|Group 1||Pulmonary arterial hypertension (PAH).
Examples: idiopathic, familial, drug and toxin induced, collagen vascular disease, congenital left to right shunts, HIV, portal hypertension, schistosomiasis, chronic hemolytic anemia, pulmonary venoocclusive disease, pulmonary capillary hemangiomatosis.|
|Group 2 ||Pulmonary hypertension owing to left heart disease.
Examples: chronic severe left sided valve disease, left ventricular severe systolic, or diastolic heart failure.|
|Group 3||Pulmonary hypertension owing to lung diseases and/or hypoxia.
Examples: COPD, interstitial lung disease, sleep-disordered breathing, alveolar hypoventilation, chronic exposure to high altitudes.|
|Group 4||Chronic thromboembolic pulmonary hypertension (CTEPH).
Examples: thrombotic obstruction of the pulmonary arteries.|
|Group 5 ||Pulmonary hypertension with unclear multifactorial mechanisms.
Examples: myeloproliferative disorders, splenectomy, sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, neurofibromatosis, vasculitis, thyroid disease, fibrosing mediastinitis, chronic renal failure on dialysis, tumor obstruction, glycogen storage disease.|