Subclavian Steal Syndrome Secondary to Isolated Innominate Artery Stenosis Possibly Due to Fibromuscular Dysplasia

Subclavian steal syndrome is usually associated with proximal subclavian artery stenosis and is characterized by retrograde perfusion of the vertebral artery to the distal subclavian artery. We encountered an unusual case of transient ischemic attack associated with isolated proximal innominate artery stenosis and angiographic subclavian steal phenomenon. Web-like stenosis found in the innominate artery could represent fibromuscular dysplasia. The patient was treated with an aortoinnominate artery bypass, with successful symptomatic relief.