Definition:

Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) are rare diseases that are classified as a subgroup of pulmonary arterial hypertension (PAH). PVOD is histologically characterized by intimal fibrosis that narrows and occludes pulmonary veins and it accounts for 5-10% of cases initially thought to be idiopathic PAH (IPAH). PCH is histologically characterized by localized capillary proliferation within the lung in which capillaries invade the pulmonary interstitium, vessels and, less commonly, airways. PCH has been reported to be much less frequent than PVOD. In recent years, PAH-targeted drugs including epoprostenol have improved the survival of patients with IPAH. PVOD/PCH has a very similar clinical presentation to PAH but is characterised by a worse prognosis and the possibility that severe pulmonary oedema can develop with specific PAH therapy. PVOD associated with a BMPR2 mutation has been reported. Recently, it has been suggested that EIF2AK4 mutations are the major cause of heritable PVOD.