The initial and late outcome of coronary angioplasty was studied in 148 patients less than 40 years of age (mean 36.4 +/- 3). Angioplasty was performed on a single vessel in 70% of patients and on multiple vessels in 30%; it was performed on a totally occluded vessel in 20%. Angioplasty was successful in 90.5% of patients, unsuccessful but uncomplicated in 7.4% and complicated by myocardial infarction in 0.7%, emergency bypass surgery in 0.7% and death in 0.7%. At late (mean 3.7 +/- 3 years; range 0.5 to 11.5) follow-up study after successful angioplasty, 94% of patients were alive, 79% were free of angina and 85% had returned to work; late myocardial infarction occurred in 4%. Actuarial survival at 5 years was 95%, and 85% of patients were free from death, infarction or bypass surgery. A second angioplasty was performed in 29 patients (22%) (mean 6.1 +/- 8.4 months) and was successful in 27 (93%), with no deaths. Elective coronary bypass surgery was performed in 8.5% of patients, with perioperative infarction in 9% and no deaths. By univariate analysis, late death was more likely to occur in hypertensive patients (15% versus 2.5%; p less than 0.01) and diabetic patients (21.4% versus 3.6%; p less than 0.01). Cox proportional hazard regression analysis identified hypertension (p = 0.007) and diabetes (p = 0.04) as independent time-related predictors of subsequent death. Thus, early and late results after coronary angioplasty in young adults are favorable, but certain risk factors are important predictors of outcome. Late revascularization procedures (repeat angioplasty or surgery) for restenosis or disease progression are common.