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Missouri Resident Poster Competition 1999
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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