An expandable stent (10) comprising a plurality of positioning arches (15a, 15b, 15c), in particular three positioning arcs (15a, 15b, 15c), a plurality of retention arcs (16a, 16b, 16c), in particular three retention arches (16a, 16b, 16c), configured to support a heart valve prosthesis (100), and at least one holding part (11, 11a) by means of which the heart valve prosthesis (100 ) can be connected to the stent (10), in which the positioning arches (15a, 15b, 15c) are connected to the retention arches (16a, 16b, 16c) by means of first connecting pins (17), and in which each of the positioning arches (15a, 15b, 15c) is configured to be placed between the vascular wall and a leaf of a natural heart valve and configured to cooperate with a corresponding retention arch (16a, 16b, 16c ) with the result of the clamping of the natural leaf between the two arches； characterized in that the stent (10) further comprises at least one auxiliary arc (18a, 18b, 18c) that projects radially towards the stent (10) in the expanded state of the stent (10) such that the at least one auxiliary arc (18a, 18b, 18c) presses against the vascular wall in which the stent (10) is deployed with a force of tension of radial action in the implanted state of said stent (10) so that said stent (10) is anchored , wherein the at least one auxiliary arc (18a, 18b, 18c) connects a first retention arc of the plurality of retention arcs (16a, 16b, 16c) with a second retention arc of the plurality of retention arcs (16a, 16b, 16c) neighbor to the first retention arcUn estent expandible (10) que comprende una pluralidad de arcos de colocación (15a, 15b, 15c), en particular tres arcos de colocación (15a, 15b, 15c), una pluralidad de arcos de retención (16a, 16b, 16c), en particular tres arcos de retención (16a, 16b, 16c), configurados para soportar una prótesis de válvula cardíaca (100), y al menos una parte de sujeción (11, 11a) por medio de la cual la prótesis de válvula cardíaca (100) puede conectarse
