Real World Barriers to Diagnostic Cardiac Imaging in Adults with Duchenne Muscular Dystrophy Cardiomyopathy

Aims: Cardiomyopathy is universally penetrant in young adults with Duchenne muscular dystrophy (DMD), and is increasingly the preponderant cause of death. We sought to determine the rates of, and reasons for, failed diagnostic cardiac imaging in our DMD multidisciplinary care centre as well as the level of agreement between imaging modalities, in order to guide the optimal strategy for cardiac imaging in these patients. Methods and results: We followed all patients attending a Comprehensive Multidisciplinary Adult DMD clinic over 4 years. All attendees underwent transthoracic echocardiography (TTE) and were offered referral for cardiac MRI (CMR). Age, cardiac medications, left ventricular ejection fraction (LVEF), ambulatory status, airway adjuncts and presence and degree of cardiac fibrosis were recorded. A total of 33 patients enrolled, median age 20, with mean follow-up of 3 years and 3 months. Mean LVEF was 51% at enrollment and 45% at follow-up. Presence of any degree of mitral regurgitation correlated strongly to left ventricular systolic dysfunction. CMR was completed in just 25% of patients, all of whom had extensive midwall fibrosis. Of those in whom CMR failed, 52% were unable to lie flat or position correctly for scanning, predominantly due to muscle contractures. Despite suboptimal TTE imaging in 75%, there was good agreement in LVEF between CMR and TTE. Conclusion: We found a high rate of failure to complete diagnostic cardiac imaging in this group of patients with impaired mobility. Our study highlights the importance of multimodality imaging, and practical strategies to overcome environmental obstacles to diagnostic imaging, to better guide aggressiveness of treatment for DMD and its inherent cardiomyopathy.