title: Cerebral vasoreactivity and internal carotid artery flow help to identify patients at risk for hyperperfusion after carotid endarterectomy.
abstract: OBJECTIVE
  Hyperperfusion syndrome is a rare but potentially devastating complication after carotid endarterectomy (CEA). The aim of this study was to investigate whether preoperative measurement of cerebral vasoreactivity (CVR) and intraoperative measurement of internal carotid artery (ICA) flow could identify patients at risk for hyperperfusion after CEA.
  
  
  METHODS
  For 26 patients with unilateral ICA stenosis >/=70%, cerebral blood flow (CBF) and CVR were investigated before and 1 month after CEA, with resting and acetazolamide-challenge single-photon emission CT. CBF on the first postoperative day was also measured. ICA flow was measured before and after reconstruction by electromagnetic flowmeter during surgery.
  
  
  RESULTS
  Ipsilateral CBF on the first postoperative day significantly increased relatively (56.6+/-53.2%) as well as absolutely (37.9+/-8.8 to 57.7+/-18.0 mL/100 g per minute) in the reduced CVR group (CVR <12%) but not in the normal CVR group (CVR >/=12%) (10.3+/-15.5% and 40.6+/-7.9 to 43.9+/-5.7 mL/100 g per minute, respectively). One month later, this difference almost disappeared. Two patients showed ipsilateral CBF increase of >/=100%. A significant association of intracerebral steal with hyperperfusion (CBF increase >/=100%) on the first postoperative day was also observed. ICA flow increase after reconstruction significantly correlated with CBF increase on the first postoperative day in the reduced CVR group but not in the normal CVR group. The threshold of ICA flow increase for hyperperfusion was estimated to be 330 mL/min in the reduced CVR group.
  
  
  CONCLUSIONS
  Single-photon emission CT with acetazolamide challenge and ICA flow measurement during surgery could identify patients at risk for hyperperfusion after CEA, in whom careful monitoring and control of blood pressure should be initiated even intraoperatively.
authors.affiliation: Department of Neurosurgery, Hyogo Brain and Heart Center, Himeji, Japan. khosoda@venus.dti.ne.jp
authors.forename: K
authors.initials: K
authors.lastname: Hosoda
authors.forename: T
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Shibata
authors.forename: M
authors.initials: M
authors.lastname: Kamei
authors.forename: K
authors.initials: K
authors.lastname: Kidoguchi
authors.forename: J
authors.initials: J
authors.lastname: Koyama
authors.forename: S
authors.initials: S
authors.lastname: Fujita
authors.forename: N
authors.initials: N
authors.lastname: Tamaki
mesh_terms: D000086:Acetazolamide; D000368:Aged; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000502:physiology*; D002560:Cerebrovascular Circulation; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D015427:Reperfusion Injury / Q000000981:diagnostic imaging / Q000209:etiology*; D012307:Risk Factors; D013577:Syndrome; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D000086:Acetazolamide