Results of Randomized Mitral Valve Replacement with Mechanical Prostheses after 15 Years

Abstract

Between 1974 and 1976 150 consecutive patients (pts) were operated on for isolated mitral valve replacement (MVR). Björk-Shiley (BS), Lillehei-Kaste (LK), and Starr-Edwards (SE) (type 6210) prostheses were implanted at random. All survivors were prospectively followed by regular clinical examinations every 6 to 12 months for 15 years. The mean follow-up time was 14.8 years. A constant subjective improvement after 15 years was reported in 62% of pts with BS, 30% with LK, and 49% with SE. The cumulative 14-year survival rate was 0.62 +/- 0.13 (BS), 0.56 +/- 0.16 (SE), and 0.54 +/- 0.15 (LK), respectively. Late mortality was due to thromboembolic events (n = 3), bleeding complications (n = 3), congestive heart failure (n = 7), documented arrhythmias or sudden death (n = 6). Thrombotic valve thrombosis (1 BS, 1 LK, 2 SE) required reoperations. Linearized cumulative rates after 14 years for thromboembolic complications were 14.2 +/- 3.1 (BS), 15.8 +/- 3.7 (SE), 24.3 +/- 4.2 (LK). The cumulative risk of severe bleeding complications was not different: BS: 35.8, LK: 35.2, SE: 34.3. During the first years of observation no significant differences between these mechanical prostheses could be observed, however, after 14 years of long-term follow-up the cumulative event-free rates were more favorable for the BS prosthesis.