Prosthetic valve devices, as well as systems and methods for the delivery thereof, are disclosed. A device includes one or more leaflets disposed within a frameless conduit, wherein the conduit is adapted for attachment to walls of a vascular vessel, and the leaflets are adapted for attachment to walls of the conduit. The leaflets are configured to selectively restrict blood flow through the conduit, and the conduit can include wall-engaging adaptations, for example, barbs or an adhesive. The conduit and the leaflets are formed with a flexible material, which may comprise a remodelable material and/or a synthetic polymer.
