The aim of this prospective study was to determine the value of quantitative exercise thallium-201 scintigraphy for predicting short-term outcome in patients after percutaneous transluminal coronary angioplasty (PTCA). Quantitative exercise thallium-201 scintigraphy was performed 2.2 +/- 1.2 weeks after successful PTCA in 68 asymptomatic patients, 64 (94%) of whom had class III or IV angina before the procedure. Clinical follow-up was obtained in all patients at a mean of 10 +/- 2 months and all were followed for at least 6 months; 45 patients (66%) remained asymptomatic during follow-up and 23 (34%) developed recurrent class III or IV angina at a mean of 2.6 +/- 1.2 months. Multivariate analysis of 22 clinical, angiographic and exercise test variables revealed that thallium-201 redistribution, any thallium scan abnormality, presence of a distal stenosis and treadmill time were the only significant predictors of recurrent angina after PTCA. Using a stepwise discriminant function model, thallium-201 redistribution was the only significant independent predictor. Despite its prognostic value relative to other variables as a predictor, thallium redistribution at 2 weeks after PTCA was only detected in 9 of the 23 patients (39%) who subsequently developed recurrent angina, although only 2 of the 45 patients (9%) who remained asymptomatic during follow-up demonstrated thallium-201 redistribution at the time of early testing. After repeat angiography was performed in 17 of the 23 patients with recurrent angina, 14 (82%) demonstrated restenosis and 3 (18%) had worse narrowing distal to or remote from the site of dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)