They are made of a combination of metal alloys, pyrolite carbon and dacron.
Types of Mechanical Valves
Caged-ball Valve (Star-Edwards)
A metal cage with several struts mounted in a circular ring, hollow metal or plastic ball inside cage. Durability is high, but possibility of blood clots forming on or around the valve with the risk of embolism is high.
Tilting Disc Valve (Bjork-Shiley Medtronic Hall)
Mobile lens shaped disc attached to a circular sewing ring by two offset transverse struts. This has high durability and efficiency.
Two pivoting semi-circular discs that open centrally, mounted
Directly onto a sewing ring.