ABSTRACT
Anatomy and pathophysiology Pulmonary arteriovenous fistulas (PAVFs) or pulmonary arteriovenous malformations (PAVMs) are now usually classified either as simple or complex based on the angiographic findings1 (Figure 45.1). Simple PAVMs are more common (80%) and have a single feeding artery and vein which is usually larger with a non-septated aneurysmal sac. Complex PAVMs have multiple feeding arteries.1 The malformation then is cirsoid with multiple septations and there can be more than one draining vein. PAVMs may be solitary or multiple, which occurs more commonly when they are associated with hereditary hemorrhagic telangiectasia (HHT).2 If PAVMs are of significant size then significant right to left shunting will occur, which is associated with desaturation, hypoxia, and polycythemia.3
