The aim is to find the optimal management of patients with acute myocardial infarction with ST elevations (STEMI) treated by PPCI who have at least one significant stenosis of non-culprit coronary artery. The primary endpoint of the study will be incidence of combined endpoint of all cause mortality, nonfatal myocardial infarction and stroke during the follow up of 24 months in group of patients treated with staged revascularization (PCI or CABG) in comparison with patients treated conservatively.