Superiority of mitral valve repair in surgery for degenerative mitral regurgitation

Objectives We aimed to assess the influence of type of operation on outcome in degenerative mitral regurgitation. Methods We compared outcomes in 278 consecutive patients who underwent mitral valve repair (167 patients), replacement with subvalvular preservation (22 patients) and without subvalvular preservation (89 patients) for degenerative mitral regurgitation. Results There was a trend towards lower mortality with repair and replacement with subvalvular preservation compared to replacement without subvalvular preservation. Thirty-day mortality was 1·2% vs 0·0% vs 4·7% (ns) respectively. Six-year survival was, respectively, 67·8±7·4% (P=0·088) vs 80·8±11·0% (P=0·25 vs 63·3±5·9% for all-cause death, 78·5±6·8% (P=0·063) vs 95·5±4·4% (P=0·092) vs 67·6±5·9% for all complication-related death and 80·5±6·9% (P=0·076) vs 100·0±0·0% (P=0·045) vs 72· ± 5·8% for complication-related death due to myocardial failure. Multivariate analysis confirmed independent beneficial effects from repair compared to replacement without subvalvular preservation on complication-related death (hazard ratio 0·42, P=0·010) and death from myocardial failure (hazard ratio 0·40 P=0·014), and from repair compared to mechanical replacement on thromboembolism (hazard ratio 0·45, P=0·029) and anticoagulation-related haemorrhage (hazard ratio 0·19, P=0·026). Conclusions Mitral valve repair is superior to replacement. The greatest survival advantage is in reduced mortality from myocardial failure. Repair should be the operation of choice for degenerative mitral regurgitation.