A heart valve assembly has a leaflet support structure and a leaflet assembly. The leaflet support structure has a wire frame that supports the leaflet assembly. The leaflet assembly has first and second separate leaflets, each of which is comprised of a skirt section and a sinus leaflet section. Each skirt section has a flange portion and a body portion that has a smaller diameter than the flange portion, with the body portion having opposing side edges, and a curved opening defined by a first stitching edge at about the central portion of the body portion. Each sinus leaflet section has an outflow edge, and a curved second stitching edge, with the sinus leaflet section stitched to the skirt section along the first and second stitching edges. The opposing side edges of the body portion of the first leaflet are stitched to the corresponding side edges of the body portion of the second leaflet.