Mitral valve replacement after closed mitral commissurotomy.

Closed mitral commissurotomy (CMC) was performed at the National Heart Institute in 303 patients (73% women, 27% men; mean age 40 years) with acquired isolated mitral stenosis between 1954 and 1980. The average mean mitral valve gradient decreased from 14.2 +/- 0.4 to 5.3 +/- 0.4 mm Hg (p less than 0.001), and mitral valve area index increased from 0.7 +/- 0.03 to 1.4 +/- 0.9 cm2/m2 (p less than 0.001). The perioperative mortality was 2%. Ninety-two percent of patients improved one or more functional classes after CMC. Actuarial survival was 95%, 82% and 70% at 5, 10 and 15 years after CMC, respectively. Fifty-four patients (18%) required mitral valve replacement (MVR) a mean of 9.6 years after commissurotomy (range 1-26 years). Before CMC, factors associated with later MVR included preoperative functional class, calcification of the mitral valve, and the absence of an opening snap. After CMC, poor functional improvement, congestive heart failure, atrial fibrillation, and the necessity for a repeat CMC were associated with late MVR. Catheterization after CMC showed that patients who later required MVR had a smaller decrease in left atrial pressure (p less than 0.001), more mitral regurgitation (p less than 0.001), and were more likely to have pulmonary hypertension (p less than 0.05). The indications for MVR were residual stenosis with or without mild mitral regurgitation in 33 patients (61%), restenosis in 15 (28%), and moderate-to-severe regurgitation in six (11%). Perioperative mortality for valve replacement was 13%. Among survivors, 88% improved at least one functional class after valve replacement. Actuarial survival was estimated to be 95% at 5 years and 74% at 10 years after MVR. This study confirms that CMC provides excellent long-term hemodynamic and clinical improvement in appropriately selected patients. When symptomatic deterioration occurs late after CMC, MVR restores clinical and hemodynamic improvement in many patients. CMC continues to be performed at the National Heart Institute in selected patients with acquired mitral stenosis.