Abbreviations
ALK-1: Activin A receptor type II-like kinase-1; BMPR2: Bone morphogenetic protein receptor 2; CCB: Calcium channel blockers; CHD: Congenital heart diseases; Chest HRCT: Chest High resolution computed tomography; CI: Cardiac index; CMR: Cardiac magnetic resonance imaging; CO: Cardiac output; CTD: Connective tissue disease; CPET: Cardiopulmonary exercise testing; CTEPH: Chronic thrombo-embolic pulmonary hypertension; DLCO: Diffusing lung capacity of carbon monoxide; DLCO/VA: Diffusing lung capacity of carbon monoxide/alveolar volume; ESC: European Society of Cardiology; ERS: European Respiratory Society; HHC: Hereditary hemorrhagic telangiectasia; HIV: Human immunodeficiency virus; INR: International Normalized Ratio; NIH: National Institute of Health; NO: Nitric oxide; NYHA: New York Heart Association; PAH: Pulmonary arterial hypertension; PFT: Pulmonary function test; mPAP: Mean pulmonary arterial pressure; PCWP: Pulmonary capillary wedge pressure; PVOD: Pulmonary veno-occlusive disease; PVR: Pulmonary Vascular Resistance; RAP: Right atrial pressure; PaO2: Partial pressure of arterial oxygen; PaCO2: Partial pressure of arterial carbon dioxide; PDGF: Platelet-Derived Growth Factor; RCT: Randomized clinical trial; RHC: Right heart catheterization; SpO2: Pulse arterial oxygen saturation; SR: Sex ratio; SvO2: Mixed venous oxygen saturation; TTE: Transthoracic Doppler-echocardiography; TKI: tyrosine kinsase inhibitor; TLC: Total lung capacity; TPR: Total Pulmonary Resistance; TGF: beta Transforming growth factor beta; VEGF: Vascular endothelial growth factor; 6-MWD: 6-minute walk distance.