When to replace heart valves.
D000293:Adolescent; D000368:Aged; D004992:Ethics, Medical; D006349:Heart Valve Diseases / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000637:transplantation*; D006801:Humans; D011379:Prognosis; D014184:Transplantation, Homologous