Abstract 19087: Cardiac Magnetic Resonance Imaging Increased Utilization of Cardiac Treatment in Young Duchenne Muscular Dystrophy Patients

Introduction: Duchenne muscular dystrophy (DMD), an X-linked recessive disorder affecting up to 1 in 6000. DMD-associated cardiomyopathy (DMD-C) is universal and starts as young as 6 years of age by cardiac magnetic resonance imaging (CMR) with presence of late gadolinium enhancement (LGE). Heart failure signs and symptoms are vague due to skeletal muscle myopathy. Echocardiogram only detects global dysfunction by left ventricular ejection fraction (LVEF) which rarely occur before 10 years of age. The current DMD cardiac care consideration guidelines (CCCG) recommends initiation of cardiac medication around 10 years of age or if there is LGE and/or LVEF abnormalities .

Hypothesis: We hypothesized young DMD were more likely to have cardiac therapy initiated after CMR compared to only TTE evaluation.

Methods: Electronic medical records for DMD patients (6 to < 10 years) who underwent routine TTE or CMR evaluation between 2014-2023 were included. Demographic data at the time of the study and initiation of cardiac medication including angiotensin-converting-enzyme inhibitor (ACE-I), Angiotensin II receptor blockers (ARB) and/or Mineralocorticoid Receptor Antagonists (MRA) were recorded.

Results: 150 patients met inclusion criteria, of these 81 patients underwent TTE only and 69 underwent CMR evaluation in lieu of TTE with no difference in age (8.4±1.1 versus 8.6±0.8 years, P = 0.07). Of those with TTE evaluation 10/81 (12.3%) was initiated with ACE-I or ARB ( 3/10 (33%) had LVEF < 55% (average 53.5%), 4/10 (40%) turned 10 on the follow-up visit and 3/10 (30%)) because family requested. Of the 69 patients with CMR, 51/69 (73.9%) had cardiac therapy initiated (28/51 (54.9%) because of new LGE, 6/51 (11.8%) due to isolated LVEF < 55% (average 53%), 12/51 (23.5%) would turn 10 on follow-up and 5/51 (9.8%)) the family requested. All patients with LGE on CMR also had MRA therapy started.

Conclusions: DMC-C is universal and the use of CMR improved disease specific treatment of both ACE-I/ARB and MRA. Duboc et al, in a placebo control study showed that in 9.5 - 13.5 year old DMD patients treated with ACE-I had fewer patients develop dysfunction with reduced mortality at 10 years. Early and aggressive treatment may attenuate DMD-C. Future longitudinal study is needed.