Subclavian steal syndrome is a vascular disorder that consists of significant blood supply restriction with resultant insufficiency of the vertebrobasilar artery and the subclavian artery causing symptomatic insufficiency to the brain and upper extremity. It is important to recognize this condition in patients with subacute to chronic posterior circulation vascular insufficiency as early diagnosis and treatment can have good clinical outcomes.

A 60-year-old woman presented with subacute progressive vertigo, binocular diplopia, and gait ataxia. On examination, the patient noted to have horizontal gaze nystagmus, mild gait ataxia, upper and lower extremity ataxia worse on the right side. Head CT and brain MRI were normal without any evidence for acute ischemic changes on diffusion-weighted imaging. CTA of the head and neck revealed complete occlusion of the left subclavian artery distal to its origin and proximal to the left vertebral artery origin. Metabolic, autoimmune, infectious, paraneoplastic, and neoplastic workup was negative. The patient’s symptoms persisted for over two months without any improvement. She underwent left carotid artery to subclavian artery bypass with complete resolution of neurological symptoms.

We present an unusual case of subclavian steal syndrome presenting with chronic vertebrobasilar insufficiency that improved after surgical revascularization.  Subclavian steal syndrome is a vascular disorder that consists of significant blood supply restriction with resultant insufficiency of the vertebrobasilar artery and the subclavian artery causing symptomatic insufficiency to the brain and upper extremity. It is important to recognize this condition in patients with subacute to chronic posterior circulation vascular insufficiency as early diagnosis and treatment can have good clinical outcomes.