Background/Purpose: Studies have shown that myocardial involvement may occur in systemic sclerosis (SSc) and lead to cardiac failure. We showed previously that cardiac magnetic resonance imaging (CMRI) with T1 mapping sequences could detect myocardial microscopic fibrosis in 50% of SSc patients, especially in those with diffuse cutaneous forms. However, no prospective data is yet available to analyze the prognostic impact of MMF on cardiac outcome in SSc patients.

Methods:   We conducted a single-center prospective study of consecutive patients with SSc fulfilling the ACR/EULAR criteria. CMRI with T1 mapping and multi-b value diffusion-weighted sequences were performed in all patients. T1 mapping sequences assess collagen myocardial infiltration, defining microscopic fibrosis. Myocardial microscopic fibrosis was defined on T1 mapping sequences by a value greater than 1250 ms, Patients were prospectively followed-up for the occurrence of cardiovascular (CV) events and decline in left ventricular ejection fraction (LVEF) assessed by cardiac ultrasonography.

Results:  Forty patients, 35 women and 5 men, mean age 54.7 ± 14.6 years, were included. At inclusion, patients had diffuse cutaneous forms in 19 cases, limited cutaneous forms in 16 cases, and SSc sine scleroderma in 5 cases. Median time from disease diagnosis to CMRI was 77 months (1-302). Myocardial microscopic fibrosis was found in 21 (53%) SSc patients.

After a median follow-up of 38.2 months (IQR 19.4-41.0), 10 (25%) patients experienced CV events: hospitalization for heart rhythm disorder in 7 cases, for heart failure in 2 cases (leading to death in one case) and unstable angina in one case.

Presence of myocardial microscopic fibrosis on CMRI at inclusion was significantly associated with a poorer CV event-free survival (P=0.02). Hazard ratio (95% confidence interval) for incident CV events in patients with myocardial microscopic fibrosis compared to those without was 4.47 (1.27-15.8) (Fig. A). 

In contrast, no difference in the decline of LVEF over time was noted between patients with and without myocardial microscopic fibrosis (from 62.0±3.2 and 62.9±4.7% at inclusion to 59.0±10.8 and 59.4±5.3% at 36 months, respectively) (Fig. B). 

Conclusion:  This study shows a significant association between myocardial microscopic fibrosis assessed by T1 mapping sequences on cardiac MRI and cardiovascular events in systemic sclerosis, but no impact on LVEF decline over time. The prognostic impact of myocardial microscopic fibrosis should be evaluated in larger studies, especially in patients with diffuse cutaneous forms.