Abstract 12052: Myocardial Extracellular Matrix Expansion Detected With Cardiac MRI: A Biomarker of Cardiomyopathic Disease in Duchenne Muscular Dystrophy
Introduction: Duchenne muscular dystrophy (DMD) cardiomyopathy is a progressive disease for which standard heart failure therapies have limited efficacy. Disease-specific therapies are needed that can be initiated before irreversible myocardial damage ensues. In order to evaluate therapeutic efficacy, surrogate endpoints other than ejection fraction must be found.
Hypothesis: The study hypothesis is that T1 and extracellular volume fraction (ECV) mapping using cardiac magnetic resonance imaging (CMR) can detect diffuse extracellular matrix expansion in DMD patients with normal left ventricular ejection fraction (LVEF) and without late gadolinium enhancement (LGE).
Methods: 28 DMD and 11 healthy control participants were prospectively enrolled. CMR using a modified Look-Locker (MOLLI) sequence was performed before and after contrast administration. T1 and ECV maps of the mid left ventricular myocardium were generated and regions of interest were contoured using the standard 6-segment AHA model. Global and segmental values were compared between DMD and controls using a Wilcoxon rank-sum test.
Results: DMD participants had significantly higher mean native T1 compared with controls (1045ms vs 988ms, p<0.001) (Fig 1A). DMD participants with normal LVEF and without evidence of LGE also demonstrated elevated mean native T1 (1036ms vs 988ms, p<0.001, and 1039ms vs 988ms, p=0.001) (Fig 1C, 1E). Mean post-contrast T1 values were not significantly different between DMD participants and controls. DMD participants had a significantly greater mean ECV than controls (0.31 vs 0.24, p<0.001), even in the settings of normal LVEF (0.29 vs 0.24, p<0.001) and negative LGE (0.30 vs 0.24, p<0.001) (Fig 1B, 1D, 1F).
Conclusions: DMD participants have elevated native T1 and ECV in left ventricular myocardium, even in the setting of normal LVEF and in the absence of LGE. T1 and ECV mapping in DMD have potential to serve as surrogate cardiomyopathy outcome measures for clinical trials.
- Duchenne muscular dystrophy
- Cardiac Magnetic Resonance Imaging
- Extracellular Volume Fraction
- T1 Mapping
Author Disclosures: J.H. Soslow: None. S.M. Damon: None. K. Crum: None. M. Lawson: None. J.C. Slaughter: None. M. Xu: None. A.E. Arai: None. D.B. Sawyer: None. D.A. Parra: None. B.M. Damon: None. L.W. Markham: None.
- © 2015 by American Heart Association, Inc.