A dual balloon technique was studied in 16 patients with aortic stenosis in whom results with a single balloon (up to 20 mm, 5.5 cm or 25 mm, 3.0 cm in diameter and length, respectively) were judged to be suboptimal. Dual balloon valvuloplasty was performed using 2 balloons advanced and inflated simultaneously across the stenotic aortic valve orifice. For the group as a whole, the average peak transvalvular gradient was reduced from 79 +/- 8 to 57 +/- 7 mm Hg (mean +/- standard error) using a single balloon (p less than 0.0005), and reduced further to 36 +/- 4 mm Hg using dual balloons (p less than 0.0005 compared with single balloon results). Similarly, calculated aortic valve orifice area was increased from 0.45 +/- 0.04 to 0.57 +/- 0.05 cm2 using a single balloon (p less than 0.0005), and further increased to 0.77 +/- 0.06 cm2 using dual balloons (p less than 0.0005). Dual balloon dilation caused no complications directly attributable to the use of 2 balloons, including no exacerbation of aortic regurgitation. These results suggest that dual balloon valvuloplasty is safe and efficacious in selected patients with aortic stenosis.