Diagnostic Cut-off Values for Newly Developed Noninvasive Elastance-Based Indices in Duchenne Muscular Dystrophy-Associated Cardiomyopathy.

Duchenne muscular dystrophy–associated cardiomyopathy (DMDAC) is a leading cause of mortality in patients with Duchenne muscular dystrophy. Conventional reliance on ejection fraction (EF) may underestimate early myocardial dysfunction. This study utilized the previously published dataset by Ajiboye et al. (Heart Vessels 40(8):696–706, 2025) comprising 30 DMDAC patients who underwent serial cardiac magnetic resonance (CMR) imaging between 2014 and 2023. Noninvasive indices—mean elastance, contractility, and energy efficiency—were derived using an innovative optimization approach by integrating patients specific brachial blood pressure and CMR-based left-ventricular volume changes. Diagnostic performance of the proposed indices relative to EF < 55% was obtained using receiver operating characteristic (ROC) curve to determing the cut-off values. All three indices, derived noninvasively, demonstrated statistically significant delineation for 55% EF, with AUC of 0.92 for mean elastance, 0.96 for contractility, and 1.00 for energy efficiency. Optimal cut-offs were 0.50 mmHg/mL, 1.72 mmHg/mL, and 69.8%, respectively. These findings support newly developed mean elastance, contractility, and energy efficiency as viable noninvasive diagnostic indices for DMDAC. Incorporating these indices alongside EF could improve early detection and risk stratification in clinical decision making.