From June 1986 to June 1991, percutaneous balloon valvuloplasty was performed in 43 patients with severe symptomatic aortic stenosis. Their age ranged from 52 to 81 years (mean 69). The retrograde approach was used in 34 and the transseptal technique in the remaining 9. One patient died from severe tamponade, another developed a large cerebral infarct and the procedure failed in a third. The procedure was considered successful in the remaining 36 patients. Cardiac output increased from 3.5 +/- 0.6 to 4.7 +/- 0.7 l/min, (p < 0.01) and aortic valve area from 0.53 +/- 0.21 to 0.97 +/- 0.2 cm2 (p < 0.01). After a follow up period of 24 +/- 9 months 3 patients, all with initially poor results, died. 10 of 19 patients with adequate initial results experimented a deterioration of functional class. The other 9 patients have preserved the initial improvement obtained with dilatation. Thus percutaneous aortic valve dilatation in adults with severe aortic stenosis is risky and of limited clinical value.