title: Pseudo subclavian steal syndrome: Case report.
abstract: BACKGROUND
  Vertebrobasilar insufficiency (VBI) is a condition that results from restricted blood flow to the posterior portions of the brain, which are primarily served by the vertebral and basilar arteries. It is the most common cause of vertigo in the elderly and is usually accompanied by impaired vision and sensation. Congenital abnormalities, atherosclerosis, stroke and/or trauma may all lead to decreased vertebrobasilar circulation. A syndrome called Subclavian Steal Syndrome (SSS), which manifests with similar neurological symptoms but with a different pathophysiology, may also cause VBI.
  
  
  METHODS
  A middle-aged female presented with gradual onset fainting and vertigo attacks. Cardiac, auditory and autonomic etiologies were investigated and excluded. Clinical findings and presentation were highly suggestive of subclavian steal. However, subsequent CT angiography showed normal subclavian arteries. Instead, findings included a persistent right trigeminal artery (PTA), stenosis of the right proximal internal carotid artery, atresis of the left vertebral artery and distal segment of right vertebral artery, congenitally compromised changes in vertebral circulation (bilateral absence of the posterior communicating arteries (PCOMs)) and an absent anterograde vertebrobasilar circulation. Symptoms resolved after carotid endarterectomy.
  
  
  CONCLUSIONS
  Due to the absence of a normally developed posterior circulation, the PTA was the main source of blood supply for the patient. Development of recent artheromatous changes in the right internal carotid artery, however, resulted in decreased blood through PTA, further compromising posterior circulation. This resulted in vertebrobasilar insufficiency, and manifested in symptomology similar to SSS.
  
  
  CONCLUSIONS
  This clinical encounter illustrates the relative contribution of anatomical and vasoocclusive factors in closely mimicking symptoms of subclavian steal syndrome.
authors.affiliation: Department of Neurosurgery, Baylor Scott and White Health Care, Temple, TX 76508, USA.
authors.forename: Sneha
authors.initials: S
authors.lastname: Konda
authors.affiliation: Department of Neurosurgery, Baylor Scott and White Health Care, Temple, TX 76508, USA. Electronic address: sdayawansa@sw.org.
authors.forename: Samantha
authors.initials: S
authors.lastname: Dayawansa
authors.affiliation: Department of Neurosurgery, Baylor Scott and White Health Care, Temple, TX 76508, USA.
authors.forename: Soren
authors.initials: S
authors.lastname: Singel
authors.affiliation: Department of Neurosurgery, Baylor Scott and White Health Care, Temple, TX 76508, USA.
authors.forename: Jason H
authors.initials: JH
authors.lastname: Huang
keywords: Carotid atherosclerosis; Persistent trigeminal artery; Syncope attacks