Endovascular Treatment of Vertebral Artery Steal Syndrome from an Arteriovenous Fistula Between the Internal Mammary Artery and Superior Vena Cava

Vertebrobasilar insufficiency resulting from subclavian steal syndrome and high flow through hemodialysis fistulas has been described. The present report describes a case of vertebral artery steal syndrome from an arteriovenous (AV) fistula between the right internal mammary artery and superior vena cava with the unusual pattern of antegrade flow through the vertebral artery in the setting of classic symptoms of steal. The AV fistula likely developed during earlier cardiac catheterizations. The patient presented with progressively worsening gait and limb ataxia. Angiography demonstrated the AV fistula and antegrade flow through the vertebral artery. Coil embolization of this high-flow fistula resulted in complete resolution of symptoms.