CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/240,426, filed Sep. 22, 2011, which is a continuation of U.S. application Ser. No. 10/355,429, filed Jan. 31, 2003, which is a continuation of U.S. application Ser. No. 10/327,821, filed Dec. 20, 2002, and the disclosure of these applications are incorporated in their entireties by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a biologically implantable prosthesis, a heart valve assembly using the prosthesis, and methods of using the same within an annulus of the body. 
     2. Description of the Related Art 
     Prosthetic heart valves can replace defective human valves in patients. Prosthetic valves commonly include sewing rings or suture cuffs that are attached to and extend around the outer circumference of the prosthetic valve orifice. 
     In a typical prosthetic valve implantation procedure, the heart is incised and the defective valve is removed leaving a surrounding area of locally tougher tissue. Known heart valve replacement techniques include individually passing sutures through the tough tissue to form an array of sutures. Free ends of the sutures are extended out of the thoracic cavity and laid, spaced apart, on the patient&#39;s body. The free ends of the sutures are then individually threaded through an edge around the circumference of the sewing, ring. Once all sutures have been run through the ring, all the sutures are pulled up taught and the prosthetic valve is slid or “parachuted” down into place adjacent the tough tissue. Thereafter, the prosthetic valve is secured in place by traditional knot tying with the sutures. 
     The sewing ring is often made of a biocompatible fabric through which a needle and suture can pass. The prosthetic valves are typically sutured to a biological mass or annulus that is left when the surgeon removes the existing valve from the patient&#39;s heart. The sutures are tied snugly, thereby securing the sewing ring to the annulus and, in turn, the prosthetic valve to the heart. 
     Sewing rings can be tedious to secure to the valve orifice. Further, attaching the sewing ring, to the annulus can be time consuming and cumbersome. The complexity of suturing provides a greater opportunity for mistakes and requires a patient to be on cardiopulmonary bypass for a lengthy period. It is, also desirable to provide as large of a lumen through the prosthetic valve as possible to improve hemodynamics. However, techniques for attaching the sewing ring to the orifice typically require the area of the valve lumen be reduced to accommodate an attachment mechanism. For example, the sewing ring is typically retained on top of the annulus, resulting in a lumen that is, at the largest, the size of the original lumen. 
     A patient can also have a natural valve lumen that is detrimentally small. In these cases, the natural valve can be gusseted before the prosthetic valve is implanted. To gusset the natural valve, a longitudinal incision can be made along the wall of the lumen. The lumen can then be circumferentially expanded and the now-expanded incision can be covered with a patch graft or other membrane and stitched closed. 
     U.S. Pat. No. 4,743,253 to Magladry discloses a suture ring with a continuous compression ring. Magladry&#39;s ring is ductile, but provides a compressive, not expansive, force. In fact, the ring taught by Magladry is intended for placement over a heart valve and provides compression on the heart valve. 
     U.S. Pat. No. 6,217,610 to Carpentier et al. discloses an expandable annuloplasty ring. Carpentier et al. teach expanding the ring over the life of a patient by increasing the size of the ring by balloon dilatation. The ring is intended to remodel the shape of the valve annulus, not serve as a foundation to attach a second prosthesis and form a heart valve. 
     U.S. Pat. No. 5,984,959 to Robertson et al. discloses an expandable heart valve ring, for attaching a synthetic valve thereto and a tool for attaching the ring to the synthetic valve. Robertson et al. reach the ring as having tabs that are used to attach to the second prosthesis by using a second device to engage the tabs. 
     There is a need for a circumferentially expandable bio-prosthesis. There is also a need for a prosthesis and method that can expand an annulus and maintain an enlarged annulus circumference. Furthermore, there is a need for a minimally invasive heart valve replacement procedure. Also, there is a need for a prosthesis that can provide for the above and engagement with a second prosthesis, for example, the crown of a heart valve. Furthermore, there is a need for the above prosthesis that can self-engage a second prosthesis to improve implantation time. 
     BRIEF SUMMARY OF THE INVENTION 
     One embodiment of the disclosed prosthesis is a biologically implantable first prosthesis for a heart valve having a circumferentially expandable wall. The wall has a latitudinal cross-section perpendicular to the longitudinal axis, and a longitudinal cross-section parallel to the longitudinal axis. The prosthesis also has an engagement element configured to self-engage a second prosthesis. 
     The first prosthesis can also have a stop, where the stop prevents the wall from circumferentially decreasing. The first prosthesis can also have a fixturing device connector. The wall can also be corrugated. The wall can also have a turned lip, on its leading, edge. The first prosthesis can also be in an assembly where the first prosthesis can receive a second prosthesis, for example a crown. 
     Another embodiment of the prosthesis is a biologically implantable first prosthesis for a heart valve having a wall with a first edge and a second edge. The wall has a longitudinal axis at the center of the first prosthesis, and the first edge has an engagement element for engaging a second prosthesis. The engagement element is also turned toward the second edge. 
     The engagement element can be curved toward the second edge. The first edge can be the leading edge. The first prosthesis can also have a fixturing device connector that can be a port in the wall. The wall can also be corrugated. The first prosthesis can also be in an assembly with a second prosthesis connected to the engagement element. The second prosthesis can be a crown. 
     An embodiment of a method of implanting a heart valve in a valve annulus is attaching a first prosthesis to the valve annulus and attaching a second prosthesis to the first prosthesis. The first prosthesis has a circumferentially expandable wall. The wall has a longitudinal axis, and the wall has a latitudinal cross-section perpendicular to the longitudinal axis. 
     The first prosthesis can be a ring. The second prosthesis can be a crown. The wall of the first prosthesis can have a first terminal end and a second terminal end. Attaching the first prosthesis can include fixing the first prosthesis to a biological mass with a fixturing device. Attaching the first prosthesis can also include snap-fitting the second prosthesis to the first prosthesis. 
     Another embodiment of a method of implanting a heart valve in a valve annulus includes attaching a first prosthesis to, the valve annulus and attaching a second prosthesis to the first prosthesis. The first prosthesis has a wall having a first edge and a second edge. The wall also has a longitudinal axis. The first edge comprises an engagement element, and the engagement element is turned toward the second edge. 
     The engagement element can be turned away from the longitudinal axis. The first prosthesis can be a ring. The second prosthesis can be a crown. Attaching the crown can include snap-fitting the crown to the first prosthesis. 
     An embodiment of a method of increasing and maintaining the size of a biological valve annulus includes placing a circumferentially expandable first prosthesis in the annulus. The method also includes circumferentially expanding the first prosthesis, and circumferentially locking the first prosthesis. 
     Circumferentially expanding the first prosthesis can include increasing the radius of the annulus from about 0.1 mm (0.004 in.) to more than about 2.0 mm (0.08 in.). The first prosthesis can also have an engagement element configured to receive a second prosthesis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a bottom view of an embodiment of the prosthesis. 
         FIG. 2  is a top perspective view of the embodiment of the prosthesis of  FIG. 1 . 
         FIG. 3  is a bottom view of another embodiment of the prosthesis. 
         FIG. 4  is a top perspective view of the embodiment of the prosthesis of  FIG. 3 . 
         FIG. 5  is a bottom view of another embodiment of the prosthesis. 
         FIG. 6  is a top perspective view of the embodiment of the prosthesis of  FIG. 5 . 
         FIG. 7  is a bottom view of another embodiment of the prosthesis with cut-away views of the collars. 
         FIG. 8  is a top perspective view of the embodiment of the prosthesis of  FIG. 7  with cut-away views of the collars. 
         FIG. 9  is a bottom view of another embodiment of the prosthesis with cut-away views of the collars. 
         FIG. 10  is a top perspective view of the embodiment of the prosthesis of  FIG. 8  with cut-away views of the collars. 
         FIG. 11  is a top perspective view of another embodiment of the prosthesis with magnets. 
         FIG. 12  illustrates cross-section A-A of  FIG. 11 . 
         FIG. 13  is a top perspective view of another embodiment of the prosthesis with magnets. 
         FIG. 14  illustrates cross-section B-B of  FIG. 13 . 
         FIG. 15  is a top perspective view of another embodiment of the prosthesis with magnets. 
         FIGS. 16-18  are top views of various deformable embodiments of the prosthesis in unexpanded states. 
         FIG. 19  is a top view of the embodiment of the prosthesis of  FIG. 12  in an expanded state. 
         FIGS. 20-22  illustrate various embodiments of the fixturing device connectors. 
         FIGS. 23-25  illustrate various embodiments of the receiving elements. 
         FIGS. 26 and 27  are cut-away views of various embodiments of the receiving elements. 
         FIGS. 28-33  illustrate various embodiments of the protrusions. 
         FIG. 34  illustrates the steering elements. 
         FIGS. 35-43  are cross-sections of various embodiments of the wall of the prosthesis. 
         FIG. 44  illustrates an embodiment of the prosthesis of  FIG. 38 . 
         FIGS. 45 and 46  illustrate cross-sections of the wall of the prosthesis with various embodiments of the covering. 
         FIGS. 47-52  illustrate various embodiments of the engagement element. 
         FIG. 53  is a cut-away view of an embodiment of positioning the prosthesis in an annulus with a solid view of the prosthesis. 
         FIG. 54  is a cut-away view of an embodiment of positioning the prosthesis in an annulus. 
         FIGS. 55 and 56  illustrate various embodiments of the protrusions and receiving elements when the prosthesis is not expanded. 
         FIG. 57  is a cut-away view of an embodiment of expanding the prosthesis. 
         FIGS. 58 and 59  illustrate an embodiment of an expansion tool. 
         FIGS. 60 and 61  illustrate another embodiment of an expansion tool. 
         FIGS. 62 and 63  illustrate various embodiments of the protrusions and receiving elements when the prosthesis is expanded. 
         FIG. 64  is a cut-away view of fixturing the prosthesis to a biological mass. 
         FIGS. 65-68  illustrate an embodiment of a method and assembly for fixturing the prosthesis to a biological mass. 
         FIG. 69  is a cut-away view of positioning the second prosthesis onto the first prosthesis with a solid view of the second, prosthesis. 
         FIG. 70  is a cut-away view of attaching the second prosthesis to the first prosthesis.  FIGS. 71-77  are exploded views of various embodiments of attaching the second prosthesis to the first prosthesis. 
         FIG. 78  is ail exploded view of an embodiment of attaching the second prosthesis to an adapter and attaching the adapter to the first prosthesis. 
         FIGS. 79 and 80  illustrate cross-sections C-C and D-D, respectively, from  FIG. 78 . 
         FIG. 81  is a top view of an embodiment of the first prosthesis with the second prosthesis attached thereto. 
         FIGS. 82-84  illustrate an embodiment of a method of removing the second prosthesis from the first prosthesis. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  illustrate an embodiment of a biologically implantable first prosthesis  2 . The first prosthesis  2  can have a wall  4 . The wall  4  can have material strength and dimensions known to one having ordinary skill in the art to make the first prosthesis resiliently expandable. The wall  4  can have an open form or spiral longitudinal cross-section, as shown in  FIG. 1 . The longitudinal cross-section can be perpendicular to a central longitudinal axis  6 . 
     The wall  4  can have a first terminal end  8  and a second terminal end  10 . Each end  8  and  10  can be defined from a midpoint  12  of the wall  4  to a first terminus  14  or a second terminus  16  of the wall  4  at the respective end  8  or  10 . The wall  4  can have an end difference length  18 . The end difference length  18  can be the shortest angular length from the first terminus  14  to the second terminus  16 . The wall  4  can also have a leading edge  20  and a trailing edge  22 . The leading edge  20  and trailing edge  22  can be substantially perpendicular to the longitudinal axis  6 . The first prosthesis  2  can have a circumference equivalent to a wall length  24  minus an end difference length  18 . The wall  4  can have a wall height  25 . The wall height can be from about 3.18 mm (0.125 in.) to about 12.7 mm (0.500 in.), for example about 8.26 mm (0.325 in.). The wall  4  can also be void of any attachment device with which to fix one end  8  or  10  of the wall  4  to the other end  8  or  10  of the wall  4 . The wall  4  can made from stainless steel alloys, nickel titanium alloys (e.g., Nitinol), cobalt-chrome alloys (e.g., ELGILOY® from Elgin Specialty Metals, Elgin, Ill.; CONICHROME® from Carpenter Metals Corp., Wyomissing, Pa.), polymers such as polyester (e.g., DACRON® from E. I. Du Pont de Nemours and Company, Wilmington, Del.), polypropylene, polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE), polyether ether ketone (PEEK), nylon, extruded collagen, silicone, radiopaque materials or combinations thereof. Examples of radiopaque materials are barium, sulfate, titanium, stainless steel, nickel-titanium alloys and gold. 
       FIGS. 3 and 4  illustrate an embodiment of the first, prosthesis  2  that can be mechanically expandable. A first protrusion  26  and a second protrusion  28  at the first terminal end  8  can extend from the wall  4 . The protrusions  26  and  28  can extend perpendicular to the wall  4  or perpendicular to the longitudinal axis  6 . The protrusions  26  and  28  can be tabs, brads, extensions, balls, rods or a combination thereof. The protrusions can have a protrusion depth  30  sufficient to retain the wall  4 . 
     The wall  4  can also have a first receiving element  32  and a second receiving element  34  at the second terminal end  10  that receive or engage the first protrusion  26  and the second protrusion  28 , respectively. The wall  4  can also have more or less (e.g., one or zero) receiving elements  32  or  34 . The receiving elements  32  and  34  can be holes in the wall  4 . The receiving elements  32  and  34  can also be divets, dimples, hooks, slots, or a combination thereof. The protrusions  26  and  28  and receiving elements  32  and  34  can act together as a stop, or an interference fit, to prevent the first prosthesis  2  from circumferentially extending or decreasing beyond desired limits. 
       FIGS. 5 and 6  illustrate an embodiment of the first prosthesis  2  that can have protrusions  26  and receiving elements  32  that can be dimples. The protrusions  26  and receiving elements  32  can be in a first row  36 , a second row  38 , and additional rows  40 . The protrusions  26  can also be in a first column  42 , a second column  44 , and additional columns  46 . The receiving elements  32  can have a receiving element depth  46  within the same range of sizes as the protrusion depth  36 , above. 
       FIGS. 7 and 8  illustrate an embodiment of the first prosthesis  2  that can have the protrusions  26  and  28  extending from the first terminus  14  substantially at a tangent to the wall  4 . The protrusions  26  and  28  can be rods  48  with balls  50  at the ends of the rods  48 . The receiving elements  32  and  34  can extend from the second terminus  16  substantially at a tangent to the wall  4 . The receiving elements  32  and  34  can be collars  52  for receiving the balls  50 . The wall  4  can have a longitudinal cross-section in the shape of a circular open curve, as shown in  FIG. 7 . A circumferential gap  54  can exist between the first terminus  14  and the second terminus  16 . 
       FIGS. 9 and 10  illustrate an embodiment of the first prosthesis  2  that can have different embodiments of protrusions  26  and  28  and receiving elements  32  and  34 . The first prosthesis  2  of  FIGS. 9 and 10  can also have a wall angle  56  relative to the longitudinal axis  6  controlled by the dimensions of the protrusions  26  and  28  and receiving elements  32  and  34  and the locations of the protrusions  26  and  28  and receiving elements  32  and  34  on the wall  4 . The wall angle  56  can be from about 10° to about 60°, more narrowly from about 20° to about 45°, for example about 25°. The protrusions  26  and  28  and the receiving elements  32  and  34  can be located along the trailing edge  22 , the leading edge  20  or therebetween. 
       FIGS. 11 and 12  illustrate an embodiment of the first prosthesis  2  with the wall  4  having a bottom segment  58  and a top segment  60 . The first prosthesis  2  can be deformably circumferentially expandable. The bottom segment  58  can have the wall angle  56  relative to the longitudinal axis  6 . The angle between the bottom segment  58  and the top segment  60  can be a joint angle  62 . The joint angle  62  can be from about 90° to about 180°, more narrowly from about 90° to about 160°, for example about 120°. 
     The wall  4  can also have a first steering groove  64  that can extend over the length of the bottom segment  58 . The wall  4  can also have a second steering, groove  66  that can extend over a portion of the length of the bottom segment  58 . The grooves  64  and  66  can help angularly align, with respect to, the longitudinal axis  6 , a second prosthesis  68  that can be attached to the first prosthesis  2 . The grooves  64  and  66  can also prevent the rotation of the first prosthesis  2  with respect to the second prosthesis  68 . The second groove  66  can also help to longitudinally align the second prosthesis  68 . 
     The first prosthesis  2  can also have engagement elements, for example top magnets  70  in the top segment  60  and bottom magnets  72  in the bottom segment  58 . The magnets  70  and  72  can have a magnet height  74 , a magnet width  76  and a magnet length  78 . The magnets  70  and  72  can be rare earth, high strength-type magnets. The magnets can be made from neodymium-iron-boron and can be encapsulated in a coating made from PTFE (e.g., TEFLON® (from E. I. Du Pont de Nemours and Company, Wilmington, Del.), PEEK, a similarly inert and stable biocompatible polymer, or a combination thereof. A radiopaque material can also be added to the coating. The top and/or, bottom magnets  70  and/or  72  can be customized to allow for only one angular orientation of the second prosthesis  68  by changing the polarity of one or an irregular number of magnets  70  and/or  72  (e.g., positive) to be different from the polarity of the remaining magnets  70  and/or  72  (e.g., negative). 
     In one example, 24 magnets  70  can be evenly distributed around the circumference of the first prosthesis  2 . The magnet heights  74  can be about 3.175 mm (0.125 in.). The magnet widths  76  can be about 3.175 mm (0.125 in.). The magnet lengths  78  can be about 1.59 mm (0.0625 in.). 
       FIGS. 13 and 14  illustrate an embodiment of the first prosthesis  2  similar to the embodiment illustrated in  FIGS. 11 and 12 . The present embodiment of the first prosthesis  2  can have a cloth sewing surface  80 . The magnets  70  can be square or rectangular in cross-section (as shown in  FIGS. 11 and 12 ) or oval or circular in cross-section (as shown in  FIGS. 13 and 14 ). The wall  4  can also be multiple segments  58  and  60 , as shown in  FIGS. 11 and 12 , or a single segment, as shown in  FIGS. 13 and 14 . 
       FIG. 15  illustrates an embodiment of the first prosthesis  2  similar to the embodiment illustrates in  FIGS. 11 and 12 . The first prosthesis  2  in the present embodiment can also be mechanically and/or resiliently circumferentially expandable. 
       FIGS. 16-18  illustrates deformable embodiments of the first prosthesis  2 . In an unexpanded state, the first prosthesis  2  can have an unexpanded diameter  82 . The embodiment of the first prosthesis  2  in  FIG. 16  can have a smooth wall  4 , thereby relying on hoop strain to expand. In  FIG. 17 , the embodiment can have an accordianed wall  4  with multiple pleats or folds  84 . The folds  84  can open or unfold to maximize circumferential expansion of the wall  4  during use. The embodiment of the first prosthesis  2  in  FIG. 18  can have a single large fold  84  for the same purpose as the folds  84  shown in  FIG. 17 ,  FIG. 1.9  illustrates a deformable embodiment of the first prosthesis  2  in an expanded state. A radial force, as shown by arrows, directed away from the longitudinal axis  6  can expand the first prosthesis  2  to an expanded diameter  86 . Materials and dimensions of the first prosthesis  2  can be selected by one having ordinary skill in the art to permit the ratio of the unexpanded diameter  82  to the expanded diameter  86  to be from about 0% to about 50%, more narrowly from about 5% to about 20%, yet more narrowly from about 9% to about 12%, for example about 9.5%. 
       FIG. 20  illustrates a length of the wall  4  that can have a first fixturing device connector  88  and a second fixturing device connector  90 . The fixturing device connectors  88  and  90  can be ports or holes in the wall  4 . The fixturing device connectors  88  and  90  can be ovular and can have a fixturing device connector height  92  and a fixturing device connector length  94 . The fixturing device connector height  92  can be from about 0.51 mm (0.020 in.) to about 3.18 mm (0.125 in.), more narrowly from about 1.0 mm (0.040 in.) to about 1.5 mm (0.060 in.), for example about 1.3 mm (0.050 in). 
       FIG. 21  illustrates a length of the wall  4  that can have first, second, and additional fixturing device connectors  88 ,  90  and  96 . The fixturing device connectors  88 ,  90  and  96  can be circular in shape.  FIG. 22  illustrates a length of the wall  4  that can have the fixturing device connectors  88 ,  90  and  96  attached to the leading and trailing edges  20  and  22 . The fixturing device connectors  88 ,  90  and  96  can be made from fabric or metal, for example polymers such as polyester (e.g., DACRON® from E. I. Du Pont de Nemours and Company, Wilmington, Del.), polypropylene, PTFE, ePTFE, nylon, extruded collagen, silicone, stainless steel alloys, nickel-titanium alloys (e.g., Nitinol), cobalt-chrome alloys (e.g., ELGILOY® from Elgin Specialty Metals, Elgin, Ill., CONICHROME® from Carpenter Metals Corp., Wyomissing, Pa.) or combinations thereof. Variously shaped and configured fixturing device connectors  88 ,  90  and  96  can be on the same wall  4 . 
       FIG. 23  illustrates a length of the wall  4  that can have the receiving elements  32  and  34 . The receiving elements  32  and  34  can be ports or holes in the wall  4 . The receiving elements  32  and  34  and the fixturing device connectors  88 ,  90  and  96  can be the same element. The receiving elements  32  and  34  can have a first setting position  98  and a first neck  100  at one end of the first setting position  98 . The first setting position  98  can have a setting position length  102  from about 4 mm (0.2 in.) to about 10 mm (0.4 in.), for example about 6.3 mm (0.25 in.). The first neck  100  can have a neck width  104 . The first neck  100  can be at a first end of a second setting position  106 . The receiving elements  32  and  34  can have more or less than two setting, positions  98  and  106  (e.g., one or zero). At a second end of the second setting position  106 , the second setting position  106  can have a second neck  108 . The second neck  108  can be at a first end of a final stop position  110 . The final stop position  110  can have a final stop length  112 . 
     The first and second setting positions  98  and  106  can lead to the first and second necks  100  and  108 , respectively, with a ramp angle  114 . The stop position  110  and the second setting position  106  can lead to the second  108  and first necks  100 , respectively, with a stop angle  116 . 
       FIG. 24  illustrates narrowing, oval or teardrop-shaped receiving elements  32  and  34 .  FIG. 25  illustrates rectangular receiving elements  32  and  34 . 
       FIG. 26  illustrates the receiving element  32  that can be in the shape, of a collar or sleeve. The receiving element  32  can be attached by a connection zone  118  to a rod (not shown) extending from the wall  4  or to the wall  4  itself. The receiving element  32  can have first wedges  120  and second wedges  122 . The length between the closest point of the first wedges  120  or of the second wedges  122  can be the neck width  104 . The wedges  120  and  122  can revolve around the entire receiving element  32 , thereby forming a single, circular first wedge  120  and a single, circular second wedge  122  (when seen in three-dimensions). 
     A receiving element shaftway  124  can be open at one end of the receiving element  32 . The receiving element  32  can have a first narrowing  126  near the connection zone  118  and a second narrowing  128  near the receiving element shaftway  124 .  FIG. 27  illustrates the receiving element  32  that can have the wedges  120  and  122  shaped as scales or stop tabs. 
     A length of the wall  4  that can have protrusions  26  and  28  is illustrated in  FIG. 28 . The protrusions  26  and  28 , shown alone in various embodiments in  FIGS. 29 and 25 , can be made from an extension  130  and a cuff  132 . The extension  130  can be shaped cylindrically or, as shown in  FIG. 30 , as a shaft with a triangular cross-section. The extension  130  can have an extension height  134  and an extension width  136 . The extension height  134  can be from about 0.51 mm (0.020 in.) to about 2.54 mm (0.100 in.), for example about 1.3 mm (0.050 in.). The final stop length  112  can be from about the extension width  136  to about 10 mm (0.4 in.), for example about 6.3 mm (0.25 in.). 
     The cuff  132  can be shaped as a circle or a square and can be substantially flat in depth. The cuff  132  can, have a cuff height  138  and a cuff width  140 . The cuff height  138  can be from about the fixturing device connector height  92  to about 5.08 mm (0.200 in.), for example about 2.0 mm (0.080 in). The cuff width  140  can be within the range for the cuff height  138 , above. 
       FIG. 31  illustrates a length of the wall  4  having the protrusions  26  and  28  formed from tabs cut out of the wall  4 . Cut holes  142  can exist in the wall  4  where the material in the protrusions  26  and  28  was located in the wall  4  before being cut out. 
       FIG. 32  illustrates a length of the wall  4  that can have a first set and a second set of protrusions  26  and  28  extending from the wall  4 . The wall  4  can have a wall radius of curvature  144 . The protrusions  26  and  28  can have protrusion radii of curvature  146 . 
     The protrusion radii of curvature  146  can be from about the wall radius of curvature  144  to infinity. 
       FIG. 33  illustrates a length of the wall  4  that can have an engagement element  148 . The engagement element  148  can be shaped as a lip and wrapped around the protrusion  26 . The engagement element  148  can enable the first prosthesis  2  to self-engage the second prosthesis  68 . For example, the engagement element  148  can snap-fit to the second prosthesis  68 . 
       FIG. 34  illustrates the first terminal end  8  and the second terminal end  10 . The second terminal end  10  can have a first guide  150  and a second guide  152  that can wrap around the leading edge  20  and the trailing edge  22 , respectively, of the first terminal end  8 . The first terminal end  8  can slide angularly, with respect to the longitudinal axis  6 , within the guides  150  and  152 . The guides  150  and  152  can also minimize the risk of the first terminal end  8  moving too far away from or becoming misaligned from the second terminal end  10 . 
       FIGS. 35-43  illustrate embodiments of the first prosthesis  2  at a latitudinal cross-section. The latitudinal cross-section can be a cross-section parallel with the longitudinal axis  6 .  FIG. 35  illustrates an embodiment with the wall  4  having a corrugated latitudinal cross-section.  FIG. 36  illustrates an embodiment with the wall  4  having a straight latitudinal cross-section, parallel with the longitudinal axis  6 . 
       FIG. 37  illustrates an embodiment having the trailing edge  22  angled toward the longitudinal axis  6  at the wall angle  56 .  FIG. 38  illustrates an embodiment having the trailing edge  22  angled away from the longitudinal axis  6  at the wall angle  56 . 
       FIG. 39  illustrates an embodiment having a wall  4  convex toward the longitudinal axis  6 . The wall  4  can be straight or have a lateral convex radius of curvature  154 .  FIG. 40  illustrates an embodiment having a wall  4  concave toward the longitudinal axis  6 . The wall  4  can have a lateral concave radius of curvature  156  within the same range as the lateral convex radius of curvature  154 . 
       FIG. 41  illustrates an embodiment having a wall  4  with a top segment  60 , a middle segment  158  and a bottom segment  58 . The top segment  60  and leading edge  20  can be angled away from the longitudinal axis  6 . The bottom segment  58  and trailing edge  22  can be angled away from the longitudinal axis  6 . The middle segment  158  can remain parallel to the longitudinal axis  6 . 
       FIG. 42  illustrates an embodiment having the top segment  60  and the leading edge  20  that can be angled toward the longitudinal axis  6 . The bottom segment  58  and trailing edge  22  can also be angled toward the longitudinal axis  6 . The middle segment  158  can remain parallel to the longitudinal axis  6 . 
       FIGS. 43 and 44  illustrate an embodiment of the wall  4  that can have a bottom segment  58  that can extend from the wall  4  at a retainer angle  160  with respect to the longitudinal axis  6  from about 0° to about 90°, more narrowly from about 10° to about 50°, for example about 30°. The bottom segment  58  can also have cuts  162 , shown in  FIG. 44 . The cuts  162  can minimize stresses when the bottom segment  58  fans away from the middle segment  158 . The bottom segment  58  can also act as a retention element, extending beyond the typical trailing edge  22  and stabilizing the first prosthesis  2  after the first prosthesis  2  is implanted. 
       FIG. 45  illustrates a cross-section of the wall  4  that can have a fabric covering  164 , for example polyester (e.g., DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), polypropylene, PTFE, ePTFE, nylon, extruded collagen, silicone or combinations thereof. The fabric can be attached to the wall  4  at a first attachment point  166  and a second attachment point  168 . The bare area of the wall between the attachment points  166  and  168  can be the engagement surface  170 . The second prosthesis  68  can engage the first prosthesis  2  at the engagement surface  170 . 
       FIG. 46  illustrates a cross-section of the wall  4  covered entirely by the covering  164 . The second prosthesis  68  can also engage the first prosthesis  2  at the engagement surface  170  covered by the covering  164 . 
       FIG. 47  illustrates a length of wall  4  with the engagement element  148 , shaped as an open lip, on the leading edge  20 . The engagement element  148  can be turned toward the longitudinal axis  6  and toward the trailing edge  22 .  FIG. 48  illustrates the engagement element  148  turned away from the longitudinal axis  6  and toward the trailing edge  22 . 
       FIGS. 49 and 50  illustrate an embodiment of the first prosthesis  2  that can have a first length  172 , a second length  174  and a third length  176 . The lengths  172 ,  174  and  176  can be separated by cuts  162  in the wall  4 . The engagement element  148  on the first length  172  and third length  176  can turn toward the longitudinal axis  6 . The top and middle segments  60  and  158  of the first length  172  and the third length  176  can be bent away from the bottom segment  58  as shown by the arrows in  FIG. 50 . The top and middle segments  60  and  158  of the second length  174  can be similarly bent but in the opposite direction to the top and middle segments  60  and  158  of the first and third lengths  172  and  176 . The engagement element  148  on the second length  174  can turn away from the longitudinal axis  6 . A lip length  178  can be the length between, a first lip edge  180  of the engagement element  148  on the first length  172  or third length  176  and a second lip edge  182  of the engagement element  148  on the second length  174 . The lip length  178  can be small enough to form a seam, crease or seat  184  to aid in seating, receiving and engaging a second prosthesis. 
       FIG. 51  illustrates a length of the wall  4  that can have the lengths  172 ,  174  and  176 . The engagement elements  148  on the first length  172  and third length  176  can turn away from the longitudinal axis  6 . The engagement element  148  on the second length  174  can turn toward the longitudinal axis  6 . The engagement element  148  can then engage a second prosthesis on both sides of the wall  4 . 
       FIG. 52  illustrates an embodiment that can have springs  186 . One segment of each spring  186  can be a latch  188 . The springs  186  can have windings  190  around a rail  192  fixed under the engagement element  148 . The springs  186  can also have retaining legs  194  pressed against the wall  4 . The latches  188  can be biased to contract, as shown by arrows  196 , against the wall  4 . The latches  188  can be held in the uncontracted position shown in  FIG. 52  by interference beams  198 . The interference beams  198  can be directly or indirectly rigidly attached to each other at a proximal end (in the direction, of arrows  200 ) to minimize the interference beams  198  from deflecting under the force, shown by arrows  196 , from the latches  188 . The interference beams  198  can be removed, as shown by arrows  200 , allowing the latches  188  to contract, as shown by arrows  196 , against, for example, the second prosthesis, once the second prosthesis is positioned within the reach of the latches  188 . 
     Method of Making 
     The wall  4  can be made from methods known to one having, ordinary skill in the art. For example, the wall  4  can be molded or machined. The engagement element  148 , the corrugation and any other bends in the wall  4  can be formed (e.g., pressure formed), molded or machined into the wall  4  or bent into the metal with methods known to one having ordinary skill in the art. 
     The protrusions  26  and  28  and the receiving elements  32  and  34  (e.g., at the connection zone  118 ) can be fixed to the to the wall  4  or formed of the wall  4  by crimping, stamping, melting, screwing, gluing, welding, die cutting, laser cutting, electrical discharge machining (EDM) or a combination thereof. Cuts  162  and holes in the wall  4  can be made by die cutting, lasers or EDM. 
     Any part of the first prosthesis  2 , or the first prosthesis  2  as a whole after assembly, can be coated by dip-coating or spray-coating methods known to one having ordinary skill in the art. One example of a method used to coat a medical device for vascular use is provided in U.S. Pat. No. 6,358,556 by Ding et al. and hereby incorporated by reference in its entirety. Time release coating methods known to one having ordinary skill in the art can also be used to delay the release of an agent in the coating. The coatings can be thrombogenic or anti-thrombogenic. For example, coatings on the inside of the first prosthesis  2 , the side facing the longitudinal axis  6 , can be anti-thrombogenic, and coatings on the outside of the first prosthesis, the side facing away from the longitudinal axis  6 , can be thrombogenic. 
     The first prosthesis  2  can be covered with a fabric, for example polyester (e.g., DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), polypropylene, PTFE, ePTFE, nylon, extruded collagen, silicone or combinations thereof. Methods of covering an implantable device with fabric are known to those having ordinary skill in the art. 
     Method of Use 
     The first prosthesis  2  can be introduced in an unexpanded state to an antechamber  202  adjacent to a targeted valve annulus  204  by methods known to one having ordinary skill in the art.  FIG. 53  illustrates positioning and lowering, as shown by the arrows, the first prosthesis  2  to the annulus  204 . Because of the collapsible and expandable nature of the first prosthesis  2 , the procedure of implanting the first prosthesis  2  can be accomplished thorascopically, endoscopically and/or endoluminally. The first prosthesis  2  can be placed accurately enough into the annulus  204  so that the first prosthesis  2  does not block vessel openings in chambers neighboring the annulus  204  (e.g., the openings for the coronary vessels) and does not fall out of the annulus  204  (e.g., into a chamber of the heart, a ventricle for example). The annulus  204  can have an initial annulus diameter  206 .  FIG. 54  illustrates positioning and seating the first prosthesis  2 . 
     When the first prosthesis  2  is completely unexpanded, the protrusion  26  and the receiving element  32  can be aligned as illustrated in  FIGS. 55 and 56 . As shown in  FIG. 55 , the extension  130  can be located in the first setting position  98 . As shown in  FIG. 56 , the ball  50  can be located in the first setting position  98 . 
     The first prosthesis  2  can be circumferentially expanded, as illustrated by the arrows in  FIG. 57 . The prosthesis can have an expanded annulus diameter  208 . The expanded annulus diameter  208  can, be from about 5 mm (0.2 in.) to about 40 mm (1.6 in.), depends on, the size of the initial annulus diameter  206 , and can be influenced, by other anatomy, anomalies (e.g., narrowing, stenosis) and, age (e.g., pediatric sizing). An expansion tool  210  can be used to expand the first prosthesis  2 . Examples of the expansion tool  210  include a balloon, back sides of a clamp jaws, or a flexible plug assembly as shown in  FIGS. 58-61 . Another example of the expansion tool  210  is disclosed in U.S. Pat. No. 5,984,959 to Robertson et al. which is herein incorporated by reference in its entirety. 
       FIG. 58  illustrates a flexible plug  212  that can be cylindrical and have a static plate  214  on a first side  216 . The plug  212  can be made from polymers, for example polyurethane or silicone. The plug  212  can have a hole  218  in the center of the plug  212 . A rigid inner tube  220  can pass through the hole  218  and be tied into a knot or pull against a washer  222  on the first side  216 . A squeeze plate  224  can be fixedly attached to an end of a rigid outer tube  226 . The outer tube  226  can be larger than the inner tube  220 , and the inner tube  220  can slide through the outer tube  226 . A force in the direction of the plug  212  can be applied to the outer tube  226 , as shown by arrows  228 . A force in the direction away from the plug  212  can be applied to the inner tube  220 , as shown by arrows  230 . The plug can have a resting diameter  232  when no forces are applied. 
     Once the forces shown by the arrows  228  and  230  are applied to the plug  212 , the plug  212  can deform away from the tubes  220  and  226 , as shown by arrows  234  and illustrated in  FIG. 59 . Once deformed, the plug  212  can have an expanded diameter  236 . The resting diameter  232  and the expanded diameter  236  can be sized appropriately to the dimensions of the first prosthesis  2 . The deformation of the plug  212  can also create forces in the same direction as the arrows  234 . When the forces shown by the arrows  228  and  230  are removed, the plug  212  can return to the shape shown in  FIG. 58 . 
       FIG. 60  illustrates another embodiment of the plug  212 . The plug  212  can have a recessed top surface  238  and a recessed bottom surface  240 . A top perimeter  242  and a bottom perimeter  244  can be angled from the recessed surfaces  238  and  240  to meet a wall  246  of the plug  212 . The squeeze plate  224  and the static plate  214  can both be conically or partially conically shaped to fit the perimeters  242  and  244  of the plug  212 . As shown in  FIG. 61 , when the forces shown by the arrows  228  and  230  are applied, the plug wall  246  can expand radially and maintain a flat surface. 
     When the first prosthesis  2  is completely expanded, the protrusion  26  and the receiving element  32  can be aligned as illustrated in  FIGS. 62 and 63 . As shown in  FIG. 62 , the extension  130  can be located in the final stop position  110 . As shown in  FIG. 63 , the ball  50  can be located in the final stop position  110 . The interference fit caused by the stop angle  116  and neck width  104  of the second neck  108  can prevent the protrusion  26  from re-entering, the second setting position  106 . In addition, when expanded the first prosthesis frictionally engages the annulus, expanding the annulus diameter. When expanded, the first prosthesis  2  can also trap vascular plaque between the wall  4  and the perimeter of the annulus  204 . The first prosthesis  2  can also be partially expanded, forcing the protrusion  26  into the second setting position  106 . 
     Fixturing devices  248  can be used to fix the first prosthesis  2  through the fixturing device connectors  88  to the biological mass of the annulus  204 , as shown in  FIG. 64 . Examples of fixturing devices  88  are sutures, clips, staples, pins and combinations thereof. 
       FIGS. 65-68  illustrate one embodiment of a method of fixing the first prosthesis  2  to the annulus  204 .  FIG. 65  illustrates an embodiment of a fixturing device assembly  250 . The fixturing device assembly  250  can have a needle  252 . The needle  252  can be curved or have a curved tip. The needle  252  can also be attached at a proximal end to a distal end of a line  254 . The proximal end of the needle  252  can also be attached directly to the can  256  without the line  254  or formed as the can  256 . A proximal end of the line  254  can be attached to a can  256 . The can  256  can be a flexible cylindrical storage device, for example a coil. The can  256  can removably hold the fixturing device  248 . The fixturing device  248  can have a fixturing element  258 , for example, a wire or fiber. The fixturing element  258  can, have a ball  260  at a first end and a radially expandable portion  262  at a second end. The fixturing device  248  can also have a pledget  264  on the fixturing element  258  between the ball  260  and the expandable portion  262 . 
     The fixturing device assembly  250  can be positioned so the needle  252  is adjacent to the fixturing device connector  88 , as shown by arrows  266 . The needle  252  can then be pushed through the fixturing device connector  88  and the annulus  204 , as shown by arrow  268  in  FIG. 66 . The needle  252  can then be pulled away from the annulus  204 , as shown by arrow  270  in  FIG. 67 . The can  256  can follow the path of the needle  252  through the annulus  204 , as shown by arrow  272 . The pledget  264  can also be larger than the fixturing device connector  88 , and the pledget  264  can provide an interference fit against the fixturing device connector  88 . The needle  252  can continue to be pulled away from the annulus  204 , pulling the can  256  out of the annulus  204 , as shown by arrow  274  in  FIG. 68 . The interference fit of the pledget  264  against the fixturing device connector  88  can provide a resistive force holding the fixturing device  248  and causing the fixturing element  258  to slide out of the can  256  as the needle  252  is pulled away from the annulus  204 . The radially expandable portion  262  can then radially expand, thereby causing the first prosthesis  2  and the annulus  204  to be fixed between the pledget  264  and the radially expandable portion  262 . 
     The inner surface of the can  256  can be designed—for example, by coiling, corrugation, or other roughening—to adjust the friction between the inner surface of the can  256  and the fixturing device  248 . This friction can influence the amount of resistive force necessary to remove the fixturing device  248  from the can  256 . The resistive force can be larger than about the force necessary to have the fixturing device  248  fall out of the can  256  before the fixturing device  248  has passed through the annulus  104 . The resistive force can also be less than about the force necessary to deform the pledget  264  sufficient to pull the pledget  256  through the fixturing device connector  88 . The resistive force can be, for example, about 1.1 N (0.25 lbs.). 
     A second prosthesis  68  can then be positioned on the engagement element  148 , as shown by the arrows in  FIG. 69 . Once seated on the engagement element  148 , the second prosthesis  68  can then be engaged by the first prosthesis  2 , as shown in  FIG. 70 . Examples of second prostheses  68  include a connection adapter and a heart valve crown with leaflets  276 , for example, U.S. Pat. No. 6,371,983 to Lane which is herein incorporated by reference in its entirety. 
       FIG. 71  illustrates another embodiment of the heart valve assembly  278  with the second prosthesis  68 . The first prosthesis  2  can have a tapered wall  280  to provide a longitudinal stop and to guide insertion of the second prosthesis  68  into the first prosthesis  2 , as shown by arrows  282 . The tapered wall  280  can also push back the annulus  204 , maintaining the expanded annulus diameter  208  when the second prosthesis  68  is engaged in the first prosthesis  2 . The second prosthesis  68  can have spring lock tabs  284  to fix to the engagement element  148 . The spring lock tabs  284  can angle outwardly from the longitudinal axis  6 . The first and second prostheses  2  and  68  can have first and second prosthesis diameters  288  and  290 , respectively. The first prosthesis diameter  288  can be larger than the second prosthesis diameter  290 .  FIG. 72  illustrates the embodiment of the heart valve assembly  278  of  FIG. 71 , however the second prosthesis diameter  290  can be larger than the first prosthesis diameter  288 , and the spring lock tabs  284  can angle inwardly toward the longitudinal axis  6 . The first prosthesis  2  and the second prosthesis  68  act to maintain the expanded annular lumen diameter  208 . 
       FIG. 73  illustrates another embodiment of the heart valve assembly  278  with a second prosthesis  68  that can have fixation points  286  that align with fixation points  286  on the first prosthesis  2  to allow insertion of sutures, grommets, clips  292  or pins  294  through the aligned fixation points  286  to fix the first prosthesis  2  to the second prosthesis  68 . 
       FIG. 74  illustrates another embodiment of the heart valve assembly  278  with a multi-lobed stiffening ring  296  that can be placed near the edge of the second prosthesis  68  as shown by arrows  298 . The second prosthesis  68  can have several flaps  300 . The flaps  300  can wrap around the stiffening ring  296 , as shown by arrows  302 . The wrapped stiffening ring  296  can increase the rigidity of the second prosthesis  68  and can engage, the engagement element  148 . 
       FIG. 75  illustrates yet another embodiment of the heart valve assembly  278  with an embodiment of the first prosthesis  2  equivalent to the embodiment in  FIG. 52 . The second prosthesis  68  can have latch openings  304  to receive the latches  188 . When the second prosthesis  68  is lowered into the first prosthesis  2 , the interference beams  198  can be removed, as shown by arrows  200 . The latches  188  can then contract onto the latch openings  304 . 
       FIG. 76  illustrates an embodiment of the heart valve assembly  278  with an embodiment of the first prosthesis  2  equivalent to the embodiment in  FIGS. 11 and 12 . The second prosthesis can have a rib  306  to fit within the groove  64 . The second prosthesis  68  can also have an upper arm  308  that can have a top magnet  70  and a lower arm  310  that can have a bottom magnet  72 . The magnets  70  and  72  in the second prosthesis  68  can have polarities opposite of the polarities of the corresponding magnets  70  and  72  in the first prosthesis  2 .  FIG. 77  illustrates an embodiment of the heart valve assembly  278  with an embodiment of the first prosthesis equivalent to the embodiment in  FIGS. 13 and 14 . 
       FIG. 78  illustrates an embodiment of the heart valve assembly  278  with an adapter  312  connecting the second prosthesis  68  to the first prosthesis  2 . The adapter  312  can have spring lock tabs  284  to fix to the engagement element  148 , and the adapter  312  can have a stop ridge  314  to position the adapter  312  against the wall  4 . 
     The adapter  312  can also have fixation points  286  that align with other fixation points  286  on the second prosthesis  68  to allow insertion of sutures, grommets, clips, pins, or the fixturing devices  248 , through the aligned fixation points  286  to fix the adapter  312  to the second prosthesis  68 . The second prosthesis  68  can also be lowered into the top of the adapter  312  as shown by arrow  316 . The adapter  312  can attach to the inside or outside of the first or second prosthesis  2  or  68  depending on the dimensions and the orientation of the attachment apparatus (e.g., unidirectional clips). 
     The adapter  312  can also have multiple shapes of cross-sections, as shown in  FIGS. 79 and 80 . As shown in  FIG. 79 , cross-section C-C can have three lobes  318  and three scallops  320 . One scallop  320  can be between each lobe  318 . Cross-section C-C can be the same as the cross-section of the second prosthesis  68  where the second prosthesis  68  engages the adapter  312 . As shown in  FIG. 80 , cross-section D-D can be circular. Cross-section D-D can be the same as the cross-section of the first prosthesis  2  where the first prosthesis  2  engages the adapter  312 . 
       FIG. 81  illustrates a second prosthesis  68  received by a first prosthesis  2 . The second prosthesis  68  can have three lobes  318 . The second prosthesis can have a scallop  320  between each two lobes  318 . The scallop gap  322  between each scallop  320  and the wall  4  can be covered by a fabric during use of the prostheses  2  and  68 . 
       FIG. 82  illustrates that a lever device  324 , for example a clamp or scissors, can be forced, as shown by arrows, into the scallop gap  322 . As illustrated in  FIG. 83 , once legs  326  of the lever device  324  are placed next to two scallops  320 , the lever device  324  can be squeezed, as shown by arrows, thereby crushing the second prosthesis  68  and separating it from the first prosthesis  2 . As illustrated in  FIG. 84 , the second prosthesis  68  can be removed from the first prosthesis  2 , as shown by arrows, once the second prosthesis  68  is separated from the first prosthesis  2 . Once the second prosthesis  68  is removed, a new second prosthesis  68  can be added as described above. Leaflet failure can be fixed easily and inexpensively by implanting a new second prosthesis  68 . Circumferential expansion of the first prosthesis  2  and replacement of the second prosthesis  68  to account for pediatric expansion of the valve can also be performed easily and inexpensively. 
     It is apparent to one skilled in the art that various changes and modifications can be made to this disclosure, and equivalents employed, without departing from the spirit and scope of the invention. Elements shown with any embodiment are exemplary for the specific embodiment and can be used on other embodiments within this disclosure.
A heart valve assembly comprises a first prosthesis configured to expand from an unexpanded state to an expanded state at which the first annular prosthesis contacts native tissue of a body lumen. The heart valve assembly also comprises a second prosthesis comprising a valve, and a connection adapter that secures the second prosthesis to the first prosthesis, the connection adapter having a multi-lobed circumference.