Infarct characterization and quantification by delayed enhancement cardiac magnetic resonance imaging is a powerful independent and incremental predictor of mortality in patients with advanced ischemic cardiomyopathy
BACKGROUND: Infarct heterogeneity has been shown to be independently associated with adverse outcomes in previous smaller studies. However, it is unknown whether infarct characterization is an independent predictor of all-cause mortality in patients with advanced ischemic cardiomyopathy, after adjusting for clinical risk factors, severity of ischemic mitral regurgitation, incomplete revascularization, and device therapy. METHODS AND RESULTS: A total of 362 patients with ischemic cardiomyopathy (left ventricular dysfunction with >70% stenosis in ≥1 epicardial coronary artery) underwent delayed hyperenhancement-magnetic resonance imaging and coronary angiography between 2002 and 2006. Total myocardial scar and peri-infarct (PI) area were measured using various threshold techniques. Multivariate survival analysis (primary end point of all-cause mortality) was conducted. One hundred fifty-seven deaths occurred during a mean 5.4-year follow-up (mean left ventricular ejection fraction, 23±9%; mean end-systolic volume index, 113±48 mL; mean total myocardial scar %, 25.5±16.0%; mean PI%, 5.7±2.9%). PI% (β=2.07; P<0.001) was an independent predictor of survival, independent of age, end-systolic volume, sex, mitral regurgitation, diabetes mellitus, dyslipidemia, coronary artery disease severity, implantable cardioverter defibrillator, and incomplete revascularization. PI% using 2 to 3 SD technique yielded the highest incremental prognostic power (χ(2) score 149). CONCLUSIONS: In advanced ischemic cardiomyopathy, PI% is a powerful independent and incremental predictor of all-cause mortality. Infarct heterogeneity offers substantial further risk stratification when compared with quantification of total myocardial scar % alone even after adjusting for clinical risk factors, end-systolic volume index, mitral regurgitation, incomplete revascularization, and implantable cardioverter defibrillator implantation.