566 Myocardial left ventricular mechanical uniformity and adverse cardiac events following myocardial infarction

Abstract Background Despite limitations as a standalone parameter, left ventricular ejection fraction (LVEF) is the preferred measure of myocardial function and marker for post-infarction risk stratification. LV myocardial uniformity may provide superior prognostic information after acute myocardial infarction (AMI), which was subject of this study. Methods and Results: Consecutive patients with AMI (n = 1082; median age 63 years; 75% male) undergoing cardiac magnetic resonance (CMR) in median 3 days after infarction were included in this multicenter, observational study. Circumferential and radial uniformity ratio estimates (CURE and RURE) were derived from CMR feature-tracking as markers of mechanical uniformity (values between 0 and 1 with 1 reflecting perfect uniformity). The clinical endpoint was the 12-month rate of major adverse cardiac events (MACE), consisting of all-cause death, re-infarction, and new congestive heart failure. Patients with MACE (n = 73) had significantly impaired CURE [0.76 (IQR 0.67-0.86) versus 0.84 (IQR 0.76-0.89); p < 0.001] and RURE [0.69 (IQR 0.60-0.79) versus 0.76 (IQR 0.67-0.83); p < 0.001] compared to patients without events. While uniformity estimates did not provide independent prognostic information in the overall cohort, CURE below the median of 0.84 emerged as an independent predictor of outcome in post-infarction patients with LVEF >35% (n = 959) even after adjustment for established prognostic markers (hazard ratio 1.99; 95% confidence interval 1.06-3.74; p = 0.033 in stepwise multivariable Cox regression analysis). In contrast, LVEF was not associated with adverse events in this subgroup of AMI patients. Conclusions CMR-derived estimates of mechanical uniformity are novel markers for risk assessment after AMI and CURE provides independent prognostic information in patients with preserved or only moderately reduced LVEF.