title: Microemboli in patients with vertebrobasilar ischemia: association with vertebrobasilar and cardiac lesions.
abstract: OBJECTIVE
  Microembolic high-intensity transient signals (HITS) on transcranial Doppler ultrasound (TCD) are associated with carotid stenosis, artificial heart valves, and other cardiac conditions. Only one case report describes stroke-related HITS in the posterior cerebral circulation. This study was designed to assess prospectively the prevalence of asymptomatic microemboli in vertebrobasilar ischemia and to determine whether potential cardioembolic sources, vertebral or basilar occlusive disease, and infarct subtypes predict the detection of HITS.
  
  
  METHODS
  We investigated 52 consecutive patients with acute or recent vertebrobasilar ischemia within 48 hours after admission. TCD monitoring was performed according to established criteria for 20 minutes on each posterior cerebral artery. Fetal origin of the posterior cerebral artery was an exclusion criterion and ruled out by carotid compression.
  
  
  RESULTS
  Microembolic signals were detected in 10 patients (19.2%). In a multivariate logistic regression analysis that included all independent variables, potential cardiac sources were significantly associated with HITS (odds ratio [OR], 14.3; 95% confidence interval [CI], 1.6 to 128.4), in particular when more than one cardiac abnormality (OR, 32.7; CI, 4.1 to 259.3) or a high-risk source (OR, 14.0; 95% CI, 2.3 to 84.9) was found. Vertebrobasilar vessel lesions and infarct subtype were not related to the detection of microemboli.
  
  
  CONCLUSIONS
  Cardiac sources of embolism are a determinant of HITS in posterior cerebral circulation ischemia, suggesting that cardioembolic infarcts in that territory might be more common than suspected. Vertebrobasilar vessel abnormalities are less likely to lodge microemboli, which may indicate histopathological changes different from carotid artery disease.
authors.affiliation: Neurological Institute, Department of Neurology, Columbia-Presbyterian Medical Center, New York, NY 10032, USA. hck8@columbia.edu
authors.forename: H C
authors.initials: HC
authors.lastname: Koennecke
authors.forename: H
authors.initials: H
authors.lastname: Mast
authors.forename: S S
authors.initials: SS
authors.lastname: Trocio
authors.forename: R L
authors.initials: RL
authors.lastname: Sacco
authors.forename: J L
authors.initials: JL
authors.lastname: Thompson
authors.forename: J P
authors.initials: JP
authors.lastname: Mohr
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D002544:Cerebral Infarction / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology; D004617:Embolism / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D011446:Prospective Studies; D012189:Retrospective Studies; D014463:Ultrasonography; D014715:Vertebrobasilar Insufficiency / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology