Patent Publication Number: US-9889003-B2

Title: Transcatheter valve prosthesis

Description:
TECHNICAL FIELD 
     Embodiments generally relate to a transcatheter valve prosthesis, especially a transcatheter atrio-ventricular valve prosthesis. 
     BACKGROUND 
     Heart valve diseases are affecting approximately 300,000 people worldwide each year. Those diseases translate in abnormal leaflet tissue (excess tissue growth, tissue degradation/rupture, tissue hardening/calcifying), or abnormal tissue position through the cardiac cycle (e.g., annular dilation, ventricular reshaping) leading to a degrading valve function like leakage/blood backflow (valve insufficiency) or a resistance to blood forward flow (valve stenosis). 
     Accordingly, a transcatheter valve prosthesis for functional replacement of a heart valve is desirable. 
     SUMMARY 
     Various embodiments of the invention provide a system for implanting a heart valve. The system may include a radially self-expandable tubular body having an inflow end and a preformed groove disposed at an outer surface of the tubular body between the inflow end and the outflow end, wherein the preformed groove extends at least partially around the tubular body and having a circumferential opening facing radially outward of the tubular body. A valve may be disposed within and attached to the tubular body. Additionally, a trapping member may be configured to form at least a partial loop encircling the preformed groove so as to trap portions of native valve leaflets and/or chords in the preformed groove, the trapping member including one or more barbs. 
     Various embodiments of the invention further provide a method for implanting a replacement valve in a patient&#39;s heart. The method may include at least partially deploying from a delivery catheter a radially self-expandable tubular body having an inflow end and an outflow end, a valve disposed within a lumen of the tubular body, and a preformed groove disposed at an outer surface of the tubular body between the inflow end and the outflow end, the preformed groove having a circumferential opening facing radially outward of the tubular body. Additionally, the method may include advancing a trapping member to form at least a partial loop encircling the preformed groove and trapping portions of native valve leaflets and/or chords in the preformed groove, and at least partially piercing the portions of native valve leaflets and/or chords with one or more barbs on the trapping member to secure the tubular body to the portions of native valve leaflets and/or chords. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments are described with reference to the following drawings, in which: 
         FIG. 1  shows schematically a transcatheter valve prosthesis according to embodiments, located in a connection channel of a human heart, 
         FIG. 1 a    shows a detail of a free end of a projection of the valve prosthesis according to embodiments, 
         FIG. 1 b    shows a detail of a free end of a projection of the valve prosthesis according to embodiments, 
         FIG. 2  shows a transcatheter valve prosthesis according to embodiments, 
         FIG. 2 a    schematically shows extension angles of projections according to embodiments, 
         FIG. 3  shows schematically a transcatheter valve prosthesis comprising an elongate outer member according to embodiments located in a connection channel of a human heart, 
         FIG. 4  shows a transcatheter valve prosthesis including a clamping member according to embodiments, 
         FIG. 5  shows the transcatheter valve prosthesis including the clamping member of  FIG. 4  from a different perspective, 
         FIG. 6 a    shows a schematic cross section of a transcatheter valve prosthesis along A-A in  FIG. 3 , 
         FIG. 6 b    shows a schematic cross section of a transcatheter valve prosthesis along B-B in  FIG. 3 , 
         FIG. 6 c    shows a schematic cross section of a transcatheter valve prosthesis along C-C in  FIG. 4  including a clamping member, 
         FIG. 6 d    shows a schematic cross section of a transcatheter valve prosthesis along C-C in  FIG. 4  including a clamping member in another arrangement than shown in  FIG. 6   c.    
         FIG. 7  schematically shows the interaction of a transcatheter valve prosthesis, heart tissue and an elongate outer member according to embodiments, 
         FIG. 8  shows a transcatheter valve prosthesis according to embodiments, 
         FIG. 9 a    shows a tubular body of a transcatheter valve prosthesis, 
         FIG. 9 b    shows a tubular body of a transcatheter valve prosthesis, 
         FIG. 10 a    schematically shows a transcatheter valve prosthesis including an outer member, 
         FIG. 10 b    schematically shows a transcatheter valve prosthesis including an outer member, 
         FIG. 10 c    schematically shows a transcatheter valve prosthesis including an outer member, 
         FIG. 11 a    schematically shows the transcatheter valve prosthesis including an elongate outer member according to embodiments, 
         FIG. 11 b    schematically shows the transcatheter valve prosthesis including an elongate outer member according to embodiments, 
         FIG. 11 c    schematically shows the transcatheter valve prosthesis including an elongate outer member according to embodiments, 
         FIG. 11 d    schematically shows the transcatheter valve prosthesis including an elongate outer member according to embodiments, 
         FIG. 12  schematically shows the transcatheter valve prosthesis according to embodiments, 
         FIGS. 13 a  and 13 b    schematically show the transcatheter valve prosthesis according to embodiments, 
         FIG. 14  schematically shows the transcatheter valve prosthesis according to embodiments, 
         FIGS. 15 a , 15 b , and 15 c    schematically show the transcatheter valve prosthesis and insertion member, 
         FIGS. 16 a  and 16 b    schematically show the transcatheter valve prosthesis according to embodiments, 
         FIGS. 17 a , 17 b , 17 c , 17 d , and 17 e    schematically show the transcatheter valve prosthesis according to embodiments, 
         FIG. 18  schematically shows the transcatheter valve prosthesis according to embodiments, 
         FIG. 19  schematically shows the transcatheter valve prosthesis according to embodiments, 
         FIG. 20  schematically shows the clamping member according to embodiments, 
         FIG. 21  schematically shows the clamping member according to embodiments, 
         FIG. 22  schematically shows the clamping member according to embodiments, 
         FIG. 23  schematically shows the clamping member according to embodiments, 
         FIG. 24  schematically shows the clamping member according to embodiments, 
         FIGS. 25 a , 25 b , and 25 c    schematically show the clamping member according to embodiments, 
         FIG. 26  schematically shows the transcatheter valve prosthesis according to embodiments, and 
         FIG. 27  schematically shows the transcatheter valve prosthesis according to embodiments. 
     
    
    
     DESCRIPTION 
     The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural and logical changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form additional embodiments. 
     With reference to  FIGS. 1, 1   a ,  1   b  and  2 , a transcatheter atrioventricular valve prosthesis  1  for functional replacement of a (native) atrio-ventricular heart valve  5  in a connection channel  10  that connects an atrial heart chamber  15  with a ventricular chamber  20  and comprising a connection channel wall structure  25  may comprise a tubular body  30 . The tubular body  30  may be disposed in the interior of the connection channel  10  and extend along an axis  35 . The axis  35  may be the longitudinal axis  35  of the tubular body  30 , which may be an elongated body. In the implanted condition, the axis  35  of the tubular body  30  may, but need not necessarily, be aligned substantially coaxial to an axis of the connection channel  10 . The tubular body  30  may be radially compressible so as to facilitate approach to and insertion into the connection channel  10 , e.g., using a catheter or the like, and then be radially expandable so as to closely engage the interior or inner side of the connection channel wall structure  25 , and may comprise an artificial heart valve  40  (e.g., schematically shown in  FIG. 6 a   ) arranged within the tubular body  30 . 
     The native atrio-ventricular heart valve  5  (e.g., a mitral valve or a triscupid valve) to be replaced has the generally circumferential wall structure  25  forming the connection channel  10  (or through opening) between the atrial  15  and ventricular  20  chambers of the heart. It includes a circumferential valve annulus, valve leaflets opening the connection channel/through opening and closing the connection channel through opening at a position close to the valve annulus, a generally circumferential chord structure (chordae tendinae) connected between the valve leaflets and generally circumferential papillary muscle(s), and said circumferential papillary muscle(s). 
     The artificial heart valve  40  may be attached to the tubular body  30  and may be designed to serve as an artificial replacement valve for an atrio-ventricular heart valve (for example a mitral and/or a tricuspid valve). The artificial valve  40  may comprise artificial flaps (e.g., three flaps as schematically shown in  FIG. 6 a   ) for functional replacement of the native heart valve. The tubular body  30  may be provided with an outer circumferential groove  45 . The outer circumferential groove  45  may be open to the radial outside of the tubular body  30 . The circumferential groove  45  may define a groove bottom  46 . The outer circumferential groove  45  may define a channel  47  which is defined itself by the groove bottom  46  and axially (in axial direction of the tubular body  30 ) opposite side walls  48 ,  49 . The groove bottom  46  may separate the tubular body  30  into first and second body sections  31 ,  32 . The circumferential groove  45  may extend around a whole circumference of the tubular body  30  or may only extend partially around a circumference of the tubular body  30 . The outer circumferential groove  45  may be a continuous, that is non-interrupted, groove, or may be an interrupted groove  45  having, for example, two or more circumferential groove portions  45  provided, for example, on the same axial level of the tubular body  30  that are interrupted by areas in which no recessed portion, which may provide the groove portion, is formed. The circumferential groove  45  may be located at an axial distance (along axis  35 ) from the axial ends of the tubular body  30 , i.e. the circumferential groove  45  may be spaced apart in an axial direction from end portions of the tubular body  30 . 
     As shown in  FIG. 1 , the first body section  31  may be the part of the tubular body  30  that is located above (e.g., proximal from) the circumferential groove  45 , and the second body section  32  may be the part of the tubular body  30  that is located beneath (e.g., distal from) the circumferential groove  45 . Both of the first and second body sections  31 ,  32  may have a generally cylindrical shape. According to embodiments, the first body section  31  may have a generally conical or expanding shape along the axis of the tubular body, with its cross-section diameter increasing from the groove  45 , and the second body section  32  may be generally cylindrical. According to embodiments, both of the first and second body sections  31 ,  32  may have a conical shape along the axis of the tubular body, with their respective cross-sectional diameters increasing from the groove  45 . Additionally, the outflow end of the tubular body may include a frustoconical shape that slopes radially outward from the preformed groove toward the outflow end when the outflow end, but not the inflow end, has been released from a delivery catheter. 
     According to embodiments, the cross sections (along axis  35 ) of sections  31  and/or  32  may be or contain non-circular shapes such as elliptical or D-shaped cross sections. In addition, the direction of curvature in the axial profile (seen in an axial section along the tubular body  30 ) between the groove  45  and the first body section  31  and/or between the groove  45  and the second body section  32  may change (from concave curvature of the groove  45  to a convex curvature at the transition between groove  45  and first and/or second body section  31 ,  32 ). The axially opposite side walls  48 ,  49  of the groove  45  may be part of the first and second, respectively, body sections  31 ,  32  and may axially delimit the first and second, respectively, sections  31 ,  32  towards the channel  47  of the groove  45 , as it is shown, e.g., in  FIG. 8 . A radial diameter of the first body section  31  (e.g., at an end portion that is opposite to the second body section  32 ) of the tubular body  30  may be larger than any diameter of the second body section  32 . This may allow one to more efficiently fix the prosthesis  1  in the connection channel  10  as the first body section  31  having a larger diameter may provide a better hold of the prosthesis  1  in the connection channel  10  by providing a friction and/or (mere) form fit (e.g., caused by the first body section  31  being located in the atrial chamber  15  and having a diameter larger than a diameter of the connection channel  10 ). 
     As shown in  FIG. 12 , the tubular body  30  may include one or more decorrelation portions  140  configured to dissociate axial and radial movements between an inflow end and an outflow end of the tubular body  30 . For example, the decorrelation portions  140  may dissociate movements between first body section  31  and second body section  32  ( FIG. 1 ). The decorrelation portions may be disposed adjacent to and outside the circumferential groove  45 . As show in  FIG. 12 , the circumferential groove  45  may be disposed between the decorrelation portions  140  and the outflow end of the tubular body  30 , and for example, between the valve  40  and the inflow end. In some embodiments, the decorrelation portions may each include flexible “S” shaped portions or a flexible material, such as polyester fabric. In other embodiments, the decorrelation portions  140  may include a combination of such components. The decorrelation portions are generally configured to stretch or compress in reaction to movement in the outflow or inflow ends. Thus, because the decorrelation portions stretch and/or compress, movement from one end of the tubular body does not translate/communicate to the other end of the tubular body. In this manner, movement in the ends of the tubular body do not correlate with one another. 
     Further, the valve prosthesis  1  may comprise a first plurality of projections  50  and a second plurality of projections  55 . The projections  50 ,  55  may extend from the first and second sections  31 ,  32 , respectively, in opposite axial directions, that is at least with an extension component or an extension vector in a direction along the axis  35  (e.g., the longitudinal axis  35 ) of the tubular body  30 . Accordingly, the first projections  50  and the second projections  55  extend generally towards each other, whereby they may not extend exactly or in line towards each other, but with an extension vector. The projections  50 ,  55  may extend substantially parallel to the axis  35  of the tubular body  30  or may also extend in a (lateral) angle γ to the axis  35  of the tubular body  30 , wherein the (lateral) angle γ extends tangential to the circumference of the tubular body  30 , as it is shown, e.g., in  FIG. 2   a.    
     The valve prosthesis  1  may comprise one plurality of projections  50 ,  55  that may extend from the first or second sections  31 ,  32  in an axial direction of the tubular body  30  and may overlap the circumferential groove  45 . With reference to, e.g.,  FIGS. 11 a - c   , the valve prosthesis  1  may not comprise any projections  50 ,  55 , and the circumferential groove  45  may be provided with (e.g., integrally formed on) the tubular body  30 . 
     The projections of the first plurality of projections  50  each may have a first end  67  and a second end  69  ( FIGS. 13 a  and 13 b   ). The first end  67  may be connected to the tubular body  30  and the second end  69  may form a free end unattached to the tubular body  30 . For example, the first plurality of projections  50  may include free ends  60  and the second plurality of projections  55  may include free ends  65  ( FIG. 1 ). The free ends  60 ,  65  of the first and second pluralities of projections  50 ,  55  may be arranged so as to overlap the outer circumferential groove  45 . That is, the free ends of the first and second pluralities of projections  50 ,  55  are arranged at an axial level of the groove  45  so as to overlap the groove  45 . The first and second pluralities of projections  50 ,  55  as such may at least partially or completely overlap the groove  45  along their extension. 
     The first  50  and second  55  pluralities of projections may extend in a radial distance radially outwards of the bottom  46  of the groove  45  so that a hollow (circumferential) chamber  66  is defined between the groove bottom  46  and the first and second pluralities of projections  50 ,  55  in the channel  47 . The opposite side walls  48 ,  49  may further define the hollow chamber  66  in the axial direction of the tubular body  30 . Hence, the hollow chamber  66  may be confined radially by the pluralities of projections  50 ,  55  and the groove bottom  46  and axially by opposite sidewalls  48 ,  49  (e.g., top- and bottom-walls) of the groove  45 . 
     In embodiments, the second ends  69  of projections  50 ,  55  may include barbs configured to penetrate tissue ( FIG. 1 a   ). In other embodiments, the second ends  69  may include blunt ends configured not to penetrate tissue, for example substantially flat ends  166  extending in a direction substantially parallel to a tangent T of the tubular body  30  ( FIGS. 13 a  and 13 b   ), or a plurality of struts  110  forming rounded (e.g., rounded corner triangle) configurations ( FIG. 14 ). In yet additional embodiments, some or all of projections  50 ,  55  may include barbs, blunt ends, and/or rounded configurations. Transcatheter valve prosthesis  1  may include, in embodiments, the first plurality of projections  50  and/or the second plurality of projections  55 . In these embodiments the first plurality of projections  50  or the second plurality of projections  55  may extend a sufficient distance so that the hollow chamber  66  is defined between the groove  45  and the first plurality of projections  50  and/or the second plurality of projections  55 . Alternatively or additionally, the first plurality of projections  50  and/or the second plurality of projections  55  may define the circumferential groove  45  between the tubular body  30  and the projections  50  and/or  55 , e.g., without indenting of the tubular body. For example, as shown in  FIGS. 16 b    and  19 , circumferential groove  45  is defined between the tubular body  30  and the second plurality of projections  55 . A method of using a transcatheter valve prosthesis  1  may comprise positioning it in the connection channel wall structure  25  of a heart and then inserting tissue that is adjacent to the circumferential groove  45 , of the connection channel wall structure  25  into the circumferential groove  45 , for example to be placed radially below the first and second plurality of projections  50 ,  55 . The tissue can then be held in place in the circumferential groove  45 , for example by the first  50  and/or second plurality of projections  55 , which, if, for example, provided with acute or sharpened ends, may penetrate into the tissue which from its position below may be biased back to its initial radial position. The prosthesis  1  may be positioned such that its outer circumferential groove  45  is at the level of the annulus of the circumferential wall structure  25  or adjacent thereto towards the side of the ventricular chamber  20 . By the first and second plurality of projections  50 ,  55  keeping the tissue within the groove  45 , the transcatheter valve prosthesis  1  can be positioned and fixed relative to the heart. Further, since the first and second plurality of projections  50 ,  55  axially extend towards each other, the prosthesis is safely and reliably prevented from being axially pushed out of the connection channel  10  by the pumping activity of the heart. The first  50  and/or the second  55  plurality of projections may keep the tissue of the connection channel wall structure  25  in the circumferential groove  45  by perforating it (e.g., transfixing it, e.g., skewering it) and/or by an interference fit. The tissue that is held in the circumferential groove  45  may also (partially or fully) seal the transcatheter valve prosthesis  1  against the interior of the connection channel  10  so that blood, e.g., pressurized blood, can only flow through the tubular body  30  (and the artificial heart valve  40  therein) but can not bypass the tubular body  30  on its exterior side (i.e., between the exterior of the tubular body  30  and the interior of the connection channel wall structure  25 ). In this respect, the inner and/or outer circumferential surface of the tubular body  30  may additionally be provided with an impermeable layer, for example in the form of a liner  33   b.    
     The prosthesis  1  may be located in the connection channel  10  so that the circumferential groove  45  is located on the ventricular side of the annulus of a natural valve, e.g., having a distance from the natural valve annulus, i.e., the circumferential groove  45  may be a sub-annular circumferential groove and/or the prosthesis  1  may be a sub-annular-prosthesis  1 . The prosthesis  1  may be adapted to be a sub-annular prosthesis. That is, the tubular body  30  may have a transverse dimension (also referred to as diameter herein) at an axial level (with respect to axis  35 ) that is smaller than a transverse dimension of a natural valve annulus, and/or transverse dimension and/or axial lengths of the tubular body may be suitable so that the first body section  31  may be located in an atrial chamber  15  and that the second body section  32  may be located in the connection channel  10  with the groove  45  being located on a ventricular side of the natural valve annulus having a distance to said annulus. 
     Only one circumferential groove  45  as described above may be provided on the tubular body  30 . However, an elongated prosthesis  1  having two or more circumferential grooves  45  may be provided, wherein a respective set of first and second pluralities of projections  50 ,  55  as described above may be arranged and assigned to the respective one of the two or more grooves  45 . The groove  45  or the respective groove may be formed by the first and second body sections  31 ,  32  of the tubular body  30  as such, wherein the projections  50  and/or  55  may or may not be involved in forming the (respective) groove  45  as such. There may also be embodiments (see further below), in which the projections  50  and/or  55  at least partially form the groove  45 , for example on the side of the tubular body  30  that is proximal to the ventricular chamber  20 . 
     The tubular body  30  may comprise or may be a mesh-type body having elongate mesh or grid elements  33  (e.g., stent struts  107  and/or projections) crossing each other at crossings  34 . The mesh elements  33  may be formed from wires or, for example, a laser-cut tube comprising steel and/or a superalloy and/or a shape memory alloy (e.g., nitinol) and/or nickel and/or titanium and/or precious metals (e.g., gold) and/or alloys comprising the aforementioned. The mesh elements  33  may also comprise other alloys or may be made from organic material, e.g., polymers. The mesh elements  33  may, e.g., be made from polyvinylchloride and/or polystyrene and/or polypropylene or another polymer. The tubular body  30  may be from a shape-memory material which expands when experiencing usual body temperature. The tubular body  30  may be self-expandable. The tubular body  30  may also be not self-expandable, but expandable by a balloon or another expansion mechanism. Correspondingly, the tubular body  30  may be compressible to be insertable via the catheter and may then be expandable when appropriately positioned within the connection channel wall structure  25 . The tubular body  30  may comprise the above-mentioned liner  33   b  (c.f.  FIG. 6 a   ) attached to the mesh elements  33  made from the same or made from different materials. The liner  33   b  may be disposed on an interior side or an exterior side of the mesh elements  33  and/or tubular body  30  and may cover the circumference of the tubular body  30  fully or only partially in axial direction  35  and/or in circumferential direction. 
     The circumferential groove  45  of the tubular body  30  and/or the projections of the first and/or the second plurality of projections  50 ,  55  may interact with the connection channel wall structure  25  so as to fix the valve prosthesis  1  with respect to the channel wall structure  25  and the connection channel  10 . Tissue of the channel wall structure  25  may be “caught” in the circumferential groove  45  and be held in place by the free ends  60 ,  65  of the first and/or the second plurality of projections  50 ,  55 , which may serve as hook elements. The tissue of the channel wall structure  25  may be perforated by the free ends  60 ,  65  and thereby held more firmly in the circumferential groove  45  of the tubular body  30 , wherein the tissue may also be held in the groove  45  by an interference and/or clamping fit between the projections  50  and/or  55  (or part thereof) and the tissue of the connection channel wall structure  25 . In order to allow the first and/or second plurality of projections  50 ,  55  to penetrate the tissue of the circumferential connection channel wall structure  25 , which has been forced into the groove, the free ends of a plurality or of each of the first  50  and/or second  55  pluralities of projections may be an acute or sharpened end. The projections of the first and/or second plurality of projections  50 ,  55  each or some thereof may be pins. 
     With further reference to  FIG. 1 b   , the free ends  60 ,  65  of the first and/or the second plurality of projections  50 ,  55  may be conical ends  70  so as to be able to perforate tissue of the connection channel wall structure  25 . According to embodiments, the free ends  60 ,  65  of the first and/or the second plurality of projections  50 ,  55  may also be blunt. The free ends  60 ,  65  and/or the first and/or second plurality of projections  50 ,  55  may be pin-shaped. 
     Some or all of the free ends  60 ,  65  of the projections  50 , 55  may comprise barbs or hooks  71  as shown in  FIG. 1 a   . The hooks  71  may serve to perforate tissue of the connection channel wall structure  25  and prevent the tissue from slipping off the free ends  60 ,  65 . Thereby tissue that is perforated by barbs or hooks  71  disposed on a free end  60 ,  65  is unable to slip from the free end  60 ,  65  resulting in tissue from the heart valve connection channel wall structure  25  being caught even more reliably in the circumferential groove  45 . Some or all of the free ends  60 ,  65  may be blunt or may have conical ends  70  or comprise barbs or hooks  71 . The first  50  or second  55  plurality of projections may comprise different types of free ends  60 ,  65  according to the anatomical conditions, but may also comprise the same type of free ends  60 ,  65 . 
     The free ends  60 ,  65  and/or the first  50  and second pluralities  55  of projections may be arranged in different axial and/or radial positions and orientations with respect to each other. With reference to  FIGS. 1 and 6   a , each projection of the first plurality of projections  50  may have the same circumferential angular distance a (that is an angular distance between two radial directions extending from longitudinal axis  35  of the tubular body  30 ) from each other, i.e. the projections  50  may be equally circumferentially spaced. However, the projections of the first plurality of projections  50  may also have different angular distances a from each other, i.e. be not spaced evenly around a circumference of the tubular body. Although not shown in  FIGS. 6 a - c   , similarly, each projection of the second plurality of projections  55  may have the same angular distance from each other, i.e. be spaced equally around a circumference of the tubular body  30 . However, the projections of the second plurality of projections  55  may also have different circumferential angular distances a from each other, i.e. be not spaced evenly around a circumference of the tubular body. 
     The first plurality of projections  50  may be arranged with respect to the second plurality of projections  55  on the tubular body  30  in a way that each projection of the first plurality of projections  50  is substantially on the same radial level (that is the same radius, e.g., R 2 ) as a projection of the second plurality of projections  55  (as it is shown e.g., in  FIGS. 1 and 3 ). On the other hand, some or each of the projections of the first plurality of projections  50  may be arranged on a different radius than a projection of the second plurality of projections  55 , for example such that the first plurality of projections  50  may each be on a same radius, and the second plurality of projections  55  may each be on a same radius. 
     With, for example, reference to  FIGS. 1 and 3 , the first plurality of projections  50  and the second plurality of projections  55  may extend so as to be aligned or coaxial to each other. The first plurality of projections  50  may also not be aligned with the second plurality of projections  55 . For example, the first plurality of projections  50  may themselves extend substantially parallel to each other or may not, and the second plurality of projections  55  may themselves extend substantially parallel to each other or may not. 
     With, for example, reference to  FIGS. 2 and 4 , the first and second pluralities of projections  50 ,  55  may be arranged in circumferential direction in an alternating manner, wherein for example each first projection  50  is circumferentially between two second projections  55  (and the other way round). There may also be other appropriate circumferential arrangement patterns for the first and second pluralities of projections  50 ,  55 , wherein, for example, sets of first projections  50 , of for example one, two, three, four, or more first projections  50 , are arranged between sets of second projections  55 , of, for example, one, two, three, four or more second projections  55 . 
     The number of projections of the first plurality of projections  50  and the number of projections of the second plurality of projections  55  may be, for example, in a range of three to five, or eight to ten, fifteen to twenty, thirty to one hundred or more, or may be any other number. The first plurality of projections  50  may comprise the same number of projections or another number of projections as the second plurality of projections  55  or vice versa. 
     The projections of the first plurality of projections  50  and/or the projections of the second plurality of projections  55  may extend from the tubular body  30  from positions where mesh elements  33  of the tubular body  30  are crossing with each other at the crossings  34 . This may improve the mechanical stability of the interconnection of the tubular body  30  with the projections  50 ,  55 . The projections  50 ,  55  may, e.g., be welded, soldered and/or braided to the tubular body  30 . They may be sutured, bonded or glued to the tubular body  30 . As an alternative or additionally, the projections  50 ,  55  may also be monolithically integrally formed with the tubular body  30 . That is, with reference to, e.g.,  FIGS. 9 a  and 9 b   , the projections  50 , 55  (or any one or both of the pluralities of projections) may be formed by mesh elements  33  that are not connected to another mesh element  33  at a crossing  34  but are projecting from the tubular body  30  (e.g., caused by bending the mesh element  33 ) in a radial and/or axial direction with respect to longitudinal axis  35  so as to form a projection  50 ,  55 . Further, projections  50 ,  55  (e.g., monolithically integrally formed by mesh elements  33  or provided separately and connected with the tubular body  30 ) may form the circumferential groove  45  by projecting radially and axially from the tubular body  30  with respect to its longitudinal axis  35 . Accordingly, by facing away from the tubular body  30 , the projections may define a circumferential groove  45  on the tubular body  30 . The circumferential groove  45  may be further defined by a generally conical or similar shape of a body section (e.g., first body section  31  and or second body section  32 ) of the tubular body  30  that has a cross-sectional diameter that is increasing from the groove  45  in a direction of longitudinal axis  35 . As seen e.g., in  FIGS. 9 a  and 9 b   , the generally conical shape of a body section  31 ,  32  may accordingly interact with the projections  50 ,  55  which are projecting from the tubular body  30  so as to further define the circumferential groove  45 .  FIG. 9 a    shows projections  50 ,  55  that define a circumferential groove  45  by projecting first in a substantially radial direction relative to the longitudinal axis  35  and then in a substantially parallel direction to the longitudinal axis  35  when seen from the point from which the projections extend from tubular body  30 .  FIG. 9 b    shows projections  50 ,  55  that extend generally rectilinearly to define the circumferential groove  45 . The projections  50 ,  55  may be made from the same materials that were described above with reference to the tubular body  30 , e.g., super alloys, e.g., shape memory alloys (like nitinol) or steel or titanium (or alloys comprising titanium) or organic material like polymers, or the projections may be made from different material or materials. 
     In embodiments, the first end  67  of the first plurality of projections  50  and/or the second plurality of projections  55  may include one or more first apertures  105  substantially aligned with second apertures disposed between stent struts  107  of the tubular body  30  ( FIGS. 13 a  and 13 b   ). The first apertures  105  may include various configurations including, for example, square, circular, and triangular. Additionally, the first apertures  105  may be larger than, smaller than, or of approximately equal size to the second apertures disposed between the stent struts  107 . The second end  69  of the first plurality of projections and/or the second plurality of projections  55  may also include a match circumferential curvature of stent surface that does not include an aperture. In the embodiment of  FIGS. 13 a  and 13 b   , the second ends  69  form substantially flat ends  166  and extend in a direction parallel to a tangent of the tubular body  30 , and therefore second ends  69  are configured so as not to cause trauma to the surrounding tissue (e.g., Tangent T, as indicated on  FIGS. 13 a  and 13 b   ). 
     As discussed above, in embodiments, the first plurality of projections  50  and/or the second plurality of projections  55  may include blunt ends configured not to penetrate the tissue. For example, the struts  110  may each include a first strut  113  and a second strut  115  joined through connector  117 . As shown in  FIG. 14 , for example, the first struts  113 , the second struts  115 , and the connector  117  together may form rounded triangle configurations. In alternate embodiments, the struts  110  may comprise various configurations, for example, rectangular, rounded, elliptical, or a combination of these configurations, for example, the planar projection shown in  FIGS. 13 a  and 13 b   . In the embodiment of  FIGS. 13 a  and 13 b   , for example, each connector  17  forms substantially flat end  166 . Additionally, the struts  110  may include asymmetrical and/or irregular configurations. For example, as shown in  FIG. 19 , first struts  113  may not be symmetrical with second struts  115  such that the first and second struts  113 ,  115  each include random and different configurations. Furthermore, each connector  117  may include an irregular shape. In some embodiments, each first strut  113  may have a configuration similar to the other first struts  113 , each second strut  117  may have a configuration similar to the other second struts  117 , and each connector  117  may have a configuration similar to the other connectors  117 , but each first strut  113  may have a configuration different from each second strut  115 . 
     As can be seen e.g., from  FIG. 8 , all or some projections of the first plurality of projections  50  and/or all or some projections of the second plurality of projections  55  may extend in (e.g., along) a substantially straight line or in a straight line, i.e., they may not comprise any longitudinal curvature from the point from which they extend from the tubular body  30  to their respective free end  60 ,  65 ; i.e., they may extend rectilinearly. They may, however, nevertheless comprise barbs or hooks  71  and or may be pin-shaped. The first plurality of projections  50  may extend from substantially the same axial level (relating to the axial direction of the tubular body  30 ) from the tubular body  30  (e.g., shown in  FIGS. 1 to 3 ) or may extend from different axial levels from the tubular body  30 . Correspondingly, the second plurality of projections  55  may extend from substantially the same axial level (relating to the axial direction of the tubular body  30 ) from the tubular body  30  (e.g., shown in  FIGS. 1 to 3 ) or may extend from different axial levels from the tubular body  30 . The axial extension of the first plurality of projections  50  (axial distance (along axis  35  of tubular body  30 ) between base of projection on the tubular body and free end of projection) and/or of the second plurality of projections  55  may be substantially the same or may be different, and the extension or length of the first plurality of projections  50  and/or of the second plurality of projections  55  (distance between bases of the projections  50 ,  55  on the tubular body  30  and the free ends  60 ,  65  of the projections  50 ,  55 ) may be the same or may be different. 
     In addition to the first and second plurality of projections  50 ,  55 , the tubular body  30  may be provided with any other type of projection and/or collar. 
     The first  50  and the second  55  pluralities of projections may extend from the first  31  and the second  32  body sections, respectively, from areas that are adjacent to or are bordering the radially outer circumference of the circumferential groove  45 . The first  50  and the second  55  pluralities of projections may extend from the opposite side walls  48 ,  49  laterally defining the groove  45 . 
     Referring to  FIG. 2 , the free ends  60  of the first  50  plurality of projections may be axially spaced from the free ends  65  of the second  55  plurality of projections by an axial distance W 2  in a direction of the axis  35  of the tubular body  30 . The free ends  60  of the first plurality of projections  50  may be arranged on a same axial level or on different axial levels, and the free ends  65  of the second plurality of projections  55  may be arranged on a same axial level or on different axial levels. 
     In case a transcatheter valve prosthesis  1  comprises a plurality of projections  50 ,  55 , the axial distance W 2  may define a distance of one or more or all of the free ends  60 ,  65  of the (one) plurality of projections  50 ,  55  to a sidewall  48 ,  49 , that is opposite to the respective body section  31 ,  32  from which the plurality of projections extends, of the circumferential groove  45 . 
     The projections of the first plurality of projections  50  may axially overlap with the projections of the second plurality of projections  55  (not shown), wherein there may be defined an axial overlapping-distance between the free ends  60  of the first plurality of projections  50  and the free ends  65  of the second plurality of projections  55 . Some free ends  60  of the first plurality of projections  50  may be axially spaced from corresponding free ends  65  of the second plurality of projections  55 , while other free ends  60  and  65  may be arranged so as to axially overlap each other. 
     With reference, for example, to  FIG. 2 a   , the projections  50 ,  55  (each) may extend in a manner so as to be radially and inwardly inclined by an angle β, thereby obliquely extending into the outer circumferential groove  45 . The angle β defining the radial and inward inclination of the projections  50 ,  55  with respect to the axis  35  of the tubular body  30  may be an acute angle, for example in a range of equal to or smaller than 45° or equal to or smaller than 30°, or equal to or smaller than 15°. Only a part or number of the first projections  50  and/or only a part or number of the second projections  55  may radially and inwardly inclined as above described. 
       FIG. 6 a   , which corresponds to the cross section along A-A shown in  FIG. 3 , illustrates the interaction of heart valve tissue of the connection channel wall structure  25  and the first plurality of projections  50  (a cross-section transverse the axis  35  and through the second plurality of projections  55  would result in a similar depiction to that shown in  FIG. 6 a   ). The first plurality of projections  50  can be seen perforating tissue of the connection channel wall structure  25  to thereby more reliably prevent it from retracting from the tubular body  30  of the prosthesis  1 , which results in the prosthesis  1  being held more firmly in its intended place. 
     With further reference to  FIG. 3  and  FIG. 6 b   , the transcatheter atrioventricular valve prosthesis  1  may further comprise an elongate outer member  75 . The elongate outer member  75  may be disposed at the exterior of the connection channel wall structure  25  (e.g., in the ventricular chamber  20 ) at an axial level (e.g., with respect to axis  35 ) of the circumferential groove  45  of the tubular body  30 . The elongate outer member  75  may extend at least partially around, for example completely and continuously circumferentially around, the tubular body  30  and may be handled e.g., using a catheter member  90  that is shown schematically in  FIG. 6 b   . A radial distance R 5  between the longitudinal axis  35  and the elongate outer member  75  may be reducible or reduced so that the valve tissue of the connection channel wall structure  25  can be correspondingly at least partially forced into the outer circumferential groove  45  so as to be at least partially located radially below the first and second pluralities of projections  50 ,  55 . The radial distance R 5  may be reducible or reduced so that it is smaller than a radial distance R 4  that is defined between the longitudinal axis  35  of the tubular body  30  and the free ends  60 ,  65  of the projections  50 ,  55  (the free ends  60 ,  65  are not visible in the cross section shown in  FIG. 6 b   , but they are indicated by crosses in  FIG. 6 b   ). Thus, the elongate outer member  75  may be positioned inside the circumference defined by the first and second pluralities of projections  50 ,  55  so that tissue of the connection channel wall structure  25  is or can be located in the circumferential groove  45  between the groove bottom  46  and the first and second projections  50 ,  55 , wherein the elongate outer member  75  itself may be located inside the groove  45  between the groove bottom  46  and the first and second pluralities of projections  50 ,  55 . However, the elongate outer member  75  may also be arranged to force tissue of the connection channel wall structure  25  into the circumferential groove  45  but to remain outside the groove (i.e. R 5  may be larger than R 4  as shown in  FIG. 6 b   ). The catheter member  90 , or another, for example similarly structured catheter device, may be used to handle and position the elongate outer member  75  around an exterior of the circumferential connection channel wall structure  25 . 
     With further reference to  FIGS. 6 b    and  7 , the catheter member  90  may comprise a connector  91 , for example a cutting and clamping member, that can be used to connect free ends of the elongate member  75 , for example to cut the elongate outer member  75  and clamp two ends of it together, so that the elongate member  75  may remain permanently around the tubular body  30  and thereby form a component of the prosthesis  1 . However, the elongate outer member  75  may also merely be an interventional tool, for example as a component of catheter member, and may only be used to radially force the tissue of the connection channel wall structure  25  into the outer groove  45 , and may then be withdrawn or removed from the heart. When the elongate member  75  remains permanently positioned around an outer side of the connection channel wall structure  25 , it may permanently apply a radial and inwardly, axially, or outwardly directed force to the tissue of the connection channel wall structure  25  towards the groove  45 . 
     With reference to  FIGS. 1, 3, 6   b  and  7 , there may be several ways in which heart tissue of the connection channel wall structure  25  is fixed, held and/or caught in the circumferential groove  45 . The tissue may be perforated by the free ends  60 ,  65  of the first and/or the second plurality of projections  50 ,  55 , e.g., via the acute ends  70  and/or the barbs or hooks  71 . The tissue may be held in the circumferential groove  45  by an interference fit between the projections  50 ,  55 . The tissue may also be held in the circumferential groove  45  by the elongate outer member  75 . The elongate outer member  75  may be used to force the tissue into the groove  45  either temporarily (e.g., as a method step during a heart treatment) or permanently (for example, if the cutting and clamping member  91  is used to cut elongate outer member  75  and to connect its two ends together permanently while it is extending around the exterior of the connection channel wall structure  25  as shown in  FIG. 7 ). The tissue of the connection channel wall structure  25  may also be held in the circumferential groove  45  by a combination of two or more of the above described approaches. 
     In embodiments, the elongate outer member  75  may have a cross-sectional diameter D 1  (see e.g.,  FIG. 6 b   ) that is smaller than a width W 1  of the outer circumferential groove  45  (illustrated e.g., in  FIG. 2 ). The elongate member  75  may have a cross-sectional diameter D 1  that is smaller than the gap W 2  between the free ends  60 ,  65  of the first and the second plurality of projections  50 ,  55 . The elongate member  75  may have a cross-sectional diameter D 1  that is larger than width W 2  but smaller than width W 1 . The elongate member  75  may have a cross-sectional diameter D 1  that is larger than width W 2  and/or width W 1 . The elongate member  75  may be a wire or a band, and may have a circular cross section or a rectangular cross section. The elongate member  75  may also have a triangular cross section or a cross section defining any other curved or polygonal shape. The elongate member  75  may be made from any material that has been described with reference to the mesh elements  33  or a combination of those materials or other material(s). For example, the elongate member may be made from steel, a titanium alloy or a shape memory alloy such as nitinol. 
     A length of the projections  50  and/or  55  may be related to the width W 1  of the circumferential groove  45 . In this respect, the ratio of a distance between the free ends  60 ,  65  of the first and second pluralities of projections  50 ,  55  (or, if only one plurality of projections  50 ,  55  is provided, a distance of the free ends  60 ,  65  of that plurality of projections  50 ,  55  to the sidewall  48 ,  49  of the circumferential groove  45  that is with respect to axis  35  opposite to the projections  50 ,  55 ) to the width W 1  of the circumferential groove  45  may have a maximum value of 0.5 or 0.4 or 0.3 or 0.2 or 0.1. Accordingly the hollow chamber  66  may be defined between the projections  50 ,  55  and the groove bottom  46 . The width W 1  of the circumferential groove  45  may be defined between the sidewalls  48 ,  49  of the groove  45  and or between a point from which a projection  50 ,  55  of the first and/or second plurality of projections  50 ,  55  extends from the tubular body  30  and a sidewall  48 ,  49  that is located on an opposite side of the groove ( 45 ) and/or between a point from which a projection from the first plurality of projections  50  extends and a point from which a projection form the second plurality of projections  55  extends. 
     With reference to  FIGS. 4 and 5  (for improved clarity and understanding, the transcatheter valve prosthesis  1  is shown without artificial valve  40 ), the transcatheter valve prosthesis  1  may also comprise a clamping member  80 . The clamping member  80  may comprise a tubular structure having a longitudinal axis that may be arranged so as to extend in the circumferential groove  45  in a circumferential direction of the tubular body  30 . The clamping member  80  may be located in the circumferential groove  45  so as to be located (for example at least partly) radially inwards of the first and second pluralities  50 ,  55  of projections. The clamping member  80  may be in contact with the groove bottom  46  of the circumferential groove  45 . The clamping member  80  may extend around a whole circumference of the tubular body  30  or only partially around the tubular body  30 , as shown, e.g., in  FIGS. 4 and 5 . The clamping member  80  may extend, e.g., around an angle of 10 to 30 degrees or any other angle in the circumferential groove  45 . The clamping member  80  may extend around the whole circumference of groove  45 , e.g., around 360 degrees. The clamping member  80  may have a cross-sectional diameter D 2  transverse to its longitudinal axis. The cross-sectional diameter D 2  may be selectively changeable to a larger or smaller diameter D 2 ; i.e., the clamping member  80  may be compressible (so as to be insertable via a catheter) and/or expandable (for example, re-expandable after being compressed) in a radial direction of its diameter D 2 , whereby the inner and outer circumferences of the clamping member are correspondingly decreased/expanded and expanded/decreased, respectively, in a radial direction of the tubular body  30  towards the first and/or the second plurality of projections  50 ,  55 . The cross sectional diameter D 2  of the clamping member  80  may be smaller than the cross sectional diameter (radius R 1  is shown, e.g., in  FIG. 6 a   ) of the tubular body  30 . In embodiments, the diameter D 2  of the clamping member  80  may be smaller than the width W 1  of the outer circumferential groove  45  and smaller than the width W 2  of the gap formed between the free ends  60 ,  65  of the first and the second plurality of projections  50 ,  55 . The clamping member  80  may be provided in order to clamp heart tissue that is located inside the circumferential groove  45  outwards in a direction from the axis  35  towards the pluralities of projections  50 ,  55 . 
     The clamping member  80  may include a delivery configuration within a delivery catheter and a deployment configuration wherein the clamping member  80  is deployed from the delivery catheter. In embodiments, the clamping member  80  may be biased to the deployment configuration. For example, the clamping member  80  may include a shape-memory alloy such as a nitinol or a nitinol-based alloy that has a delivery configuration that is shaped to be convenient for delivery through a catheter, and a deployment configuration in which the shape-memory alloy changes shape to a deployed configuration so as to be biased to a shape conforming to the tubular body. 
     With reference to  FIG. 6 d   , the clamping member  80  may be or form part of the above-described elongate outer member  75 , wherein the clamping member  80  may be arranged and or guided and/or positioned (in a radially compressed condition) at the circumferential outer side of the connection channel wall structure  25  to completely or partly extend around the connection channel wall structure  25  at an axial (with respect to the axis  35  of the tubular body  30 ) level, and may then be radially expanded (in a direction of the diameter D 2  of the clamping member  80 ), whereby its inner diameter in a radial direction of the tubular member  30  then correspondingly decreases to thereby force the tissue of the inwardly arranged connection channel wall structure  25  (which is then arranged inwards of the clamping member  80 ) radially into the groove  45 . That is, the clamping member may be located between the projections  50 ,  55  and tissue of the connection channel wall structure  25 , that may be pressed into the groove  45  by an elastic force exerted by the clamping member  80  on the tissue of the connection channel wall structure  25  and a corresponding reactive force that may be exerted by the clamping member  80  on the projections  50 ,  55 . The forces that may act upon the tissue of the connection channel wall structure  25  exerted by the clamping member  80  and the groove  45  (e.g., the groove bottom  46 ) are schematically indicated by arrows  85   b . The elongate outer member  75  and/or the clamping member  80  (which may be the same member) may serve to anchor the prosthesis  1  and to seal the native heart leaflets against the prosthesis  1  against blood flow. Further, immobilization of the native leaflets by the prosthesis  1  as described herein (e.g., comprising a clamping member  80  and/or elongate member  75 ) may favor the ingrowth of heart (e.g., leaflet) tissue into the prosthesis (e.g., circumferential groove  45 ) and thereby further improve fixation of the prosthesis  1  relative to the heart and/or sealing against blood flow as the ingrown tissue may additionally or alternatively seal against blood flow on an outside of the tubular body  30 . 
     In some embodiments, the clamping member  80  may include one or more barbs  230  configured to secure the prosthesis  1  to portions of the native valve leaflets and/or chords when the barbs  230  are deployed, for example, by piercing the portions of native valve leaflets and/or barbs. For example, as shown in  FIG. 20 , the clamping member  80  may include an inner member  210  slideably disposed within a hollow outer tube  200 . It is further contemplated that the outer tube  200  may be slideably disposed with regard to the inner member  210 . One or more flexible regions  240  may be disposed on the outer tube  200  to facilitate bending of the clamping member  80 . The flexible regions  240  may include cutouts, for example as shown in  FIG. 20 , or may include material sufficient to facilitate such bending of the clamping member  80 . The cutouts may be of various shape and sizes. Additionally, the flexible regions  240  may be disposed consistently or intermittently on outer tube  200 . 
     One or more openings  220  may be disposed through an outer surface of the outer tube  200 , such that the openings  220  are coupled with one ore barbs  230  on the inner member  210 . For example, the barbs  230  may each be configured to assume a first delivery configuration wherein the barbs  230  are disposed substantially parallel to the inner member  210  and are disposed within the outer tube  200 . For example, the barbs  230  may lay substantially flat along the inner member  210 . Movement of the inner member  210  relative to the outer tube  200  may substantially align the barbs  230  with the openings  220  such that the barbs  230  move from the first delivery configuration to a second deployment configuration. For example, as shown in  FIG. 22 , the barbs  230  may extend away from the clamping member  80 , and may be configured to attach to the native leaflets and/or chords. Therefore, the barbs  230  may be deployed through the openings  220  when in the deployment configuration. 
     Various means may be used to deploy the barbs  230  from their delivery configuration to their deployment configuration. For example, the barbs  230  may be comprised of a superelastic material such that they immediately assume the deployment configuration once aligned with openings  220 . In other embodiments, the barbs  230  may be moved into the deployment configuration through a hydraulic force (for example, by the inflation of a balloon), pushing of the barbs  230 , rotating of the barbs  230 , a spring mechanism, and/or thermal electric current. 
     The barbs  230  may be deployed, and assume the deployment configuration, before the tubular body  30  is fully deployed. For example, the barbs  230  may be deployed when the tubular body  30  is partially deployed. Alternatively, the barbs  230  may be deployed after the tubular body  30  is fully deployed. 
     The delivery configuration of the barbs  230  may be substantially perpendicular to the deployment configuration of the barbs  230 . Additionally, the barbs  230  may be arcuate when in the deployment configuration, for example as shown in  FIGS. 21 and 23 . It is further contemplated that the barbs  230  may constitute a helical structure configured to be driven into the connection channel wall structure  25  when the barb is rotated about its longitudinal axis ( FIG. 27 ). The helical structure may pierce adjacent native leaflets and/or chords (e.g. a first portion and a second portion) to secure the adjacent native leaflets and/or chords together, as shown in  FIG. 27 . The helical structure may include a helical needle. In some embodiments, a suture may be advanced from the helical needle to secure the adjacent native leaflets and/or chords together. 
     In some embodiments, the clamping member  80  may include a first set of barbs  233  configured to be oriented toward an inflow side of the circumferential groove  45  when the clamping member  80  at least partially encircles the circumferential groove  45 , as shown in  FIG. 26 . Additionally or alternatively, the clamping member  80  may include a second set of barbs  235  configured to be oriented toward an outflow side of the circumferential groove  45  when the clamping member  80  at least partially encircles the circumferential groove  45 . 
     The inner member  210  may include one or more slits  250  on an outer surface of the inner member  210 . Each barb  230  may be disposed within a slit  250  when the barb  230  is in the delivery configuration. Therefore, the inner member  210  may be configured to slide within the outer tube  200  without interference from the barbs  230 . Additionally or alternatively, the inner member  210  and/or the outer tube  200  may be coated with a lubricious coating to facilitate the sliding of the inner member  210  relative to the outer tube  200 . 
     A pusher tube  260  may be configured to push and/or pull the inner member  210  in a longitudinal direction of or rotationally relative to the outer tube  200  to deploy the barbs  230 . It is also contemplated that the pusher tube  260  may be configured to push and/or pull the outer tube  200  in a longitudinal direction of or rotationally to the inner member  210  to deploy the barbs  230 . As shown in  FIGS. 25 a -25 c   , for example, the pusher tube  230  may be releasably attached to the inner member  210  through connection  270 . In some embodiments, the connection  270  may include a first connection link  280  on the pusher tube  260  that is releasably coupled to a second connection link  290  on the pusher tube  260 . Therefore, the pusher tube  260  may selectively push and/or pull the clamping member  80  when the first connection link  280  is attached to the second connection link  290  to align the barbs  230  with openings  200  to deploy the barbs  230 . Additionally, the pusher tube  260  may be selectively released from the inner member  210 . In some embodiments, the pusher tube  260  may be advanced over the elongate outer member  75  to deploy the barbs  230 . For example, the pusher tube  260  may be connected to inner member  210  through connection  270  and advanced over the elongate outer member  75  with the clamping member  80 . 
     The barbs  230  may be configured to attach to the projections  50  and/or  55  to secure the prosthesis  1  to the portions of native valve leaflets and/or chords. For example, as shown in  FIGS. 26 and 27 , the first set of barbs  233  may be disposed through projections  55  and the second set of barbs  235  may be disposed through projections  50 . As shown in  FIGS. 26 and 27 , the shape of the barbs  230  secures the barbs  230  to the projections  50 ,  55 . It is further contemplated that other well-known attachment means may be used to secure the barbs  230  to the projections  50 ,  50 , for example, including but not limited to, sutures, adhesive, clamps, etc. 
     The circumferential opening of the groove  45  may be defined by an indent in a side surface of the tubular body  30 , and the groove  45  may be larger than a maximum outer diameter of the clamping member  80 , as shown in  FIGS. 26 and 27 . Therefore, the attachment of the barbs  230  to the portions of native valve leaflets and/or chords may secure the prosthesis  1  to the portions of native valve leaflets and/or chords. Withdrawal of the barbs  230  away from and out of the portions of native leaflets and/or chords may thus cause the prosthesis  1  to no longer be secured to the portions of native valve leaflets and/or chords. 
     In embodiments, when partially deployed, such that the outflow end but not the inflow end is deployed from a delivery catheter, the tubular body  30  may form a frustoconical shape that slopes radially outward from the circumferential groove  45  and toward the outflow end. For example, the tubular body  30  may slope radially outward approximately 2°-45° with regard to a longitudinal center axis of the tubular body  30  when partially deployed. In embodiments, the tubular body  30  may slope approximately 5°-30°, or approximately 10°-20°, or approximately 15° with regard to the longitudinal center axis of the tubular body. 
     In the partially deployed state, the elongate outer member  75  maybe slid along the tubular body  30  to guide tissue of wall structure  25  (e.g., native valve leaflets and/or chords) into the circumferential groove  45 . For example, the elongate outer member  75  may slide in a direction moving radially inward along the slope of the tubular body  30  from an outflow end of the tubular body toward an inflow end of the tubular body  30  and into circumferential groove  45 . When sliding along the frustoconical shape of the partially deployed tubular body  30 , the elongate outer member  75  may be disposed outside the wall structure  25  and therefore slide along the tubular body  30  and along the wall structure  25 . Therefore, elongate outer member  75  may move the native valve leaflets and/or chords of the wall structure  25  into the circumferential groove  45  such that the native valve leaflets and/or chords are disposed between the tubular body  30  and elongate outer member  75  ( FIG. 10 c   ). This may trap the native valve leaflets and/or chords within the circumferential groove  45 . 
       FIG. 6 c    shows a schematic cross sectional view of the tubular body  30  and the clamping member  80  similar to the cross section C-C in  FIG. 4 , however additionally showing heart tissue of the connection channel wall structure  25  that is not shown in  FIG. 4 . In  FIG. 6 c   , the positions of the first or second pluralities of projections  50 ,  55  are indicated by dots  50 ,  55 . As can be seen from  FIG. 6 c   , the heart tissue of the connection channel wall structure  25  is located inside the circumferential groove  45  radially between the groove bottom  46  of the tubular body  30  and a diameter that is defined by the free ends  60 ,  65  of the first and/or the second plurality of projections  50 ,  55 . It can be seen from  FIG. 6 c    that the clamping member  80  is elastically strained by the tissue of the connection channel wall structure  25  and in turn exerts a force that presses the tissue of the connection channel wall structure  25  against the free ends  60 ,  65 . Arrows  85  indicate the forces that are caused by the clamping member  80  and that act upon the tissue of the connection channel wall structure  25  in the groove  45 . 
     With reference, e.g., to  FIGS. 6 c  and 6 d   , which show only one clamping member  80 , there may also, e.g., be two or more clamping members  80  arranged in the groove  45  which are arranged in parallel to each other and/or which are arranged sequentially in a circumferential direction, with for example a circumferential distance therebetween or abutting each other, of the tubular body  30 . For example, there may be two clamping members  80  abutting each other and a third clamping member  80  that has an angular distance from the two clamping members  80  that are abutting each other may also be arranged in the groove  45 . Clamping members  80  may, e.g., be positioned on diametrically opposite sides of the groove  45 . These two or more (e.g., 3 to 5) clamping members  80  may all have the same cross-sectional diameter D 2  or may each have different cross-sectional diameters. The clamping members  80  may all have the same longitudinal length or may have different longitudinal lengths (e.g., in a circumferential direction of tubular body  30 ). Clamping members  80  may be designed and arranged so that the tubular body  30  is firmly held in place according to the specific tissue structure and conditions of the connection channel wall structure  25  of a specific heart (e.g., of a patient). They may, e.g., be specifically chosen and arranged by an operator or surgeon to firmly hold the tubular body  30  in place according to local conditions. The respective clamping member  80  may have a shape other than a tubular shape, such as a block-shape, a cubic-shape or a ball-shape. 
     The force acting on the tissue of the connection channel wall structure  25  may be increased when the clamping member  80  is used together with the elongate outer member  75 , thereby further improving the connection between the transcatheter valve prosthesis  1  and the connection channel wall structure  25 . In this case, an elastic force originating from the clamping member  80  pointing from the axis  35  outwards, and a force originating from the elongate outer member  75  pointing inwards to the axis  35 , act upon tissue of the connection channel wall structure  25 , thereby holding the prosthesis  1  firmly in its intended position in the connection channel  10 . However, the valve prosthesis  1  may be used without the clamping member  80  and the elongate outer member  75  as well (i.e., by itself), or together with only one (any one) of them. A prosthesis  1  not comprising a plurality of projections  50 ,  55  may be fixed by clamping member  80  and/or elongate outer member  75 , e.g., when the elongate outer member  75  and/or the clamping member  80  are/is generally rigid, e.g., when comprising or being an inflatable balloon that is filled with a substance giving it rigidity caused by a pressure or by a curing of that substance. If present, that substance can cure within a limited amount of time, with the injection of an additional agent (e.g., a reticulating agent), with application of heat or energy. It can be, for example, PMMA (Poly Methyl Methacrylate), different epoxies, polyurethane, or a blend of polyurethane silicone. It can be strengthened, for example with the addition of reinforcement fibers (e.g., polyaramid such as Kevlar®, carbon). 
     Clamping member  80  may be made from a mesh-type structure as shown in  FIGS. 4 and 5  and may comprise an inner lumen. The mesh may be made from metal or organic material or other material. The mesh of clamping member  80  may be made, e.g., from iron, nickel, aluminum and/or titanium and/or alloys of these metals and other elements. The mesh may be made, e.g., from steel (e.g., spring steel), and/or a superalloy and/or shape memory alloy (such as, e.g., nitinol), Ti 6 Al 4 V, and/or a precious metal like gold, or any combination of those and/or other materials. The mesh of clamping member  80  may also be made from polymers, e.g., from polypropylene or polyvinylchloride, polyethylene or nylon. Of course, the mesh may also be made from combinations of these materials, i.e., it may be made from two or more different materials. In embodiments, the clamping member can be an expandable stent-graft made with a steel or nitinol stent covered with a polyester or PTE (polyethylene terephthalate) graft material, such as Dacron®, or an ePTFE (expanded Poly Tetra Fluoro Ethylene) graft material. The mesh of clamping member  80  may also or additionally comprise any material that has been described with reference to the mesh elements  33  of the tubular body  30  and/or with reference to the elongate member  75 , and the clamping member  80  may be designed and a material for it may be chosen so as to create a high elastic force to press the tissue of the connection channel wall structure  25  against the projections  50 ,  55 . Clamping member  80  may be provided with hooks or barbs to create an attachment to tubular body  30 . 
     Clamping member  80  and/or elongate outer member  75  may comprise an inflatable inner member (not shown). The inflatable inner member may be disposed in an inner lumen of the clamping member  80  and may be inflated so as to increase diameter D 2  of clamping member  80 , thereby pressing tissue of the connection channel wall structure  25  against the projections  50 ,  55  (either from an inner side if the clamping member  80  is arranged in the hollow chamber  66  or from an outer side if the clamping member  80  is arranged at an outer side of the connection channel wall structure  25 ). The inner member may be inflated by the operator using a tubing and fluid (gas or liquid) from an external pressure source, e.g., a syringe, a fluid bottle or a pump located outside the body. The clamping member  80  may be an inflatable member  80  that presses tissue of the connection channel wall structure  25  against the projections  55 ,  55  when inflated. Both the inflatable inner member and the inflatable member  80  may be made from a fluid tight, pressure resistant material, e.g., a material or polymer as described above with reference to the clamping member  80 , or any other suitable material. With reference to, e.g.,  11   a - 11   b , the inflatable member may comprise an aperture  76  (e.g., a valve, e.g., an opening) through which a substance (e.g., via a delivery tube (not shown)) may be delivered into the inflatable member and/or out of the inflatable member. The aperture  76  may selectively permit the transmission of a substance (i.e., have an “open-state”) or may block the transmission of a substance (i.e., have a “closed-state”). The aperture  76  may serve to fill the inflatable member or to un-fill (e.g., to empty) the inflatable member in order to change a cross-sectional diameter of the inflatable member. The clamping member  80  and/or the elongate outer member  75  may be made of an elastic material (e.g., a polymer and/or a metal) and/or may be filled with a compressible (e.g., elastic) substance (e.g., a gas and/or a foam material and/or a hydrogel) to provide a damping/cushioning functionality. A substance for filling the inflatable member may be a gas, a liquid or any other substance and/or may be a substance that changes its phase (e.g., gas, liquid, solid) when in the inflatable member (the substance may, e.g., change from liquid phase to a generally solid phase). The substance may be a substance that is capable of curing and/or hardening when disposed in the inflatable member so as to provide a generally rigid clamping member  80  and/or elongate outer member  75 . 
     Clamping member  80  may apply a force to the opposite side walls  48 ,  49  of groove  45 , for instance upon radial expansion relative to its longitudinal axis. This force may increase or decrease the distance between body sections  31  and  32  and/or the distance between axial ends (with respect to axis  35 ) of the tubular body  30 . Tubular body  30  may be made to be elastic (e.g., comprising a mesh structure and/or an elastic material). The force exerted by clamping member  80  may result in an expansion or reduction of a perimeter of the groove bottom  46  along a circumference of groove  45  and/or in an expansion or reduction of diameter R 1  of the tubular body  30  at an axial height (with respect to axis  35 ) of groove  45  respectively. The clamping member  80  and/or the elongate outer member  75  (which may be the same member or may be separate members) may also not produce a force in a radial direction and/or a longitudinal direction of the tubular body  30  with respect to its longitudinal axis  35 . Accordingly, the clamping member  80  and/or the elongate outer member  75  may act as a displacement member by displacing tissue of the connection channel  10  without exerting a clamping force to the tubular body  30  but by providing a mere interference fit between the circumferential wall structure  25  of the connection channel  10 , the clamping member  80  and/or the tubular body  30  in addition or as an alternative to, e.g., tissue being pierced by projections of the first  50  and/or second plurality of projections  55 . 
     The clamping member  80  and/or elongate outer member  75  may be located only partially radially inwards of the first  50  and/or second  55  plurality of projections and may be located so as to be pierced by any one or both pluralities of projections  50  so as to be held relative to the tubular body  30 . The elongate outer member  75  and/or clamping member  80  may be pierced by only one plurality of projections  50 ,  55  and the other plurality of projections may not pierce the clamping member  80 /elongate outer member  75  (or, the other plurality of projections may not be provided in case of a prosthesis  1  only comprising one plurality of projections (on one side of the groove  45 )). The plurality of projections  50  and/or  55  may pierce the clamping member  80  so that the respective free ends  60 ,  65  of the projections  50 ,  55  end inside the clamping member  80  or so that the free ends  60 ,  65  of the respective projections  50 ,  55  penetrate through the clamping member  80  and exit from the clamping member so that the respective free ends  60 ,  65  may be located outside the clamping member  80 . 
     With reference to  FIG. 10 b   , the elongate outer member  75  and/or the clamping member  80  may be provided in the groove  45  radially inwards of the projections  50 ,  55  so that the elongate outer member  75  and/or the clamping member  80  is not pierced by the projections  50 ,  55 . In embodiments, the clamping member  80  may trap at least portions of native valve leaflets and/or chords within the circumferential groove  45  defined by the tubular body  30  and the first plurality of projections  50  and/or the second plurality of projections  55 . For example, the native valve leaflets and/or chords may be disposed between the clamping member  80  and the second plurality of projections  55  within circumferential groove  45 . The elongate outer member  75 /clamping member  80  may be held by a mere interference fit or a frictional/interference fit between the groove  45 , the tissue of the connection channel wall structure  25  and or projections  50 ,  55  in the groove  45  (e.g., when inflated, e.g., when expanded). Further, as schematically shown in  FIG. 10 b   , the elongate outer member  75 /clamping member  80  may have a cross sectional shape that is substantially elliptical or has any other shape, such as a triangular, rectangular or polygonal shape. The substantially elliptical shape of the elongate outer member  75 /clamping member  80  that is shown in  FIG. 10 b    may be caused by the design of the elongate outer member  75 /clamping member  80 , e.g., when it is provided with a tubular structure having a substantially elliptical shape (e.g., when expanded), or it may be caused by anisotropic forces acting upon elongate outer member  75 /clamping member  80  caused, e.g., by the projections  50 ,  55 , the tissue of the circumferential wall structure  25  and/or groove  45 . That is, the elongate outer member  75 /clamping member  80  may have a substantially round cross section when no external forces act upon it and may assume a different shape (e.g., elliptical), when implanted (and, e.g., expanded). 
     With reference to, e.g.,  FIG. 10 c   , an expandable and or reducible elongate outer member  75  (e.g., clamping member  80 ) may have a diameter D 2  that may be larger than width W 1  of circumferential groove  45  when expanded so that the elongate outer member  75  may extend out of the groove  45  and may occupy a space between the circumferential wall structure  25  and tissue forming a heart chamber (e.g., the ventricular chamber  20  and/or atrial chamber  15 ), i.e., the elongate outer member  75  may form a shape arranged between (e.g., abutting) the connection channel wall structure  25  and tissue/muscles of a heart chamber wall (e.g., of ventricular chamber  20 ) when expanded (e.g., fully expanded). Accordingly, the elongate outer member  75  may be located (e.g., partially, e.g., a part thereof) radially outside (with respect to axis  35 ) the circumferential groove  45  and may extend parallel to axis  35  along one or both body sections  31 ,  32  (e.g., along second body section  32 ) of tubular body  30  while being (e.g., partially, e.g., a part of elongate outer member  75 ) located radially outside groove  45 . Accordingly, the elongate member  75  may comprise an angularly shaped (e.g., substantially describing an angle of about 90°) cross section with a first angular leg  75   a  that may extend with respect to axis  35  generally radially into the groove  45 , and a second angular leg  75   b  mat may extend generally parallel to axis  35  of the tubular body  30  on an outside of the tubular body  30  (e.g., along first body section  31  and/or second body section  32 ). That is, the elongate outer member  75  (e.g., second angular leg  75   b  thereof) may be disposed between the first  31  and/or second  32  body section and tissue/muscle forming a wall of a heart chamber such as the ventricular chamber  20  and/or atrial chamber  15 . While in  FIG. 10 a - c    the elongate outer member  75 /clamping member  80  is only shown on one side of the prosthesis  1 , it may also extend fully or partially (as shown, e.g., in  FIG. 11 a - d   ) around the prosthesis  1  (e.g., the circumferential groove  45 ). The elongate outer member  75 /clamping member  80  may comprise free ends  77 ,  78  (e.g., two free ends  77 ,  78 ) in a direction of a central-longitudinal axis that may be non-connected and/or not abutting each other, i.e., spaced away from each other. The free ends  77 ,  78  may have an angular distance from each other (e.g., in the groove  45 , e.g., when inflated in the groove  45 ) defined by an angle of, e.g., less than 180°, less than 90°, less than 45° or less than 10° with respect to axis  35 . The aperture  76  may be provided on one of these free ends  77 ,  78  or an aperture  76  may be provided on each of the free ends  77 ,  78 . When the elongate outer member  75 /clamping member  80  only extends partially around circumferential groove  45  and accordingly comprises free ends, it may have a rigidity caused by a substance, e.g., by a curing substance (that may be cured). 
     A shown in  FIGS. 15 a , 15 b , and 15 c   , the clamping member  80  may be guided over the elongate outer member  75  and into the circumferential groove by an insertion member  130 . For example, insertion member  130  may be connected to clamping member  80  with a releasable coupling member  133 . The insertion member  130  may be configured to push the clamping member  80  into circumferential groove  45  and over elongate outer member  75 . In embodiments, the insertion member  130  may be configured to pull the clamping member  80 . The coupling member  133  may include an interference fit between the clamping member  80  and the insertion member  130 , or for example, the coupling member  133  may include a luer lock, or any suitable releasable latch. The coupling member  133  may be configured to selectively release the clamping member  80  from the insertion member  130  and/or may be configured to selectively re-attach the clamping member  80  to the insertion member  130 . 
     The clamping member  80 /elongate outer member  75  (e.g., when it comprises an elastic and/or compressible material, e.g., as described above) may serve to dampen movement of the heart (e.g., caused by the beating heart, e.g., pulse) by acting as a dampening and/or cushioning member between the heart (e.g., a heart chamber) and the prosthesis  1  (e.g., tubular body  30 ) to further improve the fixation of the prosthesis  1  relative in the heart by reducing forces caused by the beating heart acting on the prosthesis  1  by dampening these forces. Accordingly, the clamping member  80 /elongate outer member  75  may absorb movements (e.g., of the ventricular wall (e.g., of the papillary muscle of the ventricular chamber  20 ) to reduce or avoid pulsation of the prosthesis  1 . The clamping member  80  may serve to maintain a distance of the prosthesis  1  from tissue of the heart (e.g., from a wall of the ventricular chamber  20  and/or the atrial chamber  15 ) and thereby improve placement and/or fixation of the prosthesis  1 . Accordingly, the elongate outer member  75  and/or the clamping member  80  may serve as a damping member and/or a spacer member. The clamping member  80  and/or the elongate outer member  75  and hence, the groove  45 , may be arranged on a side of the ventricular chamber when seen from the annulus of the natural valve having a distance from the annulus. 
     The shape of a cross section of tubular body  30  across its longitudinal axis (e.g., axis  35 ) may vary. Catheter member  90  may comprise or provide a piercing component that can be positioned through the connection channel wall structure  25  (e.g., from an outside of connection channel wall structure  25 ) and through the tubular body  30  in substantially diametrically opposite positions relatively to an axial (with respect to axis  35 ) cross section. The piercing component may be hollow and enable placement of an anchor on connection channel wall structure  25  at the distal position of a diameter of the connection channel wall structure  25  relatively to catheter member  90 . Said anchor may be attached to a longitudinal end of a longitudinal component (e.g., a tether), which in turn may be provided with a second anchor on its other longitudinal end. The second anchor may be placed by the piercing component upon retrieval of the piercing component from the connection channel wall structure  25  at the proximal end (relative to catheter member  90 ) of said diameter on connection channel wall structure  25 . The length of said longitudinal component can be designed to be under tension from forces acting on the longitudinal component induced by the first and second anchors, so as to create a deformation of tubular body  30  in a substantially elliptical shape, e.g., the longitudinal component may be shorter than a diameter of the tubular body  30  when no external forces act upon tubular body  30 . The longitudinal component may be placed across an inner lumen of tubular body  30  in a position where it does not interfere with the function of valve  40 , e.g., be geometrically spaced away from the valve  40 . It may be small enough to avoid significant interference with blood flow through tubular body  30 , e.g., may have a radius or a diameter ranging from 100 μm to 1000 μm. 
     In embodiments, the transcatheter valve prosthesis  1  may include fabric  120  disposed at least partially around the tubular body. For example, as shown in  FIGS. 16 a  and 16 b   , the fabric  120  may be disposed around an outer circumference of tubular body  30  and over second end  69  of projection  55  such that the fabric forms a pouch  22  between the tubular body  30  and projection  55 . The pouch  122  serves to prevent tissue and/or the clamping member  80  from sliding down too far between the tubular body and projection  55 . For example, the pouch  122  may correspond to chamber  66  disposed between tubular body  30  and projections  50  and/or  55 . In embodiments, the tubular body  30  may include the second plurality of projections  55  and the fabric  120  may be disposed over the second end  69  of the second plurality of projections  55  ( FIG. 16 b   ). In embodiments, the fabric  120  may be disposed over both the first and second plurality of projections  50 ,  55 . 
     The fabric  120  may comprise liner  33   b , as described above, and may include a first end  124  attached to the inflow end of the tubular body  30  and a second end  126  as shown in  FIGS. 16 a  and 16 b   . The fabric  120  between the first end  124  and the second end  126  may include sufficient slack to form pouch  122 . In embodiments, the second end  126  may be attached to the tubular body  30  in a vicinity of the outflow end of the tubular body  30 . Alternatively, the second end  126  of the fabric  120  may be attached to the second end  69  of a projection  50 ,  55 , as shown in  FIGS. 17 a , 17 b , 17 c , 17 d , and 17 e   . The second end  126  may be attached at a very distal end of second end  69  ( FIG. 17 a   ), or the second end  126  may be attached at a connection point  167  that is adjacent to the very distal end of second end  69  ( FIGS. 17 c  and 17 d   ). The fabric  120  may be attached to the tubular body  30  or projection  50 ,  55  by, for example, sutures, adhesives, clamps, or any attachment means known in the art. In embodiments, the second end  126  may be unattached to the tubular body  30  and include a free end, as shown in  FIG. 18 . The free end of second end  126  may extend substantially the entire length of stent  30  ( FIGS. 16 a , 16 b   , and  18 ), or the free end of second end  126  may be shorter than the length of the stent, for example as shown in  FIGS. 17 b -17 e   . In other embodiments, the length of second end  126  may be shorter or longer than the embodiments shown in  FIG. 16 a    through  FIG. 18 . 
     The fabric  120  may include one or more segments of material. In embodiments, the fabric  120  includes one segment of material that completely circumscribes the tubular body  30 . In embodiments, the fabric  120  may include multiple segments, for example, two, four, or six. The segments may be spaced apart, providing gaps between adjacent segments. Alternatively or in addition, some or all adjacent segments may overlap. The fabric  120  maybe continuous with, for example, liner  33   b  ( FIG. 6 a   ). The fabric  120  may be made from polyester fabric (e.g., DACRON® or other PTFE graft material). 
     Elongate outer member  75  and clamping member  80  may be moved into the pouch  122  and trap tissue within the pouch  122 , for example as shown in  FIG. 17 e   . Movement of the elongate outer member and/or clamping member  80  into the pouch  122  may provide tension on fabric  120 , causing the fabric  120  to be taut. Thereby, the tissue may be trapped between the tubular body  30  and the projection  55 . The fabric  120  may then located between the tubular body  30  and the trapped portions of tissue (e.g., native valve leaflets and/or chords), and between the trapped portions of tissue and the projection  55 . 
     In embodiments, the fabric  120  may be attached to tubular body  30  with sufficient slack to form a pouch, but the pouch  122  may not be formed until elongate outer member  75  and/or clamping member  80  is/are moved into contact with the fabric  120  between the tubular body  30  and the projection  55 . Then the elongate outer member  75  and/or clamping member  80  forms the pouch  122  such that the size of the pouch  122  corresponds to the size of the elongate outer member  75  and/or clamping member  80 . 
     As shown in  FIGS. 26 and 27 , the barbs  230  may be configured to at least partially pierce through fabric  120  when the barbs  230  pierce the portions of native valve leaflets and/or chords. The piercing of the fabric  120  by barbs  230  may help to secure the prosthesis to the native valve leaflets and/or chords. 
     All embodiments of the transcatheter valve prosthesis  1  may comprise positioning and/or orientation devices to facilitate relative and/or absolute positioning of the tubular body  30  and/or the elongate outer member  75  and/or the clamping member  80 . These devices may include passive markers that are fixedly attached to the tubular body  30  and/or the elongate outer member  75  and/or the clamping member  80 . The passive markers may be made from materials different from the materials of the tubular body  30  and/or the elongate outer member  75  and/or the clamping member  80  in order to improve contrast during medical imaging, e.g., using magnetic resonance or X-ray based imaging techniques. The passive markers may, e.g., be made of highly radio-opaque materials thereby allowing one to precisely acquire the relative and/or absolute position of the components of the transcatheter valve prosthesis  1  with respect to the patient&#39;s body. The passive markers may each have an asymmetrical shape so as to allow identification of the absolute and/or relative position and orientation and thereby the position and orientation of the tubular body  30  and/or the elongate outer member  75  and/or the clamping member  80 . The passive markers may have an identical shape and may be arranged in a certain configuration relative to each other to allow recognition of the orientation. The circumferential groove  45  of the tubular body  30  and/or the tubular body  30  and/or the elongate outer member  75  and/or the clamping member  80  may have passive markers fixedly attached to facilitate positioning them relative to each other using imaging techniques, e.g., passive markers made of highly radio-opaque materials when imaging techniques based on electro-magnetic radiation (e.g., X-ray imaging) are used. In addition and/or as an alternative, the circumferential groove  45  and/or other parts/components of the tubular body  30  and/or the elongate outer member  75  and/or the clamping member  80  may be made from radio-opaque materials. 
     A method for using a transcatheter prosthesis  1  as described above may comprise:
         Placing the transcatheter valve prosthesis  1  within an atrio-ventricular valve, e.g., in a mitral or a tricuspid valve of a human or animal heart, via an insertion catheter. The transcatheter valve prosthesis  1  may, e.g., be placed in a connection channel wall structure  25  between a ventricular chamber  20  and an atrial chamber  15  as shown in  FIG. 1 .       

     To place transcatheter valve prosthesis  1  within the heart valve, the following approaches may be applied: 1) an arterial retrograde approach entering the heart cavity over the aorta, 2) through a venous access and through a puncture through the inter atrial septum (trans-septal approach), 3) over a puncture through the apex of the heart (trans-apical approach), 4) over a puncture through the atrial wall from outside the heart, 5) arterial access (e.g., from the femoral artery through a puncture in the groin), or 6) any other approach known to a skilled person. The approach to the valve is facilitated as the tubular body  30  is radially compressible and extendable and may, e.g., be folded and stuffed in a catheter during approach and may be unfolded/extended when within the circumferential connection channel wall structure  25 . The transcatheter valve prosthesis  1  may include the clamping member  80  or the clamping member  80  may be inserted separately via one of the mentioned approaches (e.g., using a catheter) so as to be placed in the circumferential groove  45  of the tubular body  30  when the tubular body  30  is located in the connection channel wall structure  25 . The clamping member  80  may be compressible and expandable.
         Fixing the transcatheter valve prosthesis  1  in the heart relative to the valve.       

     For functional replacement of a heart valve, the transcatheter valve prosthesis  1  is fixed relative to the connection channel wall structure  25  and sealed against blood flow on the exterior of the transcatheter valve prosthesis  1  in the connection channel wall structure  25 . To achieve this, tissue of the connection channel wall structure  25  adjacent to the circumferential groove  45  may be forced or placed inside the circumferential groove  45  to engage radially below the first  50  and second  55  pluralities of projections whereby the tissue is prevented from slipping out of the groove  45  by the first  50  and/or second  55  plurality of projections, wherein the free ends  60 ,  65  of the first  50  and/or second plurality  55  of projections may penetrate the tissue. The tissue of the connection channel wall structure  25  may be (completely) perforated, or for example partially perforated, by the projections  50 ,  55  and may thereby be prevented from slipping out of the circumferential groove  45 . The clamping member  80  or two or more clamping members  80  may be provided in the circumferential groove  45  to actively press tissue of the connection channel wall structure  25  against the free ends  60 ,  65  so as to interlock the tissue with the free ends  60 ,  65 . This results in the transcatheter valve prosthesis  1  being held in place more firmly and sealed against blood flow between the exterior of the tubular body  30  and the connection channel wall structure  25 . 
     To place tissue in the circumferential groove  45  of the tubular body  30 , a method for using a transcatheter valve prosthesis  1  may comprise using an elongate outer member  75  to radially and inwardly force tissue of die connection channel wall structure  25  into the circumferential groove  45  (which may or may not comprise a clamping member  80 ). With reference to  FIG. 3 , the elongate outer member  75  may be disposed at an exterior of the connection channel wall structure  25  at a level of the circumferential groove  45 . Then, with further reference to  FIG. 6 b   , a distance R 5  between the elongate outer member  75  and the axis  35  of the tubular body is reduced (that means that also a distance between the bottom  46  of the circumferential groove  45  of the tubular body  30  and the elongate outer member  75  is reduced) so as to force tissue of the connection channel wall structure  25  into the circumferential groove  45  to fix the tissue in the circumferential groove  45 . In embodiments, the elongate outer member  75  slides along the slope of a partially deployed tubular body  30  to force tissue of the connection wall structure  25  into the circumferential groove  45 . The elongate outer member  75  may be handled via a catheter member  90  and an approach as described in relation to the transcatheter valve prosthesis  1  or any other approach may be used in order to bring the elongate outer member  75  into the vicinity of the connection channel wall structure  25 . 
     After the elongate outer member  75  is disposed within the circumferential groove  45  so as to fix tissue with the groove  45  and the tubular body  30  is fully deployed, the clamping member  80  may be guided along the elongate outer member  75  such that the clamping member  80  is disposed over and coaxial with the loop of the elongate outer member  75  within groove  45 . For example, the clamping member  80  may be advanced between at least two stent struts  107  and/or projections on the tubular body  30  in order to be slid over the elongate outer member  75 . The clamping member  80  may then trap the tissue (e.g., native valve leaflets and/or chords) within the circumferential groove  45 . In embodiments, an insertion member  130  may push the clamping member  80  between the stent struts  107  and over the elongate outer member  75 . A coupling member  133  may release the insertion member  130  from the clamping member  80 . 
     In embodiments, the clamping member  80  may be moved into the circumferential groove  45  when the tubular body  30  is partially deployed. For example, when the outflow end but not the inflow end of the tubular body  30  is deployed from a delivery catheter such that the circumferential opening of groove  45  is relatively larger (as compared to when the tubular body  30  is fully deployed), the clamping member  80  may be moved into the circumferential groove  45 . The clamping member  80  may be slid along the tubular body  30  (for example, in a direction from the outflow end toward the inflow end of the tubular body  30 ) into the circumferential groove  45  to trap tissue within the groove. 
     When the tissue of the connection channel wall structure  25  is held in the circumferential groove  45  by the projections  50 ,  55 , the elongated member  75  (and the catheter member  90 ) may be removed from the heart or, as shown illustratively in  FIG. 7 , the connecting means  91  of the catheter member  90  may be used in order to permanently connect two (free) ends of the elongate outer member  75  together and optionally cut the ends so that elongate outer member  75  remains permanently on the exterior of a connection channel wall structure  25  on a level of the circumferential groove  45  of the tubular body  30  so as to additionally hold tissue of the connection channel wall structure  25  in the circumferential groove  45 . 
     In embodiments, elongate outer member  75  may radially and inwardly force tissue of connection channel wall structure  25  into contact with fabric  120  and between the tubular body  30  and the projection  55 . This movement of elongate outer member  75  may guide native valve leaflets and/or chords into circumferential groove  45 , wherein the circumferential groove  45  is formed between the tubular body  30  and the projection  55 . Movement of elongate outer member  75  into circumferential groove  45  may guide the native valve leaflets and/or chords into contact with fabric  120  to form pouch  122 . The fabric  120  may thus change from slack to taut to form pouch  122 . The clamping member  80  may further be advanced into pouch  122  to trap the tissue within pouch  122 . 
     In embodiments, the insertion member  130  may push the clamping member  80  into the circumferential groove  45  and over the elongate outer member  75 . For example, the insertion member  130  may push the clamping member  80  between at least two stent struts  107  and into the circumferential groove  45 . The coupling member  133  may selectively release the clamping member  80  from the insertion tube  130  after the clamping member  80  is within the circumferential groove  45  ( FIG. 15 c   ). In embodiments, releasing and removing the elongate outer member  75  from the tubular body  30  releases the clamping member  80  from the insertion member  130 . The clamping member  80  and the insertion member  130  may be re-attached with the coupling member  130  after the step of releasing the clamping member  80  from the insertion member  130 . The clamping member  80  may then be repositioned within the patient. Additionally, the tubular body  30  and elongate outer member  75  may also be repositioned within the patient. After re-positioning the clamping member  80  within the patient, the coupling member  133  may re-release the clamping member  80  from the insertion member  130 . 
     A method for using the transcatheter atrio-ventricular prosthesis  1  may result in the transcatheter valve prosthesis  1  being fixed to the connection channel wall structure  25  and being firmly held in place via the tissue that is held in the circumferential groove  45  by the free ends  60 ,  65 , optionally supported by the clamping member  80  and/or the permanently disposed elongate outer member  75 . 
     A method for using the transcatheter atrio-ventricular prosthesis  1  may also result in fixation of tubular body  30  to the connection channel wall structure  25  with minimal occlusion of the patient&#39;s valve. For example, the elongate outer member  75  may be advanced to the patient&#39;s native valve within a first delivery catheter, for example through the patient&#39;s femoral artery. The elongate outer member  75  may form a loop around the patient&#39;s native valve without substantially occluding the valve. The tubular body  30  may be advanced to the patient&#39;s native valve within a second delivery catheter, for example through the patient&#39;s atrial wall. The tubular body  30  may be partially deployed from the second delivery catheter such that the outflow end but not the inflow end of the tubular body  30  is deployed from the second delivery catheter. Only for the brief time that the tubular body  30  is partially deployed, the patient&#39;s native valve may be substantially occluded. The elongate outer member  75  may then move into the circumferential groove  45  when the tubular body is partially deployed, and thereby move the patient&#39;s native valve leaflets and/or chords into the groove  45 . Once the tubular body  30  is fully deployed, the patient&#39;s native valve may no longer be substantially occluded. Therefore, the method may include only substantially occluding the native valve only when the tubular body  30  is partially deployed and not yet anchored in position by elongate outer member  75 . Additionally, clamping member  80  may be advanced over the elongate outer member  75  without substantially occluding the native valve. For example, as discussed above, the clamping member may be advanced over the elongate member  75  and around the fully deployed or partially deployed tubular body  30 . 
     Features of the transcather atrio-ventricular valve prosthesis  1  and method steps involving the prosthesis that have been described herein (description and/or figures and/or claims) referring to a transcather atrio-ventricular valve prosthesis  1  comprising first  50  and second  55  pluralities of projections also apply to a transcatheter atrio-ventricular valve prosthesis  1  comprising one plurality of projections ( 50 ,  55 ) and vice versa. In particular, features described in the application (description, claims, figures) to further define the projections of the first and second plurality of projections are also applicable to only the first plurality of projections if, for example, the valve prosthesis only comprises the first plurality of projections. All features herein are disclosed to be interchangeable between all embodiments of the transcather atrio-ventricular valve prosthesis  1 .