title: Determinants of carotid microembolization.
abstract: OBJECTIVE
  Earlier studies have highlighted risk factors for perioperative stroke after carotid endarterectomy, such as female sex, preoperative symptoms, and cerebral infarction. In this study, we investigated the relationship between these factors and perioperative microembolization.
  
  
  METHODS
  A total of 235 patients were entered in the study at two centers. Transcranial Doppler ultrasound scanning was possible in 190 patients (81%) and was performed for 1 hour preoperatively and continuously intraoperatively as a means of detecting microemboli and monitoring mean middle cerebral artery velocity. The findings of transcranial Doppler ultrasound scanning were related to perioperative risk factors by means of univariate analysis.
  
  
  RESULTS
  Microemboli were detected in 28 (15%), 79 (42%), and 98 (52%) patients preoperatively, during carotid artery dissection, and after closure of the artery, respectively. Having 10 or more emboli after carotid artery closure was more common in women (P = .04) and in patients with symptomatic carotid artery disease (P = .04) and was demonstrated in three of the six patients who had a perioperative stroke. These three patients also had preoperative evidence of cerebral infarction and an intraoperative middle cerebral artery velocity less than 40 cm/s.
  
  
  CONCLUSIONS
  In this study, perioperative microembolization was more common in women and patients with symptomatic carotid artery disease. These findings may explain the increased risk of carotid surgery in these patients.
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Charing Cross Hospital, London, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Golledge
authors.forename: R
authors.initials: R
authors.lastname: Gibbs
authors.forename: C
authors.initials: C
authors.lastname: Irving
authors.forename: G
authors.initials: G
authors.lastname: Clayton
authors.forename: D
authors.initials: D
authors.lastname: Bond
authors.forename: R M
authors.initials: RM
authors.lastname: Greenhalgh
authors.forename: P
authors.initials: P
authors.lastname: Lamont
authors.forename: A H
authors.initials: AH
authors.lastname: Davies
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000145:classification / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D016343:Monitoring, Intraoperative / Q000379:methods; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D020521:Stroke / Q000145:classification / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial