Prosthetic heart valves having fiber reinforced leaflets

A prosthetic heart valve comprising:

• a tubular body, and
• three leaflets coupled to the tubular body, each leaflet comprising a fibrous composite material composed of a plurality of electrospun fibers at least partially embedded in a polymer matrix, wherein the polymer matrix comprises a polyisobutylene urethane block copolymer,
• wherein the plurality of electrospun fibers comprise a first polyisobutylene urethane block copolymer having a first predetermined weight average percentage of hard segment portions and soft segment portions;
• the polyisobutylene urethane block copolymer of the polymer matrix comprises a second polyisobutylene urethane block copolymer having a second predetermined weight average percentage of hard segment portions and soft segment portions;
• and
• the first predetermined weight average percentage of hard segment portions is greater than the second predetermined weight average percentage of hard segment portions.