Characterization of the peri-infarct zone by contrast-enhanced cardiac magnetic resonance imaging is a powerful predictor of post-myocardial infarction mortality

Background - Accurate risk stratification is crucial for effective treatment planning after myocardial infarction (MI). Previous studies suggest that the peri-infarct border zone may be an important arrhythmogenic substrate. In this pilot study, we tested the hypothesis that the extent of the peri-infarct zone quantified by contrast-enhanced cardiac magnetic resonance (CMR) is an independent predictor of post-MI mortality. Methods and Results - We studied 144 patients with documented coronary artery disease and abnormal myocardial delayed enhancement (MDE) consistent with MI. A computer-assisted, semiautomatic algorithm quantified the total infarct size and divided it into the core and peri-infarct regions based on signal-intensity thresholds (> 3 SDs and 2 to 3 SDs above remote normal myocardium, respectively). The peri-infarct zone was normalized as a percentage of the total infarct size (% MDEperiphery). After a median follow-up of 2.4 years, 29 (20%) patients died. Patients with an above-median % MDEperiphery were at higher risk for death compared with those with a below-median %MDEperiphery (28% versus 13%, log-rank P < 0.01). Multivariable analysis showed that left ventricular systolic volume index and % MDEperiphery were the strongest predictors of all-cause mortality (adjusted hazard ratio [HR] for % MDEperiphery, 1.45 per 10% increase; P = 0.002) and cardiovascular mortality (adjusted HR, 1.51 per 10% increase; P = 0.009). Similarly, after adjusting for age and left ventricular ejection fraction, % MDEperiphery maintained strong and independent associations with all-cause mortality (adjusted HR, 1.42; P = 0.005) and cardiovascular mortality (adjusted HR, 1.49; P = 0.01). Conclusions - In patients with a prior MI, the extent of the peri-infarct zone characterized by CMR provides incremental prognostic value beyond left ventricular systolic volume index or ejection fraction. Infarct characteristics by CMR may prove to be a unique and valuable noninvasive predictor of post-MI mortality.