The present invention relates to a stent (10) for theposi-tioning and anchoring of a valvular prosthesis (100) in an implantationsite in the heart of a patient. Specifically, the present invention relates toan expandable stent for an endoprosthesis used in the treatment of anar-rowing of a cardiac valve and/or a cardiac valve insufficiency. So as toen-sure that no longitudinal displacement of a valvular prosthesis (100)fas-tened to a stent (10) will occur relative the stent (10) in the implantedstateof the stent (10), even given the peristaltic motion of the heart, the stent(10) according to the invention comprises at least one fastening portion(11 11a) via which the valvular prosthesis (100) is connectable to the stent(10). The stent (10) further comprises positioning arches (15a, 15b, 15c)and retaining arches (16a, 16b, 16c), whereby at least one positioning arch(15a, 15b, 15c) is connected to at least one retaining arch (16a, 16b, 16c)via a first connecting web (17). The stent (10) moreover comprises at leastone auxiliary retaining arch (18a, 18b, 18c) which connects the respectivearms (16a', 16a", 16b', 16b", 16c', 16c") of the at least one retaining arch(16a, 16b, 16c) connected to the at least one positioning arch (15a, 15b,15c).
