Balloon valvuloplasty has been shown to be an effective treatment for adults with aortic stenosis, typically providing a 50 to 80% increase in aortic valve area and marked improvement in exertional dyspnea, angina and syncope. However, the duration of this hemodynamic and clinical improvement is uncertain. Forty-two patients were followed for 10.2 +/- 0.5 months. Balloon valvuloplasty caused dramatic immediate reduction in the number of patients with moderate or severe dyspnea (80 to 14%), moderate or severe angina (39 to 2%) and syncope (30 to 2%). Furthermore, this improvement in symptoms continued for the duration of the follow-up period in most patients. Echocardiographic aortic valve mean gradient and area determined at 3-month intervals, however, showed a trend toward or return to prevalvuloplasty levels by 9 months' follow-up in 13 of 25 patients (52%), whereas 12 of 25 patients showed no deterioration in their hemodynamic parameters. This trend toward restenosis was accompanied by symptomatic deterioration in 5 of 13 patients (38%). This tendency toward restenosis in greater than 50% of patients by 9 months underscores the need for further technical improvements if balloon valvuloplasty is to be widely applied. Even with these limitations, however, balloon valvuloplasty seems to provide a significant improvement in actuarial survival compared with the natural history of elderly patients with severe aortic stenosis.