Abstract 13402: Outcomes of Cardiac Resynchronization Therapy in Ischemic versus Non-Ischemic Cardiomyopathy: A Patient-Level Meta-Analysis of 7 Randomized Clinical Trials

Abstract

Background: Data on whether CRT results in better clinical and echocardiographic outcomes in patients with NICM versus patients with ICM are conflicting. Objective: To determine if there are differences in clinical and echocardiographic outcomes of CRT in patients with ICM versus NICM. Methods: We analyzed patient-level data from 7 CRT trials (MIRACLE, MIRACLE-ICD, MIRACLE-ICD II, COMPANION, RAFT, MADIT-CRT, REVERSE) using Bayesian Hierarchical Weibull survival regression modeling, adjusted for baseline characteristics and presence of an ICD, to determine the effect of etiology of cardiac dysfunction on time to all-cause mortality alone and in combination with heart failure hospitalization (HFH). Kaplan-Meier (KM) survival curves were developed with unadjusted frequentist analyses. Linear regression was used to assess the effect of etiology of cardiomyopathy on echocardiographic measurements. Results: Of the 6252 patients included, 1535 (25%) were women, the median age was 66 (IQR 58-73), 3704 (59%) had ICM, and 3778 (60%) received CRT. Of those who received CRT, 2207 (58%) patients had ICM. Overall, CRT increased the time to HFH or death (hazard ratio (HR) 0.67, 95% credible interval (CrI) 0.56-0.82, p<0.001) with no difference by etiology (HR ratio 1.06, CrI 0.87-1.29, p=0.57). CRT increased the time to death (HR 0.71, CrI 0.55-0.93, p=0.019) with no difference by etiology (HR ratio 1.06, CrI 0.80-1.43, p=0.70), although overall event rate was higher in ICM. CRT in ICM increased the median survival and time free of HFH (70 versus 50 months, p=0.0015) and had borderline effect in NICM (p=0.05) (Figure). Echocardiographic data that were available for 2430 (39%) patients showed that CRT improvements in LVEF, LVEDD, and LVESD were larger for patients with NICM. Conclusion: CRT increased the time to HFH or death independent of etiology of cardiac dysfunction. However, CRT led to greater increases in LVEF and reductions in ventricular dimensions for patients with NICM.