Heart valve with floating outer skirt for improved sealing - Patents.com

Abstract

The implantable medical device is adapted to be implanted at an implantation site, such as a native heart valve annulus. The implantable medical device includes an expandable frame adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment, one or more valve leaflets fixed relative to the expandable frame, an inner skirt surrounding a portion of the expandable frame, and an outer skirt surrounding a portion of the expandable frame, the outer skirt attached to the expandable frame via one or more sutures that axially fix the outer skirt to the expandable frame but allow the outer skirt to move radially relative to the expandable frame. The outer skirt may move radially outward in response to fluid pressure, thereby improving the fluid seal against the native heart valve annulus.

Description

[Technical Field]

[0001] The present disclosure relates generally to medical devices, and more particularly to replacement heart valves. [Background technology]

[0002] A wide variety of intracorporeal medical devices have been developed for medical applications, such as intravascular applications. Some of these devices include guidewires, catheters, and the like. These devices can be manufactured by any one of a variety of different manufacturing methods and used according to any one of a variety of methods. Each of the known medical devices and methods has certain advantages and disadvantages. There is a continuing need to provide alternative medical devices and alternative methods for manufacturing and using medical devices. Summary of the Invention

[0003] The present disclosure provides design, material, manufacturing, and use alternatives for medical devices. One example can be found in an implantable medical device adapted to be implanted at an implantation site. The implantable medical device includes an expandable frame adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment, one or more valve leaflets fixed relative to the expandable frame, an inner skirt surrounding a portion of the expandable frame, and an outer skirt surrounding a portion of the expandable frame, the outer skirt attached to the expandable frame via one or more sutures that axially secure the outer skirt to the expandable frame but allow the outer skirt to move radially relative to the expandable frame.

[0004] Alternatively, or in addition, the expandable frame may include an upper crown portion, a lower crown portion, a joint post extending proximally from the upper crown portion, and a stabilizing arch extending proximally from the joint post.

[0005] Alternatively, or in addition, each of the one or more sutures may be secured to one of the joint posts. Alternatively, or in addition, each of the one or more sutures may extend beyond the corresponding joint post and may loop around the base of the stabilizing arch above the corresponding joint post.

[0006] Alternatively, or in addition, each of the sutures may be enclosed within a leaflet that is secured to each of the coaptation posts. Alternatively, or in addition, the distal edge of the outer skirt may be sewn to the inner skirt and the proximal edge of the outer skirt may overlap at least a portion of the upper crown portion.

[0007] Alternatively, or in addition, each of the one or more sutures may be adapted to allow the proximal edge of the outer skirt to bulge outward in response to fluid pressure on the outer skirt.

[0008] Alternatively, or in addition, both ends of each of the one or more sutures may be attached to the outer skirt at a single location. Alternatively, or in addition, for each of the one or more sutures, a first end of the suture may be attached to the outer skirt at a first location and a second end of the suture may be attached to the outer skirt at a second location circumferentially spaced from the first location.

[0009] Another example can be found in a replacement heart valve adapted to be implanted within a native heart valve annulus. The replacement heart valve includes an expandable frame adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment, the frame including an upper crown portion, a lower crown portion, a coaptation post extending proximally from the upper crown portion, and a stabilizing arch extending proximally from the coaptation post. The replacement heart valve includes one or more leaflets secured to the expandable frame, an inner skirt surrounding a portion of the expandable frame, and an outer skirt surrounding a portion of the expandable frame, the outer skirt adapted to bulge outward in response to fluid pressure on the outer skirt, thereby sealing against the native heart valve annulus.

[0010] Alternatively, or in addition, the outer skirt may be attached to the expandable frame via one or more sutures that secure the outer skirt axially relative to the expandable frame but allow the outer skirt to move radially relative to the expandable frame.

[0011] Alternatively, or in addition, the distal edge of the outer skirt may be sewn to the inner skirt and the proximal edge of the outer skirt may overlap at least a portion of the upper crown portion.

[0012] Alternatively, or in addition, the inner skirt may cover the lower crown portion. Alternatively, or in addition, both ends of each of the one or more sutures may be attached to the outer skirt at a single location.

[0013] Alternatively, or in addition, for each of the one or more sutures, a first end of the suture may be attached to the outer skirt at a first location and a second end of the suture may be attached to the outer skirt at a second location circumferentially spaced from the first location.

[0014] Alternatively, or in addition, the replacement heart valve may include a replacement aortic valve. Another example can be found in a replacement aortic valve adapted to be implanted within the native aortic valve annulus. The replacement heart valve is adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment and includes an expandable frame including an upper crown portion, a lower crown portion, a coaptation post extending proximally from the upper crown portion, and a stabilizing arch extending proximally from the coaptation post. The replacement aortic valve includes one or more leaflets fixed relative to the expandable frame and a sealing skirt surrounding a portion of the expandable frame, the sealing skirt adapted to bulge outward in response to aortic pressure on the sealing skirt when the one or more leaflets are closed, thereby sealing the sealing skirt against the aortic valve annulus.

[0015] Alternatively, or in addition, the sealing skirt may be attached to the expandable frame via one or more sutures that secure the sealing skirt axially relative to the expandable frame but allow the sealing skirt to move radially relative to the expandable frame.

[0016] Alternatively, or in addition, both ends of each of the one or more sutures may be attached to the sealing skirt at a single location. Alternatively, or in addition, for each of the one or more sutures, a first end of the suture may be attached to the sealing skirt at a first location and a second end of the suture may be attached to the sealing skirt at a second location circumferentially spaced from the first location.

[0017] The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The following figures and detailed description more particularly exemplify these embodiments.

[0018] The present disclosure may be more fully understood from the following detailed description considered in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0019] [Figure 1]1A-1C are diagrams of an expandable frame of an exemplary replacement aortic valve. [Figure 2] 2 is a diagram of an exemplary replacement aortic valve utilizing the expandable frame of the exemplary replacement aortic valve of FIG. 1. [Figure 3] 2 is a diagram of an exemplary replacement aortic valve utilizing the expandable frame of the exemplary replacement aortic valve of FIG. 1. [Figure 4] 10 is a graph showing experimental results. DETAILED DESCRIPTION OF THE INVENTION

[0020] While the present disclosure is susceptible to various modifications and alternative forms, specifics of which have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0021] For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. All numerical values ​​are assumed to be modified herein by the term "about," whether explicitly stated or not. The term "about" generally refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the term "about" may include numbers that are rounded to the nearest significant figure.

[0022] The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is used generally in its sense including "and / or" unless the content clearly dictates otherwise.

[0023] It should be noted that references herein to "embodiments," "some embodiments," "other embodiments," etc., indicate that the described embodiments may include one or more particular features, structures, and / or characteristics. However, such descriptions do not necessarily imply that all embodiments include the particular feature, structure, and / or characteristic. In addition, when a particular feature, structure, and / or characteristic is described in connection with one embodiment, it should be understood that such feature, structure, and / or characteristic may also be used in connection with other embodiments, whether or not explicitly described, unless expressly stated otherwise.

[0024] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.

[0025] FIG. 1 is a side view of an exemplary replacement heart valve expandable frame 10. The replacement heart valve expandable frame 10 may be used as a starting point for constructing, for example, a replacement aortic valve, a replacement mitral valve, a replacement pulmonary valve, or a replacement tricuspid valve. In some cases, the resulting replacement heart valve may include biological tissue, such as porcine or bovine pericardium, and / or natural heart valve leaflets, such as natural porcine heart valve leaflets, secured to the replacement heart valve expandable frame 10. In some cases, the natural heart valve leaflets may be attached to a portion of the natural heart wall tissue. The biological material may be secured using, for example, glutaraldehyde.

[0026] The replacement heart valve expandable frame 10 may be compressible into a radially compressed or collapsed configuration for delivery using a delivery catheter and expandable into an expanded configuration (as shown) during implantation. In some cases, the replacement heart valve expandable frame 10 may include a lower tubular or crown portion 16, an upper crown portion 18, a plurality of upstanding joint posts 20, and a plurality of stabilizing arches 22. In use, the lower portion 16 of the replacement heart valve expandable frame 10 may be adapted to be deployed after other regions of the replacement heart valve expandable frame 10. For example, the arches 22, supports 20, and upper crown 18 may be deployed at least partially before the lower portion 16 (in that order, or in the reverse order, or in a different order). Once at least the upper crown 18 is at least partially deployed, the replacement heart valve expandable frame 10 may be biased and / or displaced in the direction of arrow 24 to seat the upper crown 18 against the native valve leaflets at the implantation site. In this example, the final deployment of the lower portion 16 secures the replacement heart valve expandable frame 10 in its final position.

[0027] The lower portion 16, and optionally a portion of the upper crown 18, may be formed by the lattice structure of the stent. The lattice structure may define cells or openings, for example, generally diamond-shaped openings. In some cases, the native leaflets may generally overlap portion 26 of the expandable frame 10 of the replacement heart valve. The native annulus may overlap portion 28 of the expandable frame.

[0028] The replacement heart valve expandable frame 10 may optionally be self-expanding, compressible to a compressed configuration for loading into a delivery catheter for delivery to the implantation site. During use, by removing the restraining effect of the sheath that holds the replacement heart valve expandable frame 10 in the compressed configuration, the replacement heart valve expandable frame 10 self-expands to or toward an operating configuration. The self-expanding stent may be, for example, a shape-memory material, such as a shape-memory metal alloy, for example, Nitinol. Alternatively, the replacement heart valve expandable frame 10 may be configured to be expanded by applying a shortening force from the delivery catheter, such as by using a dilation balloon, and / or by applying an expanding force from the delivery catheter. These are merely examples.

[0029] FIG. 2 is a side view of an exemplary replacement heart valve 30 that can be constructed using the replacement heart valve expandable frame 10 as a starting point. The exemplary replacement heart valve 30 includes several leaflets 32. While a total of two leaflets 32 are visible in this illustration, in some cases, the replacement heart valve 30 may include any number of leaflets 32, and in some cases, may include a total of three leaflets 32 equidistantly spaced around the replacement heart valve expandable frame 10. In some cases, for example, the leaflets 32 may be formed from biological tissue, such as porcine or bovine pericardium, and / or natural heart valve leaflets, such as natural porcine heart valve leaflets. In some cases, the natural heart valve leaflets may be attached to portions of natural heart wall tissue. The biological material may be secured in place using, for example, glutaraldehyde. The leaflets 32 may be secured in place relative to the replacement heart valve expandable frame 10 via adhesive or by being suturing them into place.

[0030] The replacement heart valve 30 includes an inner skirt 34 that surrounds the lower crown portion 16 and, optionally, at least a portion of the upper crown portion 18 of the replacement heart valve expandable frame 10. The inner skirt 34 may be formed from biological tissue, such as porcine or bovine pericardium, and / or natural heart valve leaflets, such as natural porcine heart valve leaflets. In some cases, the natural heart valve leaflets may be attached to portions of the natural heart wall tissue. The biological material may be fixed, for example, with glutaraldehyde. The inner skirt 34 may be fixed in place relative to the replacement heart valve expandable frame 10 by any of a number of methods, including adhesives or being sutured in place.

[0031] The replacement heart valve 30 includes an outer skirt 36 that overlaps the inner skirt 34. The outer skirt 36 can be considered a sealing skirt, as described below. The outer skirt 36 can be considered to have a proximal region 38 and a distal region 40. In some cases, the distal region 40 of the outer skirt 36 may be sutured in place, such as via sutures 42 and / or sutures 44. The sutures 42 and / or sutures 44 may secure the distal region 40 of the outer skirt 36 to the inner skirt 34. In some cases, the sutures 42 and / or sutures 44 may secure the distal region 40 of the outer skirt 36 to the expandable frame 10 of the replacement heart valve.

[0032] In some cases, the proximal region 38 of the outer skirt 36 may be attached to the expandable frame 10 of the replacement heart valve by one or more sutures 46. The one or more sutures 46 may be formed from any suitable thread or wire. As an example, the one or more sutures 46 may be PTFE (polytetrafluoroethylene) coated braided polyester (such as PET or polyethylene terephthalate). While a single suture 46 is shown, it is understood that there may be several sutures 46 distributed around the replacement heart valve 30. As an example, there may be a suture 46 positioned to interact with each of the coaptation posts 20. Each suture 46 may be considered to have a first free end 46a and a second free end 46b. The suture 46 extends from the first free end 46a to a point 46c where the suture 46 loops over a portion of the stabilization arch 22 and returns to the second free end 46b. Although the sutures 46 are shown as looping over a portion of the stabilization arch 22, in some cases, each suture 46 may instead be secured to the joint post 20 or to a frame strut extending proximally toward the joint post 20.

[0033] As shown in FIG. 2 , the first free end 46 a and the second free end 46 b are both secured to the proximal region 38 of the outer skirt 36 at a common point 48. The replacement heart valve 30 can be considered a first version of a parachute seal due to how the sutures 46 are secured to the proximal region 38 of the outer skirt 36. Because the proximal region 38 of the outer skirt 36 is secured via the sutures 46 rather than by tying a knot, the proximal region 38 of the outer skirt 36 is free to expand or distend radially outward as a result of fluid pressure against the interior of the outer skirt 36 when the leaflets 32 are in the closed position. As the outer skirt 36 fills with blood and expands radially, the outer skirt 36 helps to seal against leakage between the outer skirt 36 and the native valve annulus.

[0034] FIG. 3 is a side view of an exemplary replacement heart valve 50 that can be constructed using the replacement heart valve expandable frame 10 as a starting point. The exemplary replacement heart valve 50 includes several leaflets 32. While a total of two leaflets 32 are visible in this illustration, in some cases, the replacement heart valve 50 may include any number of leaflets 32, and in some cases, may include a total of three leaflets 32 equidistantly spaced around the replacement heart valve expandable frame 10. In some cases, for example, the leaflets 32 may be formed from biological tissue, such as porcine or bovine pericardium, and / or natural heart valve leaflets, such as natural porcine heart valve leaflets. In some cases, the natural heart valve leaflets may be attached to portions of the natural heart wall tissue. The biological material may be secured in place using, for example, glutaraldehyde. The leaflets 32 may be secured in place relative to the replacement heart valve expandable frame 10 by any of a number of methods, including adhesives or being sutured in place.

[0035] The replacement heart valve 50 includes an inner skirt 34 that surrounds the lower crown portion 16 and, optionally, at least a portion of the upper crown portion 18 of the replacement heart valve expandable frame 10. The inner skirt 34 may be formed from biological tissue, such as porcine or bovine pericardium, and / or natural heart valve leaflets, such as natural porcine heart valve leaflets. In some cases, the natural heart valve leaflets may be attached to portions of the natural heart wall tissue. The biological material may be fixed, for example, with glutaraldehyde. The inner skirt 34 may be secured in place relative to the replacement heart valve expandable frame 10 via adhesive or by being suturing in place.

[0036] The replacement heart valve 50 includes an outer skirt 36 that overlaps the inner skirt 34. The outer skirt 36 can be considered a sealing skirt, as described below. The outer skirt 36 can be considered to have a proximal region 38 and a distal region 40. In some cases, the distal region 40 of the outer skirt 36 may be sutured in place, such as via sutures 42 and / or sutures 44. The sutures 42 and / or sutures 44 may secure the distal region 40 of the outer skirt 36 to the inner skirt 34. In some cases, the sutures 42 and / or sutures 44 may secure the distal region 40 of the outer skirt 36 to the expandable frame 10 of the replacement heart valve.

[0037] In some cases, the proximal region 38 of the outer skirt 36 may be attached to the expandable frame 10 of the replacement heart valve by one or more sutures 46. While a single suture 46 is shown, it is understood that there may be several sutures 46 distributed around the replacement heart valve 50. As an example, there may be a suture 46 positioned to interact with each of the commissure posts 20. Each suture 46 may be considered to have a first free end 46a and a second free end 46b. The suture 46 extends from the first free end 46a to a point 46c where the suture 46 loops over a portion of the stabilization arch 22 and returns to the second free end 46b. While the sutures 46 are shown as looping over a portion of the stabilization arch 22, in some cases, each suture 46 may instead be secured to the commissure post 20 or to a frame strut extending proximally toward the commissure post 20.

[0038] As shown in FIG. 3 , the first free end 46 a is secured to the proximal region 38 of the outer skirt 36 at a first location 52, and the second free end 46 b is secured to the proximal region 38 of the outer skirt 36 at a second location 54 circumferentially spaced from the first location 52. The replacement heart valve 50 can be considered a second version of a parachute seal due to how the sutures 46 are secured to the proximal region 38 of the outer skirt 36. Because the proximal region 38 of the outer skirt 36 is secured via the sutures 46 rather than by tying a knot, the proximal region 38 of the outer skirt 36 is free to expand or distend radially outward as a result of fluid pressure against the interior of the outer skirt 36 when the valve leaflets 32 are in the closed position. As the outer skirt 36 fills with blood and expands radially, the outer skirt 36 helps to seal against leakage between the outer skirt 36 and the native valve annulus.

[0039] 4 is a graph providing experimental evidence demonstrating improved sealing performance by securing the proximal region 38 of the outer skirt 36 to the expandable frame 10 of a replacement heart valve using sutures 46 that allow radial movement of at least the proximal region 38 of the outer skirt 36. In the graph, the data point for "standard installation" refers to a replacement heart valve, such as replacement aortic valve 30 or replacement aortic valve 50, in which the proximal region 38 of the outer skirt 36 is secured in place by a series of knots spaced circumferentially around the proximal region 38 of the outer skirt 36. It will be understood that the outer skirt 36 is not radially expandable in areas adjacent to each of the knots. In some cases, there may be a total of six knots.

[0040] The data point labeled "Parachute Configuration 1" corresponds to a valve, such as replacement aortic valve 30, in which the free ends 46a and 46b of each suture 46 are anchored at common point 48. The data point labeled "Parachute Configuration 2" corresponds to a valve, such as replacement aortic valve 50, in which the free ends 46a and 46b of each suture 46 are anchored at spaced apart points 52 and 54. As can be seen, the data point labeled "Parachute Configuration 1" represents an 18.3 percent reduction in total aortic regurgitation rate relative to the "Standard Installation" data point. The data point labeled "Parachute Configuration 2" is even better, representing a 35.3 percent reduction in total aortic regurgitation rate relative to the "Standard Installation" data point.

[0041] Materials that can be used for the devices described herein can include materials commonly associated with medical devices. The devices described herein, or components thereof, can be made from metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, ceramics, combinations thereof, or other suitable materials. Some examples of suitable metals and metal alloys include stainless steels such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloys such as linear elastic and / or superelastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625, such as INCONEL® 625; UNS: N06022, such as HASTELLOY® C-22; HASTELLOY® C-22). 276, other HASTELLOY® alloys, etc. UNS:N10276), nickel-copper alloys (e.g., UNS:N04400, such as MONEL® 400, NICKELVAC™ 400, NICORROS® 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N™), nickel-molybdenum alloys (e.g., HASTELLOY® ALLOY B2®, UNS:N10665), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, etc.; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY®, PHYNOX®); platinum-strengthened stainless steel; titanium; combinations thereof; the like; or any other suitable material.

[0042] As suggested herein, within the family of commercially available nickel-titanium or nitinol alloys, there is a category referred to as "linear elastic" or "non-superelastic," which may be chemically similar to conventional shape memory and superelastic species but may exhibit distinct and useful mechanical properties. Linear elastic and / or non-superelastic nitinol may be distinguished from superelastic nitinol in that linear elastic and / or non-superelastic nitinol does not exhibit a substantial "superelastic plateau" or "flag region" in its stress / strain curve as does superelastic nitinol. Instead, in linear elastic and / or non-superelastic nitinol, as recoverable strain increases, stress continues to increase in a substantially linear, or somewhat but not necessarily completely linear, relationship, or at least a relationship that is more linear than the superelastic plateau and / or flag region that may be seen in superelastic nitinol, until plastic deformation begins. Thus, for purposes of this disclosure, linear elastic and / or non-superelastic nitinol may also be referred to as "substantially" linear elastic and / or non-superelastic nitinol.

[0043] Additionally, in some cases, linear elastic and / or non-superelastic nitinol can be distinguished from superelastic nitinol in that linear elastic and / or non-superelastic nitinol can tolerate strains of up to about 2-5% while remaining substantially elastic (e.g., before plastic deformation), while superelastic nitinol can tolerate strains of up to about 8% before plastic deformation. Both of these materials can be distinguished from other linear elastic materials, such as stainless steel (which can also be distinguished based on its composition), which can only tolerate strains of about 0.2-0.44 percent before plastic deformation.

[0044] In some embodiments, linear elastic and / or non-superelastic nickel-titanium alloys are alloys that do not exhibit a martensite / austenite phase change detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) analysis over a wide temperature range. For example, in some embodiments, linear elastic and / or non-superelastic nickel-titanium alloys may not exhibit a martensite / austenite phase change detectable by DSC and DMTA analysis over a range of about -60°C to about 120°C. Thus, the mechanical bending properties of such materials may be generally inert to the effects of temperature over this very wide temperature range. In some embodiments, the mechanical bending properties of linear elastic and / or non-superelastic nickel-titanium alloys at ambient or room temperature are substantially the same as those at body temperature, e.g., in that they do not exhibit a superelastic plateau and / or flag region. In other words, over a wide temperature range, linear elastic and / or non-superelastic nickel-titanium alloys maintain their linear elastic and / or non-superelastic properties and / or characteristics.

[0045] In some embodiments, the linear elastic and / or non-superelastic nickel-titanium alloy may range from about 50 to about 60 weight percent nickel, with the remainder essentially titanium. In some embodiments, the composition ranges from about 54 to about 57 weight percent nickel. One example of a suitable nickel-titanium alloy is FHP-NT alloy, commercially available from Furukawa Techno Material Co., Ltd., Kanagawa Prefecture, Japan. Some examples of nickel-titanium alloys are disclosed in U.S. Patent Nos. 5,238,004 and 6,508,803, which are incorporated herein by reference. Other suitable materials include ULTANIUM™ (available from Neo-Metrics) and GUM METAL® (available from Toyota). In some other embodiments, superelastic alloys, such as superelastic nitinol, may be used to achieve desired properties.

[0046] In at least some embodiments, the devices disclosed herein, or components thereof, may also be doped with, made from, or otherwise include a radiopaque material. A radiopaque material is understood to be a material capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. Some examples of radiopaque materials include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials loaded with radiopaque fillers, and the like. Additionally, other radiopaque marker bands and / or coils may also be incorporated into the design of the guidewire 10 to achieve the same results.

[0047] In some embodiments, a degree of magnetic resonance imaging (MRI) compatibility is imparted to the devices described herein, or components thereof. For example, the devices described herein, or components thereof, may be made from materials that do not substantially distort images or produce substantial artifacts (e.g., gaps in the images). For example, certain ferromagnetic materials may not be suitable because they may produce artifacts in MRI images. The devices described herein, or components thereof, may also be made from materials that can be imaged by MRI machines. Some materials that exhibit these properties include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY®, PHYNOX®), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N™), nitinol, and the like, as well as others.

[0048] A sheath or cover (not shown) may be disposed over some or all of the devices described herein to define a generally smooth exterior surface. However, in other embodiments, such a sheath or cover may be absent. The sheath may be made of a polymer or other suitable material. Some examples of suitable polymers include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN® available from DuPont), polyether block esters, polyurethanes (e.g., Polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyetheresters (e.g., ARNITEL® available from DSM Engineering Plastics), ether or ester-based copolymers (e.g., butylene / poly(alkylene ether) phthalates and / or other polyester elastomers such as HYTREL® available from DuPont), polyamides (e.g., DURETHAN® or Elf® available from Bayer), and the like. CRISTAMID™ available from Atochem), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA, e.g., available under the trade name PEBAX®), ethylene vinyl acetate copolymer (EVA), silicone, polyethylene (PE), MARLEX® high density polyethylene, MARLEX® low density polyethylene, linear low density polyethylene (e.g., REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon 12 (EMS AmericanExamples of suitable materials include ethylene glycol ether (EGF), propylene glycol ether (PPGA), propylene glycol ether (PG ...

[0049] In some embodiments, the outer surface of the devices described herein may be sandblasted, bead-blasted, sodium bicarbonate-blasted, electropolished, or the like. In these and some other embodiments, a coating, such as a lubricious, hydrophilic, protective, or other type of coating, may be applied. Alternatively, the sheath may include a lubricious, hydrophilic, protective, or other type of coating. Hydrophobic coatings, such as fluoropolymers, provide dry lubricity, which improves guidewire handling and device exchange. Lubricious coatings improve steerability and lesion crossing capabilities. Suitable lubricious polymers are well known in the art and may include hydrophilic polymers, such as silicones, for example, high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxide, polyvinylpyrrolidone, polyvinyl alcohol, hydroxyalkyl cellulose, algin, saccharides, caprolactone, and the like, as well as mixtures and combinations thereof. Hydrophilic polymers may be blended among themselves or with formulated amounts of water-insoluble compounds (including some polymers) to obtain a coating with suitable lubricity, binding, and solubility properties. Some other examples of such coatings, as well as the materials and methods used to make such coatings, can be found in U.S. Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference.

[0050] Portions of the devices described herein may be formed, for example, by coating, extrusion, coextrusion, interrupted layer coextrusion (ILC), or end-to-end fusing of several sections. A layer may have uniform stiffness or a gradual decrease in stiffness from its proximal to distal end. The gradual decrease in stiffness may be continuous, as with ILC, or stepwise, as with fusing separate extruded tubular segments together. The outer layer may be impregnated with a radiopaque filler material to facilitate radiographic imaging. Those skilled in the art will recognize that these materials may vary widely without departing from the scope of the present disclosure.

[0051] It will be understood that this disclosure is, in many respects, merely illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps, without exceeding the scope of the disclosure. This may include, to the extent appropriate, the use of any of the features of one illustrative embodiment used in other embodiments. The scope of the invention will, of course, be defined in the language in which the appended claims are expressed.

Claims

1. 1. An implantable medical device adapted to be implanted at an implantation site, comprising: an expandable frame adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment; one or more leaflets fixed relative to the expandable frame; an inner skirt surrounding a portion of the expandable frame; an outer skirt surrounding a portion of the expandable frame, the outer skirt attached to the expandable frame via one or more sutures that axially secure the outer skirt relative to the expandable frame but allow the outer skirt to move radially relative to the expandable frame; An implantable medical device comprising:

2. The expandable frame comprises: An upper crown portion; A lower crown portion; a joint post extending proximally from the upper crown portion; a stabilizing arch extending proximally from the joint post; 10. The implantable medical device of claim 1, comprising:

3. The implantable medical device of claim 2 , wherein each of the one or more sutures is secured to one of the joint posts.

4. 4. The implantable medical device of claim 2, wherein each of the one or more sutures extends beyond a corresponding joint post and loops around a base of the stabilizing arch above the corresponding joint post.

5. The implantable medical device of claim 4 , wherein each of the sutures is enclosed within the leaflet secured to each of the coaptation posts.

6. a distal edge of the outer skirt is stitched to the inner skirt; The implantable medical device of any one of claims 2 to 5, wherein a proximal edge of the outer skirt overlies at least a portion of the upper crown portion.

7. The implantable medical device of any one of claims 1 to 6, wherein each of the one or more sutures is adapted to allow a proximal edge of the outer skirt to bulge outward in response to fluid pressure on the outer skirt.

8. The implantable medical device of any one of claims 1 to 7, wherein both ends of each of the one or more sutures are attached to the outer skirt at a single location.

9. 8. The implantable medical device of claim 1, wherein for each of the one or more sutures, a first end of the suture is attached to the outer skirt at a first location and a second end of the suture is attached to the outer skirt at a second location circumferentially spaced from the first location.

10. 1. A replacement heart valve adapted to be implanted within a native heart valve annulus, comprising: an expandable frame adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment, Upper crown part, Lower crown part, a joint post extending proximally from the upper crown portion; and an expandable frame comprising a stabilizing arch extending proximally from a joint post; one or more leaflets fixed relative to the expandable frame; an inner skirt surrounding a portion of the expandable frame; an outer skirt surrounding a portion of the expandable frame, the outer skirt adapted to expand outward in response to fluid pressure on the outer skirt, whereby the outer skirt seals against the native valve annulus.

11. 11. The replacement heart valve of claim 10, wherein the outer skirt is attached to the expandable frame via one or more sutures that secure the outer skirt axially to the expandable frame but allow the outer skirt to move radially relative to the expandable frame.

12. 12. The replacement heart valve of claim 10 or 11, wherein both ends of each of the one or more sutures are attached to the outer skirt at a single location.

13. 1. A replacement aortic valve adapted to be implanted within a native aortic valve annulus, comprising: an expandable frame adapted to expand from a collapsed configuration for delivery to an expanded configuration for deployment, Upper crown part, Lower crown part, a joint post extending proximally from the upper crown portion; and an expandable frame comprising a stabilizing arch extending proximally from a joint post; one or more leaflets fixed relative to the expandable frame; an outer skirt, a sealing skirt surrounding a portion of the expandable frame, the outer skirt adapted to bulge outward in response to aortic pressure on the sealing skirt when the one or more valve leaflets are closed, whereby the sealing skirt seals against the aortic valve annulus.

14. 14. The replacement aortic valve of claim 13, wherein the sealing skirt is attached to the expandable frame via one or more sutures that secure the sealing skirt axially relative to the expandable frame but allow the sealing skirt to move radially relative to the expandable frame.

15. 15. The replacement aortic valve of claim 13 or 14, wherein, for each of the one or more sutures, a first end of the suture is attached to the sealing skirt at a first location and a second end of the suture is attached to the sealing skirt at a second location circumferentially spaced from the first location.

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