Pulmonary arteriovenous fistula is an abnormal connection between an artery and vein in the lungs. As a result, blood passes through the lungs without receiving enough oxygen. It also acts as a detour, sidestepping the normal route the blood is supposed to take. If a patient has symptoms or problems, medical attention is essential.
Pulmonary arteriovenous fistulas are congenital malformations—that is, they’re present at birth. They appear slightly more often in females than in males. Pulmonary arteriovenous fistulas more commonly appear on their own, independent of an underlying disease. Fistulas also can be a complication of liver disease or lung injury, although this is much less common.