Abstract 10069: Effect of Renin-Angiotensin-Aldosterone System Inhibitors on Left Ventricular Structure and Function in Duchenne Muscular Dystrophy Carriers

Introduction: Duchenne muscular dystrophy (DMD) is a rare X-linked neuromuscular disorder affecting 1:5,000 males that results in terminal injury to the skeletal muscle and the heart. Recent evidence suggests that DMD female carriers are also at increased risk of developing cardiomyopathy. Renin-angiotensin-aldosterone system (RAAS) antagonists reduce morbidity and mortality and inhibit adverse left ventricular remodeling in patients with heart failure with reduced ejection fraction. The benefit of RAAS inhibition in DMD carriers has not been studied to date. Hypothesis: We hypothesize that RAAS inhibition will improve left ventricular function and induce favorable left ventricular structural changes in DMD carriers over time. Methods: A retrospective, single-center cohort study was undertaken to compare cardiac magnetic resonance imaging (cMRI) parameters in DMD carriers at the time of RAAS inhibitor initiation and after treatment with RAAS inhibitors for at least 12 months. RAAS inhibitors included angiotensin converting enzyme inhibitors, angiotensin receptor blockers, or angiotensin receptor neprilysin inhibitors. Through EMR review, demographic data and cMRI parameters were collected retrospectively on 20 consecutive DMD carriers. Results: The average time elapsed between cMRIs was 39 months. Overall, left ventricular ejection fraction (LVEF) increased in DMD carriers over time, though the improvement in LVEF did not reach significance (57% + 8 vs 59% + 6, p=0.2). However, subgroup analysis of 16 DMD carriers with reduced LVEF (defined as LVEF + 6 vs 58% + 7; p= 0.004). DMD carriers with reduced LVEF additionally demonstrated a significant decrease in left ventricular end systolic volume index (LVESVi) after RAAS inhibition (38 + 10 vs 32 + 10 ml/m2; p= 0.013). Conclusions: DMD carriers with reduced LVEF showed significant improvement in LVEF and LVESVi following RAAS inhibition. Collectively, the data suggest that RAAS inhibition significantly improves left ventricular systolic function and significantly reduces maladaptive left ventricular remodeling and dilation in this population.