An valve prosthesis, such as an artificial venous valve, having a support
frame and leaf structure comprising one or more leaflets in which the
outer edge of each leaflet engages the inner circumference of the bodily
passageway along a serpentine path urged against the passageway by an
expandable frame, while the inner edges move in response to fluid to
restrict retrograde flow. Optionally, one or more elements can extend
from the support frame/leaf structure to provide centering support and/or
protection from the leaflet adhering to the vessel wall. In one
embodiment, the centering support structure comprises a second or third
expandable frames attached to and extending from the proximal and/or
distal ends of main valve structure and support frame. In another
embodiment, one or more support elements extend outward from the valve
support frame to engage the vessel wall to provide greater longitudinal
stability.