Mitral valve repair: results and the decision-making process in reconstruction. Report of 275 cases

From January 1975 to June 1988, 275 patients underwent mitral valve repair for mitral regurgitation, pure (148 patients) or associated with mitral stenosis (127 patients). Patients with pure mitral stenosis were excluded from this study. The cause of mitral regurgitation was rheumatic in 180 patients (aged 28.6 +/- 1.2 years, mean +/- standard error of the mean) and degenerative in 84 patients (aged 54.7 +/- 1.5 years). Fifty-nine percent of the patients were in New York Heart Association classes III and IV before the operation. Intraoperative assessment of the mitral valve led us to identify four major mechanisms of mitral regurgitation: (1) restriction of leaflet motion by fibrosis (group I, 63 patients); (2) enhancement of leaflet motion by leaflet and chordal extension and prolapse (group II, 139 patients), (3) combination of both (group III, 64 patients); and (4) isolated dilatation of the anulus (group IV, 10 patients). One hundred sixty-one patients had isolated mitral disease and 114 had associated aortic or tricuspid valve disease, or both. The hospital mortality rate was 4.0%. Follow-up was 96% complete and totaled 1247.47 patient-years. At 13 years' follow-up, the survival rate was 93.0% +/- 6.8% in group I, 90.0% +/- 6.0% in group II, and 96.6% +/- 4.6% in group III. Freedom from reoperation was 78.1% +/- 21.0%, 83.2% +/- 18.9%, and 79.6% +/- 16.2%, respectively. Freedom from embolism was 94.7% for the whole series. In patients with isolated mitral valve repair, the cumulative morbidity was significantly higher in groups I (6.3 +/- 2.0%/pt-yr) and III 6.3% +/- 1.7%/pt-yr) than in group II (2.5% +/- 0.9%/pt-yr, p less than 0.05). Multivariate analysis identified age and associated tricuspid valve disease as significant predictors of reoperation (p less than 0.01 for both factors). These results suggest that conservative surgery should be used with caution in group I and III patients. In contrast, indications for mitral valve repair should be extended in group II patients. This observation has important clinical implications since, in Western countries, valve prolapse tends to be a major cause of mitral regurgitation.