| 1 Pulmonary arterial hypertension (PAH) |
| 1.1 Idiopathic PAH |
| 1.2 Heritable PAH |
| 1.3 Drug- and toxin-induced PAH |
| 1.4 PAH associated with: |
| 1.4.1 Connective tissue disease |
| 1.4.2 HIV infection |
| 1.4.3 Portal hypertension |
| 1.4.4 Congenital heart disease |
| 1.4.5 Schistosomiasis |
| 1.5 PAH long-term responders to calcium channel blockers |
| 1.6 PAH with overt features of venous/capillaries (PVOD/PCH) involvement |
| 1.7 Persistent PH of the newborn syndrome |
| 2 PH due to left heart disease |
| 2.1 PH due to heart failure with preserved LVEF |
| 2.2 PH due to heart failure with reduced LVEF |
| 2.3 Valvular heart disease |
| 2.4 Congenital/acquired cardiovascular conditions leading to post-capillary PH |
| 3 PH due to lung diseases and/or hypoxia |
| 3.1 Obstructive lung disease |
| 3.2 Restrictive lung disease |
| 3.3 Other lung disease with mixed restrictive/obstructive pattern |
| 3.4 Hypoxia without lung disease |
| 3.5 Developmental lung disorders |
| 4 PH due to pulmonary artery obstructions |
| 4.1 Chronic thromboembolic PH |
| 4.2 Other pulmonary artery obstructions |
| 5 PH with unclear and/or multifactorial mechanisms |
| 5.1 Hematological disorders |
| 5.2 Systemic and metabolic disorders |
| 5.3 Others |
| 5.4 Complex congenital heart disease |
