An analysis of percutaneous transluminal angioplasty of the coarctation of the aorta in adults was evaluated in a cooperative study of the German Working Group of Angioplasty of the German Society of Cardiology. Dilation was performed in 18 patients with a mean age of 26 years (14-49 years). The success rate (gradient less than or equal to 20 mm Hg) was 78% regarding peak to peak gradient, 89% regarding mean gradient. The peak-to-peak gradient decreased from 82 +/- 16 mm Hg to 18 +/- 11 mm Hg. The diameter of the aortic isthmus increased from 0.7 +/- 0.3 cm to 1.3 +/- 0.4 cm (p less than 0.01). After six months only one restenosis occurred. The peak-to-peak gradient measured 10 +/- 12 mm Hg, the diameter 1.4 +/- 0.5 cm. In two patients a balloon rupture occurred without rupture-related complications. No patients died, no cross paralysis or aortic rupture occurred. In three of seven patients with trans-esophageal echocardiographic monitoring a small intimal flap was found; in one patient a media dissection occurred leading to a 15-min period of chest pain and spontaneous healing. In another patient successful dilation was controlled by acute control aortography and computer tomography. After discharge severe chest pain developed. A subtraction angiography of the aorta was negative. Six months later a biplane aortography of the distal thoracic aorta confirmed the diagnosis of aortic dissection type III DeBakey, previously diagnosed by transesophageal echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)