- We review the data of 141 patients who underwent mitral valve replacement between 1964 and 1986. In the majority of patients, a tilting disk or a Cage ball prosthesis was implanted. Overall operative mortality was 14.8%, and 120 patients who were followed for a mean period of 4.5 +/- 2 years (540 patient years) showed a late mortality (greater than 30 days postoperatively) of 20.8%. The actuarial survival was 84% at 5 years and 44% at 20 years. Most of the late deaths were cardiac related, with sudden death as the leading cause. The incidence of prosthetic valve-related complications--thromboembolism, bacterial endocarditis and warfarin-related hemorrhage--were higher than in other series; however, long-term survival was comparable. Delay in advising mitral valve surgery is the probable cause of some of the results observed in this series.