Skirt assembly for an implantable prosthetic valve

Abstract

An implantable prosthetic valve includes an annular frame radially expandable from a radially compressed state to a radially expanded state.SOLUTION: The frame includes an inflow end, an outflow end, and a longitudinal axis extending from the inflow end to the outflow end. The prosthetic valve also includes a plurality of leaflets arranged to regulate the flow of blood from the inflow end to the outflow end of the frame, and a skirt assembly. The skirt assembly includes a laminate having a fiber layer sandwiched between a first encapsulation layer and a second encapsulation layer. The first and second encapsulation layers are made of an elastomer, the fiber layer includes a first set of yarns and a second set of yarns interlaced with the first set of yarns, and the first set of yarns and the second set of yarns are non-perpendicular and non-parallel to the longitudinal axis.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Application No. 62 / 931,304, filed November 6, 2019, which is incorporated herein by reference.

[0002] The present disclosure relates to embodiments of prosthetic valves for implantation in a body vessel, such as a native heart valve annulus. [Background technology]

[0003] The human heart can suffer from a variety of valvular diseases. These valvular diseases can cause significant cardiac dysfunction, ultimately necessitating replacement of the natural valve with a prosthetic valve. There are many known prosthetic valves and many known methods for implanting these prosthetic valves in humans.

[0004] Using various surgical techniques, diseased or damaged valves can be replaced or repaired. Due to stenosis and other valvular heart diseases, thousands of patients undergo surgery each year to replace their defective natural heart valves with prosthetic valves. Another somewhat drastic method for treating defective valves is through repair or reconstruction, which is typically used for minimally calcified valves. The problem with surgical treatment is the significant risks posed to patients with these chronic diseases, with high morbidity and mortality rates associated with surgical repair.

[0005] When a native valve is replaced, surgical implantation of a prosthetic valve typically requires open-heart surgery, in which the heart is stopped and the patient is placed on cardiopulmonary bypass (a so-called "heart-lung machine"). In one common surgical procedure, the diseased native valve leaflets are removed and a prosthetic valve is sutured to the surrounding tissue at the annulus. Due to the trauma associated with the procedure and the duration of the extracorporeal blood circulation involved, some patients do not survive the surgical procedure or die shortly thereafter. It is well known that the risks to the patient increase with the length of time required for extracorporeal circulation. Due to these risks, a significant number of patients with defective native valves are deemed inoperable because their condition is too weak to tolerate the procedure. According to some estimates, more than 50% of subjects over the age of 80 who suffer from valvular stenosis are unable to undergo surgery for valve replacement.

[0006] Due to the drawbacks associated with traditional open-heart surgery, percutaneous and minimally invasive surgical approaches have attracted significant attention. In one technique, prosthetic valves are configured to be implanted in a much less invasive procedure via catheterization. For example, U.S. Patent Nos. 5,411,522 and 6,730,118, which are incorporated herein by reference, describe collapsible transcatheter heart valves that can be percutaneously introduced in a compressed state on a catheter and expanded to a desired location by balloon inflation or the use of a self-expanding frame or stent.

[0007] Known prosthetic valves include a frame to which valve structures (e.g., leaflets) are attached, an inner skirt secured to the inside of the frame, and, optionally, an outer skirt secured to the outside of the frame. The inner skirt can serve several functions. For example, the inner skirt can prevent (or reduce) paravalvular leakage, secure the leaflets to the frame, and function as a sealing member to protect the leaflets from damage caused by contact with the frame during crimping and valve actuation cycles. The outer skirt, in cooperation with the inner skirt, can further reduce or avoid paravalvular leakage after implantation of the valve. The inner skirt desirably comprises a tough, tear-resistant material such as polyethylene terephthalate (PET), although various other synthetic or natural materials can be used.

[0008] The inner and outer skirts are often secured to the frame by suturing or stitching the fabric of each skirt to the frame. When the inner skirt is suturing to the frame, the leaflets may be exposed to the sutures. During the valve's working cycle, repeated contact between the leaflets and the exposed sutures, as well as contact between the leaflets and the skirt fabric, can cause leaflet wear. Therefore, improvements to prosthetic valve skirts are desirable. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent No. 6,730,118 [Patent Document 2] US Patent Application Publication No. 2012 / 0123529 [Patent Document 3] US Patent Application Publication No. 2016 / 0317305 [Patent Document 4] US Patent Application Publication No. 2014 / 0209238 [Patent Document 5] U.S. Patent No. 7,993,394 [Patent Document 6] US Patent Application Publication No. 2018 / 0206982 [Patent Document 7] US Patent Application Publication No. 2019 / 0192296 [Patent Document 8] U.S. Patent Application Serial No. 16 / 521,226 Summary of the Invention

[0010] FIELD OF THE DISCLOSURE The present disclosure relates to methods and devices relating to prosthetic valves, such as prosthetic heart valves.

[0011] In one exemplary embodiment, an implantable prosthetic valve may include an annular frame radially expandable from a radially compressed state to a radially expanded state. The frame may have an inflow end, an outflow end, and a longitudinal axis extending from the inflow end to the outflow end. The prosthetic valve may also include a plurality of leaflets arranged to regulate blood flow from the inflow end to the outflow end of the frame, and a skirt assembly. The skirt assembly may include a laminate having a textile layer sandwiched between a first encapsulation layer and a second encapsulation layer. The first and second encapsulation layers are made of an elastomer, and the textile layer includes a first set of threads and a second set of threads interwoven with the first set of threads, the first and second sets of threads being non-perpendicular and non-parallel to the longitudinal axis.

[0012] In some embodiments, the fibrous layer may have a weave density of less than 150 ppi.

[0013] In some embodiments, the fibrous layer may have a weave density of 50 ppi or less.

[0014] In some embodiments, the fibrous layer may have a weave density of about 30 to about 50 ppi.

[0015] In some embodiments, the skirt assembly may include an outer skirt attached to the outer surface of the frame.

[0016] In some embodiments, the skirt assembly may have an inner skirt attached to the inner surface of the frame.

[0017] In some embodiments, the textile layer may be a braided layer.

[0018] In some embodiments, the fibrous layer may be a woven layer.

[0019] In some embodiments, the fibrous layer may be a knit layer.

[0020] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle ranging from 20 to 70 degrees relative to the longitudinal axis of the frame.

[0021] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

[0022] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

[0023] In some embodiments, the threads of the first and second thread sets can be oriented at a 45 degree angle relative to the longitudinal axis of the frame.

[0024] In some embodiments, the yarns of the first and second yarn sets can have from about 10 to about 50 filaments per yarn.

[0025] In some embodiments, the yarns of the first and second yarn sets can have about 20 filaments per yarn.

[0026] In some embodiments, the filaments of the yarn may have a thickness ranging from about 8 microns to about 16 microns.

[0027] In some embodiments, the filaments of the yarn may have a thickness of about 10 microns.

[0028] In some embodiments, at least some of the threads in the first and second sets of threads can be textured so that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are straightened out in an untwisted or uncoiled state when the prosthetic valve is in a radially compressed state.

[0029] In some embodiments, the fibrous layer may include leno yarns.

[0030] In some embodiments, the first and second yarn sets can include a first type of yarn and a second type of yarn, and the first type of yarn can be less elastic or inelastic than the second type of yarn.

[0031] In some embodiments, the textile layer may include a third set of yarns extending axially and braided together with the first set of yarns and the second set of yarns to form a triaxial braid.

[0032] In some embodiments, the third set of threads may be made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

[0033] In some embodiments, the third set of threads can be textured so that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

[0034] In some embodiments, when the prosthetic valve is in a radially compressed state, the skirt assembly can be axially elongated to at least 40% of its initial length when the prosthetic valve is in a radially expanded state.

[0035] In another exemplary embodiment, an implantable prosthetic valve may include an annular frame radially expandable from a radially compressed state to a radially expanded state. The frame may include an inflow end and an outflow end. The prosthetic valve may also include a plurality of leaflets arranged to regulate blood flow from the inflow end to the outflow end of the frame, and an outer skirt attached to the outer surface of the frame. The outer skirt may include a laminate having a textile layer sandwiched between a first encapsulation layer and a second encapsulation layer. The first and second encapsulation layers may be made of an elastomer, and the textile layer may include a first set of threads and a second set of threads interwoven with the first set of threads. The outer skirt may have a first axial length when the prosthetic valve is in the radially expanded state and a second axial length when the prosthetic valve is in the radially compressed state. The second axial length may be 40% greater than the first axial length.

[0036] In some embodiments, the outer skirt can be configured to fit snugly with the frame such that the outer skirt contacts the outer surface of the frame when the prosthetic valve is in a radially expanded state.

[0037] In some embodiments, the first set of threads and the second set of threads can each be parallel to corresponding struts of the frame to which the outer skirt is connected when the prosthetic valve is in a radially expanded state.

[0038] In some embodiments, the first and second sets of threads can be non-perpendicular and non-parallel to a longitudinal axis of the frame extending from the inflow end to the outflow end.

[0039] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle ranging from 20 to 70 degrees relative to the longitudinal axis of the frame.

[0040] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

[0041] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

[0042] In some embodiments, the threads of the first and second thread sets can be oriented at a 45 degree angle relative to the longitudinal axis of the frame.

[0043] In some embodiments, the fibrous layer may have a weave density of less than 150 ppi.

[0044] In some embodiments, the fibrous layer may have a weave density of 50 ppi or less.

[0045] In some embodiments, the fibrous layer may have a weave density of about 30 to about 50 ppi.

[0046] In some embodiments, at least some of the threads in the first and second sets of threads can be textured so that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are straightened out in an untwisted or uncoiled state when the prosthetic valve is in a radially compressed state.

[0047] In some embodiments, the first and second yarn sets can include a first type of yarn and a second type of yarn, and the first type of yarn can be less elastic or inelastic than the second type of yarn.

[0048] In some embodiments, the textile layer may include a third set of yarns extending axially and braided together with the first set of yarns and the second set of yarns to form a triaxial braid.

[0049] In some embodiments, the third set of threads may be made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

[0050] In some embodiments, the third set of threads can be textured so that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

[0051] Certain embodiments of the present disclosure also relate to a method of assembling a prosthetic valve. The method may include attaching a skirt assembly to an annular frame and attaching a plurality of leaflets to the annular frame. The frame may be radially expandable from a radially compressed state to a radially expanded state. The leaflets may be configured to regulate blood flow from the inflow end to the outflow end of the frame. The skirt assembly may include a laminate having a fabric layer sandwiched between a first encapsulation layer and a second encapsulation layer. The first and second encapsulation layers may be made of an elastomer, and the fabric layer may include a first set of threads and a second set of threads interwoven with the first set of threads. The outer skirt may have a first axial length when the prosthetic valve is in the radially expanded state and a second axial length when the prosthetic valve is in the radially compressed state. The second axial length may be at least 40% of the first axial length.

[0052] In some embodiments, the skirt assembly can include an inner skirt. Attaching the plurality of leaflets to the annular frame can include attaching the inner skirt to an inner surface of the frame and further sewing the plurality of leaflets to the inner skirt.

[0053] In some embodiments, the skirt assembly may include an outer skirt, and the act of attaching the skirt assembly to the annular frame may include placing the outer skirt around an outer surface of the frame and sewing the outer skirt to selected posts of the frame.

[0054] In some embodiments, the method may further include forming a laminate by forming a first encapsulation layer by electrospinning, disposing a fiber layer on the first encapsulation layer, and forming a second encapsulation layer on the fiber layer by electrospinning.

[0055] In some embodiments, the method may further include forming a laminate by immersing the fibrous layer in a liquefied polymeric material and then curing the liquefied polymeric material.

[0056] In some embodiments, the method may further include preparing the fiber layer such that the first set of threads and the second set of threads are non-perpendicular and non-parallel to a longitudinal axis of the frame extending from the inflow end to the outflow end.

[0057] In some embodiments, preparing the fibrous layer may include weaving a first set of yarns and a second set of yarns at a selected angle relative to the top and bottom edges of the fabric.

[0058] In some embodiments, preparing the fibrous layer may include cutting diagonally from a fabric in which the yarns extend perpendicular to the edges of the fabric.

[0059] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle ranging from 20 to 70 degrees relative to the longitudinal axis of the frame.

[0060] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

[0061] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

[0062] In some embodiments, the threads of the first and second thread sets can be oriented at a 45 degree angle relative to the longitudinal axis of the frame.

[0063] In some embodiments, the fibrous layer may have a weave density of less than 150 ppi.

[0064] In some embodiments, the fibrous layer may have a weave density of 50 ppi or less.

[0065] In some embodiments, the fibrous layer may have a weave density of about 30 to about 50 ppi.

[0066] In some embodiments, the textile layer may include a third set of yarns extending axially and braided together with the first set of yarns and the second set of yarns to form a triaxial braid.

[0067] In some embodiments, the third set of threads can be made of an elastomer configured to stretch axially when the prosthetic valve changes from a radially expanded state to a radially compressed state.

[0068] In some embodiments, the third set of threads can be textured so that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

[0069] Certain embodiments of the present disclosure relate to a method of assembling a prosthetic valve, including mounting a plurality of leaflets to an annular frame that is radially expandable from a radially compressed state to a radially expanded state, and a method of attaching a skirt assembly to the annular frame. The frame may have an inflow end, an outflow end, and a longitudinal axis extending from the inflow end to the outflow end. The plurality of leaflets may be configured to regulate blood flow from the inflow end to the outflow end of the frame. The skirt assembly may include a laminate having a fabric layer sandwiched between a first encapsulation layer and a second encapsulation layer. The first and second encapsulation layers may be made of an elastomer, and the fabric layer may include a first set of threads and a second set of threads interwoven with the first set of threads. The first set of threads and the second set of threads may be non-perpendicular and non-parallel to the longitudinal axis.

[0070] In some embodiments, the fibrous layer may have a weave density of less than 150 ppi.

[0071] In some embodiments, the fibrous layer may have a weave density of 50 ppi or less.

[0072] In some embodiments, the fibrous layer may have a weave density of about 30 to about 50 ppi.

[0073] In some embodiments, the skirt assembly may include an outer skirt attached to the outer surface of the frame.

[0074] In some embodiments, the skirt assembly may include an inner skirt attached to an inner surface of the frame.

[0075] In some embodiments, the textile layer may be a braided layer.

[0076] In some embodiments, the fibrous layer may be a woven layer.

[0077] In some embodiments, the fibrous layer may be a knit layer.

[0078] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle ranging from 20 to 70 degrees relative to the longitudinal axis of the frame.

[0079] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

[0080] In some embodiments, the threads of the first and second sets of threads may be oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

[0081] In some embodiments, the threads of the first and second thread sets can be oriented at a 45 degree angle relative to the longitudinal axis of the frame.

[0082] In some embodiments, the yarns of the first and second yarn sets can have from about 10 to about 50 filaments per yarn.

[0083] In some embodiments, the yarns of the first and second yarn sets can have about 20 filaments per yarn.

[0084] In some embodiments, the filaments of the yarn may have a thickness ranging from about 8 microns to about 16 microns.

[0085] In some embodiments, the filaments of the yarn may have a thickness of about 10 microns.

[0086] In some embodiments, at least some of the threads in the first and second sets of threads can be textured to retain a twisted or coiled state when the prosthetic valve is in a radially expanded state and to straighten out in an untwisted or uncoiled state when the prosthetic valve is in a radially compressed state.

[0087] In some embodiments, the fibrous layer may include leno yarns.

[0088] In some embodiments, the first and second yarn sets can include a first type of yarn and a second type of yarn, and the first type of yarn can be less elastic or inelastic than the second type of yarn.

[0089] In some embodiments, the textile layer may include a third set of yarns extending axially and braided together with the first set of yarns and the second set of yarns to form a triaxial braid.

[0090] In some embodiments, the third set of threads may be made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

[0091] In some embodiments, the third set of threads can be textured such that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when said prosthetic valve is in a radially compressed state.

[0092] In some embodiments, when the prosthetic valve is in a radially compressed state, the skirt assembly can be axially elongated to at least 40% of its initial length when the prosthetic valve is in a radially expanded state. [Brief explanation of the drawings]

[0093] [Figure 1] 1 shows a side view of an exemplary embodiment of an implantable prosthetic valve. [Figure 2] 2 shows a top view of the prosthetic valve of FIG. 1. [Figure 3] 2 illustrates an exemplary frame for the prosthetic valve of FIG. 1. [Figure 4] 4 shows the frame shown in FIG. 3 in a flattened state. [Figure 5] 5 shows a cross-sectional view of the prosthetic valve of FIG. 1 taken along line 5-5 of FIG. 1. [Figure 6] 2 illustrates the formation of a first covering member onto a mandrel according to an exemplary process for making the inner skirt of the prosthetic valve of FIG. 1. [Figure 7] 7 illustrates the placement of a fabric layer onto the first covering member shown in FIG. 6 according to an exemplary process for creating an inner skirt. [Figure 8] 8 illustrates the placement of multiple masks onto the fabric layer shown in FIG. 7 according to an exemplary process for creating an inner skirt. [Figure 9] 9 illustrates the formation of a second covering member on the fabric layer with the mask shown in FIG. 8 according to an exemplary process for creating an inner skirt. [Figure 10] 10 illustrates the removal of the mask after forming the second covering member shown in FIG. 9 according to an exemplary process for creating an inner skirt. [Figure 11] 1 shows a cross section of a portion of an inner skirt having a window on one side of the inner skirt exposing the underlying woven fabric. [Figure 12] The window shown in Figure 11 illustrates the step of threading the suture through the fabric. [Figure 13] 12 illustrates the step of suturing the inner skirt shown in FIG. 11 to the adjacent struts of the prosthetic valve frame. [Figure 14] 1 shows a perspective view of a prosthetic valve according to another embodiment. [Figure 15] 15 shows a cross-sectional view of the prosthetic valve of FIG. 14 taken along line 15-15 of FIG. 14. [Figure 16A] 1 shows two interwoven thread sections in the skirt when the skirt is in a relaxed state (corresponding to the radially expanded state of the prosthetic valve) and an axially stretched state (corresponding to the radially compressed state of the prosthetic valve). [Figure 16B] 1 shows two interwoven thread sections in the skirt when the skirt is in a relaxed state (corresponding to the radially expanded state of the prosthetic valve) and an axially stretched state (corresponding to the radially compressed state of the prosthetic valve). [Figure 17] 16 shows a cross section of a braided layer for the outer skirt of the prosthetic valve of FIGS. 14 and 15, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0094] 1 and 2 show two different views of a prosthetic valve 10, according to one embodiment. The illustrated valve is adapted to be implanted in the native aortic valve annulus, but in other embodiments, it may be adapted to be implanted in other native valve annulus of the heart. The valve 10 may have several major components: a stent or frame 12, a valve structure 14, and a skirt assembly 15. The skirt assembly 15 may include an inner skirt 16 and, optionally, an outer skirt 18.

[0095] The valve structure 14 (or leaflet structure) includes three leaflets 40 (although a greater or lesser number of leaflets may be used), collectively forming a leaflet structure that may be arranged to collapse (constrict) into a tricuspid valve arrangement. The valve structure 14 is configured to allow blood to flow through the prosthetic valve 10 in a direction from the inlet end 48 of the prosthetic valve to the outlet end 50 of the prosthetic valve, and further to block blood flow through the prosthetic valve in a direction from the outlet end 50 to the inlet end 48.

[0096] Each leaflet 40 desirably has a curved, generally U-shaped inlet or cusp 52. In this manner, the inlet edge of the valve structure 14 has a contoured, curved, scalloped shape. Forming the leaflets in this scalloped shape reduces stress on the leaflets, thereby improving valve durability. Furthermore, the scalloped shape eliminates or at least minimizes folds and ripples that can cause premature calcification in the belly of each leaflet (the central region of each leaflet). The scalloped shape also reduces the amount of tissue material used to form the leaflet structure, thereby allowing for a smaller, more uniform crimp profile at the inflow end of the valve. The leaflets 40 may be formed from pericardial tissue (e.g., bovine pericardial tissue), a biocompatible synthetic material, or various other suitable natural or synthetic materials known in the art and described in U.S. Patent No. 6,730,118, incorporated herein by reference.

[0097] The bare frame 12 is shown in Figure 3. In the illustrated embodiment, the frame 12 has an annular shape defining an inlet end 54 and an outlet end 56 and includes a plurality of struts (or frame members). The frame 12 may be formed with a plurality (three in the illustrated embodiment) of circumferentially spaced slots or commissure windows 20 adapted to attach the commissures 58 of the valvular structure 14 to the frame, as fully described in U.S. Patent Application Publication No. 2012 / 0123529, which is incorporated herein by reference.

[0098] Frame 12 may be made of any of a variety of suitable plastically expandable materials (e.g., stainless steel, etc.) or self-expanding materials (e.g., nitinol), as known in the art. If constructed of a plastically expandable material, frame 12 (and thus valve 10) may be crimped into a radially compressed state on a delivery catheter and then expanded inside the patient by an inflatable balloon or another suitable expansion mechanism. If constructed of a self-expanding material, frame 12 (and thus valve 10) may be crimped into a radially compressed state and restrained in the compressed state by insertion into a delivery catheter sheath or equivalent mechanism. Once inside the body, the valve is advanced from the delivery sheath, allowing it to expand to a functional size.

[0099] Suitable plastically expandable materials that can be used to form the frame 12 include, but are not limited to, stainless steel, nickel-based alloys (e.g., cobalt-chromium or nickel-cobalt-chromium alloys), polymers, or combinations thereof. In certain embodiments, the frame 12 is made of a nickel-cobalt-chromium-molybdenum alloy, such as MP35N® (a trademark of SPS Technologies), which is equivalent to UNS R30035 (covered by ASTM F562-02). MP35N® / UNS R30035 is composed of 35% nickel, 35% cobalt, 20% chromium, and 10% molybdenum by weight. The use of MP35N to form the frame 12 has been found to produce superior structural results compared to stainless steel. In particular, when MP35N is used as the frame material, less material is required to achieve equivalent or better performance in radial and crush force resistance, fatigue resistance, and corrosion resistance. Additionally, because less material is required, the crimp profile of the frame may be reduced, thereby providing a lower profile valve assembly for percutaneous delivery to a treatment location within the body.

[0100] 3 and 4, the frame 12 of the illustrated embodiment is arranged end-to-end and includes a first lower row I of circumferentially extending angled struts 22 at the inflow end of the frame; a second row II of circumferentially extending angled struts 24; a third row III of circumferentially extending angled struts 26; a fourth row IV of circumferentially extending angled struts 28; and a fifth row V of circumferentially extending angled struts 32 at the outflow end 56 of the frame. A plurality of substantially straight, axially extending struts 34 may be used to interconnect the struts 22 of the first row I to the struts 24 of the second row II. The fifth row V of angled struts 32 is connected to the fourth row IV of angled struts 28 by a plurality of axially extending window frame portions 30 (defining the commissure windows 20) and a plurality of axially extending struts 31. Each axial strut 31 and each frame portion 30 extends from a position defined by the convergence of the lower ends of two angled struts 32 to another position defined by the convergence of the upper ends of two angled struts 28.

[0101] Each commissure window frame portion 30 is attached to a respective commissure 58 of the leaflet structure 14. As can be seen, each frame portion 30 is secured at its upper and lower ends to rows of adjacent struts, providing a robust configuration that enhances fatigue resistance under cyclic loading of the valve compared to known cantilever struts for supporting the commissures of a leaflet structure. This configuration allows for a thinner frame wall thickness, thereby reducing the crimp diameter of the valve. In certain embodiments, the thickness T of the frame 12 (FIG. 3), measured between the inner and outer diameters, is about 0.48 mm or less.

[0102] The frame posts and frame portions collectively define a plurality of open cells in the frame. At the inflow end of frame 12, posts 22, 24, and 34 define a lower row of cells that define opening 36. Second, third, and fourth rows of posts 24, 26, and 28 define two middle rows of cells that define opening 38. Fourth and fifth rows of posts 28 and 32, along with frame portion 30 and post 31, define an upper row of cells that defines opening 60. Opening 60 is relatively large and sized to allow a portion of leaflet structure 14 to protrude or expand into and / or through opening 60 when frame 12 is crimped to minimize the crimp profile.

[0103] As shown in FIG. 4 , the lower end of strut 31 connects to two struts 28 at node or junction 44, and the upper end of strut 31 connects to two struts 32 at node or junction 46. Strut 31 may have a thickness less than the thickness of junctions 44, 46. Junctions 44, 46, along with junction 64, each connecting two adjacent struts 32, prevent complete closure of opening 60 when frame 12 is in a crimped state. Therefore, the shape of strut 31 and junctions 44, 46, and 64 helps create sufficient space in crimped opening 60 to allow a portion of the leaflets to protrude outward (i.e., bulge) through the opening. This allows the valve to be crimped to a relatively smaller diameter than if all of the leaflet material were constrained within the crimped frame.

[0104] The frame 12 is configured to prevent or at least minimize valve over-expansion, which may occur at a given balloon pressure, particularly at the outflow end portion of the frame that supports the leaflet structure 14. In one aspect, the frame is configured with relatively large angles 42a, 42b, 42c, 42d, 42e between the struts. The larger the angle, the greater the force required to open (expand) the frame. Thus, the angles between the struts of the frame can be selected to limit the radial expansion of the frame at a given opening pressure (e.g., balloon inflation pressure). In certain embodiments, these angles are at least 110 degrees or greater when the frame is expanded to its functional size, and even more specifically, these angles are at least 120 degrees or greater when the frame is expanded to its functional size. U.S. Patent Application Publication No. 2012 / 0123529 further describes the frame 12, as well as other frame configurations that may be incorporated into prosthetic heart valves.

[0105] 1 and 2, the skirt assembly 15 may include an inner skirt 16 located inside the frame 12 and an outer skirt 18 located outside the frame 12. The outer skirt 18 may include a plurality of circumferentially spaced extensions or protrusions 66 and indentations 68 between adjacent protrusions formed along the outflow edge (top edge in the illustrated embodiment) of the outer skirt. In other embodiments, the outer skirt 18 may have a straight outflow edge without protrusions or indentations (e.g., outer skirt 202 in FIG. 14).

[0106] The inflow (lower) and outflow (upper) edges of the outer skirt 18 may be secured to the frame 12 and / or inner skirt 16 by, for example, heat bonding, gluing, and / or suturing. As shown in the illustrated embodiment, protrusions 66 along the outflow edge of the outer skirt 18 are secured to the frame posts with sutures 70, while recesses 68 between adjacent protrusions may be left unattached to the frame 12 and inner skirt 16. The outer skirt 18 functions as a sealing member for the prosthetic valve 10 by sealing against the tissue of the native annulus, helping to reduce perivalvular leakage through the prosthetic valve 10.

[0107] In some embodiments, as shown in Figures 1 and 2, the outer skirt 18 can be configured to extend radially outward from the frame 12 when the prosthetic valve 10 is in a radially expanded configuration. Alternatively, the outer skirt 18 can be configured to fit snugly against the frame 12 so as to rest against the outer surface of the frame 12 when the prosthetic valve 10 is in a radially expanded configuration (e.g., outer skirt 202 in Figure 14). The outer skirt 18 can be formed from any of a variety of synthetic materials or natural tissues (e.g., pericardial tissue). Suitable synthetic materials include any of a variety of biocompatible fabrics (e.g., PET fabric) or nonwoven films, including any of the materials described below for the reinforcing layer 88 of the inner skirt 16. Further details of the outer skirt 18 are also disclosed in U.S. Patent Application Publication No. 2012 / 0123529.

[0108] As further shown in FIGS. 1 and 2 , the inner skirt 16 in the illustrated embodiment extends from the inlet end 54 of the frame to a location before the fourth row IV of the angled struts 28. In other embodiments, the inner skirt 16 may extend from the inlet end 54 of the frame to a location before the fourth row IV of struts (e.g., the second row II or the third row III of struts), or the inner skirt may extend the entire height of the frame 12 (e.g., from the inlet end 54 to the outlet end 56). In alternative embodiments, the inner skirt 16 may be positioned and / or sized to extend over a different portion of the frame 12 than the configuration shown in FIGS. 1 and 2 . For example, in some embodiments, the inlet end of the inner skirt 16 may be axially spaced from the inlet end 54 of the frame 12.

[0109] Although the inner skirt 16 is typically tubular or cylindrical (forming a complete circle in its cross-sectional profile in a plane perpendicular to the longitudinal axis of the valve), the inner skirt 16 need not extend 360 degrees circumferentially along the inner surface of the frame 12. In other words, the inner skirt 16 may have a cross-sectional profile (in a plane perpendicular to the axis of the valve lumen) that is not a complete circle. The inner skirt 16 may be initially formed as a flat strip and then formed into an annular shape by bonding opposing edges together, for example, by sewing, heat bonding, and / or adhesive bonding. Alternatively, the inner skirt 16 may be directly formed into an annular shape by, for example, constructing the inner layer 16 on a cylindrical mandrel, as described below.

[0110] Referring to Figure 5, inner skirt 16 has a first side 72 that defines the inner skirt's interior surface and a second side 74 that defines the inner skirt's exterior surface. As will be described more fully below, the frame-facing side 74 of inner skirt 16 has one or more windows or openings through which the otherwise encapsulated fabric layer is exposed. Sutures may be threaded through the fabric layer of inner skirt 16 at these windows to secure inner skirt 16 to frame 12. Outer skirt 18 has been omitted from Figure 5 for purposes of illustration.

[0111] When the inner skirt 16 is attached to the frame 12, a first side 72 of the inner skirt 16 faces inward toward the leaflet structure 14 located within the prosthetic valve 10, and a second side 74 of the inner skirt 16 faces outward toward the inner surface of the frame 12. In certain embodiments, the inner skirt 16 may include a reinforcing layer 88 sandwiched between a first covering member 84 and a second covering member 86. In a representative embodiment, the reinforcing layer 88 may be a fabric layer. The first and second covering members 84, 86 may also be referred to as encapsulation layers and form the inner and outer layers, respectively, of the illustrated inner skirt 16. In certain embodiments, the inner surface of the reinforcing layer 88 is completely covered by the first covering member 84 on the first side 72, and the outer surface of the reinforcing layer 88 is partially covered by the second covering member 86 on the second side 74, with the second covering member 86 defining one or more windows or openings 90 (see FIG. 10 ) that expose the reinforcing layer 88 on the second side 74.

[0112] The reinforcing layer 88 may strengthen the inner skirt 16 to resist tearing. It may also function as an anchor layer for suturing the inner skirt 16 to the frame 12 and for supporting the apical portions of the leaflets 40, as described more fully below. Additionally, the reinforcing layer 88, in cooperation with the encapsulation layers 84, 86, may help reduce (or prevent) perivalvular leakage through the prosthetic valve 10 when in the expanded configuration.

[0113] In some embodiments, the reinforcing layer 88 may comprise a woven fabric woven from various types of natural or synthetic fibers (or filaments, or yarns, or strands), including, but not limited to, gauze, PET fibers (e.g., Dacron), polyester fibers, polyamide fibers, ultra-high molecular weight polyethylene (UHMWPE) fibers, etc. In certain embodiments, the reinforcing layer 88 may have a knitted or braided structure rather than a woven structure. Furthermore, the reinforcing layer 88 may be a woven, knitted, or braided structure formed from metal filaments or wires (e.g., nitinol, stainless steel, or titanium filaments or wires), glass filaments or wires, carbon filaments or wires, or ceramic (e.g., aluminum oxide) filaments or wires. Alternatively, the reinforcing layer 88 may comprise filaments, fibers, yarns, or wires made from any of the materials described above, where the filaments, fibers, yarns, or wires are not necessarily interwoven, knitted, or braided together. For example, the reinforcing layer 88 may include layers of parallel filaments, fibers, threads, or wires, or layers of filaments, fibers, threads, or wires stacked one on top of the other. In certain embodiments, the reinforcing layer 88 may include any of a variety of nonwoven fabrics, such as felt. The thickness of the reinforcing layer 88 may vary, but may be less than 6 mils, desirably less than 4 mils, and even more desirably about 2 mils.

[0114] Alternatively, the reinforcing layer 88 may include one or more layers or films formed from any of a variety of semi-crystalline polymeric materials or thermoplastics with aligned or partially aligned (e.g., parallel) molecular chains. Such materials may exhibit anisotropic mechanical properties, such as increased mechanical strength along the length of the molecular chains. Suitable semi-crystalline polymeric materials include, for example, PTFE, PET, polypropylene, polyamide, polyetheretherketone (PEEK), etc., and the layer or film may be disposed between and encapsulated by the encapsulating layers 84, 86 to reinforce the inner skirt 16. Unless otherwise noted, the following description will refer to a fabric layer as an exemplary reinforcing layer for illustrative purposes; however, it should be understood that a non-fabric layer having a sufficiently high tensile strength may also be used as the reinforcing layer.

[0115] The encapsulating layers 84, 86 may be made of any suitable biocompatible material. Desirably, the encapsulating layers 84, 86 comprise a material that is relatively less abrasive than the fabric layers to reduce wear on the leaflets 40. The encapsulating layers 84, 86 may comprise, for example, a membrane or film formed from a nonwoven fabric or non-fibrous material. The biocompatible material used to form the layers 84, 86 is a non-absorbable polymeric material (i.e., a material that does not dissolve once implanted in the body), and the material may be an elastomer. Additionally, either of the encapsulating layers 84, 86 may have a porous microstructure that promotes ingrowth of surrounding tissue to help secure the prosthetic valve 10 in the body lumen.

[0116] Examples of encapsulation layer materials include, but are not limited to, ePTFE, non-expanded porous PTFE, polyester or expanded PTFE yarn, PTFE, ultra-high molecular weight polyethylene (UHMWPE), other polyolefins, PTFE fibers, e.g., ePTFE or UHMWPE fiber-embedded UHMWPE films, polyimides, silicones, polyurethanes, hydrogels, fluoroethylpolypropylene (FEP), polypropylene fluorinated amine (PFA), other related fluorinated polymers, or composite materials such as various combinations of these materials. In certain embodiments, encapsulation layers 84, 86 may be formed from respective tubes made of suitable polymeric materials (e.g., ePTFE or UHMWPE tubing) that can be bonded to one another when subjected to heat treatment. In some embodiments, encapsulation layers 84, 86 may be formed from the same type of material, although different materials may be used to form the encapsulation layers depending on the particular application.

[0117] Microporous ePTFE tubing can be produced by several well-known methods. Expanded PTFE is often produced by mixing particulate dry polytetrafluoroethylene resin with a liquid lubricant to form a viscous slurry. The mixture can be poured into a mold, usually a cylindrical mold, and compressed into a cylindrical billet. The billet is then ram-extruded through an extrusion die into either a tubular or sheet structure, known in the art as an extrudate. The extrudate contains the extruded PTFE-lubricant mixture, known as "wet PTFE." Wet PTFE has a microstructure of coalesced, coherent PTFE resin particles in a highly crystalline state. Following extrusion, the wet PTFE can be heated to a temperature below the flash point of the lubricant to volatilize most of the lubricant from the PTFE extrudate. The resulting PTFE extrudate, free of most of the lubricant, is known in the art as dry PTFE. The dried PTFE can then be expanded uniaxially, biaxially, or radially using appropriate mechanical devices known in the art. Expansion is typically carried out at elevated temperatures, e.g., above room temperature but below PTFE's crystalline melting point of 327°C. Uniaxial, biaxial, or radial expansion of dry PTFE causes the coalesced, coherent PTFE resin to form fibrils emanating from nodes (areas of coalesced PTFE), with the fibrils oriented parallel to the axis of expansion. Once expanded, dry PTFE is called expanded PTFE ("ePTFE") or microporous PTFE.

[0118] UHMWPE is composed of very long chains of polyethylene with a molecular weight in the millions, typically between 2 and 6 million. It has high resistance to aggressive chemicals, very low moisture absorption, and a very low coefficient of friction. It is self-lubricating and has excellent abrasion resistance. UHMWPE is processed using compression molding, ram extrusion, gel spinning, and sintering. UHMWPE is commercially available as powder, sheet or rod, and fiber.

[0119] The encapsulation layers 84, 86 can be formed by several means. For example, in one example, the encapsulation layers 84, 86 can be formed using an electrospinning process, which uses electrical forces to draw electrically charged strands of a polymer solution or melt down to fiber diameters on the order of hundreds of nanometers. In another example, the encapsulation layers 84, 86 can be formed using centrifugal spinning. In centrifugal spinning, a spinning solution is introduced into a rotating spinning head. When the rotational speed reaches a critical value, centrifugal force overcomes the surface tension of the rotating fluid, ejecting a liquid jet from the nozzle tip of the spinning head. The jet then undergoes a drawing process and ultimately deposits on a collector, forming solidified nanofibers. In yet another example, the encapsulation layers 84, 86 can be formed using atmospheric plasma spraying (APS), a specialized variant of the thermal spraying process. APS uses an electric arc to ionize a flowing process gas, allowing the controlled high-temperature gas stream to melt a wide range of powder feedstocks and apply high-quality coatings to target objects. In other embodiments, the encapsulation layers 84, 86 may be formed using any other suitable method, including dip coating, spray coating, melt spinning, etc. For example, one of the encapsulation layers 84, 86 may be formed by dipping the fabric layer 88 into a liquefied polymeric material and then curing the liquefied polymeric material.

[0120] 6-10 illustrate one exemplary process for forming the inner skirt 16. While the use of electrospinning is described below, it is exemplary in nature and not intended to be limiting. It should be understood that other processes for depositing the polymer layer may also be used, such as centrifugal spinning, APS, dip coating, and other processes discussed above.

[0121] First, as shown in FIG. 6 , a first covering member 84 including a first coating material can be deposited circumferentially around the exterior surface of a cylindrical mandrel 100 by electrospinning (or using other techniques). As known in the art, an electrospinning system can include a spinneret used to extrude a polymer solution or melt to form fibers. To deposit the first covering member 84 onto the mandrel 100, the electrospinning system can be configured to rotate the fiber extrusion spinneret in a circular motion around the mandrel 100. Alternatively, the fiber extrusion spinneret can be configured to be stationary while the mandrel 100 is positioned in front of the spinneret and rotates about its longitudinal axis.

[0122] Second, as shown in FIG. 7 , a fabric layer 88 can be disposed over the first covering member 84. The fabric layer 88 can be in the form of a sheet of fabric material that is tightly wrapped around the first covering member 84. For example, as described above, the fabric layer 88 can have a woven structure including warp and weft yarns that extend perpendicular to one another. In alternative embodiments, the fabric layer 88 can also be deposited on the first covering member 84. It should be understood that this construction method is not limited to embodiments in which the reinforcing layer is a woven fabric. This method can be used to form a skirt in which the reinforcing layer can take any of the forms disclosed herein. For example, as described above, the fabric layer 88 can itself be formed by electrospinning and can desirably comprise a nonwoven fabric having a relatively higher tensile strength than layers 84, 86. In another example, the layer 88 can be a preformed braided material that is wrapped around the first covering member 84. In yet another example, layer 88 may be formed by braiding one or more threads or filaments around first covering member 84 to form a braided layer around the first covering member.

[0123] Third, as shown in Figure 8, one or more masks 92 may be placed on the fabric layer 88 in selected regions 94 of the fabric. Fourth, as shown in Figure 9, a second covering member 86 including a second coating material may be deposited on the masked fabric layer 88 by electrospinning (or using other techniques). Then, as shown in Figure 10, the mask 92 is removed after deposition of the second covering member 86. Thus, one or more windows 90 corresponding to the selected regions 94 are created such that the windows 90 expose the underlying fabric layer 88.

[0124] 8 and 9 , the mask 92 may temporarily cover selected regions 94 of the fabric layer 88 to prevent those selected regions 94 from being deposited with the second coating material of the second covering member 86. Alternatively, the selected regions 94 may be functionally masked without the need to apply a physical mask 94. For example, the associated movement and operation (e.g., activation and / or deactivation) of the fiber extrusion spinneret relative to the mandrel 100 may be programmed so that the second coating material of the second covering member 86 may be deposited only on portions of the fabric layer 88 outside of the selected regions 94.

[0125] In the embodiment shown in FIGS. 8 and 9 , three annular bands of mask 92 are shown, each corresponding to three selected regions 94 along the periphery of fabric layer 88. As a result, three annular windows 90 are created after removal of mask 92, as shown in FIG. 10 . In other embodiments, any one of masks 92 may have a non-annular shape, such that the corresponding selected regions 94 and resulting windows 90 do not completely surround fabric layer 88. For example, any one of masks 92 may have a customized shape at a customized location to create a customized window 90. Furthermore, while three windows 90 are shown in the illustrated embodiment, the inner skirt may be formed with a fewer or greater number of windows, which may be positioned anywhere along the skirt. For example, in some embodiments, the inner skirt may be formed with one or more circumferentially extending rows of windows, each row consisting of multiple circumferentially spaced windows. In other embodiments, one or more windows may be formed along the inlet and / or outlet edges of the inner skirt.

[0126] Although not shown, it should be understood that a securing mechanism may be provided at each step described above to temporarily secure the position of each layer. As a non-limiting example, a layer of PTFE tape may be wrapped around one or both ends of the second covering member 86 to help secure the position of the second covering member 86 to the underlying layers of the assembly and the mandrel 100 during subsequent processing.

[0127] In an exemplary embodiment, the fabric layer 88 has a plurality of openings that allow the first covering member 84 and the second covering member 86 to fuse to one another through the openings. In one example, the openings in the fabric layer 88 may be created by weaving, braiding, or knitting fibers or yarns to form the fabric layer. In another example, the fabric layer 88 may have a nonwoven porous structure with openings. In another example, such as when a nonwoven fabric (e.g., felt) is used to form the fabric layer, the openings in the fabric layer 88 may be formed by cutting (e.g., laser cutting) openings in the fabric layer.

[0128] In one exemplary embodiment, fusion between the first and second covering members 84, 86 through the openings in the fabric layer 88 can occur simultaneously during the process of depositing the second covering member 86 onto the masked fabric layer 88. When the second coating material extruded from the spinneret is deposited onto the fabric layer 88 to form the second covering member 86, some of the second coating material can penetrate those openings in the fabric layer 88 and fuse with the fibers of the coating of the first covering member 84.

[0129] In other embodiments, fusion between the first and second covering members 84, 86 can occur after depositing the second covering member 86 on the masked fabric layer 88. For example, the assembly shown in FIG. 10 can undergo an encapsulation process, whereby the assembly is exposed to heat and / or pressure to bond the first and second covering members 84, 86 to one another through openings in the fabric layer 88. Additionally, the fabric layer 88 can have a shorter axial length than the first and second covering members 84, 86, facilitating bonding at the respective ends of the first and second covering members 84, 86 to encapsulate the fabric layer 88 therebetween. Similar encapsulation processes are described in U.S. Patent Application Publication Nos. 2014 / 0209238 and 2016 / 0317305, both of which are incorporated herein by reference.

[0130] In an exemplary embodiment, ePTFE may be used as the first coating material for depositing the first covering member 84 and / or the second coating material for depositing the second covering member 86. Alternatively, other materials may be used, such as UHMWPE, polyurethane composites, or any other non-absorbable polymeric materials described above. The inner skirt 16 may desirably have a laminated structure in which the fabric layer 88 is sandwiched between two fused layers, i.e., the first covering member 84 and the second covering member 86. In some embodiments, the same material may be used to deposit the first and second covering members 84, 86. Layer-to-layer fusion or bonding may merge the first and second covering members 84, 86 together, effectively creating a single structure in which the fabric layer 88 is encapsulated (i.e., there is no physical boundary between the layers). The density of the first covering member 84 may be the same or different from the density of the second covering member 86. In other embodiments, the first coating material used to deposit the first coating member 84 may be different from the second coating material used to deposit the second coating member 86.

[0131] After the first and second covering members 84, 86 are securely fused together to encapsulate the fabric layer 88, the inner skirt 16 may be removed from the mandrel 100. One or both ends of the inner skirt 16 may be trimmed to achieve the desired height of the inner skirt. The inner skirt 16 may then be attached to the frame 12.

[0132] 6-10 and the above description illustrate the process of forming the annular-shaped inner skirt 16, it should be understood that the same process can be used to form the outer skirt 18. Furthermore, as described above, the inner skirt 16 can be initially formed as a flat strip and then formed into an annular shape by bonding two opposing edges thereof together. To form a flat strip, the first and second covering members 84, 86 and the fabric layer 88 can be constructed on a flat substrate instead of the cylindrical mandrel 100 as described above.

[0133] While the process described above uses masking to create the windows 90 on the second covering member 86 of the inner skirt 16, it should be understood that other methods can be used to create the windows 90. For example, the second covering member 86 can first be deposited over the entire surface of the fabric layer 88. Selected regions 94 on the second covering member 86 can then be located and removed, for example, by laser cutting, chemical attack, or other means. As a result, windows 90 are created in the selected regions 94 on the second covering member 86, exposing the underlying fabric layer 88 therein. In another example, the second covering member 86 can be pre-fabricated to lack the second coating material in the selected regions 94. The pre-fabricated second covering member 86 can then be wrapped around the fabric layer 88. As a result, the fabric layer 88 can be exposed through the windows 90 created in the selected regions 94. The assembly (first covering member 84, fabric layer 88, and second covering member 86) may then undergo a heat and / or pressure-based encapsulation process, as described above, to bond the first and second covering members 84, 86 to one another.

[0134] The inner skirt 16 may be sewn to the frame 12 at the locations of the windows 90. For example, the inner skirt 16 may be positioned inside the frame 12. The locations of the windows 90 may generally be positioned to correspond to the first, third, and fourth rows of struts 22, 26, and 28, respectively, although other configurations may be used. As described further below in connection with FIGS. 11-13 , the inner skirt 16 may also be secured to the first, third, and fourth rows of struts using sutures that extend around the struts and through the fabric layer 88 at the locations of the windows 90. Because the windows in the illustrated embodiment extend continuously around the entire circumference of the inner skirt, a continuous, circumferentially extending whip stitch may be formed along the fabric layer 88 of each row of struts and each window 90.

[0135] As discussed above, the windows 90 may be created at selected locations and have any of a variety of shapes, and the inner skirt may be sewn to the frame at different locations. For example, as discussed above, the inner skirt may be formed with a row of windows at circumferentially spaced portions, thereby allowing for the placement of individual sutures or stitches that do not extend continuously along the entire row of struts, such as in selected portions of the inner skirt that are subject to tension or stress.

[0136] 11-13 illustrate an exemplary method of stitching the inner skirt 16 to the frame 12. FIG. 11 shows a cross-sectional view of a portion of the inner skirt 16 having a first side 72 and a second side 74. As described above, the inner skirt 16 has an encapsulated fabric layer 88 sandwiched between a first covering member 84 on the first side 72 and a second covering member 86 on the second side 74. FIG. 11 also shows a window 90 on the second covering member 86 of the inner skirt 16, exposing the underlying fabric layer 88. If the same material is used to form the encapsulating layers 84, 86, the interlayer boundary (shown by the dashed line) may not be present and may be fused or bonded to form a single, integrated structure that encapsulates the fabric. In the illustrated embodiment, the fabric layer 88 is shown to have a woven structure including woven filaments, fibers, or yarns 96. The woven filaments 96 desirably have sufficient strength to serve as anchors for retaining sutures 98, as described below.

[0137] 12 schematically illustrates a method for threading a thread 98 between the fabric layer 88 and the first covering member 84 through the window 90. In the illustrated embodiment, the suture 98 is attached to a needle 102. The tip 108 of the needle 102 is desirably blunted. By applying light pressure to the needle tip 108 while sliding the needle 102 through the window 90 from the second side 74, the first covering member 84 may be slightly pushed away from the fabric layer 88, thereby creating a space between the first covering member 84 and the fabric layer 88 through which the needle 102 may be inserted. As illustrated, the needle 102 and attached suture 98 may be slid into the fabric layer 88 from the first end 104 of the window 90, passed behind one or more filaments 96 (e.g., 96a and 96b) exposed by the window 90, and then slid out of the fabric layer 88 at the second end 106 of the window 90. In this manner, the suture 98 does not extend through the entire thickness of the inner skirt 16. In some embodiments, the first covering member 84 is not separated from the fabric layer 88 by the insertion of the needle 102 (as shown in FIG. 12 ), in which case the needle 102 and attached suture 98 may pass partially through the thickness of the first covering member 84, but not through the entire thickness of the inner skirt.

[0138] FIG. 13 schematically illustrates suturing the fabric layer 88 of the inner skirt 16 to adjacent struts 22 of the frame 12. Desirably, the first side 72 of the inner skirt 16 faces inward toward the leaflet structure 14 located within the prosthetic valve 10, and the second side 74 of the inner skirt 16 faces outward toward the frame 12. By threading a needle 102 and attached suture 98 through the window 90 between the fabric layer 88 and the first covering member 84, the woven filaments 96 between the first and second ends 104, 106 (e.g., 96a and 96b) of the window 80 can collectively function as anchors to hold the suture 98. The suture 98 can then be wrapped around adjacent struts 22 to secure the woven filaments (e.g., 96a and 96b) to the adjacent struts 22. Thus, the inner skirt 16 can be securely attached to the frame 12. FIG. 13 shows the struts 22 for illustrative purposes. It should be understood that the inner skirt 16 may be sewn to the other struts (eg, 26, 28, 32) of the frame in a similar manner.

[0139] As mentioned above, the fabric layer 88 may also have a nonwoven structure without separate woven threads 96. In such cases, the sutures 98 may be attached to needles with sharp tips. The needles may be used to pierce and thread the sutures 98 through the fabric layer 88. In this manner, the portion of the fabric layer 88 between the first and second ends 104, 106 of the window 90 may serve as an anchor to hold the sutures 98, thereby securing that portion of the fabric to the adjacent posts. Thus, the inner skirt 16 may be securely attached to the frame 12.

[0140] Because the sutures 98 are disposed between the first covering member 84 and the fabric layer 88, they are not exposed on the first side 72 of the inner skirt 16. In other words, the sutures 98 are covered by the first covering member 84. The inner surface of the fabric layer is also covered by the first covering member. Therefore, wear of the leaflets 40 due to repeated contact between the leaflets 40 and the inner skirt 16 and between the leaflets 40 and the sutures 98 during the operating cycle of the prosthetic valve 10 can be avoided. Desirably, the inner skirt 16 is sewn to the frame 12 only at one or more windows 90 on the second covering member 86, thereby avoiding contact between the moving portions of the leaflets 40 and the sutures 98. Furthermore, the first covering member 84 desirably covers the entire inner surface of the fabric layer, or at least the portion of the fabric layer that will contact the moving portions of the leaflets during the operating cycle of the prosthetic valve. In some embodiments, the suture 98 may pass through the entire thickness of the inner skirt, such as at a location on the inner skirt that would not contact the moving portions of the leaflets.

[0141] As described above, the leaflets 40 may be secured to each other at their adjacent sides to form commissures 58. Each commissure 58 may be secured to a corresponding commissure window 20 in the frame 12, as described in U.S. Patent Application Publication No. 2012 / 0123529. The inflow or cusp edge 52 of the leaflet 40 may be sutured to the inner skirt 16 along a suture line that tracks the curvature of the scalloped inflow edge of the leaflet structure. The fabric layer 88 may provide the necessary strength to hold the suture. Any suitable suture, such as Ethibond suture, may be used to secure the leaflet 40 to the fabric layer 88 of the inner skirt.

[0142] In some embodiments, the inflow edge 52 of the leaflet 40 is secured to the inner skirt 16 before the inner skirt 16 is attached to the frame. After the leaflet 40 is secured to the inner skirt 16, the inner skirt is secured to the frame and the leaflet commissures 58 are attached to the frame as described above. In other embodiments, the inner skirt 16 can be attached to the frame without the leaflet, and then the leaflet's inflow edge 52 is secured to the inner skirt.

[0143] In certain embodiments, the inflow edge 52 of the leaflet 40 may be secured to the inner skirt via a thin PET reinforcement strip (not shown), as disclosed in U.S. Pat. No. 7,993,394, which is incorporated herein by reference. As described in U.S. Pat. No. 7,993,394, the reinforcement strip may be sewn to the inflow edge of the leaflet. The reinforcement strip and the lower edge of the leaflet may then be sewn to the inner skirt 16. The reinforcement strip is desirably secured to the inner surface of the leaflet 40 such that the inflow edge 52 of the leaflet is sandwiched between the reinforcement strip and the inner skirt when the leaflet and reinforcement strip are secured to the inner skirt. The reinforcement strip allows for secure suturing and protects the pericardial tissue of the leaflet structure from laceration.

[0144] As mentioned above, the outer skirt 18 may be constructed in a manner similar to the inner skirt 16. That is, the outer skirt 18 may also have a reinforcing layer (e.g., a fabric layer 88) sandwiched between the encapsulation layers 84, 86. Similarly, a window 90 may be fabricated on one of the encapsulation layers 84, 86. Because the outer skirt 18 is attached to the outside of the frame 12, the outer layer 18 is desirably positioned so that the frame 12 faces the side of the outer skirt 18 having the window 90. In such an arrangement, the outer skirt 18 may be attached to the frame 12 by stitching the encapsulated fabric layer 88 to the frame 12 through the window 90 facing the frame.

[0145] In yet another embodiment, the outer skirt 18 may have the fabric layer 88 coated with only one of the encapsulation layers 84, 86. During attachment of the outer skirt 18 to the frame 12, the outer skirt 18 is positioned so that the uncoated side of the fabric layer 88 faces inward toward the frame 12, so that the outer skirt 18 may be attached to the frame 12 by stitching the exposed fabric layer 88 to the frame 12.

[0146] Alternatively, the outer skirt 18 may include only the fabric layer 88, without either of the encapsulation layers 84, 86. Thus, the outer skirt 18 may be sewn directly to the frame 12. Because the sutures on the outer skirt 18 are not subjected to repeated contact by the movable leaflets 40, leaflet abrasion due to the sutures on the outer skirt 18 may be less of a concern than the sutures on the inner skirt 16. By eliminating one or both of the encapsulation layers 84, 86, the outer layer 18 may be constructed thinner, thus reducing the overall profile of the valve 10 when crimped into a radially compressed state.

[0147] Figure 14 shows a prosthetic valve 200 according to another embodiment. The prosthetic valve 200 may have the same structure and components as the prosthetic valve 10 of Figures 1 and 2, except that the prosthetic valve 200 includes a different outer skirt. Components common to Figures 1 and 2 and Figure 14 are labeled with the same reference numbers and will not be described further.

[0148] The prosthetic valve 200 includes an outer skirt 202 of similar structure to the inner skirt 16. Accordingly, the outer skirt 202 includes an inner encapsulation layer 204, an outer encapsulation layer 206, and a reinforcing layer 208 disposed between the encapsulation layers 204, 206. The outer skirt is attached to the outside of the frame 12. The skirt 202 may be formed and attached to the frame 12 using any of the techniques described above in connection with the skirt 16. FIG. 15 shows a cross-sectional view of the frame 12 and outer skirt 202, with the other components of the prosthetic valve removed for illustrative purposes. The outer skirt 202 may be configured to fit snugly against the outer surface of the frame 12 when the prosthetic valve 200 is in a radially expanded configuration, as shown in FIGS. 14 and 15 .

[0149] When the prosthetic valve 200 is radially compressed or crimped into a radially compressed state (e.g., on a balloon of a delivery device) and delivered into a patient, the frame 12 is elongated along the frame's longitudinal axis L. When the prosthetic valve is radially expanded from the radially compressed state to the radially expanded state, the frame 12 shortens axially forward along axis L. If the outer skirt fits relatively tightly or snugly around the frame 12, it is desirable that the outer skirt exhibit sufficient axial elongation or stretchability so as not to impede the elongation of the frame 12 during crimping of the prosthetic valve.

[0150] Toward such end, in certain embodiments, the reinforcing layer 208 includes threads, filaments, fibers, or wires that are non-perpendicular to the upper and lower edges 214, 216, respectively, of the skirt 202. Stated differently, the threads, filaments, fibers, or wires extend at an angle greater than 0 degrees and less than 90 degrees relative to the longitudinal axis L of the frame 12 (the threads, filaments, fibers, or wires are non-parallel and non-perpendicular to the longitudinal axis L of the frame).

[0151] In certain embodiments, the reinforcing layer 208 comprises a textile with interwoven yarns, such as a woven, braided, or knitted structure. In certain embodiments, the reinforcing layer 208 comprises a fabric, such as a plain weave fabric, having a first set of yarns 210 woven together with a second set of yarns 212, wherein the yarns 210, 212 are not perpendicular to the top edge 214 and bottom edge 216 of the skirt, respectively. Stated another way, the yarns 210, 212 extend at an angle greater than 0 degrees and less than 90 degrees relative to the longitudinal axis L of the frame 12.

[0152] In some examples, the threads 210, 212 extend at an angle ranging from 20 degrees to 70 degrees relative to the upper and lower edges 214, 216, more desirably ranging from 30 degrees to 60 degrees relative to the upper and lower edges 210, 216, and even more desirably ranging from 40 degrees to 50 degrees relative to the upper and lower edges 214, 216. In certain embodiments, the threads 210, 212 extend at 45 degrees relative to the upper and lower edges 214, 216 and the longitudinal axis L of the prosthetic valve.

[0153] In some embodiments, threads 210, 212 are parallel to the frame struts to which the outer skirt is connected when the prosthetic valve is in an expanded state. In certain embodiments, skirt 202 is sutured to one or more of angled struts 22, 24, 26, and 28 (see FIG. 4 ). The frame struts to which the outer skirt is connected are also referred to as “skirt support struts.” Typically, although not necessarily, the skirt support struts are oriented at a 45-degree angle relative to the longitudinal axis L. However, in other embodiments, the skirt support struts and threads 210, 212 may be at an angle greater than or less than 45 degrees relative to the longitudinal axis L, depending on the particular frame configuration.

[0154] The fabric layer 208 may be formed by weaving yarns at a selected angle (e.g., 45 degrees) relative to the top and bottom edges of the fabric. Alternatively, the fabric layer 208 may be cut diagonally from a vertically woven fabric (where the yarns extend perpendicular to the edges of the material) so that the fibers extend at a selected angle (e.g., 45 degrees) relative to the top and bottom edges at which the fabric is cut. The yarns 210, 212 may comprise multifilament yarns (yarns containing multiple fibers or filaments) or monofilament yarns (yarns containing a single fiber or filament).

[0155] In some embodiments, the frame 12 may be partially crimped during assembly of the prosthetic valve so that the skirt support struts are parallel to the threads 210, 212 in the partially crimped state. The skirt 202 may then be attached to the frame in the partially crimped state, such as by any of the techniques described herein.

[0156] Due to the orientation of the yarns relative to the upper and lower edges, the fabric layer can undergo greater stretch in the axial direction (i.e., from the upper edge 214 to the lower edge 216, parallel to axis L). Thus, when the metal frame 12 is crimped, the skirt 202 can stretch axially with the frame, thus providing a more uniform and predictable crimp profile. Each cell of the metal frame in the illustrated embodiment includes at least four angled struts (e.g., struts 22, 24, 26) that rotate toward the axial direction (i.e., the angled struts are more aligned along the length of the frame). The angled struts in each cell act as a mechanism for rotating the yarns 210, 212 of the fabric layer 208 in the same direction as the struts, allowing the skirt 202 to stretch along the length of the struts. This allows for greater stretch in the skirt, avoiding undesirable deformation of the struts when the prosthetic valve is crimped. As mentioned above, the encapsulation layers 204, 206 may be made of any of the various elastomers described above in connection with layers 84 and 86, such as silicone or polyurethane, that can stretch axially when the prosthetic valve is crimped and the frame is stretched.

[0157] The movement of the threads 210, 212 during crimping is shown in Figures 16A and 16B. Figure 16A shows portions of the two interlaced threads 210, 212 when the outer skirt 202 is in a relaxed state, which corresponds to the radially expanded state of the prosthetic valve 200. Figure 16B shows the threads 210, 212 when the outer skirt 202 is in an axially stretched or elongated state, which corresponds to the radially compressed state of the prosthetic valve after crimping. As shown, the threads 210, 212 move from a 45-degree angular orientation relative to the longitudinal axis L toward an orientation in which the threads are closer to being parallel to the longitudinal axis L.

[0158] Additionally, the spacing between the woven (or braided or knitted) yarns can be increased to facilitate axial stretching of the skirt 202. For example, in certain embodiments, the fabric layer 208 can have a weave density of less than 150 ppi (picks per inch), more desirably less than 100 ppi, more desirably less than 70 ppi, and even more desirably 50 ppi or less. In certain embodiments, the fabric layer 208 can have a weave density of about 30 to about 50 ppi, compared to known fabric skirts having weave densities of about 150 to 160 ppi. This structure can allow the skirt 202 to stretch or elongate axially to at least 40% of its initial length D when the prosthetic valve is radially compressed (initial length D is the distance between the upper edge 214 and the lower edge 216 of the skirt when the prosthetic valve is in a radially expanded state). At such low weave densities, textiles (e.g., woven, braided, or knitted structures) with interwoven yarns tend to be unstable and may unravel. Advantageously, the encapsulation layers 204, 206 encapsulate the yarns and act as a support mechanism to prevent unraveling of the relatively loose weave. Additionally, during the assembly process described above in connection with FIGS. 6-10 , the first encapsulation layer (layer 84 in FIGS. 6-10 ) can be adhered to the fiber reinforced layer (layer 88), which can help stabilize the fibers and prevent fraying until the second encapsulation layer (layer 86) is formed or placed over the fiber reinforced layer. Additionally, as described above, the fiber reinforced layer in some embodiments can be braided around the first encapsulation layer supported on the mandrel 100, which helps further stabilize the braid.

[0159] In particular embodiments, the yarns 210, 212 can have about 10 to about 50 filaments per yarn, with 20 filaments per yarn being a particular example. The filaments of the yarns 210, 212 can have a thickness ranging from about 8 microns to about 16 microns, with 10 microns being a particular example. The filaments of the yarns 210, 212 can be made of PTE or UHMWPE, although the filaments can be made of any of the materials described above in connection with the reinforcement layer 88.

[0160] In certain embodiments, the yarns 210, 212 can be textured to increase the axial elasticity of the skirt. For example, the yarns can be bulked, e.g., twisted or coiled, heat-set, untwisted, or unrolled, so that the yarns retain a deformed shape (e.g., twisted or coiled) in a relaxed or unstretched configuration. When the prosthetic valve is radially compressed and the skirt 202 is stretched axially, the yarns 210, 212 can straighten from their deformed state (e.g., twisted or coiled), increasing the elasticity and elongation of the skirt. Fabrics including textured yarns are further disclosed in U.S. Patent Application Publication No. 2018 / 0206982, which is incorporated herein by reference. The yarns 210, 212 can be embedded within elastomeric encapsulation layers 204, 206, so that the encapsulation layers can stretch axially to accommodate the straightening of the yarns 210, 212. The use of such textured threads 210, 212 allows the skirt 202 to stretch axially more than 40% of its initial length D when the prosthetic valve is radially compressed.

[0161] In some embodiments, the reinforcing layer 208 may be a fabric, as described above, with the addition of one or more leno yarns woven into the fabric to increase the stability of the fabric. Any of a variety of leno weave patterns may be used to weave the leno yarns into the fabric layer 208. Details regarding fabric skirts including leno weaves are disclosed in U.S. Patent Application Publication No. 2019 / 0192296, filed July 24, 2019, and U.S. Patent Application No. 16 / 521,226, both of which are incorporated herein by reference.

[0162] In alternative embodiments, reinforcing layer 208 may have any structure and be made from any of the materials described above in connection with reinforcing layer 88. Reinforcing layer 208 may also be or include any of the fibers disclosed in U.S. Patent Application Publication No. 2019 / 0192296 and U.S. Patent Application No. 16 / 521,226. For example, reinforcing layer 208 may be a braided or knitted layer, which may be formed from yarns, filaments, or wires made from any of the above-mentioned materials, including synthetic materials, metals, glass, carbon, or ceramics. Alternatively, reinforcing layer 208 may include filaments, fibers, yarns, or wires made from any of the above-mentioned materials, where the filaments, fibers, yarns, or wires are not necessarily interwoven, braided, or knitted together. For example, reinforcing layer 208 may include layers of parallel filaments, fibers, yarns, or wires, or layers of filaments, fibers, yarns, or wires stacked one on top of the other.

[0163] In those embodiments in which the reinforcement layer 208 comprises a braid or knit layer, the threads, fibers, or wires may be oriented at a non-perpendicular angle (e.g., 45 degrees) relative to the upper and lower edges 214, 216 of the skirt 202 to facilitate elongation of the skirt during crimping of the prosthetic valve. Similarly, if the reinforcement layer is formed from threads, fibers, or wires that are not interwoven, braided, or woven together, the threads, fibers, or wires may be oriented at a non-perpendicular angle (e.g., 45 degrees) relative to the upper and lower edges 214, 216 of the skirt 202 to facilitate elongation of the skirt during crimping of the prosthetic valve.

[0164] FIG. 17 shows an example cross-section of a braided reinforcement layer 300 that may be used in the skirt 202. In FIG. 17, the x-axis represents the circumferential direction of the skirt 202, and the y-axis represents the axial direction of the skirt 202. The braided layer 300 is composed of first and second sets of threads 302, 304 braided together, such as in a biaxial braid. FIG. 17 shows the braided layer 300 when the prosthetic valve is radially expanded. This may mean that the braided layer is in a relaxed state, meaning that the braided layer is not stretched or elongated in any direction (or at least not axially stretched or elongated). As shown, the threads 302, 304 may be oriented at a 45-degree angle relative to the longitudinal axis L, forming a 90-degree braid angle 306. Thus, in some embodiments, the threads 302, 304 may extend parallel to the struts of the frame 12 when the frame is in a radially expanded state.

[0165] Braided layer 300 may have a braid density similar to that described above for fabric layer 208 to facilitate skirt elongation. Accordingly, braided layer 300 may have a braid density of less than 150 ppi, more desirably less than 100 ppi, more desirably less than 70 ppi, and even more desirably 50 ppi or less. In particular examples, braided layer 300 has a braid density of about 30 to about 50 ppi.

[0166] To help stabilize the braid, layer 300 may include a third set of axially extending threads 308 braided together with threads 302, 304 to form a triaxial braid. Threads 308 may be made of an elastomer (e.g., polyurethane (PU), such as thermoplastic polyurethane (TPU)) that can stretch axially when the prosthetic valve is radially compressed. Alternatively, or in addition to forming threads 308 from an elastomer, threads 308 may be textured, as described above, to increase the elasticity of the skirt in the axial direction. Threads 302, 304 may be made of the same material as threads 308 or a different material.

[0167] Additionally, the reinforcing layers 208, 300 may be hybrid textiles (e.g., woven, braided, or knitted structures) incorporating yarns or filaments of different materials with different material properties. For example, one or more yarns of the textile may be relatively less elastic or inelastic than one or more other yarns of the textile. In one embodiment, for example, one or more relatively less elastic yarns may be made of PET, and one or more relatively more elastic yarns may be made of PU, TPU, or other elastomer. The less elastic yarns may be selectively positioned (according to a predefined pattern) within the textile to strengthen the textile, while the more elastic yarns may be selectively positioned (according to a predefined pattern) to promote elasticity in a given direction (e.g., axially). For example, in the embodiment of FIG. 17, yarns 302, 304 may be made of PET, and yarn 308 may be made of PU or TPU.

[0168] It should be understood that the inner skirt 16 can have any of the configurations described above for the outer skirt 202. For example, in some embodiments, the inner skirt 16 of the prosthetic valve 10, 200 can similarly have threads, fibers, or wires oriented at a non-perpendicular angle (e.g., 45 degrees) relative to the upper and lower edges of the skirt 16 to facilitate elongation of the skirt during crimping of the prosthetic valve.

[0169] In some embodiments, the prosthetic valve 200 may have an inner skirt 16 that comprises a conventional woven fabric without an encapsulation layer. In other embodiments, the prosthetic valve may lack an inner skirt 16.

[0170] [General Considerations] It should be understood that the disclosed embodiments are adapted to deliver and implant a prosthesis into any of the heart's native valve annulus (e.g., pulmonary, mitral, and tricuspid) and may be used with any of a variety of delivery approaches (e.g., retrograde, antegrade, transseptal, transventricular, transatrial, etc.).

[0171] For purposes of this description, certain aspects, advantages, and novel features of the disclosed embodiments are described herein. The disclosed methods, devices, and systems should not be construed as limiting in any way. Instead, the present disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments, both alone and in various combinations and subcombinations with one another. The methods, devices, and systems are not limited to any particular aspect or feature or combination thereof, and the disclosed embodiments do not require that any one or more particular advantages be present or problems be solved. Techniques from any example may be combined with techniques described in any one or more other examples. Given the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are merely preferred examples and should not be construed as limiting the scope of the disclosed technology.

[0172] Although some operations of the disclosed embodiments are described in a particular sequential order for convenience, it should be understood that the method of description includes rearrangement unless a particular order is required by specific terminology set forth below. For example, operations described in a sequence may in some cases be rearranged or performed simultaneously. Moreover, for simplicity, the accompanying figures may not show the various ways in which the disclosed methods can be used in combination with other methods. Furthermore, the description may use terms such as "provide" or "achieve" to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations corresponding to these terms may vary depending on the particular implementation and are readily discernible by those skilled in the art.

[0173] As used in this application and the claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Furthermore, the term "comprises" means "comprising." Furthermore, the terms "coupled" and "connected" generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or linked and do not exclude the presence of intermediate elements between coupled or related items in the absence of specific terms to the contrary.

[0174] Directions and other relative references (e.g., inside, outside, top, bottom, etc.) may be used to facilitate explanation of the figures and principles herein, but are not intended to be limiting. For example, specific terms such as "inside," "outside," "up," "down," "inside," "outside," etc. may be used. Such terms are used, where applicable, to add some clarity to the description when dealing with relative relationships, particularly with respect to the illustrated embodiments. However, such terms are not intended to imply absolute relationships, positions, and / or directions. For example, with respect to an object, a "top" part can become a "bottom" part simply by flipping the object over. Nevertheless, it is still the same part, and the object remains the same. As used herein, "and / or" means "and" or "or," as well as "and" and "or."

[0175] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are merely preferred examples of the invention and should not be considered as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope of those claims. [Explanation of symbols]

[0176] 10,200 artificial valves 12 Stents, frames 14 Valve structure 15 Skirt Assembly 16 Inner skirt 18 outer skirt, outer layer 20 Commissural window 30 Frame part 22, 24, 26, 28, 31, 32, 34 posts 38, 60 opening 40 Leaflets 42 angle 44, 46, 64 nodes, junctions 48 Inlet end 50 Outlet end 54 Inlet end 56 Outlet end 58 commissure 66 Protrusion 68 Depression 70, 98 sutures 72 First Aspect 74 Second Aspect 84 First covering member, encapsulation layer 86 Second covering member, encapsulation layer 88 Reinforcement layer, fabric layer 90 Windows 92 Mask 94 areas 96 Filaments, yarns 100 mandrels 102 needles 104 first end 106 Second end 108 Tip 200 Artificial Valves 202 Outer Skirt 204 inner encapsulation layer 206 outer encapsulation layer 208 Reinforcement layer, fabric layer 210, 212, 302, 304 Thread 214 Upper Edge 216 Lower Edge 300 braided reinforcement layer 306 Braid angle

Claims

1. an annular frame radially expandable from a radially compressed state to a radially expanded state, the annular frame having an inlet end, an outlet end, and a longitudinal axis extending from the inlet end to the outlet end; a plurality of leaflets arranged to regulate blood flow from the inflow end to the outflow end of the frame; a skirt assembly comprising a laminate having a fibrous layer sandwiched between a first encapsulation layer and a second encapsulation layer; 1. An implantable prosthetic valve comprising:

1. An implantable prosthetic valve, wherein the first encapsulation layer and the second encapsulation layer are made of an elastomer, the fabric layer includes a first set of threads and a second set of threads interwoven with the first set of threads, and the first set of threads and the second set of threads are non-perpendicular and non-parallel to the longitudinal axis.

2. 2. The prosthetic valve of claim 1, wherein the fiber layer has a weave density of less than 150 ppi.

3. 3. The prosthetic valve of claim 2, wherein the fiber layer has a weave density of 50 ppi or less.

4. 4. The prosthetic valve of claim 3, wherein the fibrous layer has a weave density of about 30 to about 50 ppi.

5. The prosthetic valve of any one of claims 1 to 4, wherein the skirt assembly includes an outer skirt attached to an outer surface of the frame.

6. The prosthetic valve of any one of claims 1 to 5, wherein the skirt assembly includes an inner skirt attached to an inner surface of the frame.

7. The artificial valve according to any one of claims 1 to 6, wherein the fiber layer is a braided layer.

8. The artificial valve according to any one of claims 1 to 7, characterized in that the textile layer is a woven layer.

9. The artificial valve according to any one of claims 1 to 6, wherein the fiber layer is a knit layer.

10. 10. The prosthetic valve according to claim 1, wherein the threads of the first set of threads and the second set of threads are oriented at an angle in the range of 20 to 70 degrees relative to the longitudinal axis of the frame.

11. 11. The prosthetic valve of claim 10, wherein the threads of the first set of threads and the second set of threads are oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

12. 12. The prosthetic valve of claim 11, wherein the threads of the first set of threads and the second set of threads are oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

13. 13. The prosthetic valve of claim 12, wherein the threads of the first set of threads and the second set of threads are oriented at a 45 degree angle relative to the longitudinal axis of the frame.

14. 14. The prosthetic valve of any one of claims 1 to 13, wherein the threads of the first thread set and the second thread set have about 10 to about 50 filaments per thread.

15. 15. The prosthetic valve of claim 14, wherein the threads of the first thread set and the second thread set have about 20 filaments per thread.

16. 16. The prosthetic valve of claim 14 or 15, wherein the filaments of the yarn have a thickness ranging from about 8 microns to about 16 microns.

17. 17. The prosthetic valve of claim 16, wherein the filaments of the yarn have a thickness of about 10 microns.

18. 18. The prosthetic valve of claim 1, wherein at least some of the threads in the first set of threads and the second set of threads are textured such that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

19. The artificial valve according to any one of claims 1 to 18, characterized in that the textile layer comprises leno yarn.

20. 20. The prosthetic valve of claim 1, wherein the threads of the first thread set and the second thread set comprise a first type of thread and a second type of thread, and the first type of thread is less elastic or inelastic than the second type of thread.

21. 21. The prosthetic valve of any one of claims 1 to 20, wherein the textile layer includes a third set of axially extending threads that are braided together with threads of the first set of threads and the second set of threads to form a triaxial braid.

22. 22. The prosthetic valve of claim 21, wherein the third set of threads is made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

23. 22. The prosthetic valve of claim 21, wherein the third set of threads are textured such that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

24. 24. The prosthetic valve of claim 1, wherein when the prosthetic valve is in a radially compressed state, the skirt assembly is axially elongated to at least 40% of its initial length when the prosthetic valve is in a radially expanded state.

25. an annular frame radially expandable from a radially compressed state to a radially expanded state, the annular frame having an inlet end, an outlet end, and a longitudinal axis extending from the inlet end to the outlet end; a plurality of leaflets arranged to regulate blood flow from the inflow end to the outflow end of the frame; an outer skirt attached to an outer surface of the frame, the outer skirt comprising a laminate having a fibrous layer sandwiched between a first encapsulating layer and a second encapsulating layer, the first encapsulating layer and the second encapsulating layer being made of an elastomer, the fibrous layer including a first set of yarns and a second set of yarns interwoven with the first set of yarns; 1. An implantable prosthetic valve comprising:

1. An implantable prosthetic valve, wherein the outer skirt has a first axial length when the prosthetic valve is in a radially expanded state and a second axial length when the prosthetic valve is in a radially compressed state, the second axial length being 40% greater than the first axial length.

26. 26. The prosthetic valve of claim 25, wherein the outer skirt is configured to fit snugly against the frame such that the outer skirt abuts an outer surface of the frame when the prosthetic valve is in a radially expanded state.

27. 27. The prosthetic valve of claim 25 or 26, wherein the first set of threads and the second set of threads are each parallel to corresponding struts of the frame to which the outer skirt is connected when the prosthetic valve is in a radially expanded state.

28. 28. The prosthetic valve according to any one of claims 25 to 27, wherein the first set of threads and the second set of threads are non-perpendicular and non-parallel to a longitudinal axis of the frame extending from the inflow end to the outflow end.

29. 30. The prosthetic valve of claim 28, wherein the threads of the first thread set and the second thread set are oriented at an angle in the range of 20 to 70 degrees relative to the longitudinal axis of the frame.

30. 30. The prosthetic valve of claim 29, wherein the threads of the first set of threads and the second set of threads are oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

31. 31. The prosthetic valve of claim 30, wherein the threads of the first set of threads and the second set of threads are oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

32. 32. The prosthetic valve of claim 31, wherein the threads of the first set of threads and the second set of threads are oriented at a 45 degree angle relative to the longitudinal axis of the frame.

33. The artificial valve according to any one of claims 25 to 32, characterized in that the fiber layer has a weave density of less than 150 ppi.

34. 34. The prosthetic valve of claim 33, wherein the fiber layer has a weave density of 50 ppi or less.

35. 35. The prosthetic valve of claim 34, wherein the fabric layer has a weave density of about 30 to about 50 ppi.

36. 36. The prosthetic valve of any one of claims 25 to 35, wherein at least some of the threads in the first set of threads and the second set of threads are textured to retain a twisted or coiled state when the prosthetic valve is in a radially expanded state and to straighten out in an untwisted or uncoiled state when the prosthetic valve is in a radially compressed state.

37. 37. The prosthetic valve of any one of claims 25 to 36, wherein the threads of the first thread set and the second thread set comprise a first type of thread and a second type of thread, and the first type of thread is less elastic or inelastic than the second type of thread.

38. 38. The prosthetic valve of any one of claims 25 to 37, wherein the textile layer includes a third set of axially extending threads that are braided together with threads of the first set of threads and the second set of threads to form a triaxial braid.

39. 39. The prosthetic valve of claim 38, wherein the third set of threads is made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

40. 39. The prosthetic valve of claim 38, wherein the third set of threads are textured such that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

41. 1. A method of assembling a prosthetic valve, comprising: mounting the skirt assembly to an annular frame, the annular frame being radially expandable from a radially compressed state to a radially expanded state; attaching a plurality of leaflets to the annular frame, the leaflets configured to regulate blood flow from an inflow end to an outflow end of the frame; 1. A method of assembling a prosthetic valve, comprising: the skirt assembly comprises a laminate having a fibrous layer sandwiched between a first encapsulating layer and a second encapsulating layer, the first encapsulating layer and the second encapsulating layer being made of an elastomer, the fibrous layer comprising a first set of yarns and a second set of yarns interwoven with the first set of yarns; 1. A method of assembling a prosthetic valve, wherein an outer skirt has a first axial length when the prosthetic valve is in a radially expanded state and a second axial length when the prosthetic valve is in a radially compressed state, the second axial length being at least 40% of the first axial length.

42. 42. The method of claim 41, wherein the skirt assembly includes an inner skirt, and the act of attaching the plurality of leaflets to an annular frame includes attaching the inner skirt to an inner surface of the frame and further sewing the plurality of leaflets to the inner skirt.

43. 43. The method of claim 41 or 42, wherein the skirt assembly includes an outer skirt, and the act of attaching the skirt assembly to the annular frame includes placing the outer skirt around an outer surface of the frame and sewing the outer skirt to selected posts of the frame.

44. 44. The method of any one of claims 41 to 43, further comprising forming a laminate by forming a first encapsulation layer by electrospinning, disposing the fibrous layer on the first encapsulation layer, and forming a second encapsulation layer on the fibrous layer by electrospinning.

45. A method according to any one of claims 41 to 43, further comprising forming a laminate by immersing the fibrous layer in a liquefied polymeric material, and then curing the liquefied polymeric material.

46. 46. ​​The method of any one of claims 41 to 45, further comprising providing the fiber layer such that the first set of yarns and the second set of yarns are non-perpendicular and non-parallel to a longitudinal axis of the frame extending from an inflow end to an outflow end.

47. 47. The method of claim 46, wherein the step of providing a fibrous layer includes weaving the first set of yarns and the second set of yarns at a selected angle relative to a top and bottom edge of a fabric.

48. 47. The method of claim 46, wherein the step of providing a fibrous layer includes cutting diagonally from a fabric having yarns extending perpendicular to the edges of the fabric.

49. 49. The method of any one of claims 46 to 48, wherein the yarns of the first yarn set and the second yarn set are oriented at an angle in the range of 20 to 70 degrees relative to the longitudinal axis of the frame.

50. 50. The method of claim 49, wherein the threads of the first thread set and the second thread set are oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

51. 51. The method of claim 50, wherein the threads of the first thread set and the second thread set are oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

52. 52. The method of claim 51, wherein the threads of the first thread set and the second thread set are oriented at a 45 degree angle relative to the longitudinal axis of the frame.

53. 53. The method according to any one of claims 41 to 52, characterized in that the fibrous layer has a weave density of less than 150 ppi.

54. 54. The method of claim 53, wherein the fibrous layer has a weave density of 50 ppi or less.

55. 55. The method of claim 54, wherein the fibrous layer has a weave density of about 30 to about 50 ppi.

56. 56. The method of any one of claims 41 to 55, wherein the textile layer comprises a third axially extending yarn set that is braided with yarns of the first yarn set and the second yarn set to form a triaxial braid.

57. 57. The method of claim 56, wherein the third set of threads is made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

58. 57. The method of claim 56, wherein the third set of threads are textured such that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

59. 1. A method of assembling a prosthetic valve, comprising: mounting a plurality of leaflets on a radially expandable annular frame from a radially compressed state to a radially expanded state, the annular frame having an inflow end, an outflow end, and a longitudinal axis extending from the inflow end to the outflow end, the plurality of leaflets being configured to regulate blood flow from the inflow end to the outflow end of the annular frame; attaching a skirt assembly to the annular frame, the skirt assembly including a laminate having a fabric layer sandwiched between a first encapsulation layer and a second encapsulation layer, the first encapsulation layer and the second encapsulation layer being made of an elastomer, the fabric layer including a first set of threads and a second set of threads interwoven with the first set of threads, the first set of threads and the second set of threads being non-perpendicular and non-parallel to the longitudinal axis; A method comprising:

60. 60. The method of claim 59, wherein the fibrous layer has a weave density of less than 150 ppi.

61. 61. The method of claim 60, wherein the fibrous layer has a weave density of 50 ppi or less.

62. 62. The method of claim 61, wherein the fibrous layer has a weave density of about 30 to about 50 ppi.

63. A method according to any one of claims 59 to 62, wherein the skirt assembly includes an outer skirt attached to an outer surface of the frame.

64. A method according to any one of claims 59 to 63, wherein the skirt assembly includes an inner skirt attached to an inner surface of the frame.

65. 65. The method according to any one of claims 59 to 64, characterized in that the textile layer is a braided layer.

66. A method according to any one of claims 59 to 64, characterized in that the textile layer is a woven layer.

67. 65. The method according to any one of claims 59 to 64, characterized in that the textile layer is a knitted layer.

68. 68. The method of any one of claims 59 to 67, wherein the yarns of the first yarn set and the second yarn set are oriented at an angle in the range of 20 to 70 degrees relative to a longitudinal axis of the frame.

69. 69. The method of claim 68, wherein the threads of the first thread set and the second thread set are oriented at an angle in the range of 30 to 60 degrees relative to the longitudinal axis of the frame.

70. 70. The method of claim 69, wherein the threads of the first thread set and the second thread set are oriented at an angle in the range of 40 to 50 degrees relative to the longitudinal axis of the frame.

71. 71. The method of claim 70, wherein the threads of the first thread set and the second thread set are oriented at a 45 degree angle relative to the longitudinal axis of the frame.

72. 72. The method of any one of claims 59-71, wherein the yarns of the first yarn set and the second yarn set have from about 10 to about 50 filaments per yarn.

73. 73. The method of claim 72, wherein the yarns of the first yarn set and the second yarn set have about 20 filaments per yarn.

74. 74. The method of claim 72 or 73, wherein the filaments of the yarn have a thickness in the range of about 8 microns to about 16 microns.

75. 75. The method of claim 74, wherein the filaments of the yarn have a thickness of about 10 microns.

76. 76. The method of any one of claims 59-75, wherein at least some of the threads in the first set of threads and the second set of threads are textured to retain a twisted or coiled state when the prosthetic valve is in a radially expanded state and to straighten out in an untwisted or uncoiled state when the prosthetic valve is in a radially compressed state.

77. 77. The method of any one of claims 59 to 76, characterized in that the fibrous layer comprises leno yarns.

78. 78. The method of any one of claims 59 to 77, wherein yarns of the first yarn set and the second yarn set comprise a first type of yarn and a second type of yarn, and the first type of yarn is less elastic or inelastic than the second type of yarn.

79. 79. The method of any one of claims 59 to 78, wherein the textile layer comprises a third axially extending yarn set that is braided with yarns of the first yarn set and the second yarn set to form a triaxial braid.

80. 80. The method of claim 79, wherein the third set of threads is made of an elastomer configured to stretch axially when the prosthetic valve is radially compressed from a radially expanded state to a radially compressed state.

81. 80. The method of claim 79, wherein the third set of threads are textured such that they are held in a twisted or coiled state when the prosthetic valve is in a radially expanded state and are untwisted or uncoiled and straight when the prosthetic valve is in a radially compressed state.

82. 82. The method of any one of claims 59 to 81, wherein when the prosthetic valve is in the radially compressed state, the skirt assembly is axially elongated to at least 40% of its initial length when the prosthetic valve is in the radially expanded state.

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