The present invention relates to a prosthesis and a method for extending the valve leaflets (2a, 2b, 2c) of a heart valve (2) using the prosthesis (1). The prosthesis (1) comprises at least two strip elements (3-5), each of which has two opposed ends (3a, 3b, 4a, 4b, 5a, 5b) and two opposed edges (3c, 3d, 4c, 4d, 5c, 5d). The prosthesis is characterized in that the at least two strip elements (3-5) are connected at their ends (3a, 3b, 4a, 4b, 5a, 5b) to form cusps and in that it comprises additional plate elements (9-11) connected to said strip elements (3-5) at said cusp points.
