title: Incident stroke is associated with common carotid artery diameter and not common carotid artery intima-media thickness.
abstract: OBJECTIVE
  The common carotid artery interadventitial diameter is measured on ultrasound images as the distance between the media-adventitia interfaces of the near and far walls. It is associated with common carotid intima-media thickness (IMT) and left ventricular mass and might therefore also have an association with incident stroke.
  
  
  METHODS
  We studied 6255 individuals free of coronary heart disease and stroke at baseline with mean age of 62.2 years (47.3% men), members of a multiethnic community-based cohort of whites, blacks, Hispanics, and Chinese. Ischemic stroke events were centrally adjudicated. Common carotid artery interadventitial diameter and IMT were measured. Cases with incident atrial fibrillation (n=385) were excluded. Multivariable Cox proportional hazards models were generated with time to ischemic event as outcome, adjusting for risk factors.
  
  
  RESULTS
  There were 115 first-time ischemic strokes at 7.8 years of follow-up. Common carotid artery interadventitial diameter was a significant predictor of ischemic stroke (hazard ratio, 1.86; 95% confidence interval, 1.59-2.17 per millimeter) and remained so after adjustment for risk factors and common carotid IMT with a hazard ratio of 1.52/mm (95% confidence interval, 1.22-1.88). Common carotid IMT was not an independent predictor after adjustment (hazard ratio, 0.14; 95% confidence interval, 0.14-1.19).
  
  
  CONCLUSIONS
  Although common carotid IMT is not associated with stroke, interadventitial diameter of the common carotid artery is independently associated with first-time incident ischemic stroke even after adjusting for IMT. Our hypothesis that this is in part attributable to the effects of exposure to blood pressure needs confirmation by other studies.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov. Unique identifier: NCT00063440.
authors.affiliation: From the Department of Radiology, Tufts University School of Medicine, Boston, MA (J.F.P.); Department of Neurology, University of Miami, FL (R.L.S.); Division of Cardiology (W.S.P.) and Department of Medicine (W.S.P., D.V.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Neurology, Wake Forest School of Medicine, Winston-Salem, NC (M.K.A.); and Department of Radiology, Saint Elizabeth's Medical Center, Brighton, MA (D.H.O.).
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Polak
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Sacco
authors.forename: Wendy S
authors.initials: WS
authors.lastname: Post
authors.forename: Dhananjay
authors.initials: D
authors.lastname: Vaidya
authors.forename: Martinson Kweku
authors.initials: MK
authors.lastname: Arnan
authors.forename: Daniel H
authors.initials: DH
authors.lastname: O'Leary
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000453:epidemiology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000473:pathology; D059168:Carotid Intima-Media Thickness; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*
keywords: carotid arteries; risk factors; stroke; ultrasonography