Background Rapid recanalization of infarct-related artery (IRA) has become the major target during primary percutaneous coronary intervention (PCI) for patients with ST-elevation myocardial infarction (MI),but strategy for treatment of non-IRA lesions in this setting remains unclear.This study aimed to compare long-term effects between PCI for IRA only and that for both IRA and non-IRA in ST-elevation MI patients with multi-vessel disease.Methods A total of 242 eligible patients with ST-elevation MI and at least two diseased coronary arteries (luminal narrowing≥70%) undergoing primary PCI were included.Of them,149 patients underwent primary PCI for IRA only (group 1),and 93 received primary PCI for IRA followed by elective PCI for non-IRA 7 to 15 days after acute myocardial infarction (AMI) (group 2).Drug-eluting stents (DESs) were deployed in more than 90% of the patients.Results The two groups did not differ with respect to baseline clinical and angiographic characteristics.No significant differences were observed in 12-month clinical follow-up results regarding major adverse cardiac events (11.5% vs 15.1%,P>0.05) and target lesion revascularization (8.1% vs 7.6%,P>0.05) between the two groups.However,patients in group 1 had higher rates of recurrent angina (10.1% vs 2.1%,P<0.05) and depressed left ventricular ejection fraction evaluated by echocardiography (0.56±0.22 vs 0.63±0.25,P <0.05).Conclusion With the use of DESs,complete revascularization with elective PCI for non-IRA after primary PCI may exert a beneficial effect on long-term symptomatology and left ventricular function in patients with ST-elevation MI and multi-vessel disease.