Patent Publication Number: US-2021186694-A1

Title: Elliptical heart valve prostheses, delivery systems, and methods of use

Description:
FIELD OF THE INVENTION 
     The present invention relates to elliptical heart valve prostheses, and systems and methods for delivering and deploying elliptical heart valve prostheses. More particularly, the present invention relates to an elliptical shaped heart valve prosthesis wherein the width of the struts of the heart valve prosthesis are varied to form the elliptical shape. 
     BACKGROUND OF THE INVENTION 
     The human heart is a four chambered, muscular organ that provides blood circulation through the body during a cardiac cycle. The four main chambers include the right atria and the right ventricle which supplies the pulmonary circulation, and the left atria and the left ventricle which supplies oxygenated blood received from the lungs to the remaining body. To ensure that blood flows in one direction through the heart, atrioventricular valves (tricuspid and mitral valves) are present between the junctions of the atria and the ventricles, and semi-lunar valves (pulmonary valve and aortic valve) govern the exits of the ventricles leading to the lungs and the rest of the body. These valves contain leaflets or cusps that open and shut in response to blood pressure changes caused by the contraction and relaxation of the heart chambers. The leaflets move apart from each other to open and allow blood to flow downstream of the valve, and coapt to close and prevent backflow or regurgitation in an upstream manner. 
     Diseases associated with heart valves, such as those caused by damage or a defect, can include stenosis and valvular insufficiency or regurgitation. For example, valvular stenosis causes the valve to become narrowed and hardened which can prevent blood flow to a downstream heart chamber from occurring at the proper flow rate and may cause the heart to work harder to pump the blood through the diseased valve. Valvular insufficiency or regurgitation occurs when the valve does not close completely, allowing blood to flow backwards, thereby causing the heart to be less efficient. A diseased or damaged valve, which can be congenital, age-related, drug-induced, or in some instances caused by infection, can result in an enlarged, thickened heart that loses elasticity and efficiency. Some symptoms of heart valve diseases can include weakness, shortness of breath, dizziness, fainting, palpitations, anemia and edema, and blood clots which can increase the likelihood of stroke or pulmonary embolism. Symptoms can often be severe enough to be debilitating and/or life threatening. 
     In recent years, heart valve prostheses for percutaneous transcatheter delivery and implantation have been developed. The heart valve prosthesis is radially compressed or collapsed for delivery in a catheter and then advanced, for example through an opening in the femoral artery, through the aorta, where the valve prosthesis is then deployed in the annulus of a native heart valve. Valve prostheses are generally formed by attaching a prosthetic valve to a frame or stent made of a wire or a network of wires. The valve prosthesis may be deployed by radially expanding it once positioned at the desired deployment site. 
     Most heart valve prostheses are of a circular cross-section. However, a large population of patients have bicuspid valves that are non-circular, or elliptical in shape. Round or circular heart valve prostheses deployed within a noncircular or elliptical native anatomy have an increased potential for para-valvular leakage (PVL), a serious post-implantation condition. Accordingly, there is a need for improved, elliptical shaped heart valve prostheses, and systems and methods for deploying elliptical shaped heart valve prostheses. 
     BRIEF SUMMARY OF THE INVENTION 
     Embodiments hereof relate to a heart valve prosthesis include a frame including a lumen, and a prosthetic valve disposed within the lumen of the frame. The frame further includes a plurality of struts forming a plurality of crowns, an inflow end, and an outflow end opposite the inflow end. The frame further includes a radially collapsed state and a radially expanded state. A stiffness of the plurality of struts is varied such that when the frame is in the radially expanded state, the frame is substantially elliptically shaped in cross-section. 
     In any of the embodiments, the stiffness of the plurality of struts may be varied by varying a width of at least one strut of the plurality of struts such that when the frame is in the radially expanded state, at least one strut with a greatest width of the plurality of struts is disposed adjacent a major axis of the frame, and at least one strut with a smallest width of the plurality of struts is disposed adjacent a minor axis of the frame. 
     In any of the embodiments, the width of each strut of the plurality of struts of the frame may be selected from a group consisting of a first strut width, a second strut width, a third strut width, a fourth strut width, and a fifth strut width. 
     In any of the embodiments, at least one of the inflow end or the outflow end of the frame comprises eighteen crowns formed by struts of the plurality of struts. In any of the embodiments, the plurality of struts forming the eighteen crowns each have a width selected from a group consisting of a first width, a second width, a third width, a fourth width, and a fifth width. In any of the embodiments, each of the eighteen crowns are formed by two struts such that the plurality of struts consists of thirty-six struts including four struts of the first width, eight struts of the second width, eight struts of the third width, eight struts of the fourth width, an eight struts of the fifth width, wherein the second width is greater than the first width, the third width is greater than the second width, the fourth width is greater than the third width, and the fifth width is greater than the fourth width. In any of the embodiments, the crowns formed by the struts with the fifth width are disposed adjacent a minor axis of the frame and the crowns formed by the struts with the first width are disposed adjacent a major axis of the frame. 
     In any of the embodiments, when the frame is in the radially collapsed state, the plurality of crowns at at least one of the inflow end or the outflow end are non-planar, and when the frame is in the radially expanded state the plurality of crowns at the at least one of the inflow end or the outflow end are substantially planar. 
     In any of the embodiments, the plurality of struts at the inflow end and the plurality of struts at the outflow end may be of a non-uniform length. 
     In any of the embodiments, at least one of the inflow end or the outflow end comprises crowns of the plurality of crowns, and the plurality of struts forming the crowns at the outflow end or the inflow end each have a width selected from a group consisting of a first width, a second width, a third width, a fourth width, and a fifth width. 
     In any of the embodiments, the prosthetic valve may comprise four leaflets. 
     In any of the embodiments, the frame may be balloon expandable. 
     Embodiments hereof relate to a system for percutaneously delivering a heart valve prosthesis to a site of a native heart valve. The system includes a delivery catheter and a heart valve prosthesis in a radially collapsed configuration for delivery disposed at a distal portion of the delivery catheter. The heart valve prosthesis includes a radially expanded configuration wherein the heart valve prosthesis has a substantially elliptical shape, the substantially elliptical shape formed by varying a stiffness of at least one strut of a plurality of struts of a frame of the heart valve prosthesis. 
     In any of the embodiments, the stiffness of the at least one strut may be varied by changing a width of the at least one strut. In any of the embodiments, when the heart valve prosthesis is in the radially expanded configuration, at least one strut with a greatest width of the plurality of struts is disposed adjacent a minor axis of the heart valve prosthesis, and at least one strut with a smallest width of the plurality of struts is disposed adjacent a major axis of the heart valve prosthesis. 
     In any of the embodiments, the heart valve prosthesis may be balloon expandable, the delivery catheter may comprise a balloon at a distal portion thereof with an inflated state in which the balloon is substantially elliptically shaped in cross-section, and the heart valve prosthesis in the radially collapsed configuration may be disposed over the balloon in an uninflated state such that a major axis of the heart valve prosthesis is circumferentially aligned with a major axis of the balloon. 
     In any of the embodiments, the delivery catheter may further include a radiopaque marker coupled thereto and aligned with the major axis of the balloon. 
     Embodiments hereof also relate to method of deploying a substantially elliptically shaped heart valve prosthesis. The method includes loading a substantially elliptically shaped heart valve prosthesis in a radially collapsed configuration onto a delivery catheter, positioning the delivery catheter with the heart valve prosthesis at a native heart valve, aligning a major axis of the heart valve prosthesis with a major axis of an annulus of the native heart valve, and deploying the heart valve prosthesis at the annulus of the native heart valve. 
     In any of the embodiments, the heart valve prosthesis may be balloon expandable, and the step of loading the substantially elliptically shaped heart valve prosthesis onto the delivery catheter may comprise crimping the substantially elliptically shaped heart valve prosthesis onto an outer surface of a substantially elliptically shaped balloon in an uninflated state, wherein the major axis of the heart valve prosthesis is circumferentially aligned with a major axis of the balloon, and the step of deploying the heart valve prosthesis comprises transitioning the balloon from the uninflated state to an inflated state to transition the heart valve prosthesis from the radially collapsed configuration to the radially expanded configuration. 
     In any of the embodiments, the delivery catheter may include a radiopaque marker aligned with the major axis of the substantially elliptically shaped balloon and the major axis of the substantially elliptically shaped heart valve prosthesis, and the step of aligning the major axis of the heart valve prosthesis with the major axis of the annulus of the native heart valve comprises aligning the radiopaque marker with the major axis of the annulus of the native heart valve. 
     In any of the embodiments, the native heart valve may be a native aortic valve, a native mitral valve, a native pulmonic valve, or a native tricuspid valve. 
     In any of the embodiments, the native heart valve may be a prosthetic aortic valve, a prosthetic mitral valve, a prosthetic pulmonic valve, or a prosthetic tricuspid valve. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  depicts a schematic side view illustration of a heart valve prosthesis in accordance with an embodiment hereof, wherein the heart valve prosthesis is in a radially expanded configuration. 
         FIG. 2  depicts a perspective view illustration of a frame of the heart valve prosthesis of  FIG. 1 , wherein the frame is in a radially expanded configuration. 
         FIG. 3  depicts a top view illustration of the heart valve prosthesis of  FIG. 1 , wherein the heart valve prosthesis is in the radially expanded configuration. 
         FIG. 4  depicts a partial side view illustration of a portion of the frame of the heart valve prosthesis of  FIG. 1 . 
         FIG. 5  depicts a partial side view illustration of an inflow end of the frame of the heart valve prosthesis of  FIG. 1 . 
         FIG. 6  depicts a side view illustration of the frame of the heart valve prosthesis of  FIG. 1  with the frame in a radially collapsed configuration. 
         FIG. 7  depicts a side view illustration of the frame of heart valve prosthesis of  FIG. 1  with the frame in a radially collapsed configuration and laid flat for illustrative purposes. 
         FIG. 8  depicts an end view illustration of the heart valve prosthesis of  FIG. 1  with another embodiment of a leaflet configuration of a prosthetic valve of the heart valve prosthesis. 
         FIG. 9  depicts a side view illustration of a system for delivering, positioning, and deploying a substantially elliptical heart valve prosthesis. 
         FIG. 10  depicts a side view illustration of a distal portion of the system of  FIG. 9 . 
         FIG. 11  depicts a side view illustration of a distal portion of the system of  FIG. 9  with the system rotated as compared to  FIG. 10 . 
         FIG. 12A  depicts a cross-sectional illustration taken along line  12 A- 12 A of  FIG. 9 . 
         FIG. 12B  depicts a cross-sectional view of an alternative embodiment of the delivery catheter of  FIG. 9 . 
         FIG. 12C  depicts a cross-sectional view of the embodiment of  FIG. 12B  at a location within the balloon. 
         FIG. 13  depicts a cross-sectional view illustration of the balloon of the system of  FIG. 9  with the balloon in an inflated state and the heart valve prosthesis removed for clarity. 
         FIG. 14  depicts a cut away view illustration of a native heart with the system of  FIG. 9  being delivered to the site of a native aortic valve. 
         FIG. 15  depicts a cut away view illustration of a native heart with the system of  FIG. 9  delivered to the site of a native aortic valve and rotated as compared to  FIG. 14 . 
         FIG. 16  depicts a cut away view illustration of a native heart with the balloon of the system of  FIG. 9  being inflated to radially expand the heart valve prosthesis. 
         FIG. 17  depicts a cut away view illustration of the heart with the delivery catheter of the system of  FIG. 9  removed after the heart valve prosthesis has been radially expanded at the site of the native aortic valve. 
     
    
    
     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. The terms “distal” and “proximal”, when used in the following description to refer to a delivery system or catheter are with respect to a position or direction relative to the treating clinician. Thus, “distal” and “distally” refer to positions distant from, or in a direction away from the treating clinician, and the terms “proximal” and “proximally” refer to positions near, or in a direction toward the clinician. The terms “distal” and “proximal”, when used in the following description to refer to a device to be implanted into a vessel, such as a heart valve prosthesis, are used with reference to the direction of blood flow. Thus, “distal” and “distally” refer to positions in a downstream direction with respect to the direction of blood flow, and the terms “proximal” and “proximally” refer to positions in an upstream direction with respect to the direction of blood flow. 
     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 an elliptically shaped heart valve prosthesis and systems and methods for deploying an elliptically shaped heart valve prosthesis at the site of a native heart valve, the invention may also be used in other body passageways where it is deemed useful. 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. 
     The present invention in various embodiments relates to an elliptically shaped heart valve prosthesis for replacement of a native heart valve.  FIGS. 1-7  illustrate an elliptically shaped heart valve prosthesis  100  according to an embodiment hereof. As described in more detail below, the heart valve prosthesis is substantially elliptical when viewed in cross-section. The heart valve prosthesis  100  includes a frame  102  supporting a prosthetic valve  104 . The heart valve prosthesis  100  has a radially collapsed configuration for delivery, and a radially expanded configuration when deployed. 
     The frame  102 , as shown in  FIGS. 1 and 2 , also referred to as a stent or support structure, is a structure including a lumen  106  extending from an inflow end  108  to an outflow end  110  of the frame  102 . The frame  102  includes a radially collapsed state for delivery corresponding to the radially collapsed configuration of the heart valve prosthesis  100 , and a radially expanded state when deployed corresponding to the radially expanded configuration of the heart valve prosthesis  100 . The frame  102  is configured to engage tissue at an annulus of the native heart valve when the frame  102  is in the radially expanded state. The frame  102  is further configured to provide a secure mounting surface for the valve component  104 . The frame  102  includes a plurality of struts  114  joined by bent segments or crowns  116  to form a plurality of bands  112 . Each band  112  is coupled to an adjacent band  112  at the adjacent crowns  116  to form the frame  102 . Although described as individual bands  112  connected together, this is not meant to be limiting, and the frame  102  may be formed as a unity, as by laser cutting a tube into the desired pattern. 
     Each strut  114  of the plurality of struts  114  includes a segment stiffness factor k, hereafter referred to as a “stiffness”, as described below. The stiffness of each strut  114  of the plurality of struts  114  is varied such that when the frame  102  is in the radially expanded state, the frame  102  is substantially elliptically shaped when viewed in cross-section perpendicular to a central longitudinal axis LA of the frame  102 . The substantially elliptical frame  102  includes a major axis  118  and a minor axis  120 , with the major axis  118  being longer than the minor axis  120 , as shown in  FIG. 3 . As used herein, the term “substantially elliptical” or “substantially elliptically shaped” means that the structure has an approximately elliptical shape with a major axis and a minor axis substantially perpendicular to the major axis, and that the major axis is greater in length than the minor axis. However, the shape need not be a mathematical ellipse such that oval shaped falls within the scope of “substantially elliptical” or “substantially elliptically shaped”. The term “substantially perpendicular” as used herein with reference to the major axis and the minor axis of an ellipse or elliptical shape, means that the major axis and the minor axis intersect at approximately a 90° angle, plus or minus 10°. 
     Each crown  116  is formed by a pair of struts  114 , as best shown in  FIG. 4 . Each strut  114  includes the stiffness k, which is a measure of the rigidity of the strut  114 , or, in other words, the measure of the ability or inability of the strut  114  to flex. The stiffness of each strut  114  may be expressed by the equation: 
         k=EtW   3 /2 L   3  cos 2 θ
 
     In the equation, E is the elasticity modulus of a substance, t is the thickness of the wall of the segment or strut  114 , W is the width of the segment or strut  114 , L is the length of the segment or strut  114 , and θ is the angle of deployment. The width W is measured from an outer surface of the strut  114  to the opposite outer surface of the strut  114  has shown in  FIG. 4 . With the elasticity modulus E, the wall thickness t, the length L, and the angle of deployment θ held constant for each strut  114 , the stiffness k for each strut  114  may be varied by varying the width W of each strut  114 . In embodiments hereof, the stiffness of the plurality of struts  114  is varied by varying a width W of at least one strut  114  of the plurality of struts  114 . The greater the width W of the strut  114 , the greater the stiffness k and the less flexible the strut  114 . Thus, struts  114  with the greater width W are less flexible than struts  114  with a smaller width W, other factors being equal. As shown in  FIGS. 3-4 , varying the width W of the plurality of struts  114  at the inflow end  108  varies the stiffness k of the plurality of struts  114 . Struts  114  with a greater width W and the corresponding greater stiffness k are less flexible and radially expand less than struts  114  with a smaller width W and a corresponding smaller stiffness k. The varying of the widths W of the plurality of struts  114  of the frame  102  permit the frame  102  to expand to an elliptical shape when expanded to the radially expanded state. 
     In the embodiment shown in  FIGS. 1-7 , the frame  102  includes eighteen (18) crowns  116  at the inflow end  108  and eighteen (18) crowns  116  at the outflow end  110 . Further, as best shown in  FIGS. 3-4 , each strut  114  of the plurality of struts  114  is formed with one (1) of five (5) possible widths, a first width W 1 , a second width W 2 , a third width W 3 , a fifth width W 4 , or fifth width W 5 . In particular,  FIG. 3  shows an embodiment wherein each crown  116  is either a first crown  116   a , a second crown  116   b , a third crown  166   c , a fourth crown  116 , or a fifth crown  116   e .  FIG. 4  shows that each first crown  116   a  is formed between two first struts  114   a , each of which is the first width W 1 . Similarly, each second crown  116   b  is formed between two second struts  114   b , each of which is the second width W 2 ; each third crown  116   c  is formed between two third struts  114   c , each of which is the third width W 3 ; each fourth crown  116   d  is formed between two fourth struts  114   d , each of which is the fourth width W 4 ; and each fifth crown  116   e  is bounded by two fifth struts  114   e , each of which is the fifth width W 5 . The first width W 1  is smaller than the second width W 2 , which is smaller than the third width W 3 , which is smaller than the fourth width W 4 , which is smaller than the fifth width W 5 . In the embodiment of  FIGS. 3-4 , the inflow end  108  of the frame  102  includes two (2) first crowns  116   a , four (4) second crowns  116   b , four (4) third crowns  116   c , four (4) fourth crowns  116   d , and four (4) fifth crowns  116   e.    
     The specific pattern or arrangement of the pairs of struts  114   a - 114   e  and corresponding crowns  116   a - 116   e  permit the frame  102  to expand to a predictable designed elliptical shape. When in the radially expanded state, the frame  102  includes a major axis  118  and a minor axis  120 . The first struts  114   a  with the first widths W 1  (smallest) are disposed adjacent ends of the major axis  118 , and the fifth struts  114   e  with the fifth widths W 5  (largest) are disposed adjacent ends the minor axis  120 , as shown in  FIG. 3 . The difference in the width W of each strut  114 , as well as the arrangement of the struts  114  may be selected to provide a specific ellipticity when the frame  102  is in the radially expanded state. 
     Referring next to  FIG. 5 , which depicts a partial side view of the inflow end  108  of the frame  102 , each crown  116  includes an intrados  140 . Each intrados  140  is the inner curve facing an acute angle I° of each crown  116 . When the frame  102  is in the radially collapsed state, the intrados  140  of each crown  116  is substantially the same. As used herein, the terms “substantially” or “generally” mean approximately, with the intrados  140  of each crown  116  being equal within normal manufacturing tolerances. However, when the frame  102  is expanded, the struts  114  adjacent each crown  116  are moved in opposite directions (i.e., away from each other), as indicated by arrows  130 ,  132 . The crown  116  is thus drawn axially towards a longitudinally middle portion of the frame, as indicated by the arrow  134 , as shown in  FIG. 5 , thereby increasing the angle I°. The width W of each strut  114  adjacent the corresponding crown  116  determines the amount the angle I° of the intrados  140  increases and the axial distance in the direction of the arrow  134  the crown  116  moves during radial expansion of the frame  102 . 
     When the frame  102  is in the radially collapsed state, the plurality of crowns  116  at the inflow end  108  are non-planar, or not aligned in a first plane PL 1 , as shown in  FIG. 6 . In other words, the plurality of crowns  116  at the inflow end  108  are not aligned in a first plane PL 1  perpendicular to a central longitudinal axis LA of the frame  102 . Moreover, as best viewed in  FIG. 7 , the plurality of struts  114  at the inflow end  108  of the frame  102  are of a non-uniform length. More precisely, the crowns  116   a  formed of the struts  114   a  with the first width W 1  have the greatest length L and extend axially the greatest distance from the inflow end  108  in the radially collapsed state. The greater the width W of each strut  114  of the corresponding crown  116 , the shorter the length L of the strut  114  and the less the corresponding crown  116  extends from the end  108  when the frame  102  is in the radially collapsed state. During radial expansion of the frame  102 , the first crowns  116   a  formed between the first struts  114   a  with the first widths W 1  (smallest) move axially in the direction of the arrow  134  the largest distance, as compared to the other crowns  116 . Moreover, the greater the width W of each strut  114  adjacent a corresponding crown  116 , the less distance the corresponding crown  116  moves axially upon expansion. Thus, the crowns  116  at the inflow end  108  of the frame  102  move axially during radial expansion, such that when the frame  102  is in the radially expanded state, the plurality of crowns  116  at the inflow end  108  are substantially planar, or aligned in a second plane PL 2 , as shown in  FIG. 1 . While  FIGS. 1-7  show and describe radial expansion at the inflow end  108  of the frame  102 , this is by way of example and not limitation. It will be understood that the outflow end  110  of the frame  102  is configured similarly and descriptions of the movement of the crowns  116  and the corresponding intradoses  140  apply equally to the crowns  116  and the corresponding intradoses  140  at the outflow end  110 . 
     While described herein with each strut  114  having one (1) of five (5) different strut widths W 1 -W 5 , this is by way of example and not limitation, and in other embodiments the frame  102  may include the plurality of struts  114  with each strut  114  including a width W from a group of more or fewer possible widths. Additionally, while the frame  102  has been described with eighteen (18) crowns  116  at each of the inflow end  108  and the outflow end  110 , this too is by way of example and not limitation. In other embodiments, the frame  102  may include more or fewer crowns  116  at the inflow end  108  and the outflow end  110 . Moreover, while the frame  102  shown in  FIGS. 1-7  has a specific pattern of strut widths W around the frame  102  to elicit a specific ellipticity, the invention is not limited to the pattern shown. The width of each strut  114 , as well as the distribution pattern of the plurality of struts  114  of varying widths W around the frame  102  may be altered to provide a desired ellipticity. For example, the ellipticity of the frame  102  of the heart valve prosthesis  100  may be in a range of 1.0 to 1.8. 
     In the embodiment of  FIGS. 1-7  the heart valve prosthesis  100  is configured as a replacement for a native aortic valve. When configured as a replacement for a native aortic valve, the inflow end  108  of the frame  102  extends into and anchors within the aortic annulus of a patient&#39;s left ventricle and the outflow end  110  of the frame  102  is positioned in the patient&#39;s ascending aorta. 
     As described herein, the heart valve prosthesis  100  is expandable from the radially collapsed configuration to the radially expanded configuration. More precisely, the frame  102  is balloon expandable or mechanically expandable from the radially collapsed state to the radially expanded state. “Balloon expandable” or “mechanically expandable” as used herein means that a structure is plastically deformed such that the structure remains in the radially expanded state after being radially expanded by a suitable balloon or other mechanical expansion device. The frame  102  may be made from materials such as cobalt chromium alloys (e.g. MPN35, L605), platinum iridium, platinum chromium, or stainless steel alloys (e.g. 316L), and other suitable materials known to those skill in the art. 
     Alternatively, in another embodiment, a heart valve prosthesis may be self-expanding. “Self-expanding” as used herein means that a structure has a shape memory to return to the radially expanded configuration. Shape memory may be imparted on the structure that forms the frame using techniques understood in the art. In embodiments wherein the frame is self-expanding, the frame may be retained in a radially collapsed state for delivery by methods and devices understood by persons knowledgeable in the art. For example, and not by way of limitation, the self-expanding elliptical shaped heart valve prosthesis may be retained in the radially collapsed configuration by a suitable sheath or capsule or a cinching mechanism. Suitable cinching mechanisms and assemblies for retaining self-expanding heart valve prostheses are described in U.S. Pat. No. 9,629,718 to Gloss, which is incorporated herein by reference in its entirety. Suitable sheaths/capsules of a delivery catheter are described, for example, in in U.S. Pat. No. 8,926,692, to Dwork, which is incorporated herein by reference in its entirety. 
     As previously described herein, the valve prosthesis  100  includes the prosthetic valve  104  disposed within the lumen  106  of the frame  102 . The prosthetic valve  104  may further include a skirt affixed to the frame  102 . The prosthetic valve  104  is configured as a one-way valve to allow blood flow in one direction and prevent blood flow in the opposite direction. The prosthetic valve  104  blocks flow in one direction to regulate flow via valve leaflets. More particularly, and with reference back to  FIG. 3 , in an embodiment, the prosthetic valve  104  includes four (4) valve leaflets  122 ,  124 ,  126 ,  128 . The valve leaflets  122 ,  124 ,  126 ,  128  form a replacement valve that opens due to a pressure differential such that pressure on the inflow side of the valve leaflets  122 ,  124 ,  126 ,  128  is greater pressure on the outflow side of the valve leaflets  122 ,  124 ,  126 ,  128 . The prosthetic valve  104  closes when pressure on the outflow side of the valve leaflets  122 ,  124 ,  126 ,  128  is greater than on the inflow side. The valve leaflets  122 ,  124 ,  126 ,  128  may be sutured or otherwise securely and sealingly attached to an inner circumference of the frame  102 , as understood by persons knowledgeable in the pertinent art. 
     The valve leaflets  122 ,  124 ,  126 ,  128  of the prosthetic valve  104  may be made of natural pericardial material obtained from, for example, heart valves, aortic roots, aortic walls, aortic leaflets, pericardial tissue, bypass grafts, blood vessels, intestinal submucosal tissue, umbilical tissue and the like from humans or animals, such as tissue from bovine, equine or porcine origins. Alternatively, the valve leaflets of the prosthetic valve  104  may be made of synthetic materials suitable for use as heart valve prosthesis leaflets in embodiments hereof including, but are not limited to polyester, polyurethane, cloth materials, nylon blends, and polymeric materials. 
     While the prosthetic valve  104  is shown with a specific pattern for the leaflets  122 ,  124 ,  126 ,  128 , the invention is not limited to the pattern shown in  FIG. 3 . For example, and not by way of limitation, in an alternative embodiment a prosthetic valve  104 ′ may include leaflets  122 ′,  124 ′,  126 ′,  128 ′ in a pattern as shown in  FIG. 8 . 
     The elliptical valve prosthesis  100  shown and described with respect to  FIGS. 1-7  is shown as a one-piece valve prosthesis in that the frame  102  and prosthetic valve  102  are joined together as a single piece and delivered to the treatment site, and then deployed, as described in more detail below. However, the invention is not limited to such an embodiment. In other embodiments, an elliptical frame as described above may not include a prosthetic valve such that the elliptical frame is deployed to act as an anchor stent. A valve prosthesis as described above may then be delivered and deployed within the already-deployed anchor stent. The valve prosthesis in such an embodiment may or may not be elliptical, as described above. Due to the anchor stent already deployed within the annulus of the native heart valve, the frame of the valve prosthesis may have less outward radial force to maintain its location, because the frame is coupled to the anchor stent. Such an embodiment enables a smaller overall delivery profile because the frame of the valve prosthesis is not required to have as much radial force, and therefore may be thinner such that it can be crimped to a smaller diameter for delivery. 
     An embodiment of a system  301  for percutaneously delivering and deploying a heart valve prosthesis, such as the heart valve prosthesis  100  previously described herein, to a site of a native heart valve, is shown in  FIGS. 9-12 . The system  301  includes a delivery catheter  303  and the heart valve prosthesis  100 . The delivery catheter  303  includes a handle  305 , an outer shaft  307 , an inner shaft  309 , a distal tip  311 , and a balloon  313 . 
     The balloon  313  is coupled to a distal portion of the outer shaft  307  and distal portion of the inner shaft  309 , as described in more detail below. The heart valve prosthesis  100 , as previously described, may be crimped onto the balloon  313  in the radially collapsed configuration onto the balloon  313  for delivery to the native heart valve, and then may be deployed by inflating the balloon  313  to radially expand the valve prosthesis  100  to the radially expanded configuration. The balloon  313  may also be elliptical in cross-section to enable a smooth expansion of the elliptically shaped valve prosthesis  100 . Thus, the major axis  118  of the heart valve prosthesis  100  is circumferentially or rotational aligned with a major axis  339  of the balloon  313 , as shown in  FIG. 12  and described below. 
     The handle  305  provides a surface for convenient handling and grasping by a user. While the handle  305  of  FIG. 9  is shown with a generally cylindrical shape, this is by way of example and not limitation, and other shapes and sizes may be utilized. 
     Also shown in  FIGS. 9-11 , the inner shaft  309  includes a lumen  317  disposed therethrough. The lumen  317  is generally referred to as a guidewire lumen and enables a guidewire to be inserted into a distal port  329  of the lumen  317  such that the delivery catheter  303  may be tracked over the guidewire to the treatment site, as known to those skilled in the art. The inner shaft  309  includes a proximal end  332  couple to the handle  305  and including a proximal port  331  for a guidewire to extend through and into the lumen  317 . The inner shaft also includes a distal end  325  coupled to the distal tip  311  and coupled to the balloon  313 , as described in more detail below. 
     The outer shaft  307  of the delivery catheter  303  also includes a lumen  315  extending therethrough. The lumen  315  forms an annular inflation lumen between an outer surface of the inner shaft  309  and the inner surface of the outer shaft  307 . At least a portion of the outer shaft  307  is configured for fixed connection to the handle  305 . In an embodiment, a proximal end  319  of the outer shaft  307  may extend through and is coupled to the handle  305 . As distal end  321  of the outer shaft is coupled to the balloon, as explained in more detail below. 
     Although the outer shaft  307  and the inner shaft  309  are described herein as each being a single component, this is by way of example and not limitation, and the shafts  307 ,  309  may each include multiple components such as, but not limited to proximal and distal shafts or other components suitable for the purposes described herein. The outer and inner shafts  307 ,  309  may be formed of materials such as but not limited to polyurethane (e.g. Peliethane©, Elasthane™, Texin®, Tecothane®), polyamide polyether block copolymer (e.g. Pebax®, nylon 12), polyethylene, or other suitable materials 
     Further, although the outer shaft  307  and the inner shaft  309  are described herein as two shafts in a co-axial arrangement, as shown in  FIG. 12A , this is not meant to be limiting. For example, and not by way of limitation, there may be a single shaft  307 ′ including both an inflation lumen  315 ′ and a guidewire lumen  317 ′, as known to those skilled in the art, and as shown in  FIG. 12B . 
     As shown in  FIGS. 9-11 , a proximal neck  323  of the balloon  313  is attached to a distal end  321  the outer shaft  307 . The outer shaft  307  terminates within an interior of the balloon  313  such that inflation fluid injected through the inflation lumen  315  exits the inflation lumen  315  within the interior of the balloon  313  to inflate the balloon  313 . A distal neck  327  of the balloon  313  is attached to a distal end  325  of the inner shaft  309 . The proximal and distal attachments of the balloon  313  to the outer and inner shafts  307 ,  309 , respectively, may be via adhesives, fusion, mechanical attachment, or other methods known to those skilled in the art. Alternatively, in the embodiment shown in  FIG. 12B , both the proximal neck  323  and the distal neck  327  of the balloon  313  are attached to the single shaft  307 ′, and the inflation lumen  315 ′ includes a port  351 ′ exiting the shaft  307 ′ between the proximal neck  323  and the distal neck  327  to inflate the balloon  313 , as known to those skilled in the art, and shown in  FIG. 12C . 
     As shown in  FIGS. 9-11 , the distal tip  311  includes a lumen  335  extending therethrough. The lumen  335  is sized to receive the distal end of the inner shaft  309  and provide a continuous lumen with lumen  317  of the inner shaft  309 . The distal tip  311  may be coupled to the inner shaft  309  by methods such as, but not limited to adhesives, bonding, welding, fusing, mechanical connection, or other suitable coupling methods. 
     When the interior of the balloon  313  is filled with an inflation fluid, the balloon  313  inflates to an inflated or radially expanded state. As shown in  FIG. 13 , the inflated balloon  313  is substantially elliptically shaped in cross-section transverse to the central longitudinal axis of the balloon  313 . Thus, the inflated balloon  313 , in cross-section, includes a major axis  339  and a minor axis  341 , as shown in  FIG. 13 . The major axis  339  is longer than the minor axis  341 . In  FIG. 13 , the heart valve prosthesis  100  has been omitted for clarity. The balloon  313  is configured to transition from the uninflated state to the inflated state to radially expand the heart valve prosthesis  100  from the radially compressed configuration to the elliptically shaped radially expanded configuration at the site of a native heart valve. Accordingly, the elliptical shape of the balloon  313  in the inflated state corresponds to the elliptical shape of the heart valve prosthesis  100  in the radially expanded configuration. While the balloon  313  is shown with a specific ellipticity, it will be understood that this is by way of example and not limitation, and that alternative ellipticities may be utilized. For example, the ellipticity of the balloon  313  may be in a range of 1.0 to 1.8. The balloon  313  may be a standard construction noncompliant or semi-compliant balloon constructed of materials such as, but not limited to polyethylene terephthalate (PET), nylon, or polyurethane. 
     In an embodiment, the delivery catheter  303  includes a radiopaque marker  343 , as shown in  FIG. 9-11 . In the embodiment shown in  FIGS. 9-11 , the marker  343  is attached to or part of the inner shaft  309  adjacent the distal end  325  of the inner shaft  309 . However, this is not meant to be limiting, and the marker  343  may be attached to or part of the outer shaft  307  adjacent the distal end thereof, or adjacent a distal end of the shaft  307 ′ in the embodiment of  FIGS. 12B-12C . In an embodiment, the marker  343  includes a head  345  and a tail  347  extending substantially perpendicular to the head  345 . The tail  347  of the marker  343  is circumferentially aligned with one of the axes  339 ,  341  of the balloon  313 . For example, the tail  347  may be circumferentially aligned with the major axis  339  of the balloon  313 . Further, the heart valve prosthesis  100  is crimped onto the balloon  313  such that the major axis  118  of the frame  102  is aligned with the major axis  339  of the balloon  313 , and hence is aligned with the tail  347  of the marker  343 . Thus, when delivered to the treatment site, the treating clinician can align the tail  347  of the marker  343  with the larger axis of the annulus of the native heart valve such that the major axes  118 ,  339  of the heart valve prosthesis  100  and the balloon  313 , respectively, are aligned with the larger axis of the annulus. As can be seen by comparing  FIGS. 10 and 11 , when viewing the delivery catheter  303 , the treating clinician can determine if the major axes  118 ,  339  are in line with the view provided, as shown in  FIG. 10 , or are not aligned with the view, as shown in  FIG. 11 , which shows the major axes  118 ,  229  rotated by approximately 90 degrees. 
     The marker  343  may be formed of materials such as, but not limited to, platinum, gold, platinum iridium, or any other suitable material. The marker  343  may be coupled to the inner shaft  309 , the outer shaft  307 , or the shaft  307 ′ by methods such as, but not limited to adhesives, bonding, welding, fusing, mechanical connection, or other suitable coupling methods, or may be formed as part of the shaft. The term “radiopaque” refers to the ability of a substance to absorb X-rays. Few substances will transmit 100% of X-rays and few substances will absorb 100% of X-rays. For the purposes of this disclosure, “radiopaque” will refer to those substances or materials which have suitable visibility for heart valve procedures when being imaged by an X-ray imaging device such as but not limited to a fluoroscope. 
     Although the marker  343  is shown with a head  345  and a tail  347 , this is not meant to be limiting, and other designs may be used such that a treating clinician is able to align the marker with a larger or smaller axis of the annulus AN of the native heart valve AV, as explained in more detail below. 
       FIGS. 14-17  are sectional cut-away views of a heart HE illustrating a method for delivery, positioning, and deploying the heart valve prosthesis  100  using the system  301  of  FIG. 9  in accordance with an embodiment hereof. With reference to  FIG. 14 , the system  301  is shown having been introduced into the vasculature via a percutaneous entry point, e.g., via the Seldinger technique, and tracked through the vasculature and into the aorta AO until the heart valve prosthesis  100  is in proximity to and/or apposition with an annulus AN of the native aortic valve AV. Intravascular access to the aorta AO may be achieved via a percutaneous access site to femoral artery access up to the aorta AO, or other known access routes. Thereafter, a guidewire GW is advanced through the circulatory system, eventually arriving at the heart HE. Once the guidewire GW is positioned, a guide catheter GC is advanced through the vasculature and positioned proximate or downstream to the native aortic valve AV. The proximal end of the guidewire may then be loaded into the port  329  at the distal end of the delivery catheter  303 , and the delivery catheter may be advanced to the treatment site over the guidewire. Although described herein as a transfemoral approach for percutaneously accessing the native aortic valve AV, the heart valve prosthesis  100  may be positioned within the desired area of the heart HE via other methods. In addition, although described with the use of the guide catheter GC and the guidewire GW, in another embodiment hereof the delivery catheter  303  may access the aorta AO without the use of the guidewire GW and/or the guide catheter GC. 
     With reference back to  FIG. 14 , it will be understood that the system  301  is assembled with the heart valve prosthesis  100  loaded onto the delivery catheter  303  with the heart valve prosthesis  100  in the radially collapsed configuration and disposed about the outer surface of the balloon  313  in the uninflated state, with the major axis  118  of the frame  102  of the heart valve prosthesis  100  circumferentially aligned with the tail  347  of the marker  343 . With the system  301  so assembled, the system  301  is advanced to the site of the native aortic valve AV until the heart valve prosthesis  100  is positioned within the annulus AN of the native aortic valve AV. 
     As can be seen in  FIG. 14 , the marker  343  on the delivery catheter  303  is seen on the left side of the inner shaft  309 . Thus, the major axes  118 ,  339  of the frame  102  and balloon  313 , respectively, are rotated 90 degrees with respect to the view of  FIG. 14 . In other words, the major axes  118 ,  330  are aligned left-right in the view of  FIG. 14 . If the view of  FIG. 14  is such that the major axis of the annulus AN of the native aortic valve is left-right, then no further action is necessary. If however, the larger axis of the annulus AN is front-back in the view of  FIG. 14 , then the major axes  118 ,  339  of the frame  102  and balloon  303  are not aligned with the major axis of the annulus AN. In such a situation, as shown in  FIG. 15 , the handle  305  (not visible in  FIGS. 14-17 ) may be rotated (in this example, counter-clockwise in a direction of the arrow  358 ) to align the tail  347  of the marker  343  with the major axis of the annulus AN of the native aortic valve AV. Radial alignment of the major axis  118  of the frame  102  of the heart valve prosthesis  100  and the major axis of the annulus AN of the heart HE insures optimal sealing of the elliptically shaped heart valve prosthesis  100  with the elliptically shaped annulus AN to prevent paravalvular leakage (PVL) when the heart valve prosthesis  100  is deployed therein. Those skilled in the art would understand that instead of the tail  347  of the marker  343  being aligned with the major axes  118 ,  339  of the frame  102  and the balloon  339 , in other embodiments, the tail  347  of the marker  343  may be aligned with the minor axes  120 ,  341  of the frame  102  and the balloon  339  such that the treating clinician may align the tail  347  with the minor axis of the annulus AN. Depending on the view of the fluoroscope used, it may be desirable such that when the delivery catheter  303  is properly aligned, the tail  347  is visible at the “front” of the catheter  303 , in  FIG. 15 . 
     When the heart valve prosthesis  100  is properly aligned with and positioned within the annulus AN of the native aortic valve AV, and the clinician is ready to deploy the heart valve prosthesis  100 , inflation fluid under pressure is pumped into the inflation lumen  315  through an inflation port  353  ( FIG. 9 ) such that the inflation fluid exits a distal opening of the outer shaft  307  and the balloon  313  to inflate the balloon  313 , as shown in  FIG. 16 . As the balloon  313  transitions from the uninflated state to the inflated state, the balloon  313  radially expands the heart valve prosthesis  100  disposed thereon from the radially collapsed configuration to the elliptically shaped radially expanded configuration. The heart valve prosthesis  100  plastically deforms to the radially expanded configuration and engages the tissue at the annulus AN of the native aortic valve AV. Alignment of the major axis  339  of the balloon  313  and the co-aligned major axis  118  of the frame  102  of the heart valve prosthesis  100  with the major axis of the annulus AN of the native aortic valve AV in the previous step insures that the heart valve prosthesis  100  fully expands and sealingly conforms to the substantially elliptical shape of the annulus AN of the native aortic valve AV. 
     Following the successful positioning and deployment of the heart valve prosthesis  100  within the annulus AN of the native aortic valve AV, pressure on the inflation fluid is released and the inflation fluid flows out of the balloon  313  and through the inflation lumen  315  such that the balloon  313  transitions from the inflated state to the uninflated state. Once the balloon  313  is in the uninflated state, the delivery catheter  303 , the guide catheter GC, and the guidewire GW can be removed using established procedures. With the delivery catheter  303  removed, the heart valve prosthesis  100  remains at the annulus AN of the native aortic valve AV, as shown in  FIG. 17 . 
     Imaged guidance, e.g., intracardiac echocardiography (ICE), fluoroscopy, computed tomography (CT), intravascular ultrasound (IVUS), optical coherence tomography (OCT), or other suitable guidance modality, or combination thereof, may be used to aid the clinician&#39;s delivery positioning, and radial alignment of the heart valve prosthesis  100 . 
     While the method of  FIGS. 14-17  is described with the heart valve prosthesis  100  of  FIGS. 1-7  and the system  301  of  FIGS. 9-13 , this is not meant to be limiting. It will be understood that other embodiments of substantially elliptically shaped heart valve prostheses may be utilized with a similar method. 
     Although the method has been described with respect to the delivery, positioning, radial alignment, and deployment of a heart valve prosthesis at the site of a native aortic valve, the method may be utilized at other locations. 
     While only some embodiments according to the present invention have been described herein, it should be understood that they have been presented by way of illustration and example only, and not limitation. Various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Further, 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.