Heart valve provided herein may include small intestinal submucosa (P-SIS) tissue leaflet of a pig. P-SIS tissues may include multiple stack layer, is tightened up and makes its crosslinking to be formed in 50 microns and 0.Between 33 millimeters with a thickness of a kind of material. In some cases, a heart valve can include fixed multiple leaflets and keep within expandable tubular member together.