BACKGROUND AND AIMS: The role of biomarkers in diagnosing pulmonary hypertension (PH) and distinguishing between pre- and post-capillary PH remains poorly understood. We aimed to identify biomarkers with a strong association with mean pulmonary arterial pressure, mPAP (PH diagnosis) and pulmonary vascular resistance, PVR (pre-capillary component), but not with pulmonary arterial wedge pressure, PAWP (post-capillary component). METHODS: Blood samples were collected in patients undergoing right heart catheterization within a prospective cross-sectional study. Biomarkers measured included BMP10, NT-proBNP, ANG2, ESM1/endocan, FGF23, GDF15, IGFBP7, IL6, MyBPC3, proC3, and proC6/endotrophin. Primary outcomes were mPAP, PVR, and PAWP, while secondary outcomes included PH diagnosis (mPAP >
20 mmHg) and elevated PVR (>
2 Wood units). Multivariable linear and logistic regression models were used to assess the relationship between biomarkers and outcomes. RESULTS: Of the 127 patients included (age 66 ± 13 years, 54% female), 73% were diagnosed with PH. BMP10, NT-proBNP, ANG2, MyBPC3, and FGF23 showed a strong association with mPAP (p <
0.001). BMP10 and NT-proBNP were strongly associated with PVR (p <
0.001), while NT-proBNP and ANG2 were strongly associated with PAWP (p <
0.001). NT-proBNP had the strongest association with the diagnosis of PH (area under the curve = 0.76). BMP10 was the only biomarker associated with elevated PVR (OR 1.60, 95%CI 1.01-2.54, p = 0.04) but not with PAWP (p = 0.86). CONCLUSIONS: Several biomarkers were strongly associated with mPAP, PAWP, and PVR. BMP10 was the only biomarker strongly associated with mPAP and PVR, but not with PAWP, thus reflecting the pre-capillary PH component. Measurement of BMP10 along with NT-proBNP may aid in diagnosing PH.