This study was to determine whether coronary flow reserve (CFR) of infarct related artery is related to the microvascular perfusion status in the infarct zone determined by myocardial contrast echocardiography (MCE) immediately after successful revascularization in patients with acute myocardial infarction and to the presence of non-contractile myocardium at follow-up.

CFR was measured immediately after successful revascularization in 21 patients 5±2 days after acute myocardial infarction. Then, myocardial perfusion status was evaluated by MCE. Myocardial opacification index (MOI) was calculated as the ratio of sum of reperfusion area to total risk area of infarct-related artery. Follow-up transthoracic echocardiography was performed 1 month after infarction.

CFR was correlated with myocardial opacification index immediately after successful revascularization (r=0.79, p<0.001). CFR was significantly higher in patients with MOI score of 1 than in patients with MOI score smaller than 1 (2.15±0.29 vs 1.52±0.27, p<0.05), and higher but insignificantly in patients without non-contractile segments than in patients with (1.83±0.46 vs 1.63±0.4, p>0.05).

CFR may be used to determine the microvascular perfusion status of the myocardium in the infarct zone. CFR immediately after successful revascularization seems to be associated more closely with myocardial perfusion status determined by MCE at that time than whether the non-contractile myocardium is presence or not after 1 month.