This paper attempts to determine limitations and indications of performing a second balloon aortic valvuloplasty procedure (BAV2) because of restenosis, which is the major limitation of this technique. From September 1985 to December 1989, 357 patients underwent a primary BAV (BAV1) and 67 patients had a BAV2. Forty-two patients (group A) had repeat catheterization because they were markedly symptomatic 11 +/- 7 months after BAV1. Twenty-five patients (group B) came from a group of 73 patients who had been systematically scheduled for repeat catheterization in order to evaluate the hemodynamic restenosis rate 8 +/- 3 months after BAV. At time of BAV2 most of the patients of group A were severely disabled. Comparison of pre-BAV2 gradient and aortic valve area with pre-BAV1 measurements showed in a slightly less severe degree of aortic stenosis in group A and in group B with any difference in cardiac index and ejection fraction. Immediately following BAV2, the gradient decreased from 72 +/- 22 to 33 +/- 15 mm Hg (P less than 0.001) and aortic valve area increased from 0.56 +/- 0.18 to 0.85 +/- 0.28 cm2 (p less than 0.001) in group A. In group B, gradient decreased from 68 +/- 15 to 33 +/- 15 mm Hg (p less than 0.001) and aortic valve area increased from 0.70 +/- 0.16 to 0.90 +/- 0.25 cm2 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)