Mechanical heart valves: 50 years of evolution.

The past 50 years have witnessed remarkable progress in the development of safe, hemodynamically favorable mechanical heart valves. Starr-Edwards aortic and mitral ball valves introduced in the mid-1960s, continue to be used successfully worldwide. More than 100,000 Omniscience and Omnicarbon tilting-disc valves have been implanted since 1978 with essentially no mechanical failure; similar results have been obtained with more than 300,000 Hall-Kaster and Medtronic-Hall tilting-disc valves over the past 25 years. Pyrolytic carbon, originally used to encapsulate nuclear fuel rods, has been adapted for the fabrication of discs, leaflets and the housings for more than 2 million mechanical valves. The St. Jude bileaflet valves, totally fabricated from pyrolytic carbon, have remained virtually unchanged in design since their introduction in 1977. More than 1.3 million of these valves have been implanted worldwide with virtually no reported failures of the carbon leaflets or housings. Similarly, pyrolytic carbon bileaflet Carbomedics valves have been implanted in more than 500,000 patients since 1986. Now, 50 years after Dr Gibbon's seminal achievement, patients with debilitating valve disease can have elective valve replacement (mechanical or tissue) with an operative mortality approaching 1% to 2% and a low lifetime complication rate.