Table 1.

Clinical classification of pulmonary hypertension.

Group 1: Pulmonary Arterial Hypertension (PAH)
1.1 Idiopathic
1.2 Heritable (BMPR2, ALK1, endoglin, unknown)
1.3 Drugs and toxins induced
1.4 Associated with (APAH): connective tissue diseases, HIV infection, Portal Hypertension, Congenital heart disease, Schistosomiasis, Chronic haemolytic anemia
1.5 Persistent pulmonary hypertension of the newborn
Group 1’: Pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis
Group 2: Pulmonary hypertension due to left heart disease
2.1 Systolic dysfunction
2.2 Diastolic dysfunction
2.3 Valvular disease
Group 3: Pulmonary hypertension due to lung diseases and/or hypoxaemia
3.1 Chronic obstructive pulmonary disease
3.2 Interstitial lung disease
3.3 Other pulmonary diseases with mixed restrictive and obstructive pattern
3.4 Sleep disordered breathing
3.5 Alveolar hypoventilation disorders
3.6 Chronic exposure to high altitude
3.7 Developmental abnormalities
Group 4: Chronic thromboembolic pulmonary hypertension
Group 5: Pulmonary hypertension with unclear and/or multifactorial mechanisms
5.1 Hematological disorders: myeloproliferative disorders, splenectomy
5.2 Systemic disorders: sarcoidosis, pulmonary Langerhans cell hystiocitosis, lymphangioleiomyomatosis, neurofibromatosis, vasculitis
5.3 Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders
5.4 Others: tumoural obstruction, fibrosing mediastinitis, chronic renal failure on dialysis