Expandable sheath including reverse bayonet locking hub

Abstract

We provide a sheath locking sleeve. [Solution] A sheath locking system including an introducer locking hub, which includes a hub body defining a locking channel for engaging with a corresponding guide on a sheath locking sleeve. A sheath locking sleeve, which is removably coupled to the introducer locking hub via an engagement between the guide and the locking channel. The sheath locking sleeve is movable between a rotatably and axially movable unlocked position relative to the introducer locking hub and a locked position in which the sheath locking sleeve is axially fixed relative to the introducer locking hub.

Description

Technical Field

[0001] The present 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 via a patient's vasculature.

Background Art

[0002] 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 artificial valves can be delivered to the treatment site using minimally invasive surgical techniques. Percutaneous interventional medical procedures utilize the fact that large blood vessels in the body reach the target destination rather than surgically creating an opening to the target site. There are many types of disease states that can be treated via interventional methods, including coronary artery occlusion, valve replacement (TAVR), and cerebral aneurysms. These techniques involve using wires, catheters, balloons, electrodes, and other thin devices to move along the length of the blood vessel from an access site to a target site. The device has a proximal end that is controlled by a clinician outside the body and a distal end inside the body that is involved in treating the disease state. Percutaneous interventional procedures offer several advantages over open surgical techniques. First, they require a smaller incision site, which reduces not only the risk of injury, bleeding, but also infection. The procedure also causes less damage to tissue, thus shortening the recovery time. Finally, interventional techniques can usually be performed more quickly and with fewer clinicians participating in the procedure, thus reducing the overall cost. In some cases, the need for anesthesia is also eliminated, further speeding up the recovery process and reducing risk.

[0003] A single procedure typically involves the use of several different guidewires, catheters, and balloons to achieve the desired effect. Each tool is inserted and removed sequentially from the access site, one at a time. For example, a guidewire is used to track the correct position within the body. Next, a balloon may be used to dilate a section of the narrowed blood vessel. Finally, an implant may be delivered to the target site. Because catheters are frequently inserted and removed, introducer sheaths are used to protect local anatomical structures and simplify the procedure.

[0004] 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 trauma to the vessel caused by the rough edges of the catheter. An introducer sheath generally has an elongated sleeve that is inserted into the vascular structure, and a housing that includes one or more sealing valves that allow the delivery device to fluidly communicate with the vascular structure with minimal blood loss. Once the introducer sheath is positioned within the vascular structure, the shaft of the delivery device advances through the sheath into the vascular structure, carrying the prosthetic device. Expandable introducer sheaths, formed from highly elastic materials, allow for vascular dilation to occur as the prosthetic device passes through. Expandable introducer sheaths are disclosed in Patent Document 1, entitled “Expandable Sheath for Introducing an Intravascular Delivery Device into the Body,” Patent Document 2, entitled “Expandable Sheath and Method of Use Thereof,” U.S. Patent Application No. 14 / 880,109, entitled “Expandable Sheath,” U.S. Patent Application No. 16 / 407,057, entitled “Expandable Sheath with Elastomer Cross Section,” Patent Document 3, entitled “Expandable Sheath with Elastomer Cross Section,” U.S. Patent Application No. 15 / 997,587, entitled “Expandable Sheath for Introducing an Intravascular Delivery Device into the Body,” and U.S. Patent Application No. 16 / 378,417, entitled “Expandable Sheath,” the disclosures of which are incorporated herein by reference.

[0005] Conventional methods of accessing blood vessels, such as the femoral artery, before introducing a delivery system involve dilating the vessel using multiple dilators or sheaths with progressively increasing diameters. Typically, the introducer is inserted into the sheath during preparation, and then both are inserted into the vessel. Because a smooth transition from introducer to sheath is required, it is essential that the change in introducer diameter occurs distal to the tip of the sheath so that the tip of the sheath fits snugly around the diameter. During insertion of the sheath and introducer, the introducer may move backward within the sheath, potentially displacing the aforementioned snug fit and forming a lip between the tip of the sheath and the smaller outer diameter of the introducer. This lip / gap can cause severe vascular trauma during insertion.

[0006] Furthermore, some procedures, such as transseptal approaches for mitral valve replacement / repair, require prolonged dilation of cardiac tissue incisions and bending / bending of the sheath to access the treatment site, extending procedure time and recovery, and increasing the risk of trauma to blood vessels and cardiac tissue.

[0007] Therefore, there is still a need for further improvements to expandable introducer sheaths for intravascular systems used to implant valves and other prosthetic devices. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent No. 8,790,387 [Patent Document 2] U.S. Patent No. 10,639,152 [Patent Document 3] U.S. Patent No. 10,327,896 [Patent Document 4] U.S. Patent No. 5,411,552 [Patent Document 5] U.S. Patent No. 9,393,110 [Patent Document 6] U.S. Patent No. 8,690,936 [Patent Document 7] U.S. Patent No. 8,790,387 [Patent Document 8] U.S. Patent Application Publication No. 2014 / 0379067 [Patent Document 9] U.S. Patent Application Publication No. 2016 / 0296730 [Patent Document 10] U.S. Patent Application Publication No. 2018 / 0008407 [Overview of the project]

[0009] The sheath locking system disclosed herein includes an introducer locking hub having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal and distal ends, and a locking channel disposed on the hub body; and a sheath locking sleeve detachably coupled to the introducer locking hub, the sheath locking sleeve including a sleeve body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal and distal ends, and a guide disposed on the outer surface of the sleeve body, wherein the guide is movable within the locking channel between an unlocked position in which the sheath locking sleeve is rotatable and axially movable relative to the introducer locking hub and a locked position in which the sheath locking sleeve is axially fixed relative to the introducer locking hub.

[0010] A method for delivering an artificial device to a treatment site is disclosed herein. The method provides an introducer locking hub having an elongated introducer coupled to a hub body of a locking hub, wherein the introducer locking hub includes a locking channel located within the hub body, and advances the sheath locking sleeve to a position adjacent to the distal end of the introducer locking hub such that a guide protruding from the outer surface of the sheath locking sleeve is received within the locking channel opening on the introducer locking hub and the sheath locking sleeve is coupled to an expandable delivery sheath, wherein advancing the sheath locking sleeve to a position adjacent to the distal end of the introducer locking hub advances the introducer axially within the central lumen of the expandable delivery sheath. The procedure includes advancing the introducer locking hub, rotating the introducer locking hub in a first direction relative to the locking sleeve to move the guide along the locking channel to a locked position, inserting the coupled sheath and introducer at least partially into the patient's vascular structure, rotating the introducer locking hub in a second direction relative to the locking sleeve to slide the guide along the locking channel to a unlocked position, disengaging the introducer locking hub from the locking sleeve, withdrawing the introducer from the central lumen of the sheath, advancing the medical device through the central lumen of the sheath, and delivering the medical device to the treatment site through the central lumen of the sheath.

[0011] A method for securing a delivery sheath to an introducer in an artificial heart valve delivery device, comprising providing an introducer locking hub having an elongated introducer coupled to the hub body of a locking hub, wherein the introducer locking hub includes a locking channel located within the hub body, and a guide protruding from the outer surface of the sheath locking sleeve is received in the locking channel opening on the introducer locking hub, and the locking sleeve is coupled to an expandable delivery sheath, adjacent to the distal end of the introducer locking hub. A method comprising: advancing a sheath locking sleeve to a position adjacent to the distal end of an introducer locking hub such that advancing the sheath locking sleeve to a position adjacent to the distal end of an introducer locking hub is equivalent to advancing an introducer axially within the central lumen of an expandable delivery sheath; rotating an introducer locking hub in a first direction relative to a locking sleeve to move a guide along a locking channel to a locked position; and rotating an introducer locking hub in a second direction relative to a locking sleeve to move a guide along a locking channel to an unlocked position.

[0012] An expandable introducer sheath for accommodating a medical device is disclosed herein. The sheath includes a first layer having a central lumen extending axially through it, and a stretchable elastic layer radially outward from the first layer, configured to apply a radial force to the first layer, such that as the medical device passes through the sheath, the diameter of the sheath expands from an initial diameter to an expanded diameter around the medical device, and the sheath elastically returns to its initial diameter due to the radial force applied by the elastic layer as the medical device passes, and the distal tip of the sheath bends away from the longitudinal axis of the sheath.

[0013] A method for controlling the bending / flexing of a delivery sheath is disclosed herein. The method includes providing an extendable introducer sheath with a central lumen extending through it such that the distal tip portion of the sheath is more flexible than the proximal portion of the sheath; applying force to a pull wire coupled to the distal end of the sheath to bend the distal tip portion away from the longitudinal axis of the sheath; and releasing the force on the pull wire to return the distal tip portion toward the longitudinal axis of the sheath.

[0014] A method for controlling the bending / curving of a delivery sheath is disclosed herein. The method includes providing a central lumen extending into an expandable introducer sheath such that the distal tip portion of the sheath is more flexible than the proximal portion of the sheath; inserting a stylet into the central lumen of the sheath such that the stylet includes a curved portion for causing curvature on the sheath; aligning the curved portion of the stylet with the distal tip portion to curve the distal tip portion away from the longitudinal axis of the sheath; and at least partially removing the stylet from the central lumen of the sheath such that the curved portion of the stylet is no longer aligned with the distal tip portion of the sheath and the distal tip portion returns toward the longitudinal axis of the sheath.

[0015] A method for delivering a medical device is disclosed herein. The method includes: inserting a sheath at least partially into a patient's blood vessel; advancing the distal end of the sheath to a first position close to the treatment site; curving the distal end of the sheath; advancing the distal end of the sheath to the treatment site; advancing the medical device to the treatment site through the central lumen of the sheath; locally expanding the sheath from an initial state / diameter to a locally expanded state / diameter by an outward radial force of the medical device; locally contracting the sheath from the locally expanded state to at least partially return to the initial state by an inward radial force, using the elastic properties of the sheath; and delivering the medical device to the treatment site.

[0016] One aspect further includes advancing the distal end of the sheath through the heart tissue of an open-chest patient.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is an elevational view of an expandable sheath, together with an intravascular delivery device for implanting an artificial implant. [Figure 2] FIG. 2 is an elevational view of an expandable sheath including an introducer locking hub, a sheath locking sleeve, and an introducer. [Figure 3] FIG. 3 is an elevational view of the expandable sheath of FIG. 2, together with an intravascular delivery device for implanting an artificial implant. [Figure 4] FIG. 4 is an elevational view of the expandable sheath of FIG. 2, a sheath hub, an introducer locking hub, and a sheath locking sleeve. [Figure 5A] FIG. 5A is a cross-sectional view of the sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2. [Figure 5B] FIG. 5B is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view of the introducer cap, sheath hub, introducer locking hub, and sheath locking sleeve of FIG. 2. [Figure 7] FIG. 7 is a distal end view of the sheath locking sleeve of FIG. 2 and the proximal fluid seal of FIGS. 5A - B. [Figure 8A] FIG. 8A is a first elevational view of the introducer locking hub of FIG. 2 coupled to an introducer. [Figure 8B] FIG. 8B is a second elevational view of the introducer locking hub of FIG. 2 coupled to an introducer. [Figure 8C] FIG. 8C is a distal end view of the introducer locking hub of FIG. 2 coupled to an 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 2A. [Figure 9C] Figure 9C shows the proximal end 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 shows the proximal end of the sheath locking sleeve in Figure 2. [Figure 10D] Figure 10A 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 cross-sectional view of a portion of the expandable sheath shown in Figure 3. [Figure 12] Figure 12 is a magnified view of a portion of the expandable sheath shown in Figure 3. [Figure 13A]Figure 13A is a magnified view of a portion of the expandable sheath of Figure 3 with the outer layer removed for illustrative purposes. [Figure 13B] Figure 13B is a magnified view of a portion of the braided layer of the sheath shown in Figure 3. [Figure 14] Figure 14 is a magnified view of a portion of the expandable sheath from Figure 3, showing the expansion of the sheath as the artificial device advances through it. [Figure 15A] Figure 15A is a side view of the expandable sheath of Figure 3, including the delivery device and implant. [Figure 15B] Figure 15B is a side view of the expandable sheath of Figure 3, including the delivery device and implant. [Figure 15C] Figure 15C is a side view of the expandable sheath of Figure 3, including the delivery device and implant. [Modes for carrying out the invention]

[0018] The following description of specific examples of the concept of the present invention cannot be used to limit the scope of the claims. Other examples, features, aspects, embodiments, and advantages will be apparent to those skilled in the art from the following description. Apparatus and / or methods may have other different and obvious aspects without departing from the spirit of the concept of the present invention. Accordingly, the drawings and description should be considered as illustrative and not restrictive.

[0019] For the purposes of this specification, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The methods, systems, and apparatus described herein should not be construed as limiting in any way. Rather, this disclosure covers all novel and non-obvious features and aspects of the various embodiments disclosed, both individually and in various combinations and subcombinations with one another. The methods, systems, and apparatus disclosed herein are not limited to any specific aspect, feature, or combination thereof, and the methods, systems, and apparatus disclosed herein do not require that any one or more specific advantages exist or problems are solved.

[0020] Features, integers, properties, compounds, chemical parts, or groups described in conjunction with any particular aspect, embodiment, or example of this disclosure are understood to be applicable to any other aspect, embodiment, or example described herein, insofar as they are not incompatible with such other aspects, embodiments, or examples. All features disclosed herein (including the appended claims, abstract, and drawings) and / or all steps of any method or process disclosed herein may 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 the details of any of the aforementioned aspects. This disclosure extends to any novel features or any novel combination of features disclosed herein (including any of the appended claims, abstract, and drawings), or any novel steps or any novel combination of any method or process steps disclosed herein.

[0021] 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 that is said to be incorporated herein by reference but conflicts with any existing definitions, statements, or other disclosure material expressed herein is incorporated only to the extent that no conflict arises between the incorporated material and the existing disclosure material.

[0022] Where used herein and in the appended claims, the singular forms “a,” “an,” and “the” include multiple references unless the context clearly indicates otherwise. Ranges may be expressed herein as for one specific value and / or for another specific value. Where such ranges are expressed, the other aspects include from one specific value and / or up to another specific value. Similarly, where values ​​are expressed as approximations, the use of the preceding “about” will be understood to mean that the specific value forms another aspect. Furthermore, it will be understood that each evaluation item within each range is important both in relation to and independently of other evaluation items.

[0023] The terms "optional" or "optional" mean that the events or circumstances described below may or may not occur, and that the descriptions include examples of events or circumstances that may and may not occur.

[0024] 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.

[0025] As used herein, “axial” or “axial direction” refers to the direction along the longitudinal axis of the sheath.

[0026] Throughout this description and claims, the word “comprise” and its variations such as “comprising” and “comprises” mean “including, but not limited to,” and are not intended to exclude, for example, other additions, components, integers or processes. “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.

[0027] The disclosed embodiment of the expandable sheath allows for the temporary expansion of a portion of the introducer sheath to adapt to the delivery system, and then returns to its original diameter as the device passes, thereby minimizing trauma to the vessel. The disclosed embodiment 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, maintaining a tight fit and smooth transition between the introducer and the distal end of the sheath. Furthermore, the present embodiment can reduce the time required for the procedure and can reduce the risk of longitudinal or radial vascular tearing or plaque detachment because only one sheath is required instead of several different sized sheaths. The embodiment of the expandable sheath can avoid the need for multiple insertions to dilate the vessel.

[0028] This specification discloses an elongated introducer sheath particularly suitable for the delivery of implantable heart valves, such as balloon-inflatable implantable heart valves. Balloon-inflatable implantable heart valves are well known and will not be described in detail here. Examples of such implantable heart valves are described in Patent Documents 4 and 5, both of which are incorporated herein by reference. The expandable introducer sheaths disclosed herein may also be used to deliver self-expanding and mechanically expandable implantable heart valves, stents, or filters, and other types of implantable medical devices. 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 various types of endovascular devices (e.g., stents, stent grafts, balloon catheters for angioplasty procedures, etc.) and other types of delivery devices for placing many types of vascular and non-vascular 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, may be implantable.

[0029] Figure 1 shows an exemplary sheath 8 used with a typical delivery device 10 for delivering an implant 12 or other type of implantable object to a patient. The delivery device 10 may include a maneuverable guide catheter 14 (also called a flex catheter) and a balloon catheter 16 extending through the guide catheter 14. The guide catheter 14 and balloon catheter 16 in the illustrated embodiment 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. The sheath 8 is an elongated, expandable tube that may include a hemostatic valve at the proximal end of the sheath to prevent blood leakage.

[0030] Figure 2 shows the sheath 8 of Figure 1, including a sheath locking system 18 that prevents axial and rotational movement of the introducer 6 relative to the sheath 8. The sheath locking system 18 secures 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. The sheath locking system 18 includes a locking sleeve 28 coupled to the sheath 8 via a sheath hub 20 and an introducer locking hub 30, and the introducer 6. 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 position of the introducer 6 and sheath 8 and preventing movement between them during insertion. As will be described in more detail below, the sheath locking system 18 prevents the introducer 6 from separating from the sheath 8 and prevents the formation of a gap between the introducer 6 and the sheath 8 during insertion, which could cause patient abrasion and unintended fluid flow.

[0031] Figures 2, 5A-5B and 6 show a sheath locking sleeve 28 that connects the introducer locking hub 30 to the sheath hub 20. 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 (Figure 2) in which the locking sleeve 28 is axially fixed relative to the introducer locking hub 30.

[0032] The locking sleeve 28 is shown, for example, in Figures 10A to 10F. The locking sleeve 28 includes an elongated sleeve body 29 having a central lumen 28a that extends longitudinally between the proximal end 29a and the distal end 29b of the sleeve body 29. As provided in Figure 6, the central lumen 28a defines the substantially cylindrical inner surface 29c of the sheath locking sleeve 28. The central lumen 28a has a diameter of at least 0.3 inches. In some embodiments, the diameter is in the range of 0.3 inches to 0.6 inches. A diameter of approximately 0.40 inches is preferred. The distal end 29b of the sleeve body 29 has a functional outer surface 29 that is tapered around the distal end 29b to help position the locking sleeve 28 within the sheath hub 20 and to contact the seal assembly 24 (Figures 5B and 5B). The locking sleeve 28 also has a number of interface diameters 29e that extend radially from the outer surface 29d of the sleeve body 29 around (all or part of) the locking sleeve 28. As shown in Figure 5A, the interface diameters 29e are sized and configured to engage with corresponding recesses and / or slots 48 provided within the sheath hub 20 in order to secure the locking sleeve 28 to the sheath hub 20.

[0033] The locking sleeve 28 includes a guide 31 that protrudes from the outer surface 29f of the locking sleeve 28. The guide 31 engages a locking channel 38 of a corresponding shape with the introducer locking hub 30. The guide 31 extends radially from the outer surface 29f and at least partially around the outer circumference of the outer surface 29f. As shown in Figure 6, the upper surface of the guide 31 does not extend beyond the outer surface of the introducer locking hub 30 when the sheath locking sleeve 28 and the introducer locking hub 30 are coupled. For example, the height of the guide 31 corresponds to the wall thickness of the introducer locking hub 30 adjacent to the guide when the sheath locking sleeve 28 and the introducer locking hub 30 are coupled. In another embodiment, the upper surface of the guide 31 is recessed relative to the outer surface of the introducer locking hub 30. That is, the height of the guide is less than the wall thickness of the introducer locking hub 30. In other embodiments, the height of the guide 31 is greater than the wall thickness of the introducer locking hub 30 so that the upper 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 embodiments, the height / axial length of the guide 31 is between approximately 0.050 inches and approximately 0.10 inches. In some embodiments, the height / axial length of the guide 31 is approximately 0.075 inches.

[0034] As shown in Figures 10D to 10F, the guide 31 is 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 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.

[0035] Generally, the locking sleeve 28 may be formed from polycarbonate, but in other embodiments, 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 (metal, composite material, etc.).

[0036] Figures 8A–8F show an introducer locking hub 30 having an introducer 6 coupled thereto. Examples of introducer sheaths are described, for example, in Patent Documents 6 and 7, the disclosures of which are incorporated herein by reference. As shown 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 28a of the sheath locking sleeve 28, the sheath hub 20, and the central lumen of the sheath 8. As described below, the sheath 8 generally includes a radially expandable tubular structure. The passage of the introducer 6 into the sheath 8 and into the patient's blood vessel causes the blood vessel to radially expand to approximately the diameter of the sheath 8. In other words, the diameter of the central lumen of the sheath 8 is generally approximately the outer diameter of the introducer 6, so that the introducer 6 provides a mechanism for dilating the patient's blood vessels to receive the sheath.

[0037] As shown in Figures 8A-8F, the introducer 6 is formed as an elongated body having a central lumen extending through it. As shown in Figures 5A and 5B, the central lumen of the introducer is aligned with the central lumens of the introducer locking hub 30, the sheath hub 20, and the sheath 8. The introducer 6 is received in a recessed opening 39 provided on the inner surface of the introducer locking hub 30, and the recessed opening 39 is axially aligned with the central lumen 45 of the introducer locking hub 30. The introducer 6 is coupled to the introducer locking hub 30 at the recessed opening 39. In an exemplary system, the introducer 6 has a diameter equivalent to or smaller than the diameter of the recessed opening 39. In some embodiments, the introducer 6 is fixedly coupled to the introducer locking hub 30 at the recessed opening 39. For example, the introducer 6 is coupled to the recessed opening 39 of the introducer locking hub 30 by at least one of press fitting, interlocking fitting, snap fitting, mechanical fasteners, chemical fasteners (e.g., adhesives), welding, thermal processes, and / or any other suitable coupling processes known in the art.

[0038] As described above, the introducer 6 has a central lumen that aligns with the central lumen 45 of the introducer locking hub 30. This joined lumen allows surgical instruments and / or medical devices to pass through to the treatment site. In exemplary systems, and 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 embodiments, the diameter of the central lumen 45 at the distal end of the introducer locking hub 30 is slightly larger than the diameter of the central lumen passing through the introducer 6. The central lumen 45 can also be a tapering portion 41 that decreases between the proximal and distal ends of the introducer locking hub 30 (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.

[0039] Figures 2-6 show the introducer locking hub 30 coupled to the locking sleeve 28. Figures 8A-8F provide the introducer locking hub 30 coupled to the introducer 6. Figures 9A-9F provide multiple diagrams of the introducer locking hub 30. As described above, the introducer 6 is fixedly coupled to the introducer locking hub 30, and the introducer locking hub 30 is coupled to the locking sleeve 28 to fix the position of the introducer 6 relative to the locking sleeve 28 / sheath 8 (axially and rotationally).

[0040] The introducer locking hub 30 includes a hub body 32 having a proximal end 32a and a distal end 32b, 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 includes a cylindrical recessed opening 39 for receiving and holding the introducer 6 and the outer surface 33b. In some embodiments, the recessed opening 39 has a diameter ranging from 0.15 inches to about 0.25 inches. In some embodiments, the recessed opening 39 has a diameter ranging from 0.17 inches to about 0.20 inches. In some embodiments, the recessed opening has a diameter of about 0.194 inches.

[0041] The third (proximal) portion 37 of the introducer locking hub 30 includes a tapered portion 41 of the central lumen 45. The tapered portion 41 defines a frustoconical shape in which the taper / diameter decreases from the proximal end to the distal end of the sheath. The tapered portion 41 is intended to have a minimum diameter of approximately 0.007 inches and a maximum diameter of approximately 0.194 inches.

[0042] As shown in Figures 5A-5B, when the central lumen 28a of the locking sleeve 28 is coupled, it aligns with the central lumen 45 of the introducer locking hub 30. In some embodiments, the central lumen 28a of the locking sleeve 28 is coaxial with the central lumen 45 of the introducer locking hub 30. When coupled, the proximal end of the locking sleeve 28 is received within the central lumen 45 of the introducer locking hub 30. The proximal end surface of the locking sleeve 28 is adjacent to a shoulder 50 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 having a first diameter adjacent to the proximal end of the introducer locking hub 30 and a second portion 54 having a second, larger diameter adjacent to the distal end of the introducer locking hub 30. The recessed opening 39 can be considered either a component of the first portion 52 of the central lumen 45, or a separate component of the central lumen 45 located between the first (proximal) portion 52 and the second (distal) portion 54. When the locking sleeve 28 and the introducer locking hub 30 are coupled, at least a portion of the sleeve body 29 of the sheath locking sleeve 28 is received within the second portion 54 (larger portion) of the central lumen 45 of the introducer locking hub 30. The central lumen 28a of the sheath locking sleeve 28 aligns 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.

[0043] Generally as described above, the locking sleeve 28 is coupled to the introducer locking hub 30 via an engagement between a guide 31 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 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 form a recess or groove on the surface of the introducer locking hub 30, as well as any other feature that can receive and secure the guide 31 protruding from the outer surface of the locking sleeve 28 having the introducer locking hub 30, such as a slot opening, a clip, or any other feature. As shown in Figure 9B, the locking channel 38 secures the sheath locking sleeve 28 to the introducer locking hub 30 and provides an interface for ensuring a fixed axial position between the introducer 6 and the sheath 8.

[0044] The locking channel 38 is formed on the distal end of the introducer locking hub 30. The locking channel 38 includes an opening on the distal end surface that leads to an angled guide portion 40 that transitions into a locking portion 42. The guide portion 40 is configured to orient the guide 31 of the locking sleeve 28 toward the locking portion 42 axially and circumferentially along the side wall of the guide portion 40 as the introducer locking hub 30 and / or the sheath locking sleeve 28 rotates. The locking portion 42 is configured to reliably engage with the guide 31 that fixes 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, the guide portion 40 of the locking channel 38 can 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.

[0045] As shown in Figures 9B and 9D, the locking portion 42 of the locking channel 38 extends at an angle from the end of the guide portion 40. As shown 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 embodiment, the angle between the centerline of the guide portion 40 and the centerline of the locking portion 42 is approximately 120 degrees. In the exemplary system, the locking portion 42 extends around a portion of the outer circumference of the introducer locking hub 30. The locking portion 42 may extend parallel to the distal end of the introducer locking hub 30. 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 embodiment, the length of the guide portion 40 is equal to or less than the length of the locking portion 42.

[0046] The locking portion 42 may include a catch 44 for securing the guide 31 within the locking portion 42 of the locking channel 38 and for forming a partial barrier for the guide 31 within the locking portion 42. As shown in Figure 9B, the catch 44 includes a projection extending from the side wall 42a of the locking portion 42 for removably securing the guide 31 within the locking channel 38. 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.

[0047] The distal end surface 32b of the introducer locking hub 30 may include features for biasing the guide 31 toward the locking channel 38. For example, the distal end of the introducer locking hub 30 may include a tapered surface angled toward the opening of the locking channel 38. As shown in Figure 9B, the distal end 32b of the introducer locking hub 30 includes a first tapered surface (reducing tapered portion 41) angled toward the leading edge of the opening of the locking channel 38 and a second tapered surface 43 angled toward the trailing edge of the opening of the locking channel 38.

[0048] During use, the engagement between the guide 31 and the guide portion 40 of the locking channel 38 is configured to bias the locking sleeve 28 in the proximal axial direction toward the proximal end of the introducer locking hub 30 (towards the locked position) when the sheath locking sleeve 28 rotates in a 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, the engagement between the guide 31 and the locking portion 42 of the locking channel 38 is configured to bias the locking sleeve 28 in the distal axial direction toward the distal end of the introducer locking hub 30 (towards the unlocked position) when the sheath locking sleeve 28 rotates in a second (opposite) axial direction. In the second direction, the guide 31 advances toward the unlocked position away from the locking portion 42 of the locking channel 38. When the guide 31 is in the locked position and is held by the locking portion 42 by the catch 44, rotation in the second direction biases the catch 44 to overcome the opposing force of the catch 44 and move the guide 31 from the locked position to the unlocked position.

[0049] As shown in Figures 8A–9F, the outer surface 33b of the introducer locking hub body 32 includes a gripping mechanism and / or surface used by a physician or technician when operating the introducer locking hub 30. As provided in Figure 9B, the introducer locking hub body 32 may include two recessed gripping surfaces 34 on both sides of the longitudinal axis of the introducer locking hub 30. When the introducer locking hub 30 is viewed from the side, the gripping surfaces 34 define a dogbone / barbell shape relative to the hub body 32, i.e., a shape having a smaller diameter / width central portion and a larger diameter / width end portion. In an exemplary system, the gripping surfaces 34 are provided along at least 40% of the length of the introducer locking hub body 32. In another embodiment, the gripping surfaces 34 are provided along at least 50% of the length of the introducer locking hub body 32.

[0050] Generally, the introducer locking hub 30 can be formed from polycarbonate, but in other embodiments, the introducer locking hub 30 can be formed from rigid plastic or any other material (such as metal or composite material) suitable for providing the locking mechanism for the introducer 6.

[0051] Figures 2-6 show an exemplary sheath hub 20. As described above, the sheath 8 is coupled to the sheath hub 20, which is then removably coupled to the locking sleeve 28. The sheath hub 20 provides housing for the required seal 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.

[0052] The sheath hub 20 further has a receiving slot 48. The receiving slot 48 is an opening that extends around a portion of the diameter of the sheath hub 20 and is sized to receive the interface diameter 29e. The coupling between the receiving slot 48 and the interface diameter 29e of the locking sleeve 28 fixes the locking sleeve 28 and the sheath hub 20 axially and rotationally relative to each other.

[0053] 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 to secure the sheath 8 to the sheath hub 20 by coupling the sheath hub cap 22 to the sheath hub 20. The sheath hub cap 22 is a cylindrical cap having a proximal end and a distal end, with a cap body 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.

[0054] The seal assembly 24, as described above and shown in Figures 5A and 5B, is contained within the sheath hub 20. The seal assembly 24 includes a proximal seal 24a, an intermediate seal 24b, and a distal seal 24c. When assembled, the introducer 6 passes through the seal assembly and extends distally into the sheath 8. The proximal seal 24a, intermediate seal 24b, and distal seal 24c are each formed to prevent unwanted fluid from advancing proximal through the proximal portion of the sheath hub 20 and the seal assembly 24. They are each openable and closable and provide pressure fluctuations to influence the desired fluid flow from a physician or technician.

[0055] As shown in Figure 2, the sheath 8 includes a seal tube 26 / strain relief section. The seal tube 26 is coupled to the distal end of the sheath hub 20, creating a smooth transition surface between the sheath 8 and the sheath hub 20. The frustoconical seal tube 26 body has a proximal end, a distal end, and a central lumen extending longitudinally through it. The seal tube 26 tapers from proximal to distal, such that the diameter of the seal tube 26 at the proximal end is greater than the diameter of the seal tube 26 at the distal end.

[0056] The following describes a method for delivering the prosthetic device to the treatment site so as to eliminate axial movement between the introducer 6 and the sheath 8. Preventing a gap between the introducer 6 and the sheath 8 during insertion reduces the risk of trauma to the patient's vascular structure. Figure 2 shows an exemplary apparatus for delivering the prosthetic device.

[0057] The method includes providing an introducer locking hub 30 having an elongated introducer 6 coupled to a hub body 32 of the introducer locking hub 30. The introducer locking hub 30 includes a locking channel 38 located within the hub body 32 as described above. The sheath locking sleeve 28 advances to a position adjacent to the distal end of the introducer locking hub 30 such that a guide 31 protruding from the outer surface of the sheath locking sleeve 28 is received by the locking channel 38 within the opening. Advance the sheath locking sleeve 28 to a position adjacent to the distal end of the introducer locking hub 30 also includes advancing the introducer 6 axially within the central lumen of the expandable delivery sheath 8.

[0058] Next, the introducer locking hub 30 rotates in a first direction relative to the locking sleeve 28, moving the guide 31 along the locking channel 38 to the locking position. In particular, moving the guide 31 to the locking position involves rotating the introducer locking hub 30 to move the guide 31 along the guide portion 40 of the locking channel 38 toward the locking portion 42. Further rotation of the introducer locking hub 30 directs the guide 31 into the locking portion 42 of the locking channel 38, which is configured to engage securely with the guide 31 and fix the axial position of the introducer locking hub 30 relative to the sheath locking sleeve 28. If the locking channel 38 includes a catch 44, the rotation of the introducer locking hub 30 in the first direction causes the guide 31 to overcome the biasing force of the catch 44, advancing the guide 31 beyond the catch 44 into the locking portion 42, whereupon the catch 44 fixes the guide 31 within the locking portion 42, thereby fixing the axial position of the sheath 8 relative to the introducer 6.

[0059] Next, the combined sheath 8 and introducer 6 are inserted, at least partially, into the patient's vascular structure.

[0060] Once positioned, the introducer locking hub 30 rotates in a second opposite direction relative to the locking sleeve 28. Rotating the introducer locking hub 30 in the second direction causes the guide 31 to slide along the locking channel 38 from the locking portion 42 toward the guide portion 40. In particular, rotating the introducer locking hub 30 in the second direction directs the guide 31 from the locking portion 42 of the locking channel 38 through the guide portion 40, releasing the introducer locking hub 30 from the sheath locking sleeve 28. If the locking channel 38 includes a catch 44, the rotation of the introducer locking hub 30 in the second direction causes the guide 31 to overcome the biasing force of the catch 44 and advance from the locking portion 42 toward the guide portion 40 of the locking channel 38. As a result, the guide 31 slides away from the locking channel 38 toward the unlocked position.

[0061] Next, the introducer locking hub 30 is disengaged from the locking sleeve 28, and the introducer 6 is withdrawn from the central lumen of the sheath 8. With the central lumen of the sheath 8 clear, the medical device (e.g., implant 12) advances through the central lumen of the sheath 8. The medical device (implant 12) is delivered to the treatment site through the central lumen of the sheath 8.

[0062] A method for securing a delivery sheath to an introducer in an artificial heart valve delivery device is disclosed herein. The method includes providing an introducer locking hub 30 having an elongated introducer 6 coupled thereto and including a locking channel 28 located within a hub body 32. The sheath locking sleeve 28 advances to a position adjacent to the distal end of the introducer locking hub 30 such that a guide 31 protruding from the outer surface of the sheath locking sleeve 28 is received within the opening of the locking channel 38. Advancement of the sheath locking sleeve 28 to a position adjacent to the distal end of the introducer locking hub 30 also includes axially advancing the introducer 6 within the central lumen of an expandable delivery sheath 8.

[0063] Next, the introducer locking hub 30 rotates in a first direction relative to the locking sleeve 28, moving the guide 31 along the locking channel 38 to the locking position. In particular, moving the guide 31 to the locking position involves rotating the introducer locking hub 30 to move the guide 31 along the guide portion 40 of the locking channel 38 toward the locking portion 42. Further rotation of the introducer locking hub 30 directs the guide 31 into the locking portion 42 of the locking channel 38, which is configured to engage securely with the guide 31 and fix the axial position of the introducer locking hub 30 relative to the sheath locking sleeve 28. If the locking channel 38 includes a catch 44, the rotation of the introducer locking hub 30 in the first direction causes the guide 31 to overcome the biasing force of the catch 44, advancing the guide 31 beyond the catch 44 into the locking portion 42, whereupon the catch 44 fixes the guide 31 within the locking portion 42, thereby fixing the axial position of the sheath 8 relative to the introducer 6.

[0064] To release the introducer locking hub 30 from the locking sleeve 28, the introducer locking hub 30 rotates in a second opposite direction relative to the locking sleeve 28. By rotating the introducer locking hub 30 in the second direction, the guide 31 moves along the locking channel 38 from the locking portion 42 toward the guide portion 40. In particular, rotating the introducer locking hub 30 in the second direction directs the guide 31 from the locking portion 42 of the locking channel 38 through the guide portion 40, releasing the introducer locking hub 30 from the sheath locking sleeve 28. If the locking channel 38 includes a catch 44, the rotation of the introducer locking hub 30 in the second direction causes the guide 31 to overcome the biasing force of the catch 44 and advance from the locking portion 42 toward the guide portion 40 of the locking channel 38. As a result, the guide 31 slides out of the locking channel 38 to the released position.

[0065] Next, the introducer locking hub 30 is disengaged from the locking sleeve 28, and the introducer 6 can be pulled out from the central lumen of the sheath 8.

[0066] In some procedures, a curved approach to the treatment site is desirable. For example, during a transseptal approach for mitral valve replacement / repair. Mitral valve disease is one of the most common valvular heart diseases and requires surgical intervention to repair or replace this valve. A conventional left laparotomy is the standard approach for most surgeons. However, if the left atrium is small, there are adhesions from previous procedures, there are related surgeries requiring a right laparotomy, and there are surgeries on the beating heart, a transseptal approach can provide better exposure to the mitral valve.

[0067] In the transseptal approach, the right atrium is opened, and a longitudinal incision (approximately 4 cm) is made in the middle of the foramen ovale on the intraacular septum. The septal margin is then pulled back to fully expose the mitral valve. Traditionally, a dilator and / or shunt is required to widen the opening, and the shunt can also be used to close the opening and provide an access point for future procedures. However, a major drawback of the transseptal approach is the risks associated with dilating the incision, maintaining the dilated opening of the foramen ovale, and maintaining the use of a shunt to close the opening. The sheath of this disclosure allows for local and transient dilation of the incision site only during delivery of an artificial device through the incision site.

[0068] As described above, the sheath assembly 8 and introducer 6 can be used to introduce the delivery device 10 and the artificial device (e.g., implant 12) into the patient's body. This specification discloses systems and methods for bending / curving the distal end of the sheath 8 to allow a curved approach to the treatment site. As shown in Figure 3, the introducer device / sheath assembly 8 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 hub 20 can function as a handle for the device. The expandable sheath 8 has a central lumen that guides the passage of the delivery device for the medical device / artificial heart valve. In alternative embodiments, the introducer device / sheath assembly does not need to include the sheath hub 20. For example, the sheath 8 may be an integral part of a component of the sheath assembly, such as a guide catheter. As described above, the sheath 8 may have a naturally non-expanding outer diameter that expands locally as the medical device passes through. In certain embodiments, the expandable sheath 8 may include a plurality of coaxial layers extending along at least a portion of the length of the sheath 8. Exemplary expandable sheaths are described, for example, in U.S. Patent Application No. 16 / 378,417, entitled “Expandable Sheath”, and in U.S. Provisional Patent Application No. 62 / 912,569, entitled “Expandable Sheath”, the disclosures thereof are incorporated herein by reference. The structure of the coaxial layers is described below in more detail with respect to Figures 11–14. Structures that facilitate curvature / bending at the distal end of the sheath 8 are described with reference to Figures 15A–15B.

[0069] Generally, the sheath 8 may include a first tubular layer (inner layer 102) and a second elastic tubular layer 104 radially outside the inner layer 102, the second elastic layer 104 configured to apply a radial force to the inner layer 102. When the medical device (implant 12) passes through the sheath 8 (Figure 15A), the diameter of the sheath 8 temporarily and locally expands from its initial diameter to the expanded diameter around the medical device (implant 12). The sheath 8 elastically returns to its initial diameter due to the radial force applied by the elastic second layer 104 as the medical device (e.g., implant 12) passes through. As shown in Figures 15A-15B, the distal tip 9 of the sheath 8 is configured to bend away from the longitudinal axis of the sheath 8. To facilitate bending, the distal tip 9 can be constructed from a more flexible ovoid foramen than the rest of the sheath 8. In other words, the distal tip 9 may be constructed from a material having lower rigidity than the material of the rest of the sheath 8. The distal tip 9 may also include several features or treatments that facilitate bending. For example, a slit or groove may be cut into the outer surface of the sheath 8 along the distal tip 9. The slit / groove creates a weakened portion and void along its length, causing the sheath 8 to curve along this portion. Various methods for bending the distal tip 9 are described below.

[0070] The distal tip 9 may be formed integrally with the rest of the sheath 8. That is, the distal tip 9 may be constructed from the same coaxial layered material structure as the rest of the sheath 8. In another embodiment, the distal tip 9 may be coupled to the distal end of the sheath 8. For example, the distal tip 9 may be constructed as a separate working channel having different material properties from the sheath 8, coupled to the distal end of the sheath 8. In these embodiments, the distal tip 9 may be fixedly coupled to the distal end of the sheath 8. For example, the distal tip 9 may be coupled to the rest of the sheath 8 by mechanical fasteners, chemical fasteners, thermal processes, or appropriate means for coupling the distal tip 9 to the sheath 8. Similar to the sheath 8, the distal tip 9 expands temporarily and locally from its initial diameter to an expanded diameter around the medical device (e.g., implant 12). For example, as the medical device passes through the central lumen of the distal tip 9, the diameter of the distal tip 9 expands from its initial tip diameter to an expanded tip diameter around the medical device (implant 12). Subsequently, the distal tip 9 elastically returns to its initial tip diameter as the medical device passes through. Similar to the sheath 8, an elastic layer can be provided on the distal tip, and the radial force applied by the elastic layer prompts the distal tip 9 to return to its initial diameter as the medical device (implant 12) passes through.

[0071] In an exemplary system, the sheath 8 may include a pull wire to facilitate bending of the distal tip 9. As shown in Figure 15, the sheath 8 (and distal tip 9) may include a pull wire lumen 11 extending from the distal tip 9 of the sheath to the proximal end of the sheath 8, and a pull wire 13 extending through it. The pull wire lumen 11 can be embedded within the wall thickness of the sheath 8. In another embodiment, the pull wire lumen 11 is provided along the central lumen of the sheath 8. In a further embodiment, the pull wire lumen 11 is provided along the outer surface of the sheath 8. It is further intended that the pull wire 13 may extend through the central lumen of the sheath 8 or along the outer surface of the sheath 8. In these embodiments, a guiding mechanism is provided along the length of the central lumen and / or the outer surface of the sheath 8 to prevent the pull wire 13 from deviating from its intended path along the sheath 8. Regardless of its location (within the wall thickness, within the central lumen, or outside the sheath 8), the pull wire lumen 11 / pull wire 13 is offset laterally from the longitudinal axis of the sheath 8. Generally, the pull wire 13 extends along the side of the sheath 8. The force applied to the pull wire approximates a curved shape at the distal tip 9 of the sheath 8. The tension in the pull wire 13 curves the distal tip 9 of the sheath 8 in a direction corresponding to the pull wire 13. For example, the pull wire 13 may extend along the first side of the sheath 8 (e.g., the right). Applying tension to the pull wire 13 curves the sheath 8 (at the distal tip 9) in a direction corresponding to the first part of the sheath (e.g., a curve to the right away from the longitudinal axis of the sheath 8). Similarly, releasing tension on the pull wire 13 straightens the sheath 8, returning it to its original straight contour.

[0072] The pull wire 13 may be coupled to the distal tip 9 at a coupling point close to the distal end of the sheath. The pull wire may be coupled to the distal end surface of the sheath 8, or at a position close to the distal end surface. In another embodiment, the coupling point of the pull wire is offset from the distal end of the sheath 8. The pull wire may be coupled to the sheath 8 / pull wire lumen 11, but this may be mechanical fasteners (e.g., anchors, clips, pins) and / or chemical fasteners. The pull wire may also be coupled to the sheath / pull wire lumen by a heat treatment process.

[0073] In another embodiment (not shown), a curved stylet can be used to curve the distal tip 9 of the sheath 8. For example, a curved stylet that is movable within the central lumen of the sheath 8 may be provided. The distal end of the stylet may include a curved portion that, when received within the central lumen of the sheath 8, produces the corresponding curve of the sheath 8. The stylet is movable to a final position within the sheath 8 such that the curved portion of the stylet is close to the distal tip 9 of the sheath 8 and the stylet influences the corresponding curve of the distal tip 9. Generally, the stylet may include a central lumen for receiving / passing a guidewire or other medical device.

[0074] Various features of the coaxial layer structure of the sheath 8 are described with reference to Figures 11-14. Referring to Figure 11, the expandable sheath 8 may include an inner layer 102 (also called the inner layer), a second layer 104 positioned around and radially outward of the inner layer 102, a third layer 106 positioned around and radially outward of the second layer 104, and a fourth outer layer 108 (also called the outer layer) positioned around and radially outward of the third layer 106. In the configuration shown, the inner layer 102 can define the lumen 112 of the sheath extending along the central axis 114.

[0075] Referring to Figure 12, when the sheath 8 is in a non-expanded state, the inner layer 102 and / or outer layer 108 can form longitudinally extending folds or creases such that the surface of the sheath includes a number of ridges 126 (also referred to herein as “folds”). The ridges 126 can be spaced apart from each other circumferentially by longitudinally extending valleys 128. When the sheath expands beyond its original diameter D1, the ridges 126 and valleys 128 can become horizontal or incorporated as the surface expands radially and the circumference increases, as described further below. When the sheath folds back to its original diameter, the ridges 126 and valleys 128 can be reformed.

[0076] In certain embodiments, the inner layer 102 and / or the outer layer 108 may include relatively thin layers of polymer material. For example, in some embodiments, the thickness of the inner layer 102 may be 0.01 mm to 0.5 mm, 0.02 mm to 0.4 mm, or 0.03 mm to 0.25 mm. In certain embodiments, the thickness of the outer layer 108 may be 0.01 mm to 0.5 mm, 0.02 mm to 0.4 mm, or 0.03 mm to 0.25 mm.

[0077] In certain examples, the inner layer 102 and / or the outer layer 108 may include a lubricating, low-friction, and / or relatively inelastic material. In certain embodiments, the inner layer 102 and / or the outer layer 108 may include a polymer material 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 polyetheretherketone (PEEK). With respect to the inner layer 102 in particular, such low-friction materials can facilitate the passage of artificial devices through the lumen 112. Other suitable materials for the inner and outer layers may include polytetrafluoroethylene (PTFE), stretched polytetrafluoroethylene (ePTFE), ethylenetetrafluoroethylene (ETFE), nylon, polyethylene, polyetherb-locking amide (e.g., Pebax), and / or any combination of the above. Some embodiments of the sheath 8 may 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. Other materials suitable for lubricating liners may also include those having a coefficient of friction of 0.1 or less, preferably.

[0078] In addition, some embodiments of the sheath 8 may include an external hydrophilic coating on the outer surface of the outer layer 108. Such a hydrophilic coating can facilitate the insertion of the sheath 8 into the patient's blood vessel and reduce potential damage. Examples of suitable hydrophilic coatings include Harmony® Advanced Lubricity Coating and other advanced hydrophilic coatings, available from SurModics, Inc. of Eden Prairie, Minnesota. DSM medical coatings (Koninklijke DSM NV, available from Heerlen, Netherlands) and other hydrophilic coatings (e.g., PTFE, polyethylene, polyvinylidene fluoride) are also suitable for use with the sheath 8. Such a hydrophilic coating can also be included on the inner surface of the inner layer 102 to reduce friction between the sheath and the delivery system, thereby facilitating use and improving safety. In some embodiments, hydrophobic coatings such as perylene may be used on the outer surface of the outer layer 108 or the inner surface of the inner layer 102 to reduce friction.

[0079] In certain embodiments, the second layer 104 may be a braided layer. Figures 13A and 13B show a sheath 8 with the outer layer 108 removed to expose the elastic third layer 106. Referring to Figures 13A and 13B, the braided second layer 104 may include a plurality of members or filaments 110 (e.g., metal or synthetic wire or fiber) braided together. The braided second layer 104 can have any desired number of filaments 110, which can be oriented and braided together 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. The filaments 110A and 110B can be braided together in a biaxial braid such that the filaments 110A oriented along axis A form an angle θ with the filaments 110B oriented along axis B. In certain embodiments, the angle θ may be 5° to 70°, 10° to 60°, 10° to 50°, or 10° to 45°. In the illustrated embodiment, the angle θ is 45°. In other embodiments, the filament 110 may 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 braided layer 104 may extend along the substantial total length L of the sheath 8, or may extend only along a portion of the length of the sheath. In certain embodiments, the filament 110 may be a wire made from a metal (e.g., Nitinol, stainless steel, etc.) or a variety of polymers or polymer composite materials, such as carbon fiber. In certain embodiments, the filament 110 may be circular and may have a diameter of 0.01 mm to 0.5 mm, 0.03 mm to 0.4 mm, or 0.05 mm to 0.25 mm. In other embodiments, the filament 110 may have a flat cross-section with dimensions of 0.01 mm × 0.01 mm to 0.5 mm × 0.5 mm, or 0.05 mm × 0.05 mm to 0.25 mm × 0.25 mm. In one embodiment, the filament 110 having a flat cross-section may have dimensions of 0.1 mm × 0.2 mm. However, other shapes and sizes are also suitable for specific embodiments.When using braided wire, the braiding density can be varied. Some embodiments have a braiding density of 10 to 80 picks per inch and may include 8 wires, 16 wires, or up to 52 wires in various braiding patterns. In other embodiments, 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.

[0080] The third layer 106 may be a stretchable elastic layer (also referred to as an elastic material layer). In certain embodiments, the elastic third layer 106 may be configured to apply a radial force (for example, toward the central axis 114 of the sheath) to the underlying layers 102 and 104 as the sheath 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 encircling pressure to the layers of the sheath beneath the elastic third layer 106 to counteract the expansion of the sheath. The radially inward force is sufficient to cause the sheath to fold radially and return to its unexpanded state after the delivery device has passed through it.

[0081] In the illustrated embodiment, the elastic third layer 106 may 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 layer may include any number of bands depending on the desired properties. The elastic bands 116A and 116B can be made from any of a variety of natural or synthetic elastomers, including silicone rubber, natural rubber, any variety of thermoplastic elastomers, polyurethane, such as polyurethane siloxane copolymer, urethane, plasticized polyvinyl chloride (PVC), styrene-locking copolymer, and polyolefin elastomer. In some embodiments, the elastic layer may include an elastomer material having an elastic modulus of 200 MPa or less. In some embodiments, the elastic third layer 106 may include a material exhibiting an elongation at break of 200% or more, or 400% or more. The elastic third layer 106 may also take other forms, such as a tubular layer containing elastomer material, a mesh, a shrinkable polymer layer such as a heat-shrinkable tube layer, etc. Instead of, or in addition to, the elastic third layer 106, the sheath 8 may also include an elastomer or heat-shrinkable tube layer around the outer layer 108. Examples of such elastomer layers are disclosed in Patent Documents 8, 9, and 10, which are incorporated herein by reference. In other embodiments, the elastic third layer 106 may also be radially outward of the polymer outer layer 108.

[0082] In certain embodiments, 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 when the sheath 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, such that the length L remains substantially constant when the sheath expands and contracts. Where used herein with respect to the length L of the sheath, the term “substantially constant” means that the length L of the sheath increases by 1% or less, 5% or less, 10% or less, 15% or less, or 20% or less. On the other hand, referring 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 when the sheath expands and contracts. This, combined with the longitudinal folds 126 of layers 102 and 108, may allow the lumen 112 of the sheath to expand as the artificial device moves forward through it.

[0083] For example, in some embodiments, the inner layer 102 and the outer layer 108 can 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 108. More specifically, in certain embodiments, the inner layer 102 and the outer layer 108 can be bonded to each other through the spaces between the filaments 110 and / or the spaces between the elastic bands 116 of the braided second layer 104. Layers 102 and 108 can also be joined or bonded together at the proximal and / or distal ends of the sheath. In certain embodiments, layers 102 and 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 108, making it possible to increase or decrease the diameter of the braided second layer 104, and thus the diameter of the sheath. As the angle θ between filaments 110A and 110B changes, the length of the braided second layer 104 may also change. For example, as the angle θ increases, the second braided layer 104 can shrink, and as the angle θ decreases, the second braided layer 104 can lengthen to a degree permitted by the region where layers 102 and 108 are joined. However, since the second braided layer 104 is not bonded to layers 102 and 108, the change in the length of the braided layer with respect to the change in angle θ between filaments 110A and 110B does not result in a significant change in the sheath length L.

[0084] Figure 13 shows the radial expansion of the sheath 8 as the prosthetic device (implant 12) passes through the sheath in the direction of arrow 132 (e.g., distal direction). As the prosthetic device (implant 12) advances through the sheath 8, the sheath can expand and contract to a second diameter D2 corresponding to the size or diameter of the prosthetic device. As the prosthetic device (implant 12) advances through the sheath 8, the prosthetic device can apply a longitudinal force to the sheath in the direction of motion due to the action of frictional contact between the prosthetic device and the inner surface of the sheath. However, as described above, the inner layer 102 and / or outer layer 108 can resist axial elongation so that the length L of the sheath remains constant or substantially constant. This reduces or prevents the braided second layer 104 from lengthening, thereby reducing or preventing compression of the lumen 112.

[0085] On the other hand, the angle θ between filaments 110A and 110B can increase as the sheath expands to a second diameter D2 to accommodate the artificial valve. This can result in a reduction of the braided second layer 104. However, since filament 110 does not engage with or bond to layer 102 or 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. Furthermore, due to the longitudinally extending folds 126 formed in layers 102 and 108, layers 102 and 108 can expand to a second diameter D2 without breaking, despite being relatively thin and relatively inelastic. In this way, the sheath 8 can expand and contract elastically from its original diameter D1 to a second diameter D2, which is larger than diameter D1, without stretching or contracting as the artificial device advances through the sheath. Thus, the force required to push the artificial implant through the sheath is greatly reduced.

[0086] In addition, due to the radial force applied by the elastic third layer 106, the radial expansion of the sheath 8 can be localized to specific portions of the sheath occupied by the prosthetic device. For example, referring to Figure 14, as the prosthetic device (implant 12) moves distally through the sheath 8, the portion of the sheath immediately proximal to the prosthetic device (e.g., implant 12) can fold radially back to its initial diameter D1 under the influence of the elastic third layer 106. Layers 102 and 108 can also buckle as the circumference of the sheath decreases, resulting in the reformation of ridges 126 and valleys 128. This can reduce the size of the sheath required to accommodate a given size prosthetic device. In addition, the transient and localized nature of the expansion reduces trauma to the blood vessel and surrounding tissue into which the sheath is inserted, as only the portion of the sheath occupied by the prosthetic device expands beyond the sheath's original diameter, and the sheath folds back to its initial diameter once the device has passed. This limits the amount of tissue that needs to be stretched to introduce the artificial device, and the amount of time that a given portion of the blood vessel must be widened.

[0087] A method for controlling the bending / curving of a delivery sheath is disclosed herein. The method includes providing an expandable introducer sheath with a central lumen extending through it and a pull wire coupled to the distal end of the sheath. Tension is applied to the proximal end of the pull wire, resulting in a corresponding bending / curving motion of the sheath away from the longitudinal axis of the sheath. When the force is released from the pull wire, the sheath returns toward the longitudinal axis of the sheath. In some sheaths, the distal tip portion includes features that facilitate the curvature of the distal tip portion relative to the rest of the sheath (e.g., constructed from a more flexible material, including surface treatment, and including slots / grooves on the outer surface of the sheath). In these embodiments, only the distal tip portion of the sheath curves in response to the tension applied on the pull wire. In other embodiments, the sheath curves along its entire length.

[0088] Another exemplary method for controlling the bending / curving of a delivery sheath involves providing an expandable introducer sheath with a central lumen extending through it, where the distal tip portion of the sheath is more flexible than the proximal portion. A stylet is inserted into the central lumen of the sheath, and the stylet includes a curved portion for creating a curve on the sheath. When the curved portion of the stylet aligns with the distal tip portion, the distal tip portion is in a direction corresponding to the curve of the stylet. For example, the stylet may include a curved portion having a curve that extends away from the longitudinal axis of the sheath. When the curved portion of the stylet aligns with a more flexible portion of the sheath, the corresponding curvature effect is achieved. In some embodiments, the stylet includes a curved portion that curves away from the longitudinal axis of the sheath, resulting in a corresponding curve within the sheath. Removing the stylet at least partially from the central lumen of the sheath so that the curved portion of the stylet no longer aligns with a more flexible portion would return the sheath to its original curvature.

[0089] A method for delivering a medical device using an articulated introducer sheath is disclosed herein. The method involves at least partially inserting the sheath into the patient's blood vessel. In an exemplary method, the sheath is introduced into the patient via the femoral vein. The distal end of the sheath is then advanced to a first position close to the treatment site. For example, in a transseptal approach for mitral valve repair / replacement, the sheath is advanced through the inferior vena cava into the right atrium. In some embodiments, a guidewire is positioned at the treatment site, and the sheath is advanced over the guidewire.

[0090] The distal end of the sheath is curved to facilitate access to the treatment site. In the case of a transseptal approach for mitral valve replacement, the end of the sheath needs to be curved to access the mitral valve through the foramen oval.

[0091] With the end of the sheath curved, the sheath and / or medical device can be advanced from the primary position (in the right atrium) to the treatment site (of the mitral valve). Access to the treatment site may require creating an opening in the patient's cardiac tissue (e.g., the foramen ovale). In this example, a cutting instrument can be advanced through the sheath to create an opening in the patient's cardiac tissue. The cutting instrument includes, for example, a Brockenbrough-type needle. Using the cutting instrument, the cardiac tissue is incised (e.g., the foramen ovale), the cutting instrument is withdrawn, and the distal end of the sheath is advanced through the opening in the patient's cardiac tissue.

[0092] The medical device (e.g., an implant) advances through the central lumen of the sheath to the treatment site. If the distal end of the sheath is provided through an opening in the patient's cardiac tissue, the advancement of the medical device to the treatment site includes the advancement of the medical device through the opening in the cardiac tissue via the sheath.

[0093] The sheath is locally expanded from its initial state / diameter to a locally expanded state / diameter by a radial force of the medical device oriented outward relative to the inner wall of the central lumen of the sheath. The sheath is then locally contracted from the locally expanded state back to at least partially its initial state by an inward radial force, utilizing the elastic properties of the sheath.

[0094] With the distal end of the sheath positioned at the treatment site, the medical device is deployed beyond the sheath and delivered to the patient. As the distal end of the sheath is delivered through the opening in the patient's cardiac tissue, the opening in the cardiac tissue is expanded by the passing medical device and released toward its initial state upon passage of the implant. Where a typical transseptal approach procedure requires a large incision size and the use of a shunt or access tube to maintain the opening of the foramen ovale, the locally expanding articulated sheath of this disclosure allows for a much smaller incision opening, as only the sheath needs to be inserted into (and maintained within) the opening of the foramen ovale. As a result, the incision size is reduced from approximately 1.5 inches to less than 0.5 inches. Furthermore, since the incision is only temporarily expanded during the passage of the implant and does not need to maintain a large opening (e.g., by a shunt), less stress is placed on the tissue surrounding the opening. Also, because the incision is significantly smaller and a shunt is not required, there is less concern about post-procedural adverse events related to incision closure or leakage around a shunt left in place.

[0095] Exemplary aspects In terms of the processes and compositions described herein, this specification sets forth some of the more specifically described embodiments of this disclosure below. However, these particularly enumerated embodiments should not be construed as having any limiting effect on any different claims, including different or more general teachings set forth herein, or that “specific” embodiments are limited in any way other than the inherent meaning of the language and formulas used literally within them.

[0096] Example 1: An introducer locking hub comprising a hub body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal and distal ends, and a locking channel disposed on the hub body; and a sheath locking sleeve removablely coupled to the introducer locking hub, comprising a sleeve body having a proximal end and a distal end and defining a central lumen extending longitudinally between the proximal and distal ends, and a guide disposed on the outer surface of the sleeve body, wherein the guide is movable within the locking channel between an unlocked position in which the sheath locking sleeve is rotatable and axially movable relative to the introducer locking hub and a locked position in which the sheath locking sleeve is axially fixed relative to the introducer locking hub.

[0097] Example 2: The guide protrudes from the outer surface of the locking sleeve and extends at least partially around the outer circumference of the sheath locking sleeve, in any embodiment of this specification, particularly the system described in Example 1.

[0098] Example 3: Any embodiment of this specification, particularly the systems described in Examples 1-2, wherein the guide includes a cylindrical projection extending from the outer surface of the sheath locking sleeve.

[0099] Example 4: Any embodiment of this specification, particularly the systems described in Examples 1-3, wherein when the sheath locking sleeve and the introducer locking hub are coupled, the upper surface of the guide does not extend beyond the outer surface of the introducer locking hub.

[0100] Example 5: Any embodiment of this specification, particularly the system described in Embodiment 4, wherein the guide has a height corresponding to the wall thickness of the introducer locking hub adjacent to the guide when the sheath locking sleeve and the introducer locking hub are coupled.

[0101] Example 6: Any embodiment of this specification, particularly the systems described in Examples 1 to 3, wherein the upper surface of the guide extends beyond the outer surface of the introducer locking hub when the sheath locking sleeve and the introducer locking hub are coupled.

[0102] Example 7: Any embodiment of this specification, particularly the system described in Embodiment 6, wherein the guide has a height greater than the wall thickness of the introducer locking hub adjacent to the guide when the sheath locking sleeve and the introducer locking hub are coupled.

[0103] Example 8: Any embodiment of this specification, particularly the systems described in Examples 1 to 7, wherein the central lumen of the sheath locking sleeve is aligned with the central lumen of the introducer locking hub.

[0104] Example 9: Any embodiment of this specification, particularly the systems described in Examples 1 to 8, wherein the central lumen of the sheath locking sleeve is coaxial with the central lumen of the introducer locking hub.

[0105] Example 10: Any embodiment of this specification, particularly the systems described in Examples 1 to 9, wherein at least a portion of the sleeve body of the sheath locking sleeve is received within the central lumen of the introducer locking hub.

[0106] Example 11: Any embodiment of this specification, particularly the system described in Example 10, wherein a portion of the sleeve body includes a guide.

[0107] Example 12: Any embodiment of this specification, in particular the system described in Example 10 or 11, wherein a portion of the sleeve body is adjacent to the proximal end of the sheath locking sleeve,

[0108] A system in which, when the sleeve body portion is received within the central lumen of the introducer locking hub, the proximal end surface of the sheath locking sleeve is adjacent to a shoulder provided on the inner surface of the central lumen of the introducer locking hub.

[0109] Example 13: Any embodiment of this specification, particularly the system described in Examples 1 to 12, wherein the central lumen of the introducer locking hub includes a first portion having a first diameter adjacent to the proximal end of the introducer locking hub and a second portion having a second larger diameter adjacent to the distal end of the introducer locking hub, and at least a portion of the sleeve body of the sheath locking sleeve is received within the second portion of the central lumen of the introducer locking hub.

[0110] Example 14: Any embodiment of this specification, particularly the systems described in Examples 1 to 13, wherein the locking channel is formed as at least one of a recess or groove, a slot opening, or a combination thereof on the surface of the introducer locking hub.

[0111] Example 15: Any embodiment of this specification, particularly the systems described in Examples 1 to 14, wherein the locking channel includes a guide portion and a locking portion, the guide portion is configured to orient the guide axially toward the locking portion along the side wall of the guide portion when at least one of the introducer locking hub and the sheath locking sleeve rotates, and the locking portion of the locking channel is configured to reliably engage with the guide that fixes the axial position of the introducer locking hub relative to the sheath locking sleeve.

[0112] Example 16: Any embodiment of this specification, particularly the system described in Embodiment 15, wherein the guide portion of the locking channel extends axially from the distal end of the introducer locking hub toward the proximal end of the introducer locking hub and around the introducer locking hub.

[0113] Example 17: Any embodiment of this specification, particularly the system described in Example 16, wherein the guide portion of the locking channel extends helically around and along the length of the introducer locking hub.

[0114] Example 18: Any embodiment of this specification, particularly the systems described in Examples 15-17, wherein the locking portion of the locking channel extends at an angle from the end of the guide portion.

[0115] Example 19: Any embodiment of this specification, in particular the system described in Example 18, in which the angle between the center line of the guide portion and the center line of the locking portion is greater than 90 degrees.

[0116] Example 20: Any embodiment of this specification, particularly the systems described in Examples 15-19, wherein the locking portion extends around a portion of the outer circumference of the introducer locking hub parallel to the distal end of the introducer locking hub.

[0117] Example 21: Any embodiment of this specification, particularly the systems described in Examples 15-20, wherein the length of the guide portion is greater than the length of the locking portion.

[0118] Example 22: A system according to any embodiment of this specification, particularly Examples 15-21, including a catch in which the locking portion secures the guide within the locking portion of the locking channel.

[0119] Example 23: The catch extends from the side wall of the locking portion toward the center of the locking channel, in any embodiment of this specification, particularly the system described in Example 22.

[0120] Example 24: Any embodiment of this specification, particularly the systems described in Examples 1 to 23, wherein the introducer locking hub includes a second locking channel, and the sheath locking sleeve includes a second guide, the second guide being movable within the second locking channel between an unlocked position and a locked position.

[0121] Example 25: The introducer locking hub includes a third locking channel, and the sheath locking sleeve includes a third guide, the third guide being movable within the third locking channel between an unlocked position and a locked position, as described in any embodiment of this specification, particularly the system described in Embodiment 24.

[0122] Example 26: The distal end of the introducer locking hub includes a tapered surface angled toward the opening of the locking channel, as described in any embodiment of this specification, particularly the systems described in Examples 1 to 25.

[0123] Example 27: Any embodiment of this specification, particularly the systems described in Examples 1 to 26, wherein the distal end of the introducer locking hub includes a first tapered surface angled toward the front edge of the locking channel opening and a second tapered surface angled toward the rear edge of the locking channel opening.

[0124] Example 28: Any embodiment of this specification, particularly the systems described in Examples 1 to 27, wherein the guide is configured to bias the locking sleeve in the proximal axial direction toward the proximal end of the introducer locking hub when the sheath locking sleeve rotates in the first axial direction such that the guide advances toward the locking position toward the locking portion of the locking channel.

[0125] Example 29: Any embodiment of this specification, particularly the systems described in Examples 1 to 28, is configured such that the guide biases the locking sleeve distally axially toward the distal end of the introducer locking hub when the sheath locking sleeve rotates in a second axial direction such that the guide advances toward the unlocked position away from the locking portion of the locking channel.

[0126] Example 30: A second rotation biases the guide against the catch, overcoming the opposing force of the catch that holds the guide within the locking portion of the locking channel, in any embodiment of this specification, in particular the system described in the embodiment.

[0127] Example 31: Any embodiment of this specification, particularly the systems described in Examples 1 to 30, wherein the sheath locking sleeve is securely connectable to the sheath hub, and the sheath hub has an elongated body portion having a central lumen extending through it, and an expandable sheath connected to the distal end of the body portion, and the central lumen of the expandable sheath aligns with the central lumen of the sheath hub, the sheath locking sleeve, and the introducer locking hub.

[0128] Example 32: Any embodiment of this specification, particularly the systems described in Examples 1 to 31, wherein a portion of the locking sleeve axially overlaps with the locking hub when the locking channel engages with the guide.

[0129] Example 33: The introducer locking hub body further includes a gripping surface, as described in any embodiment of this specification, particularly the systems described in Examples 1 to 32.

[0130] Example 34: The gripping surface is the recessed surface of the locking hub body, as described in any embodiment of this specification, particularly the system described in Example 33.

[0131] Example 35: The system according to any embodiment of this specification, particularly the examples 33-34, wherein the gripping surfaces are provided on both sides of the locking hub body.

[0132] Example 36: Any embodiment of this specification, particularly the systems described in Examples 33-35, wherein the gripping surface is provided along at least 50% of the length of the locking hub body.

[0133] Example 37: Any embodiment of this specification, particularly the systems described in Examples 33-36, wherein the gripping surface defines the outer surface of the dogbone shape of the introducer locking hub in cross-section.

[0134] Example 38: Any embodiment of this specification, particularly the systems described in Examples 1 to 37, wherein the locking sleeve is formed from rigid plastic.

[0135] Example 39: Any embodiment of this specification, particularly the systems described in Examples 1 to 38, wherein the locking sleeve is formed from polycarbonate.

[0136] Example 40: Any embodiment of this specification, particularly the systems described in Examples 1 to 39, wherein the locking hub is formed from rigid plastic.

[0137] Example 41: Any embodiment of this specification, particularly the systems described in Examples 1 to 40, wherein the locking hub is formed from polycarbonate.

[0138] Example 42: Any embodiment of this specification, particularly the systems described in Examples 1 to 41, further comprising an elongated sheath member coupled to a sheath locking sleeve, the sheath member extending beyond the distal end of the hub body, the sheath member having a central lumen extending through it, and the central lumen of the sheath member aligning with the central lumen of the sheath locking sleeve.

[0139] Example 43: Any embodiment of this specification, particularly the system described in Example 42, wherein the locking sleeve forms a continuous inner lumen with the lumen of the sheath.

[0140] Example 44: A system according to any embodiment of this specification, particularly the examples 42-43, wherein a sheath member is coupled to a sheath locking sleeve via a sheath hub, the sheath is coupled to the sheath hub, and the sheath hub is coupled to the sheath locking sleeve.

[0141] Example 45: Any embodiment of this specification, particularly the system described in Examples 1 to 44, further comprises an elongated introducer member coupled to an introducer locking hub, the introducer member extending beyond the distal end of the hub body through the central lumen of the sheath locking sleeve, the introducer member having a central lumen extending through it, and the central lumen of the introducer member aligning with the central lumen of the introducer locking hub.

[0142] Example 46: The system according to any embodiment of this specification, in particular the system according to Embodiment 45, wherein the introducer member is positioned within the central lumen of the sheath member.

[0143] Example 47: A system according to any embodiment of this specification, particularly embodiments 45-46, wherein an elongated introducer member is received in a recessed opening provided on the inner surface of the locking hub, and the recessed opening is axially aligned with the central lumen of the locking hub.

[0144] Example 48: The system according to any embodiment of this specification, particularly the examples 45-47, wherein the introducer member is fixedly coupled to the introducer locking hub.

[0145] Example 49: The system according to any embodiment of this specification, particularly the examples 45-48, wherein the introducer member is coupled to the recessed opening of the locking hub by at least one of press fitting, interlocking fitting, snap fitting, mechanical fasteners, welding, and adhesive.

[0146] Example 50: The system described in any example herein, particularly in Examples 45-49, wherein the central lumen of the introducer member has a diameter corresponding to the diameter of the central lumen of the introducer locking hub.

[0147] Example 51: The system according to any embodiment of this specification, particularly the examples 45-50, wherein the central lumen of the introducer member has a diameter smaller than the diameter of the central lumen of the introducer locking hub.

[0148] Example 52: Any embodiment of this specification, particularly the systems described in Examples 45-51, wherein at least a portion of the central lumen of the introducer locking hub has a tapering that decreases between the proximal and distal ends of the hub body.

[0149] Example 53: Any embodiment of this specification, particularly the systems described in Examples 45-52, wherein at least a portion of the diameter of the central lumen of the sheath is the approximate diameter of the introducer, so that the patient's vascular structure can be gently expanded using the sheath and introducer to a diameter corresponding to the outer diameter of the sheath.

[0150] Example 54: A method for delivering an artificial device to a treatment site, comprising providing an introducer locking hub having an elongated introducer coupled to the hub body of a locking hub, wherein the introducer locking hub includes a locking channel located within the hub body, and advancing the sheath locking sleeve to a position adjacent to the distal end of the introducer locking hub such that a guide protruding from the outer surface of the sheath locking sleeve is received within the locking channel opening on the introducer locking hub and the sheath locking sleeve is coupled to an expandable delivery sheath, wherein advancing the sheath locking sleeve to a position adjacent to the distal end of the introducer locking hub is performed by introducing the sheath locking sleeve axially within the central lumen of the expandable delivery sheath A method comprising: advancing the introducer to move it forward; rotating the introducer locking hub in a first direction relative to the locking sleeve to move the guide along the locking channel to a locked position; inserting the coupled sheath and introducer at least partially into the patient's vascular structure; rotating the introducer locking hub in a second direction relative to the locking sleeve to slide the guide along the locking channel to a unlocked position; disengaging the introducer locking hub from the locking sleeve; withdrawing the introducer from the central lumen of the sheath; advancing the medical device through the central lumen of the sheath; and delivering the medical device to the treatment site through the central lumen of the sheath.

[0151] Example 55: Any embodiment of this specification, particularly the method of Embodiment 54, wherein movement of the guide along the locking channel to a locking position includes moving the guide along the guide portion of the locking channel toward the locking portion of the locking channel, wherein the guide portion of the locking channel extends axially from the distal end of the introducer locking hub toward the proximal end of the introducer locking hub and circumferentially around the introducer locking hub, and further rotation of the introducer locking hub is configured to orient the guide toward the locking portion of the locking channel, the locking portion securely engaging with the guide, and fixing the axial position of the introducer locking hub relative to the sheath locking sleeve.

[0152] Example 56: Any embodiment of this specification, particularly the method of Examples 54-55, wherein the locking portion of the locking channel extends at an angle from the end of the guide portion.

[0153] Example 57: Any embodiment of this specification, particularly the method of Examples 54-56, wherein the locking portion includes a catch that secures the guide within the locking portion of the locking channel.

[0154] Example 58: The rotation of the introducer locking hub in a first direction causes the guide to overcome the biasing force of the catch, advancing the guide beyond the catch into the locking portion, and the catch then fixes the guide within the locking portion, thereby fixing the axial position of the sheath relative to the introducer, as described in any embodiment of this specification, particularly the method of Embodiment 57.

[0155] Example 59: The method according to any embodiment of this specification, particularly embodiments 54-58, wherein rotating the introducer locking hub in a second direction causes the guide to move along the locking channel from the locking portion toward the guide portion, and further rotation of the introducer locking hub in the second direction directs the guide toward and toward the locking portion of the locking channel, thereby releasing the introducer locking hub from the sheath locking sleeve.

[0156] Example 60: The method according to any embodiment herein, particularly embodiments 54-59, wherein the rotation of the introducer locking hub in a second direction causes the guide to overcome the biasing force of the catch and advance from the locking portion to the guide portion of the locking channel.

[0157] Example 61: A method for securing a delivery sheath to an introducer in an artificial heart valve delivery device, comprising providing an introducer locking hub having an elongated introducer coupled to the hub body of a locking hub, wherein the introducer locking hub includes a locking channel located within the hub body, and a guide protruding from the outer surface of the sheath locking sleeve is received in the locking channel opening on the introducer locking hub, and the locking sleeve is coupled to an expandable delivery sheath, adjacent to the distal end of the introducer locking hub. A method comprising: advancing a sheath locking sleeve to a position adjacent to the distal end of an introducer locking hub such that advancing the sheath locking sleeve to a position adjacent to the distal end of an introducer locking hub is equivalent to advancing an introducer axially within the central lumen of an expandable delivery sheath; rotating an introducer locking hub in a first direction relative to a locking sleeve to move a guide along a locking channel to a locked position; and rotating an introducer locking hub in a second direction relative to a locking sleeve to move a guide along a locking channel to an unlocked position.

[0158] Example 62: Any embodiment of this specification, particularly the method according to Embodiment 61, wherein movement of the guide along the locking channel to a locking position includes moving the guide along the guide portion of the locking channel toward the locking portion of the locking channel, wherein the guide portion of the locking channel extends axially from the distal end of the introducer locking hub toward the proximal end of the introducer locking hub and circumferentially around the introducer locking hub, and further rotation of the introducer locking hub is configured to orient the guide toward the locking portion of the locking channel, thereby ensuring that the locking portion engages securely with the guide and fixing the axial position of the introducer locking hub relative to the sheath locking sleeve.

[0159] Example 63: Any embodiment of this specification, particularly the method according to Embodiment 61, wherein the guide portion of the locking channel extends axially from the distal end of the introducer locking hub toward the proximal end of the introducer locking hub and around the introducer locking hub.

[0160] Example 64: Any embodiment of this specification, particularly the method of Examples 61-62, wherein the locking portion of the locking channel extends at an angle from the end of the guide portion.

[0161] Example 65: Any embodiment of this specification, particularly the method of Examples 61-63, wherein the locking portion includes a catch that secures the guide within the locking portion of the locking channel.

[0162] Example 66: Any embodiment of this specification, particularly the method of Embodiment 64, wherein rotation of the introducer locking hub in a first direction causes the guide to overcome the biasing force of the catch, advancing the guide beyond the catch into the locking portion, the catch then locking the guide within the locking portion, thereby fixing the axial position of the sheath relative to the introducer.

[0163] Example 67: The method according to any embodiment of this specification, particularly embodiments 61-65, wherein rotating the introducer locking hub in a second direction causes the guide to move along the locking channel from the locking portion toward the guide portion, and further rotation of the introducer locking hub in the second direction directs the guide toward the locking portion of the locking channel and toward the guide portion, thereby releasing the introducer locking hub from the sheath locking sleeve.

[0164] Example 68: Any embodiment of this specification, particularly the method of Examples 61-66, wherein the rotation of the introducer locking hub in a second direction causes the guide to overcome the biasing force of the catch and advance from the locking portion to the guide portion of the locking channel.

[0165] Example 69: An expandable introducer sheath for deploying a medical device, comprising a first layer including a central lumen extending axially through it, and a stretchable elastic layer radially outward from the first layer, configured to apply a radial force to the first layer, wherein as the medical device passes through the sheath, the diameter of the sheath expands from an initial diameter to an expanded diameter around the medical device, and the sheath elastically returns to its initial diameter by the radial force applied by the elastic layer as the medical device passes, and the distal tip of the sheath bends away from the longitudinal axis of the sheath.

[0166] Example 70: Any embodiment of this specification, in particular the expandable sheath described in Example 69, wherein the distal tip of the sheath is more flexible than the rest of the sheath.

[0167] Example 71: An expandable sheath as described in any embodiment of this specification, particularly the embodiments 69-70, wherein the distal tip is constructed from a material having lower rigidity than the material of the rest of the sheath.

[0168] Example 72: An expandable sheath according to any embodiment of this specification, particularly the embodiments described in Examples 69-71, wherein the distal tip is formed integrally with the rest of the sheath.

[0169] Example 73: An expandable sheath as described in any embodiment of this specification, particularly the embodiments described in Examples 69-71, wherein the distal tip is coupled to the rest of the sheath.

[0170] Example 74: An expandable sheath, as described in any embodiment of this specification, particularly the one described in Example 73, wherein the distal tip is fixedly bonded to the rest of the sheath.

[0171] Example 75: An expandable sheath as described in any embodiment of this specification, particularly the one described in Example 73, wherein the distal tip is joined to the rest of the sheath by mechanical fasteners, chemical fasteners, a thermal process, or a combination thereof.

[0172] Example 76: An expandable sheath, as described in any embodiment of this specification, particularly the embodiment 69, wherein the distal tip is radially expandable, and as the medical device passes the distal tip, the diameter of the distal tip expands from the initial tip diameter to the expanded tip diameter around the medical device.

[0173] Example 77: An expandable sheath as described herein, particularly as in Examples 69-76, wherein the distal tip elastically returns to its initial tip diameter due to a radial force applied by the elastic tip layer as it passes through a medical device.

[0174] Example 78: Any embodiment of this specification, particularly the expandable sheath described in Example 77, wherein the elastic tip layer includes an elastic layer extending over the length of the distal tip.

[0175] Example 79: Any embodiment of this specification, particularly the expandable sheaths described in Examples 69-78, wherein the distal tip comprises a first layer and an elastic layer.

[0176] Example 80: An expandable sheath according to any embodiment of this specification, particularly the embodiments described in Examples 69 to 79, further comprising a pull wire lumen extending from the distal tip and proximal end of the sheath, and a pull wire fixed to the distal tip of the sheath and passing through the pull wire lumen, wherein a force applied to the pull wire approximates a curved shape at the distal tip of the sheath.

[0177] Example 81: Any embodiment of this specification, in particular the expandable sheath described in Example 80, wherein the pull wire lumen is laterally offset from the central lumen of the first layer adjacent to the first side surface of the sheath.

[0178] Example 82: Any embodiment of this specification, in particular the expandable sheath described in Example 81, wherein the sheath is curved toward the first side of the sheath.

[0179] Example 83: An expandable sheath according to any embodiment of this specification, particularly the embodiments described in Examples 69-82, further comprising a curved stylet movable within the central lumen of the first layer, wherein the distal end of the stylet includes a curved portion that affects the corresponding curvature of the sheath when it is received within the central lumen of the first layer.

[0180] Example 84: An expandable sheath as described in any embodiment of this specification, particularly the embodiment 83, wherein the curved portion of the stylet is close to the distal tip of the sheath, and the stylet is movable to a final position within the sheath such that the stylet affects the corresponding curvature of the distal tip.

[0181] Example 85: An expandable sheath as described in any embodiment of this specification, particularly the embodiments 83-84, wherein the stylet includes a central lumen extending through it.

[0182] Example 86: An expandable sheath, as described in any embodiment herein, particularly in Examples 69-85, that resists axial elongation of the sheath such that the length of the sheath remains substantially constant when the diameter of the sheath expands from an initial diameter to an expanded diameter.

[0183] Example 87: An expandable sheath according to any embodiment of this specification, particularly Examples 69-86, wherein the first layer is a first polymer layer.

[0184] Example 88: An expandable sheath according to any embodiment of this specification, in particular Example 87, comprising: a braided layer radially outward of a first polymer layer, the braided layer comprising a plurality of filaments braided together; a stretchable elastic layer radially outward of the braided layer; and a second polymer layer radially outward of the elastic layer and bonded to the first polymer layer, such that the braided layer and the elastic layer are encapsulated between the first and second polymer layers, wherein the stretchable elastic layer is radially outward of the braided layer, and the elastic layer is configured to apply radial force to the braided layer and the first polymer layer.

[0185] Example 89: An expandable sheath according to any embodiment of this specification, particularly the one described in Example 88, wherein, as the diameter of the sheath expands from the initial diameter to the expanded diameter, the first and second polymer layers resist axial elongation of the sheath such that the length of the sheath remains substantially constant.

[0186] Example 90: An expandable sheath according to any embodiment of this specification, particularly the embodiments 88-89, wherein the first and second polymer layers include a plurality of longitudinally extending folds when the sheath is at a first diameter.

[0187] Example 91: An expandable sheath according to any embodiment of this specification, in particular the embodiment 90, wherein the longitudinally extending folds form a plurality of circumferentially spaced ridges and a plurality of circumferentially spaced valleys.

[0188] Example 92: An expandable sheath as a medical device passes through the sheath, wherein the ridges and valleys become horizontal and the sheath expands radially, as described in any embodiment of this specification, particularly the expandable sheath described in Example 91.

[0189] Example 93: Any embodiment of this specification, particularly the expandable sheaths described in Examples 88-92, wherein the braided layer comprises a self-shrinking material.

[0190] Example 94: Any embodiment of this specification, particularly the expandable sheaths described in Examples 88-93, wherein the elastic layer comprises one or more elastic bands helically wound on a braided layer.

[0191] Example 95: An expandable sheath as described in any embodiment of this specification, particularly the embodiments described in Examples 88-94, wherein the elastic layer includes two elastic bands wound in opposite helices.

[0192] Example 96: An expandable sheath according to any embodiment of this specification, particularly Examples 88-95, wherein the filaments of the braided layer are movable between the first and second polymer layers, such that the length of the sheath is substantially constant, while the braided layer expands radially as a medical device passes through the sheath.

[0193] Example 97: Any embodiment of this specification, particularly the expandable sheath described in Example 96, wherein the filaments of the braided layer are not engaged with or bonded to the first or second polymer layer.

[0194] Example 98: An expandable sheath according to any embodiment of this specification, particularly Examples 88-97, wherein when the sheath is at a first diameter, the filaments of the braided layer are elastically bent, and the first and second polymer layers are attached to each other by multiple voids between the filaments of the braided layer.

[0195] Example 99: Any embodiment of this specification, particularly the expandable sheath described in Example 98, wherein the first polymer layer and the second polymer layer are attached to each other in multiple voids between the filaments of the braided layer.

[0196] Example 100: An expandable sheath according to any embodiment of this specification, particularly embodiment 69, wherein the first layer includes a thick wall portion integrally connected to a thin wall portion, the thick wall portion having a C-shaped cross-section with an end extending in the direction of a first major axis and an end extending in the direction of a second major axis, the thin wall portion defining an expanded central lumen extending axially through the first layer, the expanded central lumen extending between the end extending in the direction of a first major axis and the end extending in the direction of a second major axis, such that the expanded central lumen is defined by the expanded diameter.

[0197] Example 101: An expandable sheath according to any embodiment of this specification, particularly the one described in Example 100, wherein the first layer extends through the central lumen of the elastic layer, having, in its non-expanded state, an end of the first layer extending in the first longitudinal direction below an end of the inner tubular layer extending in the second longitudinal direction.

[0198] Example 102: An expandable sheath according to any embodiment of this specification, in particular Example 101, wherein the first layer has ends extending in the direction of a first major axis and ends extending in the direction of a second major axis, which are spaced apart and radially expanded in a locally expanded state to a less overlapping state, with a thin wall portion extending between them to form a radially expanded central lumen.

[0199] Example 103: A method for controlling the bending / flexing of a delivery sheath, wherein the method is

[0200] To provide an expandable introducer sheath with a central lumen extending through it, such that the distal tip portion of the sheath is more flexible than the proximal portion of the sheath.

[0201] Applying force to a pull wire connected to the distal end of the sheath, bending the distal tip away from the longitudinal axis of the sheath,

[0202] This includes releasing the force on the pull wire and returning the distal tip portion toward the longitudinal axis of the sheath.

[0203] Example 104: A method for controlling the bending / flexing of a delivery sheath, wherein the method is

[0204] Providing a central lumen extending into an expandable introducer sheath, wherein the distal tip portion of the sheath is more flexible than the proximal portion of the sheath; inserting a stylet into the central lumen of the sheath, wherein the stylet includes a curved portion for causing curvature on the sheath; aligning the curved portion of the stylet with the distal tip portion, causing the distal tip portion to curve away from the longitudinal axis of the sheath; and at least partially removing the stylet from the central lumen of the sheath such that the curved portion of the stylet is no longer aligned with the distal tip portion of the sheath, and the distal tip portion is returned toward the longitudinal axis of the sheath.

[0205] Example 105: A method for delivering a medical device, comprising: inserting a sheath at least partially into a patient's blood vessel; advancing the distal end of the sheath to a first position close to the treatment site; curving the distal end of the sheath; advancing the distal end of the sheath to the treatment site; advancing the medical device to the treatment site through the central lumen of the sheath; locally expanding the sheath from an initial state / diameter to a locally expanded state / diameter by an outward radial force of the medical device; locally contracting the sheath from the locally expanded state to at least partially return to the initial state by an inward radial force, using the elastic properties of the sheath; and delivering the medical device to the treatment site.

[0206] Example 106: Any embodiment of this specification, in particular the method of Example 105, wherein the sheath is introduced into the patient via the femoral vein.

[0207] Example 107: Any embodiment of this specification, particularly the method of Examples 105-106, which includes advancing the distal end of the sheath to the treatment site to create an opening in the patient's cardiac tissue.

[0208] Example 108: Any example of this specification, particularly the method of Example 107, wherein advancing the medical device to the treatment site includes advancing the medical device through an opening in cardiac tissue.

[0209] Example 109: Any embodiment of this specification, particularly the method of Example 108, wherein an opening in the cardiac tissue is expanded by a transit medical device within a sheath.

[0210] Example 110: Any embodiment of this specification, particularly the method of Examples 105-109, further comprising advancing the cutting instrument to the treatment site and using the cutting instrument to form an opening in the cardiac tissue.

[0211] Example 111: Any embodiment of this specification, particularly the method of Example 110, wherein the cutting instrument is a Brockenbrough-type needle.

[0212] Example 112: Any embodiment of this specification, particularly the method of Examples 107-111, wherein the opening includes an incision of the foramen ovale.

[0213] Example 113: Any embodiment of this specification, particularly the method of Examples 105-112, further comprising advancing the distal end of the sheath through the opening of the patient's cardiac tissue.

[0214] Given the many possible ways in which the principles of disclosure 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 this disclosure is defined by the following claims. Accordingly, everything within the scope of these claims and intent is asserted as a disclosure. [Explanation of Symbols]

[0215] 6 ···Introducer 8 ···Sheath 10...Delivery device 12 ···Implants 14 ··· Guide Catheter 16. Balloon catheter 18 ···Sheath locking system 20 ···Sheathhub 22 ···Sheath Hub Cap 24 ···Seal Assembly 26 ···Seal tube 28... Locking sleeve 29 ···Sleeve body 30 ···Introducer Locking Hub

Claims

1. An expandable introducer sheath for deploying medical devices, A first layer including a central lumen extending in the axial direction, The first layer includes an elastic, stretchable layer located radially outward from the first layer, configured to apply a radial force to the first layer. When the medical device passes through the sheath, the diameter of the sheath expands from its initial diameter to an expanded diameter around the medical device. The sheath elastically returns to its initial diameter due to the radial force applied by the elastic layer as it passes through the medical device. An expandable introducer sheath for deploying a medical device, wherein the distal tip of the sheath is curved away from the longitudinal axis of the sheath.

2. The expandable sheath according to claim 1, wherein the distal tip of the sheath is more flexible than the rest of the sheath.

3. The distal tip of the sheath and the pull wire lumen extending from the proximal end of the sheath, The present invention further includes a pull wire fixedly coupled to the distal tip of the sheath and passing through the pull wire lumen, The expandable sheath according to claim 1 or 2, wherein the force applied to the pull wire approximates a curved shape at the distal tip of the sheath.

4. The expandable sheath according to any one of claims 1 to 3, further comprising a curved stylet movable within the central lumen of the first layer, wherein the distal end of the stylet includes a curved portion that affects the corresponding curvature of the sheath when received within the central lumen of the first layer.

5. The expandable sheath according to claim 4, wherein the curved portion of the stylet is close to the distal end of the sheath, and the stylet is movable to a final position within the sheath such that the stylet affects the corresponding curvature of the distal end.

6. A braided layer located radially outward of the first polymer layer, comprising a plurality of filaments braided together, A stretchable elastic layer is provided on the radially outer side of the braided layer, The present invention further includes a second polymer layer located radially outward of the elastic layer and bonded to the first polymer layer, such that the braided layer and the elastic layer are encapsulated between the first and second polymer layers. The expandable sheath according to claim 5, wherein the stretchable elastic layer is located radially outside the braided layer, and the elastic layer is configured to apply radial force to the braided layer and the first polymer layer.

7. The expandable sheath according to claim 6, wherein when the diameter of the sheath expands from the initial diameter to the expanded diameter, the first and second polymer layers resist axial elongation of the sheath such that the length of the sheath remains substantially constant.

8. The expandable sheath according to claim 6 or 7, wherein the first and second polymer layers include a plurality of longitudinally extending folds when the sheath is at the first diameter.

9. The expandable sheath according to claim 8, wherein the longitudinally extending folds form a plurality of circumferentially spaced ridges and a plurality of circumferentially spaced valleys.

10. An expandable sheath according to any one of claims 6 to 9, wherein the filaments of the braided layer are movable between the first and second polymer layers such that the length of the sheath is substantially constant, while the braided layer expands radially as the medical device passes through the sheath.

11. The expandable sheath according to any one of claims 6 to 10, wherein the filaments of the braided layer are elastically bent when the sheath is at the first diameter, and the first and second polymer layers are attached to each other in a plurality of gaps between the filaments of the braided layer.

12. The expandable sheath according to claim 11, wherein the first layer includes a thick wall portion integrally connected to a thin wall portion, the thick wall portion having a C-shaped cross-section with an end extending in the direction of a first major axis and an end extending in the direction of a second major axis, the thin wall portion defining an expanded central lumen extending axially through the first layer, the expanded central lumen extending between the end extending in the direction of the first major axis and the end extending in the direction of the second major axis so as to be defined by the expanded diameter.

Images