Over an eleven year period, 57 patients under 35 years of age underwent percutaneous transluminal coronary angioplasty (PTCA). The features of the study population were: 55 men and 2 women, average age 32 +/- 3 years; unstable angina in 30%, previous myocardial infarction in 53%, average left ventricular ejection fraction 59 +/- 12%, single vessel disease in 84%. A total of 63 vessels were dilated. The primary success rate was 81% (72% in the first 29 patients compared with 89% in the latter 28 patients, p = 0.1). The following complications were observed: peri-procedural infarction (4 cases), emergency coronary bypass surgery (4 cases), no fatalities. During follow-up (average 6 +/- 3 years), of the 43 patients who underwent control coronary angiography in the last 6 months, 14 (33%) had angiographic restenosis. The long-term outcome was marked by 5 coronary bypass operations (3 for restenosis, 1 after failure of PTCA and 1 for progression of the coronary disease), 8 PTCAs for a new lesion due to progression of the coronary disease, 2 deaths and 2 non-lethal infarctions. The 10 year survival was 96 +/- 3% and the survival rate without cardiac events (infarction, surgical revascularisation or repeat PTCA) was 62 +/- 10% at 10 years. Of the 54 survivors, 50 (92%) have no angina, and 44 (81%) continue to take antiischaemic drug therapy. Of the 50 patients who were in full employment, 37 (74%) have gone back to full-time working and 8 (16%) have taken part-time jobs. (ABSTRACT TRUNCATED AT 250 WORDS)