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)
Table 1: Current Classification for Pulmonary Hypertension [2]