Age-related progression of myocardial dysfunction in patients with Duchenne muscular dystrophy assessed by cardiac magnetic resonance tissue tracking: a case-control study.

Abstract

Background: Cardiovascular complications are the primary cause of mortality in patients with Duchenne muscular dystrophy (DMD). However, the dynamic progression underlying myocardial damage in DMD has not yet been fully elucidated. This study aimed to quantitatively assess myocardial dysfunction in patients with DMD across different age groups via cardiac magnetic resonance (CMR) tissue tracking technology.

Methods: Between August 2018 and January 2020, 110 patients with DMD diagnosed at the Pediatric Neurology Outpatient Department of West China Second University Hospital were consecutively and prospectively included in the study. The patients were categorized into three age groups: 3-6, 7-10, and 11-14 years. Based on left ventricular ejection fraction (LVEF), the patients were further divided into a normal LVEF group (LVEF ≥55%) and a decreased LVEF group (LVEF <55%). Furthermore, based on the presence of delayed enhancement, patients were classified into late gadolinium enhancement (LGE)-positive and LGE-negative groups. Additionally, 69 healthy controls were recruited for comparison. Left ventricular functional parameters and CMR tissue tracking-related parameters, such as global and regional myocardial strain of the left ventricle, were assessed. These included radial, circumferential, and longitudinal peak strains at the base, middle, and apex of the left ventricle. Statistical analyses were conducted via the t-test.

Results: A total of 99 patients and 61 healthy controls were included in the study. In comparison to the control group (n=21), patients aged 3-6 years in the DMD group (n=15) did not exhibit any decline. Patients aged 7-10 years in the DMD group (n=63), as compared with the control group (n=18), had lower LVEF (59.58%±7.09% vs. 63.39%±5.27%, P=0.044) and left ventricular global radial (37.34%±9.78% vs. 42.95%±9.22%, P=0.03), circumferential (-20.75%±3.77% vs. -22.09%±2.46%, P=0.03), and longitudinal (-13.91%±2.81% vs. -15.69%±2.52%, P=0.04) strain. Patients aged 11-14 years in the DMD group (n=21), as compared with the control group (n=22), demonstrated an even greater reduction in strain in the left ventricle for all parameters, except for LVEF. For patients in the normal LVEF group (n=77) or LGE-negative group (n=51), despite there being no significant difference in cardiac function compared with the control group, the global and regional myocardial strain of left ventricle was decreased.

Conclusions: Myocardial dysfunction predominantly manifests in DMD among children older than 7 years, exhibiting a subtle progression that exacerbates with advancing age. The myocardial injury tends to develop from the basal epicardium toward the apical and endocardial regions.