Collateralization of the palmar arch by a failing radiocephalic fistula: an underappreciated complication of Cimino fistula anatomy.

Stenosis at the anastomosis of an arteriovenous dialysis fistula can cause fistula failure due to venous thrombosis. Three cases are presented in which anastomotic stenosis in radiocephalic fistulas resulted in radial artery occlusion with collateralization of ulnar artery flow across the palmar arch. Hand ischemia did not occur, and reductions in fistula efficiency were clinically subtle. Urea kinetics were compromised, and a characteristic palmar bruit was heard.