Annular prosthesis for mitral valve

DETAILED DESCRIPTION What is claimed is: 1.
An annular prosthesis for a mitral valve comprising a posterior half-ring and an anterior half-ring coupled to each other on a first transverse plane at two coupling points, the first transverse plane defining a maximum width section of the prosthesis, wherein the ratio between (a) the distance between said anterior half-ring and said posterior half-ring, as measured along a second plane that is perpendicular to the first plane and equidistant to said coupling points and (b) the maximum width of said prosthesis is lower than 3/4.
2.
The annular prosthesis of claim 1, wherein said ratio is lower than or equal to 2.
5/4.
3.
The annular prosthesis of claim 1, wherein said posterior half-ring has a gull wing shape.
4.
The annular prosthesis of claim 3, wherein said posterior half-ring is symmetrical with respect to the second plane.
5.
The annular prosthesis of claim 1, wherein said posterior half-ring is symmetrical with respect to the second plane.
6.
The annular prosthesis of claim 1, wherein is said posterior half-ring is asymmetrical with respect to the second plane.
7.
The annular prosthesis of claim 6, wherein one lateral portion of said posterior half-ring has a radius of curvature that is smaller than the other lateral portion of said posterior half-ring.
8.
An annuloplasty ring for a mitral valve comprising a posterior half-ring and an anterior half-ring coupled to each other on a first transverse plane at two coupling points, the first transverse plane defining a maximum width section of the ring, wherein the ratio between (a) the distance between said anterior half-ring and said posterior half-ring, as measured along a second plane that is perpendicular to the first plane and equidistant to said coupling points, and (b) the maximum width of said ring is lower than 3/4.
9.
The annuloplasty ring of claim 8, wherein said ratio is lower than or equal to 2.
5/4.
10.
The annuloplasty ring of claim 8, wherein said posterior half-ring has a gull wing shape