Assessment of Serum suPAR Levels in Patients with Group 1 and Group 4 Pulmonary Hypertension

Background/Objectives: Pulmonary hypertension (PH) is a progressive disorder with high morbidity and mortality, partly driven by chronic inflammation. Soluble urokinase plasminogen activator receptor (suPAR) reflects immune activation. We evaluated whether suPAR is altered in Group 1 and Group 4 PH and its association with clinical, echocardiographic, and laboratory parameters. Methods: We enrolled 44 PH patients (36 in Group 1, 8 in Group 4) and 45 healthy controls. All underwent clinical and echocardiographic assessments; right heart catheterization was performed in the PH patients. Serum suPAR was measured by ELISA. N-terminal pro B-type natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) were also assessed. Results: The suPAR plasma levels in the PH group were between 23.91 and 960.8 pg/mL (median: 73.14 p25: 62.77, p75: 167.13). suPAR was significantly higher in PH versus controls (73.14 [62.77-167.13] vs. 65.52 [53.06-80.91] pg/mL; p = 0.012). In logistic regression, systolic blood pressure, erythrocyte sedimentation rate, NT-proBNP, and suPAR independently predicted PH. suPAR correlated negatively with six-minute walk distance (r = -0.310) and tricuspid annular plane systolic excursion (r = -0.295) but positively with systolic pulmonary artery pressure (r = 0.241). On multivariate analysis, six-minute walk distance was the only independent correlate of suPAR (p = 0.004). suPAR levels did not differ between Group 1 and Group 4 PH. Conclusions: suPAR is elevated in Group 1 and Group 4 PH and correlates with functional and echocardiographic indices of disease severity. Larger prospective studies are needed to determine suPAR's role in diagnosis, risk stratification, and therapeutic decision-making.