BACKGROUND.: Although techniques for percutaneous coronary intervention (PCI) have improved, patients with PCI of more vessels may still have an increased risk. We performed a prospective observational study evaluating the differences between multivessel and single-vessel procedures according to postprocedural troponin T (TnT) elevation and events during follow-up. METHODS.: The study included 713 patients without elevated TnT (<0.05 ng/ml) before PCI. Primary endpoint was the combined endpoint of death, myocardial infarction, stroke, repeat coronary angiography and readmission for anginal symptoms during the mean follow-up of 10.9 months. RESULTS.: TnT after PCI was elevated in 150 patients (21%) and was significantly associated with an increased incidence of the primary endpoint (RR 1.55, 95% CI 1.01 to 2.38). PCI of more than one vessel was performed in 146 patients (20%). These patients more often had increased TnT levels after the procedure (31.5 vs. 18.3%, p=0.001) and an increased incidence of the primary endpoint during follow-up (28 vs. 19%, p=0.01). After multivariable analysis, multivessel PCI was a statistically significant predictor of postprocedural TnT increase (OR 1.90, 95% CI 1.17 to 3.06). Multivessel PCI was also associated with an increased risk of the primary endpoint (OR 1.73, 95% CI 1.18 to 2.52), but after adjusting for multivessel disease this association was not statistically significant (OR 1.42, 95% CI 0.92 to 2.19). CONCLUSION.: Elective PCI of more vessels in one session is, in comparison with single-vessel PCI, more often associated with postprocedural troponin T rise and a (nonsignificantly) higher incidence of cardiac events during follow-up. Whether staged PCI is associated with less morbidity has to be assessed. (Neth Heart J 2007;15:178-83.).