Abstract:
A heart valve prosthesis and delivery systems are provided for replacing a cardiac valve. The heart valve prosthesis includes a self-expanding frame includes a portion having a crimp that provides additional flexibility to the self-expanding frame in the collapsed configuration.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of U.S. application Ser. No. 13/658,044, filed Oct. 23, 2012, now U.S. Pat. No. 9,226,823, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is related to a heart valve frame. More specifically, the present invention is directed to a valve prosthesis. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cardiac valves exhibit two types of pathologies: regurgitation and stenosis. Regurgitation is the more common of the two defects. Either defect can be treated by a surgical repair. Under certain conditions, however, the cardiac valve must be replaced. Standard approaches to valve replacement require cutting open the patient&#39;s chest and heart to access the native valve. Such procedures are traumatic to the patient, require a long recovery time, and can result in life threatening complications. Therefore, many patients requiring cardiac valve replacement are deemed to pose too high a risk for open heart surgery due to age, health, or a variety of other factors. These patient risks associated with heart valve replacement are lessened by the emerging techniques for minimally invasive valve repair, but still many of those techniques require arresting the heart and passing the blood through a heart-lung machine. 
         [0004]    Efforts have been focused on percutaneous transluminal delivery of replacement cardiac valves to solve the problems presented by traditional open heart surgery and minimally-invasive surgical methods. In such methods, a valve prosthesis is compacted for delivery in a catheter and then advanced, for example, through an opening in the femoral artery and through the descending aorta to the heart, where the prosthesis is then deployed in the aortic valve annulus. 
         [0005]    During delivery, the delivery system including the valve prosthesis must be advanced through multiple bends in the patient&#39;s vasculature. Some vascular bends will straighten as the relatively stiff delivery system is passed through. However other vascular bends, e.g. the aortic arch, cannot be straightened. Therefore, a typical delivery system bends in a single plane and kinks, or folds onto itself, when advanced through a substantial vascular bend in order to traverse the bend. This bending of the delivery system is presently routine during delivery of the valve prosthesis frame. Bending of the delivery system allows for a longer valve prosthesis frame that can be anchored in the aortic annulus and the ascending aorta. 
         [0006]    A typical valve prosthesis frame is made of self-expanding metals, such as Nitinol. The metal structure of the nitinol holds the compressed frame into a tubular structure which resists bending and kinking. Thus, bending, flexing, and/or kinking the valve prosthesis and delivery system during tracking and delivery typically requires a large amount of bending force. 
         [0007]    In view of the foregoing, it would be desirable to provide a valve prosthesis that is capable of conforming to a patient&#39;s anatomy while providing a uniform degree of rigidity and protection for critical valve components. Protection for critical valve components is essential to maintain reliability for the valve prosthesis. In addition, it would be desirable to provide a delivery system that facilitates bending of the delivery system around a bend and a valve prosthesis that includes a flexible region that is present when the valve prosthesis is compacted for delivery. 
       BRIEF SUMMARY 
       [0008]    Provided herein are valve prostheses that generally include a self-expanding frame, where the valve prosthesis is sutured to the self-expanding frame. Such configurations achieve numerous goals. For example, such configurations can: prevent the native leaflets from obstructing flow through the left ventricular outflow tract (LVOT); prevent the native leaflets from interacting with the prosthetic leaflets; recruit the native leaflets in minimizing perivalvular leaks; maintain proper alignment of the valve prosthesis; avoid systolic anterior mobility; and maintain valve stability by preventing migration of the valve into the atrium or ventricle. 
         [0009]    In view thereof, disclosed herein are aspects of a valve prosthesis which is generally designed to include a frame including a first section having a radially repeating cell pattern and a localized concave depression in a portion of the first section, a second section having a radially repeating cell pattern, and a valve body including a plurality of leaflets attached to the frame in the second section. 
         [0010]    In another exemplary embodiment, disclosed herein are aspects of a method of forming a valve prosthesis frame which generally includes providing a heat set mandrel having a circumferential concave portion corresponding to a first section of the valve prosthesis frame, placing the valve prosthesis frame on the heat set mandrel, providing a compression sleeve around the valve prosthesis frame to form a portion of the first section to the circumferential concave portion of the heat set mandrel while a second portion of the first section remains undeformed, and heat treating the valve prosthesis frame to permanently deform the portion of the first section into a localized concave portion. 
         [0011]    In another exemplary embodiment, disclosed herein are aspects of a method of treating a valve disorder in a patient&#39;s heart which generally includes collapsing a valve prosthesis including a frame having a first section and a second section onto a delivery system, the first section having a localized concave portion and a non-concave portion circumferentially spaced on an axial location of the first section, delivering the delivery system and the valve prosthesis to a heart, expanding the valve prosthesis in the heart, and withdrawing the delivery system from the heart. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         [0012]    The accompanying figures, which are incorporated herein, form part of the specification and illustrate embodiments of a valve prosthesis frame and delivery system. Together with the description, the figures further serve to explain the principles of and to enable a person skilled in the relevant art(s) to make, use, and implant the valve prosthesis described herein. In the drawings, like reference numbers indicate identical or functionally similar elements. 
           [0013]      FIG. 1  is a side view of a valve prosthesis frame according to an aspect of this disclosure. 
           [0014]      FIG. 2  is a front view of the valve prosthesis frame shown in  FIG. 1  rotated 90 degrees therefrom according to an aspect of this disclosure. 
           [0015]      FIG. 3  is a close up side view of a valve prosthesis frame according to an aspect of this disclosure. 
           [0016]      FIG. 4  is a front view of a valve prosthesis according to an aspect of this disclosure. 
           [0017]      FIG. 5  is a side view of a valve prosthesis frame in a collapsed configuration attached to a delivery system according to an aspect of this disclosure. 
           [0018]      FIG. 6  is a front view of the valve prosthesis frame shown in  FIG. 5  rotated 90 degrees therefrom, the valve prosthesis frame being shown in a collapsed configuration attached to a delivery system according to an aspect of this disclosure. 
           [0019]      FIG. 7  is a side view of a valve prosthesis frame in a collapsed configuration attached to a delivery system according to an aspect of this disclosure. 
           [0020]      FIG. 8  is a front view of a heat set mandrel. 
           [0021]      FIG. 9  is a front view of a crimped frame mandrel according to an aspect of this disclosure. 
           [0022]      FIG. 10  is a perspective view of a crimped frame mandrel and compression sleeve according to an aspect of this disclosure. 
           [0023]      FIG. 11  is a top view of a crimped frame mandrel and compression sleeve according to an aspect of this disclosure. 
           [0024]      FIG. 12  is a side view of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0025]      FIG. 13  is a top view of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0026]      FIG. 14  is a sectional view of a portion of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0027]      FIG. 15  is a sectional view of a portion of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0028]      FIG. 16  is a side view of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0029]      FIG. 17  is a sectional view of a portion of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0030]      FIG. 18  is a sectional view of a portion of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0031]      FIG. 19  is a schematic view of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0032]      FIG. 20  is a schematic view of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0033]      FIG. 21  is a schematic view of a valve prosthesis delivery system according to an aspect of this disclosure. 
           [0034]      FIG. 22  is a schematic view of a valve prosthesis delivery system according to an aspect of this disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    The following detailed description of a valve prosthesis frame and delivery system refers to the accompanying figures that illustrate exemplary embodiments. Other embodiments are possible. Modifications can be made to the embodiments described herein without departing from the spirit and scope of the present invention. Therefore, the following detailed description is not meant to be limiting. 
         [0036]    The present invention is directed to a heart valve prosthesis having a self-expanding frame that supports a valve body. The valve prosthesis can be delivered percutaneously to the heart to replace the function of a native valve. For example, the valve prosthesis can replace a bicuspid or a tricuspid valve such as the aortic, mitral, pulmonary, or tricuspid heart valve. 
         [0037]    In one aspect of the invention, the valve body comprises three leaflets that are fastened together at enlarged lateral end regions to form commissural joints, with the unattached edges forming the coaptation edges of the valve. The leaflets can be fastened to a skirt, which in turn can be attached to the frame. The upper ends of the commissure points define an outflow or proximal portion of the valve prosthesis. The opposite end of the valve at the skirt defines an inflow or distal portion of the valve prosthesis. The enlarged lateral end regions of the leaflets permit the material to be folded over to enhance durability of the valve and reduce stress concentration points that could lead to fatigue or tearing of the leaflets. The commissural joints are attached above the plane of the coaptation edges of the valve body to minimize the contacted delivery profile of the valve prosthesis. The base of the valve leaflets is where the leaflet edges attach to the skirt and the valve frame. 
         [0038]    Referring now to  FIGS. 1-4 , frame  100  is an exemplary aspect of the present invention. Frame  100  includes an inflow section  102 , a valve section  104 , and an outflow section  106 . Frame  100  also includes a plurality of cells  130  in the respective sections that can be different sizes and/or shapes. Frame  100  can also include delivery system attachments  120  to connect frame  100  onto a delivery system in a collapsed configuration for delivery into a patient&#39;s vasculature. Valve  200  is connected to frame  100  to form valve prosthesis  10 . Valve  200  includes leaflets  210 , commissures  220 , and a skirt  230 . In one aspect of the invention, valve  200  is connected to frame  100  in inflow section  102  and valve section  104 . The object of the present valve prosthesis is to mimic the native valve structure. 
         [0039]    Frame  100  has a total height of approximately 30 mm to approximately 60 mm. In the expanded configuration, the maximum diameter of inflow section  102  can range from about 16 mm to about 36 mm, with a preferred range of about 21 mm to about 33 mm. Inflow section  102  also has a height of approximately 7 mm to approximately 14 mm. The diameter of valve section  104  can range from about 18 mm to about 26 mm, with a preferred range of about 20 mm to about 24 mm. Valve section  104  also has a height of approximately 7 mm to approximately 14 mm. The maximum diameter of outflow section  106  can range from about 28 mm to about 45 mm, with a preferred range of about 30 mm to about 38 mm. Outflow section  106  also has a height of approximately 10 mm to approximately 25 mm. 
         [0040]    The plurality of cells  130  forming a cell pattern in frame  100  permit frame  100  to adapt to the specific anatomy of the patient, thereby reducing the risk of valve prosthesis migration and reducing the risk of perivalvular leakage. In one aspect of the invention, inflow section  102  of valve prosthesis  10  is disposed in the aortic annulus of the patient&#39;s left ventricle. 
         [0041]    Typically, heart valve prostheses aim to create laminar blood flow through the prosthesis in order to prevent lysis of red blood cells, stenosis of the prosthesis, and other thromboembolic complications. Outflow section  106  is designed to conform to a patient&#39;s anatomy and to anchor valve prosthesis  10  in the patient&#39;s ascending aorta to prevent lateral movement or migration of valve prosthesis  10  due to normal movement of the heart. 
         [0042]    In one aspect of the invention, frame  100  includes a crimp, dent, and/or concave depression  110  in a portion of frame  100 . The term crimp will be used throughout to refer to the crimp, dent, or concave depression  110 . Crimp  110  is provided so that when frame  100  is collapsed onto a delivery system, the region of frame  100  at crimp  110  is flexible around an axis perpendicular to the longitudinal direction. This flexibility permits the frame and delivery system to bend, flex, and/or kink as the frame and delivery system are advanced through a bend in a patient&#39;s vasculature. In one aspect of the invention, crimp  110  extends circumferentially across approximately three cells  130  of frame  100 . In an alternate aspect of the invention, crimp  110  extends circumferentially across approximately one cell  130  of frame  100  to approximately four cells  130  of frame  100 . 
         [0043]    The outer diameter of frame  100  is reduced through crimp  110 , as shown in  FIGS. 1, 3, and 5-6 . More particularly, a reduction in the outer diameter of frame  100  due to crimps or localized concave depressions  110  may be understood: by comparing an outer diameter OD E1  of expanded frame  100  through crimps  110  in  FIG. 1  with an outer diameter OD E2  of expanded frame  100  through adjacent segments without crimps in  FIG. 2 , wherein the adjacent segments are the uncrimped or non-concave portions that circumferentially extend between crimps  110 ; and by comparing an outer diameter OD C1  of collapsed frame  100  through crimps  110  in  FIG. 5  with an outer diameter OD C2  of collapsed frame  100  through adjacent segments without crimps in  FIG. 6 , wherein the adjacent segments are the uncrimped or non-concave portions that circumferentially extend between crimps  110 . In one aspect of the invention, each crimp  110  reduces the outer diameter OD E1 , OD C1  of frame  100  by approximately 1 mm to approximately 3 mm as compared to an outer diameter of a portion of frame  100  that does not include a crimp  110 . In one aspect of the invention, each crimp  110  reduces the outer diameter of frame  100  by approximately 1 mm. In an alternate aspect of the invention, each crimp  110  reduces the outer diameter of frame  100  by approximately 2 mm. In an alternate aspect of the invention, each crimp  110  reduces the outer diameter of frame  100  by approximately 3 mm. 
         [0044]    In the expanded configuration, crimp  110  can be difficult to visually notice because the reduction of the outer diameter of frame  100  due to crimp  110  is relatively small compared to the outer diameter of frame  100  in the expanded configuration. Therefore, crimp  110  will not affect the function or placement of valve prosthesis  10  in the patient&#39;s anatomy. 
         [0045]    However, in the collapsed configuration, shown in  FIGS. 5-6 , the approximately 1 mm to approximately 3 mm crimp is reduced in diameter while the overall diameter of the frame is reduced to a diameter of approximately 6 mm, or to the size of the inner diameter of the delivery system capsule containing the crimped frame and valve, as shown in  FIGS. 5 and 6 . Crimp  110  reduces the outer diameter of a portion of frame  100  and in the collapsed configuration, positions the crimped frame portion towards the center of frame  100 . In other words, crimp  110  pulls frame  100  material in towards the center of frame  100 , closer to the neutral axis of bending. Thus, crimp  110  creates a flexible portion in frame  100  in the collapsed configuration, thus allowing the delivery system and frame to bend, flex, and/or kink in a single plane and traverse a bend in a patient&#39;s vasculature during delivery of valve prosthesis  10 . 
         [0046]    As shown in  FIGS. 1-3 , crimp  110  can be positioned in outflow portion  106  of frame  100 . In an alternate aspect of the invention, crimp  110  can be positioned in any portion of frame  100  to create flexibility at that specific longitudinal location of frame  100 . In one aspect of the invention, crimp  110  can be circumferentially spaced approximately 90 degrees from delivery system attachments  120 . 
         [0047]    In an aspect of the invention, frame  100  can include two crimps  110 , as shown in  FIG. 1 . In this aspect, crimps  110  are circumferentially spaced approximately 180 degrees apart. As such, crimps  110  will facilitate bending, flexing, and/or kinking in a single plane during delivery. 
         [0048]    In an alternate aspect of the invention, frame  100  can include three or more crimps  110 . In a further aspect of the invention, a plurality of crimps  110  can extend along the circumference of frame  100 . In this aspect, crimps  110  create an hourglass shape in frame  100 . The hourglass shape allows frame  100  to bend, flex, and/or kink in multiple planes during delivery of valve prosthesis  10 . In the aspects of the invention including two crimps  110  circumferentially spaced approximately 180 degrees apart and/or a plurality of crimps  110 , each crimp  110  reduces the outer diameter of its respective portion of frame  100  in the expanded configuration and in the collapsed configuration, as depicted by expanded outer diameter OD E1  through opposing crimps  110  in  FIG. 1  and as depicted by collapsed outer diameter OD C1  through opposing crimps  110  in  FIG. 5 . 
         [0049]    In one aspect of the invention, crimp  110  is permanently heat set into frame  100 . In an alternate aspect of the invention, crimp  110  is bi-stable such that crimp  110  is present in the collapsed configuration of frame  100 , but is not present in the expanded configuration of frame  100 . 
         [0050]    As shown in  FIGS. 5-7 , frame  100  can be collapsed onto a delivery system  300  including a pusher tube  310  and a central tube  330 , each of which are concentrically aligned and permit relative motion with respect to each other. At a distal end of pusher tube  310  is a capsule  320  that surrounds the collapsed valve prosthesis  10  during delivery to the implantation site. The capsule  320  restrains valve prosthesis  10  in the radial direction. During deployment, the capsule is withdrawn over the valve prosthesis. 
         [0051]    At a distal end of central tube  330  is a plunger assembly  332  which includes a hub  334 , a tip  338 , and attachment tabs  336 . Tip  338  facilitates the advancement of delivery system  300  through the patient&#39;s vasculature. Hub  334  includes one or more attachment tabs  336  for retaining valve prosthesis  10  on plunger assembly  332 . Tabs  336  also prevent the pre-release of valve prosthesis  10  and assist in retaining valve prosthesis  10  during recapture. 
         [0052]    In the collapsed configuration, frame  100  attachments  120  connect onto attachment tabs  336  on delivery system  300 . Collapsed frame  100  abuts the interior surface of capsule  320  and is thus maintained in a collapsed configuration on delivery system  300 . As shown, crimp  110  facilitates bending, flexing, and/or kinking of frame  100  around axis  400 . 
         [0053]    Manufacture of frame  100  will now be described. Frame  100  can be laser cut from a solid tube of a self-expanding metal, such as Nitinol, with a thin wall thickness. The laser cuts cells  130  into the nitinol tube forming a cell pattern. After laser cutting is complete, the nitinol tube is expanded to increase the overall size and diameter of the nitinol tube. Nitinol is formable when it is brought to a cold temperature. Therefore, to expand the nitinol tube, the nitinol tube is brought to a cold temperature and a cylindrical expansion mandrel is inserted into the formable nitinol tube. The expanded nitinol tube is then subject to a high temperature greater than 500 degrees centigrade. This high temperature cycle removes the stress and strain in the nitinol tube and effectively creates a new natural state for the expanded nitinol tube. This expansion cycle is repeated several times with larger expansion mandrels, each expansion step being within the strain limits of the nitinol material. For the final expansion step, a shaped mandrel is inserted into the expanded nitinol tube. A typical shaped mandrel  410  is shown in  FIG. 8 . Shaped mandrel  410  has the shape of a finished frame. Referring now to  FIGS. 9-11 , mandrel  420  has a concave section machined into it to allow for creation of crimp  110 . Mandrel  420  is inserted into frame  100  and compression sleeve  430  is placed around the concave section on mandrel  420 . Compression spacers  440  are inserted in between compression sleeve  430  and frame  100  to force a portion of frame  100  into the concave section of mandrel  420 . After a final high temperature cycle, frame  100  maintains the shape of mandrel  420  including crimp  110  formed by the concave section of mandrel  420  and compression spacers  440 . Frame  100  then undergoes finishing processing and a valve  200  is sewn to frame  100 . 
         [0054]      FIGS. 12-15  illustrate an alternate delivery system design directed to facilitate bending, flexing, and/or kinking as the frame and delivery system are advanced through a bend in a patient&#39;s vasculature. Delivery system  1300  includes a capsule  1320  having a first portion  1322  having a circular cross-section and a second portion  1324  having an oval cross-section. In one aspect of the invention, delivery system  1300  can be used with a frame that does not include a crimp. Instead of a crimp, the oval cross-section in second portion  1324  brings frame material closer towards the center of the frame and thus creates a flexible region in the frame. In other words, the oval cross section pulls frame material in towards the center of the frame, closer to the neutral axis of bending. Thus, the oval cross-section in second portion  1324  creates a flexible portion in the frame in the collapsed configuration, thus allowing the delivery system and frame to bend, flex, and/or kink in a single plane and traverse a bend in a patient&#39;s vasculature during delivery of valve prosthesis  10 . 
         [0055]      FIGS. 16-18  illustrate an alternate delivery system design directed to facilitate bending, flexing, and/or kinking as the frame and delivery system are advanced through a bend in a patient&#39;s vasculature. Delivery system  2300  includes a capsule  2320  having a first portion  2322  having an inner diameter with a circular cross-section and a second portion  2324  having an inner diameter with an oval cross-section. The outer diameter of first portion  2322  is equal to the outer diameter of second portion  2324 . In one aspect of the invention, delivery system  2300  can be used with a frame that does not include a crimp. Instead of a crimp, the oval cross-section in the inner diameter of second portion  2324  brings frame material closer towards the center of the frame and thus creates a flexible region in the frame. In other words, the oval cross section pulls frame material in towards the center of the frame, closer to the neutral axis of bending. Thus, the oval cross-section in the inner diameter of second portion  2324  creates a flexible portion in the frame in the collapsed configuration, thus allowing the delivery system and frame to bend, flex, and/or kink in a single plane and traverse a bend in a patient&#39;s vasculature during delivery of valve prosthesis  10 . 
         [0056]      FIGS. 19-22  illustrate an alternate delivery system design directed to facilitate bending, flexing, and/or kinking as the frame and delivery system are advanced through a bend in a patient&#39;s vasculature. Delivery system  3300  includes a capsule  3320  attached to the distal end of pusher tube  3310 . Hub  3506  is attached to a distal end of central tube  3330  and is attached to spacer tethers  3504  which are in turn attached to spacers  3502 . In one aspect of the invention, frame  3100  does not include a crimp. Spacers  3502  are placed on opposite sides of frame  3100  in the collapsed configuration. Thus, instead of a crimp, delivery system  3300  uses spacers  3502  to bring frame material closer towards the center of frame  3100  and thus create a flexible region in frame  3100 . In other words, spacers  3502  pull frame material  3100  in towards the center of frame  3100 , closer to the neutral axis of bending. Thus, spacers  3502  create a flexible portion in the frame in the collapsed configuration, thus allowing the delivery system and frame to bend, flex, and/or kink in a single plane and traverse a bend in a patient&#39;s vasculature during delivery of valve prosthesis  10 . 
         [0057]    During deployment of valve prosthesis  3100 , capsule  3320  is withdrawn proximally over frame  3100 , spacers  3502 , and central tube  3330 . Spacers  3502  are not attached to capsule  3320 . Therefore the shape of frame  3100  including the flexible region imparted by spacers  3502  does not change during capsule  3320  withdrawal. As shown in  FIGS. 21-22 , after frame  3100  is fully deployed, spacer tethers  3504  allow spacers  3502  to be retracted back into capsule  3320 . 
         [0058]    The valve prosthesis can replace the function of a tricuspid or bicuspid heart valve including the mitrel valve, the aortic valve, the pulmonary valve, or the tricuspid valve. The valve can be delivered, for example, transfemorally, transeptally, transapically, transradially, or transatrially. 
         [0059]    Implantation of the valve prosthesis will now be described. As discussed above, the valve prosthesis preferably comprises a self-expanding frame that can be compressed to a contracted delivery configuration onto an inner member of a delivery catheter. This frame design requires a loading system to crimp valve prosthesis  10  to the delivery size, while allowing the proximal end of valve prosthesis  10  to protrude from the loading system so that the proximal end can be attached to tabs  336 . 
         [0060]    The valve prosthesis and inner member can then be loaded into a delivery sheath of conventional design. The delivery catheter and valve prosthesis can then be advanced in a retrograde manner through the femoral artery and into the patient&#39;s descending aorta. The catheter then is advanced, under fluoroscopic guidance, over the aortic arch, through the ascending aorta and mid-way across the defective aortic valve. Once positioning of the catheter is confirmed, capsule  320  can be withdrawn proximally, thereby permitting valve prosthesis  10  to self-expand. 
         [0061]    As the valve prosthesis expands, it traps the leaflets of the patient&#39;s defective aortic valve against the valve annulus, retaining the native valve in a permanently open state. The outflow section of the valve prosthesis expands against and aligns the prosthesis within the ascending aorta, while the inflow section becomes anchored in the aortic annulus of the left ventricle, so that the skirt reduces the risk of perivalvular leaks. 
         [0062]    Alternatively, the valve prosthesis can be delivered through a transapical procedure. In a transapical procedure, a trocar or overtube is inserted into the left ventricle through an incision created in the apex of a patient&#39;s heart. A dilator is used to aid in the insertion of the trocar. In this approach, the native valve (e.g. the mitrel valve) is approached from the downstream relative to the blood flow. The trocar is retracted sufficiently to release the self-expanding valve prosthesis. The dilator is preferably presented between the valve leaflets. The trocar can be rotated and adjusted as necessary to properly align the valve prosthesis. The dilator is advanced into the left atrium to begin disengaging the proximal section of the valve prosthesis from the dilator. 
         [0063]    In an alternate aspect of the invention, the valve prosthesis can be delivered through a transatrial procedure. In this procedure, the dilator and trocar are inserted through an incision made in the wall of the left atrium of the heart. The dilator and trocar are advanced through the native valve and into the left ventricle of heart. The dilator is then withdrawn from the trocar. A guide wire is advanced through the trocar to the point where the valve prosthesis comes to the end of the trocar. The valve prosthesis is advanced sufficiently to release the self-expanding frame from the trocar. The trocar can be rotated and adjusted as necessary to properly align the valve prosthesis. The trocar is completely withdrawn from the heart such that the valve prosthesis self-expands into position and assumes the function of the native valve. 
         [0064]    The foregoing description has been presented for purposes of illustration and enablement, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Other modifications and variations are possible in light of the above teachings. The embodiments and examples were chosen and described in order to best explain the principles of the invention and its practical application and to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention.