A
valve prosthesis device is disclosed suitable for implantation in body ducts. The device comprises a support
stent, comprised of a deployable construction adapted to be initially crimped in a narrow configuration suitable for catheterization through the body duct to a target location and adapted to be deployed by exerting substantially radial forces from within by means of a deployment device to a deployed state in the target location, and a valve
assembly comprising a flexible conduit having an inlet end and an outlet, made of pliant material attached to the support beams providing collapsible slack portions of the conduit at the outlet. The support
stent is provided with a plurality of longitudinally rigid support beams of
fixed length. When flow is allowed to pass through the
valve prosthesis device from the inlet to the outlet, the valve
assembly is kept in an open position, whereas a reverse flow is prevented as the collapsible slack portions of the valve
assembly collapse inwardly providing blockage to the reverse flow. The device is configured so that
retrograde flow will be altered from laminar flow and directed towards the leaflets to effect closing.