Quantification of myocardial extracellular volume fraction by cardiac magnetic resonance for early detection of the left ventricle involvement in systemic sclerosis

Cardiologia CROATICA Background: Early identification of myocardial dysfunction is challenging for many cardiovascular diseases and systemic sclerosis (SSc) is an unique model of progressive myocardial fibrosis. Cardiac magnetic resonance with late gadolinium enhancement (LGE) can detect fibrosis in advanced stages of SSc, but is limited in the early stage due to the diffuse nature of fibrotic changes. T1 mapping is able to quantify myocardial fibrosis and can be used to quantify myocardial extracellular volume fraction (EVF), which changes when collagen content increases. We aimed to determine whether EVF quantification could detect subclinical left ventricular (LV) abnormalities and to investigate the relationship between EVF and subtle diastolic and systolic dysfunction. Materials and Methods: T1 mapping and EVF quantification were prospectively performed in 33 consecutive SSc patients with normal echocardiography, no severe diastolic dysfunction, no pulmonary hypertension at rest and no LGE, as well as in 16 healthy controls. The study was approved by the local ethics committee and all subjects gave written informed consent. Results: SSc patients had significantly higher global EVF (P<0.0001) and higher local EVF for all basal and mid-ventricular LV segments (P<0.01). Global EVF significantly correlated with left atrial volume (P<0.0001) and with the grade of diastolic dysfunction (P=0.016). Majority of SSc patients (63%) had both a high global EVF and low global systolic circumferential strain. Conclusions: EVF quantification can identify LV abnormalities at an early stage in SSc patients. These abnormalities may reflect increase in diffuse myocardial fibrosis and are associated with subtle diastolic and systolic LV dysfunction.