1999 Resident Poster Competition
Kirk Chan-Tack M.D.
University of Missouri-- Columbia
Subclavian Steal Syndrome: A Rare But Important Cause of Syncope
Subclavian steal syndrome is caused by occlusion of the proximal subclavian artery with subsequent retrograde filling of the subclavian artery via the vertebral artery. The decreased blood flow to the brain and upper extremity on the affected side can be manifested in a variety of symptoms due to (1) vertebrobasilar insufficiency or (2) ischemia of the affected extremity. Vertebrobasilar insufficiency may produce lightheadedness, dizziness, vertigo, ataxia, visual disturbances, motor deficits, focal seizures, confusion, aphasia, headache, or syncope. Symptoms due to ischemia of the affected extremity are less frequent and include weakness, paresthesias, or coldness on the affected side. Hypertension and vigorous exercise of the affected extremity are risk factors for subclavian steal syndrome.
A 79 year-old woman was admitted for evaluation of a syncopal episode. While climbing a flight of stairs, she turned her head to the left and abruptly passed out. She fell and sustained a left occipital laceration. The patient denied chest pain, palpitations, prodrome, visual changes or aura, tongue biting, bowel or bladder incontinence, and post-ictal state. She had no previous episodes of pre-syncope or syncope. Her past medical history was remarkable for type 2 diabetes and hyperlipidemia. Medications included prandin and lipitor. Temperature was 37.2°C, BP 141/65 (right arm) and 80/43 (left arm), heart rate 76 and regular, respiratory rate 16 breaths per minute. Positive physical findings included a 6cm left occipital laceration as well as non-palpable left radial and brachial pulses that were detectable only by Doppler. Complete blood count, chemistry panel (including cardiac enzymes and troponin), EKG, and chest x-ray were normal. Head CT was negative fore bleed, infarct, and mass effect. Carotid duplex study showed reverse flow in the left vertebral artery and abnormal, stenotic distal left subclavian artery. MRI angiography confirmed complete occlusion of the left subclavian artery with classic subclavian steal. The patient underwent a percutaneous tranSt. Louis University minal angioplasty with stenting of the left subclavian artery. She tolerated the procedure without complications, was discharged on the following day, and has done well through 5 months of follow-up. This case underscores the importance of subclavian steal syndrome as well as it's morbidity and potential for mortality if undiagnosed or misdiagnosed. Recognition is crucial since patients can be successfully treated by surgery.
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Alan D Forker, MD MACP
Missouri Chapter Governor
Patrick Mills
Missouri Chapter Executive Director
