Patent Publication Number: US-2020289262-A1

Title: Anti-paravalvular leakage component for a transcatheter valve prosthesis

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-in-Part of and claims the benefit of U.S. patent application Ser. No. 13/757,380, filed Feb. 1, 2013, the disclosure of which is herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to transcatheter valve prostheses and methods of preventing paravalvular leakage. More specifically, the present invention relates to an anti-paravalvular leakage component integrated on an outer surface of a transcatheter valve prosthesis to seal gaps between a support frame of the prosthesis and native valve tissue. 
     BACKGROUND OF THE INVENTION 
     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, flexible 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 U.S. Pat. No. 5,957,949 to Leonhardt et al. entitled “Percutaneous Placement Valve Stent”, which is incorporated by reference herein in its entirety. Another example of a stented prosthetic valve for a percutaneous pulmonary valve replacement procedure is described in U.S. Patent Application Publication No. 2003/0199971 A1 and U.S. Patent Application Publication No. 2003/0199963 A1, both filed by Tower et al., each of which is incorporated by reference herein in its entirety. 
     Although transcatheter delivery methods have provided safer and less invasive methods for replacing a defective native heart valve, leakage between the implanted prosthetic valve and the surrounding native tissue is a recurring problem. 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, where it is expanded to its operational state within the mitral valve. Calcified or diseased native leaflets are pressed to the side walls of the native valve by the radial force of the stent frame of the prosthetic valve. These calcified leaflets do not allow complete conformance of the stent frame with the native valve and can be a source of paravalvular leakage (PVL). Significant pressure gradients across the valve cause blood to leak through the gaps between the implanted prosthetic valve and the calcified anatomy. 
     Embodiments hereof are related to anti-paravalvular leakage components coupled to an outer surface of the valve prosthesis to seal gaps between the valve prosthesis and native valve tissue. 
     BRIEF SUMMARY OF THE INVENTION 
     Embodiments hereof relate to a transcatheter valve prosthesis including a tubular stent having a compressed configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve, a prosthetic valve component disposed within and secured to the stent, and an anti-paravalvular leakage component coupled to and encircling an outer surface of the tubular stent. The anti-paravalvular leakage component includes a plurality of self-expanding segments and an annular sealing element attached to the segments. A first end and a second end of each segment is attached to the outer surface of the tubular stent at spaced apart first and second attachment points, respectively. The anti-paravalvular leakage component has an expanded configuration in which the segments curve radially away from the outer surface of the tubular stent and are oblique to the outer surface of the tubular stent such that a plane defined by each segment is non-perpendicular with respect to a tangential plane of the tubular stent taken through the first and second attachments points. 
     According to other embodiments hereof, embodiments hereof relate to a transcatheter valve prosthesis including a tubular stent having a compressed configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve, a prosthetic valve component disposed within and secured to the stent, and an anti-paravalvular leakage component coupled to and encircling an outer surface of the tubular stent. The anti-paravalvular leakage component includes a plurality of self-expanding segments and an annular sealing element attached to the segments. A first end and a second end of each segment is attached to the outer surface of the tubular stent at spaced apart first and second attachment points, respectively. The anti-paravalvular leakage component has an expanded configuration in which the segments curve radially away from the outer surface of the tubular stent, and the flexibility of the anti-paravalvular leakage component at the plurality of segments varies around the circumference of the tubular stent when the anti-paravalvular leakage component is in the expanded configuration. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The foregoing and other features and advantages of the invention will be apparent from the following description of embodiments hereof as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. The drawings are not to scale. 
         FIG. 1  is a side view illustration of an exemplary transcatheter heart valve prosthesis for use in embodiments hereof. 
         FIG. 1A  is a top view illustration of the heart valve prosthesis of  FIG. 1 . 
         FIG. 1B  is a side view illustration of an alternative configuration of a heart valve prosthesis for use in embodiments hereof. 
         FIG. 1C  is a side view illustration of an alternative configuration of a heart valve prosthesis for use in embodiments hereof. 
         FIG. 2  is a side view illustration of the heart valve prosthesis of  FIG. 1  implanted within a native valve annulus. 
         FIG. 3  is a side view of the heart valve prosthesis of  FIG. 1  having an anti-paravalvular leakage component coupled thereto, wherein the anti-paravalvular leakage component includes a annular scaffold and an impermeable membrane that covers an outer surface of the annular scaffold. 
         FIG. 4  is a perspective view of the annular scaffold of the anti-paravalvular leakage component of  FIG. 3 . 
         FIG. 5  illustrates the annular scaffold of the anti-paravalvular leakage component of  FIG. 3  laid flat out for illustrative purposes. 
         FIG. 5A  is a cross-sectional view taken along line A-A of  FIG. 5 . 
         FIG. 6  is a side view illustration of the heart valve prosthesis of  FIG. 3 , having an anti-paravalvular leakage component coupled thereto, implanted within a native valve annulus. 
         FIG. 7  is a perspective view of an annular scaffold for use in an anti-paravalvular leakage component, according to another embodiment hereof, wherein the annular scaffold includes an increased number of peaks and valleys relative to the annular scaffold of  FIG. 4 . 
         FIG. 8  is a perspective view of an annular scaffold for use in an anti-paravalvular leakage component, according to another embodiment hereof, wherein the annular scaffold includes peaks that curve or bow radially outward. 
         FIG. 9  is a side view illustration of an anti-paravalvular leakage component which used the annular scaffold of  FIG. 8  implanted within a native valve annulus. 
         FIG. 10  is a perspective view of an annular scaffold for use in an anti-paravalvular leakage component, according to another embodiment hereof, wherein the annular scaffold includes a combination of peaks that curve radially inward and peaks that curve radially outward. 
         FIG. 11  is a side view illustration of a heart valve prosthesis, having an anti-paravalvular leakage component coupled thereto, implanted within a native mitral valve annulus. 
         FIG. 12  is a side view of a heart valve prosthesis having an anti-paravalvular leakage component coupled thereto according to another embodiment hereof, wherein the anti-paravalvular leakage component includes a plurality of self-expanding segments and an annular sealing element coupled to an inside surface of the segments. 
         FIG. 12A  is an end view of  FIG. 12  taken along line A-A of  FIG. 12 . 
         FIG. 13  is side view of the heart valve prosthesis of  FIG. 12  in a deployed or expanded configuration, with the annular sealing element removed for clarity. 
         FIG. 13A  illustrates the length of a diamond-shaped opening of a stent when the heart valve prosthesis of  FIG. 13  is in a deployed or expanded configuration. 
         FIG. 14  is a side view of the heart valve prosthesis of  FIG. 13  in a compressed or delivery configuration. 
         FIG. 14A  illustrates the length of a diamond-shaped opening of a stent when the heart valve prosthesis of  FIG. 13  is in a compressed or delivery configuration. 
         FIG. 15  is a side view of a heart valve prosthesis having an anti-paravalvular leakage component coupled thereto according to another embodiment hereof, wherein the anti-paravalvular leakage component includes a plurality of self-expanding segments that extend over two longitudinally adjacent diamond-shaped openings of a stent. 
         FIG. 15A  illustrates the length of a diamond-shaped opening of a stent when the heart valve prosthesis of  FIG. 15  is in a deployed or expanded configuration. 
         FIG. 15B  illustrates the length of a diamond-shaped opening of a stent when the heart valve prosthesis of  FIG. 1S  is in a compressed or delivery configuration. 
         FIG. 16  is a side view of a heart valve prosthesis having two anti-paravalvular leakage components coupled thereto according to another embodiment hereof. 
         FIG. 17  is a side view of a heart valve prosthesis having an anti-paravalvular leakage component coupled thereto according to another embodiment hereof, wherein the anti-paravalvular leakage component includes a plurality of oblique self-expanding segments and an annular sealing element coupled to an inside surface of the segments. 
         FIG. 17A  is an end view of  FIG. 17  taken along line A-A of  FIG. 17 . 
         FIG. 17B  is an end view of  FIG. 17  taken along line A-A of  FIG. 17  according to an alternative embodiment hereof in which the annular sealing element is coupled to an outer surface of the segments. 
         FIG. 17C  is an end view of  FIG. 17  taken along line A-A of  FIG. 17  according to an alternative embodiment hereof in which the annular sealing element is formed via the graft material of the heart valve prosthesis. 
         FIG. 18  is a side view of the heart valve prosthesis having an anti-paravalvular leakage component coupled thereto according to another embodiment hereof, wherein the anti-paravalvular leakage component includes a plurality of oblique self-expanding segments and the annular sealing element has been removed for clarity. 
         FIGS. 19A-19B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 20A-20B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 21A-21B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 22A-22B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 23A-23B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 24A-248  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stem. 
         FIGS. 25A-25B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 26A-26B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 27A-27B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 28A-28B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 29A-29B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIGS. 30A-30B  illustrate front and side views, respectively, of one or more diamond-shaped openings of a stent, wherein an oblique self-expanding segment according to another embodiment hereof is coupled to the stent. 
         FIG. 31  is an enlarged side view of a portion of a stent, wherein each diamond-shaped opening of the stent includes two oblique self-expanding segments according to an embodiment hereof. 
         FIGS. 32A-32B  are front and side views, respectively, of a diamond-shaped opening of the stent of  FIG. 31 . 
         FIG. 33  is a side view of a heart valve prosthesis having two anti-paravalvular leakage components coupled thereto according to another embodiment hereof, wherein the anti-paravalvular leakage components each include a plurality of oblique self-expanding segments and the annular sealing elements have been removed for clarity. 
         FIG. 34  is an end view of an anti-paravalvular leakage component coupled to a tubular stent according to an embodiment hereof, wherein the anti-paravalvular leakage component includes zones or sections of differing flexibility and radial force. 
         FIG. 35  is an end view of an anti-paravalvular leakage component coupled to a tubular stent according to another embodiment hereof, wherein the anti-paravalvular leakage component includes zones or sections of differing flexibility and radial force. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Specific embodiments of the present invention are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. If utilized herein, the terms “distal” or “distally” refer to a position or in a direction away from the heart and the terms “proximal” and “proximally” refer to a position near or in a direction toward the heart. The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description of the invention is in the context of treatment of heart valves, the invention may also be used where it is deemed useful in other valved intraluminal sites that are not in the heart. For example, the present invention may be applied to venous valves as well. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
       FIG. 1  depicts an exemplary transcatheter heart valve prosthesis  100 . Heart valve prosthesis  100  is illustrated herein in order to facilitate description of the methods and devices to prevent and/or repair paravalvular leakage according to embodiments hereof. It is understood that any number of alternate heart valve prostheses can be used with the methods and devices described herein. Heart valve prosthesis  100  is merely exemplary and is described in more detail in U.S. Patent Application Pub. No. 2011/0172765 to Nguyen et al., which is herein incorporated by reference in its entirety. 
     Heart valve prosthesis  100  includes an expandable stent or frame  102  that supports a prosthetic valve component within the interior of stent  102 . In embodiments hereof, stent  102  is self-expanding to return to an expanded deployed state from a compressed or constricted delivery state and 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. “Self-expanding” as used herein means that a structure/component has a mechanical memory to return to the expanded or deployed configuration. Mechanical memory may be imparted to the wire or tubular structure that forms stent  102  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, or a polymer, such as any of the polymers disclosed in U.S. Pat. Appl. Pub. No. 2004/0111111 to Lin, which is incorporated by reference herein in its entirety. Alternatively, heart valve prosthesis  100  may be balloon-expandable as would be understood by one of ordinary skill in the art. 
     In the embodiment depicted in  FIGS. 1 and 1A , stent  102  of valve prosthesis  100  has a deployed asymmetric hourglass configuration including an enlarged first end or section  116 , a constriction or waist region  117 , and a second end or section  118 . Enlarged first section  116  has nominal deployed diameter D 1 , second section  118  has nominal deployed diameter D 2 , and constriction region  117  has deployed substantially fixed diameter D 3 . Each section of stent  102  may be designed with a number of different configurations and sizes to meet the different requirements of the location in which it may be implanted. When configured as a replacement for an aortic valve, second section  118  functions as an inflow end of heart valve prosthesis  100  and extends into and anchors within the aortic annulus of a patient&#39;s left ventricle, while first section  116  functions as an outflow end of heart valve prosthesis  100  and is positioned in the patient&#39;s ascending aorta. When configured as a replacement for a mitral valve, enlarged first section  116  functions as an inflow end of heart valve prosthesis  100  and is positioned in the patient&#39;s left atrium, while second section  118  functions as an outflow end of heart valve prosthesis  100  and extends into and anchors within the mitral annulus of a patient&#39;s left ventricle. For example, U.S. Patent Application Publication Nos. 2012/0101572 to Kovalsky et al. and 2012/0035722 to Tuval, each of which are herein incorporated by reference in their entirety, illustrate heart valve prostheses configured for placement in a mitral valve. Each section of stent  102  may have the same or different cross-section which may be for example circular, ellipsoidal, rectangular, hexagonal, rectangular, square, or other polygonal shape, although at present it is believed that circular or ellipsoidal may be preferable when the valve prosthesis is being provided for replacement of the aortic or mitral valve. As alternatives to the deployed asymmetric hourglass configuration of  FIGS. 1 and 1A , the stent/valve support frame may have a symmetric hourglass configuration  102 B shown in  FIG. 1B , a generally tubular configuration  102 C as shown in  FIG. 1C , or other stent configuration or shape known in the art for valve replacement. Stent  102  also may include eyelets  108  that extend from first end  116  thereof for use in loading the heart valve prosthesis  100  into a delivery catheter (not shown). 
     As previously mentioned, heart valve prosthesis  100  includes a prosthetic valve component within the interior of stent  102 . The prosthetic valve component is capable of blocking flow in one direction to regulate flow through heart valve prosthesis  100  via valve leaflets  104  that may form a bicuspid or tricuspid replacement valve.  FIG. 1A  is an end view of  FIG. 1  and illustrates an exemplary tricuspid valve having three leaflets  104 , although a bicuspid leaflet configuration may alternatively be used in embodiments hereof. More particularly, if heart valve prosthesis  100  is configured for placement within a native valve having three leaflets such as the aortic, tricuspid, or pulmonary valves, heart valve prosthesis  100  may include three valve leaflets  104 . If heart valve prosthesis  100  is configured for placement within a native valve having two leaflets such as the mitral valve, heart valve prosthesis  100  may include two valve leaflets  104 . Valve leaflets  104  are sutured or otherwise securely and sealingly attached to the interior surface of stent  102  and/or graft material  106  which encloses or lines stent  102  as would be known to one of ordinary skill in the art of prosthetic tissue valve construction. Referring to  FIG. 1 , leaflets  104  are attached along their bases  110  to graft material  106 , for example, using sutures or a suitable biocompatible adhesive. Adjoining pairs of leaflets are attached to one another at their lateral ends to form commissures  120 , with free edges  122  of the leaflets forming coaptation edges that meet in area of coaptation  114 . 
     Leaflets  104  may be made of pericardial material; however, the leaflets may instead be made of another material. Natural tissue for replacement valve leaflets may be 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. Synthetic materials suitable for use as leaflets  104  include DACRON® polyester commercially available from Invista North America S.A.R.L. of Wilmington, Del., other cloth materials, nylon blends, polymeric materials, and vacuum deposition Nitinol fabricated materials. One polymeric material from which the leaflets can be made is 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. 
     Graft material  106  may also be a natural or biological material such as pericardium or another membranous tissue such as intestinal submucosa. Alternatively, graft material  106  may be a low-porosity woven fabric, such as polyester, Dacron fabric, or PTFE, which creates a one-way fluid passage when attached to the stent. In one embodiment, graft material  106  may be a knit or woven polyester, 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. Polyester velour fabrics may alternatively be used, 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, Ariz., for example. 
     Delivery of heart valve prosthesis  100  may be accomplished via a percutaneous transfemoral approach or a transapical approach directly through the apex of the heart via a thoracotomy, or may be positioned within the desired area of the heart via different delivery methods known in the art for accessing heart valves. During delivery, if self-expanding, the prosthetic valve remains compressed until it reaches a target diseased native heart valve, at which time the heart valve prosthesis  100  can be released from the delivery catheter and expanded in situ via self-expansion. The delivery catheter is then removed and heart valve prosthesis  100  remains deployed within the native target heart valve. Alternatively, heart valve prosthesis  100  may be balloon-expandable and delivery thereof may be accomplished via a balloon catheter as would be understood by one of ordinary skill in the art. 
       FIG. 2  is a side view illustration of heart valve prosthesis  100  implanted within a native heart valve, which is shown in section, having native leaflets L N  and corresponding native sinuses S N . When heart valve prosthesis  100  is deployed within the valve annulus of a native heart valve, stent  102  expands within native valve leaflets L N  of the patient&#39;s defective valve, retaining the native valve leaflets in a permanently open state. The native valve annulus may include surface irregularities on the inner surface thereof, and as a result one or more gaps or cavities/crevices  226  may be present or may form between the perimeter of heart valve prosthesis  100  and the native valve annulus. For example, calcium deposits may be present on the native valve leaflets (e.g., stenotic valve leaflets) and/or shape differences may be present between the native heart valve annulus and prosthesis  100 . More particularly, in some cases native annuli are not perfectly rounded and have indentations corresponding to the commissural points of the native valve leaflets. As a result, a prosthesis having an approximately circular shape does not provide an exact fit in a native valve. These surface irregularities, whatever their underlying cause, can make it difficult for conventional prosthetic valves to form a blood tight seal between the prosthetic valve and the inner surface of the valve annulus, causing undesirable paravalvular leakage and/or regurgitation at the implantation site. 
     Embodiments hereof relate to methods for delivering a heart valve prosthesis having a self-expanding anti-paravalvular leakage component thereon that functions to occlude or fill gaps between the perimeter of a heart valve prosthesis and the native valve annulus, thereby reducing, minimizing, or eliminating leaks there through. An anti-paravalvular leakage component  330  is shown in  FIG. 3  in its deployed or expanded configuration, extending around an outer surface or perimeter  103  of heart valve prosthesis  100  to prevent paravalvular leakage in situ. Anti-paravalvular leakage component  330  extends in a radially outward direction relative to outer surface  103  of heart valve prosthesis  100 , and exerts a radial pressure onto a native valve annulus when deployed in situ. More particularly, an expanded or deployed outer diameter of anti-paravalvular leakage component  330  is predetermined to be greater than the expanded outer diameter of stent  102 . When deployed, anti-paravalvular leakage component  330  radially expands into and substantially fills any/all gaps or cavities/crevices between outer surface  103  of stent  102  and native valve tissue. “Substantially” as utilized herein means that blood flow through the target gap or cavity is occluded or blocked, or stated another way blood is not permitted to flow there through. Anti-paravalvular leakage component  330  blocks blood flow around the outer perimeter of prosthesis  100 , thereby minimizing and/or eliminating any paravalvular leakage at the implantation site. 
     More particularly, anti-paravalvular leakage component  330  includes a radially-compressible ring or annular scaffold  332  (shown in phantom in  FIG. 3 ) that is operable to self-expand and an impermeable or semi-impermeable membrane  340  that covers or extends over an outer surface of annular scaffold  332 . Annular scaffold  332  is shown removed from anti-paravalvular leakage component  330  in  FIG. 4 . In addition,  FIG. 5  shows annular scaffold  332  laid flat out for illustrative purposes, while  FIG. 5A  is a cross-sectional view taken along line A-A of  FIG. 5 . Annular scaffold  332  has sufficient radial spring force and flexibility to conformingly engage impermeable membrane  340  within a native heart valve annulus. Suitable materials for impermeable membrane  340  include but are not limited to impermeable or semi-impermeable materials such as a low-porosity woven fabric, such as polyester, Dacron fabric, or PTFE. Porous materials advantageously provide a medium for tissue ingrowth. Further, impermeable membrane  340  may be pericardial tissue or may be a knit or woven polyester, such as a polyester or PTFE knit, both of which provide a medium for tissue ingrowth and have the ability to stretch to conform to a curved surface. Polyester velour fabrics may alternatively be used, such as when it is desired to provide a medium for tissue ingrowth on one side and a smooth surface on the other side. Impermeable membrane  340  is coupled to annular scaffold  332  via sutures or other suitable mechanical connection. 
     With reference to  FIGS. 4 and 5 , annular scaffold  332  is a sinusoidal patterned ring with a plurality of peaks  334 , a plurality of valleys  336 , and a plurality of segments  338  with peaks  334  and valleys  336  being formed between a pair of adjacent segments  338  as shown in  FIG. 4 . Peaks and valleys  334 ,  336  are bends or turns of the scaffold having opposing orientations. In the embodiment depicted in  FIGS. 4 and 5 , annular scaffold  332  includes six peaks  334  and six valleys  336 . However, it would be obvious to one of ordinary skill in the art that the annular scaffold may include a higher or lower number of peaks and valleys. For example,  FIG. 7  illustrates an embodiment in which an annular scaffold  732  includes eight peaks  734  and eight valleys  736 . Conformability of the annular scaffold increases with a higher or increased number of peaks and valleys; however, the annular scaffold is more radially-compressible or collapsible for delivery with a lower or decreased number of peaks and valleys. In an embodiment, the annular scaffold includes between four and eighteen pairs of peaks and valleys. 
     In the embodiment depicted in  FIG. 3 , segments  338  bow or curve radially outward while both peaks  332  and valleys  334  bend or curve radially inward toward stent  102 . Outer surface  342  of each segment  338  is convex, while an inner surface  344  of each segment  338  is concave. In one embodiment hereof, only peaks  332  are coupled to stent  102  while valleys  334  are unattached or free. In another embodiment hereof, only valleys  334  are coupled to stent  102  while peaks  332  are unattached or free. When only one end of annular scaffold  332  is constrained, i.e., either peaks  332  or valleys  334 , the opposing unattached or free end of the annular scaffold is unconstrained, highly flexible, and has an ability to conform to an outer sheath utilized in deployment thereof. More particularly, the unattached peaks or valleys of the annular scaffold slide or ride along outer surface  103  of stent  102  when an outer sheath is advanced over the stent to compress/collapse heart valve prosthesis  100  for delivery. By sliding along outer surface  103  of stent  102 , annular scaffold  332  and therefore anti-paravalvular leakage component  330  approaches a substantially linear delivery configuration within the outer sheath. When the outer sheath is retracted to deploy heart valve prosthesis  100 , the unattached or free peaks or valleys of the annular scaffold return to their preset expanded or deployed shape because annular scaffold  332  is formed from a material having a mechanical memory. Mechanical memory may be imparted to annular scaffold  332  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 NiTi (Nitinol). In an alternate embodiment, a mechanical memory to return to the preset expanded or deployed shape may be imparted to a shape memory polymer that forms annular scaffold  332 , such as any of the polymers disclosed in U.S. Pat. Appl. Pub. No. 2004/0111111 to Lin, which is herein incorporated by reference in its entirety. 
     In an embodiment, anti-paravalvular leakage component  330  is coupled to heart valve prosthesis  100  after manufacture of heart valve prosthesis  100 . In another embodiment, anti-paravalvular leakage component  330  is manufactured in conjunction with, i.e., at the same time as, heart valve prosthesis  100 . Regardless of whether anti-paravalvular leakage component  330  is formed concurrently with or subsequent to heart valve prosthesis  100 , annular scaffold  332  of anti-paravalvular leakage component  330  may be formed from a single, continuous wire that may be solid or hollow and may have a different cross-section and/or size from stent  102  of heart valve prosthesis  100 . More particularly, in an embodiment, stent  102  is formed via laser-cut manufacturing method and therefore a strut of the stent may have a non-circular cross-section, e.g., a square, rectangular, or polygonal cross-section, and a thickness ranging between 0.011-0.018 inches. Annular scaffold  332  may be formed from a single, continuous wire having a circular or round cross-section as shown in  FIG. 5A  with a diameter between 0.005-0.015 inches. In another embodiment, the cross-section of the wire that forms annular scaffold  332  may be an oval, elliptical, rectangular or ribbon-like, or any other suitable shape. By forming annular scaffold  332  of a relatively thinner or smaller wire as compared to a strut of stent  102 , annular scaffold  332  has greater flexibility to conform to the inner surface of the native valve annulus including any surface irregularities that may be present, thereby filling any gaps or cavities/crevices that may be present between the heart valve prosthesis  100  and native tissue, while the thicker struts of stent  102  provide sufficient radial force to deploy the heart valve prosthesis into apposition with the native valve annulus. In another embodiment hereof, annular scaffold  332  of anti-paravalvular leakage component  330  may be integrally formed with stent  102  of heart valve prosthesis via a laser-cut manufacturing method. If integrally formed with stent  102 , the cross-section of the wire/strut of annular scaffold  332  may be the same size and shape as a strut of the stent or may be of a different size and/or shape as the strut of the stent. 
     Shown deployed within an aortic valve in  FIG. 6 , segments  338  of annular scaffold  332  protrude radially outward from heart valve prosthesis  100  to easily conform to calcified anatomy of the native valve while impermeable membrane  340  provides a mechanical barrier to the blood flowing through any gaps or cavities/crevices present between the heart valve prosthesis and the native valve tissue. Antegrade blood flow BF is illustrated by directional arrows in  FIG. 6 . Annular scaffold  332  is radially and circumferentially compliant due to its relatively small wire size, as described herein. With such maximized conformability, anti-paravalvular leakage component  330  functions as a continuous circumferential seal around the heart valve prosthesis to prevent or block blood flow between the outer surface or perimeter of the heart valve prosthesis and a native heart valve annulus. 
     In the embodiment of  FIGS. 3-6 , anti-paravalvular leakage component  330  is coupled to outer surface  103  of heart valve prosthesis  100  adjacent to second end  118  thereof. When deployed, anti-paravalvular leakage component  330  may be positioned in situ at the native valve annulus, slightly above the valve annulus, slightly below the valve annulus, or some combination thereof. Since the annular anti-paravalvular leakage component is coupled to outer surface  103  of heart valve prosthesis  100 , longitudinal placement and/or the size and shape thereof is flexible and may be adjusted or adapted according to each application and to a patient&#39;s unique needs. For example, depending on the anatomy of the particular patient, the anti-paravalvular leakage component may be positioned on heart valve prosthesis  100  so that in situ the anti-paravalvular leakage component is positioned between heart valve prosthesis  100  and the interior surfaces of the native valve leaflets, between heart valve prosthesis  100  and the interior surfaces of the native valve annulus, and/or between heart valve prosthesis  100  and the interior surfaces of the left ventricular outflow track (LVOT). 
     The shape or configuration of the annular scaffold may be optimized based on the design and application of the heart valve prosthesis. In another embodiment hereof depicted in  FIGS. 8 and 9 , an annular scaffold  832  includes segments  838  that curve or flare radially outward between valleys  836  that bend or curve radially inward for attachment to a stent of a heart valve prosthesis and peaks  834  that flare or curve radially outward. Outer surface  842  of each segment  838  is concave, while an inner surface  844  of each segment  838  is convex. Since only valleys  834  are coupled/constrained to the heart valve prosthesis and peaks  832  are unconstrained or free and highly flexible, annular scaffold  832  has an ability to conform to an outer sheath utilized in deployment thereof as described above. 
       FIG. 9  illustrates an anti-paravalvular leakage component  830  coupled to heart valve prosthesis  100 , which is deployed within an aortic valve having native valve leaflets L N . Anti-paravalvular leakage component  830  includes an impermeable membrane  840  coupled to an outer surface of annular scaffold  832 , thereby forming an open-ended pocket or compartment  833  around stent  102  between an inner surface of anti-paravalvular leakage component  830  and outer surface  103  of heart valve prosthesis  100 . Open-ended pocket  833  catches and blocks any retrograde flow within the aortic valve, thereby preventing undesired regurgitation and preventing blood stagnation in and around the native valve sinuses. In addition, the configuration of anti-paravalvular leakage component  830 , formed by flared, unconstrained peaks  834  and impermeable membrane  840  coupled to the outside surface of the annular scaffold, diverts or deflects antegrade blood flow away from heart valve prosthesis  100 . Antegrade blood flow BF A  is illustrated with a directional arrow in  FIG. 9 . By diverting or deflecting antegrade blood flow away from the heart valve prosthesis and catching retrograde blood flow with open-ended pocket  833 , anti-paravalvular leakage component  830  formed with annular scaffold  832  functions as a continuous circumferential seal around the heart valve prosthesis to prevent or block blood flow between the outer surface or perimeter of the heart valve prosthesis and a native heart valve annulus. 
     In yet another embodiment hereof, the anti-paravalvular leakage component may include two or more adjacent annular scaffolds. The adjacent annular scaffolds may have the same configuration, i.e., two adjacent annular scaffold  332  or two adjacent annular scaffold  832 , or the adjacent annular scaffold may have different configurations. For example,  FIG. 10  illustrates a heart valve prosthesis  1000  having a first annular scaffold  1032 A and a second annular scaffold  1032 B. Heart valve prosthesis  1000  includes a support frame or stent  1002  and a valve component  1004  secured therein, but graft material adjacent to a second end  1018  thereof is not shown for sake of clarity. Annular scaffold  1032 A is similar to annular scaffold  332  and includes segments that bow or bulge radially outward while both peaks and valleys thereof bend or curve radially inward toward heart valve prosthesis  1000 . Annular scaffold  1032 B is similar to annular scaffold  832  and includes segments that are curved or flare radially outward between valleys that bend or curve radially inward for attachment to heart valve prosthesis  1000  and unconstrained peaks that flare or curve radially outward. Although not shown for sake of clarity, an impermeable membrane is coupled to each of annular scaffolds  1032 A,  1032 B to form two anti-paravalvular leakage components as described herein with respect to annular scaffolds  332 ,  832 , respectively. In addition, although shown with annular scaffold  10328  adjacent to second end  1018  of heart valve prosthesis  1000 , it will be apparent to one of ordinary skill in the art that annular scaffold  1032 A may alternatively be located closer to second end  1018  than annular scaffold  10321 . The adjacent annular scaffolds may be positioned such their peaks and valleys are in phase with each other, or out of phase with each other for improved compressibility/collapsibility. 
     Although embodiments depicted herein illustrate an anti-paravalvular leakage component integrated onto a heart valve prosthesis configured for implantation within an aortic valve, it would be obvious to one of ordinary skill in the art that an anti-paravalvular leakage component as described herein may be integrated onto a heart valve prosthesis configured for implantation implanted within other heart valves. For example,  FIG. 11  illustrates an anti-paravalvular leakage component  1130  coupled to the outer surface or perimeter of a heart valve prosthesis  1100  implanted within a mitral valve. 
       FIG. 12  illustrates an anti-paravalvular leakage component  1230 , in its expanded or deployed configuration, coupled to a heart valve prosthesis  1200  according to another embodiment hereof. In this embodiment, anti-paravalvular leakage component  1230  includes a plurality of independent, self-expanding segments  1250  and an annular sealing element  1260 . Annular sealing element  1260  is coupled to inner surfaces  1252  of segments  1250 , and when the segments radially expand or deploy as described in more detail herein, annular sealing element  1260  is positioned between an outer surface  1203  of heart valve prosthesis  1200  and inner surfaces  1252  of the segments. As such, annular sealing element  1260  extends around the outer surface or perimeter of heart valve prosthesis  1200  and extends into and substantially fills any/all gaps or cavities/crevices between outer surface  1203  of heart valve prosthesis  1200  and native valve tissue to prevent paravalvular leakage in situ. In an embodiment hereof, annular sealing element  1260  may be formed from a swellable material that collapses easily and expands to a larger volume after implantation, such as but not limited to hydrogel or a collagen foam/sponge similar to the material commercially available under the trademark Angioseal. Other suitable material examples for annular sealing element  1260  include tissue, compressible foam materials, fabric, or compressible polymeric materials. 
     Segments  1250  are coupled to an outer surface  1203  of heart valve prosthesis  1200 . More particularly, first and second ends  1254 ,  1256  of segments  1250  are coupled to an outer surface  1203  of heart valve prosthesis  1200  via welding, sutures, or other suitable mechanical method. In another embodiment hereof, segments  1250  may be integrally formed with stent  1202  of heart valve prosthesis. Segments  1250  are spaced apart in approximately equal intervals or segments around heart valve prosthesis  1200  as shown in  FIG. 12A , which is an end view taken along line A-A of  FIG. 12 . In another embodiment hereof, the segments may be spaced apart in non-equal intervals or segments around the outside of the heart valve prosthesis. For example, it may be desirable to position one or more segments at a location on the heart valve prosthesis corresponding to an area prone to leakage in situ, such as adjacent to the native valve commissures. Although shown with eight segments  1250 , it will be understood by one of ordinary skill in the art that a greater or lesser number of segments may be utilized herein. 
     As best shown in  FIG. 13 , in which annular sealing element  1260  has been removed for clarity, ends  1254 ,  1256  of each segment  1250  are coupled to opposing peaks or apexes of a diamond-shaped opening  1258  of stent  1202  of heart valve prosthesis  1200 . In this embodiment, segments  1250  are coupled to diamond-shaped openings adjacent to end  1218  of heart valve prosthesis  1200  but it will be understood that the segments may be coupled to diamond-shaped openings anywhere along the length of stent  1202 . The longitudinal position of anti-paravalvular leakage component  1230  on heart valve prosthesis  1200  may vary depending upon application and configuration of the heart valve prosthesis. Coupling each segment  1250  to opposing peaks or apexes of a diamond-shaped opening  1258  of stent  1202  allows each segment to utilize the foreshortening of stent  1202  to its advantage because each segment  1250  aligns and packs/collapses within its corresponding opening  1258  when heart valve prosthesis  1200  is crimped for delivery. More particularly, as shown in  FIG. 14 , when heart valve prosthesis  1200  is crimped onto a catheter (not shown) for delivery thereof, openings  1258  are longitudinally stretched and elongate to a length L 2 , which is shown in  FIG. 14A . An arc length of each segment  1250  is approximately equal to length L 2 , the crimped length of opening  1258  such that each segment  1250  is stretched flat or flush over its corresponding opening  1258  when crimped. Stated another way, each segment  1250  is straightened when heart valve prosthesis  1200  is crimped for delivery and the straightened segment  1250  is in line or flush with the crimped stent  1202 . When each segment  1250  is stretched flat or flush over its corresponding opening  1258 , the material of annular sealing element  1260  is compressed and pulled inside stent  1202  via openings  1258 . Accordingly, the addition of anti-paravalvular leakage component  1230  advantageously does not increase, or minimally increases, the packing profile of heart valve prosthesis  1200  so that heart valve prosthesis  1200  has the ability to pack in lower profile delivery systems. 
     When heart valve prosthesis  1200  is deployed, as shown in  FIG. 13 , stent  1202  foreshortens and the length of openings  1258  return to their deployed length L 1 , which is shown in  FIG. 13A . Segment  1250 , and annular sealing member  1260  attached thereto, self-expand radially outward as shown in  FIG. 12  and  FIG. 13 . An outer surface  1259  of each segment is convex, while the inner surface  1252  of each segment is concave. Similar to segments  338  of annular scaffold  332  described with respect to  FIG. 6  herein, segments  1250  bow or curve radially outward to easily conform to calcified anatomy of the native valve while annular sealing member  1260  provides a mechanical barrier to the blood flowing through any gaps or cavities/crevices present between the heart valve prosthesis and the native valve tissue. In this embodiment, since annular sealing member  1260  is positioned between segments  1250  and prosthesis  1200 , the sealing member is protected from being unintentionally moved or shifted during delivery. 
     Similar to previous embodiments described herein, anti-paravalvular leakage component  1230  may be formed concurrently with or subsequent to heart valve prosthesis  1200  and each segment  1250  of anti-paravalvular leakage component  1230  may be formed from a wire that may be solid or hollow and may have a different cross-section and/or size from stent  1202  of heart valve prosthesis  1200 . For example, segments  1250  may be formed of a relatively thinner or smaller wire as compared to a strut of stent  1202  such that anti-paravalvular leakage component  1230  has greater flexibility to conform to the inner surface of the native valve annulus including any surface irregularities that may be present, thereby filling any gaps or cavities/crevices that may be present between the heart valve prosthesis  1200  and native tissue, while the thicker struts of stent  1202  provide sufficient radial force to deploy the heart valve prosthesis into apposition with the native valve annulus. 
     Segments  1250  are radially-compressible and self-expanding. In order to self-expand, segments  1250  may be made from a metallic material having a mechanical memory to return to the preset expanded or deployed shape. Mechanical memory may be imparted to segments  1250  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 NiTi (Nitinol) or Co—Cr (Cobalt-Chrome). In an alternate embodiment, a mechanical memory to return to the preset expanded or deployed shape may be imparted to a shape memory polymer that forms segments  1250 , such as any of the polymers disclosed in U.S. Pat. Appl. Pub. No. 2004/0111111 to Lin, which is herein incorporated by reference in its entirety. 
     It will be understood by one of ordinary skill in the art that the length of anti-paravalvular leakage component  1230  is not limited to the embodiment shown in  FIG. 12 . For example, as shown in the embodiment of  FIG. 15 , in which the annular sealing element has been removed for clarity, each segment  1250  may extend over two openings  1558  of a stent  1502  of a heart valve prosthesis  1500 . Ends  1554 ,  1556  of each segment  1550  are coupled to opposing peaks or apexes of two longitudinally-adjacent diamond-shaped opening  1558 . As explained above, each segment  1550  aligns and packs/collapses within its corresponding openings  1558  when heart valve prosthesis  1500  is crimped for delivery. An arc length of each segment  1550  is approximately equal to length L 2 , the crimped length of two longitudinally-adjacent diamond-shaped openings  1558 , as shown in  FIG. 15B . When heart valve prosthesis  1500  is deployed, as shown in  FIG. 15 , stent  1502  foreshortens and the length of two longitudinally-adjacent diamond-shaped openings  1558  return to their deployed length L 1 , which is shown in  FIG. 15A . Segment  1550 , and the annular sealing member attached thereto, self-expand or bow radially outward to conform to the anatomy of the native valve. 
     In addition, two or more anti-paravalvular leakage components may be included on a heart valve prosthesis. For example,  FIG. 16  illustrates a heart valve prosthesis  1600  having a first anti-paravalvular leakage component  1630 A and a second anti-paravalvular leakage component  1630 B. Although not shown for sake of clarity, an annular sealing element is coupled inside surfaces of segments  1650 A,  1650 B to form two anti-paravalvular leakage components  1630 A,  1630 B, respectively, as described herein with respect to anti-paravalvular leakage component  1230 . Segments  1650 A,  1650 B are shown coupled to adjacent rows of openings  1658  of stent  1602  such that anti-paravalvular leakage components  1630 A,  16301 B are abutting against each other, but anti-paravalvular leakage components  1630 A,  1630 B may alternatively be positioned at longitudinally spaced apart locations on heart valve prosthesis  1600 . 
     In the embodiments of  FIGS. 12-16 , segments of the anti-paravalvular leakage components in the expanded configuration are orthogonal to the outer surface of the tubular stent. “Orthogonal” to the outer surface of the tubular stent as used herein means that a plane defined by each expanded segment is perpendicular with respect to a tangential plane of the tubular stent taken through the first and second attachments points. When positioned in situ, deformation of the valve prosthesis by the surrounding native anatomy as an orthogonal force may require straightening of the orthogonal segment and distortion of the tubular stent to which the segment is attached. However, in another embodiment hereof, when the anti-paravalvular leakage component is in the expanded configuration the segments may be oblique to the outer surface of the tubular stent. “Oblique” to the outer surface of the tubular stent as used herein means that a plane defined by each segment is non-perpendicular with respect to a tangential plane of the tubular stent taken through the first and second attachments points. The plane defined by each segment may form an angle between 20 and 80 degrees with respect to a tangential plane of the outer surface of the tubular stent. When positioned in situ, deformation of the valve prosthesis by the surrounding native anatomy as a non-orthogonal force results in bending or pivoting of the oblique segments at the first and second attachments points, thereby increasing conformability of the anti-paravalvular leakage component with respect to the surrounding native anatomy. Further, since oblique segments bend or pivot rather than flatten to accommodate the surrounding native anatomy, such bending does not distort the tubular stent and the oblique segments may be designed independently of the tubular frame to optimize force and movement thereof for sealing purposes. 
     More particularly,  FIGS. 17 and 17A  illustrate an embodiment hereof in which an anti-paravalvular leakage component  1730 , in its expanded or deployed configuration, includes a plurality of independent, self-expanding segments  1750  that are oblique to an outer surface  1703  of a tubular stent  1702  of a heart valve prosthesis  1700 . Similar to anti-paravalvular leakage component  1230 , anti-paravalvular leakage component  1730  includes segments  1750  and an annular sealing element  1760 . Segments  1750  are coupled to outer surface  1703  of heart valve prosthesis  1700 , and an outer surface  1759  of each segment is convex while the inner surface  1752  of each segment is concave. More particularly, first and second ends  1754 ,  1756  of segments  1750  are coupled to an outer surface  1703  of heart valve prosthesis  1700  via welding, sutures, or other suitable mechanical method. In another embodiment hereof, segments  1750  may be integrally formed with stent  1702  of heart valve prosthesis. In this embodiment, ends  1754 ,  1756  of each segment  1750  are coupled to opposing peaks or apexes of a diamond-shaped opening  1758  of stent  1702  of heart valve prosthesis  1700 . Since ends  1754 ,  1756  of each segment  1750  are coupled to opposing peaks or apexes of a diamond-shaped opening  1758 , ends  1754 ,  1756  are coupled to stent  1702  at axially spaced apart locations but are not circumferentially spaced apart. In further embodiments that will be described in more detail below, the ends of each segment may be coupled to the stent at axially spaced apart and circumferentially spaced apart locations. Further, in this embodiment, segments  1750  are coupled to diamond-shaped openings adjacent to end  1718  of heart valve prosthesis  1700  but it will be understood that the segments may be coupled to diamond-shaped openings anywhere along the length of stent  1702 . The longitudinal position of anti-paravalvular leakage component  1730  on heart valve prosthesis  1700  may vary depending upon application and configuration of the heart valve prosthesis. 
     As best shown in  FIG. 17A , segments  1750  in the expanded or deployed configuration are oblique to outer surface  1703  of tubular stent  1702 . More particularly, each segment  1750  in the expanded or deployed configuration defines a first plane  1751 . A second or tangential plane  1753  of stent  1702  is taken through the first and second attachments points of ends  1754 ,  1756  of each segment  1750 . First plane  1751  as defined by expanded segment  1750  forms an angle Θ with second or tangential plane  1753  of stent  1702  and is non-perpendicular with respect to second or tangential plane  1753  of stent  1702 . In an embodiment hereof, angle Θ may range between 1 and 89 degrees. In an embodiment hereof, angle Θ may range between 20 and 80 degrees. As angle Θ increases, the radial height or distance of segment  1750  with respect to the outer surface  1703  of tubular stent  1702  increases. More particularly, the angle, height, length, and/or geometry of segment  1750  are all parameters that may be modified to optimize the stress and/or bending movement experienced by segment  1750 , as well as the force exerted by segment  1750 , when segment  1750  is positioned in situ to accommodate the surrounding native anatomy for sealing purposes. Stated another way, the angle, height, length, and/or geometry of segment  1750  are parameters that may be modified in order for segment  1750  to achieve optimal sealing performance in sir. 
     Segments  1750  are spaced apart in approximately equal intervals or segments around heart valve prosthesis  1700  as shown in  FIG. 17A , which is an end view taken along line A-A of  FIG. 17 . In another embodiment hereof, the segments may be spaced apart in non-equal intervals or segments around the outside of the heart valve prosthesis. For example, as will be explained in more detail herein, it may be desirable to position one or more segments at a location on the heart valve prosthesis corresponding to an area prone to leakage in situ, such as adjacent to the native valve commissures Although shown with eight segments  1750 , it will be understood by one of ordinary skill in the art that a greater or lesser number of segments may be utilized herein. Conformability of the anti-paravalvular leakage component increases with a higher or increased number of segments; however, the anti-paravalvular leakage component is more radially-compressible or collapsible for delivery with a lower or decreased number of segments. 
     As shown in  FIG. 17A , annular sealing element  1760  is coupled to inner surfaces  1752  of segments  1750 , and when the segments radially expand or deploy, annular sealing element  1760  is positioned between outer surface  1703  of heart valve prosthesis  1700  and inner surfaces  1752  of the segments. As such, annular sealing element  1760  circumferentially surrounds or extends around the outer surface or perimeter of heart valve prosthesis  1700  and extends into and substantially fills any/all gaps or cavities/crevices between outer surface  1703  of heart valve prosthesis  1700  and native valve tissue to prevent paravalvular leakage in situ. Since annular sealing member  1760  is positioned between segments  1750  and prosthesis  1700 , the sealing member is protected from being unintentionally moved or shifted during delivery. In an embodiment hereof, annular sealing element  1760  may be formed from a swellable material that collapses easily and expands to a larger volume after implantation, such as but not limited to hydrogel or a collagen foam/sponge similar to the material commercially available under the trademark Angioseal. Other suitable material examples for annular sealing element  1760  include tissue, compressible foam materials, fabric, or compressible polymeric materials. 
     In another embodiment hereof shown in  FIG. 17B , anti-paravalvular leakage component  1730 B includes annular sealing element  1760 B and oblique segments  1750 B. Annular sealing element  1760 B is coupled to outer surfaces of segments  1750 B to form an impermeable or semi-permeable membrane that covers or extends over segments  1750 B. Segments  17508  protrude radially outward from the tubular stent to easily conform to calcified anatomy of the native valve while annular sealing element  1760 B provides a mechanical barrier to the blood flowing through any gaps or cavities/crevices present between the heart valve prosthesis and the native valve tissue. Since annular sealing member  1760 B is positioned over segments  1750 B, the sealing member advantageously does not increase, or minimally increases, the packing profile of the heart valve prosthesis so that the heart valve prosthesis has the ability to pack in lower profile delivery systems. Suitable materials for annular sealing element  1760 B include but are not limited to impermeable or semi-permeable materials such as a low-porosity woven fabric, such as polyester, Dacron fabric, or PTFE. Porous materials advantageously provide a medium for tissue ingrowth. Further, annular sealing element  1760 B may be pericardial tissue or may be a knit or woven polyester, such as a polyester or PTFE knit, both of which provide a medium for tissue ingrowth and have the ability to stretch to conform to a curved surface. Polyester velour fabrics may alternatively be used, such as when it is desired to provide a medium for tissue ingrowth on one side and a smooth surface on the other side. Annular sealing element  1760 B is coupled to segments  17508  via sutures or other suitable mechanical connection. 
     In another embodiment hereof, the graft material of the heart valve prosthesis may form the annular sealing element of the anti-paravalvular leakage component. More particularly, as shown in the embodiment of  FIG. 17C , anti-paravalvular leakage component  1730 C includes oblique segments  1750 C which are coupled or attached to graft material  1706 C which encloses or lines stent  1702 C of the heart valve prosthesis. For example, segments  1750 C may be stitched to graft material  1706 C. In one embodiment, graft material  1706 C may be selected so as to have the ability to stretch during deployment of the heart valve prosthesis. In another embodiment, the heart valve prosthesis may be configured with extra or additional graft material  1706 C, e.g., folds, which may be pulled out during deployment of the heart valve prosthesis. When deployed, graft material  1706 C which is coupled to segments  1750 C is pulled radially away from the outer surface of stent  1702 C such that the graft material forms an impermeable or semi-permeable membrane that provides a mechanical barrier to the blood flowing through any gaps or cavities/crevices present between the heart valve prosthesis and the native valve tissue. When graft material  1706 C lines stent  1702 C, and thus is coupled to an inside surface thereof, graft material  1706 C may be pulled through the diamond-shaped openings or cells formed within stent  1702 C. Since the graft material of the heart valve prosthesis forms the annular sealing member, this embodiment advantageously does not increase the packing profile of the heart valve prosthesis so that the heart valve prosthesis has the ability to pack in lower profile delivery systems. 
     The oblique self-expanding segments of  FIG. 17  may have other configurations, and the size, shape, or configuration of the annular scaffold may be optimized based on the design and application of the heart valve prosthesis.  FIGS. 18-30B  illustrate various exemplary configurations for oblique self-expanding segments utilized in embodiments hereof. For example,  FIG. 18  depicts a plurality of independent, self-expanding segments  1850  that are oblique to an outer surface  1803  of a tubular stent  1802 . In  FIG. 18 , the annular sealing component of the anti-paravalvular leakage component has been removed for clarity. Similar to previous embodiments, first and second ends  1854 ,  1856  of segments  1850  are coupled to or formed integrally with an outer surface  1803  of tubular stem  1802 . In this embodiment, however, ends  1854 ,  1856  of each segment  1850  are not coupled to opposing peaks or apexes of a diamond-shaped opening  1858  of stent  1802  but rather are coupled to adjacent or consecutive sides of the diamond-shaped opening  1858 . Accordingly, the length or size of segments  1850  are shorter or less than the length or size of segments  1750 . Ends  1854 ,  1856  are coupled to stent  1802  at axially-spaced apart locations but are not circumferentially spaced apart. In this embodiment, segments  1850  are coupled to adjacent sides of the right half or portion of diamond-shaped opening  1858 , but it will be understood that the segments may be coupled to the opposing or left half of the diamond-shaped opening as shown in  FIGS. 19A-19B .  FIGS. 19A-198 , which are front and side views of an isolated diamond-shaped opening  1958  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  1950  is coupled to adjacent or consecutive sides on the left half or portion of the diamond-shaped opening  1958 . Ends  1954 ,  1956  of segment  1950  are coupled to diamond-shaped opening  1958  at axially-spaced apart locations but are not circumferentially spaced apart. Segment  1950  is shown in its expanded or deployed configuration. 
       FIGS. 20A-20B , which are front and side views of an isolated diamond-shaped opening  2058  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2050  is coupled to opposing peaks or apexes of a diamond-shaped opening  2058 . In this embodiment, however, only a middle portion  2061  of segment  2050  bends or curves radially away from the outer surface of the tubular stent rather than the full or entire length of the segment. Accordingly, the length or size of the radially-extending portions, i.e., middle portions  2061 , of segments  2050  is shorter or less than the full length or size of segments  2050 . Ends  2054 ,  2056  of segment  2050  are coupled to diamond-shaped opening  2058  at axially-spaced apart locations but are not circumferentially spaced apart. Segment  2050  is shown in its expanded or deployed configuration. 
       FIGS. 21A-21B , which are front and side views of an isolated diamond-shaped opening  2158  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2150  is coupled to diagonally-opposing sides of a diamond-shaped opening  2158 . Ends  2154 ,  2156  of segment  2150  are coupled to diamond-shaped opening  2158  at axially spaced apart locations and circumferentially spaced apart locations. Segment  2150  is shown in its expanded or deployed configuration. 
       FIGS. 22A-22B , which are front and side views of an isolated diamond-shaped opening  2258  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2250  is coupled to adjacent or consecutive sides of a diamond-shaped opening  2158 . In this embodiment, however, a middle portion  2261  of segment  2250  has a different curvature than the remaining length of the segment. Stated another way, middle portion  2261  of segment  2250  includes an additional bump or bulge along the length of segment  2250 . Ends  2154 ,  2256  of segment  2250  are coupled to diamond-shaped opening  2258  at axially-spaced apart locations but are not circumferentially spaced apart. Segment  2250  is shown in its expanded or deployed configuration. 
       FIGS. 23A-23B , which are front and side views of an isolated diamond-shaped opening  2358  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2350  is coupled to diagonally-opposing sides of a diamond-shaped opening  2358 . In this embodiment, segment  2350  has a sinusoidal or wavy configuration along the length thereof. Ends  2354 ,  2356  of segment  2350  are coupled to diamond-shaped opening  2358  at axially spaced apart locations and circumferentially spaced apart locations. Segment  2350  is shown in its expanded or deployed configuration. 
       FIGS. 24A-24B , which are front and side views of an isolated diamond-shaped opening  2458  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2450  is U-shaped and coupled to opposing sides of a diamond-shaped opening  2458 . Ends  2454 ,  2456  of segment  2450  are coupled to diamond-shaped opening  2458  at circumferentially spaced apart locations but not axially spaced apart locations. Segment  2450  is shown in its expanded or deployed configuration. U-shaped as used herein includes segments having two opposing side portions  2463 A,  24638  with ends that converge together from a bottom or apex curved portion  2465 . As will be understood by those of ordinary skill in the art, “side” and “bottom” are relative terms and utilized herein for illustration purposes only. The two opposing side portions  2463 A,  2463 B of the U-shaped segment  2450  may be slanted or angled relative to each other, as shown in  FIG. 24A , or may extend parallel to each other. Further, the U-shaped segment  2450  may be considerably longer, shorter, wider, or narrower than shown. In this embodiment, as best shown in the side view of  FIG. 24B , U-shaped segment  2450  flares radially outward such that bottom or apex curved portion  2465  is most radially spaced away from the stent. An outer surface  2459  of U-shaped segment  2450  is concave, while an inner surface  2452  of U-shaped segment  2450  is convex. However, the U-shaped segment may have other expanded or deployed configurations such as the one shown in  FIGS. 25A-25B .  FIGS. 25A-25B , which are front and side views of an isolated diamond-shaped opening  2558  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2550  is U-shaped and coupled to opposing sides of a diamond-shaped opening  2558 . Ends  2554 ,  2556  of segment  2550  are coupled to diamond-shaped opening  2558  at circumferentially spaced apart locations but not axially spaced apart locations. Segment  2550  is shown in its expanded or deployed configuration. In this embodiment, U-shaped segment  2550  curves radially outward such that at least portions of opposing side portions  2563 A,  2563 B as well as bottom curved portion  2565  are most radially spaced away from the stent. An outer surface  2559  of U-shaped segment  2550  is convex, while an inner surface  2552  of U-shaped segment  2550  is concave. 
       FIGS. 26A-26B , which are front and side views of two isolated diamond-shaped openings  2658 A,  2658 B of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2650  is U-shaped and coupled to adjacent sides of diamond-shaped openings  2658 A,  26588 . Ends  2654 ,  2656  of segment  2650  are coupled to and span across diamond-shaped openings  2658 A,  2658 B at circumferentially spaced apart locations but not axially spaced apart locations. Segment  2650  is shown in its expanded or deployed configuration. In this embodiment, as best shown in the side view of  FIG. 268 , U-shaped segment  2650  flares radially outward such that bottom or apex curved portion  2665  is most radially spaced away from the stent similar to U-shaped segment  2450  described above. However, the U-shaped segment may have other expanded or deployed configurations such as the one shown in  FIGS. 27A-27B .  FIGS. 27A-27B , which are front and side views of two isolated diamond-shaped openings  2758 A,  2758 B illustrate another embodiment hereof in which an oblique self-expanding segment  2750  is U-shaped and U-shaped segment  2750  curves radially outward such that at least portions of opposing side portions  2763 A,  2763 B as well as bottom curved portion  2765  are most radially spaced away from the stent similar to U-shaped segment  2550  described above. 
       FIGS. 28A-28B , which are front and side views of two isolated diamond-shaped openings  2858 A,  2858 B of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2650  is coupled to adjacent peaks or apexes of diamond-shaped openings  2858 A,  2858 B. Ends  2854 ,  2856  of segment  2850  are coupled to and span across diamond-shaped openings  2858 A,  28588  at circumferentially spaced apart locations but not axially spaced apart locations. Segment  2850  is shown in its expanded or deployed configuration. 
       FIGS. 29A-29B , which are front and side views of two isolated diamond-shaped openings  2958 A,  29588  of a stent, illustrate another embodiment hereof in which an oblique self-expanding segment  2950  is coupled to adjacent peaks or apexes of diamond-shaped openings  2958 A,  2958 B. In this embodiment, however, only a middle portion  2961  of segment  2950  extends radially away from the outer surface of the tubular stent rather than the full or entire length of the segment. Ends  2954 ,  2956  of segment  2950  are coupled to and span across diamond-shaped openings  2958 A,  2958 B at circumferentially spaced apart locations but not axially spaced apart locations. Segment  2950  is shown in its expanded or deployed configuration. Middle portion  2961  may be oriented to extend or curve away from diamond-shaped openings  2958 A,  2958 B as shown in  FIG. 29A . In another embodiment hereof, shown in  FIGS. 30A-30B , a middle portion  3061  of an oblique self-expanding segment  3050  may be oriented to extend or curve towards diamond-shaped openings  3058 A,  30588 . 
       FIGS. 31, 32A, and 32B  illustrate another embodiment hereof in which two oblique self-expanding segments  3150  are coupled to a single diamond-shaped opening  3158  of a stent  3102 .  FIG. 31  is an enlarged view of a portion of stent  3102 , with each diamond-shaped opening  3158  including two oblique self-expanding segments  3150 . In  FIG. 31 , the annular sealing component of the anti-paravalvular leakage component has been removed for clarity.  FIGS. 32A-32B  are front and side views of an isolated diamond-shaped opening  3158  of stent  3102 . Ends  3154 ,  3156  of each segment  3150  are coupled to adjacent or consecutive sides of diamond-shaped opening  3158  at axially spaced apart locations and circumferentially spaced apart locations. Segments  3150  are shown in their expanded or deployed configuration. Providing two oblique segments that extend over one diamond-shaped opening of the tubular stent provides additional structure or support for the anti-paravalvular leakage component, and conformability of the anti-paravalvular leakage component increases due to the higher or increased number of segments. The anti-paravalvular leakage component may include two segments extending over each diamond-shaped opening around the circumference of the tubular stent as shown in  FIG. 31 , or may include two segments extending over select diamond-shaped openings around the circumference of the tubular stent. For example, it may be desirable to position two segments extending over select diamond-shaped openings at a location on the heart valve prosthesis corresponding to an area prone to leakage in situ, such as adjacent to the native valve commissures. 
     In addition, similar to described above with respect to  FIG. 16 , two or more anti-paravalvular leakage components may be included on a heart valve prosthesis.  FIG. 33  illustrates a stent  3302  for a heart valve prosthesis, the stent including a first anti-paravalvular leakage component  3330 A and a second anti-paravalvular leakage component  3330 B. Although not shown for sake of clarity, an annular sealing element is coupled to segments  3350 A,  3350 B to form two anti-paravalvular leakage components  3330 A,  3330 B, respectively. Segments  3350 A,  3350 B are oblique to an outer surface  3303  of tubular stent  3302 , and are shown coupled to adjacent rows of diamond-shaped openings  3358  of stent  3302  such that anti-paravalvular leakage components  3330 A,  33308  are abutting against each other. In another embodiment hereof (now shown), anti-paravalvular leakage components  3330 A,  3330 B may alternatively be positioned at longitudinally spaced apart locations on tubular stent  3302 . 
     In embodiments hereof, it may be desirable for the flexibility or conformability of the anti-paravalvular leakage component at the plurality of segments to vary around the circumference of the tubular stent when the anti-paravalvular leakage component is in the expanded configuration. For example, it may be desirable to have one or more segments with increased flexibility or conformability (and lower radial force) over select diamond-shaped openings at a location on the heart valve prosthesis such that the segment(s) may better conform to the inner surface of the native valve annulus including any surface irregularities that may be present, thereby filling any gaps or cavities/crevices that may be present between the heart valve prosthesis and native tissue. Conversely, segments with less flexibility or conformability provide sufficient radial force to deploy the anti-paravalvular leakage component into apposition with the native valve annulus. Thus, the anti-paravalvular leakage component may be modified to have at least one segment having lower radial force and greater flexibility to better accommodate the surrounding native anatomy while maintaining high radial force and apposition in the rest of the anti-paravalvular leakage component. Stated another way, the anti-paravalvular leakage component may be considered to have regions or zones having greater flexibility and less radial force as compared to the rest of the anti-paravalvular leakage component. In addition, zones or sections of differing flexibility and radial force may be configured to minimize impingement of the conduction system. More particularly, the force exerted or applied by the segments may be varied to circumferentially to reduce the force applied to the vessel wall and thus minimize impingement of the conduction system. 
     According to an embodiment hereof, in order to accomplish the zones or sections of differing flexibility and radial force, the number or frequency of self-expanding segments may be varied over select diamond-shaped openings at a location on the heart valve prosthesis corresponding to an area prone to leakage in situ. Conformability of the anti-paravalvular leakage component increases at the locations on the heart valve prosthesis having a higher or increased number of segments. In one embodiment hereof, the number or frequency of the segments is the highest at portions of the tubular stent that are prone to leakage in situ, such as adjacent to the native valve commissures or adjacent to areas having relatively greater levels of calcification. More particularly, as shown for example in  FIG. 34 , anti-paravalvular leakage component  3430  for a tubular stent  3402  that includes a plurality of oblique self-expanding segments  3450 A,  3450 B and an annular sealing element  3460  coupled to an outside surface of the segments. Segments  3450 A are similar to segments  3150  described above in that two segments  3450 A extend over a single diamond-shaped opening of tubular stent  3402 , while segments  34501 B are single segments extending over a single diamond-shaped opening of tubular stent  3402 . In one embodiment hereof, segments  3450 A are positioned or located at portions of tubular stent  3402  that are prone to leakage in situ, such as adjacent to the native valve commissures. 
     According to another embodiment hereof, the configurations of self-expanding segments may be varied in order to accomplish the zones or sections of differing flexibility and radial force. More particularly, various properties and/or designs of the self-expanding segments may be varied in order to selectively increase or decrease the flexibility or conformability of a particular segment. The plurality of segments may have different oblique angles, sizes or lengths, shapes or designs, and/or may be formed with different thicknesses in order to selectively increase or decrease the flexibility or conformability of a particular segment. For example, decreasing the angle of an oblique segment relative to the outer surface of the stent generally increases flexibility and conformability of the segment. In comparison, increasing the angle of an oblique segment results in less flexibility but greater radial force to ensure that the anti-paravalvular leakage component seals against the native anatomy. In another example, increasing the length of the segment generally increases flexibility and conformability of the segment. In comparison, shorter segments are less flexible but provide greater radial force. In another example, decreasing the thickness of the segment or a portion of the segment generally increases flexibility and conformability of the segment. In comparison, thicker segments are less flexible but provide greater radial force. In another example, material of the segment, i.e., spring steel verses Nitinol, may selectively impact the flexibility thereof. Other variations or modifications of the segments may be used to provide the anti-paravalvular leakage component with zones with different flexibilities, including but not limited to selecting any of the different shapes or designs of oblique segments described herein for its particular flexibility properties. 
     More particularly, as shown for example in  FIG. 35 , anti-paravalvular leakage component  3530  for a tubular stent  3502  that includes a plurality of oblique self-expanding segments  3550 A,  3550 B and an annular sealing element  3560  coupled to an outside surface of the segments. Segments  3550 A are of a first configuration having a first flexibility or conformability, while segments  3550 B are of a second configuration having a second flexibility or conformability that is different from the first flexibility. In one embodiment hereof, segments  3550 A are more flexible than segments  3550 B and are positioned or located at portions of tubular stent  3502  that are prone to leakage in situ, such as adjacent to the native valve commissures. As described above, one or more properties and/or designs such as the oblique angle, size or length, shape or design, and/or thickness of the self-expanding segments may be varied in order to selectively increase or decrease the flexibility or conformability of a particular segment. Although anti-paravalvular leakage component  3530  is shown with oblique self-expanding segments, one or more of the segments may be orthogonal to the tubular stent as described above with respect to segments  1250   
     While various embodiments according to the present invention have been described above, it should be understood that they have been presented by way of illustration and example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the appended claims and their equivalents. It will also be understood that each feature of each embodiment discussed herein, and of each reference cited herein, can be used in combination with the features of any other embodiment. All patents and publications discussed herein are incorporated by reference herein in their entirety.