A prosthetic valve (100) comprising:a plurality of leaflets (130), each leaflet defines a leaflet first side region and a leaflet second side region opposite from the leaflet first side region, each leaflet defining a leaflet base (134) and a leaflet free edge (142) opposite from the leaflet base, each leaflet first side region is coupled with the leaflet second side region of an adjacent leaflet at a commissure (136), the leaflet base of each of the plurality of leaflets together define an orifice, at least a first portion of the leaflet first side region having a first thickness and the second side region having a second thickness, the first thickness is greater than the second thickness. These leaflets move asymmetrically in that a leaflet second side region of the leaflet initially moves toward the open position before a leaflet first side region and the leaflet first side region initially moves toward the closed position before the leaflet second side region. In the fully open position, the leaflet first side region opens less than the leaflet second side region. Asymmetric opening and final open position creates spiral flow. Controlled asymmetric movement of the leaflet reduces closing volume.
