Valve replacement.
D005500:Follow-Up Studies; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000601:surgery; D006350:Heart Valve Prosthesis / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology; D011300:Preoperative Care; D012306:Risk