title: Can bruits distinguish high-grade from moderate symptomatic carotid stenosis? The North American Symptomatic Carotid Endarterectomy Trial.
abstract: OBJECTIVE
  To determine whether cervical bruits, alone or combined with other clinical characteristics, can distinguish high-grade (70% to 99%) carotid artery stenoses from less severe stenoses in patients with symptoms of cerebrovascular disease.
  
  
  METHODS
  Cross-sectional comparison of clinical observations with contemporaneous angiography.
  
  
  METHODS
  The North American Symptomatic Carotid Endarterectomy Trial (NASCET), a multicenter randomized controlled trial of carotid endarterectomy.
  
  
  METHODS
  All patients enrolled in the NASCET from its inception in 1988 to November 1991.
  
  
  RESULTS
  A focal ipsilateral carotid bruit had a sensitivity of 63% and a specificity of 61% for high-grade stenosis and, when absent, only lowered the probability for high-grade stenosis from a pretest value of 52% to a post-test probability of 40%. When combined with four other clinical characteristics (an infarction on computed tomography of the head, a carotid ultrasound scan suggesting more than 90% stenosis, a transient ischemic attack rather than a minor stroke as a qualifying event, and a retinal rather than a hemispheric qualifying event), the predicted probabilities of high-grade stenosis ranged from a low of 18% (when none of the features was present) to a high of 94% (when all the features were present.
  
  
  CONCLUSIONS
  Cervical bruits alone were not sufficiently predictive of high-grade symptomatic carotid stenosis to be useful in selecting patients for angiography; they were absent in over one third of patients with high-grade stenosis. When combined with other clinical variables, patients with high or low probabilities of 70% to 99% stenoses could be identified, but this prediction model still missed many individuals with high-grade stenosis, even in this training set of selected patients.
authors.affiliation: McMaster University, Hamilton, Ontario, Canada.
authors.forename: J S
authors.initials: JS
authors.lastname: Sauvé
authors.forename: K E
authors.initials: KE
authors.lastname: Thorpe
authors.forename: D L
authors.initials: DL
authors.lastname: Sackett
authors.forename: W
authors.initials: W
authors.lastname: Taylor
authors.forename: H J
authors.initials: HJ
authors.lastname: Barnett
authors.forename: R B
authors.initials: RB
authors.lastname: Haynes
authors.forename: A J
authors.initials: AJ
authors.lastname: Fox
mesh_terms: D000792:Angiography / Q000191:economics; D001314:Auscultation; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002561:Cerebrovascular Disorders / Q000150:complications; D003365:Costs and Cost Analysis; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000150:complications; D008297:Male; D011237:Predictive Value of Tests; D012044:Regression Analysis; D012680:Sensitivity and Specificity