Abstract 4145861: Systemic Sclerosis is Associated with Sub-Clinical Abnormalities in Myocardial Energetics, Perfusion and Increased Fibrosis

Background: Primary cardiac involvement in systemic sclerosis (SSc) is heterogenous, poorly defined and associated with significant cardiac morbidity and mortality. The underlying mechanism is not well understood but may include the impact of coronary microvascular dysfunction and myocardial inflammation. Myocardial cellular metabolic alterations in SSc are yet to be established. Aims: Using 31 Phosphorous magnetic resonance spectroscopy ( 31 P MRS) and cardiovascular magnetic resonance (CMR), we aimed to establish if myocardial energetics, measured as phosphocreatine (PCr) /ATP ratio, and quantitative myocardial perfusion were reduced in individuals with SSc compared to healthy volunteers (HV). Methods: A total of 35 age and sex matched participants were recruited (25 SSc, 10 HV). All subjects underwent 31 P MRS and comprehensive CMR protocol including volumetric analysis, quantitative myocardial perfusion and T1 mapping. Results: Table-1 shows clinical and CMR / 31 P MRS data. Bi-ventricular volumes, systolic function and left atrial function were similar in both groups. NT-Pro BNP and myocardial extra cellular volume (ECV) were significantly increased in SSc. Both PCr/ATP and myocardial perfusion reserve (MPR) were significantly reduced in SSc compared with controls. The disease activity as measured by the European Scleroderma Trials and Research group (EUSTAR) activity index did not correlate with either NTproBNP (P=0.79), PCr/ATP (P=0.35) or MPR (P=0.6). Conclusions: In addition to validating our previous observations of reduced perfusion and increased myocardial fibrosis in SSc, we have demonstrated for the first time significant reductions in myocardial energetics in patients with SSc. These findings provide further valuable insight into the pathogenesis of primary myocardial disease in SSc.