Introduction: To evaluate in women and men over 40 years with acute myocardial infarction with ST-segment elevation (STEMI) the features related to cardiovascular risk (CV), time from the symptom onset to hospitalization, type of coronary culprit lesions and lack of efficiency of interventional revascularization at patients (pts.) in whom primary percutaneous transluminal coronary angioplasty (PTCA) was performed. Methods: 86 pts. over 40 years, 20 female (23%) (GrF) and 66 men (77%) (GrM) with STEMI underwent emergency coronary angiography. In 78 pts. was performed primary PTCA (90.6%), in 4 pts. rescue PTCA (4.65%) and in 4 pts. was indicated surgical revascularization (4.65%). The two groups were compared for demographics data, CV risk factors, time of symptom onset to hospitalization, ECG location of STEMI, and type of culprit lesion. Some parameters were comparated in patients with efficient vs inefficient myocardial perfusion aft er primary PTCA. Blush 1 has considered as a marker of inefficient myocardial perfusion. Statistics performed with SPSS 20, using comparisons between not homogeneous groups and bivariate correlations. Statistical significance was p < 0.05. Results: In GrF vs. GrM the average values were: for age 66.9/48.5 years (p = 0.001), time symptom onsethospitalization 9.7/5.4 hours (p = 0.04), number of CV risk factors 4/3.4 (p = 0.01). Significant differences in GrF vs. GrM were found regarding the incidence of diabetes mellitus (DM) 45/19% (p = 0.02), obesity 45/18% (p = 0.04), procoagulant state 45/12% (p = 0.01) and prevoius diagnosed CAD 65/30% (p = 0.005). The types of coronary culprit lesions in GrF vs. GrM were thrombosis 5/22% (p = 0.001), thrombus on atherosclerotic plaque 70/50% (p = 0.02) and atherosclerotic plaque 25/27% (p = 0.7). Blush 1 incidence in GrF vs GrM was 31/18% (p = 0.03), correlated with DM (p = 0.04) and previously diagnosed CAD (p = 0.001) in female, and with ECG anterior location of STEMI and atherothrombotic culprit lesions in men (p = 0.02). Conclusions: The women with STEMI were significantly older than the men, the women come later to hospital, had significantly more CV risk factors and were significantly more oft en diagnosed with diabetes mellitus, obesity, procoagulant state and previous CAD than the men. Coronary obstruction by thrombus on atherosclerotic plaque occurred significantly more frequently in women and by thrombosis in men. Ineffective myocardial perfusion post-PTCA was more common in women and correlated with the presence of diabetes and of previously diagnosed CAD.