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Subclavian Steal syndrome
fromNew England Journal of Medicine
Subclavian steal syndrome (SSS), also called subclavian steal phenomenon or subclavian steal steno-occlusive disease, is a constellation of signs and symptoms that arise from retrograde (reversed) flow of blood in the vertebral artery or the internal thoracic artery, due to a proximal stenosis (narrowing) and/or occlusion of the subclavian artery.
Classically, SSS is a consequence of a redundancy in the circulation of the brain and the flow of blood.
SSS results when the short low resistance path (along the subclavian artery) becomes a high resistance path (due to narrowing) and blood flows around the narrowing via the arteries that supply the brain (left and right vertebral artery, left and right internal carotid artery). The blood flow from the brain to the upper limb in SSS is considered to be stolen as it is blood flow the brain must do without.
As in vertebral-subclavian steal, coronary-subclavian steal may occur in patients who have received a coronary artery bypass graft using the internal thoracic artery (ITA). As a result of this procedure, the distal end of the ITA is diverted to one of the coronary arteries (typically the LAD), facilitating blood supply to the heart. In the setting of increased resistance in the proximal subclavian artery, blood may flow backward away from the heart along the ITA causing myocardial ischemia. Vertebral-subclavian and coronary-subclavian steal can occur concurrently in patients with an ITA CABG.