Abstract: A method of manufacturing a heart valve prosthesis includes cutting a flat sheet of a valve material into a single-piece valve pattern having two or more valve leaflet regions and a valve skirt region. The method also includes arranging the two or more valve leaflet regions of the single-piece valve pattern into a mold for forming a leaflet belly for each of the two or more valve leaflet regions. Further, the method includes fixing, while arranged in the mold, a shape of the leaflet belly of each of two or more valve leaflet regions of the single piece-valve pattern. The method additionally includes creating a side seam by attaching two longitudinal edges of the single-piece valve pattern, to thereby form a tubular valve subassembly with two or more valve leaflets. The method includes attaching the tubular valve subassembly within a tubular frame to form a heart valve prosthesis.