Despite excellent results as a bail-out procedure for the management of abrupt closure after balloon angioplasty and the potential beneficial effects on restenosis after angioplasty, intracoronary stenting is limited, especially by subacute stent thrombosis. In 100 consecutive patients with intracoronary implantation of 118 Palmaz-Schatz stents, 10 patients (10%) developed subacute stent thrombosis during their hospital course 3 to 9 days after implantation. Therapy included intravenous thrombolysis, mechanical recanalization by balloon angioplasty, and emergency bypass surgery. Although successful recanalization was maintained in eight of nine nonsurgically treated patients within 2 hours after the onset of symptoms, seven patients developed myocardial infarction, with two patients having Q wave myocardial infarction and five patients having non-Q wave myocardial infarction. By univariate analysis, several variables could be identified as risk factors for the development of subacute stent thrombosis: bail-out implantations (odds ratio: 6.42; 95% confidence interval: 1.53 to 26.38; p = 0.007), unstable angina (12.32; 1.50 to 101.37; p = 0.006), long (5.44; 1.31 to 22.65; p = 0.015) and complex (type C) lesions (8.17; 1.93 to 34.50; p = 0.002) with large plaque areas (9.85; 1.96 to 44.51; p = 0.002), symptomatic postangioplasty dissections (4.36; 1.10 to 16.90; p = 0.029), incomplete wrapping of the dissection after stenting (6.50; 1.10 to 42.30; p = 0.039), and vessel irregularities distal to the stented segment (21.70; 4.12 to 113.18; p < 0.001). These variables, except the variable large plaque area, were confirmed as independent predictors of subacute stent thrombosis by a stepwise multivariate logistic regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)