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Objective: The purpose of this study was to review the risk-benefit ratio of mitral valve repair in patients with severe mitral regurgitation and no or mild symptoms., Methods: From January 1989 to December 1994, 584 patients were operated on for mitral regurgitation. Of these, 175 patients were in New York Heart Association class I or II with grade 3 to 4 isolated chronic mitral regurgitation. They comprise our study population. Mean age was 51.3 +/- 14.3 years. Principal causes of mitral regurgitation were degenerative in 128 (73%) and rheumatic in 26 patients (15%). Leaflet prolapse was the mechanism responsible for regurgitation in 152 patients (86%). Mitral valve repair was performed in 174 patients, and one patient required initial valve replacement. Mean follow-up was 34.3 +/- 18.8 months., Results: Three patients died, for an overall mortality of 1.7%. Five patients were reoperated on, for an actuarial freedom from reoperation of 97.0% +/- 0.8% at 5 years. Actuarial freedom from thromboembolism and endocarditis was 96.3% +/- 1.7% and 99.4% +/- 0.6%, respectively, for an event-free survival of 91.0% +/- 2.0% at 5 years. Left atrial diameter decreased from 54.3 +/- 11.6 mm to 43.6 +/- 10.5 mm (p < 0.001). Left ventricular end-systolic and end-diastolic diameters decreased from 40.0 +/- 6.8 mm and 64.8 +/- 7.0 mm to 34.6 +/- 6.7 mm (p < 0.001) and 52.7 +/- 7.4 mm (p < 0.001), respectively. Mean residual mitral regurgitation was 0.44 +/- 0.6., Conclusion: Mitral valve repair for chronic mitral regurgitation in patients having mild or no symptoms was performed with low mortality and morbidity, good valve function, and preserved late left ventricular performance. Early repair may be advocated on the basis of severity of regurgitation and valve repairability, regardless of symptoms.

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.