The World Health Organization classification of pulmonary
hypertension [33]:
Group 1- Pulmonary arterial hypertension
Group 5- PH of unclear or multifactoral mechanisms
Group 1- Pulmonary arterial hypertension
Idiopathic PHGroup 2- PH due to left heart disease
Drug or toxin induced (Fenfluramine, Dexfenfluramine, Amphetamines, L-trytophan)
Associated with connective tissue disease
Associated with HIV
Associated with portal HTN
Associated with congenital heart disease
Associated with chronic hemolytic anemia
Associated with schistosomiasis
Pulmonary veno-occlusive disease
Pulmonary capillary hemangiomatosis
Systolic dysfunctionGroup 3- PH due to lung disease or hypoxia
Diastolic dysfunction
Valvular disease
COPDGroup 4- Chronic thromboembolic PH
Interstitial drug disease
Sleep-breathing disorder
Alveolar hypoventilation disorders
Chronic exposure to high altitude
Group 5- PH of unclear or multifactoral mechanisms
Hematologic disorders: myeloproliferative disorders, splenectomy
Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders
Systemic disorders: sarcoidosis, pulmonary Langerhans cell histiocytosis, lympahngioleiomyomatosis, vasculitis, neurofibromatosis
Other: tumoral obstruction, fibrosing mediastinitis, chronic renal failure while receiving dialysis
