The long-term clinical and angiographic outcome of 76 elderly (> or = 65 years) patients undergoing coronary angioplasty (PTCA) (83 lesions attempted) for post-infarction angina (PIA) (group I) was compared with that of 83 elderly patients undergoing PTCA (105 lesions) for stable angina (group II). Age (70 +/- 4 years), gender (70% male) and major demographic variables were similar in both groups. The mean left ventricular ejection fraction was 56 +/- 14% in group I vs 67 +/- 14% in group II (P < 0.01). In group I, PTCA was performed more frequently for lesions located in the right coronary artery (35% vs 18%, P < 0.01) and less frequently in the left circumflex artery (12% vs 26%, P < 0.05). Although the percentage of lesions with thrombi was higher in group I (16% vs 2%, P < 0.001), the rate of angiographic success was similar in both groups: 94% (78/83 lesions) in group I vs 93% (98/105) in group II (ns). PTCA was successful in 67 patients (88%) in group I and in 74 (89%) in group II (ns). The rate of major complications was also similar in both groups (4%). Restenosis occurred in 36% vs 31% of the lesions in groups I and II respectively (mean time to angiographic follow-up 7 +/- 2 months) (proportion of cases with a repeat angiography: 79% in group I and 72% in group II). Restenosis was asymptomatic in 57% vs 50% of the patients respectively.(ABSTRACT TRUNCATED AT 250 WORDS)