| 1. Pulmonary Arterial Hypertension (PAH) |
| 1.1. Idiopathic (IPAH) |
| 1.2. Heritable/familial (FPAH) 1.2.1. BMPR2 |
| 1.2.2. ALK1, Endoglin |
| 1.2.3. Unknown |
| 1.3. Drug and toxin-induced |
| 1.4. Associated with (APAH) |
| 1.4.1.Conective tissue disorders |
| 1.4.2. HIV infection |
| 1.4.3. Portal hypertension |
| 1.4.4. Congenital heart diseases |
| 1.4.5. Schistosomiasis |
| 1.4.6. Chronic hemolytic anemia |
| 1.5. Persistent pulmonary hypertension of the newborn (PPHN) |
| 1’. Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) |
| 2. Pulmonary hypertension with left heart disease |
| 2.1. Systolic dysfunction |
| 2.2. Diastolic dysfunction |
| 2.3. Valvular disease |
| 3. Pulmonary hypertension due to lung diseases and/or hypoxia |
| 3.1. Chronic obstructive pulmonary disease (COPD) |
| 3.2. Interstitial lung disease |
| 3.3. Other pulmonary diseases with mixed restrictive and obstructive pattern |
| 3.4. Sleep disordered breathing |
| 3.5. Alveolar hyperventilation disorders |
| 3.6. Chronic exposure of high altitude |
| 3.7. Developmental abnormalities |
| 4. Chronic thromboembolic pulmonary hypertension (CTEPH) |
| 5. Pulmonary hypertension with indistinct, multi-factorial mechanisms |
| 5.1. Hematological disorders (e.g. myeloproliferative disorders, splenectomy, hemoglobinopathies) |
| 5.2. Systemic disorders (e.g. sarcoidosis, pulmonary Langerhans cell histocytosis, lymphangiomatosis) |
| 5.3. Metabolic disorders (e.g. glycogen storage disease, Gaucher’s disease, thyroid disorders) |
| 5.4. Others (e.g. tumoral obstruction, fibrosingmediastinitis, chronic renal failure and dialysis) |
