ABSTRACT: To improve outcome in pulmonary arterial hypertension, earlier diagnosis and better prognostic assessments are required. We aimed to investigate the diagnostic and prognostic potential of plasma proteins related to pathways recognized in pulmonary arterial hypertension including coagulation, inflammation, and metabolism. Forty-two proteins were analysed with proximity extension assay from plasma of 20 healthy controls and 150 patients, including (pulmonary arterial hypertension, n = 48, whereof 33 also during early treatment follow-ups); chronic thromboembolic pulmonary hypertension (CTEPH, n = 20); pulmonary hypertension (PH) due to heart failure (HF) with preserved ejection fraction (HFpEF-PH, n = 31); PH due to HF with reduced ejection fraction (HFrEF-PH, n = 36); and HF without PH (Dyspnoea/HF-non-PH, n = 15). Patients' haemodynamics were assessed by right heart catheterization. Plasma ADAMTS13 in incident pulmonary arterial hypertension was lower compared to the healthy controls (p = 0.055), as well as CTEPH (p < 0.0001), HFrEF-PH (p < 0.0001), HFrEF-PH (p < 0.0001), and Dyspnoea/HF-non-PH (p < 0.0001). Adjusted for age and sex, ADAMTS13 discriminated pulmonary arterial hypertension from the other disease groups with an AUC of 0.91 (sensitivity = 87.5%, and specificity = 78.4%). Higher plasma von Willebrand factor was associated with worse survival (log-rank p = 0.0029), and a higher mortality rate (adjusted hazard ratio 1.002, 95% confidence interval 1-1.004; p = 0.041). Adjusted for age, sex, and combined with the ESC/ERS risk score, von Willebrand factor predicted mortality (median follow-up 3.6 years) in pulmonary arterial hypertension with an AUC of 0.94 (sensitivity = 81.3%, and specificity=93.8%). ADAMTS13 may be a promising biomarker for early detection of PAH and von Willebrand factor as a candidate prognostic biomarker. The putative additional value of von Willebrand factor to the European multiparametric risk assessment strategy remains to be elucidated.
