Abstract:
A medical valve implant comprising: an implant structure configured as a medical valve; and a base body that includes a collar extending in a circumferential direction around the implant structure, wherein the collar includes a first cell structure composed of a plurality of cells forming an inner cross section of the base body that is matched to an outer cross section of the implant structure, characterized in that the collar includes a second cell structure fastened to an inner contour of a cell of the first cell structure at two fastening points and configured to move radially outward relative to the first cell structure so that an outer contour of the base body is formed by the first cell structure and the second cell structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application is a continuation of U.S. patent application Ser. No. 13/218,147, filed Aug. 25, 2011, which claims benefit of priority to U.S. Provisional Patent Application No. 61/378,420, filed on Aug. 31, 2010, each of which is herein incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates to a medical valve implant for implantation in an animal body and/or human body. 
       BACKGROUND 
       [0003]    Implants are used in medical applications for implantation in an animal body and/or human body permanently or at least for an extended period of time to perform replacement functions. Valve implants are known, for example, such as aortic valve implants that perform the function of the natural aortic valve. 
         [0004]    Methods are known, for example, in which the diseased cusp is clamped between an arm of the implant and the aortic wall and, after the implant structure has been expanded, the valve implant assumes the position of the natural aortic valve. A valve implant of this type in the form of an artificial aortic valve is known e.g. from U.S. Pat. No. 2,926,312. The implant includes elastic structures such as arms and a circular collar which expand to form a circular shape upon implantation, thereby anchoring the implant using its forces that act on the aortic wall. 
         [0005]    A problem that occurs frequently with cardiac disease is calcification i.e. the deposition of calcium salts, in particular calcium phosphate (hydroxyapatite), on the structures of the heart. In fact, aortic stenosis that is calcified in a highly asymmetric manner occurs particularly frequently. Implanting a circularly expanding aortic valve implant into a stenosis that has calcified in this manner causes the stent body to deform, resulting in suboptimal functioning of the cusp. This manifests in the form of poorer pressure gradients and a shorter service life of the valve. Furthermore, self-expandable stents show premature signs of fatigue. 
       SUMMARY 
       [0006]    The problem addressed by the invention is that of creating a medical valve implant having improved functionality in cases of strong and/or asymmetrical calcifications at the implantation site. 
         [0007]    The invention is directed to a medical valve implant for implantation in an animal body and/or human body, comprising a base body that includes a collar that extends in the circumferential direction, wherein the collar has at least one first cell structure that is designed to form, in the intended end state, an intended inner cross section of the base body that is matched to an intended outer cross section of an implant structure. 
         [0008]    It is provided that the collar has at least one second cell structure that is movable relative to the at least first cell structure, and includes at least one contact point, wherein an outer contour of the base body is formed by the at least one first cell structure and at least the at least one contact point of the at least second cell structure, and wherein the at least one contact point forms at least one extreme point of the outer contour relative to a geometric center of gravity of the base body. 
         [0009]    A “valve implant” is intended to mean, in particular, a body that functions as a replacement for a non-return valve, permanently or at least for an extended period of time, when implanted in an animal body and/or human body. Other possibilities that are feasible are all medical valve implants that appear suitable to a person skilled in the art, such as an aortic valve, a pulmonary valve, a mitral valve, or a tricuspid valve; particularly advantageously, an embodiment of the medical implant as a stent, in particular a coronary stent, having an implant structure that is connected to the stent in a reversible or irreversible manner is provided. In this context, an “implant structure” is intended to mean, in particular, an aortic valve, a pulmonary valve, a mitral valve, or a tricuspid valve. Another implant structure that appears reasonable to a person skilled in the art would also be feasible, however. 
         [0010]    Moreover, the implant structure comprising a valve implant skirt and/or at least one leaflet, which is/are constructed of porcine, bovine, equine and/or other mammalian tissue and/or synthetic material as polyester, PTFE and/or any other material which is feasible for a person skilled in the art. It is a further object of the present invention to provide a valve implant and/or prosthesis that can be implanted trans-femoral, trans-subclavian, trans-apical and/or with any other implantation way, that appears practical to a person skilled in the art. Further, it is possible to use open surgery, minimally invasive techniques percutaneous, and/or associations thereof. Preferably the valve implant is percutaneously-deliverable. Furthermore, it is advantageous to provide a valve implant, especially with a self-expanding stent design, which is manufactured from one piece without joining of different parts that have e.g. three poles with holes for reinforcing the suture of the valve commissural and define geometrically the three leaflets valve design. 
         [0011]    Furthermore, a “base body” in this context is intended to mean, in particular, a structure such as a wire mesh that substantially imparts a shape and/or form to the valve implant or, in particular, imparts a shape to the stent, or forms the stent itself. In addition, the base body is preferably composed of an elastic or superelastic material such as a metallic material and/or a combination of a plurality of metallic materials, such as iron, magnesium, nickel, tungsten, titanium, zirconium, niobium, tantalum, zinc, silicon, lithium, sodium, potassium, manganese, and/or any other material that appears reasonable to a person skilled in the art. Another possibility would be a zinc-calcium alloy and/or a material having a memory effect, such as a copper-zinc-aluminum alloy and/or a nickel-titanium alloy, preferably Nitinol. Furthermore, it can be advantageous when the base body includes, at the least, cobalt and/or chromium, preferably in the form of stainless steel and/or a Cr—Ni—Fe steel—preferably the alloy 316 L in this case—or a Co—Cr steel. Using this embodiment, an implant can be provided that has good dilatability and advantageous flexibility combined with high stability. Basically, it would also be feasible, however, for the base body of the valve implant to be composed at least partially of plastic, a ceramic, and/or a biodegradable material. 
         [0012]    Moreover, it is an object of the present invention to provide a valve implant and/or prosthesis that is a self-expanding implant and permits a self-centering at the implantation site and/or a natural valve annulus after its deployment. 
         [0013]    Furthermore, a “collar” in this context is intended to mean a substantially circular structure in particular, which is composed of a netlike or mesh-like wire mesh that extends in a circumferential direction of the stent and in an axial extension of the implant, and is composed largely of similar, recurrent elements or cells of a first cell structure. The main shape of the valve implant or the stent, respectively, is given by any single cell of the base body plus the cells of the first cell structure. In this context, a “first cell structure” is intended to mean a structure or cell shape in particular that dominates the base body or forms at least 50%, preferably at least 60%, and particularly advantageously at least 70% of the base body. Minimal deviations in the shape, such as a curvature of one side of the cell, do not prevent cells from belonging to the cells in the first cell structure. These cells can have any shape that appears suitable to a person skilled in the art, such as round, oval, triangular, rectangular, and/or diamond-shaped. The collar and, therefore, the first cell structure, are used in particular to stabilize the implant or the stent, and to ensure that a radial force of the expanded stent or base body is transferred evenly to an implantation site such as an aortic wall. 
         [0014]    In this context, an “intended end state” is intended to mean, in particular, an implanted state of the valve implant in an implantation site such as a site of a defective heart valve. In that case, the implant or the stent is expanded, and is anchored in the correct position at the implantation site. Furthermore, “provided” is intended to mean specially equipped and/or designed. 
         [0015]    In this case, an “intended inner cross section of the base body” defines, in particular, an inner cross section of the base body that forms in the implanted state of the stent due to the expansion of the base body or the stent during implantation. The inner cross section of the base body is advantageously a surface of a rotationally symmetrical, preferably round opening that is adapted to an intended outer cross section of the implantation structure or valve, wherein an “intended outer cross section of the implant structure” in this context is intended to mean, in particular, a surface, particularly a circular surface having a maximum extension of the implant in the implanted state substantially perpendicular to a flow direction of a flow medium such as blood. As a result, the implant structure or the valve is accommodated or can be accommodated in the inner cross section with an exact fit. 
         [0016]    Furthermore, a “second cell structure” refers, in particular, to a cell structure that deviates from the first cell structure in at least one parameter, such as shape, size, dimension, elasticity, number, and/or another parameter that appears reasonable to a person skilled in the art. Cells in this cell structure can have any shape that appears suitable to a person skilled in the art, such as round, oval, triangular, rectangular, and/or diamond-shaped. At least a portion of the second cell structure is connected to the first cell structure and moves therewith when the valve implant or stent expands. 
         [0017]    In this context “movable” is intended to mean, in particular, radially movable and, particularly advantageously, radially movable in the direction of a wall of a blood vessel such as an aortic wall. Preferably, the second cell structure has a lower radial force than a radial force of the first cell structure or the base body, and is preloaded to assume a larger radius than the base body, whereby, in this context, “radial force” is intended to mean, in particular, a force having a vector in the direction of a geometric center or the circle center point of the base body. As a result, when the stent is implanted and therefore expanded, the second cell structure has a greater capability than the first cell structure to move radially outwardly i.e. in the direction of the wall of the blood vessel. The second cell structure or at least a portion of the second cell structure can therefore be moved independently of the first cell structure. This radial difference is independent of a resistance that acts from the outside, such as the force of the wall of the blood vessel (aorta). 
         [0018]    Furthermore, a “contact point” refers, in particular, to a point at which at least a portion of the second cell structure has direct contact with the implantation site, such as the annulus and/or a calcification on the annulus or the aortic bulb, after the implantation process. In addition, an “outer contour of the base body” refers to a contour of an outer cross section, wherein the contour is composed of a surface of the first cell structure, which faces the direction of the aortic wall, and the contact points of the first cell structure having e.g. a calcification, and the contact points of the second cell structure with the wall of the blood vessel or the annulus and/or its calcification. Furthermore, the expression “extreme point of the outer contour” refers to a maximum in the extension of the outer cross section, starting from the geometric center of gravity of the base body in the direction of the wall of the blood vessel, whereby the “geometric center of gravity of the base body” refers, in particular, to a center point and, particularly advantageously, a circle center point of the base body. 
         [0019]    It is therefore advantageously possible to adjust a variable outer contour of the collar or stent in the implanted state using the second cell structure. Furthermore, the embodiment according to the invention provides a medical valve implant that is tailored to the parameters or anatomical details of the implantation site, such as a calcification of the blood vessel wall and/or the annulus, and/or another, congenital and/or diseased anomaly of the implantation site. Furthermore, a pressure gradient of the flow medium acting on the medical valve implant can be kept homogeneous, which advantageously results in a minimal material load on the stent and, therefore, in a minimal risk of fatigue, in the case of Nitinol stents in particular, since the stent opens in a uniform manner. This, in turn, results in a long service life of the cusp and, therefore, the valve. Furthermore, better clinical results compared to conventional valve implants can be achieved by the improved functionality of the valve that can therefore withstand a higher pressure gradient in the presence of an asymmetrically calcified annulus. Furthermore, due to the embodiment according to the invention, the symmetry in the flow dynamics of the flow medium can be increased, which advantageously reduces the risk of further calcification. 
         [0020]    It is an object of the present invention to provide a percutaneously-deliverable valve implant that with the double cell stent concept manufactured from one piece markedly reduces the delivery profile over known designs. 
         [0021]    Moreover, it is provided that at least a portion of the at least second cell structure can be situated obliquely relative to a flow direction of a flow medium. In this context, “oblique” is intended to mean a deviation from the flow direction of the flow medium by up to 45°. At greater angles, the risk of perforation of the aortic wall increases. In this context, a “portion” refers, in particular, to the portion of the second cell structure that can move or move radially relative to the first cell structure. Advantageously, this portion has the shape of a “V”, whereby, given the oblique configuration, a tip of the V is situated radially further in the direction of the vessel wall than the part that can be moved with the first cell structure. In this context, a “flow direction of a flow medium” refers, in particular, to the scientifically known flow direction of arterial and/or venous blood in the heart and, particularly advantageously in the case of the aortic valve, to the flow of blood from the left ventricle into the aorta. By realizing the variable oblique position, the implant can be advantageously adapted locally to implantation sites that have changed to different extents and/or that deviate from the round shape of the implantation site. 
         [0022]    Advantageously, the at least second cell structure is provided to compensate for a difference in the shape of the inner cross section of the base body and a cross-sectional area of an implantation site. In this context, a “shape of the inner cross section of the base body” refers, in particular, to a largely round or cylindrical shape which enables the cusp of the valve to open and close without complication. A “cross-sectional area of the implantation site” in this context is intended to mean, in particular, a highly asymmetrical or non-circular site, in particular having a calcified aortic stenosis. The second cell structure therefore advantageously adapts the non-uniform shapes of the outer diameter of the valve or the inner cross section of the base body to the cross-sectional area of the implantation site. The cells of the second cell structure have the advantage to adapt to the unknown format and amount of the calcified natural valve varying from its pre shaped form till staying inside the cells of the first cell structure following the shape of the main stent. This variation of the cells of the second cell structure position doesn&#39;t interfere with the main shape of the valve implant or stent, respectively. As a result, an asymmetry of the blood vessel wall or the annulus can be compensated for, and a largely round, symmetrical inner shape of the base body can be retained nevertheless to ensure the required flawless, complication-free function of cusps of the valve. 
         [0023]    Furthermore, it is advantageous when at least two second cell structures are distributed in the circumferential direction along the collar. Preferably, the second cell structures are distributed evenly, and particularly preferably, three second structures are situated 120° apart from each other. In general, however, any other type of distribution and number would be feasible. The embodiment according to the invention allows the outer contour of the base body to be advantageously adapted, at a plurality of sites, to the local details of the implantation site, and can therefore be used in a particularly variable manner. The position of the cusp suspension relative to the cell structures is not relevant to their function and can be selected in accordance with the actual basic conditions. 
         [0024]    In a further embodiment of the invention, the at least second cell structure includes at least one cell group, wherein the at least two cells of one cell group are situated axially one after the other in the flow direction of the flow medium, thereby enabling the outer contour to be adapted to different axially situated details of the implantation site, such as calcifications. This prevents deformation of the base body, which results directly in a rotationally symmetrical or ideal expansion of the stent, which positively affects the function of the cusp in the implanted state. In addition to this effect, the second cell structure likewise results in an anchoring of the implant in the axial direction. 
         [0025]    Moreover, it is additionally provided, that the at least second cell structure includes at least one cell with at least two cells halves which are situated in circumferential direction one behind the other, wherein a homogeneous anchoring in circumferential direction can be advantageously achieved. 
         [0026]    It is furthermore provided that one cell of the cell group or one cell halve of a cell is situated on an inner contour of a cell of at least the first cell structure. In this context, an “inner contour” refers, in particular, to a contour that points toward a center point of the cell. A cell of the second cell structure is therefore smaller than a cell of the first cell structure. In general, the cell of the cell group could also be situated on another cell structure. Using the configuration according to the invention, the second cell structure can be situated on/in the base body stably and in a space-saving manner. 
         [0027]    Furthermore, the cells of the first cell structure can be shaped to facilitate the alignment of the valve prosthesis with the direction of blood flow and to lock the valve implant on the natural valve site improving valve implant fixation on the natural valve annulus. The cells of the second cell structure have the advantage to adapt to the unknown format and amount of the calcified natural valve varying from its pre shaped form till staying inside the cells of the first cell structure following the shape of the main stent. This variation of the cells of the second cell structure position doesn&#39;t interfere with the valve implant or stent, respectively, main shape. 
         [0028]    Further, providing a valve implant with e.g. a self-expanding stent design that incorporates the first and second cell structures different shapes for the cells of the second cell structure and the cells of the first cell structure can be allowed, wherein interference of one over the other cell types can be minimized when implanted on the natural valve site. 
         [0029]    In addition, it is advantageous when a cell of the first and/or second cell structure is substantially diamond-shaped. In this context, the expression “substantially diamond-shaped” is intended to mean, in particular, that shapes that are similar to a diamond or a rhombus, such as a diamond-like shape having rounded corners and/or concave and/or convex sides, can also be referred to as “diamond-shaped”. Due to this shape, a particularly stable base body of the implant can be provided. 
         [0030]    Advantageously, the cells of the first cell structure and the second cell structure are diamond-shaped, thereby making it possible to situate the second cell structure on the inner contour of the first cell structure using a particularly simple design. Particularly advantageously, the shape of the cell is designed such that it has a mirror axis that is oriented parallel to the flow direction of the flow medium. As a result, the implant can be brought into the state of implantation, that is, the folded-together state, particularly easily. 
         [0031]    Furthermore, it can be advantageous for the two cells of a cell group or the two cell halves of a cell to be situated with mirror symmetry relative to each other. This results in axial and/or circumferential anchoring in both possible directions. 
         [0032]    A good fixation of the valve and a particularly advantageously stable base body can be achieved when the base body includes a fastening device that is situated between two at least second cell structures and is provided to fix the implant structure in position and stabilize the base body. The fastening device is preferably situated in the center between two second cell structures. 
         [0033]    It is also provided that, in the intended end state, the at least second cell structure is situated axially behind an annulus in the flow direction of the flow medium. The annulus is preferably the aortic annulus. The second cell structure can therefore adapt to irregularly calcified aortic cusps. 
         [0034]    Particularly advantageously, the medical valve implant is designed as an aortic valve, thereby making it possible to provide a refined replacement structure for the heart valve that malfunctions most often. Favorably, complications such as disruptions of the mitral valve or the need for a cardiac pacemaker can also be reduced. An embodiment as a pulmonary valve or an embodiment as a mitral valve is likewise feasible. 
         [0035]    Advantageously, a deposit-inhibiting, in particular calcification-inhibiting, coating can be provided on the valve implant, in particular homocysteinic acid. The risk of a disruption or malfunction of the valve implant can therefore be reduced. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0036]    The invention is explained in the following in greater detail, as an example, with reference to an embodiment depicted in drawings. They show: 
           [0037]      FIG. 1  a medical valve implant according to the invention, in a perspective view, 
           [0038]      FIG. 2  the valve implant according to  FIG. 1 , in the implanted state, 
           [0039]      FIG. 3A  a section III-III through the aortic wall including the implanted valve implant according to  FIG. 2 , 
           [0040]      FIG. 3B  a detailed depiction of the outer contour depicted in  FIG. 3   a,    
           [0041]      FIG. 4  a schematic depiction of the insertion of an aortic valve implant at an implantation site and 
           [0042]      FIG. 5  an alternative embodiment of a valve implant in a perspective view. 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    Elements that are functionally identical or similar-acting are labeled using the same reference numerals in the figures. The figures are schematic depictions of the invention. They do not depict specific parameters of the invention. Furthermore, the figures merely show typical embodiments of the invention and should not limit the invention to the embodiments shown. 
         [0044]    Regarding elements in a figure that are not described further, reference is made to the respective description of the elements in preceding figures to avoid unnecessary repetition. 
         [0045]      FIG. 1  shows, in a perspective view, a medical valve implant  10   a  for implantation in an animal body and/or human body, having a base body  12   a  which comprises a self-expanding stent  64   a  and contains an elastic and/or superelastic and/or self-expanding material, in particular Nitinol. Valve implant  10   a  is furthermore an aortic implant in which an implant structure  22   a  is fastened to base body  12   a  or stent  64   a , implant structure  22   a  being designed as an artificial percutaneous aortic valve  66   a.    
         [0046]    Base body  12   a  comprises a wire mesh as the base body structure, the wire mesh being formed by a collar  16   a  that extends in circumferential direction  14   a  of valve implant  10   a . Collar  16   a  has a first cell structure  18   a  composed of a large number of cells  58   a . Cells  58   a  are substantially diamond-shaped and are situated next to each other in circumferential direction  14   a , and in three rows  70   a ,  72   a ,  74   a  in axial direction. Rows  70   a ,  72   a ,  74   a  are offset in circumferential direction  14   a  such that—referring to rows  70   a  and  72   a  as examples—an upper half  76   a , in each case, of a cell  58   a  of a row  72   a  is fitted into an intermediate space  78   a  between two lower halves  80   a  of cells  58   a  in row  70   a . Cells  58   a  in rows  70   a  and  74   a  are situated axially one above the other. First cell structure  18   a  is provided to form, in the intended end state i.e. the implanted state of valve implant  10   a , an intended inner cross section  24   a  of base body  12   a  that is matched to an intended outer cross section  20   a  of implant structure  22   a  (see  FIG. 3 a   ). 
         [0047]    In addition, a further row  82   a  of end cells  84   a  adjoin first cell structure  18   a  of collar  16   a , in the same manner as described for rows  70   a  and  72   a ; the diamond shape of row  82   a  includes an extended end section  86   a  that extends against a flow direction  42   a  of a flow medium  44   a  such as blood. Furthermore, end section  86   a  bulges in a curved shape outwardly in radial direction  68   a , toward a wall  88   a  of a blood vessel  90   a  such as aorta  92   a  in the implanted state, and therefore valve implant  10   a  has a larger diameter in end region  94   a  than in the region of collar  16   a.    
         [0048]    Furthermore, collar  16   a  or base body  12   a  of valve implant  10   a  or stent  64   a  includes further or three second cell structures  26   a ,  28   a ,  30   a . Second cell structures  26   a ,  28   a ,  30   a  are distributed in circumferential direction  14   a  along collar  16   a , or they are distributed evenly at 120° intervals. Each second cell structure  26   a ,  28   a ,  30   a  includes a cell group  50   a ,  52   a ,  54   a , each of which includes two cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″. Cells  50   a ′,  52   a ′,  54   a ′ are located in row  70   a  and cells  50   a ″,  52   a ″,  54   a ″ are located in row  74   a . Each of the two cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″ belonging to one cell group  50   a ,  52   a ,  54   a  are situated, in the implanted state of valve implant  10   a , axially one behind the other in flow direction  42   a  of flow medium  44   a , that is, from left ventricle  96   a  to aorta  92   a , and with mirror symmetry relative to each other. 
         [0049]    Each of the cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″ of cell group  50   a ,  52   a ,  54   a  is substantially diamond-shaped and is situated on an inner contour  56   a  of a cell  58   a  of first cell structure  18   a . Therefore, cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″ are smaller than cells  58   a . In addition, each of the cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″ has a portion  98   a  that is composed of two sides  100   a  of the diamond and is connected via three fastening points  102   a  to cell  58   a . When stent  64   a  expands, portion  98   a  moves in dependence of stent  64   a.    
         [0050]    A fastening point is not provided on the tip of the “V” on a further portion  40   a  of cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″ which are composed of two further sides  104   a  of the diamond that form the “V”, and is therefore movable independently of the first cell structure  18   a , thereby enabling second cell structure  26   a ,  28   a ,  30   a  to move relative to first cell structure  18   a  or enabling it to move in radial direction  68   a . Portion  40   a  of second cell structure  26   a ,  28   a ,  30   a  can therefore be situated obliquely relative to flow direction  42   a  of flow medium  44   a . In the absence of resistance to portion  40   a , portions  40   a ,  98   a  of cells  50   a ′,  50   a ″,  52   a ′,  52   a ″,  54   a ′,  54   a ″ can therefore assume an angled orientation relative to each other. 
         [0051]    Base body  12   a  furthermore includes three fastening devices  60   a , each having the shape of a segment  108   a  having fastening holes  110   a , to which implant structure  22   a  or aortic valve  66   a  is fastened. Segment  108   a  is an axial extension, which extends in flow direction  42   a , on a cell  58   a  of row  72   a  of collar  16   a . In addition, cell  58   a  is equipped with a reinforcement  112   a  on its inner contour  56   a . End cell  84   a , which is located at the same height, likewise includes a reinforcement  112   a  and an attachment  114   a  that extends against flow direction  42   a . By way of reinforcements  112   a , fastening devices  60   a  contribute to the stability of base body  12   a . Attachment  114   a  is used to connect base body  12   a  to a catheter in the implantation procedure in case of a transapical implantation, where the catheter is inserted from below or from the tip of the heart, respectively (not shown). 
         [0052]    Each fastening device  60   a  is situated in circumferential direction  14   a  in the center between two second cell structures  26   a ,  28   a ,  30   a , and therefore one cusp tip  116   a  of a cusp  118   a  of aortic valve  66   a  is situated in circumferential direction  14   a  at a level of second cell structure  26   a ,  28   a ,  30   a . The three cusp suspensions are located at the level of segment  108   a , the lower edge of cusp  118   a  being located approximately at cusp tip  106   a . Cusps  118   a  are therefore not planar, but rather form a three-dimensional, pyramid-shaped structure. Holding devices  120   a  of base body  12   a  or stent  64   a  for a catheter  122   a  for inserting valve implant  10   a  are situated in circumferential direction  14   a , and extend in flow direction  42   a , at the level of second cell structure  26   a ,  28   a ,  30   a  on cell  58   a  that has contour  56   a.    
         [0053]    Cusps  118   a  of valve implant  10   a  can be provided with a coating to prevent a deposition of calcium salts and, therefore, to prevent calcification of new cusps  118   a.    
         [0054]      FIG. 2  shows a schematic view of medical valve implant  10   a  in the implanted state, e.g. in an annulus  62   a  of a natural aortic valve, that is disposed in blood vessel  90   a , which is aorta  92   a  in this case, in front of left ventricle  96   a  of the heart. End region  94   a , including end section  86   a  of end cells  84   a , which extends further radially outwardly, is situated in front of annulus  62   a  in flow direction  42   a , thereby fixing the broader diameter of end region  94   a  of stent  64   a  in position. Furthermore, in the intended end state, second cell structures  26   a ,  28   a ,  30   a  are situated axially behind an annulus  62   a , e.g. at the level of an aortic bulb  124   a , in flow direction  42   a  of flow medium  44   a , which is indicated only schematically and in regions in  FIG. 2 . 
         [0055]    When the stent  64   a  is implanted, base body  12   a  presses the natural aortic valve (see  FIG. 4 ) against a luminal wall  88   a  of blood vessel  90   a , thereby creating open space for implantation structure  22   a  or artificial aortic valve  66   a  including cusps  118   a  in the inner region of base body  12 . Natural cusps  118   a  are pressed upwardly against the vessel wall  88   a . Cusps  118   a  function as non-return valves and permit blood to flow from ventricle  96   a  to blood vessel  90   a , but block the flow of blood in the opposite direction. 
         [0056]    When valve implant  10   a  expands, first cell structure  18   a  expands, thereby causing end cells  84   a  of end region  94   a  to come in contact with wall  88   a  and fix valve implant  10   a  in position. A further fixation takes place at two uncalcified regions  126   a  of the aortic wall in aortic bulb  124   a  by second cell structure  26   a ,  28   a  or portion  40   a  of cells  50   a ″,  52   a ″ which can move independently of first cell structure  18   a  further radially outwardly than first cell structure  18   a  (structures  26   a  and  50   a ″ are shown only in  FIG. 3 a   , in which cells  50   a ′,  52   a ′ and  54   a ′ were left out to ensure clarity). On a calcified region  128   a  in aortic bulb  124   a , second cell structure  30   a  expands (indicated schematically in  FIG. 3 a   ) only as far as first cell structure  18   a  since a further expansion of second cell structure  30   a  or portion  40   a  is prevented by a calcification  130   a  in aortic bulb  124   a.    
         [0057]    As shown in  FIG. 3A , which shows a section through wall  88   a  of aorta  92   a  with implanted valve implant  10   a  according to  FIG. 2 , second cell structures  26   a ,  28   a  each have one contact point  32   a . Contact points  32   a  form outer contour  34   a  of base body  12   a  together with a surface  132   a , which faces the direction of wall  88   a , of first cell structure  18   a , and of first and second cell structure  18   a ,  30   a , which adjoin calcification  130   a . Outer contour  34   a  is shown alone in  FIG. 3 b    for clarity. As shown in  FIG. 3 b   , contact points  32   a  form extreme points  36   a  of outer contour  34   a  relative to a geometric center of gravity  38   a  of base body  12   a . Second cell structures  26   a ,  28   a  are therefore provided to compensate for a difference in a shape or, in this case, the circular shape of inner cross section  24   a  of base body  12   a  and a cross-sectional area  46   a  of an implantation site  48   a.    
         [0058]    The insertion of medical valve implant  10   a  is illustrated schematically in a partial sectional view, in  FIG. 4 . Valve implant  10   a  is moved, in a compressed state, on a tip  134   a  of catheter  122   a  through the aorta  92   a  in a manner known per se to implantation site  48   a  e.g. annulus  62   a  of the natural aortic valve having cusps  118   a . In this case, an implantation direction  136   a  is opposite flow direction  42   a . Attachment  114  has no function in the event of this implantation direction  136   a.    
         [0059]    In  FIG. 5  an alternative embodiment of the medical valve implant  10   a  is shown. Components, features and functions that remain identical are in principle substantially denoted by the same reference characters. To distinguish between the two embodiments, however, the letters a and b have been added to the reference characters of the embodiments. The following description is confined substantially to the differences from the embodiment in  FIGS. 1 to 4 , wherein with regard to components, features and functions that remain identical reference may be made to the description of the embodiment in  FIGS. 1 to 4 . 
         [0060]      FIG. 5  shows, in a perspective view, a medical valve implant  10   b  for implantation in an animal body and/or human body, having a base body  12   b  which comprises a self-expanding stent  64   b  and contains an elastic and/or superelastic and/or self-expanding material, in particular Nitinol. Valve implant  10   b  is furthermore an aortic implant in which an implant structure  22   b  is fastened to base body  12   b  or stent  64   b , implant structure  22   b  being designed as an artificial percutaneous aortic valve  66   b.    
         [0061]    Base body  12   b  comprises a wire mesh as the base body structure, the wire mesh being formed by a collar  16   b  that extends in circumferential direction  14   b  of valve implant  10   b . Collar  16  has a first cell structure  18   b  composed of a large number of cells  58   b . Cells  58   b  are substantially diamond-shaped and are situated next to each other in circumferential direction  14   b , and in three rows  70   b ,  72   b ,  74   b  in axial direction, wherein an upper half  76   b , in each case, of a cell  58   b  of a row  72   b  is fitted into an intermediate space  78   b  between two lower halves  80   b  of cells  58   b  in row  70   b . Cells  58   b  in rows  70   b  and  74   b  are situated axially one above the other. First cell structure  18   b  is provided to form, in the intended end state i.e. the implanted state of valve implant  10   b , an intended inner cross section of base body  12   b  that is matched to an intended outer cross section of implant structure  22   b  (not shown, analogous to  FIG. 3 a   ). 
         [0062]    In addition, a further row  82   b  of diamond shaped end cells  84   b  adjoin first cell structure  18   b  of collar  16   b  as described above and includes an extended end section  86   b  that extends against a flow direction  42   b  of a here not shown flow medium such as blood and bulges in a curved shape outwardly in radial direction  68   b , toward a wall of a blood vessel in the implanted state (not shown), and therefore valve implant  10   b  has a larger diameter in end region  94   b  than in the region of collar  16   b.    
         [0063]    Furthermore, collar  16   b  or base body  12   b  of valve implant  10   b  includes further or three second cell structures  26   b ,  28   b ,  30   b . Second cell structures  26   b ,  28   b ,  30   b  are distributed in circumferential direction  14   b  along collar  16   b , or they are distributed evenly at 120° intervals. Each second cell structure  26   b ,  28   b ,  30   b  includes a cell  50   b ,  52   b ,  54   b , wherein these cells  50   b ,  52   b ,  54   b  are located in row  72   b . Each of the cells  50   b ,  52   b ,  54   b  includes two cell halves  50   b ′,  50   b ″,  52   b ′,  52   b ″,  54   b ′,  54   b ″, wherein each of these two cell halves  50   b ′,  50   b ″,  52   b ′,  52   b ″,  54   b ′,  54   b ″ are situated, in the implanted state of valve implant  10   b  in circumferential direction  14   b  one behind the other and with mirror symmetry relative to each other (cell  52   b  and cell halves  52   b ′,  52   b ″ are not shown, but embodied identical to cells  50   b ,  54   b  or cell halves  50   b ′,  50   b ″,  54   b ′,  54   b ″, respectively). 
         [0064]    Each of the cells  50   b ,  52   b ,  54   b  is substantially diamond-shaped and is situated on an inner contour  56   b  of a cell  58   b  of first cell structure  18   b . Thus, cells  50   b ,  52   b ,  54   b  are smaller than cells  58   b . Additionally, each of the cell halves  50   b ′,  50   b ″,  52   b ′,  52   b ″,  54   b ′,  54   b ″ has a portion  40   b  that is composed of two sides  104   b  of the diamond and that form a “V”. Ends of the sides  104   b  are each connected via a fastening point  102   b  to cell  58   b . A fastening point is not provided on the tip of the “V” and therefore the portion  40   b  is movable independently of the first cell structure  18   b , thereby enabling second cell structure  26   b ,  28   b ,  30   b  to move relative to first cell structure  18   b  or enabling it to move in radial direction  68   b . Portion  40   b  of second cell structure  26   b ,  28   b ,  30   b  can therefore be situated obliquely relative to flow direction  42   b  of the flow medium. In the absence of resistance to portion  40   b , portions  40   b , of cells  50   b ,  52   b ,  54   b  can therefore assume an angled orientation relative cells  58   b.    
         [0065]    Base body  12   b  furthermore includes three fastening devices  60   b , wherein each fastening device  60   b  is situated in circumferential direction  14   b  between two second cell structures  26   b ,  28   b ,  30   b . The fastening devices have a segment  108   b  extending from a cell  58   b  of row  72   b  and fastening holes  110   b , to which the aortic valve  66   b  is fastened. Cell  58   b  and end cell  84   b , which is located at the same height as cell  58   b  are equipped with a reinforcement  112  on their inner contour  56   b . End cell  84   b  has an attachment  114   b  to connect base body  12   b  to a catheter in the implantation procedure. Holding devices  120   b  of base body  12   b  for a catheter for inserting valve implant  10   b  are situated in circumferential direction  14   b , and extend in flow direction  42   b.    
         [0066]    In the case of the here not shown implantation of the stent  64   b  and thus its expansion the cells  50   b ,  52   b ,  54   b  or the portion  40   b  of each cell  50   b ,  52   b ,  54   b , respectively, has/have the ability to adapt to an unknown format or a cross sectional area of an implantation site in respect to an amount of a calcification at the annulus or the natural valve. This process could vary from its pre shaped form till staying inside the cells  58   b  of the first cell structure  18   b  following the shape of the main stent  64   b  or collar  16   b , respectively. 
         [0067]    It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teaching. The disclosed examples and embodiments are presented for purposes of illustration only. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention.