Soluble ST2 and mixed venous oxygen saturation for prediction of mortality in patients with pulmonary hypertension

BACKGROUND: Although soluble suppression of tumorigenicity-2 (sST2) has been identified as a clinical biomarker for pulmonary hypertension (PH) by previous studies, the implication of sST2 combined with hemodynamic parameters in PH has not been well studied. This study aimed to evaluate the relationship between sST2 and hemodynamic parameters and to evaluate the predictive value of sST2 for mortality in patients with PH. METHODS: One hundred eighty-four incident patients with PH and 14 healthy controls were retrospectively enrolled by Shanghai Pulmonary Hospital for this retrospective study. After all patients underwent right heart catheterization, blood samples were collected and serum sST2 concentration was assessed by the Presage™ ST2 assay. Kaplan-Meier curve and Cox regression analyses were used to predict survival and the association between survival and different factors such as sST2, SvO(2). RESULTS: During a follow-up of 44.9 (IQR 28.5–64.4) months, 65 patients died. The median concentration of sST2 in PH patients was 33.1 ng/mL, which is higher than that in control group (23.1 ng/mL, P=0.005). Furthermore, for PH group, the level of sST2 was higher in non-survivors than that in survivors. Cox regression analyses demonstrated that sST2 and SvO(2) were independent risk factors for survival. In Kaplan-Meier curve analyses, elevated sST2 level and reduced SvO(2) predicted a poor outcome for patients with PH. CONCLUSIONS: Higher sST2 was independently associated with increased mortality, as well as lower SvO(2) in patients with PH. Especially, the combination of higher sST2 and lower SvO(2) had the strongest predictive value of mortality in patients with PH.