Cardiac Magnetic Resonance With Edema Imaging Identifies Myocardium at Risk and Predicts Worse Outcome in Patients With Non–ST-Segment Elevation Acute Coronary Syndrome

ObjectivesThe aim of this study was to define the prevalence and significance of myocardial edema in patients with non–ST-segment elevation acute coronary syndrome (NSTE-ACS).BackgroundMost patients with NSTE-ACS undergo angiography, yet not all have obstructive coronary artery disease (CAD) requiring revascularization. Identifying patients with myocardium at risk could enhance the effectiveness of an early invasive strategy. Cardiac magnetic resonance (CMR) can demonstrate edematous myocardium subjected to ischemia but has not been used to evaluate NSTE-ACS patients.MethodsOne hundred consecutive patients with NSTE-ACS were prospectively enrolled to undergo 30-min CMR, including T2-weighted edema imaging and late gadolinium enhancement before coronary angiography. Clinical management including revascularization decision-making was performed without CMR results.ResultsOf 88 adequate CMR studies, 57 (64.8%) showed myocardial edema. Obstructive CAD requiring revascularization was present in 87.7% of edema-positive patients versus 25.8% of edema-negative patients (p < 0.001). By multiple logistic regression analysis after adjusting for late gadolinium enhancement, perfusion, and wall motion scores, TIMI risk score was not predictive of obstructive CAD. Conversely, an increase in T2 score by 1 U increased the odds of subsequent coronary revascularization by 5.70 times (95% confidence interval: 2.38 to 13.62, p < 0.001). Adjusting for peak troponin-I, patients with edema showed a higher hazard of a cardiovascular event or death within 6 months after NSTE-ACS compared with those without edema (hazard ratio: 4.47, 95% confidence interval: 1.00 to 20.03; p = 0.050).ConclusionsIn NSTE-ACS patients, rapid CMR identifies reversibly injured myocardium due to obstructive CAD and predicts worse outcomes. Identifying myocardium at risk may help direct appropriate patients toward early invasive management.