Pulmonary arteriovenous fistula is a condition in which an abnormal connection (fistula) develops between an artery and vein in the lungs. As a result, blood passes through the lungs without receiving enough oxygen.
Arteriovenous malformation - pulmonary
Causes, incidence, and risk factors
Pulmonary arteriovenous fistulas are usually the result of a genetic (inherited) disease that causes the blood vessels of the lung to develop abnormally. Fistulas also can be a complication of liver disease.
Patients with Rendu-Osler-Weber disease (ROWD) -- also called hereditary hemorrhagic telangiectasis (HHT) -- often have abnormal blood vessels in many parts of the body.