Does the extent of the peri-infarct zone measured by contrast-enhanced CMR predict mortality in patients with prior myocardial infarction?
The extent of the peri-infarct zone measured by contrast-enhanced CMR provides incremental prognostic value for mortality beyond left ventricular ejection fraction and systolic volume index in patients with prior MI.
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 (%MDE periphery ). After a median follow-up of 2.4 years, 29 (20%) patients died. Patients with an above-median %MDE periphery were at higher risk for death compared with those with a below-median %MDE periphery (28% versus 13%, log-rank P <0.01). Multivariable analysis showed that left ventricular systolic volume index and %MDE periphery were the strongest predictors of all-cause mortality (adjusted hazard ratio HR for %MDE periphery , 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, %MDE periphery 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.
Yan et al. (2006) studied this question.