Soluble ST2 protein as a new biomarker in patientswith precapillary pulmonary hypertension

IntroductionNon-invasive tests that may improve clinical evaluation of pulmonary hypertension (PH) are needed. The purpose of this study was to assess the role of soluble ST2 (sST2) in patients with PH.Material and methodsA total of 57 patients with chronic thromboembolic PH and 43 patients with idiopathic arterial PH were enrolled in this study. All patients were evaluated for World Health Organization (WHO) functional class (FC), N-terminal prohormone B-type natriuretic peptide (NT-proBNP), troponin T (TnT), and hemodynamics. Plasma sST2 was assessed by an immu­nofluorescent in vitro diagnostic assay. All patients were followed up from the date of blood sampling. The endpoint was all-cause death.ResultsThe median sST2 concentration was 32.8 ng/ml (IQR: 21.6–48.5 ng/ml) in the whole study population. Significant differences were found between median sST2 in successive WHO FCs (FC II vs. FC III, p = 0.002; FC III vs. FC IV, p = 0.12; FC II vs. FC IV, p = 0.008). Significant correlations were found between sST2 and hemodynamic parameters: mean right atrial pressure (r = 0.56; p < 0.05), mean pulmonary artery pressure (r = 0.25; p < 0.05), cardiac index (r = –0.40; p < 0.05), pulmonary vascular resistance (r = 0.41; p < 0.05), and between sST2 and WHO FC (r = 0.36; p < 0.05), NT-proBNP (r = 0.55; p < 0.05), and TnT (r = 0.44; p < 0.05). sST2 concentration above the median was associated with worse clinical prognosis (p = 0.02, Kaplan-Meier).ConclusionssST2 seems to be a marker of poor clinical prognosis in patients with PH.