Introduction:
Cardiomyopathy is the leading cause of death in Duchenne Muscular Dystrophy (DMD), but traditional heart failure biomarkers have limited utility. Cardiac Troponin I (cTnI) has been used in DMD research studies as a marker of toxicity, but little is known about cTnI levels in asymptomatic patients. The goal of this study was to longitudinally evaluate cTnI, NTproBNP, and BNP in an asymptomatic DMD cohort. We hypothesized the biomarkers would not correlate with cardiac function, but some asymptomatic patients would exhibit a cTnI leak, reflecting ongoing myocardial inflammation related to disease progression.
Methods:
Asymptomatic DMD patients (N=69) and controls with normal cardiac evaluations (N=18) were enrolled. In DMD subjects, biomarker levels were obtained at time of cardiac magnetic resonance imaging (CMR), which included assessment of atrial and ventricular volumes, function, and late gadolinium enhancement (LGE). Normal ranges for biomarkers were created based on control values. Spearman correlation was used for analysis.
Results:
There was no consistent correlation between biomarkers and disease progression by CMR (Table 1). Several DMD subjects had transiently elevated cTnI (Fig 1). Those with elevated cTnI trended towards being more likely to have LGE on baseline CMR, though this did not reach statistical significance (p= 0.08).
Conclusions:
CTnI, BNP, and NTproBNP do not correlate with CMR assessment of cardiomyopathy progression. There is a subset of the DMD cohort with asymptomatic cTnI leak. While this cTnI leak is of uncertain clinical significance, it is important to recognize if cTnI is used to assess for cardiac toxicity in future drug trials.
Patterns of late gadolinium enhancement in Duchenne muscular dystrophy carriers
