Although transluminal coronary angioplasty is now acknowledged as an effective treatment for coronary artery disease, the long-term outcome of patients treated by this method is still under evaluation. A french multicenter trial was set up and the long-term efficacy of transluminal coronary angioplasty was assessed in 546 patients undergoing the procedure before the 31/3/83. 380 initial successes (69 p. 100) were followed up for a period ranging from 6 to 48 months (average 19.9 +/- 10.4 months). A control coronary angiography was carried out in 88 p. 100 of cases. Restenosis (loss of over 50 p. 100 of initial angiographic improvement) was observed in 27 p. 100 of cases. Including the repeat procedures, the patency rate of the dilated vessels was 82 p. 100. Progression of atherosclerosis on another coronary artery was observed in 1.3 p. 100 of cases. After transluminal coronary angioplasty, 72 p. 100 of patients remained improved, 11 p. 100 underwent repeat angioplasty, 8 p. 100 underwent coronary bypass surgery, 1.3 p. 100 suffered myocardial infarction and 1.3 p. 100 died. Restenosis was associated with recurrence of angina pectoris in 90 p. 100 of cases (within 3.3 +/- 1.6 months) and a positive exercise stress test in 87 p. 100 of cases. Recurrence of angina due to progression of disease on the dilated vessel was observed in 24.2 p. 100 of cases; repeat transluminal coronary angioplasty was carried out for this indication in 38 p. 100 of cases, coronary bypass in 34.8 p. 100 and medical treatment was continued in 27.2 p. 100 of cases.(ABSTRACT TRUNCATED AT 250 WORDS)