Clinical outcome and left ventricular remodeling in AMI patients with insufficient myocardial reperfusion after recanalization

Abstract

Myocardial contrast echocardiography (MCE) is effective in predicting myocardial viability and functional recovery on a segmental level in patients with acute myocardial infarction (AMI). In this study, we investigated whether insufficient myocardial reperfusion plays an important role in left ventricular (LV) remodeling and functional recovery in patients with thrombolysis in myocardial infarction (TIMI) flow grade 3 and corrected TIMI frame count (CTFC) < 40 after recanalization of the infarct-related artery. Patients underwent intracoronary injection of microbubbles for echocardiographic assessment of myocardial microvascular perfusion, wall motion score, LV volume and ejection function (EF) at baseline, 30 minutes, one month and six months after recanalization. The patients with MCESI < 1 were considered to have insufficient myocardial reperfusion (group A, n=11), while the patients with MCESI≥1 were considered to have sufficient myocardial reperfusion (group B, n=47) after AMI recanalization. The wall motion score index (WMSI) and the left ventricular ejection fraction (LVEF) showed significant improvement at 1 month and 6 months in group B, but only at six months in group A. Left ventricular end-systolic and end-diastolic volumes (LVESV and LVEDV) were also significantly decreased at one and six months in group B. WMSI, LVESV, LVEDV and LVEF were significantly improved in group B in comparison with group A at one month and six months (P < 0.01). By six months, significant correlations were seen in all patients between MCESI and changes in LVESV, LVEDV and LVEF at 6 months. Similar correlations were observed between the myocardial regional blood flow (Q) and changes in LVESV , LVEDV and LVEF. Insufficient myocardial reperfusion was a strong independent predictor of LV remodeling and functional recovery in AMI patients with TIMI flow grade 3 and CTFC < 40 after recanalization. MCE has important additional value for prognosis and risk assessment in patients with acute myocardial infarction following recanalization.