Between November 1980 and November 1985, 54 patients ages greater than or equal to 70 years underwent percutaneous transluminal coronary angioplasty for unstable angina, defined as recent-onset (less than 1 month) angina, new onset of rest angina (greater than or equal to 2 episodes) or accelerating class III or IV angina. In these 20 men and 34 women, disease was 1-vessel in 34 (63%) and multivessel in 20 (37%). The mean (+/- standard deviation) ejection fraction was 0.62 +/- 0.12. Angioplasty was successful in 43 patients (80%). In the 11 unsuccessful cases, emergency coronary artery bypass grafting for acute occlusion was performed in 3 and elective coronary artery bypass surgery in 8. There were no deaths. Two patients (4%) sustained Q-wave myocardial infarctions. The mean duration of follow-up for the total group was 37 months (6 to 73 months). Of the 43 patients with successful dilation, 4 died, 1 had an non-Q-wave myocardial infarction and 8 had symptomatic restenosis (4 underwent successful repeat angioplasty, 1 had repeat percutaneous transluminal coronary angioplasty and then bypass surgery, 1 had repeat bypass surgery alone and 2 had medical therapy). At last follow-up, 3 patients had stable class III or IV angina and 31 patients (72%) were angina-free.