expand from a non-expanded configuration to an expanded configuration in response to a radially outward force applied to the lumen (e.g., the inner layer) by the expander, and then locally contract back to the non-expanded configuration as the expander moves within the lumen; and at least a portion of the sheath is configured to locally expand from a non-expanded configuration to an expanded configuration in response to a radially outward force applied to the lumen of the inner layer by the expander, and then locally contract back to the non-expanded configuration as the expander moves within the lumen.

[0035] In some implementations, the sheath further includes an outer layer provided on an inner layer, the outer layer being discontinuous and including an overlapping portion and a base portion, the overlapping portion overlapping with the base portion, at least a portion of the folded portion of the inner layer being located between the overlapping portion and the base portion, and the strain-relaxing layer extending at least partially onto the outer layer.

[0036] In some implementations, in a non-extended configuration, the folded portion extends circumferentially across the outer surface of the inner layer and / or the outer layer; in an extended configuration, local extension unfolds at least partially the length of the folded portion; and in an extended configuration, local extension of the sheath shifts the length of the overlapping portion circumferentially relative to the base portion.

[0037] In some implementations, in an expanded configuration, local expansion of the sheath forms a gap between the longitudinally extending edges of the outer layer, with at least a portion of the unfolded portion extending into the gap, and a restraining member limits the expansion of the sheath and the width of the gap adjacent to the restraining member.

[0038] In some implementations, the sheath further includes an elastic outer cover that extends at least partially over the sheath (e.g., partially over the inner layer, the outer layer, and / or the strain-relieving layer, and, if included, below the restraining member), the outer cover locally expands and contracts as the medical device advances through the lumen, and the elastic outer cover applies radially inward forces over the sheath (e.g., biasing the inner layer, outer layer, and / or strain-relieving layer toward a non-expanding configuration).

[0039] In some implementations, the sheath further includes a sheath hub fixedly coupled to the proximal end of the sheath, the sheath hub includes a central lumen extending through it and coaxial with the lumen of the sheath, the dilator shaft is sized and configured to be received within the central lumen of the sheath hub (e.g., slidably received), and the dilator includes a dilator hub coupled to the proximal end of the dilator shaft, the method including advancing the dilator through the proximal portion until the dilator hub abuts against the sheath hub, and coupling the dilator hub to the sheath hub before heating the sheath. For example, in some implementations, the dilator hub is coupled to the sheath hub by press-fit, interfer-fit, snap-fit, pin, thread, bayonet fastener, clip, and / or lock key.

[0040] In some implementations, heating the sheath involves heating the sheath to a temperature and duration corresponding to the sterilization process, but during heating, the sheath is not heated to a temperature or duration sufficient to bond the layers of the folded portion together.

[0041] In some implementations, heating the sheath involves heating the sheath to a temperature of 60°C.

[0042] In some implementations, heating the sheath involves heating the sheath for a period exceeding 12 hours (e.g., 24 hours at 60°C, 26 hours at 60°C).

[0043] A further implementation of the present disclosure is a sheath system comprising a radially expandable sheath comprising a continuous inner layer defining a lumen through which the inner layer comprises a proximal portion and a main portion, and a folded portion extending along the length of the inner layer. In some implementations, the expandable sheath comprises a tubular strain-relieving layer provided on the proximal portion of the inner layer. In some implementations, the expandable sheath comprises a restraining member positioned on the distal end of the strain-relieving layer, the restraining member restricting the expansion of the inner layer and at least one adjacent (e.g., base) portion of the strain-relieving layer (e.g., restricting the expansion / unfolding of the folded portion, thereby preventing the seam formed between the outer layer and the inner layer and / or between adjacent layers of the folded portion from propagating axially or radially from further openings after pre-expansion). In some implementations, the sheath system further includes a dilator, sized and configured to be received within the lumen of the inner layer, the dilator including an extended dilator shaft and an expansion element provided thereon. In some implementations, at least a portion of the sheath (e.g., the inner layer and / or strain-relieving layer) is configured to locally expand from a non-expanding configuration with a first diameter to an expanded configuration with a second, larger diameter, and then locally contract towards the non-expanding configuration, at least partially, in response to a radially outward force applied to the lumen by the expansion element of the dilator (and / or medical device), as the dilator (and / or medical device) passes through the lumen. In some implementations, a restraining member restricts the expansion of the sheath adjacent to the restraining member (e.g., the inner layer and / or strain-relieving layer).

[0044] In some implementations, the restraining member limits the unfolding of the folded portion of the inner layer adjacent to the restraining member when the sheath moves from a non-extended configuration to an extended configuration.

[0045] In some implementations, the restraining member is provided along the length of the sheath at a position corresponding to the distal end of the strain relaxation layer, and extends along a certain length of the strain relaxation layer from the distal end to the proximal end of the strain relaxation layer, and along a second length of the sheath from the distal end of the strain relaxation layer towards the distal end of the sheath.

[0046] In some implementations, the restraining member includes at least one of the following: tape, shrink tube, elastic tube, or package feature.

[0047] In some implementations, the restraining member is coupled to the sheath (e.g., detachably). For example, in some implementations, the restraining member is coupled to the inner layer and / or the strain relief layer.

[0048] In some implementations, the inner surface of the restraining member includes an adhesive (e.g., a temporary / releasable adhesive) for bonding the restraining member to the sheath.

[0049] In some implementations, the restraining member includes a shrink tube, which is bonded to at least one of the inner layer or strain-relaxing layer by a shrinking process (e.g., a shrink heating process).

[0050] In some implementations, the restraining member includes a release feature for removing the restraining member from the sheath (e.g., an inner layer and / or strain-relaxing layer).

[0051] In some implementations, the release feature includes at least one of a weakening portion, or a pull tab, and / or a line, integrated with the restraining member. For example, in some implementations, the release feature includes a perforation, a score line, and / or a slit.

[0052] In some implementations, the release feature is incorporated into the package, sized and configured to receive the sheath, and removing the sheath from the package removes the suppression member from the inner layer and strain relaxation layer.

[0053] In some implementations, the expander shaft includes a main body portion adjacent to the proximal end of the expander shaft and a tapered portion extending from the distal end of the expander shaft toward the main body portion, with the expander element provided on the main body portion.

[0054] In some implementations, the extension element is defined by the main body portion of the extension shaft.

[0055] In some implementations, the extension element includes projections extending from the outer surface of the expander shaft. For example, in some implementations, the extension element may include projections of a regular or irregular shape extending from the outer surface of the expander shaft. For example, in some implementations, the projections extend around all or part of the circumference of the expander shaft.

[0056] In some implementations, the diameter of the extension element is 22F. For example, in some implementations, the extension elements of the extender have diameters in the ranges of 12F-24F, 14F-24F, and 14F-22F.

[0057] In some implementations, at least a portion of the strain-relieving layer is configured to locally expand from a non-expanded configuration at a first diameter to an expanded configuration at a second, larger diameter (e.g., by a dilator and / or a medical device applied to the inner layer by a radially outward force applied to the lumen of the inner layer), and then locally contract back to the non-expanded configuration, at least partially (e.g., when a dilator and / or a medical device passes through the lumen).

[0058] In some implementations, at least a portion of the strain-relaxing layer is configured to locally expand from a non-expanded configuration to an expanded configuration in response to a radially outward force applied to the lumen (e.g., the inner layer) by the expander, and then locally contract back to the non-expanded configuration, at least partially, as the expander moves within the lumen.

[0059] In some implementations, the strain relaxation layer includes a proximal portion adjacent to the proximal end of the strain relaxation layer, a distal portion adjacent to the distal end of the strain relaxation layer, and a tapered portion extending between the distal and proximal portions, where the diameter of the proximal portion is greater than the diameter of the distal portion.

[0060] In some implementations, the strain-relaxing layer contains a material that is stiffer and / or less elastic than the inner layer, limiting the expansion of the inner layer.

[0061] In some implementations, the strain relaxation layer includes a material with a higher durometer than the inner layer so that the strain relaxation layer limits the expansion of the sheath (e.g., the inner layer and / or outer layer).

[0062] In some implementations, the strain-relieving layer contains polyurethane. For example, in some implementations, the strain-relieving layer contains high-density polyethylene.

[0063] In some implementations, the length of the strain relaxation layer remains constant when the strain relaxation layer moves from a non-extended configuration to an extended configuration.

[0064] In some implementations, the sheath further includes an outer layer provided on an inner layer, and the strain-relieving layer comprises a material that is harder and / or less elastic than the inner and outer layers, and restricts the expansion of at least one of the inner or outer layers, and the strain-relieving layer comprises a material that has a higher durometer than the inner and / or outer layers, such that the strain-relieving layer restricts the expansion of at least one of the inner or outer layers.

[0065] In some implementations, the sheath further includes an outer layer provided on an inner layer, the outer layer being discontinuous and including an overlapping portion and a base portion, the overlapping portion overlapping with the base portion, at least a portion of the folded portion of the inner layer being located between the overlapping portion and the base portion, and the strain-relaxing layer extending at least partially on the outer layer.

[0066] In some implementations, in a non-extended configuration, the folded portion extends circumferentially across the outer surface of the inner and / or outer layers.

[0067] In some implementations, in the extended configuration, local extension unfolds the length of the folded portion to form the unfolded portion of the inner layer, and in the extended configuration, local extension of the sheath shifts the length of the overlapping portion circumferentially relative to the base portion.

[0068] In some implementations, in an expanded configuration, local expansion of the sheath forms a gap between the longitudinally extending edges of the outer layer, with at least a portion of the unfolded portion extending into the gap, and a restraining member limits the expansion of the sheath and the width of the gap adjacent to the restraining member.

[0069] In some implementations, the total length of the strain relief layer and / or sheath does not change when the sheath and / or strain relief layer move between a non-extended configuration and an extended configuration.

[0070] In some implementations, the lumen of the inner layer is cylindrical in non-expanded configurations and in expanded configurations.

[0071] In some implementations, the inner layer contains PTFE, and the outer layer contains HDPE and / or Tecoflex.

[0072] In some implementations, the inner and outer layers are coupled together.

[0073] In some implementations, the inner and outer layers are thermally bonded together.

[0074] In some implementations, the inner and outer layers are bonded together with an adhesive.

[0075] In some implementations, the strain relaxation layer is coupled to the outer layer and / or the inner layer.

[0076] In some implementations, the strain-relieving layer is thermally and / or adhesively bonded to the outer layer and / or inner layer.

[0077] In some implementations, the inner layer includes woven fabric and / or braided filaments.

[0078] In some implementations, the inner layer contains thread filaments made of PTFE, PET, PEEK, and / or nylon.

[0079] In some implementations, the outer layer includes polyurethane (e.g., high-density polyethylene).

[0080] In some implementations, the sheath system further includes an elastic outer cover extending at least partially over the sheath (e.g., at least partially over the inner layer, outer layer, and / or strain-relieving layer), which locally expands and contracts as the dilator (and / or medical device) advances through the lumen. In some implementations, the elastic outer cover applies a radially inward force over the sheath (e.g., biasing the inner layer, outer layer, and / or strain-relieving layer toward the non-expanding configuration). In some implementations, the elastic outer cover includes PEBAX, polyurethane, silicone, or polyisoprene, or a combination thereof.

[0081] In some implementations, the sheath further includes a sheath hub, which is fixedly coupled to the proximal end of the sheath. In some implementations, the sheath hub includes a central lumen extending through it and coaxial with the lumen of the sheath, and the dilator shaft is sized and configured to be received (e.g., slidably received) within the central lumen of the sheath hub. In some implementations, the dilator includes a dilator hub coupled to the proximal end of the dilator shaft, and the dilator hub is configured to be coupled to the sheath hub. For example, in some implementations, the dilator hub is coupled to the sheath hub by press-fit, interfer-fit, snap-fit, pin, thread, bayonet fastener, clip, and / or lock key.

[0082] In some implementations, the sheath hub includes one or more seals for forming a seal around the outer surface of the delivery device, which are movable through the central lumen of the sheath hub.

[0083] Another implementation of the present disclosure provides a sheath kit system comprising a radially expandable sheath. In some implementations, the expandable sheath comprises a continuous inner layer defining a lumen through which the inner layer comprises a proximal portion and a main portion, as well as a folded portion extending along the length of the inner layer. In some implementations, the expandable sheath comprises a tubular strain-relieving layer provided on the proximal portion of the inner layer and a restraining member positioned on the distal end of the strain-relieving layer, the restraining member restricting the expansion of at least one adjacent (e.g., lower) portion of the inner layer and the strain-relieving layer. For example, in some implementations, the restraining member restricts the expansion / unfolding of the folded portion, thereby preventing the seam from propagating axially or opening further radially after pre-expansion. In some implementations, the sheath kit system further comprises an expander sized and configured to be received within the lumen of the inner layer, the expander comprising an extended shaft and an expansion element provided thereon. In some implementations, the sheath kit system includes a tray sized and configured to receive a sheath and a dilator, the tray including a release mechanism coupled to a restraining member, the release mechanism holding the restraining member and thereby removing it from the sheath when the sheath is removed from the tray. In some implementations, at least a portion of the sheath (e.g., an inner layer and / or strain-relieving layer) is configured to locally expand from a non-expanded configuration with a lumen having a first diameter to an expanded configuration with a second, larger diameter, and then locally contract at least partially back toward the non-expanded configuration in response to a radially outward force applied to the lumen by the expansion element of the dilator (and / or medical device), as the dilator (and / or medical device) passes through the lumen. In some implementations, a restraining member restricts the expansion of the sheath adjacent to the restraining member (e.g., an inner layer and a strain-relieving layer).

[0084] Further implementations of the present disclosure provide methods for delivering a medical device through a sheath. In some implementations, the method includes providing a radially expandable sheath having a continuous inner layer defining a lumen through which the inner layer includes a proximal portion and a body portion, as well as a folded portion extending along the length of the inner layer. In some implementations, the expandable sheath includes a tubular strain-relieving layer provided on the proximal portion of the inner layer, and a restraining member positioned on the distal end of the strain-relieving layer, the restraining member restricting the expansion of at least one adjacent (e.g., lower) portion of the inner layer and the strain-relieving layer. For example, in some implementations, the restraining member restricts the expansion / unfolding of the folded portion, thereby preventing the seam from propagating axially or opening further radially after pre-expansion. In some implementations, the method further includes removing a dilator received from the lumen of the inner layer, the restraining member restricting the expansion of the sheath (e.g., the inner layer and / or strain-relieving layer) due to a radially outward force applied by the dilator. In some implementations, the method includes removing the restraining member from the sheath. In some implementations, the method includes introducing a medical device into the proximal end of the central lumen of the sheath; advancing the medical device through the proximal portion of the inner layer (e.g., the portion of the sheath corresponding to the strain relief layer), thereby applying a radially outward force to the central lumen (e.g., the inner layer) by the medical device; locally expanding the inner layer and the strain relief layer adjacent to the medical device from a non-expanded configuration to an expanded configuration; and locally contracting the strain relief layer toward the non-expanded configuration as the medical device passes through the corresponding portion of the lumen of the sheath. In some implementations, the method includes advancing the medical device beyond the distal end of the strain relief layer; advancing the medical device through the main body portion of the lumen of the sheath; locally expanding the main body portion of the sheath from a non-expanded configuration to an expanded configuration at a position close to the medical device in response to the radially outward force of the medical device that locally contracts with respect to the inner layer; locally contracting the sheath by at least partially returning it to the non-expanded configuration as the medical device passes through the lumen; and advancing the medical device beyond the distal opening of the sheath.

[0085] In some implementations, at least a portion of the sheath (e.g., an inner layer and / or strain-relieving layer) is configured to locally expand from a non-expandable configuration with a first diameter to an expanded configuration with a second, larger diameter, and then locally contract towards the non-expandable configuration, at least partially, in response to a radially outward force applied to the lumen by the expansion element of the dilator (and / or medical device), as the dilator (and / or medical device) passes through the lumen.

[0086] A further implementation of this disclosure provides a method for inserting a medical device into a patient's blood vessel. In some implementations, the method includes providing a radially expandable sheath having a continuous inner layer defining a lumen through which the inner layer includes a proximal portion and a main portion, as well as a folded portion extending along the length of the inner layer. In some implementations, the expandable sheath includes a tubular strain-relieving layer provided on the proximal portion of the inner layer, and a restraining member positioned on the distal end of the strain-relieving layer, the restraining member restricting the expansion of at least one adjacent (e.g., lower) portion of the inner layer and the strain-relieving layer. For example, in some implementations, the restraining member restricts the expansion / unfolding of the folded portion, thereby preventing the seam from propagating axially or opening further radially after pre-expansion. In some implementations, the method further includes removing a dilator received from the lumen of the inner layer, the restraining member restricting the expansion of the sheath (e.g., the inner layer and / or strain-relieving layer) due to a radially outward force applied by the dilator. In some implementations, the method includes removing the restraining member from the sheath. In some implementations, the method includes inserting the sheath at least partially into the patient's blood vessel and introducing the medical device to the proximal end of the central lumen of the sheath. In some implementations, the method includes advancing the medical device through the proximal portion of the inner layer (e.g., the portion of the sheath corresponding to the strain relief layer), thereby applying a radially outward force by the medical device to the central lumen (e.g., the inner layer), locally expanding the inner layer and the strain relief layer adjacent to the medical device from a non-expanded configuration to an expanded configuration, locally contracting the strain relief layer toward the non-expanded configuration as the medical device passes through the corresponding portion of the lumen of the sheath, and advancing the medical device beyond the distal end of the strain relief layer.In some implementations, the method includes advancing the medical device through the lumen of the main body portion of the sheath; locally expanding the main body portion of the sheath from a non-expanded configuration to an expanded configuration at a position close to the medical device in response to a radially outward force of the medical device being applied to the inner layer; locally contracting the sheath to at least partially return to the non-expanded configuration as the medical device passes through the lumen; and advancing the medical device beyond the distal opening in the sheath to the treatment site in the blood vessel.

[0087] In some implementations, the expander extends the distal end of the strain relaxation layer.

[0088] In some implementations, the inner layer includes at least one folded portion, and the length of the folded portion is at least partially unfolded by locally expanding the lumen of the sheath.

[0089] In some implementations, the sheath further includes an outer layer provided on top of the inner layer, and the outer layer is discontinuous and includes overlapping portions and a base portion.

[0090] In some implementations, when the sheath is in a non-extended configuration, the overlapping portion overlaps with the base portion, which has a folded portion of the inner layer positioned between the overlapping portion and the base portion.

[0091] In some implementations, the strain relaxation layer extends at least partially onto the outer layer.

[0092] In some implementations, the medical device is an artificial device mounted on a delivery device in a radially crimped state.

[0093] In some implementations, advancing the prosthetic device through the lumen of the sheath involves advancing the delivery device and the prosthetic device through the lumen of the sheath into the patient's vascular structure.

[0094] In some implementations, the artificial device includes an artificial heart valve, and the method further includes implanting the artificial heart valve in the patient's treatment site.

[0095] In some implementations, the artificial heart valve is attached to the balloon catheter of the delivery device as the artificial heart valve advances through the sheath.

[0096] In some implementations, the sheath is inserted into the patient's femoral artery.

[0097] The various implementations described above can be combined based on the desired sheath system characteristics. [Brief explanation of the drawing]

[0098] [Figure 1] Figure 1 is an elevation view of an expandable sheath with an intravascular delivery device for implanting artificial implants. [Figure 2] Figure 2 is an elevation view of an expandable sheath, including the introducer locking hub, sheath locking sleeve, and introducer. [Figure 3] Figure 3 is an elevation view of the expandable sheath from Figure 2, combined with an intravascular delivery device for implanting an artificial implant. [Figure 4] Figure 4 is an elevation view of the expandable sheath, sheath hub, introducer locking hub, and sheath locking sleeve shown in Figure 2. [Figure 5A] Figure 5A shows the sheath hub, introducer locking hub, and sheath from Figure 2. [Figure 5B] Figure 5B is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve shown in Figure 2. [Figure 6] Figure 6 is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve shown in Figure 2. [Figure 7] Figure 7 shows the sheath locking sleeve of Figure 2 and the distal end view of the proximal fluid seal of Figures 5A-B. [Figure 8A] Figure 8A is a first elevation view of the introducer locking hub of Figure 2, coupled to the introducer. [Figure 8B] Figure 8B is a second (rotated) elevation view of the introducer locking hub of Figure 2, coupled to the introducer. [Figure 8C] Figure 8C is a distal end view of the introducer locking hub of Figure 2, coupled to the introducer. [Figure 8D] Figure 8D is a partial side view of the introducer locking hub of Figure 2, coupled to the introducer. [Figure 8E] Figure 8E is a partial perspective view of the introducer locking hub of Figure 2, coupled to the introducer. [Figure 8F] Figure 8F is a partial perspective view of the introducer locking hub of Figure 2, coupled to the introducer. [Figure 9A] Figure 9A is a distal end view of the introducer locking hub shown in Figure 2. [Figure 9B] Figure 9B is a first elevation view of the introducer locking hub shown in Figure 2. [Figure 9C] Figure 9C is a proximal end view of the introducer locking hub in Figure 2. [Figure 9D] Figure 9D is a first perspective view of the introducer locking hub in Figure 2. [Figure 9E] Figure 9E is a second elevation view of the introducer locking hub shown in Figure 2. [Figure 9F] Figure 9F is a second perspective view of the introducer locking hub in Figure 2. [Figure 10A] Figure 10A is a distal end view of the sheath locking sleeve shown in Figure 2. [Figure 10B] Figure 10B is a first elevation view of the sheath locking sleeve shown in Figure 2. [Figure 10C] Figure 10C is a proximal end view of the sheath locking sleeve shown in Figure 2. [Figure 10D] Figure 10D is a first perspective view of the sheath locking sleeve shown in Figure 2. [Figure 10E]Figure 10E is a second elevation view of the sheath locking sleeve shown in Figure 2. [Figure 10F] Figure 10F is a second perspective view of the sheath locking sleeve shown in Figure 2. [Figure 11] Figure 11 is a side elevation cross-sectional view of a portion of the expandable sheath shown in Figures 1 and 2. [Figure 12] Figure 12 is a magnified view of a portion of the expandable sheath shown in Figures 1 and 2. [Figure 13A] Figure 13A is a magnified view of a portion of the expandable sheath from Figures 1 and 2, with the outer layer removed for illustrative purposes. [Figure 13B] Figure 13B is an enlarged view of a portion of the braided layer of the sheath shown in Figures 1 and 2. [Figure 14] Figure 14 is a magnified view of a portion of the expandable sheath shown in Figures 1 and 2, illustrating the expansion of the sheath as the artificial device advances through it. [Figure 15] Figure 15 is a side view of the expandable sheath shown in Figures 1 and 2. [Figure 16] Figure 16 is an enlarged cross-sectional view of the sheath of Figure 15 along section line 16-16. [Figure 17] Figure 17 is a cross-sectional view of the non-expanded sheath of Figure 16 along section line 17-17. [Figure 18] Figure 18 is a cross-sectional view of the non-expanded sheath of Figure 15 along section line 18-18. [Figure 19] Figure 19 is a cross-sectional view of the non-expanded sheath of Figure 15 along section line 19-19. [Figure 20] Figure 20 is a cross-sectional view of the expanded sheath of Figure 15 along section line 19-19. [Figure 21] Figure 21 is a side view of the expandable sheath shown in Figures 1 and 2. [Figure 22] Figure 22 is a cross-sectional view of the non-expanded sheath of Figure 21 along section line 22-22. [Figure 23] Figure 23 is a cross-sectional view of the expanded sheath of Figure 21 along section line 22-22. [Figure 24]Figure 24 is a side view of an exemplary sheath system. [Figure 25] Figure 25 is a top view of an exemplary sheath system included in the corresponding package tray. [Modes for carrying out the invention]

[0099] The following description of specific examples of the concept of the present invention should not be used to limit the scope of the claims. Other examples, features, embodiments, implementations, and advantages will be apparent to those skilled in the art from the following description. As will be understood, devices and / or methods may have other different and obvious embodiments without departing in any way from the spirit of the concept of the present invention. Accordingly, the drawings and description should be considered as illustrative and not limiting.

[0100] For the purposes of this Specification, specific aspects, advantages, and novel features of implementations of the Disclosure are described herein. The methods, systems, and apparatus described herein should not be construed as limiting. Rather, this Disclosure covers all novel and non-obvious features and aspects of various disclosed implementations and implementations, both individually and in various combinations and subcombinations. The methods, systems, and apparatus of this Disclosure are not limited to any specific aspect, feature, or combination thereof, and the disclosed methods, systems, and devices do not require that any one or more specific advantages exist or problems are solved.

[0101] Any particular aspect of this disclosure, or any feature, integer, property, compound, chemical part, or group described in conjunction with the examples, is understood to be applicable to any other aspect or example described herein, insofar as it does not conflict with such other aspects or examples. All features disclosed herein (including the appended claims, abstract, and drawings), and / or any methods or steps of a process disclosed herein, can be combined in any combination, except for any combination in which at least some of such features and / or steps are mutually exclusive. This disclosure is not limited to any of the aforementioned implementation details. This disclosure extends to any novel feature, or any novel combination, of the features disclosed herein (including the appended claims, abstract, and drawings), or any novel method or step of a process disclosed herein, or any novel combination.

[0102] Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated herein by reference is incorporated herein, but only to the extent that the incorporated material does not conflict with any existing definitions, statements, or other disclosure material contained herein. For this reason, and to the extent necessary, the disclosure expressly contained herein takes precedence over any conflicting material incorporated herein by reference. Any material, or any part thereof, that is said to be incorporated herein by reference but conflicts with any existing definitions, statements, or other disclosure material contained herein is incorporated only to the extent that no conflict arises between the incorporated material and the existing disclosure material.

[0103] In this specification and in the appended claims, the singular forms “a,” “an,” and “the” include plural nouns unless the context clearly indicates otherwise. Ranges may be expressed herein as values ​​from “about” one particular value to and / or “about” another particular value. Where such ranges are expressed, the other aspects include values ​​from one particular value to and / or the other particular value. Similarly, where values ​​are expressed as approximations, the use of the antecedent “about” will be understood to mean that a particular value forms another aspect. It will be further understood that each endpoint of a range is significant both with respect to and independently of the other endpoints.

[0104] "Optional" or "optional" means that the event or situation described thereafter may or may not occur, and that the description includes instances in which the event or situation occurs, and instances in which it does not occur.

[0105] As used herein, the terms “proximal” and “distal” refer to regions of the sheath, catheter, or delivery assembly. “Proximal” means the region closest to the device handle, while “distal” means the region furthest from the device handle.

[0106] As used herein, “axial” or “axial direction” refers to the direction along the longitudinal axis of the sheath.

[0107] Throughout this description and the claims, the word “comprise,” and its variations such as “comprising” and “comprises,” means “including, but not limited to,” and is not intended to exclude, for example, other adducts, components, integers, or steps. “Exemplary” means “an example of,” and is not intended to suggest a preferred or ideal embodiment. “Etc.” is used for illustrative purposes only and not in a restrictive sense.

[0108] The disclosed implementation of the expandable sheath allows for the temporary expansion of a portion of the introducer sheath to accommodate the delivery system, and then returns to its original diameter as the device passes, thereby minimizing trauma to the vessel. The disclosed implementation of the introducer sheath prevents the introducer from separating from the sheath during insertion by locking the proximal hub of the introducer to the proximal hub of the sheath. By fixing the introducer and sheath, the introducer is prevented from moving backward during insertion, thereby maintaining a firm fit and smooth transition between the introducer and the distal end of the sheath. Furthermore, the current implementation can reduce the time required for the procedure and can reduce the risk of longitudinal or radial vascular tearing or plaque dislodgement because only one sheath is required instead of several different sized sheaths. This expandable sheath implementation can avoid the need for multiple insertions for vessel dilation.

[0109] Examples of expandable introducer sheaths are disclosed, for example, U.S. Patent No. 8,690,936, "Expandable Sheath for Introducing an Endovascular Delivery Device into a Body", U.S. Patent No. 8,790,387, "Expandable Sheath for Introducing an Endovascular Delivery Device into a Body", U.S. Patent No. 10,639,152, "Expandable Sheath and Methods of Using the Same", U.S. Patent No. 10,792,471, "Expandable Sheath", U.S. Patent Application No. 16 / 407,057, "Expandable Sheath with Elastomeric Cross Sectional Portions", U.S. Patent No. 10,327,896, "Expandable Sheath with Elastomeric Cross Sectional Portions", U.S. Patent No. 11,273,062, "Expandable Sheath", and Application No. PCT / US2021 / 019514, "Expandable sheath for introducing an endovascular delivery device "into a body", application number PCT / US2021 / 031227 "Expandable sheath for introducing an endovascular delivery device into a body", application number PCT / US2021 / 031275 "Expandable sheath for introducing an endovascular delivery device into a body", US Patent Application No. 17 / 113,268 "Expandable Sheath and Method of Using the Same", application number PCT / US2021 / 058247 "Self-Expanding,"Two Component Sheath", application number PCT / US2022 / 012785 "Expandable Sheath", U.S. Patent No. 11,051,939 "Active Introducer Sheath System", application number PCT / US2022 / 012684 "Introducer with Sheath Tip Expander", U.S. Patent Application No. 17 / 078,556 "Advanced Sheath Patterns", application number PCT / US2021 / 025038 "Low temperature hydrophilic adhesive for use in expandable sheath for introducing an endovascular delivery device into a body", application number PCT / US2021 / 050006 "Expandable Sheath Including Reversible Bayonet Locking Hub", U.S. Provisional Patent Application No. 63 / 280,251 "Expandable Sheath Gasket to Provide There are U.S. Provisional Patent Application No. 63 / 530,144, “Introducer / Dilator with Folded Balloon,” and U.S. Provisional Patent Application No. 63 / 502,907, “Lead Screw Driven Sheath Dilator,” the disclosures of which are incorporated herein by reference.

[0110] The stretched introducer sheaths disclosed herein are particularly suitable for the 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 herein. Examples of such implantable heart valves are described in U.S. Patents 5,411,552 and 9,393,110, both of which are incorporated herein by reference. The expandable introducer sheaths disclosed herein may also be used to deliver other types of implantable medical devices, such as self-expanding and mechanically expandable implantable heart valves, stents, or filters. Beyond transcatheter heart valves, introducer sheath systems may be useful in other types of minimally invasive surgical procedures, such as surgical procedures requiring the introduction of a device into a target blood vessel. For example, introducer sheath systems can be used to introduce other types of delivery devices for placing various types of endovascular devices (e.g., stents, stent grafts, balloon catheters for angioplasty procedures, etc.) into many types of blood vessels and non-vascular body lumens (e.g., veins, arteries, esophagus, bile 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. Diagnostic devices, for example, can be implantable.

[0111] Figure 1 shows an exemplary sheath 8 used with a typical delivery device 10 for delivering an implant 12 or other type of implantable device (e.g., a tissue heart valve) to a patient. The delivery device 10 may 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 nose catheter 15 extending through the balloon catheter 16. The guide catheter 14, balloon catheter 16, and nose catheter 15 in the illustrated example are fitted to slide longitudinally relative to each other to facilitate the delivery and positioning of the implant 12 at the implantation site in the patient's body, as will be described in detail below. However, the sheath 8 is intended to be used with any type of extended delivery device used for implanting balloon-inflatable prosthetic valves, self-expanding prosthetic valves, and other prosthetic devices.

[0112] As described in more detail herein, generally, the sheath 8 includes an elongated, expandable tube that, at the time of use, is inserted into a blood vessel (e.g., transfemoral vessel, femoral artery, iliac artery) by passing through the patient's skin, so that the distal end of the sheath 8 is inserted into the blood vessel. The sheath 8 includes, for example, a hemostatic valve and / or sealing feature at the proximal end of the sheath, within the sheath hub 20, to provide hemostasis and prevent blood leakage from the patient through the sheath 8. The sheath 8, including the introducer 6, advances into the patient's vascular structure. Once the positioned introducer 6 is removed, the delivery device 10 is inserted into / through the sheath 8, and then the artificial device (implant 12) is delivered and implanted within the patient.

[0113] As provided in Figures 2 and 3, the introducer device / sheath assembly may include a sheath hub 20 at the proximal end of the device and an expandable sheath 8 extending distally from the sheath hub 20. The sheath 8 is coupled to the sheath hub 20, which is then detachably coupled to an optional sheath locking system 18. The sheath locking system 18 allows the introducer 6, or any other desired device, to be detachably coupled (axially and rotatably) to the sheath 8.

[0114] As shown in Figures 2–6, the sheath hub 20 can optionally function as a handle for the device. The sheath hub 20 provides housing for the required sealing assembly and access points for secondary lumens (e.g., fluid lumens) that are in fluid communication with the central lumen of the sheath hub 20. In some examples, as described herein and as shown in Figures 5A, 5B, and 7, the sealing assembly 24 is included in the sheath hub 20. The sealing assembly 24 includes a proximal seal 24a, an intermediate seal 24b, and a distal seal 24c. When assembled, the introducer 6 passes through the sealing assembly and extends distally to the sheath 8. The proximal seal 24a, intermediate seal 24b, and distal seal 24c are each formed to prevent unwanted fluid from advancing proximal to the sheath hub 20 and the sealing assembly 24. Each seal is openable and closable and provides pressure fluctuations to influence the desired fluid flow from a physician or technician.

[0115] In some implementations, the distal end of the sheath hub 20 includes a thread 21 for coupling to a threaded sheath hub cap 22. The sheath 8 is provided between the sheath hub 20 and the sheath hub cap 22 so as to couple the sheath hub cap 22 to the sheath hub 20 and secure the sheath 8 to the sheath hub 20. The sheath hub cap 22 is a cylindrical cap having a cap body with a proximal end and a distal end, defining a central lumen that extends longitudinally between the proximal and distal ends. The sheath hub cap 22 has a larger diameter at its proximal end than at its distal end.

[0116] In some implementations, the sheath hub 20 further includes receiving a slot 48 for coupling a sheath locking system 18, in particular, a locking sleeve 28, to the sheath hub 20. In some implementations, the exemplary receiving slot 48 includes an opening that extends around a portion of the diameter of the sheath hub 20 and is sized and configured to receive the interference diameter 66 of the locking sleeve 28. The coupling between the receiving slot 48 and the interference diameter 66 fixes the locking sleeve 28 and the sheath hub 20 axially and rotationally relative to each other.

[0117] Figure 2 shows the sheath 8 of Figure 1, optionally including a sheath locking system 18 that prevents axial and rotational movement of the introducer 6 relative to the sheath 8. An exemplary locking system is disclosed in PCT / US2021 / 050006, “Expandable Sheath Including Reverse Bayonet Locking Hub,” which is incorporated herein by reference. The locking system 18 disclosed herein is also intended to be optionally used to connect the sheath 8 / sheath hub 20 with other delivery system components, catheters, dilators, etc., which have the same mating features.

[0118] As described herein, in some implementations, the sheath locking system 18 is used to secure the introducer 6 to the sheath 8 during insertion without requiring a physician or technician to hold the introducer 6 and sheath 8 in place at the distal end. As shown in Figures 8A–8B, the sheath locking system 18 includes a locking sleeve 28 and an introducer locking hub 30 (containing the corresponding introducer 6). In some implementations, the locking sleeve 28 is coupled to the sheath 8 via the sheath hub 20. The locking sleeve 28 engages with the introducer locking hub 30 and is movable between a locked position and an unlocked position, thereby fixing the positions of the introducer 6 and sheath 8 and preventing movement between them, in particular during insertion into a patient. As will be described in more detail below, the sheath locking system 18 may be used to keep the introducer 6 from separating from the sheath 8 and to prevent the formation of gaps between the introducer 6 and the sheath 8 that could cause patient abrasions and unintended fluid flow during insertion.

[0119] Figures 2, 5A–5B, and 6 show a sheath locking sleeve 28 coupled to an introducer locking hub 30 and a sheath hub 20. In some implementations, as will be described in more detail below, the locking sleeve 28 includes a guide 31 that engages with a locking channel 38 provided on the introducer locking hub 30. The guide 31 moves within the locking channel 38 between an unlocked position in which the sheath locking sleeve 28 is rotatable and axially movable relative to the introducer locking hub 30, and a locked position (shown in Figure 2) in which the locking sleeve 28 is axially fixed relative to the introducer locking hub 30.

[0120] The locking sleeve 28 is shown, for example, in Figures 10A–10F. The locking sleeve 28 includes an elongated sleeve body 29 having a central lumen 56 that extends longitudinally between the proximal end 58 and distal end 60 of the sleeve body 29. A cross-sectional view of the sheath locking system 18 is provided, as shown in Figure 6, where the central lumen 56 defines the substantially cylindrical inner surface 62 of the sheath locking sleeve 28. In some implementations, the central lumen 56 has a diameter of at least 0.3 inches. In some examples, the diameter is in the range of 0.3 inches to 0.6 inches. Preferably, the diameter is about 0.40 inches. The distal end 60 of the sleeve body 29 optionally has a frustoconical outer surface 64 that tapers around the distal end 60 to help position the locking sleeve 28 within the sheath hub 20 and abut against the sealing assembly 24 (as shown in Figures 5A and 5B). In some implementations, the locking sleeve 28 also has multiple interference diameters 66 that extend radially from the outer surface of the sleeve body 29 around all or part of the circumference of the locking sleeve 28. As shown in Figures 5A and 6, the distally positioned interference diameters 66 are sized and configured to engage with corresponding recesses and / or slots 48 provided within the sheath hub 20 to secure the locking sleeve 28 to the sheath hub 20. In some implementations, as shown in Figure 6, the proximally positioned interference diameters 66 optionally seat against the proximal end of the sheath hub 20.

[0121] As shown in Figure 10B, the locking sleeve 28 includes a guide 31 protruding from the outer surface 68 of the locking sleeve 28. As described herein, as shown in Figure 9B, the guide 31 is sized and configured to engage with a locking channel 38 of a corresponding shape within the introducer locking hub 30. The guide 31 extends at least partially radially from the outer surface 68 and around the outer periphery of the outer surface 68. As provided in Figure 6, in some implementations, when the locking sleeve 28 and the introducer locking hub 30 are coupled, the upper surface of the guide 31 does not extend beyond the outer surface of the introducer locking hub 30. For example, the height of the guide 31 may optionally be sized to correspond to the wall thickness of the introducer locking hub 30 adjacent to the guide when the sheath locking sleeve 28 and the introducer locking hub 30 are coupled. In another example, the top surface of the guide 31 may optionally be recessed relative to the outer surface of the introducer locking hub 30; that is, the height of the guide 31 is less than the wall thickness of the introducer locking hub 30. In yet another example, the height of the guide 31 may optionally be greater than the wall thickness of the introducer locking hub 30, such that the top surface of the guide 31 extends beyond the outer surface of the introducer locking hub 30 when the sheath locking sleeve 28 and the introducer locking hub 30 are coupled. In some examples, the height / axial length of the guide 31 is approximately 0.050 inches to approximately 0.10 inches. In some examples, the height / axial length of the guide 31 is approximately 0.075 inches.

[0122] As shown in Figures 10D to 10F, the guide 31 is optionally defined as a cylindrical projection. However, the guide 31 is intended to have any other regular or irregular shape that facilitates the movement of the guide 31 within the locking channel 38 of the introducer locking hub 30. For example, the guide 31 may optionally have an elongated hexagonal shape. The guide 31 may have a diameter / width in the range of about 0.05 inches to about 0.20 inches. Preferably, the guide 31 has a diameter / width of about 0.100 inches.

[0123] Generally, the locking sleeve 28 may be optionally formed from polycarbonate. In other implementations, the locking sleeve 28 may be formed from rigid plastic or any other material suitable for providing a strong locking connector for the introducer 6, including, for example, metal, composite material, or other suitable material.

[0124] Figures 2–6 show the introducer locking hub 30 coupled to the locking sleeve 28. Figures 8A–8F show the introducer locking hub 30 coupled to the introducer 6. Figures 9A–9F provide multiple diagrams of the introducer locking hub 30. As described herein, the introducer 6 may be fixedly coupled to the introducer locking hub 30. For example, in some implementations, the introducer locking hub 30 is coupled to the locking sleeve 28 to fix the position of the introducer 6 (axially and rotationally) relative to the locking sleeve 28 / sheath 8. The introducer 6 and the introducer locking hub 30 are each described in more detail herein.

[0125] Figures 8A–8F show an introducer locking hub 30 having an exemplary introducer 6 coupled to the introducer locking hub 30. As provided in the cross-sectional views of Figures 5A and 5B, the introducer 6 is coupled to the introducer locking hub 30 and extends beyond the distal end of the introducer locking hub 30 body. When coupled to the sheath hub 20, the introducer 6 extends through the central lumen 56 of the sheath locking sleeve 28, the sheath hub 20, and the central lumen of the sheath 8. As described herein, the sheath 8 generally comprises a radially expandable tubular structure. The passage of the introducer 6 through the sheath 8, positioned within the patient's vascular structure, expands the sheath 8, resulting in a corresponding radial expansion of the vessel to the approximate diameter of the sheath 8. In other words, the diameter of the central lumen of the sheath 8 generally corresponds to the outer diameter of the introducer 6, so that the introducer 6 expands / pre-dilates the patient's blood vessels to provide a mechanism for receiving the medical device / implant 12.

[0126] As provided in Figures 8A–8F, the introducer 6 is formed as an extended body and optionally includes a central lumen extending through it. When assembled, as shown in Figures 5A and 5B, the central lumen of the introducer 6 aligns with the central lumen of the introducer locking hub 30, the sheath hub 20, and the sheath 8. In some implementations, as provided in Figures 5A and 5B, the introducer 6 is received within a recessed opening 39 provided on the inner surface of the introducer locking hub 30, and the recessed opening 39 axially aligns with the central lumen 45 of the introducer locking hub 30. In some implementations, the introducer 6 is fixedly or releasably coupled to the introducer locking hub 30 at the recessed opening 39. In some examples, the introducer 6 is fixedly coupled to the introducer locking hub 30 at the recessed opening 39. In some implementations, the introducer 6 has a diameter equivalent to or smaller than the diameter of the recessed opening 39. For example, the introducer 6 is coupled to the recessed opening 39 of the introducer locking hub 30 by at least one of press fitting, interference fitting, snap fitting, mechanical fasteners, chemical fasteners (e.g., adhesives), welding, thermal processes, and / or any other suitable bonding processes known in the art.

[0127] As described herein, the introducer 6 optionally has a central lumen that aligns with the central lumen 45 of the introducer locking hub 30. When joined, this joined lumen allows surgical instruments and / or medical devices (e.g., guidewires) to pass to the treatment site. In the exemplary system, as provided in Figures 5A and 5B, the central lumen of the introducer 6 has a diameter corresponding to at least a portion of the diameter of the central lumen 45 of the introducer locking hub 30. Generally, the corresponding diameter portion is adjacent to the distal end of the central lumen 45. In other examples, the diameter of the central lumen 45 at the distal end of the introducer locking hub 30 is slightly larger than the diameter of the central lumen passing through the introducer 6. The central lumen 45 may also optionally define a decreasing tapered portion 41 extending between the proximal and distal ends of the introducer locking hub 30, as shown in Figure 6. The corresponding diameter portion and the decreasing tapered portion 41 allow for the smooth transition and delivery of surgical instruments and / or medical devices into the central lumen of the introducer 6 through the introducer locking hub 30.

[0128] As shown in Figures 9A–9F, the introducer locking hub 30 includes a hub body 32 having a proximal end 70 and a distal end 72, and optionally defining a central lumen 45 extending through it. The hub body 32 has a first (central) portion 33, a second (distal) portion 35 extending distally from the first portion 33, and a third (proximal) portion 37 extending proximal from the first portion 33. The first portion 33 may optionally include a cylindrical recessed opening 39 for receiving and holding the introducer 6 and its outer surface 43. In some examples, the recessed opening 39 has a diameter ranging from 0.15 inches to about 0.25 inches. In some examples, the recessed opening 39 has a diameter ranging from 0.17 inches to about 0.20 inches. In some examples, the recessed opening has a diameter of about 0.194 inches.

[0129] In some implementations, the third (proximal) portion 37 of the introducer locking hub 30 includes a tapering portion 41 of the central lumen 45. As shown in Figure 6, the tapering portion 41 defines a frustoconical shape in which the taper / diameter decreases in the direction extending from the proximal end to the distal end of the sheath 8. The tapering portion 41 is intended to have a minimum diameter of approximately 0.007 inches and a maximum diameter of approximately 0.194 inches.

[0130] As shown in Figures 5A and 5B, when coupled, the central lumen 56 of the locking sleeve 28 aligns with the central lumen 45 of the introducer locking hub 30. In some examples, the central lumen 56 of the locking sleeve 28 is coaxial with the central lumen 45 of the introducer locking hub 30. When coupled, the proximal end of the locking sleeve 28 is received within the central lumen 45 of the introducer locking hub 30. Thus, in some implementations, the proximal end surface of the locking sleeve 28 is positioned adjacent to the shoulder 50, which is provided on the inner surface of the central lumen 45 of the introducer locking hub 30. As shown in Figures 5A and 5B, the central lumen 45 of the introducer locking hub 30 includes a first portion 52 and a second portion 54. The first portion 52 is positioned adjacent to the proximal end of the introducer locking hub 30 and defines the first diameter, and the second portion 54 is positioned adjacent to the distal end of the introducer locking hub 30 and defines the second, larger diameter. The recessed opening 39 of the introducer locking hub 30 may optionally be a component of the first portion 52 of the central lumen 45, or a separate component of the central lumen 45 located between the first (proximal) portion 52 and the second (distal) portion 54. When the locking sleeve 28 and the introducer locking hub 30 are joined, at least a portion of the sleeve body 29 of the sheath locking sleeve 28 is received within the second portion 54 (the larger diameter portion) of the central lumen 45 of the introducer locking hub 30. In some implementations, the central lumen 56 of the sheath locking sleeve 28 is aligned with the central lumen 45 of the introducer locking hub 30 so that they are coaxial and form a smooth inner surface along the combined central lumen of the introducer locking hub 30 and the sheath locking sleeve 28.

[0131] As described herein, the locking sleeve 28 is coupled to the introducer locking hub 30 via an engagement between a guide 31 provided on the locking sleeve 28 and a locking channel 38 provided within the introducer locking hub 30. As shown in Figures 9A–9F, the introducer locking hub 30 optionally includes two locking channels 38. However, the introducer locking hub 30 is intended to include one locking channel 38 or three or more locking channels 38. The locking channel 38 may optionally form a recess or groove on the surface of the introducer locking hub 30, as any other feature that can receive a slot opening, clip, or guide 31 / locking sleeve 28 and secure it to the introducer locking hub 30. As shown in Figure 9B, the locking channel 38 provides an interface for fixing the sheath locking sleeve 28 to the introducer locking hub 30 and ensuring a fixed axial position between the introducer 6 and the sheath 8.

[0132] As shown in Figure 9B, the locking channel 38 is formed on or proximal to the distal end of the introducer locking hub 30. In some implementations, the locking channel 38 includes an opening on the distal end surface of the introducer locking hub 30. The opening of the locking channel 38 extends to an angled guide portion 40 that transitions into / extends to a locking portion 42. In some implementations, the guide portion 40 is configured to orient the guide 31 provided on the locking sleeve 28 toward the locking portion 42 axially and / or circumferentially along the sidewall of the guide portion 40 when the introducer locking hub 30 and / or the sheath locking sleeve 28 rotates. In some implementations, the locking portion 42 is configured to reliably engage with the guide 31, fixing the axial position of the introducer locking hub 30 relative to the sheath locking sleeve 28. As shown in Figure 9B, the guide portion 40 of the locking channel 38 extends axially from the distal end of the introducer locking hub 30 toward the proximal end of the introducer locking hub 30, and circumferentially around the introducer locking hub 30. For example, in some implementations, the guide portion 40 of the locking channel 38 may be described as extending helically around / along the length of the introducer locking hub 30, or at an angle from the distal end of the introducer locking hub 30.

[0133] As shown in Figures 9B and 9D, the locking portion 42 of the locking channel 38 extends from the end of the guide portion 40. In some implementations, the locking portion 42 extends from the end of the guide portion 40 at a certain angle. As provided in Figure 9B, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is greater than 90 degrees. In another example, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is about 120 degrees. In the exemplary system, the locking portion 42 extends around a portion of the circumference of the introducer locking hub 30. The locking portion 42 may optionally extend generally parallel to the distal end face of the introducer locking hub 30. In some implementations, the locking portion 42 may optionally extend circumferentially around the introducer locking hub 30 in a direction substantially perpendicular to the longitudinal axis of the introducer locking hub 30 and / or the introducer 6. In the exemplary system, the length of the guide portion 40 (measured along its centerline) is greater than the length of the locking portion 42 (measured along its centerline). In another example, the length of the guide portion 40 is equal to or less than the length of the locking portion 42.

[0134] The locking portion 42 may optionally include a catch 44 for securing the guide 31 within the locking portion 42 of the locking channel 38 and forming a partial barrier that holds the guide 31 within the locking portion 42. As shown in Figure 9B, the catch 44 includes a projection extending from the side wall 74 of the locking portion 42 and sized and configured to removably secure the guide 31 within the locking channel 38. In some implementations, the catch 44 extends proximal from the side wall 42a of the locking portion 42 toward the centerline of the locking portion 42 and has sufficient height to hold the guide 31 between the catch 44 and the end of the locking portion 42.

[0135] In some implementations, the distal end face 72 of the introducer locking hub 30 may optionally include features for biasing the guide 31 toward and / or into the locking channel 38. For example, in some implementations, the distal end of the introducer locking hub 30 may include an angled tapered surface toward the opening of the locking channel 38. For example, as shown in Figure 9B, the distal end 72 of the introducer locking hub 30 includes a first tapered surface 76 angled toward the leading edge of the opening of the locking channel 38 and a second tapered surface 78 angled toward the trailing edge of the opening of the locking channel 38. The angles of the first tapered surface 76 and the second tapered surface 78 help to bias the guide 31 proximal and into the locking channel 38.

[0136] During use, the engagement between the guide 31 of the locking channel 38 and the guide portion 40 is configured to bias the locking sleeve 28 proximal toward the proximal end 70 of the introducer locking hub 30 (towards the locked position) when the sheath locking sleeve 28 rotates in the first axial direction. In this direction, the guide 31 advances toward the locking portion 42 of the locking channel 38 to the locked position. Alternatively, when the sheath locking sleeve 28 rotates in the second (opposite) axial direction, the engagement between the guide 31 and the locking portion 42 of the locking channel 38 is configured to bias the locking sleeve 28 distally toward the distal end of the introducer locking hub 30 (towards the unlocked position). In the second direction, the guide 31 moves away from the locking portion 42 of the locking channel 38 to / towards the unlocked position. For example, when the guide 31 is in the locked position and held within the locking portion 42 by the catch 44, rotation in a second direction biases the guide 31 against the catch 44, overcoming the opposing force of the catch 44. Further rotation in the second direction moves the guide 31 beyond the catch 44, through the guide portion 40, from the locked position to the unlocked position.

[0137] As shown in Figures 8A–9F, the outer surface of the introducer locking hub body 32 optionally includes gripping features and / or surfaces for use by a physician or technician when operating the introducer locking hub 30. As provided in Figure 9B, the introducer locking hub body 32 may optionally include two recessed gripping surfaces 34 on both sides of the longitudinal axis of the introducer locking hub 30. In some implementations, when the introducer locking hub 30 is viewed from the side, the gripping surfaces 34 define the dogbone / barbell shape of the hub body 32, i.e., a shape having a central portion with a smaller diameter / width and end portions with a larger diameter / width. In an exemplary system, the gripping surfaces 34 are optionally provided along at least 40% of the length of the introducer locking hub body 32. In another example, the gripping surfaces 34 are provided along at least 50% of the length of the introducer locking hub body 32.

[0138] Generally, the introducer locking hub 30 may be formed from polycarbonate. In other implementations, the introducer locking hub 30 may be formed from rigid plastic, or any other material suitable for providing a locking mechanism for the introducer 6, including, for example, metal, composite material, or other suitable material.

[0139] As described herein, the introducer device / sheath assembly includes an expandable sheath 8 extending distally from the sheath hub 20. The expandable sheath 8 has a central lumen that guides the passage of the delivery device 10 for the medical device / implant 12 (artificial heart valve). In some implementations, the introducer device / sheath assembly does not need to include the sheath hub 20. For example, the sheath 8 may be an integrated part of a component of the sheath assembly, such as a guide catheter.

[0140] As described herein, the expandable sheath 8 may have a natural, non-expandable outer diameter that expands locally upon passage of a medical device. For example, the expandable sheath 8 may be formed from a highly elastic material, such that vasodilation is performed by the passing prosthetic device.

[0141] In some implementations, the expandable sheath 8 may include multiple coaxial layers extending along at least a portion of the length of the sheath 8. The structure of the coaxial layers is described in more detail below with respect to Figures 11–23. Exemplary expandable sheaths including coaxial layers are described, for example, in U.S. Patent Application No. 16 / 378,417, entitled “Expandable Sheath”, and U.S. Patent Application No. 17 / 716,882, entitled “Expandable Sheath”, the disclosures of which are incorporated herein by reference.

[0142] Various implementations of the coaxial layered structure of the sheath 8 are described herein. For example, referring to the exemplary sheath 8 shown in Figures 11–14, the expandable sheath 8 may include several layers, including an inner layer 102 (also called the inner layer) and a second layer 104 positioned around the inner layer 102 and radially outward. In some implementations, the sheath 8 includes a third layer 106 positioned around the second layer 104 and radially outward, and a fourth outer layer 108 (also called the outer layer) positioned around the third layer 106 and radially outward. In the illustrated configuration, the inner layer 102 defines the lumen 112 of the sheath extending along the central axis 114, through which a delivery device can travel within the patient's blood vessels to deliver, remove, repair, and / or replace an artificial device moving in a direction along the longitudinal axis of the sheath 8.

[0143] Referring to Figure 12, when the sheath 8 is in a non-expanded state, the various layers of the sheath, e.g., the inner layer 102 and / or the outer layer 108, may optionally form longitudinally extending folds or creases such that the surface of the sheath includes a plurality of ridges 126 (also referred herein as “folds”). The ridges 126 may be spaced circumferentially apart from each other by longitudinally extending valleys 128. When the sheath 8 expands beyond its original diameter D1, as further described herein, the surface expands radially, and as the circumference of the sheath 8 increases, the ridges 126 and valleys 128 may become horizontal or incorporated. When the sheath 8 folds back to its original diameter, the ridges 126 and valleys 128 may be reformed.

[0144] In some implementations, the inner layer 102 and / or the outer layer 108 may include relatively thin layers of polymer material. For example, in some implementations, the thickness of the inner layer 102 may be 0.01mm to 0.5mm, 0.02mm to 0.4mm, or 0.03mm to 0.25mm. In some implementations, the thickness of the outer layer 108 may be 0.01mm to 0.5mm, 0.02mm to 0.4mm, or 0.03mm to 0.25mm.

[0145] In some examples, the inner layer 102 and / or the outer layer 108 may include lubricating, low-friction, and / or relatively inelastic materials. In certain implementations, the inner layer 102 and / or the outer layer 108 may include polymer materials having an elastic modulus of 400 MPa or greater. Exemplary materials may include ultra-high molecular weight polyethylene (UHMWPE) (e.g., Dyneema®), high molecular weight polyethylene (HMWPE), or polyether ether ketone (PEEK). With respect to the inner layer 102 in particular, materials with such a low coefficient of friction can facilitate the passage of artificial devices through the lumen 112. Other suitable materials for the inner layer 102 and the outer layer 108 may include polyimide, polytetrafluoroethylene (PTFE), stretched polytetrafluoroethylene (ePTFE), ethylene tetrafluoroethylene (ETFE), nylon, polyethylene, polyamide, polyether block amide (e.g., Pebax), and / or any combination of the above. Some implementations of the sheath 8 may optionally include a lubricating liner on the inner surface of the inner layer 102. Examples of suitable lubricating liners include materials that can further reduce the coefficient of friction of the inner layer 102, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for the lubricating liner may also include other materials having a coefficient of friction of 0.1 or less, preferably.

[0146] Furthermore, some implementations of Sheath 8 may optionally include an external hydrophilic coating on the outer surface of the outer layer 108. Such a hydrophilic coating may facilitate the insertion of Sheath 8 into the patient's blood vessels and reduce potential damage. Examples of suitable hydrophilic coatings include Harmony® Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings, available from SurModics, Inc., Eden Prairie, Minnesota. DSM Medical Coatings (available from Koninklijke DSM NV, Heerlen, Netherlands) and other hydrophilic coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride) are also suitable for use with Sheath 8. Such hydrophilic coatings may also be included on the inner surface of the inner layer 102 to reduce friction between Sheath 8 and the delivery system, thereby facilitating use and improving safety. In some implementations, hydrophobic coatings such as perylene may be used on the outer surface of the outer layer 108 or on the inner surface of the inner layer 102 to reduce friction.

[0147] In some implementations, the second layer 104 may be a braided layer. Figures 13A and 13B show the sheath 8 with the outer layer 108 removed, exposing the elastic third layer 106. Referring to Figures 13A and 13B, the braided second layer 104 may include multiple members or filaments 110 (e.g., metal, or synthetic wire, or fiber) braided together. The braided second layer 104 may have any desired number of filaments 110, which may be oriented together and braided along any preferred number of axes. For example, referring to Figure 13B, the filaments 110 may include a first set of filaments 110A oriented parallel to a first axis A, and a second set of filaments 110B oriented parallel to a second axis B. A first set of filaments 110A and a second set of filaments 110B can be braided together in a biaxial braid such that the filaments 110A, oriented along axis A, and the filaments 110B, oriented along axis B, form an angle θ. In some implementations, the angle θ can be 5° to 70°, 10° to 60°, 10° to 50°, or 10° to 45°. In the example shown, the angle θ is 45°. In other implementations, the filaments 110 can also be oriented along three axes and braided into a triaxial braid, or oriented along any number of axes and braided into any preferred braid pattern. The second braid layer 104 can extend along the substantial total length L of the sheath 8, or only along a portion of the length of the sheath. In certain implementations, the filaments 110 can be wires made from either metal (e.g., Nitinol, stainless steel, etc.) or various polymers or polymer composite materials, such as carbon fiber. In some implementations, the filament 110 may be circular and have a diameter of 0.01mm to 0.5mm, 0.03mm to 0.4mm, or 0.05mm to 0.25mm. In other implementations, the filament 110 may have a flat cross-section with dimensions of 0.01mm × 0.01mm to 0.5mm × 0.5mm, or 0.05mm × 0.05mm to 0.25mm × 0.25mm. In one embodiment, the filament 110 with a flat cross-section may have dimensions of 0.1mm × 0.2mm. However, other shapes and sizes are also suitable for some implementations.When braided wire is used, the braid density can be optionally varied along the length of the sheath 8. Some implementations have braid densities of 10 picks per inch to 80 picks per inch and may include 8 wires, 16 wires, or up to 52 wires in various braid patterns. In other implementations, the second layer 104 may be laser-cut from a tube or laser-cut, embossed, punched, etc. from a sheet material and rolled into a tubular structure. The second layer 104 may also be woven or braided as desired.

[0148] The third layer 106 may be a stretchable, elastic layer (also referred to as an elastic material layer). In some implementations, the elastic third layer 106 may be configured to apply a radially inward force (e.g., toward the central axis 114 of the sheath) to the underlying layers 102 and 104 as the sheath 8 expands beyond its original diameter as the delivery device passes through it. In other words, the elastic third layer 106 may be configured to apply an annular / radially inward pressure to the layers of the sheath 8 beneath the elastic third layer 106 (e.g., layers 102 and 104) to counteract the expansion of the sheath 8. The radially inward force is sufficient to fold the sheath 8 radially after the delivery device has passed through it, returning it to its unexpanded state.

[0149] In some implementations, the elastic third layer 106 may optionally include one or more members configured as strands, ribbons, or bands 116 helically wound around the braided second layer 104. For example, in the shown embodiment, the elastic third layer 106 includes two elastic bands 116A and 116B wound in opposite helices around the braided second layer 104, but the elastic third layer 106 may include any number of bands depending on the desired properties. The elastic bands 116A and 116B may be made from any of a variety of natural or synthetic elastomers, including silicone rubber, natural rubber, various thermoplastic elastomers, polyurethane, for example, polyurethane siloxane copolymer, urethane, plasticized polyvinyl chloride (PVC), styrene block copolymer, and polyolefin elastomer. In some implementations, the elastic third layer 106 may include an elastomer material having an elastic modulus of 200 MPa or less. In some implementations, the elastic third layer 106 may contain a material exhibiting a fracture elongation of 200% or more, or 400% or more. The elastic third layer 106 may also take other forms, such as a tubular layer containing an elastomer material, a mesh, or a shrinkable polymer layer such as a heat-shrinkable tube layer. Instead of, or in addition to, the elastic third layer 106, the sheath 8 may also contain an elastomer or heat-shrinkable tube layer around the outer layer 108. Examples of such elastomer layers are disclosed in U.S. Publication No. 2014 / 0379067, U.S. Publication No. 2016 / 0296730, and U.S. Publication No. 2018 / 0008407, which are incorporated herein by reference. In other implementations, the elastic third layer 106 may also be radially outward of the polymer outer layer 108.

[0150] In some implementations, one or both of the inner layer 102 and / or the outer layer 108 may be configured to resist axial stretching of the sheath 8 as the sheath 8 expands. More specifically, one or both of the inner layer 102 and / or the outer layer 108 may resist stretching due to longitudinal forces caused by friction between the artificial device and the inner surface of the sheath 8 as the sheath 8 expands and contracts, such that the length L remains substantially constant. With reference to the length L of the sheath 8, as used herein, the term “substantially constant” means that the length L of the sheath 8 increases by 1% or less, 5% or less, 10% or less, 15% or less, or 20% or less. On the other hand, with reference to Figure 13B, the filaments 110A and 110B of the second braided layer 104 may be able to move angularly relative to each other such that the angle θ changes as the sheath 8 expands and contracts. This, combined with the longitudinal folds / ridges 126 of the inner layer 102 and the outer layer 108, may allow the lumen 112 of the sheath 8 to expand as the artificial device / implant 12 advances through it.

[0151] In some implementations, the inner layer 102 and the outer layer 108 may be thermally bonded during the manufacturing process such that the braided second layer 104 and the elastic third layer 106 are encapsulated between layers 102 and the outer layer 108. More specifically, in some implementations, the inner layer 102 and the outer layer 108 may be bonded to each other through the spaces between the filaments 110 in the braided second layer 104 and / or the spaces between the elastic bands 116. Layers 102 and the outer layer 108 may also be joined or bonded together at the proximal and / or distal ends of the sheath 8. In some implementations, layers 102 and the outer layer 108 are not bonded to the filaments 110. This allows the filaments 110 to move angularly relative to each other and to layers 102 and the outer layer 108, which may allow the diameter of the braided second layer 104, and thus the diameter of the sheath 8, to be increased or decreased. When the angle θ between filaments 110A and 110B changes, the length of the second braided layer 104 may also change. For example, when the angle θ increases, the second braided layer 104 can be shortened, and when the angle θ decreases, the second braided layer 104 can be stretched to an acceptable extent by the region to which layers 102 and the outer layer 108 are joined. However, since the second braided layer 104 is not bonded to layers 102 and the outer layer 108, the change in the length of the braided layer due to the change in the angle θ between filaments 110A and 110B does not result in a significant change in the length L of the sheath 8.

[0152] Figure 14 shows the radial expansion of the sheath 8 as the prosthetic device (e.g., implant 12) passes through the sheath 8 in the direction of arrow 132 (e.g., distal direction). As the prosthetic device / implant 12 advances through the sheath 8, the sheath may expand elastically to a second diameter D2 corresponding to the size or diameter of the prosthetic device / implant 12. As the prosthetic device / implant 12 advances through the sheath 8, the prosthetic device / implant 12 may apply a longitudinal force to the sheath 8 in the direction of motion due to frictional contact between the prosthetic device and the inner surface of the sheath 8. However, as described above, in some implementations, the inner layer 102 and / or outer layer 108 may resist axial stretching so that the length L of the sheath 8 remains constant or substantially constant. This can lengthen the braided second layer 104, thereby reducing or preventing contraction of the lumen 112.

[0153] On the other hand, the angle θ between filaments 110A and 110B may increase as the sheath 8 expands to a second diameter D2 to accommodate the artificial device / implant 12. This may result in shortening of the braided second layer 104. However, in some implementations, since the filaments 110 do not engage with or bond to the inner layer 102 or the outer layer 108, the shortening of the braided second layer 104 due to the increase in angle θ does not affect the overall length L of the sheath 8. Furthermore, due to longitudinally extending folds / ridges 126 formed within the inner layer 102 and the outer layer 108, the inner layer 102 and the outer layer 108 can expand to a second diameter D2 without rupturing, despite being relatively thin and relatively inelastic. In this manner, the sheath 8 can elastically expand from its original diameter D1 to a second diameter D2, which is larger than diameter D1, without being stretched and / or contracted as the artificial device / implant 12 advances through the sheath 8. Therefore, the force required to push the artificial implant 12 through the sheath 8 is significantly reduced.

[0154] Furthermore, due to the radial force applied by the elastic third layer 106, the radial expansion of the sheath 8 may be localized to a specific portion of the sheath 8 occupied by the prosthetic device. For example, referring to Figure 14, as the prosthetic device / implant 12 moves distally through the sheath 8, a portion of the sheath 8 immediately proximal to the prosthetic device (e.g., implant 12) may fold radially back to its initial diameter D1 under the influence of the elastic third layer 106. The inner layer 102 and the outer layer 108 may buckle as the circumference of the sheath 8 is reduced, thereby resulting in the reformation of the ridges 126 and valleys 128. This can reduce the size of the sheath 8 required to accommodate a prosthetic device of a given size. Furthermore, the temporary and local nature of the dilation means that only a portion of the sheath 8 occupied by the prosthetic device expands beyond its original diameter, and once the device has passed, the sheath 8 folds back to its initial diameter, thus reducing trauma to the blood vessel into which the sheath 8 is inserted and to the surrounding tissue. This limits the amount of tissue that needs to be stretched to introduce the prosthetic device, and the amount of time that a given portion of the blood vessel must be dilated.

[0155] In another example, in the layered sheath 208 structure, Figures 15–23 show various features of the coaxial layered structure of the expandable sheath 8 of Figure 1 in a different embodiment. Similar reference numerals are used to describe similar elements. Naturally, the variations (e.g., materials, and alternative configurations) described herein with reference to Figures 11–14 may also be applied to the examples shown in Figures 15–23. Furthermore, the variations described herein with reference to Figures 15–23 may also be applied to the sheaths described in Figures 11–14.

[0156] Similar to the various implementations of sheath 8 described herein with reference to Figures 11-14, the sheath 208 in Figures 15-23 includes multiple layers. For example, the sheath 208 shown in Figures 15-23 also includes an inner layer 202 and an outer layer 204 positioned around the inner layer 202. The inner layer 202 may define a lumen 212 through which a delivery device / implant 12 can move into the patient's blood vessels for delivery, removal, repair, and / or replacement of an artificial device, moving in a direction along the longitudinal axis X. Similar to the sheath 208 shown in Figures 11-14, as the artificial device passes through the sheath 208, the sheath 208 expands locally from a first stationary / non-expanded diameter to a second expanded diameter to accommodate the artificial device. After the artificial device has passed through a particular location in the sheath 208, each continuous expanded portion, or segment, of the sheath 208 returns, at least partially, to a smaller stationary / non-expanded diameter. In this configuration, the sheath 208 can be considered self-expanding in that it does not require the use of balloons, expanders, and / or occluders for expansion.

[0157] As in the examples herein, the inner layer 202 and the outer layer 204 may comprise any suitable material. Suitable materials for the inner layer 202 include polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), nylon, polyethylene, polyether block amide (e.g., PEBAX), and / or combinations thereof. In some implementations, the inner layer 202 may optionally comprise a lubricating, low-friction, or hydrophilic material, such as PTFE. Such low-friction materials may facilitate the passage of artificial devices through the lumen defined by the inner layer 202. In some examples, the inner layer 202 may have a coefficient of friction of less than about 0.1. Some examples of the sheath 208 may optionally comprise a lubricating liner on the inner surface of the inner layer 202. Suitable lubricating liners include materials that can further reduce the coefficient of friction of the inner layer 202, such as PTFE, polyethylene, polyvinylidene fluoride, and combinations thereof. Suitable materials for lubricating liners also include other materials having a coefficient of friction of preferably about 0.1 or less.

[0158] Suitable materials for the outer layer 204 include nylon, polyethylene, Pebax, HDPE, polyurethane (e.g., Tecoflex), and other medical-grade materials. In one implementation, the outer layer 204 may include extruded high-density polyethylene (HDPE) and Tecoflex (or other polyurethane material) as a composite. In some implementations, Tecoflex can act as an adhesive between the inner layer 202 and the outer layer 204 and may be present only along a portion of the inner surface of the outer layer 204. Other suitable materials for the inner layer 202 and the outer layer 204 are also disclosed in U.S. Patent Publications 8,690,936 and 8,790,387, which are incorporated herein by reference.

[0159] Furthermore, some examples of sheath 208 include an optional external hydrophilic coating on the outer surface of the outer layer 204. Such a hydrophilic coating can facilitate the insertion of sheath 208 into the patient's blood vessels. Examples of suitable hydrophilic coatings include Harmony® Advanced Lubricity Coatings and other Advanced Hydrophilic Coatings, available from SurModics, Inc., Eden Prairie, Minnesota. DSM Medical Coatings (available from Koninklijke DSM NV, Heeren, Netherlands), as well as other hydrophilic coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride) are also suitable for use with sheath 8.

[0160] Figure 16 provides a partial cross-section of the distal end of the sheath 208 along the cross-sectional line 16-16 identified in Figure 15. As described herein, the sheath 208 may be inserted into a blood vessel (e.g., a femoral artery or an iliac artery) by passing through the patient's skin, such that the soft tip portion 206 at the distal end 210 of the sheath 208 is the first portion of the sheath 208 to be inserted into the blood vessel. As most commonly seen in Figure 16, the soft tip portion 206 may, in some examples, include low-density polyethylene (LDPE) and may be configured to minimize trauma or damage to the patient's blood vessel as the sheath 208 is navigated through the vascular structure. For example, in some implementations, the soft tip portion 206 may be slightly tapered to facilitate passage through the blood vessel. In some implementations, the flexible tip portion 206 may be fixed to the distal end 210 of the sheath 208, for example, by thermally bonding the flexible tip portion 206 to the inner layer 202 and outer layer 204 of the sheath 208. Such a flexible tip portion 206 may be provided with lower hardness than the rest of the sheath 208. In some examples, the flexible tip portion 206 may have a Shore hardness of about 25D to about 40D. The flexible tip portion 206 is radially expandable and configured for the prosthetic device to pass through the distal opening of the sheath 208. For example, in some implementations, the flexible tip portion 206 may be formed with weakened portions, such as axially extending score lines or perforation lines, which are divided and configured for the flexible tip portion 206 to expand radially as the prosthetic device passes through it.

[0161] Figure 17 shows a cross-sectional view of the sheath 208 taken near the distal end 210 of the sheath 208, as indicated by the cross-sectional line 17-17 in Figure 16. As shown in Figures 16 and 17, the sheath 208 may optionally include at least one radiopaque filler or marker. In some implementations, the radiopaque filler or marker may include a discontinuous or C-shaped band (marker 216) located near the distal end 210 of the sheath 208. Marker 216 may be associated with the inner layer 202 and / or outer layer 204 of the sheath 208. For example, in some implementations, as shown in Figure 17, marker 216 may be located between the inner layer 202 and the outer layer 204. In other examples, marker 216 may be associated with the outer surface of the outer layer 204. In some examples, the marker 216 may be embedded in or mixed within the inner layer 202 and / or the outer layer 204.

[0162] Figures 18 and 19 show further cross-sectional views taken at different points along the sheath 208. Figure 18 shows a cross-section of a segment of the sheath 208 near the proximal end 214 of the sheath 208, as indicated by the cross-sectional line 18-18 in Figure 15. At this location, the sheath 208 includes an inner layer 202, an outer layer 204, an elastic outer layer 250 / outer jacket, and a strain-relieving layer 26. At this location, near the proximal end of the sheath 208, the inner layer 202 and the outer layer 204 are substantially tubular. Here, the inner layer 202 and the outer layer 204 may be formed without any slits or folded portions within the layers. In contrast, as described herein, the inner layer 202 and the outer layer 204 may have different configurations at different locations along the sheath 208, for example, at the points indicated by section lines 19-19 in Figure 15 and / or at the points indicated by section lines 22-22 in Figure 21.

[0163] As shown in Figure 19, the inner layer 202 may be positioned to form a substantially cylindrical lumen 212 through it. The inner layer 202 may include one or more folded portions 218. In the implementation shown in Figure 19, the inner layer 202 is positioned to have one folded portion 218, which may be located on both sides of the inner layer 202. The inner layer 202 may be continuous in that there are no fractures, slits, or perforations in the inner layer 202. The outer layer 204 may be positioned in an overlapping manner such that the overlapping portion 220 overlaps with at least a portion of the folded portion 218 of the inner layer 202. As shown in Figure 19, the overlapping portion 220 also overlaps with the base portion 222 of the outer layer 204. The base portion 222 may be positioned below both the overlapping portion 220 of the outer layer 204 and the folded portion 218 of the inner layer 202. Therefore, the outer layer 204 may be discontinuous in that it includes slits or cuts to form the overlapping portion 220 and the base portion 222. In other words, the first edge 224 of the outer layer 204 is spaced apart from the second edge 225 of the outer layer 204 so as not to form a continuous layer.

[0164] As shown in Figure 19, the sheath 208 may also optionally include a thin layer of bonding or adhesive material 228 positioned between the inner layer 202 and the outer layer 204. In some implementations, the adhesive material 228 may include a polyurethane material such as Tecoflex. The adhesive material 228 may be positioned on the inner surface of at least a portion of the outer layer 204 to provide adhesion between the inner layer 202 and selected portions of the outer layer 204. For example, in some implementations, the outer layer 204 may consist only of a Tecoflex layer (adhesive material 228) around a portion of the inner surface 230 facing the lumen-forming portion of the inner layer 202. In other words, in some implementations, the Tecoflex layer may be positioned so as not to contact the folded portion 218 of the inner layer 202. In other implementations, the Tecoflex layer may be positioned in different configurations as desired for specific applications. For example, as shown in Figure 19, the Tecoflex layer may be positioned along the entire inner surface 230 of the outer layer 204. In an alternative example, the Tecoflex layer may be applied to the outer surface of the inner layer 202 instead of the inner surface of the outer layer 204. The Tecoflex layer may be applied to all or selected portions of the inner layer 202. For example, the Tecoflex layer may be formed only on a portion of the inner layer 202 facing the lumen-forming portion of the outer layer 204, rather than on the folded portion 218. The configuration in Figure 19 allows for radial expansion of the sheath 8 when a radially outward force is applied from the inside (for example, by passing a medical device such as an artificial heart valve into the lumen 212). When a radial force is applied, the folded portion 218 can be separated at least partially, straightened, and / or unfolded, and / or the overlapping portion 220 of the outer layer 204 and the base portion 222 can slide circumferentially relative to each other, thereby allowing the diameter of the lumen 212 to expand.

[0165] In this configuration, the sheath 208 is configured to expand from a stationary / non-expandable configuration (Figure 19) to an expanded configuration shown in Figure 20. In the expanded configuration, an annular gap 232 may be formed between the overlapping portion 220 of the outer layer 204 and the longitudinal edge of the base portion 222, as shown in Figure 20. When the sheath 208 expands at a particular position, the overlapping portion 220 of the outer layer 204 may move circumferentially relative to the base portion 222 as the folded portion 218 of the inner layer 202 is unfolded. This movement may be facilitated by the use of a low-friction material for the inner layer 202, such as PTFE. Furthermore, the folded portion 218 may be at least partially separated and / or unfolded to accommodate a medical device having a diameter larger than the diameter of the lumen 212 in the stationary / non-expandable configuration. As shown in Figure 20, in some implementations, the folded portion of the inner layer 202 can be fully unfolded, resulting in the inner layer 202 forming a cylindrical tube in the expanded configuration.

[0166] Similar to the exemplary sheath 8 in Figure 14, the sheath 208 may be configured to locally expand at specific locations along the length of the lumen 212, corresponding to the position of the medical device, and then locally contract as the medical device passes through those specific locations. Thus, as the medical device is introduced through the sheath 208, it advances longitudinally along the length of the sheath 208, and as the device moves along the length of the sheath 208, bulges representing continuous local expansion and contraction may become visible. Each segment of the sheath 208 locally contracts after the removal of any radially outward force such that the sheath 208 returns at least partially to the original stationary / non-expanded diameter of the lumen 212. Similar to the exemplary sheath 8 described herein, an elastic outer layer 250 may be provided (optionally) along the sheath 208 and may bias the inner layer 202 and outer layer 204 toward a non-expanded configuration.

[0167] The layers 202 and 204 of the sheath 208 may be configured to have a folded portion 218 along at least a portion of the length of the sheath 208, as shown in Figure 19. In some examples, the inner layer 202 and the outer layer 204 may be configured along length A (Figure 15), as shown in Figure 19, such that the folded portion 218 extends from a position adjacent to the soft tip portion 206 to a position closer to the proximal end 214 of the sheath 208 and / or below the distal end of the strain-relieving layer 26. In this case, the sheath 208 is expandable and contractible along only a portion of the length of the sheath 208 corresponding to length A. In some implementations, this portion of the sheath 208 corresponds to a section of the sheath 208 that is inserted into the narrowest section of the patient's vascular structure.

[0168] In some examples, the folded portion 218 extends from a position adjacent to the soft tip portion 206 and beneath the strain-relieving layer 26, as shown in Figure 21. In this example, the folded structure of the inner layer 202 extends from the soft tip portion 206, beneath the strain-relieving layer 26, and along the tapered portion 248 of the strain-relieving layer 26.

[0169] Figures 22 and 23 provide cross-sectional views of the sheath 208 taken along the strain-relieving layer 26 at the cross-sectional line 22-22 of Figure 21. In this example, the folded portion 218 of the inner layer 202 extends beneath the strain-relieving layer 26. Figure 22 shows a cross-section of the sheath 208 in a stationary / non-expanded configuration with an inner diameter D1. Figure 23 shows a cross-section of the sheath 208 in a (partially) expanded configuration with an inner diameter D2, where D2 is greater than D1.

[0170] As shown in Figures 22 and 23, in some examples, the overlapping portion 220 does not overlap the entire folded portion 218 of the inner layer 202, and therefore, a portion of the folded portion 218 may be positioned to be directly adjacent to / aligned with the strain-relieving layer 26 where the strain-relieving layer 26 is present. Where the strain-relieving layer 26 is not present, a portion of the folded portion 218 may be visible from the outside of the sheath 208 (and / or visible through the elastic outer layer 250, which is described in more detail herein) as seen in Figure 21. In some implementations, the sheath 208 may include a longitudinal seam 234 where the overlapping portion 220 terminates in the folded portion 218. When in use, the sheath 208 may be positioned such that the seam 234 is behind a point on the sheath 208 that is 180 degrees from the seam 234 (for example, facing downward in the field of view of Figure 21). As shown in Figure 21, in some implementations, the seam 234 does not need to extend along the entire length of the sheath 208, but terminates at a transition point between a portion of the sheath 208 having a folded inner layer and a portion of the sheath 208 not having a folded inner layer.

[0171] In some examples, the folded portion 218 may include a weakened portion 236. In some implementations, the weakened portion 236 may include longitudinal perforations, score lines, and / or slits along at least a portion of the length of the inner layer 202. The weakened portion 236 / slits allow two adjacent ends 238, 240 of the folded portion 218 / inner layer 202 to move relative to each other as the sheath 208 expands / moves to the expanded configuration shown in Figure 23. For example, in some implementations, the sheath 208 expands locally as a medical device is inserted through it, causing the weakened portion 236 to split / separate.

[0172] In each of the exemplary sheaths described herein (e.g., sheath 8 and sheath 208), sheath 208 may include an elastic outer layer 250 that expands with sheath 208. The elastic outer layer 250 is described with reference to sheath 208 provided in Figures 15–23, but it is intended that the elastic outer layer 250 may also be provided on sheath 8 provided in Figures 11–14, and any other sheaths described herein. The elastic outer layer 250 may provide radially inward forces to the sheath 208 toward a folded / unexpanded configuration. Similar to the strain-relieving layer 26, the elastic outer layer 250 may also provide hemostasis that helps prevent blood loss during implantation of an artificial device and / or placement of sheath 208 within a blood vessel.

[0173] The elastic outer layer 250 can be positioned around at least a portion of the strain-relieving layer 26, outer layer 204, and / or inner layer 202 (and / or outer layer 108, inner layer 102) of the sheath 208. As shown in Figures 21–23, the outer layer 250 can surround the entire circumference of the outer layer 204 and may extend longitudinally along any portion of the length of the sheath 208, including along the strain-relieving layer 26 (above and / or below). The elastic outer layer 250 extends along the length of at least a portion of the body of the sheath 208. In some examples, the elastic outer layer 250 extends to a point adjacent to the distal end 210 of the sheath 208. In some implementations, the elastic outer layer 250 may extend all the way to the distal end 210 of the sheath 208. In some implementations, the elastic outer layer 250 extends along the entire length of the sheath 208.

[0174] As shown in Figures 17-20, 22, and 23, the elastic outer layer 250 can be a continuous tubular layer without slits or other discontinuities. The elastic outer layer 250 extends between the strain-relieving layer 26 and the outer surface of the outer layer 204. In other examples, the elastic outer layer 250 extends on the outer surface of the strain-relieving layer 26 and on the outer surface of the outer layer 204. In some examples, the elastic outer layer 250 extends both on the strain-relieving layer 26 and / or between the outer layer 204 of the sheath 208 and the strain-relieving layer 26.

[0175] The elastic outer layer 250 may preferably comprise any flexible elastic material(s) that expands and contracts with a high expansion ratio. Preferably, the materials used may comprise high-elasticity, low-durometer polymers such as Pebax, polyurethane, silicone, and / or polyisoprene. The material for the elastic outer layer 250 may be selected so as not to hinder the expansion of the inner layer 202 and outer layer 204 of the sheath 208. The elastic outer layer 250 may have a thickness in the range of, for example, about 0.001 inches to about 0.010 inches. In some implementations, the elastic outer layer 250 may have a thickness in the range of about 0.003 inches to about 0.006 inches. The elastic outer layer 250 may be configured to stretch and expand as the sheath 208 expands, as shown in the expansion configuration of Figure 20.

[0176] As shown in Figures 2, 15, and 21, sheath 8 and sheath 208 include a strain relief layer 26. The strain relief layer 26 is described with reference to sheath 208 provided in Figures 15–23, but the strain relief layer 26 is also intended to be included in sheath 8 provided in Figures 11–14 and any other sheaths described herein.

[0177] The strain relief layer 26 / tube is provided adjacent to the proximal end of the sheath 208 and extends along / on the outer surface of the sheath 208. In some examples, the strain relief layer 26 is provided on the outer layer 204 (and / or outer layer 208) of the sheath 208. The strain relief layer 26 forms a smooth transition between the sheath hub 20 and the sheath 208, facilitating the mating of the sheath 208 with the sheath hub 20.

[0178] Furthermore, as described in more detail herein, the strain-relieving layer 26 provides a region of higher durometer, or stiffness, that limits the expansion of the underlying sheath layer. This helps ensure hemostasis between the portion of sheath 8,208 inside the patient and the sheath hub (outside the patient). The increased durometer and / or stiffness along the strain-relieving layer 26 helps prevent blood from flowing between the various layers of sheath 208 outside the patient during the procedure and helps withstand the blood pressure that would otherwise cause the sheath 208 to "balloon up" with body fluid / blood. In addition, in some implementations, the strain-relieving layer 26 can be sized and configured to form a seal with the patient's artery upon insertion, thereby substantially preventing blood from flowing between the strain-relieving layer 26 and the vessel wall. For example, the strain relief layer 26 does not extend completely to the distal end 210 of the sheath 208, but the strain relief layer 26 may extend sufficiently distally along the sheath 208 so that when the sheath 208 is inserted into the patient's blood vessel, a portion of the strain relief layer 26 extends through the arterial incision site and seals against the arterial incision site.

[0179] As described herein, the strain relief layer 26 is provided on the outer layer 204 (and / or outer layer 108) of the sheath 208. In some implementations, the strain relief layer 26 can be bonded to the outer layer 204 to prevent it from sliding and "overlapping" on the outer layer 204 in response to frictional forces applied by the surrounding tissue during insertion of the sheath 208 into the patient's vascular structure. For example, the strain relief layer 26 may be bonded at the proximal and / or distal ends of the outer layer 204. In some implementations, at the proximal and distal ends, the strain relief layer 26 may be bonded to the outer layer 204 around its entire circumference. In some implementations, at the distal end of the sheath 208, the strain relief layer 26 may alternatively be bonded to the inner layer(s) of the sheath 208. For example, the strain relief layer 26 may be bonded to the distal end face of the inner layer 202.

[0180] Figures 18, 22, and 23 show cross-sectional views of the sheath 208 along the strain-relieving layer 26. Figure 18 shows a cross-section of a segment of the sheath 208 near the proximal end 214 of the sheath 208, as indicated by lines 18-18 in Figure 15. Similarly, Figures 22 and 23 show various exemplary sheath cross-sectional segments near the proximal end 214 of the sheath 208 and near the distal end of the strain-relieving layer 26, as indicated by cross-sectional lines 22-22 in Figure 21. As shown in each of Figures 15-23, the sheath 208 at this location may include an inner layer (liner) 202, an outer layer 204, an adhesive material layer 228, an optional elastic outer layer 250, and a strain-relieving layer 26.

[0181] The strain relief layer 26 extends circumferentially around at least a portion of the inner layer 202 and the outer layer 204. The strain relief layer 26 extends from the proximal end 214 of the sheath 208 toward the distal end 210 of the sheath 208. As shown in Figure 21 (and Figure 15), the strain relief layer 26 extends along a length L along at least a portion of the body of the sheath 208. In some examples, the strain relief layer 26 extends to a point adjacent to the distal end 210. In further examples, the strain relief layer 26 extends completely to the distal end 210 of the sheath 208. In some examples, the longitudinal length L of the strain relief layer 26 can range from about 10 cm to the entire length of the sheath 208.

[0182] In some implementations, the strain relief layer 26 extends to / adjacent to the proximal end 214 of the sheath 208, providing a compression fit on the distal end of the sheath hub 20, thereby coupling the sheath 208 to the sheath hub 20. Additionally or alternatively, the strain relief layer 26 may be fixed between the sheath hub 20 and the sheath hub cap 22 (or other fastening device for coupling the proximal end of the sheath 208 to the sheath hub 20), as shown in Figures 5A and 5B. In some examples, the strain relief layer 26 does not extend completely to the proximal end 214 of the sheath 208.

[0183] Naturally, as shown herein, the strain-relieving layer 26 may have similar composition and properties to the inner layer 202 and the outer layer 204, as disclosed herein. Various compositions are disclosed, for example, in application PCT / US2021 / 301275, entitled "Expandable sheath for introducing an endovascular delivery device into a body," which is incorporated herein by reference.

[0184] In some implementations, the strain relief layer 26 may include a lubricating, low-friction, and / or relatively inelastic material. Preferably, the material used may include a low-elasticity, high-durometer polymer. In some examples, the strain relief layer 26 is composed of the same and / or similar material as the inner layer 202 and / or outer layer 204 (including the inner layer 102 and / or outer layer 108). For example, as described herein with respect to the inner layer 102 and outer layer 108, exemplary materials may include polyurethane (e.g., high-density polyethylene), ultra-high molecular weight polyethylene (UHMWPE) (e.g., Dyneema®), high molecular weight polyethylene (HMWPE), or polyetheretherketone (PEEK). Other suitable materials for the strain-relieving layer 26 may include polyimide, polytetrafluoroethylene (PTFE), ePTFE, ethylenetetrafluoroethylene (ETFE), nylon, polyethylene, polyamide, polyether block amide (e.g., Pebax), and / or any combination of the above. The material for the strain-relieving layer 26 may be selected so that its material properties help to prevent expansion of the underlying layer of the sheath 208.

[0185] The strain relief layer 26 may have a thickness ranging from, for example, about 0.001 inches to about 0.010 inches. In some implementations, the strain relief layer 26 may have a thickness ranging from about 0.003 inches to about 0.006 inches. The wall thickness is measured radially between the inner surface of the strain relief layer 26 and the outer surface of the strain relief layer 26.

[0186] In alternative examples, the material composition and / or wall thickness may vary along the length of the strain-relieving layer 26. For example, the strain-relieving layer 26 may comprise one or more segments, the composition and / or thickness of which may vary by segment. In exemplary embodiments, the durometer grade of the composition may vary along the length of the strain-relieving layer 26 such that segments near the proximal end contain a stiffer material or combination of materials, while segments near the distal end contain a softer material or combination of materials. Similarly, the wall thickness of the strain-relieving layer 26 in segments near the proximal end may be thicker / greater than the wall thickness of the elastic outer layer 250 near the distal end.

[0187] As shown in Figures 15, 21, and 24, the strain relief layer 26 has a proximal end, a distal end, and a central lumen extending longitudinally through it. The strain relief layer 26 includes a substantially tubular proximal portion 242 adjacent to the proximal end of the strain relief layer 26 and a substantially tubular distal portion 246 adjacent to the distal end of the strain relief layer 26. In some implementations, the strain relief layer 26 includes a frustoconical tapered portion 248 extending between the proximal portion 242 and the distal portion 246, such that the diameter of the strain relief layer 26 in the proximal portion 242 is greater than the diameter of the strain relief layer 26 in the distal portion 246 of the strain relief layer 26. The tapered portion 248 and the flared proximal portion 242 help facilitate the transition of the medical device / delivery system as it passes between the larger diameter sheath hub 20 and the smaller diameter sheath 208. In some implementations as described herein, the tapered portion 248 and / or the flared portion 242 provide a radially inward compressive force to the medical device / delivery system as it advances through the sheath hub 20 into the sheath 208, thereby helping to compress the medical device / delivery system into the smaller diameter. As a result, the pushing force required to advance the medical device / delivery system into the sheath 208 is reduced, and the potential for damage to the sheath 208 and / or the medical device / delivery system is reduced.

[0188] As described herein, the strain relief layer 26 is fabricated from a material that is more rigid than the other layers of the sheath 208, such that the strain relief layer 26 inhibits the expansion of a portion of the sheath positioned along / below the strain relief layer 26. Since radial expansion is restricted along the strain relief layer 26, a higher pushing force is required to advance the medical device (implant 12) through the central lumen of the portion of the sheath 208 corresponding to the strain relief layer 26. In some examples, the maximum pushing force through the sheath 208 is experienced near the ends of the strain relief layer 26 (e.g., the proximal and distal ends).

[0189] In some implementations, the thickness and / or composition of the strain relief layer 26 may be adjusted to improve the performance of the strain relief layer 26 and reduce the pressing force. The steps and benefits of pre-expanding the sheath are described with reference to sheath 208, but the corresponding steps and benefits are intended to be provided with respect to sheath 8 and any other sheaths described herein. Pre-expanding sheath 208, or a portion thereof, as described herein, may help reduce the pressing force required to insert a medical device / delivery system through the central lumen of sheath 208.

[0190] Pre-expanding the sheath 208 releases and / or loosens any bonds or adhesions of the layers of the sheath 208 that occur during the manufacturing process, such as bonds between the inner layers 102, 202 and the outer layers 108, 204, bonds between adjacent ridges 126, bonds between the folded portion 218 and the outer layer 204, bonds between the inner layers 102, 202 and the outer layers 108, 204 and the strain relief layer 26, bonds along the strain relief layer 26, or bonds or resistance to expansion at the distal tip. In some implementations, pre-expanding the strain relief layer 26 may also break or separate the weakened portion 236 of the folded portion 218 of the inner layer 202, separating adjacent ends 238, 240 of the folded portion 218 as described herein and shown in Figure 23. With the layers of 208 able to move freely relative to each other, the medical device / delivery system is pressed through the lumen of the sheath 208 with much lower force.

[0191] In some cases, the sheath 208 is pre-dilated by passing a relatively large dilator (e.g., a 22 French dilator) through the sheath 208. Pre-dilation may involve passing the dilator through the strain-relieving layer 26 and / or the distal end of the sheath 208. The pre-dilation step may be performed during manufacturing and / or during the preparation of the sheath 208, before the sheath 208 is inserted into the patient and / or when the sheath 208 is at least partially inserted into the patient. However, in some cases, pre-dilating the sheath 208 may result in a partially open seam or edge between the currently released layers of the sheath 208, which may introduce the possibility of vascular complications, such as difficulty or vascular damage during insertion, movement, and / or withdrawal of the pre-dilated sheath 208, and may not be aesthetically acceptable to the physician.

[0192] The devices, systems, and methods described herein provide systems and methods for pre-expanding a sheath 208, while also preventing longitudinal seams or open edges (e.g., seam 234 as described herein with reference to Figure 21) of the expanded sheath 208 layers from further opening axially, or propagating axially or radially after pre-expansion, for example, during sterilization of the sheath 208 or over time. The systems described herein enable the expansion of the sheath 208 during manufacturing, eliminating the need for medical staff to expand it during sheath preparation, thereby reducing preparation time and eliminating unnecessary opportunities for erroneous and / or negligent damage to the sheath 208.

[0193] Figure 24 shows an exemplary system 300, including a sheath 208 and an expander 350. The system 300 for pre-expanding the sheath, and the corresponding method, are described with reference to the sheath 208 provided in Figures 15-23, but the system 300 and the corresponding method are intended to be used with the sheath 8 provided with reference to Figures 11-14, or any other expandable sheath described herein.

[0194] At least a portion of the sheath 208 (e.g., inner layers 102, 202 and / or strain-relieving layer 26) is configured to expand locally from a non-expandable configuration having a first diameter (e.g., Figures 18-19) to an expanded configuration having a second, larger diameter (e.g., Figure 20). The expansion of the sheath 208 is directed in response to a radially outward force applied to the lumen 212 by the expansion element 365 of the expander 350 (and / or medical device) received within the sheath 208. The sheath 208 then locally contracts, at least partially returning to the non-expandable configuration, as the expander 350 (and / or medical device) passes through the lumen 212. As described in more detail herein, the restraining member 385 restricts the expansion of the sheath 208 adjacent to the restraining member 385 (e.g., inner layer 202 and / or strain-relieving layer 26). By limiting the expansion / unfolding of the sheath 208, the use of the restraining member 385 prevents the longitudinal seams 234, or open edges, between adjacent layers of the expanded sheath 208 from propagating axially and / or opening further radially after pre-expansion.

[0195] The typical sheath shown in Figure 24 (and Figure 25) corresponds to the expandable sheath configuration described herein, e.g., the layered configuration shown in Figures 11-14 and / or Figures 15-23. The sheath 208 includes a continuous inner layer (e.g., inner layer 202) defining a central lumen extending through it, and a corresponding outer layer (e.g., outer layer 204). In the following description, the sheath 208 is described with reference to the layered structure of the sheath 208 in Figures 15-23. However, it is intended that the layered sheath 8 configuration of Figures 11-14 may be used. For example, in some implementations, the sheath 208 includes a continuous inner layer 202 defining a lumen 212 through it. The inner layer 202 includes a proximal portion 320, a main body portion 330, and a folded portion 218 extending along the length of the inner layer 202. In some implementations, the sheath 208 includes an outer layer (e.g., outer layer 204) provided on the inner layer 202 and below or above the tubular strain-relieving layer 26. The sheath 208 includes a tubular strain-relieving layer 26 provided on the inner layer 202 at the proximal end of the sheath 208 and extending along at least a portion of the length of the sheath 208. As described herein, the strain-relieving layer 26 provides a region of higher durometer, or stiffness, that limits the expansion of the underlying sheath layer. The strain-relieving layer 26 is provided at the proximal end of the sheath 208 and extends along at least a portion of the length of the sheath 208. Similar to the inner layer 202 and the outer layer 204, at least a portion of the strain-relieving layer 26 is configured to locally expand from a non-expanded configuration of a first diameter to a second, larger diameter expanded configuration by a radially outward force applied to the lumen 212 of the inner layer 202 by the expander 350 (or medical device), and then locally contract so as the expander 350 (or medical device) passes through the lumen 212, it returns at least partially to the non-expanded configuration.

[0196] As shown in Figure 24, the sheath 208 includes a restraining member 385 provided on the sheath 208 to limit the expansion / unfolding of adjacent / base portions of the sheath 208. In some implementations, the restraining member 385 limits the expansion / unfolding of the folded portion 218 of the inner layer 202, and / or movement between the inner layer 202 and the outer layer 204, when the sheath moves from a non-expanded configuration to an expanded configuration. As a result, this prevents a longitudinal seam 234 from forming / opening between the overlapping portion 220 of the outer layer 202 and the folded portion 218 of the inner layer 202 (Figure 21). This also helps prevent the formation of an opening / gap between adjacent layers of the folded portion 218 from propagating axially (e.g., proximal or distal along the length of the sheath 8). It may also help prevent any opening / gap formed between adjacent layers of the folded portion 218 from opening further radially after pre-expansion.

[0197] In some implementations, as shown in Figure 24, the restraining member 385 is positioned on the distal end 342 of the strain-relieving layer 26. As a result, the restraining member 385 restricts the expansion of the base portion and / or adjacent portions of at least one of the inner layer 202 and the strain-relieving layer 26. For example, in some implementations, the restraining member 385 is provided along the length of the sheath 208 at a position corresponding to the distal end 342 of the strain-relieving layer 26 and extends along the length of the strain-relieving layer 26 (part A), extending from the distal end 342 toward the proximal end of the strain-relieving layer 26. In some implementations, as provided in Figure 24, the restraining member 385 extends along a second length (part B) of the sheath 208, extending from the distal end 342 of the strain-relieving layer 26 toward the distal end of the sheath 208.

[0198] The restraining member 385 may be constructed from a material having lower elasticity than the sheath 208 and / or the underlying layer of the strain-relieving layer 26, so as to limit and / or prevent the radial expansion of the sheath 208 / strain-relieving layer 26. In some implementations, the restraining member 385 is constructed from tape, shrink tube, elastic tube, package feature, or other structure or material provided on the sheath 208 to limit radial expansion. In some implementations, the restraining member 385 is bonded to the sheath 208. For example, in some implementations, the restraining member 385 is bonded to the outer surface of the inner layer 202 and / or the strain-relieving layer 26. In some implementations, the restraining member 385 is removably bonded to the sheath 208. For example, in some implementations, the inner surface of the restraining member 385 may contain an adhesive (e.g., a temporary / releasable adhesive and / or a resealable adhesive) for bonding the restraining member 385 to the sheath 208. In some implementations, the suppression member 385 includes a shrink tube bonded to at least one of the inner layer 202 or the strain relief layer 26 by a shrink process (e.g., a shrink heating process). In some implementations, the suppression member 385 includes a release feature 386 for removing the suppression member 385 from the sheath 208. For example, the release feature 386 may be used to partially or completely remove the suppression member 385 from the inner layer 202 and / or the strain relief layer 26. In some implementations, the release feature 386 may include at least one of a weakening portion (e.g., a perforation, score line, slit, etc.), or a pull tab, and / or a line integrated with the suppression member 385 that, upon activation, separates the suppression member 385 from or at least partially along the sheath 208.

[0199] In some implementations, as shown in Figure 25, the release feature 386 is incorporated into a package sized and configured to receive the sheath 208. Figure 25 shows the sheath system 300 contained within its corresponding package tray 400. The tray 400 includes a recess / recess sized and configured to reliably receive the components of the sheath system 300. When the release feature 386 is incorporated into the tray 400, removing the sheath 208 from the tray 400 also removes the retaining member 385 from the inner layer 202 and / or the strain relief layer 26. For example, in some implementations, the retaining member 385 and / or a portion of the release feature 386 (e.g., a pull tab or wire) are fixedly coupled to the tray 400 so that when the sheath 208 is removed from the tray 400, the retaining member 385 is at least partially separated from the sheath 208 and / or aligned with the sheath 208. In some implementations, when separated from the sheath 208, at least a portion of the restraining member 385 may remain attached to the tray 400. In some implementations, when separated from the sheath 208, the restraining member 385 may be separated from both the sheath 208 and the tray 400. In some implementations, when the sheath 208 is removed from the tray 400, a release feature 386 is activated, and the restraining member 385 is separated from and / or along the sheath 208. For example, in some implementations, the release feature 386 includes a weakened portion along the restraining member 385. When the sheath 208 is removed from the tray 400, it is separated or torn along the weakened portion, and the restraining member 385 is removed from or separated along the sheath 208.

[0200] The system 300 includes a dilator 350 sized and configured to be received within a central lumen 212 of the inner layer 202. As shown in Figure 24, the dilator 350 includes an extended dilator shaft 360 on which an expansion element 365 is provided. As described herein, the sheath 208 locally expands from a non-expanding configuration to an expanded configuration in response to a radially outward force applied to the central lumen 212 by the expansion element 365 of the dilator 350 (and / or medical device).

[0201] In some implementations, the expander shaft 360 includes a body portion 363 adjacent to the proximal end 364 of the expander shaft 360 and a tapered portion 366 extending from the distal end 362 of the expander shaft 360 toward the body portion 363. In some implementations, the length of the expander shaft 360, which is received within the hub opening 376, is adjustable to vary the length 380 of the expander 350, i.e., the length of the expander 350 extending from the expander hub 370. The proximal end 364 of the expander shaft 360 is coupled to the expander hub 370 at the hub opening 376. In some implementations, the hub opening 376 extends from the distal end 372 of the hub toward the proximal end 374 of the hub, and the expander shaft 360 is fixedly coupled within the hub opening 376. During use, the expander shaft 360 is inserted from the proximal end 306 of the sheath hub through the central lumen 308 of the sheath hub 20 into the central lumen 212 of the sheath 208. In some implementations, the expander hub 370 is coupled to the proximal end 306 of the sheath hub 20.

[0202] In some implementations, the extension element 365 is provided on the body portion 363 of the expander 350. In some implementations, as shown in Figure 24, the extension element 365 is defined by the body portion 363 of the expander shaft 360. In other implementations, the extension element 365 includes a radially extending projection from the outer surface of the expander shaft 360. For example, the extension element 365 may include a regularly or irregularly shaped projection extending from the outer surface of the expander shaft 360 around all or part of the circumference of the expander 350.

[0203] In some implementations, the diameter of the expansion element 365 is larger than the unexpanded diameter of the sheath 208, and as a result, the movement of the expansion element 365 through the lumen 212 of the sheath 208 causes the sheath 208 to radially expand to a diameter larger than its unexpanded diameter. In some implementations, the diameter of the expansion element 365 is 22F. For example, in some implementations, the expansion element 365 has a diameter in the range of 12F to 24F. In another example, the expansion element 365 has a diameter in the range of 14F to 24F. In some examples, the expansion element 365 has a diameter in the range of 14F to 22F. The diameter of the expansion element 365 may be selected based on the diameter of the unexpanded sheath 208 and / or the diameter of the delivery system / medical device, as well as the corresponding desired amount of pre-expansion of the sheath 208.

[0204] Methods for manufacturing and / or manufacturing pre-expanded expandable sheaths for delivering medical devices are described herein. The methods include providing a radially expandable sheath according to any of the examples described herein. Methods for manufacturing a pre-expanded sheath are described with reference to sheath 208 provided in Figures 15-23, but the methods are intended to be used with sheath 8 provided with reference to Figures 11-14, or any other expandable sheaths described herein. In some implementations, sheath 208 includes a continuous inner layer 202 defining the lumen 212 of sheath 8. The inner layer 202 includes a proximal portion 320 and a body portion 330. In some implementations, the inner layer 202 includes a folded portion 218 extending along the length of sheath 208, corresponding to the proximal portion 320 and / or body portion 330. In some implementations, sheath 208 includes a tubular strain-relieving layer 26 provided on the proximal portion 320 of the inner layer 202.

[0205] The method involves positioning the restraining member 385 on a portion of the sheath 208. In some implementations, the restraining member 385 is provided at least on the distal end 342 of the strain-relieving layer 26. The restraining member 385 provides a radially inward force that restricts the expansion of adjacent portions of the inner layer 202 and / or strain-relieving layer 26, thereby preventing the longitudinal seam 234 and / or other open edges formed between adjacent layers of the expanded sheath 208 from propagating axially or opening further radially after pre-expansion. For example, the radially inward force provided by the restraining member 385 restricts the unfolding of the folded portion 218 of the inner layer 202 adjacent to the restraining member 385 as the sheath 208 moves from a non-expanded configuration to an expanded configuration during the advance of the expander 350.

[0206] By providing the restraining member 385 on the distal end 342 of the strain-relieving layer 26, the restraining member 385 is provided on a portion of the sheath 208, including a portion that includes the beginning of the exposed portion of the seam 234. As shown in Figure 21, this includes the proximal portion of the seam 234 extending below the strain-relieving layer 26 and the distal portion of the seam 234 extending along the sheath 208 beyond the strain-relieving layer 26. In some implementations, as shown in Figure 24, the restraining member 385 is provided on the sheath 208 at the distal end 342 of the strain-relieving layer 26, and also extends distally over a first length (part A) of the sheath 208 toward the proximal end of the strain-relieving layer 26, and also extends along a second length (part B) toward the distal end 210 of the sheath 208.

[0207] In some implementations, the restraining member 385 is removably bonded to the sheath 208. For example, the restraining member 385 may be removably bonded to the sheath 8 using a temporary adhesive applied to the inner surface of the restraining member 385 or to corresponding portions of the sheath 208, e.g., the inner layer 202 and / or corresponding portions of the outer surface of the strain-relieving layer 26. In some implementations, the restraining member 385 comprises an adhesive tape applied to the outer surface of the sheath 208. In some examples, the restraining member 385 comprises a shrink tube provided on the sheath 208, to which a shrink process, e.g., a shrink-heating process, is applied.

[0208] The method further includes introducing the expander 350 into the proximal end 214 of the central lumen 212 of the sheath 208, and advancing the expander 350 through a desired length of the sheath 208. In some implementations, the expander 350 advances through the proximal portion 320 of the inner layer 202, which corresponds to the strain relief layer 26. As a result, the expansion element 365 exerts a radially outward force on the central lumen 212 of the sheath 208, causing the inner layer 202 and the strain relief layer 26 adjacent to the expansion element 365 to locally expand from a non-expanded configuration to an expanded configuration. The radially inward force applied by the restraining member 385 restricts the expansion and / or unfolding of the base portion of the sheath 208 as the expander 350 moves through the central lumen 212, i.e., the restraining member 385 restricts the expansion / unfolding of the inner layer 202, the outer layer 204, and / or strain-relieving layer 26 to prevent the propagation of unnecessary openings of the longitudinal seam 234 or other openings.

[0209] In some implementations, the dilator 350 advances through the proximal portion 320 of the inner layer 202 so that the dilation element 365 of the dilator 350 aligns with the distal end 342 of the strain-relieving layer 26, thereby dilating the distal end 342 of the strain-relieving layer 26. For example, the dilator 350 may advance within the lumen 212 of the sheath 208 until the proximal end 368 of the tapered portion 366 of the dilator 350 and / or the distal end of the body portion 363 of the dilator shaft 360 align with the distal end 342 of the strain-relieving layer 26.

[0210] In some implementations, the expander 350 advances through the proximal portion 320 of the inner layer 202 so that the expansion element 365 of the expander 350 is positioned beyond the distal end 342 of the strain relief layer 26. As a result, the distal end 342 of the strain relief layer 26 and a portion of the body portion 330 of the inner layer 202 are at least partially expanded. For example, the expander 350 may advance within the lumen 212 of the sheath 208 until the proximal end 368 of the tapered portion 366 and / or the distal end of the body portion 363 of the expander shaft 360 are positioned beyond the distal end 342 of the strain relief layer 26. In some examples, the expansion element 365 is used to expand / dilate the length of the body portion 330 of the sheath, extending 10–15 mm beyond the distal end 342 of the strain relief layer 26. In this example, extending the length of the main body portion 330 of the sheath 208 beyond the distal end 342 of the strain-relieving layer 26 causes the corresponding length of the folded portion 218 to unfold, at least partially, when the inter-folded bonds of the inner layer 202 are released. Providing the restraining member 385 on this portion of the sheath 208 restricts unfolding and any undesirable separation along the seam 234 or along other openings between adjacent layers of the extended sheath 208.

[0211] In some implementations, the method further includes heating the sheath 208. In some implementations, the size (e.g., width, and / or length) of the seams 234 between adjacent layers of the expanded sheath 208, or open edges, is thermally fixed by heating the sheath 208 in a partially expanded configuration. For example, the heating step may be provided by a thermal sterilization process and / or a thermal fixing process applied to the sheath 208 in an expanded / dilated configuration. However, during the heating step, the sheath 208 is not heated to a temperature or duration sufficient to join the layers of the folded portion 218. In some implementations, the heating step includes heating the sheath 208 at a temperature and duration corresponding to the sterilization process. For example, in some implementations, the sheath 208 is heated to a temperature of 60°C. In some implementations, the sheath 208 is heated for a duration of more than 12 hours. For example, the sheath 208 is heated at 60°C for 24 hours. In some cases, the sheath 208 is heated at 60°C for 26 hours.

[0212] In some implementations, the expander 350 is coupled to the sheath hub 20 and / or the expander hub 370 before the heating step. The expander 350 may advance through the proximal portion 320 of the sheath 208 until the expander hub 370 abuts against the sheath hub 20. In some implementations, the expander hub 370 is then coupled to the sheath hub 20, fixing the position of the expander 350 within the lumen 212 of the sheath 208. In some examples, the expander hub 370 is removably coupled to the sheath hub 20 by mechanical coupling, including, for example, press-fit, interfer-fit, snap-fit, pin, thread, bayonet fastener, clip, and / or lock key. With the expander hub 370 fixed to the sheath hub 20, the user can be assured that no further advance (or retraction) of the expansion element 365 occurs during the heating step, including preparation and cooling.

[0213] In some implementations, the method further includes removing the expander 350 from the lumen 212 of the sheath 208 after the heating step is complete. That is, in some implementations, the expander 350 remains inside the sheath 208 during the heating step. In other implementations, the expander 350 is removed from the lumen 212 of the sheath 208 before the heating step.

[0214] In some implementations, the method further includes removing the suppression member 385 from the sheath 208. For example, after the heating step is complete and before the medical procedure, the suppression member 385 may be removed from the inner layer 202 and / or the strain relief layer 26. In some examples, the suppression member 385 is removed from the sheath 208 before the heating step. In some implementations, the suppression member 385 is removed before the expander 350 is removed from the sheath 208. In some implementations, the suppression member 385 is removed after the expander 350 has been removed from the sheath 208.

[0215] In some implementations, the retaining member 385 includes a release feature 386, as described herein. If the release feature 386 includes a weakening portion (e.g., a perforation, score line, slit, etc.), the retaining member 385 may be removed from the sheath 208 by an outward force acting on the retaining member 385 in a direction that separates it from the sheath 208. The outward force separates the retaining member 385 along the weakening portion. If the release feature 386 includes a pull tab or pull line integrated with the retaining member 385, the retaining member 385 is removed from the sheath 208 when the pull tab / pull line is activated and pulled away from the sheath 208. In some examples, the retaining member 385 is removed from the sheath 208 by cutting or tearing the retaining member 385. For example, if the restraining member 385 is equipped with a heat shrink tube, the restraining member 385 can be removed from the sheath 208 by cutting the heat shrink tube from the sheath 208.

[0216] In some implementations, as described herein, the restraining member 385 is incorporated into the package tray 400 such that removing the sheath 208 from the tray 400 includes at least partially removing the restraining member 385 from the inner layer 202 and / or strain relief layer 26.

[0217] With the restraint member 385 removed, the sheath 208 can be used to deliver the medical device to the surgical site within the patient's blood vessels. A method of delivering the medical device using a pre-expanded sheath is described with reference to the sheath 208 provided in Figures 15-23, but the method is also intended to be used with the sheath 8 provided with reference to Figures 11-14, or any other expandable sheath described herein.

[0218] A method for delivering a medical device using a pre-diluted sheath 208 is described herein. The method includes at least partially inserting the pre-diluted sheath 208 into the patient's blood vessel such that the distal end of the sheath 208 is positioned in close proximity to the treatment site. The sheath 208 may be pre-diluted using a dilator 350 and the method described herein. Because the sheath 208 is pre-diluted, the medical device can be introduced into the central lumen 212 of the (pre-diluted) sheath 208 and into the patient's blood vessel with easier and lower pushing force.

[0219] The method further includes advancing a medical device through a portion of the sheath 208 corresponding to the strain relief layer 26, applying a radially outward force to the central lumen of the sheath 208 (e.g., the inner layer), and locally expanding the sheath 208 (including the inner layer and / or strain relief layer 26) adjacent to the medical device from a non-expanded configuration (Figures 17-19 and 22) to an expanded configuration (Figures 20 and 23). In some examples, the medical device is radially contracted or compressed as it passes through the strain relief layer 20 and enters the smaller diameter distal portion 246 from the proximal portion 242, through the tapered portion 248. As the medical device passes through the corresponding portion of the lumen of the sheath 208, the sheath 208 and the strain relief layer 26 contract locally toward the non-expanded configuration.

[0220] The method further includes advancing the medical device beyond the distal end 342 of the strain-relieving layer 26 into the lumen of the main body portion of the sheath 208 (beyond the strain-relieving layer 26), and finally advancing it beyond the distal opening of the sheath 208 to the treatment site. As the medical device advances beyond the strain-relieving layer 26 through the sheath 208 and through the distal opening, the sheath 208 locally expands from a non-expanded configuration (Figures 11-13A and 17-19) to an expanded configuration (Figures 14, 20) in response to the radially outward force of the medical device exerted on the inner layers / central lumen of the sheath 208, at a position close to the medical device. Since the sheath 208 is pre-expanded as described herein, unfolding and any undesirable separation along the seam 234 or along other openings between adjacent layers of the expanded sheath 208 are limited.

[0221] In some implementations, at least one of the inner and / or outer layers includes at least one folded portion. For example, in some implementations, the sheath includes the ridges 126 and valleys 128 of the fourth (outer) layer 108 of sheath 8 shown in Figures 11-14, and the folded portion 218 of the inner layer 202 of sheath 208 shown in Figures 15-23. By locally expanding the lumen of the sheath, the length of the folded portion is at least partially unfolded. Similarly, by locally contracting the sheath so as to return at least partially to an unexpanded configuration, the length of the folded portion is biased to return towards the folded configuration.

[0222] In some implementations, the outer layer 204 is a discontinuous outer layer, comprising an overlapping portion (e.g., overlapping portion 220) and a base portion (e.g., base portion 222). When the sheath 208 is in a non-expanded configuration, the overlapping portion 220 overlaps with the base portion 222, and the folded portion 218 of the inner layer is positioned between the overlapping portion 220 and the base portion 222 (Figures 17, 19, 22, 23). As the sheath 208 expands locally to / to an expanded configuration, the length of the overlapping portion 220 moves circumferentially relative to the base portion 222 and unfolds. As shown in Figure 20, when the sheath 208 is fully expanded, the inner layer 202 extends into a gap 232 formed between the longitudinal edge of the overlapping portion 220 and the base portion 222 of the outer layer 204.

[0223] As the medical device passes through the lumen of the sheath 208, the sheath 208 locally contracts, at least partially, back to its non-expanded configuration (Figures 11–13A and 17–19).

[0224] The method further includes advancing the medical device through the distal tip 9 / distal opening of the sheath 208 and delivering the medical device to the treatment site. The position of the medical device may be moved or adjusted until the medical device is properly positioned within the patient. Once the medical device is delivered to the treatment site, any delivery systems / components attached to the medical device are then detached from the medical device and withdrawn from the lumen of the sheath 208. The sheath 208 is then removed from the patient and the opening of the blood vessel, and the skin is closed.

[0225] The medical devices described herein may include an artificial device mounted in a radially crimped state on a delivery device, and the act of advancing the artificial device through the lumen of the sheath 208 includes advancing the delivery device and the artificial device through the lumen of the sheath 208 into the patient's vascular structure. In some examples, the artificial device comprises an artificial heart valve, and the method further includes implanting the artificial heart valve at the treatment site of the patient. As described herein, the artificial heart valve is mounted on the balloon catheter of the delivery device as the artificial heart valve advances through the sheath 208.

[0226] Given the many possible ways in which the principle of disclosed disclosure may apply, it should be recognized that the manifestations are merely preferred examples of the disclosure and should not be interpreted as limiting the scope of the disclosure. Rather, the scope of this disclosure is defined by the following claims. Accordingly, the inventors assert that everything within the scope of these claims and the spirit thereof constitutes their disclosure.

[0227] Exemplary embodiments In consideration of the many possible ways in which the principles of disclosure to be disclosed may apply, it should be recognized that the illustrated embodiments are merely preferred examples of the disclosure and should not be interpreted as limiting the scope of the disclosure. Rather, the scope of the disclosure is defined by the following claims. Accordingly, the inventors assert that everything within the scope of these claims and the spirit thereof constitutes their disclosure.

[0228] Example 1. A method for manufacturing a pre-expanded expandable sheath for delivering a medical device, providing a radially expandable sheath comprising: a continuous inner layer defining a lumen through which the inner layer comprises a proximal portion and a main portion, and a folded portion extending along the length of the inner layer; and a tubular strain-relieving layer provided on the proximal portion of the inner layer, wherein at least a portion of the sheath is configured to locally expand from a non-expandable configuration having a first diameter lumen to an expanded configuration having a second, larger diameter lumen, and then locally contract to at least partially return towards the non-expandable configuration; and the strain-relieving layer A method comprising: providing a restraining member positioned on the distal end, wherein the restraining member includes at least one of an inner layer and a strain-relieving layer, and restraining the expansion of an adjacent portion; introducing an expander to the proximal end of the lumen of a sheath, wherein the expander includes an expansion element provided thereon; advancing the expander through the proximal portion of the inner layer such that the expansion element provided on the expander applies a radially outward force to the lumen, causing the inner layer adjacent to the expansion element to locally expand from a non-expanded configuration to an expanded configuration, wherein the restraining member restrains the expansion of the sheath adjacent to the restraining member; and heating the sheath.

[0229] Example 2. Any example of this specification, particularly the method of Example 1, wherein the restraining member restricts the unfolding of the folded portion of the inner layer adjacent to the restraining member as the sheath moves from a non-expanded configuration to an expanded configuration while the expander advances through the proximal portion of the inner layer.

[0230] Example 3. Any example of this specification, particularly the method of Examples 1-2, wherein the restraining member is provided over the length of the sheath at a position corresponding to the distal end of the strain-relieving layer, and extends along a certain length of the strain-relieving layer from the distal end to the proximal end, and along a second length of the sheath from the distal end of the strain-relieving layer towards the distal end of the sheath.

[0231] Example 4. Any example of this specification, particularly the method of Examples 1 to 3, wherein providing the restraining member on the sheath includes bonding the restraining member to at least one of the inner layer or strain-relieving layer.

[0232] Example 5. Any example of this specification, particularly the method of Example 4, wherein the inner surface of the restraining member contains an adhesive for bonding the restraining member to the sheath.

[0233] Example 6. Any example of this specification, particularly the method of Example 4, wherein the restraining member includes a shrink tube, and bonding the restraining member to at least one of an inner layer or a strain-relieving layer provides a shrinking process to the restraining member.

[0234] Example 7. Any example of this specification, particularly the method of Examples 1 to 6, further comprising removing the restraining member from the inner layer and the strain-relieving layer.

[0235] Example 8. Any example of this specification, particularly the method of Example 7, wherein the restraining member is removed after the heating step.

[0236] Example 9. Any example of this specification, particularly the method of Example 7, wherein the restraining member is removed before the heating step.

[0237] Example 10. The release feature provides a radially expandable sheath incorporated into a package, sized and configured to receive the sheath, which includes removing the sheath from the package, and removing the sheath from the package removes the restraining member from the inner layer and strain-relieving layer, any example herein, particularly the method of Example 9.

[0238] Example 11. Any example of this specification, particularly the method of Examples 1-10, wherein advancing the expander through the proximal portion of the inner layer includes advancing the expander's expansion element toward the distal end of the strain-relieving layer so that the distal end of the strain-relieving layer is expanded.

[0239] Example 12. Any example of this specification, particularly the method of Examples 1 to 11, wherein advancing the expander through the proximal portion of the inner layer expands the distal end of the strain-relieving layer and a portion of the main body of the inner layer.

[0240] Example 13. Any example herein, particularly the method of Example 12, wherein extending a portion of the main body beyond the strain-relieving layer extends at least partially the corresponding length of the folded portion.

[0241] Example 14. Any example of this specification, in particular the method of Examples 1 to 13, further comprising removing the expander from the lumen of the sheath after the heating step is complete.

[0242] Example 15. Any example of this specification, in particular the method of Examples 1 to 14, further comprising removing the expander from the lumen of the sheath before the heating step.

[0243] Example 16. Any example of this specification, particularly the method of Examples 1 to 15, wherein at least a portion of the strain-relieving layer is configured to locally expand from a non-expanded configuration by a first diameter to an expanded configuration by a second, larger diameter, and then locally contract back to a non-expanded configuration, at least partially.

[0244] Example 17. Any example of this specification, particularly the method of Example 16, wherein at least a portion of the strain-relieving layer is configured to locally expand from a non-expanded configuration to an expanded configuration in response to a radially outward force applied to the lumen by a dilator, and then locally contract back to a non-expanded configuration as the dilator moves within the lumen, and at least a portion of the sheath is configured to locally expand from a non-expanded configuration to an expanded configuration in response to a radially outward force applied to the lumen of the inner layer by a dilator, and then locally contract back to a non-expanded configuration as the dilator moves within the lumen.

[0245] Example 18. Any example of this specification, particularly the method of Examples 1 to 17, wherein the sheath further comprises an outer layer provided on an inner layer, the outer layer being discontinuous and including an overlapping portion and a base portion, the overlapping portion overlapping with the base portion, at least a portion of the folded portion of the inner layer being positioned between the overlapping portion and the base portion, and a strain-relieving layer extending at least partially on the outer layer.

[0246] Example 19. Any example of this specification, particularly the method of Example 18, wherein in a non-expandable configuration, the folded portion extends circumferentially across the outer surfaces of the inner and / or outer layers, and in an expanded configuration, the local expansion causes the length of the folded portion to be at least partially unfolded, and in an expanded configuration, the local expansion of the sheath causes the length of the overlapping portion to be moved circumferentially relative to the base portion.

[0247] Example 20. In an expanded configuration, local expansion of the sheath forms a gap between the longitudinally extending edges of the outer layer, and at least a portion of the unfolded portion extends into the gap, and a restraining member limits the expansion of the sheath and the width of the gap adjacent to the restraining member, any example herein, particularly the method according to Example 19.

[0248] Example 21. Any example of the method herein, particularly the method of Examples 1-20, further comprising a sheath, the sheath further comprising an elastic outer cover extending at least partially over the sheath, wherein the outer cover expands and contracts locally as the medical device advances through the lumen, and the elastic outer cover applies a radially inward force to the sheath.

[0249] Example 22. Any example of this specification, particularly the method of Examples 1 to 20, wherein the sheath further comprises a sheath hub fixedly coupled to the proximal end of the sheath, the sheath hub comprising a central lumen extending through therein and coaxial with the lumen of the sheath, the dilator shaft being sized and configured to be received within the central lumen of the sheath hub, and the dilator comprising a dilator hub coupled to the proximal end of the dilator shaft, the method comprising advancing the dilator through the proximal portion until the dilator hub abuts against the sheath hub, and coupling the dilator hub to the sheath hub before heating the sheath.

[0250] Example 23. Any example herein, particularly the method according to Examples 1-21, wherein heating the sheath includes heating the sheath to a temperature and duration corresponding to the sterilization process, but during heating, the sheath is not heated to a temperature or duration sufficient to bond the layers of the folded portion together.

[0251] Example 24. Any example herein, in particular the method according to Examples 1 to 23, wherein heating the sheath includes heating the sheath to a temperature of 60°C.

[0252] Example 25. Any example herein, in particular the method of Examples 1 to 24, wherein heating the sheath includes heating the sheath for a duration of more than 12 hours.

[0253] Example 26. A sheath system comprising: a radially expandable sheath, a continuous inner layer defining a lumen through which the inner layer includes a proximal portion, a main portion, and a folded portion extending along the length of the inner layer; a tubular strain-relieving layer provided on the proximal portion of the inner layer; a restraining member positioned on the distal end of the strain-relieving layer, restraining the expansion of at least one adjacent portion of the inner layer and the strain-relieving layer; and an expander sized and configured to be received within the lumen of the inner layer, wherein the expander includes an extended expander shaft and an expansion element provided thereon, and at least a portion of the sheath is configured to locally expand in response to a radially outward force applied to the lumen by the expansion element of the expander, from a non-expandable configuration having a first diameter to an expanded configuration having a second larger diameter, and then, as the expander passes through the lumen, to at least partially locally contract toward the non-expandable configuration, and the restraining member restrains the expansion of the sheath adjacent to the restraining member.

[0254] Example 27. Any example of the sheath system described herein, particularly the one described in Example 26, wherein a restraining member restricts the unfolding of a folded portion of the inner layer adjacent to the restraining member when the sheath moves from a non-extended configuration to an extended configuration.

[0255] Example 28. Any example of a sheath system according to this specification, particularly Examples 26-27, wherein a restraining member is provided over the length of the sheath at a position corresponding to the distal end of the strain-relieving layer, and extends along a certain length of the strain-relieving layer from the distal end to the proximal end, and along a second length of the sheath from the distal end of the strain-relieving layer towards the distal end of the sheath.

[0256] Example 29. Any example of a sheath system according to this specification, particularly those described in Examples 26-28, wherein the restraining member includes at least one of a tape, shrink tube, elastic tube, or package feature.

[0257] Example 30. Any example herein, in particular, of a sheath system as described in Examples 26-29, wherein the restraining member is coupled to the sheath.

[0258] Example 31. Any example of this specification, in particular the sheath system described in Example 30, wherein the inner surface of the restraining member contains an adhesive for bonding the restraining member to the sheath.

[0259] Example 32. Any example of the sheath system described herein, particularly the one described in Example 30, wherein the restraining member includes a shrink tube, and the restraining member is bonded to at least one of an inner layer or a strain-relieving layer by a shrinking process.

[0260] Example 33. Any example of a sheath system according to this specification, particularly those described in Examples 26-32, wherein the restraining member includes a release feature for removing the restraining member from the sheath.

[0261] Example 34. Any example of the sheath system described herein, in particular Example 33, wherein the release feature includes at least one of a weakening portion integrated with the restraining member, or a pull tab, and / or a wire.

[0262] Example 35. Any example of a sheath system described herein, particularly Examples 33-34, in which the release feature is incorporated into a package, sized and configured to receive a sheath, and the sheath can be removed from the package, thereby removing the restraining member from the inner layer and strain-relieving layer.

[0263] Example 36. Any example of a sheath system according to this specification, particularly Examples 26-35, wherein the expander shaft includes a body portion adjacent to the proximal end of the expander shaft and a tapered portion extending from the distal end of the expander shaft toward the body portion, and the expander element is provided on the body portion.

[0264] Example 37. Any example herein, in particular, of the sheath systems described in Examples 26-36, wherein the expansion element is defined by the main body portion of the expander shaft.

[0265] Example 38. A sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 37, wherein the expansion element includes a protrusion extending from the outer surface of the expansion shaft.

[0266] Example 39. A sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 38, wherein the diameter of the expansion element is 22F.

[0267] Example 40. A sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 39, wherein at least a portion of the strain relief layer is configured to locally expand from a non-expanded configuration at a first diameter to an expanded configuration at a second, larger diameter and then at least partially return to the non-expanded configuration and locally contract.

[0268] Example 41. A sheath system according to any example herein, particularly the sheath systems described in Example 40, wherein at least a portion of the strain relief layer is configured to locally expand from a non-expanded configuration to an expanded configuration in response to a radially outward force applied to the lumen by an expander and then at least partially return to the non-expanded configuration and locally contract as the expander 350 moves within the lumen.

[0269] Example 42. A sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 41, wherein the strain relief layer includes a proximal portion adjacent to the proximal end of the strain relief layer, a distal portion adjacent to the distal end of the strain relief layer, and a tapered portion extending between the distal portion and the proximal portion, and the diameter of the proximal portion is larger than the diameter of the distal portion.

[0270] Example 43. A sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 42, wherein the strain relief layer includes a material that is stiffer and / or less elastic than the inner layer and limits the expansion of the inner layer.

[0271] Example 44. A sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 43, wherein the strain relief layer includes a material having a higher durometer than the inner layer such that the strain relief layer limits the expansion of the sheath.

[0272] Example 45. Any example herein, in particular, of the sheath systems described in Examples 26-44, wherein the strain-relieving layer comprises polyurethane.

[0273] Example 46. Any example herein, particularly those described in Examples 26-45, of a sheath system in which the length of the strain-relieving layer remains constant when the strain-relieving layer moves from a non-extended configuration to an extended configuration.

[0274] Example 47. Any example of a sheath system according to this Spec, particularly Examples 26-46, wherein the sheath further comprises an outer layer provided on an inner layer, and the strain-relieving layer comprises a material that is harder and / or less elastic than the inner layer and the outer layer, and restricts the expansion of at least one of the inner layer or the outer layer, and the strain-relieving layer comprises a material that has a higher durometer than the inner layer and / or the outer layer, such that the strain-relieving layer restricts the expansion of at least one of the inner layer or the outer layer.

[0275] Example 48. Any example of a sheath system according to this specification, particularly examples 26-46, further comprising an outer layer provided on an inner layer, wherein the outer layer is discontinuous and includes an overlapping portion and a base portion, the overlapping portion overlapping with the base portion, at least a portion of the folded portion of the inner layer is positioned between the overlapping portion and the base portion, and a strain-relieving layer extends at least partially on the outer layer.

[0276] Example 49. Any example herein, in particular Example 48, of a sheath system in a non-extendable configuration in which the folded portion extends circumferentially across the outer surfaces of the inner and / or outer layers.

[0277] Example 50. Any example of a sheath system according to this specification, particularly examples 48-49, in which an extended configuration in which local extension at least partially unfolds the length of a folded portion to form an unfolded portion of the inner layer, and in an extended configuration in which local extension of the sheath moves the length of an overlapping portion circumferentially relative to the base portion.

[0278] Example 51. Any example of the sheath system described herein, particularly Example 50, in an expanded configuration, in which local expansion of the sheath forms a gap between longitudinally extending edges of the outer layer, and at least a portion of the unfolded portion extends into the gap, and a restraining member limits the expansion of the sheath and the width of the gap adjacent to the restraining member.

[0279] Example 52. Any example herein, in particular, of the sheath systems described in Examples 26-51, in which the total length of the strain relief layer and / or the sheath does not change when the sheath and / or strain relief layer moves between a non-expanded configuration and an expanded configuration.

[0280] Example 53. Any example of a sheath system according to this specification, particularly examples 26-52, wherein the lumen of the inner layer is cylindrical in both non-expandable and expanded configurations.

[0281] Example 54. Any example of a sheath system according to this specification, particularly examples 26-53, wherein the inner layer comprises PTFE and the outer layer comprises HDPE and / or Tecoflex.

[0282] Example 55. Any example herein, in particular Examples 47-57, of a sheath system in which the inner layer and the outer layer are bonded together.

[0283] Example 56. Any example herein, in particular, of a sheath system as described in Examples 47-55, in which the inner layer and the outer layer are thermally bonded together.

[0284] Example 57. Any example herein, in particular, of a sheath system as described in Examples 47-56, wherein the inner layer and the outer layer are bonded together by an adhesive.

[0285] Example 58. Any example herein, in particular, of the sheath systems described in Examples 47-57, wherein the strain-relieving layer is bonded to the outer layer and / or inner layer.

[0286] Example 59. The sheath system according to any example herein, particularly the sheath systems described in Examples 47 - 58, wherein the distortion-relieving layer is thermally and / or adhesively bonded to the outer layer and / or the inner layer.

[0287] Example 60. The sheath system according to any example herein, particularly the sheath systems described in Examples 47 - 59, wherein the inner layer comprises a woven fabric and / or braided filaments.

[0288] Example 61. The sheath system according to any example herein, particularly the sheath systems described in Examples 47 - 60, wherein the inner layer comprises yarn filaments of PTFE, PET, PEEK, and / or nylon.

[0289] Example 62. The sheath system according to any example herein, particularly the sheath systems described in Examples 47 - 61, wherein the outer layer comprises polyurethane.

[0290] Example 63. The sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 62, further comprising an elastic outer cover that at least partially extends over the sheath, wherein when the dilator advances through the lumen, the outer cover locally expands and contracts, the elastic outer cover applies a radially inward force on the sheath, and the elastic outer cover comprises PEBAX, polyurethane, silicone, or polyisoprene, or a combination thereof.

[0291] Example 64. The sheath system according to any example herein, particularly the sheath systems described in Examples 26 - 63, further comprising a sheath hub fixedly coupled to the proximal end of the sheath, the sheath hub comprising a central lumen that extends therethrough and is coaxial with the lumen of the sheath, the dilator shaft being sized and configured to be received within the central lumen of the sheath hub, the dilator comprising a dilator hub coupled to the proximal end of the dilator shaft, the dilator hub being configured to be coupled to the sheath hub.

[0292] Example 65. The sheath system according to any example herein, particularly the sheath systems described in Example 64, wherein the sheath hub comprises one or more seals for forming a seal around the outer surface of a delivery device movable through the central lumen of the sheath hub.

[0293] Example 66. A sheath system kit comprising: a radially expandable sheath, a continuous inner layer defining a lumen through which the inner layer includes a proximal portion, a main portion, and a folded portion extending along the length of the inner layer; a tubular strain-relieving layer provided on the proximal portion of the inner layer; a restraining member positioned on the distal end of the strain-relieving layer, which restricts the expansion of at least one adjacent portion of the inner layer and the strain-relieving layer; an expander sized and configured to be received within the lumen of the inner layer, which includes an extended shaft and an expansion element provided thereon; and a sheath, and a sheath sized to receive the expander. A sheath system kit comprising a tray and a sheath comprising a tray comprising a release mechanism coupled to a restraining member, wherein when the sheath is removed from the tray, the release mechanism holds the restraining member and thereby removes it from the sheath, and at least a portion of the sheath is configured to locally expand in response to a radially outward force applied to the lumen by the expansion element of an expander, from a non-expanded configuration in which the lumen has a first diameter to an expanded configuration in which the lumen has a second diameter which is larger, and the expander then locally contracts, at least partially back toward the non-expanded configuration as it passes through the lumen, and the restraining member restricts the expansion of the sheath adjacent to the restraining member.

[0294] Example 67. A method for delivering a medical device through a sheath, the method comprising: providing a radially expandable sheath, comprising: an inner layer comprising a continuous inner layer defining a lumen through which thereafter the inner layer comprising a proximal portion and a main portion and a folded portion extending along the length of the inner layer; a tubular strain-relieving layer provided on the proximal portion of the inner layer; and a restraining member positioned on the distal end of the strain-relieving layer, the restraining member restricting the expansion of at least one adjacent portion of the inner layer and the strain-relieving layer; removing a dilator received from the lumen of the inner layer, wherein the restraining member restricts the expansion of the sheath due to a radially outward force applied by the dilator; introducing a medical device into the proximal end of the central lumen of the sheath; and the proximal part of the inner layer A method comprising: advancing a medical device through a portion, locally expanding the inner layer and the strain-relieving layer adjacent to the medical device from a non-expanded configuration to an expanded configuration; locally contracting the strain-relieving layer toward the non-expanded configuration as the medical device passes through the corresponding portion of the lumen of the sheath; advancing the medical device beyond the distal end of the strain-relieving layer; advancing the medical device through the main body portion of the lumen of the sheath, locally expanding the main body portion of the sheath from a non-expanded configuration to an expanded configuration adjacent to the medical device in response to an outward radial force of the medical device applied to the inner layer; locally contracting the sheath toward the non-expanded configuration, at least partially, as the medical device passes through the lumen; and advancing the medical device beyond the distal opening of the sheath.

[0295] Example 68. Any example of this specification, particularly the method of Example 67, wherein at least a portion of the sheath is configured such that the lumen expands locally from a non-expandable configuration having a first diameter to an expanded configuration having a second, larger diameter in response to a radially outward force applied to the lumen by the expansion element of the expander, and then the expander locally contracts, at least partially back toward the non-expandable configuration, as it passes through the lumen.

[0296] Example 69. A method for inserting a medical device into a patient's blood vessel, the method comprising: providing a radially expandable sheath, the sheath comprising: an inner layer which is a continuous inner layer defining a lumen through which therethrough, and which includes a proximal portion, a main portion, and a folded portion extending along the length of the inner layer; a tubular strain-relieving layer provided on the proximal portion of the inner layer; and a restraining member positioned on the distal end of the strain-relieving layer which restricts the expansion of at least one adjacent portion of the inner layer and the strain-relieving layer; removing a dilator received from the lumen of the inner layer such that the restraining member restricts the expansion of the sheath due to an outwardly directed radial force applied by the dilator; removing the restraining member from the sheath; at least partially inserting the sheath into the patient's blood vessel; and inserting a medical device into the proximal end of the central lumen of the sheath. A method comprising: advancing a medical device through the proximal portion of the inner layer, thereby applying a radial force directed laterally toward the central lumen by the medical device, locally expanding the inner layer and the strain-relieving layer adjacent to the medical device from a non-expanded configuration to an expanded configuration; locally contracting the strain-relieving layer toward a non-expanded configuration as the medical device passes through the corresponding portion of the lumen of the sheath; advancing the medical device beyond the distal end of the strain-relieving layer; advancing the medical device through the lumen of the main body of the sheath, thereby locally expanding the main body of the sheath from a non-expanded configuration toward an expanded configuration in response to the radially outward force of the medical device applied toward the inner layer; locally contracting the sheath toward a non-expanded configuration, at least partially, as the medical device passes through the lumen; and advancing the medical device beyond the distal opening of the sheath toward a treatment site within the blood vessel.

[0297] Example 70. Any example herein, in particular the method according to Example 69, wherein the expander expands the distal end of the strain-relieving layer.

[0298] Example 71. Any example herein, particularly the method of Examples 69-70, wherein the inner layer includes at least one folded portion, and the length of the folded portion is at least partially unfolded by locally expanding the lumen of the sheath.

[0299] Example 72. Any example of the method according to this specification, particularly the method according to Examples 69-71, wherein the sheath further comprises an outer layer provided on an inner layer, the outer layer being discontinuous and comprising an overlapping portion and a base portion, and when the sheath is in a non-expandable configuration, the overlapping portion overlaps the folded portion and the base portion of the inner layer, the strain-relieving layer extends at least partially on the outer layer, and the medical device is an artificial device mounted in a radially crimped state on a delivery device.

[0300] Example 73. Any example herein, particularly the method of Example 72, which includes advancing an artificial device through the lumen of a sheath, and advancing the artificial device through the lumen of a sheath into the vascular structure of a patient.

[0301] Example 74. Any example of this specification, particularly the method of Example 73, wherein the artificial device comprises an artificial heart valve, and the method further comprises implanting the artificial heart valve at a treatment site in a patient.

[0302] Example 75. Any example herein, particularly the method according to Examples 73-74, wherein the artificial heart valve is attached to the balloon catheter of the delivery device as the artificial heart valve advances through the sheath.

[0303] Example 76. Any example herein, particularly the method according to Examples 69-75, wherein the sheath is inserted into the femoral artery of the patient.

Claims

1. A method for manufacturing a pre-expanded, expandable sheath for delivering medical devices, To provide a radially expandable sheath, wherein the sheath is A continuous inner layer defining the lumen through which the inner layer comprises a proximal portion and a main portion, and having a folded portion extending along the length of the inner layer, The inner layer includes a tubular strain-relieving layer provided on the proximal portion of the inner layer, To provide a sheath in which at least a portion is configured to locally expand from a non-expandable configuration having a first diameter to an expanded configuration having a second, larger diameter, and then locally contract at least partially back toward the non-expandable configuration. To provide a suppression member positioned on the distal end of the strain-relieving layer, wherein the suppression member restricts the expansion of an adjacent portion including at least one of the inner layer and the strain-relieving layer. Introducing a dilator to the proximal end of the lumen of the sheath, wherein the dilator includes an expansion element provided thereon, The expansion element provided on the expander applies a radially outward force to the lumen, and the expander is advanced through the proximal portion of the inner layer so as to locally expand the inner layer adjacent to the expansion element from a non-expanded configuration to an expanded configuration, wherein the restraining member restricts the expansion of the sheath adjacent to the restraining member. A method comprising heating the aforementioned sheath.

2. The method according to claim 1, wherein the restraining member restricts the unfolding of the folded portion of the inner layer adjacent to the restraining member as the sheath moves from the non-expanded configuration to the expanded configuration while the expander is advancing through the proximal portion of the inner layer.

3. The method according to claim 1, wherein the suppression member is provided over the length of the sheath at a position corresponding to the distal end of the strain-relieving layer, and extends along the length of the strain-relieving layer from the distal end to the proximal end of the strain-relieving layer, and along a second length of the sheath from the distal end of the strain-relieving layer towards the distal end of the sheath.

4. The method according to claim 1, wherein providing the suppressing member on the sheath includes bonding the suppressing member to at least one of the inner layer or the strain-relieving layer.

5. The suppressing member includes at least one of an adhesive or a shrink tube. If the restraining member includes an adhesive, the inner surface of the restraining member contains the adhesive for bonding the restraining member to the sheath. The method according to claim 4, wherein, if the suppressing member includes the shrink tube, bonding the suppressing member to at least one of the inner layer or the strain relief layer provides the suppressing member with a shrink process.

6. Removing the suppression member from the inner layer and the strain relief layer, The release feature is incorporated into a package that is sized and configured to accept the sheath. The method according to claim 1, wherein providing a radially expandable sheath comprises removing the sheath from the package, and removing the sheath from the package further comprises removing the suppressing member from the inner layer and the strain relief layer.

7. The method according to claim 1, wherein advancing the expander through the proximal portion of the inner layer includes advancing the expanding element of the expander toward the distal end of the strain-relieving layer so that the distal end of the strain-relieving layer is expanded.

8. Advancing the expander through the proximal portion of the inner layer includes advancing the expanding element of the expander beyond the distal end of the strain-relieving layer so that the distal end of the strain-relieving layer and a portion of the main body of the inner layer are expanded. The method according to claim 1, wherein extending a portion of the main body beyond the strain-relieving layer causes to at least partially unfold the corresponding length of the folded portion.

9. The aforementioned sheath, An outer layer provided on the inner layer, wherein the outer layer is discontinuous and includes an overlapping portion and a base portion, and the overlapping portion overlaps the base portion, At least a portion of the folded part of the inner layer is positioned between the overlapping portion and the base portion, The strain-relieving layer extends at least partially onto the outer layer, In the non-expandable configuration, the folded portion extends circumferentially across the outer surface of the inner layer and / or outer layer. In the aforementioned extension configuration, the local extension causes the length of the folded portion to be unfolded, at least partially. In the aforementioned expansion configuration, the local expansion of the sheath shifts the length of the overlapping portion circumferentially with respect to the base portion, forming a gap between the longitudinally extending edges of the outer layer. At least a portion of the unfolded portion extends into the gap, The method according to claim 1, wherein the suppressing member limits the expansion of the sheath and the width of the gap adjacent to the suppressing member.

10. Heating the sheath includes heating the sheath at a temperature and duration corresponding to the sterilization process. The method according to claim 1, wherein during the heating, the sheath is not heated to a temperature or for a duration sufficient to bond the layers of the folded portion.

11. It is a sheath system, A radially expandable sheath, A continuous inner layer defining the lumen through it, wherein the inner layer includes a proximal portion, a main portion, and a folded portion extending along the length of the inner layer, A tubular strain-relieving layer provided on the proximal portion of the inner layer, A radially expandable sheath including a restraining member positioned on the distal end of the strain-relieving layer, which restricts the expansion of at least one adjacent portion of the inner layer and the strain-relieving layer, A dilator sized and configured to be received within the lumen of the inner layer, comprising a dilator including an extended dilator shaft and an expansion element provided thereon, At least a portion of the sheath is configured to locally expand from a non-expanded configuration having a first diameter to an expanded configuration having a second, larger diameter in response to a radially outward force applied to the lumen by the expansion element of the expander, and then locally contract at least partially back toward the non-expanded configuration as the expander passes through the lumen. A sheath system in which the suppressing member restricts the expansion of the sheath adjacent to the suppressing member.

12. The system according to claim 11, wherein the restraining member is coupled to the sheath and, when the sheath moves from the non-extended configuration to the extended configuration, the unfolding of the folded portion of the inner layer adjacent to the restraining member is restricted.

13. The restraining member includes a release feature for removing the restraining member from the sheath, which includes at least one of a weakening portion integrated with the restraining member, or a pull tab, and / or a wire. The aforementioned release feature is incorporated into a package sized and configured to receive the sheath. The system according to claim 11, wherein removing the sheath from the package removes the suppression member from the inner layer and the strain relief layer.

14. The system according to claim 11, wherein the expander shaft includes a main body portion adjacent to the proximal end of the expander shaft and a tapered portion extending from the distal end of the expander shaft toward the main body portion, and the expander element is provided on the main body portion and includes a projection extending from the outer surface of the expander shaft.

15. At least a portion of the strain-relieving layer is configured to locally expand from a non-expanded configuration with a first diameter to an expanded configuration with a second, larger diameter, and then locally contract at least partially back to the non-expanded configuration. The system according to claim 11, wherein at least a portion of the strain-relieving layer is configured to locally expand from the non-expanded configuration to the expanded configuration in response to a radially outward force applied to the lumen by the expander, and then locally contract back to the non-expanded configuration as the expander moves within the lumen.

16. The aforementioned sheath, The present invention further includes an outer layer provided on the inner layer and bonded to the inner layer, The strain-relieving layer comprises a material that is harder and / or less elastic than the inner layer and the outer layer, and restricts the expansion of at least one of the inner layer or the outer layer. The system according to claim 11, wherein the strain-relieving layer comprises a material having a higher durometer than the inner layer and / or the outer layer, such that the strain-relieving layer restricts the expansion of at least one of the inner layer or the outer layer.

17. The aforementioned sheath, An outer layer provided on the inner layer, wherein the outer layer is discontinuous and includes an overlapping portion and a base portion, and the overlapping portion overlaps the base portion, At least a portion of the folded part of the inner layer is positioned between the overlapping portion and the base portion, The system according to claim 11, wherein the strain-relieving layer extends at least partially onto the outer layer.

18. In the aforementioned expansion configuration, the local expansion at least partially unfolds the length of the folded portion, forming the unfolded portion of the inner layer. In the aforementioned expansion configuration, the local expansion of the sheath shifts the length of the overlapping portion circumferentially relative to the base portion, forming a gap between the longitudinally extending edges of the outer layer, and at least a portion of the unfolded portion extends into the gap. The system according to claim 17, wherein the suppressing member limits the expansion of the sheath and the width of the gap adjacent to the suppressing member.

19. The system according to claim 11, wherein the overall length of the strain-relieving layer and / or sheath does not change when the sheath and / or strain-relieving layer moves between the non-expanded configuration and the expanded configuration.

20. It is a sheath system kit, A radially expandable sheath, A continuous inner layer defining the lumen through it, wherein the inner layer includes a proximal portion, a main portion, and a folded portion extending along the length of the inner layer, A tubular strain-relieving layer provided on the proximal portion of the inner layer, A radially expandable sheath including a restraining member positioned on the distal end of the strain-relieving layer, which restricts the expansion of the inner layer and at least one adjacent portion of the strain-relieving layer, A dilator sized and configured to be received within the lumen of the inner layer, comprising an extended shaft and an expansion element provided thereon, A tray sized and configured to receive the sheath and the expander, wherein the tray includes a release mechanism coupled to the restraining member, and when the sheath is removed from the tray, the release mechanism holds the restraining member, thereby removing the restraining member from the sheath. At least a portion of the sheath is configured to locally expand from a non-expanded configuration having a first diameter to an expanded configuration having a second, larger diameter in response to a radially outward force applied to the lumen by the expansion element of the expander, and then locally contract at least partially back toward the non-expanded configuration as the expander passes through the lumen. A sheath system kit in which the suppressing member restricts the expansion of the sheath adjacent to the suppressing member.

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