Outcomes of Heart Failure in Adult Patients with Muscular Dystrophy: A Single Center Experience

Abstract

Introduction Cardiomyopathies associated with Duchenne (DMD) or Becker (BMD) muscular dystrophy have been historically noted to have poor outcomes in the pediatric population, but studies in the adult population are sparse. Hypothesis: The goal of this study was to determine the rates of ejection fraction (EF) decline and overall survival outcomes in a cohort of adult patients with dystrophinopathic cardiomyopathies on contemporary heart failure therapies. Methods This is a retrospective cohort study of 41 adults with muscular dystrophy (29 with DMD, 7 with BMD, 5 with other types of muscular dystrophy) out of 1582 heart failure patients followed in the Loma Linda University International Heart Institute clinic who were evaluated using the following outcome measures: mortality and rate of EF decline comparing first and most recent echocardiogram. Results The cohort had a mean age of 32 years (DMD was 31 and BMD was 35 years), 71% with DMD, 17% with BMD, 100% male, 44% Caucasian, 37% Hispanic, and 12% African American. Mean follow up time in clinic was 6.79 years. Mortality within 5 years was 29% (17% in the DMD group and 33% in the BMD group). Mean EF on the most recent echocardiogram was 31.7% for the DMD group and 28.0% for the BMD group. Of the patients who are still alive (n=29), 83% are on a beta blocker and 93% are on an ACEi, ARB, or ARNI. Of those who have died (n=12), 92% were on a beta blocker and 75% were on ACEi, ARB, or ARNI. Twelve out of 31 survivors were on ivabradine versus 0 out of 12 who died (p=0.08). The mean rate of EF decline in the overall cohort was about 3.1% per year (3.0% per year for DMD, 4.4% year for BMD); see Figure 1. The mean rate of EF decline in those who died was 3.7% per year, and 2.8% in those who are still alive. Conclusions Dystrophinopathic cardiomyopathies are associated with progressive left ventricular remodeling and about 3% per year mean drop in EF. Survival tended to be greater in patients treated with ivabradine. Further research is needed in the adult muscular dystrophy population to evaluate the effectiveness of contemporary heart failure therapy including ivabradine in slowing the progression of their cardiomyopathy