Of 6,545 patients who had elective coronary angioplasty procedures performed over a 7.5-year period from June 1980 through December 1987, 114 (1.7%) never had symptoms of myocardial ischemia. Exercise-induced silent myocardial ischemia was documented before angioplasty in 94% of these asymptomatic patients. Angioplasty was successful in 87%, whereas emergency coronary artery bypass grafting was required in 4%, and a further 2% had myocardial infarctions after the procedures. The remaining 7% had unsuccessful angioplasty procedures but experienced no in-hospital cardiac events. The follow-up period after hospital discharge averaged 43 +/- 20 months (range 5 to 93). There were no deaths. In the group of 99 patients with initially successful angioplasty procedures the follow-up interval ranged from 5 to 92 months. During that period, 7 patients underwent coronary bypass surgery, 4 patients had myocardial infarction and 30 patients had repeat angioplasty procedures for restenosis. The cumulative probability of event-free survival over 5 years for the group with successful angioplasty was: 100% freedom from death, 95% freedom from myocardial infarction, 87% freedom from myocardial infarction or coronary bypass surgery and 61% freedom from myocardial infarction, coronary bypass surgery or repeat angioplasty. Thus, coronary angioplasty performed in 114 asymptomatic patients, most with exercise-induced silent myocardial ischemia, achieved very good primary success and was accompanied by low cardiac event rates and no deaths over several years of patient follow-up.