Early years in artificial valve development.

Various types of prosthetic heart valves developed and tested in the laboratory beginning in 1958 are described. Seven of such valves were implanted clinically in patients with congestive heart failure previously operated on by both the closed and open techniques in 1958 and 1959. The longest survivor was 6 weeks. Evidence is presented demonstrating that putting a film of polyurethane on the Teflon leaflet valve and fixation rings of disc valves reduces thrombosis, thromboembolism, and tissue overgrowth interfering with disc or ball valve function.