Renal arteriovenous fistulas are unusual lesions with a variety of cli
nical manifestations. Congenital and acquired forms have been treated
successfully with transcatheter embolization for 2 decades. In the cas
e of large aneurysmal lesions the risk of inadvertent pulmonary emboli
sm has traditionally precluded this approach and necessitated open sur
gery. However, with refinements in angiographic equipment and techniqu
e, such an approach is now feasible and desirable.