Objectives: The present study tested the hypothesis that pretreatment with metformin decreases postprocedural myocardial injury and improves clinical outcomes in metabolic syndrome patients following percutaneous coronary intervention (PCI).Methods: We enrolled 152 metabolic syndrome patients with no prior history of metformin treatment. Patients scheduled for elective coronary intervention were randomized to the metformin or control group 7 days before the procedure. Creatine kinase-MB (CK-MB) and troponin I levels were measured at baseline and 8 and 24 h after the procedure, and clinical outcomes were monitored for 1 year. Results: Post-PCI myocardial injury as indicated by CK-MB elevation (14.5 vs. 32.9%, p = 0.008) and troponin I elevation (14.5 vs. 34.2%, p = 0.005) was significantly lower in the metformin group than in the control group. Postprocedural peak values of CK-MB (2.70 +/- 4.30 vs. 6.29 +/- 8.03 ng/ml, p < 0.001) and troponin I (0.02 +/- 0.05 vs. 0.07 +/- 0.10 ng/ml, p = 0.001) were also significantly lower in the metformin group than in the control group. At 1 year, the composite endpoint of death from any cause, post-PCI myocardial infarction (MI), MI after PCI hospitalization or ischennia-driven target lesion revascularization occurred in 7.9% of metfor-min-treated patients and 28.9% of controls (hazard ratio 0.25, 95% CI 0.10-0.62, log rank p = 0.001). Conclusions: A 7-day nnetformin pretreatment regimen (250 mg 3 times a day) significantly reduces postprocedural myocardial injury and improves 1-year clinical outcomes in metabolic syndrome patients undergoing PCI. (C) 2013 S. Karger AG, Basel