To identify factors that predict a second restenosis after repeat percutaneous transluminal coronary balloon angioplasty (PTCA), the records of 196 consecutive patients undergoing redilation for treatment of a first restenosis were reviewed. Repeat PTCA was successful in 181 (92%) of these patients. After a successful second PTCA, 47 patients (26%) developed a second restenosis (recurrent restenosis group, group 1) and 134 (single restenosis group, group 2) did not. The 2 patient groups were compared with respect to clinical, angiographic and procedural factors at second PTCA. Univariate correlates of a second restenosis were younger age (54 +/- 10 vs 57 +/- 9 years, p less than 0.05), interval less than 60 days between initial PTCA and recurrence of anginal symptoms (55% of patients in group 1 vs 25% in group 2, p = 0.001), a greater number of inflations (6.3 +/- 4.2 vs 4.4 +/- 2.5, p less than 0.005) and a shorter maximal balloon inflation time (49 +/- 26 vs 69 +/- 36 seconds, p = 0.0006). With multivariate analysis, the 2 factors that emerged as independent predictors of recurrent restenosis were recurrence of symptoms less than 60 days after initial PTCA (p less than 0.004) and a greater number of inflations (p less than 0.04). These data suggest that younger age and rapid recurrence of anginal symptoms after first PTCA predict an increased likelihood that a second restenosis will occur after repeat PTCA and that certain procedural factors, in particular the greater number of balloon inflations and a shorter maximal balloon inflation time, may play an important role in the development of recurrent restenosis.