Abstract 12450: Myocardial Fibrosis Burden Predicts Left Ventricular Ejection Fraction and is Modified by Age and Steroid Treatment Duration in Duchenne Muscular Dystrophy
Background: Patients with Duchenne muscular dystrophy (DMD) typically exhibit progressive cardiac and skeletal muscle dysfunction, and are commonly treated with corticosteroids to prolong ambulation. Myocardial fibrosis and steroid treatment may modulate the progression of cardiac dysfunction in DMD patients. We aimed to longitudinally characterize the impact of myocardial fibrosis and steroid treatment on the progression of cardiac dysfunction using cardiac magnetic resonance (CMR) in a large DMD cohort.
Methods: Serial CMR studies performed on DMD patients were reviewed for LVEF and late gadolinium enhancement (LGE) status, a marker for myocardial fibrosis. LVEF was modeled by examining effects of patient age, steroid treatment duration, LGE status, and myocardial fibrosis burden, as assessed by the number of LGE positive (LGE+) LV segments.
Results: We analyzed 469 CMR studies from 99 DMD patients with ≥4 CMRs. Patient age at time of CMR ranged from 6.6 to 29.4 (median 12.3) years. There were 146 (31.1%) LGE+ studies and 59 studies (12.6%) that demonstrated depressed LVEF (LVEF<55%). An age-only model demonstrated that LVEF declined 0.58±0.10%/yr (p<0.0001, r2=0.067). Univariate modeling showed significant associations between LVEF and steroid treatment duration, presence of LGE, and number of LGE+ LV segments; multivariate modeling showed that LVEF declined by 0.93±0.09% for each LGE+ LV segment (p<0.0001, r2=0.171), while age and steroid treatment duration were no longer significant. The number of LGE+ LV segments increased with age by 1.2 segments/year (95% confidence interval 1.1-1.2), and steroid treatment partially mitigated this increase (interaction term β=-0.01±0.005, p=0.010).
Conclusions: Progressive myocardial fibrosis, as imaged by LGE on CMR, is a strong marker for the decline in LVEF in DMD patients. Steroid treatment partially attenuates the age-related increase in myocardial fibrosis burden.
Author Disclosures: A. Tandon: Ownership Interest; Modest; GE, Medtronic. C.R. Villa: None. K.N. Hor: None. J.L. Jefferies: None. Z. Gao: None. J.A. Towbin: None. B.L. Wong: None. W. Mazur: None. R.J. Fleck: None. J.J. Sticka: None. D.W. Benson: None. M.D. Taylor: None.
- © 2014 by American Heart Association, Inc.