Predictors of subclinical systemic sclerosis primary heart involvement characterised by microvasculopathy and myocardial fibrosis

Objectives. SSc primary heart involvement (SSc-pHI) is a significant cause of mortality. We aimed to characterize and identify predictors of subclinical SSc-pHI using cardiovascular MRI. Methods. A total of 83 SSc patients with no history of cardiovascular disease or pulmonary arterial hypertension and 44 healthy controls (HCs) underwent 3Tesla contrast-enhanced cardiovascular MRI, including T1 mapping and quantitative stress perfusion. High-sensitivity troponin I and N-terminal pro-brain natriuretic peptide were also measured. Results. Cardiovascular MRI revealed a lower myocardial perfusion reserve in the SSc patients compared with HCs {median (interquartile range (IQR)] 1.9 (1.6-2.4) vs 3 (2-3.6), P < 0.0011. Late gadolinium enhancement, indicating focal fibrosis, was observed in 17/83 patients but in none of the HCs, with significantly higher extracellular volume (ECV), suggestive of diffuse fibrosis, in SSc vs HC [mean (s.D.) 31 (4) vs 25 (2), P < 0.001]. Presence of late gadolinium enhancement and higher ECV was associated with skin score [odds ratio (OR)=1.115, P=0.048; R-2 =0.353, P=0.004], and ECV and myocardial perfusion reserve was associated with the presence of digital ulcers at multivariate analysis (R-2 =0.353, P <0.001; R-2 =0.238, P =0.011). High-sensitivity troponin I was significantly higher in patients with late gadolinium enhancement, and N-terminal pro-brain natriuretic peptide was associated with ECV (P < 0.05). Conclusion. Subclinical SSc-pHI is characterized by myocardial microvasculopathy, diffuse and focal myocardial fibrosis but preserved myocardial contractile function. This subclinical phenotype of SSc-pHI was associated with high-sensitivity troponin I, N-terminal pro-brain natriuretic peptide, SSc disease severity and complicated peripheral vasculopathy. These data provide information regarding the underlying pathophysiological processes and provide a basis for identifying individuals at risk of SSc-pHI.

Automated summary

The subclinical phenotype of SSc primary heart involvement is characterized by myocardial microvasculopathy, diffuse and focal myocardial fibrosis while retaining preserved myocardial contractile function. This phenotype is associated with high-sensitivity troponin I, N-terminal pro-brain natriuretic peptide, SSc disease severity, and complicated peripheral vasculopathy, providing insights into potential underlying pathophysiological processes and risk factors for SSc-pHI.