AimTo investigate the characteristics of lesion of infarct-related artery (IRA) at different stages after acute myocardial infarction.MethodsThe data of 1 524 patients with myocardial infarction (MI) who underwent coronary angiography (CAG) from June 2005 to June 2011 were retrospectively analyzed.All the patients were divided into four groups according to the time between onset and CAG: Group A: patients with ST-segment elevation MI (STEMI) who received emergency CAG within 24 hours; Group B: patients who received selective CAG between 1 and 2 weeks after the onset of STEMI; Group C: patients with old myocardial infarction; Group D: patients who received CAG within 3 days after the onset of non-ST-segment elevation MI (NSTEMI).The incidences of total occlusion of IRA in all groups were investigated and calculated.ResultsThe incidence of total occlusion of IRA in group A (82.9%,651/785) was significantly higher than group B (56.4%,185/328), group C (72.7%,125/172), and group D (55.2%,132/239) (p<0.001).There were also significant differences between group C and group B,D (p<0.01).ConclusionsThe incidence of total occlusions of IRA decreased sharply in two weeks after acute myocardial infarction (AMI), and almost half of the patients achieved blood flow of TIMI (thrombolysis in myocardial infarction) grade 2 to 3 in IRA.A low rate of total occlusion of IRA was found in the patients with NSTEMI, which may account for non-ST-segment elevation.