USEFUL knowledge results from information collected in the past and synthesized, condensed, and organized to provide the best possible clue to future performance. Our purpose here is to arrive at that point by a review of the experience with heartvalve replacement during the last 30 years. Examination of data from current prostheses must be viewed from the perspective of experience, not expectations.
ORIGINS OF VALVE REPLACEMENT: THE 1950s
The earliest valvular substitute was Hufnagel's ball valve inserted into the descending aorta in 1952. With the introduction of cardiopulmonary bypass in 1953 came the possibility of complete replacement of cardiac valves in their anatomic position, and many laboratories and investigators devised replacement prostheses. Among the devices tried were artificial trileaflet valves made of pericardium, Teflon, Dacron, polyurethane, and Silastic; monocusp flap valves made of steel, polyester film (Mylar), or Silastic; and other configurations, including butterfly, sleeve, bicuspid, and quadricuspid made from