title: Impact of microembolism and hemodynamic changes in the brain during carotid endarterectomy.
abstract: OBJECTIVE
  Monitoring of carotid endarterectomy with electroencephalography and transcranial Doppler ultrasonography provides instantaneous information about hemodynamic changes and embolic signals. However, a relation between these findings and intraoperative infarcts has not yet been demonstrated.
  
  
  METHODS
  In this study we compared preoperative and post-operative computed tomographic scans (58 patients) or magnetic resonance imaging (40 patients) of the brain, assessed by two independent observers, to detect intraoperative infarcts, and we related any such new lesions to the findings of intraoperative monitoring.
  
  
  RESULTS
  In the computed tomography series one intraoperative infarct occurred, with corresponding clinical deficits. In the magnetic resonance group four patients developed new lesions that occurred intraoperatively, all of which were clinically silent. There was a significant relation between the number of embolic signals during the surgical dissection of the carotid artery and the occurrence of intraoperative infarcts (P < .005). Three of the four infarcts were of the lacunar type; the fourth patient had a border-zone infarct, associated not only with many embolic signals but also with low flow during cross-clamping. There were no demonstrable ultrasound side effects on brain tissue.
  
  
  CONCLUSIONS
  Embolic signals detected by transcranial Doppler monitoring in the dissection phase of carotid endarterectomy show a significant relation to new ischemic lesions and therefore are potentially harmful. The phenomenon should alert the vascular surgeon.
authors.affiliation: Department of Clinical Neurophysiology, St Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Jansen
authors.forename: L M
authors.initials: LM
authors.lastname: Ramos
authors.forename: J P
authors.initials: JP
authors.lastname: van Heesewijk
authors.forename: F L
authors.initials: FL
authors.lastname: Moll
authors.forename: J
authors.initials: J
authors.lastname: van Gijn
authors.forename: R G
authors.initials: RG
authors.lastname: Ackerstaff
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000503:physiopathology*; D002545:Brain Ischemia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D016893:Carotid Stenosis / Q000601:surgery; D002560:Cerebrovascular Circulation; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D007431:Intraoperative Complications / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis; D011300:Preoperative Care; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial