Clinical and echocardiographic data of 547 consecutive patients (mean age, 31.5 years) undergoing mitral balloon valvuloplasty with follow-up of 1.5-19 years, were analyzed. Immediately after valvuloplasty, mitral valve area increased significantly from 0.92 +/- 0.17 to 1.95 +/- 0.29 cm(2). Restenosis occurred in 169 (31%) patients; it was less common (20%) in those with a mitral echocardiographic score </=8. Actuarial freedom from restenosis at 10, 15, and 19 years was 78% +/- 2%, 52% +/- 3%, and 26 +/- 4%, respectively, and significantly higher in patients with echocardiographic scores </=8: 88% +/- 2%, 67% +/- 4%, and 40% +/- 6%, respectively. Event-free survival at 10, 15, and 19 years was 88% +/- 2%, 60% +/- 4%, and 28% +/- 7%, respectively, and significantly higher in patients with echocardiographic scores </=8: 92% +/- 1%, 70% +/- 4%, and 42% +/- 7%, respectively. Multivariate analysis identified echocardiographic score </=8 and post-procedure valve area </=1.8 as predictors of restenosis, and echocardiographic score>8 and preexisting atrial fibrillation as predictors of combined events. Valvuloplasty provides excellent results in selected patients with mitral stenosis. The long-term outcome can be predicted from the baseline characteristics of the mitral valve.