Assessment of Myocardial Fibrosis in Marfan Syndrome Using Cardiac Magnetic Resonance Imaging

Impaired myocardial function and arrhythmia are important manifestations of Marfan syndrome (MFS). Studies assessing myocardial fibrosis in relation to these manifestations are scarce.

This cross-sectional, single-center study assessed ventricular volumes, ventricular function, and myocardial fibrosis by cardiac magnetic resonance imaging (CMR) in patients with MFS harboring a (likely) pathogenic FBN1 variant. The presence and extent of fibrosis were assessed by late gadolinium enhancement (LGE) and extracellular volume measurement (ECV). Data on 24-h Holter monitoring and clinical data were extracted from electronic patient records.

The study included 32 unselected patients with MFS (median age 38 years [range 10-69], 41% women). No focal myocardial fibrosis was detected. Six patients (21%) had diffuse fibrosis (ECV > 29%). No association was found between the presence of diffuse fibrosis and clinically relevant myocardial dysfunction. Five patients (16%) had reduced left ventricular ejection fraction (LVEF < 55%). While all of these exhibited mitral annular disjunction (MAD), only two had ECV > 29%. Patients with MAD had increased indexed LV volumes (median end-diastolic volume, 92 mL/m² [IQR, 78-100] vs. 78 mL/m² [IQR, 71-87]; median end-systolic volume, 31 mL/m² [IQR, 23-46] vs. 22 mL/m² [IQR, 21-28]), also after adjusting for the presence of mitral and aortic valve regurgitation. No differences in ECV were seen between patients with and without MAD.

In this cohort of patients with MFS, focal myocardial fibrosis was not detected using CMR. Although diffuse fibrosis was observed in 21% of patients, no evident connection to clinically relevant myocardial dysfunction was found. Further studies should evaluate the impact of diffuse fibrosis on clinical outcome prediction.