Pulmonary arterial hypertension (PAH) and pulmonary hypertension due to left heart diseases (PH-LHD) are distinct conditions but may share some features when a combined pre and post-capillary PH (CpcPH) is present. We analysed biomarkers of vasoconstriction (endothelin-1, ET1) and angiogenesis [angiopoietin (Ang) 1 and 2; Tie2 receptor] in PAH and LHD, and correlation with PH severity

Methods We included 55 patients undergoing a right heart catheterization for LHD or suspicion of PH. Blood samples were analysed for biomarkers

Results 37 patients had LHD (18 CpcPH) and 16 PAH. PH was more severe in PAH than in PH-LHD or CpcPH. No differences in ET1, Ang2 or Tie2 were observed between PH-LHD and PAH. Ang1 was higher in PAH than PH-LHD (fig1) or CpcPH (p=0.025). In PAH, Ang1 correlated with pulmonary vascular resistance, PVR and pulmonary artery compliance, CPA. In LHD, PVR and CPA correlated with Ang2 and ET1 (fig2)

Conclusion In PAH, Ang1 is higher than in PH-LHD and correlates with PVR and CPA. In LHD, its antagonist Ang2 correlates with PVR and CPA, suggesting that angiogenesis may be differently activated in these conditions