Patent Description:
The present invention is directed to heart valve prosthesis, and more particularly to a mitral valve prosthesis for use in a transcatheter mitral valve replacement procedure.

A human heart includes four heart valves that determine the pathway of blood flow through the heart: the mitral valve, the tricuspid valve, the aortic valve, and the pulmonary valve. The mitral and tricuspid valves are atrioventricular valves, which are between the atria and the ventricles, while the aortic and pulmonary valves are semilunar valves, which are in the arteries leaving the heart. Ideally, native leaflets of a heart valve move apart from each other when the valve is in an open position, and meet or "coapt" when the valve is in a closed position. Problems that may develop with valves include stenosis in which a valve does not open properly, and/or insufficiency or regurgitation in which a valve does not close properly. Stenosis and insufficiency may occur concomitantly in the same valve. The effects of valvular dysfunction vary, with regurgitation or backflow typically having relatively severe physiological consequences to the patient.

Recently, prosthetic valves supported by stent structures that can be delivered percutaneously using a catheter-based delivery system have been developed for heart and venous valve replacement. These prosthetic valves may include either self-expanding or balloon-expandable stent structures with valve leaflets attached to the interior of the stent structure. The prosthetic valve can be reduced in diameter, by crimping onto a balloon catheter or by being contained within a sheath component of a delivery catheter, and advanced through the venous or arterial vasculature. Once the prosthetic valve is positioned at the treatment site, for instance within an incompetent native valve, the stent structure may be expanded to hold the prosthetic valve firmly in place. One example of a stented prosthetic valve is disclosed in <CIT>.

Although transcatheter delivery methods may provide safer and less invasive methods for replacing a defective native heart valve, preventing leakage between the implanted prosthetic valve and the surrounding native tissue remains a challenge. Leakage sometimes occurs due to the fact that minimally invasive and percutaneous replacement of cardiac valves typically does not involve actual physical removal of the diseased or injured heart valve. Rather, the replacement stented prosthetic valve is delivered in a compressed condition to the valve site and expanded to its operational state within the discased heart valve, which may not allow complete conformance of the stent frame within the native heart valve and can be a source of paravalvular leakage (PVL). As well PVL may occur after a heart valve prosthesis is implanted due to movement and/or migration of the prosthesis that can occur during the cardiac cycle. Movement due to changes in chordal tensioning during the cardiac cycle may be particularly problematic for mitral valve prosthesis, as chordal tensioning can axially unseat, lift or rock the prosthesis within or into the atrium resulting in PVL. Accordingly, there is a continued need to provide mitral valve prosthesis having structure that maintains sealing within the native anatomy during the cardiac cycle. <CIT> relates to a transcatheter mitral valve prosthesis.

The claimed subject-matter is defined in independent claim <NUM>. <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> do not show all of the claimed features.

Mitral valve prosthesis according to embodiments hereof includes a frame having a flexible, anatomically conforming inflow portion that is designed to maintain scaling with the atrial surface surrounding the native mitral valve during the cardiac cycle. The frame or support structure defines an inflow portion, a valve-retaining tubular portion and a pair of support arms. The inflow portion radially extends from a first end of the valve-retaining tubular portion and the pair of support arms are circumferentially spaced apart and radially extend from an opposing second end of the valve-retaining tubular portion. The inflow portion is formed from a plurality of struts that outwardly extend from the first end of the valve-retaining tubular portion with adjacent struts of the plurality of struts being , wherein each strut of the plurality of struts has a substantially s-shaped profile and at least one twisted arca.

The foregoing and other features and advantages of the invention will be apparent from the following description of embodiments thereof as illustrated in the accompanying drawings.

Specific embodiments of the present invention are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms "distal" and "proximal" are used in the following description with respect to a position or direction relative to the treating clinician. "Distal" or "distally" are a position distant from or in a direction away from the clinician. "Proximal" and "proximally" are a position near or in a direction toward the clinician. In addition, as used herein, the terms "outward" or "outwardly" refer to a position radially away from a longitudinal axis of a frame of the prosthesis and the terms "inward" or "inwardly" refer to a position radially toward a longitudinal axis of the frame of the prosthesis. As well the terms "backward" or "backwardly" refer to the relative transition from a downstream position to an upstream position.

Although the description of embodiments hereof are in the context of treatment of heart valves and particularly a mitral valve, the invention may also be adapted for use in other valve replacement procedures where it is deemed useful.

<FIG> is a perspective sectional view of a heart (H) that depicts a mitral valve (MV) and various structural features related thereto, with <FIG> being a superior view of the mitral valve isolated from surrounding heart structure. The mitral valve is found between the left atrium (not shown) and the left ventricle (LV) and is surrounded by and attached to a fibrous atrioventricular ring of the heart that may be more commonly referred to as the mitral valve annulus (MVA). As best shown in <FIG>, the mitral valve annulus may be considered to have a D-shape rather than being circular or elliptical. The mitral valve includes anterior and posterior leaflets (AL, PL) that open during diastole to allow blood flow from the left atrium to the left ventricle. During ventricular systole, the anterior and posterior leaflets close to prevent backflow to the left atrium while the mitral valve annulus contracts and reduces its surface area to help provide complete closure of the leaflets. The anterior and posterior leaflets are attached to papillary muscles (PM) within the left ventricle by way of the chordae tendinae (CT), which are strong, fibrous strings or structures attached to the leaflets of the heart on the ventricular side. When the anterior and posterior leaflets of the mitral valve close, the chordae tendinac are tensioned to prevent the leaflets from swinging back into the atrium cavity.

Due to the unique shape of a native mitral valve and the functionality of the structure associated therewith that can cause axial movement of a prosthetic mitral valve during the cardiac cycle, i.e., axial movement that may be caused by the cyclic tensioning of the chordae tendinae and/or contraction of the D-shaped mitral valve annulus during ventricular systole, a mitral valve prosthesis according to embodiments hereof includes a frame having a flexible, anatomically conforming inflow portion that is designed to maintain sealing with the atrial surface surrounding the mitral valve during the cardiac cycle.

<FIG> is a side view of a mitral valve prosthesis <NUM> in accordance with an embodiment hereof shown in a deployed configuration, with <FIG> being a top view of an inflow area of prosthesis <NUM> taken in the direction of line A-A in <FIG>. Prosthesis <NUM> includes a valve component <NUM> attached within an interior of a frame or support structure <NUM>. Valve component <NUM> is a one-way bicuspid replacement valve having first and second valve leaflets 224A, 224B. In another embodiment, valve component <NUM> may be a one-way tricuspid replacement valve having three valve leaflets. Valve leaflets 224A, 224B are sutured or otherwise securely and sealingly attached to an interior surface of frame <NUM> and/or to graft material <NUM>, which encloses or lines various portions of frame <NUM>. In embodiments in accordance herewith, graft material <NUM> secured to frame <NUM> within an inflow area of prosthesis <NUM> aids in sealing and graft material <NUM> secured to frame <NUM> proximate an outflow area of prosthesis <NUM> provides a tent-like or hammock structure <NUM>, which functions to reduce or eliminate interaction between frame <NUM> and the chordae tendinae when prosthesis <NUM> is implanted within a native mitral valve.

<FIG>, <FIG> illustrate frame <NUM> in a deployed configuration removed from a remainder of prosthesis <NUM>. <FIG> and <FIG> are side views of frame <NUM>, with <FIG> showing frame <NUM> rotated <NUM>° about a longitudinal axis LA thereof from the orientation shown in <FIG> is a top or inflow view of frame <NUM> taken in the direction of line A-A in <FIG> is a cross-sectional view of a strut 512B of frame <NUM> taken along line B-B in <FIG>. <FIG> is a sectional view of frame <NUM> taken along line A-A in <FIG> is a cross-sectional view of strut 512B of frame <NUM> taken along line B-B in <FIG>.

Frame <NUM> is a unitary structure that defines an inflow portion <NUM>, a valve-retaining tubular portion <NUM> and a pair of support arms 206A, 206B. In the deployed configuration of frame <NUM>, inflow portion <NUM> outwardly extends from a first or inflow end <NUM> of valve-retaining tubular portion <NUM> and support arms 206A, 206B backwardly extend from circumferentially spaced apart locations of an opposing second or outflow end <NUM> of valve-retaining tubular portion <NUM>. When prosthesis <NUM> is implanted within a native mitral valve, inflow portion <NUM> of frame <NUM> is configured to engage an area of the left atrium that surrounds the native mitral valve, valve-retaining tubular portion <NUM> of frame <NUM> is configured to axially extend through the native mitral valve and thusly situates valve component <NUM> within the mitral valve annulus, and support arms 206A, 206B are configured to capture respective valve leaflets of the mitral valve and to secure them within the left ventricle without obstructing the outflow area of prosthesis <NUM> or the left ventricular outflow tract.

Frame <NUM> is a unitary structure, as previously noted above. In an initial step in manufacturing frame <NUM>, a tube <NUM> of a suitable material is etched, cut or otherwise machined to have the pattern depicted in <FIG> depicts for illustrative purposes only patterned tube <NUM> laid flat so that the cut structures of inflow portion <NUM>, valve-retaining tubular portion <NUM> and support arms 206A, 206B may be more readily identified and described. Valve-retaining tubular portion <NUM> has a stent-like framework that defines diamond-shaped openings <NUM> and a series of upstream valleys 514A and downstream valleys 514B. Support arms 206A, 206B are formed from inner and outer looped struts <NUM>, <NUM> with the outer looped struts <NUM> extending from spaced apart valleys 514B of valve-retaining tubular portion <NUM> and with the inner looped struts <NUM> extending from spaced apart downstream peaks <NUM> of valve-retaining tubular portion <NUM>.

Inflow portion <NUM> is formed from a plurality of struts <NUM> having a cut width WC that is less than a thickness T thereof, as shown in <FIG> which is a cross-sectional view of strut 512B taken along line A-A in <FIG>. Each strut <NUM> defines a base segment <NUM> and divergent first and second branch segments 511A, 511B. Accordingly, strut <NUM> may be considered to have a Y-shaped cut pattern. Base segments <NUM> of a respective pair of struts <NUM>, for instance base segments 509A, 509B of struts 512A, 512B, extend from every other valley <NUM> at inflow end <NUM> of valve-retaining tubular portion <NUM>. A plurality of crowns <NUM> are formed between first and second branch segments 511A, 511B of adjacent struts <NUM>. Crowns <NUM> form radially outward ends of inflow portion <NUM> of frame <NUM>, as shown in <FIG>. Circumferentially adjacent crowns <NUM> are not directly connected to each other and thereby provide inflow portion <NUM> with improved flexibility.

Subsequent processing steps are performed on patterned tube <NUM> in order to form frame <NUM> as shown in <FIG>, <FIG>. In one or more processing steps, patterned tube <NUM> is radially expanded to set a tubular shape and diameter of valve-retaining tubular portion <NUM> that is suitable for receiving valve component <NUM> therein. In one or more additional processing steps, support arms 206A, 206B are rotated outward and backward relative to outflow end <NUM> of valve-retaining tubular portion <NUM> and heat treated to set a shape thereof. In one or more additional processing steps, struts <NUM> of inflow portion <NUM> of patterned tube <NUM> are made to outwardly extend from inflow end <NUM> of valve-retaining tubular portion <NUM> and subjected to a forming process to have a substantially s-shaped profile, as best seen in <FIG>. In an embodiment and somewhat counter-intuitively, a first bend 416A and an opposing second bend 416B that form the substantially s-shaped profile of strut <NUM> are bent or curved over the cut width WC of the strut, as shown in <FIG> and <FIG>, rather than being bent or curved over thickness T of the strut. First and second bends 416A, 416B of s-shaped strut <NUM> are able to be formed in this manner due to one or more twisted areas TA<NUM>, TA<NUM>, TA<NUM> of strut <NUM> that occur during formation of inflow portion <NUM>. More particularly with reference to <FIG> and <FIG>, base segment <NUM> of each strut <NUM> has a twisted area TA<NUM> near or adjacent to where the respective base segment <NUM> outwardly extends from inflow end <NUM> of valve-retaining tubular portion <NUM>. Although not intending to be bound by theory, twisted area TA<NUM> turns cut width WC of the respective strut <NUM> approximately <NUM> degrees from the cut pattern shown in <FIG> such that the narrower portion Wc of the respective strut <NUM> is subjected to the forming process that creates first and second bends 416A, 416B. As well with reference to <FIG>, first and second branch segments 511A, 511B of each strut <NUM> have twisted areas TA<NUM>, TA<NUM>, respectively, near or adjacent to their respective crowns <NUM>. Although not intending to be bound by theory, twisted areas TA<NUM>, TA<NUM> turn cut width WC of the respective strut <NUM> in a direction opposite of twisted area TA<NUM> to return cut width WC to a similar orientation as shown in the cut pattern in <FIG>, which results in cut width We facing inward and outward along at least a portion of first and second branch segments 511A, 511B of struts <NUM> and through crowns <NUM> of inflow portion <NUM>.

In the embodiment of frame <NUM> shown in <FIG>, <FIG>, inflow portion <NUM> may be described as having a ring of alternating openings or cells C1, C2 that are formed between respective portions of struts <NUM> and crowns <NUM>. Cells C1, C2 have widths W<NUM>, W<NUM>, respectively, with width W<NUM> of cell C1 being less than width W<NUM> of cell C2, as best shown in <FIG>. Although not intending to be bound by theory, the alternating size of cells C1, C2 contributes to base segments <NUM> that emanate from a common valley <NUM> of tubular portion <NUM> having twisted areas TA<NUM> that twist or turn away from each other, or in other words twist in opposite directions from each other. For example with reference the pair of base segments 509A, 509B shown in <FIG>, <FIG>, twisted area TA<NUM> of base segment 509A will turn strut 512A counterclockwise toward its adjacent cell C2, such that twisted area TA<NUM> of base segment 509A may be considered to have a left-hand twist, and twisted area TA<NUM> of base segment 509B will turn strut 512B clockwise toward its adjacent cell C2, such that twisted area TA<NUM> of base segment 509B may be considered to have a right-hand twist.

The s-shaped struts <NUM> that form inflow portion <NUM> of frame <NUM> act similarly to cantilever beams when interacting with the anatomy of the heart as a supporting and scaling structure of prosthesis <NUM>. During the pressure changes and cyclical contractions of the heart, the s-shaped struts <NUM> are able to deflect while maintaining an axial force against the atrial surface of the heart that is sufficient for sealing and the prevention of paravalvular leakage between the frame and tissue surface. As well the combination of twisted areas TA<NUM>, TA<NUM>, TA<NUM> and s-shape of struts <NUM> of inflow portion <NUM> permit the inflow area of prosthesis <NUM> to readily deflect, flex and/or move during the cardiac cycle while also maintaining sufficient axial stiffness to provide sealing contact with the atrial surface that surrounds the implanted prosthesis. In addition, the twisted areas TA<NUM>, TA<NUM>, TA<NUM> of s-shaped struts <NUM> may reduce strain and improve the structural integrity of frame <NUM>, and more particularly the structural integrity of inflow portion <NUM> thereof.

<FIG> and <FIG> illustrate a frame <NUM> in a deployed configuration in accordance with another embodiment hereof that is suitable for use in forming a mitral valve prosthesis similar to prosthesis <NUM> described above. <FIG> is a side view of frame <NUM>, with <FIG> being a top or inflow view of frame <NUM> taken in the direction of line A-A in <FIG>. Frame <NUM> is a unitary structure that defines an inflow portion <NUM>, a valve-retaining tubular portion <NUM> and a pair of support arms 806A, 806B. In the deployed configuration of frame <NUM>, inflow portion <NUM> outwardly extends from a first or inflow end <NUM> of valve-retaining tubular portion <NUM> and support arms 806A, 806B backwardly extend from circumferentially spaced apart locations of an opposing second or outflow end <NUM> of valve-retaining tubular portion <NUM>. When implanted within a native mitral valve as a support structure of a mitral valve prosthesis, inflow portion <NUM> is configured to engage an area of the left atrium that surrounds the native mitral valve, valve-retaining tubular portion <NUM> is configured to axially extend through the native mitral valve and thusly situates a prosthetic valve component within the mitral valve annulus, and support arms 806A, 806B are configured to capture respective valve leaflets of the mitral valve and to secure them within the left ventricle without obstructing the outflow area of the prosthetic valve or the left ventricular outflow tract.

In an initial step in manufacturing frame <NUM>, a tube <NUM> of a suitable material is etched, cut or otherwise machined to have the pattern depicted in <FIG> depicts for illustrative purposes only patterned tube <NUM> laid flat so that the cut structures of inflow portion <NUM>, valve-retaining tubular portion <NUM> and support arms 806A, 806B may be more readily identified and described. Valve-retaining tubular portion <NUM> has a stent-like framework that defines diamond-shaped openings <NUM> and a series of upstream valleys 914A and downstream valleys 914B. Each support arm 806A, 806B is formed to have inner side struts 913A, 913B and an outer looped strut <NUM>. Outer looped struts <NUM> extend from spaced apart downstream peaks 917B of valve-retaining tubular portion <NUM> and inner side struts 913A, 913B extend from respective downstream valleys 914B within their respective outer looped strut <NUM> and connect therewith at opposing interior locations 919A, 919B. In another embodiment in accordance herewith, tube <NUM> may be cut into a pattern such that frame <NUM> is formed to have support arms 206A, 206B as described with reference to the previous embodiment.

Inflow portion <NUM> is formed from a plurality of struts <NUM> having a cut width WC that is less than a thickness T thereof, as shown in <FIG> which is a cross-sectional view of a strut <NUM> taken along line A-A in <FIG>. Each strut <NUM> defines a base segment <NUM> and first and second branch segments 911A, 911B, which diverge from base segment <NUM> at a respective node <NUM>. Accordingly, strut <NUM> may be considered to have a Y-shaped cut pattern. A base segment <NUM> of a respective strut <NUM> extends from every upstream valley 914A at inflow end <NUM> of valve-retaining tubular portion <NUM>. Each base segment <NUM> has a length that disposes a respective node <NUM> of strut <NUM> upstream of upstream peaks 917A. In an embodiment, base segment <NUM> has a length such that node <NUM> of strut <NUM> is disposed upstream of upstream peaks 917A by at least half a length of the base segment. Crowns <NUM> are formed between first and second branch segments 911A, 911B of adjacent struts <NUM>. Crowns <NUM> form radially outward ends of inflow portion <NUM> of frame <NUM>, as shown in <FIG>. Circumferentially adjacent crowns <NUM> are not directly connected to each other and thereby provide inflow portion <NUM> with improved flexibility.

Subsequent processing steps are performed on patterned tube <NUM> in order to form frame <NUM> as shown in <FIG> and <FIG>. In one or more processing steps, patterned tube <NUM> is radially expanded to set a tubular shape and diameter of valve-retaining tubular portion <NUM> that is suitable for receiving a prosthetic valve component therein. In one or more additional processing steps, support arms 806A, 806B are rotated outward and backward relative to outflow end <NUM> of valve-retaining tubular portion <NUM> and heat treated to set a shape thereof. In one or more additional processing steps, struts <NUM> of inflow portion <NUM> of patterned tube <NUM> are made to outwardly extend from inflow end <NUM> of valve-retaining tubular portion <NUM> and subjected to a forming process to have a substantially s-shaped profile, as best seen in <FIG>. Somewhat counter-intuitively, a first bend 816A and an opposing second bend 816B that form the substantially s-shaped profile of strut <NUM> are bent or curved over the cut width WC of the strut, as shown in <FIG>, rather than being bent or curved over thickness T of the strut. First and second bends 816A, 816B of s-shaped strut <NUM> are able to be formed in this manner due to one or more twisted areas TA<NUM>, TA<NUM>, TA<NUM> of strut <NUM> that occur during formation of inflow portion <NUM>. More particularly with reference to <FIG>, base segment <NUM> of each strut <NUM> has a twisted area TA<NUM> near or adjacent to where the respective base segment <NUM> outwardly extends from inflow end <NUM> of valve-retaining tubular portion <NUM>. Although not intending to be bound by theory, twisted area TA<NUM> turns cut width WC of the respective strut <NUM> approximately <NUM> degrees from the cut pattern shown in <FIG> such that the wider thickness T of the respective strut <NUM> is subjected to the forming process that creates first and second bends 816A, 816B. As well with reference to <FIG>, first and second branch segments 911A, 911B of each strut <NUM> have twisted areas TA<NUM>, TA<NUM>, respectively, near or adjacent to their respective crowns <NUM>. Although not intending to be bound by theory, twisted areas TA<NUM>, TA<NUM> turn cut width WC of the respective strut <NUM> in a direction opposite of twisted area TA<NUM> to return cut width WC to a similar orientation as shown in the cut pattern in <FIG>, which results in cut width Wc facing inward and outward along at least a portion of first and second branch segments 911A, 911B of struts <NUM> and through crowns <NUM> of inflow portion <NUM>.

In the embodiment of frame <NUM> shown in <FIG> and <FIG>, inflow portion <NUM> may be described as having a ring of equal or like sized and shaped cells C1 that are formed between respective portions of struts <NUM> and crowns <NUM>. In contrast to the symmetrical appearance of cells C1, C2 of inflow portion <NUM> of frame <NUM> shown in <FIG>, cells C1 of inflow portion <NUM> of frame <NUM> shown in <FIG> appear to spiral clockwise. Although not intending to be bound by theory, the spiral appearance of inflow portion <NUM> may be the result of all struts <NUM> having twisted areas TA<NUM> that twist or turn in a common or same direction from valve-retaining tubular section <NUM>. In the embodiment shown in <FIG> and <FIG>, the twisted area TA<NUM> of each base segment <NUM> turns the respective strut <NUM> clockwise relative to inflow end <NUM> of valve-retaining portion <NUM> such that twisted area TA<NUM> may be considered to have a right-hand twist. In another embodiment (not shown), the twisted area TA<NUM> of each base segment <NUM> turns the respective strut <NUM> counterclockwise relative to inflow end <NUM> of valve-retaining portion <NUM> such that twisted area TA<NUM> may be considered to have a left-hand twist.

With reference to <FIG>, first bend 816A of each s-shaped strut <NUM> has an apex <NUM> that is longitudinally disposed at or near downstream valleys 914B of valve-retaining tubular portion <NUM>. The increased depth of first bend 816A and the corresponding increased height of second bend 816B, as compared to first and second bends 816A, 816B, respectively, are made possible by the longer length of inflow struts <NUM> relative to an axial length of valve-retaining tubular portion <NUM> as compared to a length of inflow struts <NUM> relative to an axial length of valve-retaining tubular portion <NUM>. In another embodiment, apex <NUM> of first bend 816A may be positioned at or near upstream valleys 914A of valve-retaining tubular portion <NUM>, similar to the location of apex <NUM> of first bend 416A as shown in <FIG> and <FIG>. In other embodiments in accordance herewith, apex <NUM> of s-shaped struts <NUM> and apex <NUM> of s-shaped struts <NUM> may be suitably disposed anywhere along the axial length of valve-retaining tubular portions <NUM>, <NUM>, respectively, in order to tailor the flexibility of the respective inlet portion <NUM>, <NUM> for a particular application.

The s-shaped struts <NUM> that form inflow portion <NUM> of frame <NUM> act similarly to cantilever beams when interacting with the anatomy of the heart as a supporting and sealing structure of a mitral valve prosthesis in accordance with embodiments hereof. During the pressure changes and cyclical contractions of the heart, the s-shaped struts <NUM> are able to deflect while maintaining an axial force against the atrial surface of the heart that is sufficient for sealing and the prevention of paravalvular leakage between the frame and tissue surface. As well the combination of twisted areas TA<NUM>, TA<NUM>, TA<NUM> and the s-shape of struts <NUM> of inflow portion <NUM> permit the inflow area of mitral valve prosthesis in accordance with embodiments hereof to readily deflect, flex and/or move during the cardiac cycle while also maintaining sufficient axial stiffness to provide sealing contact with the atrial surface that surrounds the implanted prosthesis. In addition, the twisted areas TA<NUM>, TA<NUM>, TA<NUM> of s-shaped struts <NUM> may reduce strain and improve the structural integrity of frame <NUM>, and more particularly the structural integrity of inflow portion <NUM> thereof. Another benefit of the design of inflow portion <NUM> of frame <NUM> is that it readily conforms to the D-shape of the mitral valve annulus by allowing deflection or movement in a radial direction DR of struts <NUM> and the cells C1 defined thereby, as shown in <FIG>. <FIG> is a photographic image of an implanted mitral valve prosthesis having a frame <NUM> that shows how individual struts <NUM> have radially deflected or moved after implantation to "lay down" a bit flatter and conform to the D-shape of the native mitral valve annulus. This anatomically conforming feature of frame <NUM> is more clearly depicted in <FIG>, with <FIG> showing the deformation of inflow portion <NUM> of frame <NUM> after implantation and with <FIG> showing the post-implantation deformed inflow portion <NUM> of <FIG> (shown in cyan) transposed on a pre-implantation inflow portion <NUM> of <FIG> (shown in red).

In order to transform between an initial compressed configuration and the deployed configuration shown in the figures hereof, frames <NUM>, <NUM> in accordance with embodiments described herein are formed from a self-expanding material that has a mechanical memory to return to the deployed configuration. Accordingly in accordance with embodiments hereof, frames <NUM>, <NUM> may be made from stainless steel, a pseudo-elastic metal such as a nickel titanium alloy or nitinol, or a so-called super alloy, which may have a base metal of nickel, cobalt, chromium, or other metal. Mechanical memory may be imparted to the tubular structure that forms frames <NUM>, <NUM> by thermal treatment to achieve a spring temper in stainless steel, for example, or to set a shape memory in a susceptible metal alloy, such as nitinol. Mitral valve prosthesis in accordance with embodiments hereof may be delivered via a transapical implantation procedure or via a transatrial implantation procedure. Suitable transapical and/or transatrial implantation procedures that may be adapted for use with mitral valve prosthesis described herein are disclosed in<CIT>, <CIT>, and <CIT>.

In accordance with embodiments hereof, valve leaflets hereof, such as first and second valve leaflets 224A, 224B, may be made of or formed from a natural material obtained from, for example, heart valves, aortic roots, aortic walls, aortic leaflets, pericardial tissue, such as pericardial patches, bypass grafts, blood vessels, intestinal submucosal tissue, umbilical tissue and the like from humans or animals. In accordance with other embodiments hereof, synthetic materials suitable for use as valve leaflets hereof, such as valve leaflets 224A, 224B, include DACRON® polyester commercially available from Invista North America S. of Wilmington, DE, other cloth materials, nylon blends, polymeric materials, and vacuum deposition nitinol fabricated materials. In an embodiment, valve leaflets hereof, such as valve leaflets 224A, 224B, can be made of an ultra-high molecular weight polyethylene material commercially available under the trade designation DYNEEMA from Royal DSM of the Netherlands. With certain leaflet materials, it may be desirable to coat one or both sides of the leaflet with a material that will prevent or minimize overgrowth. It is further desirable that the leaflet material is durable and not subject to stretching, deforming, or fatigue.

In accordance with embodiments hereof, graft material <NUM> or portions thereof may be a low-porosity woven fabric, such as polyester, DACRON® polyester, or polytetrafluoroethylene (PTFE), which creates a one-way fluid passage when attached to frame <NUM>. In an embodiment, graft material <NUM> or portions thereof may be a looser knit or woven fabric, such as a polyester or PTFE knit, which can be utilized when it is desired to provide a medium for tissue ingrowth and the ability for the fabric to stretch to conform to a curved surface. In another embodiment, polyester velour fabrics may alternatively be used for graft material <NUM> or portions thereof, such as when it is desired to provide a medium for tissue ingrowth on one side and a smooth surface on the other side. These and other appropriate cardiovascular fabrics are commercially available from Bard Peripheral Vascular, Inc. of Tempe, AZ, for example. In another embodiment, graft material <NUM> or portions thereof may be a natural material, such as pericardium or another membranous tissue.

In accordance with embodiments hereof, valve-retaining tubular portions and support arms of frames disclosed herein, as well as the graft material and tent-like structures that may be associated therewith, may be modified without departing from the scope of the present invention in view of the disclosures of one or more of<CIT>,<CIT>, and <CIT>.

Claim 1:
A mitral valve prosthesis comprising:
a frame (<NUM>) having an inflow portion (<NUM>), and
a valve-retaining tubular portion (<NUM>),
wherein in a deployed configuration the inflow portion of the frame radially extends from a first end of the valve-retaining tubular portion, and
wherein the inflow portion of the frame comprises a plurality of s-shaped struts (<NUM>) radially extending from the first end of the valve-retaining tubular portion in the deployed configuration,
wherein a graft material (<NUM>) encloses or lines the inflow portion of the frame.