title: Predicting hemodynamic ischemia by transcranial Doppler monitoring during therapeutic balloon occlusion of the internal carotid artery.
abstract: OBJECTIVE
  Our objective was to evaluate the sensitivity of transcranial Doppler (TCD) sonographic monitoring during permanent balloon occlusion of the internal carotid artery (ICA) in predicting hemodynamic ischemia.
  
  
  METHODS
  Thirty-two consecutive patients underwent controlled therapeutic balloon occlusion of the ICA. Selection criteria included assessment of the circle of Willis by compression angiography, clinical tolerance during a 20-minute test occlusion, and TCD monitoring of the ipsilateral middle cerebral artery. The mean blood flow velocity (MBFV) (n = 32) and pulsatility index (PI) (n = 28) were recorded. In 25 patients, MBFV changes upon motor stimulation were recorded before and after ICA occlusion.
  
  
  RESULTS
  Twenty-eight (88%) of the patients had no complications. Three patients suffered delayed symptoms 30 minutes to 20 hours after balloon detachment. Two of these patients recovered spontaneously within 1 day, the other improved after extracranial/intracranial (EC/IC) bypass surgery. One patient, who did not tolerate the test occlusion, suffered a hemodynamic stroke despite EC/IC bypass before permanent balloon occlusion. No embolic complications occurred. The mean MBFV reduction was 20% (range, 0% to 55%); the mean PI reduction was 20% (range, 0% to 56%). No complications occurred in patients who had mild MBFV and PI reduction (30% or less, n = 21). All three patients with severe MBFV or PI reduction (> 50%) had neurologic symptoms. Among those with moderate MBFV or PI reduction (30% to 50%, n = 8), symptoms developed in only one patient who had moderate reduction of both MBFV (33%) and PI (38%). Motor vasoreactivity showed wide variation and was markedly reduced in two symptomatic patients.
  
  
  CONCLUSIONS
  TCD monitoring reflects changes in cerebral hemodynamics after therapeutic balloon occlusion of the ICA. MBFV and PI reductions under 30% are highly predictive of clinical tolerance. A reduction of more than 50% may be a critical threshold for the occurrence of symptoms; in such cases, EC/IC bypass should be considered before proceeding with permanent balloon occlusion.
authors.affiliation: Department of Neuroradiology, University Hospital of Hamburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Eckert
authors.forename: A
authors.initials: A
authors.lastname: Thie
authors.forename: M
authors.initials: M
authors.lastname: Carvajal
authors.forename: C
authors.initials: C
authors.lastname: Groden
authors.forename: H
authors.initials: H
authors.lastname: Zeumer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology*; D002340:Carotid Artery Diseases / Q000628:therapy*; D002343:Carotid Artery, Internal; D002404:Catheterization / Q000009:adverse effects*; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D004621:Embolization, Therapeutic / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005544:Forecasting; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D017585:Ultrasonography, Doppler, Transcranial