A system for implanting a heart valve includes a radially self-expandable tubular body having an inflow end and an outflow end and a preformed groove disposed at an outer surface of the tubular body between the inflow end and the outflow end. The preformed groove extends at least partially around the tubular body, and has a circumferential opening facing radially outward of the tubular body. A valve is disposed within and attached to the tubular body, and a trapping member is configured to be moved into the preformed groove and form at least a partial loop around the preformed groove. An insertion member is configured to push the trapping member into the preformed groove. Additionally, a coupling member can provide a releasable attachment between the trapping member and the insertion member.