We sought characteristics predictive of the need for operative revascularization subsequent to a successful coronary angioplasty. Through June 1993, 128 patients who had successful percutaneous transluminal coronary angioplasty (PTCA) between January 1982 and March 1989 required subsequent coronary artery bypass grafting (CABG) at our hospital. These cases were matched with 128 controls who had a successful PTCA but did not require subsequent CABG. Controls were matched to cases by the date of their initial PTCA. Before initial PTCA there were no differences between the cases and controls in terms of age, sex, prior myocardial infarction, ejection fraction, duration of anginal symptoms, hypertension, hyperlipidemia, family history, or obesity (all not significant). A greater number of cases had diabetes (35 versus 18; p = 0.009). Angiography before initial PTCA revealed that cases had a greater mean number of total lesions (4.1 versus 3.3; p = 0.002) and a higher incidence of left anterior descending and circumflex artery stenoses of 70% or greater (98 versus 75 and 57 versus 34, respectively; p = 0.006). The mean number of lesions successfully dilated was greater in cases (2.4 versus 1.7; p = 0.0001). Cases had CABG at a mean interval of 16.7 +/- 23 months. There were 17 late deaths among cases and 9 among the controls at a mean of 38.6 +/- 30 months. The survival probability at 5 years was 94.5% for controls and 87.9% for cases (p = 0.048). Initial revascularization by PTCA is followed by CABG at a brief interval in a subset of patients who have markers of more severe disease than do patients who do not require early CABG.(ABSTRACT TRUNCATED AT 250 WORDS)