Acute and chronic phase myocardial tissue characteristics in non ST-elevation myocardial infarction in dependence of early versus delayed revascularisation assessed by cardiac magnetic resonance imaging

Abstract

Background According to current guidelines, an adequate timeframe for revascularisation in the setting of acute non-ST-elevation myocardial infarction (NSTEMI) is considered by current guidelines as being up to 72 hours after symptom onset. Soon after myocardial infarction, changes take place in the affected myocardium that can be visualized and measured by cardiac magnetic resonance imaging (CMR). Aim of the present study was to compare tissue characteristics in patients with NSTEMI that underwent early vs. delayed revascularisation. Therefore, myocardial tissue characteristics were evaluated in the acute and chronic phase of reperfused NSTEMI patients and the findings were correlated to the particular symptom-to-reperfusion time. Methods In 53 patients presenting with NSTEMI, CMR imaging was performed in addition to invasive coronary angiography. The patients were examined on a 1.5 T wholebody scanner using a 32-channel phased-array surface coil. Left-ventricular volumes were assessed by a standard steady-state free-precession sequence. Myocardial edema was evaluated using a 3D T2-weighted blackblood fat-saturated spin-echo sequence. Microvascular obstruction and late gadolinium enhancement were measured by a 3D phase-sensitive inversion-recovery gradient echo sequence about 12 minutes after intravenous administration of gadolinium based contrast agent. CMR imaging was conducted shortly after coronary revascularisation and about 90 days later at follow-up. Results were gained by two experienced readers in consensus.