Abstract 12248: Decreased Left Ventricular Hemodynamic Forces As A Novel Biomarker Of Myocardial Dysfunction In Duchenne Muscular Dystrophy

Abstract

Introduction: Patients with Duchenne muscular dystrophy (DMD) develop progressive cardiomyopathy. Cardiac magnetic resonance (CMR) imaging is used to identify global and regional function, as well as myocardial fibrosis in DMD. Unique left ventricular (LV) biomechanics cannot be assessed through conventional CMR techniques. Thus, we investigated hemodynamic force (HDF) through cine derived wall motion in the LV as a novel biomarker of myocardial dysfunction in DMD patients. Methods: This retrospective study consisted of CMR studies from DMD patients and age-matched controls. Feature-tracking (Qstrain, Medis) was performed on short-axis and long-axis cine imaging to capture LV wall motion. A novel technique based on diffeomorphic mapping was used to calculate three-dimensional LV kinematic models and HDF vectors throughout the cardiac cycle (Figure 1A). The apical-basal, lateral-septal, and anterior-posterior HDF vectors were correlated with global and regional functional parameters. Results: Eleven DMD and 11 controls were enrolled with LV EF 51 ± 6 vs 56 ± 6 (p = 0.09). DMD patients had decreased apical-basal and lateral-septal HDF across multiple points in the cardiac cycle compared to controls (Figure 1B). Six DMD patients with LV EF < 55% were compared to 5 DMD patients with normal EF, demonstrating significant decrease in apical-basal systolic root mean square (RMS) HDF (p = 0.015), lateral-septal systolic RMS HDF (p = 0.009), anterior-posterior diastolic RMS HDF (p = 0.011), and magnitude systolic RMS HDF (p = 0.011) in patients with dysfunction. Absolute magnitude RMS HDF in all axes correlated with LV global longitudinal strain, LV global circumferential strain, and LV EF (r = 0.59 to 0.81, p < 0.05). Conclusions: Cine derived HDF may be a more sensitive measure of LV dysfunction in DMD patients. Apical-basal HDF has potential as a novel biomarker for progression of disease.