delivering the endoprosthesis to the native heart valve in a compressed state, the endoprosthesis comprising an expandable stent comprising a plurality of retaining arches, a plurality of positioning arches, a plurality of connecting struts coupling the plurality of retaining arches to the plurality of positioning arches, and a plurality of auxiliary arches uniformly distributed around a lower end of the expandable stent and configured to press against a vascular wall, each auxiliary arch coupled at a primary end of each auxiliary arch to a first retaining arch of the plurality of retaining arches and coupled at a secondary end of each auxiliary arch to a second retaining arch of the plurality of retaining arches, the plurality of auxiliary arches and the plurality of retaining arches configured to form a seal with a vascular wall;

causing the plurality of positioning arches to at least partially expand;

positioning, after causing the plurality of positioning arches to at least partially expand, the plurality of positioning arches into pockets of the native heart valve; and

causing, after positioning the positioning arches into pockets of the native heart valve, the plurality of retaining arches to at least partially expand, thereby clipping at least one native leaflet of the native heart valve between at least one of the plurality of retaining arches and at least one of the plurality of positioning arches,

wherein the plurality of connecting struts offset the plurality of positioning arches form the plurality of the retaining arches.