Bilateral subclavian steal syndrome.

Two cases of bilateral subclavian steal syndrome are presented, demonstrating complete occlusion at the origin of both subclavian arteries with distal reconstitution via reversal of blood flow through the vertebrobasilar system. Since unsuspected subclavian artery obstruction may present significant angiographic hazard, careful physical examination including blood pressures in both upper extremities and auscultation of the neck is necessary in order to avoid undesirable complications.