Contrast echocardiographic evaluation of early changes in myocardial perfusion after recanalization therapy in anterior wall acute myocardial infarction and their relation with early contractile recovery

Abstract

Temporal changes in myocardial perfusion after recanalization and their relation with functional recovery in patients with acute myocardial infarction (AMI) using intravenous myocardial contrast echocardiography (MCE) have not yet been clarified. To address this issue, 19 patients with first, uncomplicated anterior wall AMI were studied using intravenous MCE within 24 hours of recanalization and before discharge. MCE was performed using harmonic power Doppler. Each asynergic left ventricular (LV) myocardial segment was scored for myocardial perfusion (1 = complete, 0.7 = patchy but >50%, 0.3 = patchy <50%, and 0 = absent) and a regional perfusion index was calculated within the dysfunctioning myocardium. During the day-1 study (11 ± 2 hours from recanalization), the regional perfusion index was 0.4 ± 0.3 and the LV wall motion score index was 1.9 ± 0.2. During the study before discharge (7 ± 4 days from admission), all but 2 patients showed an improvement of either perfusion index (0.6 ± 0.3, p <0.0001) or wall motion score index (1.7 ± 0.4, p <0.0001). Changes in perfusion score from 24-hours to before discharge showed a significant correlation with LV segment contractile recovery at 2-month of follow-up (R 2 = 0.42, 95% confidence interval 0.33 to 0.50, p <0.0001). Thus, our data show that after recanalized AMI, there is a significant amount of microvascular obstruction that recovers in the days after, and the extent of this perfusion improvement appears to be related with early myocardial contractile recovery. Our data provide clinical evidence for a transient microvascular dysfunction after successfully recanalized AMI.