The impact of coronary stenting on microvascular circulation in the infarct area was compared with that of balloon angioplasty in 94 patients with acute myocardial infarction (AMI) who underwent coronary revascularization within 6 h of onset: 49 patients were treated with balloon angioplasty alone, and 45 were treated with coronary stenting. Microvascular circulation after revascularization was assessed by Thrombolysis in Myocardial Infarction (TIMI) flow grade analysis and ST segment analysis. TIMI flow grade was assessed on the final angiographic image after coronary intervention, and the ST segment was assessed on the 12-lead electrocardiogram recordings just before revascularization and on return to the coronary care unit. The distributions of TIMI flow grade and change in ΣST (5.1±10.8 vs 5.1±9.9 mm) were similar between the 2 groups. Predischarge left ventricular ejection fraction (54±14 vs 54±15%) and in-hospital outcome were also similar between the 2 groups. The data suggest that coronary stenting did not influence microvascular circulation (improvement or detriment) in patients with reperfused AMI. (Circ J 2002; 66: 917 - 920)