Surgical treatment of asymptomatic and mildly symptomatic mitral regurgitation

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.

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.

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.

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.