Background: The purpose of this study was to investigate the associations between variants of a promoter polymorphism of the endothelial nitric oxide synthase (eNOS) gene and clinical outcomes in acute ST-segment elevation myocardial infarction (STEMI) patients after a successful primary percutaneous coronary artery intervention (PCI).
 Methods: 177 patients with acute STEMI, 82 patients with angiographically proven stable coronary artery disease, and healthy volunteers were included in the study. The primary end-point was a combined event (follow-up major adverse cardiac events –MACEs and hospitalization) that occurred within 6-month of the discharge from the hospital.
 Results: The combined end-point was determined in 72 patients from the entire acute STEMI population (40.6%), including 24 events for 786TT genotype, 23 events for 786TC genotype and 25 events for 786CC genotype. Kaplan-Meier curves demonstrated that acute STEMI patients with 786CC eNOs genotype had lower MACEs free accumulation when compared to those with 786TC and 786TT eNOs genotypes at 6-month follow up period (Log-rank p < 0.001). Multivariate Cox regression analyses identified 786CC in eNOs gene as an independent predictor of clinical outcomes in STEMI after PCI.
 Conclusions: the 786CC polymorphism in eNOs gene is an independent predictor for clinical outcomes after a successful primary PCI in acute STEMI.