Coronary-subclavian steal.

Of 450 patients undergoing internal mammary artery grafts for coronary artery bypass, proximal subclavian artery stenosis with reversal of flow in the internal mammary and vertebral arteries ("coronary-subclavian steal") subsequently developed in two patients. Carotid-subclavian bypass successfully reestablished antegrade blood flow in the ipsilateral internal mammary and vertebral arteries in both patients. Arch aortography is indicated preoperatively in myocardial revascularization patients in the presence of cerebrovascular symptoms, upper extremity blood pressure gradients, and carotid or subclavian bruits. Should subclavian artery stenosis develop subsequent to myocardial revascularization, carotid-subclavian or acillary-axillary bypass can effectively restore antegrade blood flow and reverse the coronary-subclavian steal.