This document discusses heart valve replacement and repair surgery. It begins by introducing the four heart valves and the types of valve disease that require surgery. There are two main types of valve replacement - mechanical and biological prosthetic valves. The procedures for replacing the aortic, mitral, tricuspid and pulmonary valves are described. Minimally invasive surgical techniques and trans catheter valve replacements are also discussed. The document concludes by considering complications, contraindications and factors in deciding between valve repair or replacement.