Neutrophil Gelatinase-associated Lipocalin (NGAL) is a acute phase protein which is elevated in conditions like acute kidney injury and myocardial infarction. When a coronary artery is occluded, detrimental changes occur in myocardial vessels. After relief of the occlusion, blood flow to the heart may still be impeded, a phenomenon known as "no-reflow". Data is lacking on factors associated with early detection of patients at risk for this phenomenon, and early stratification of this group seems vital since the no-reflow phenomenon is associated with worse outcomes. The investigators hypothesized that there might be an association between higher NGAL levels and the occurrence of no-flow findings, and that NGAL might serve as a marker of worse prognosis in this population. The investigators also hypothesized that NGAL levels might serve as a marker of early acute kidney injury and that there might be specific patterns of NGAL levels over time in different subsets of patients. The aim of the study is to determine the association between NGAL levels at admission and during the first days after a ST-elevation myocardial infarction, the occurrence of the no-reflow phenomenon, the extent of myocardial damage ascertained by cardiac imaging techniques (echocardiography and cardiac resonance imaging). Data regarding patients' clinical, laboratory, electrocardiogram, coronary angiography and percutaneous coronary intervention, in-hospital and 30-day follow-up after discharge will be recorded.