Objective: The objective of this study was to evaluate the incidence of pulmonary hypertension (PH) and determining factors in patients with systemic sclerosis (SSc) and a DLCO < 60% predicted.Methods:In this bicentric, prospective cohort study, patients with SSc were assessed at baseline and after 3 years clinically including right heart catheterization (RHC). Analysis of determining factors for development of PH was performed using univariate and multivariate analysis.Results:Ninety-six patients with mean pulmonary artery pressure (mPAP) <25 mmHg at baseline were followed 2.95±0.7 (median 3) years. Seventy-one had a second RHC; 18 of the 71 patients (25.3%) developed PH, 5 (7%) a SSc-associated pulmonary arterial hypertension. For patients with mPAP between 21 and 24 mmHg at baseline, the likelihood of presenting with PH as opposed to normal pressures on follow-up was significantly higher (p=0.026). Pulmonary vascular resistance, tricuspid regurgitation velocity, diffusion capacity and size of inferior vena cava at baseline were independent predictors for development of PH during follow-up.Conclusion:In a selected cohort of SSc patients with a DLCO < 60%, pulmonary pressures appear to rise progressively during follow up. In this population using prospective RHC during follow-up it was possible to identify manifest PH in almost 25% of 44 patients. Therefore, regular clinical assessment including RHC might be useful in SSc-patients.Most important findings:In a selected cohort of SSc patients pulmonary pressures appear to rise progressively, leading to a development of manifest PH in 25% within 3 years
