title: Prediction of Cerebral Hyperperfusion Syndrome with Velocity Blood Pressure Index.
abstract: BACKGROUND
  Cerebral hyperperfusion syndrome is an important complication of carotid endarterectomy (CEA). An >100% increase in middle cerebral artery velocity (MCAV) after CEA is used to predict the cerebral hyperperfusion syndrome (CHS) development, but the accuracy is limited. The increase in blood pressure (BP) after surgery is a risk factor of CHS, but no study uses it to predict CHS. This study was to create a more precise parameter for prediction of CHS by combined the increase of MCAV and BP after CEA.
  
  
  METHODS
  Systolic MCAV measured by transcranial Doppler and systematic BP were recorded preoperatively; 30 min postoperatively. The new parameter velocity BP index (VBI) was calculated from the postoperative increase ratios of MCAV and BP. The prediction powers of VBI and the increase ratio of MCAV (velocity ratio [VR]) were compared for predicting CHS occurrence.
  
  
  RESULTS
  Totally, 6/185 cases suffered CHS. The best-fit cut-off point of 2.0 for VBI was identified, which had 83.3% sensitivity, 98.3% specificity, 62.5% positive predictive value and 99.4% negative predictive value for CHS development. This result is significantly better than VR (33.3%, 97.2%, 28.6% and 97.8%). The area under the curve (AUC) of receiver operating characteristic: AUC(VBI) = 0.981, 95% confidence interval [CI] 0.949-0.995; AUC(VR) = 0.935, 95% CI 0.890-0.966, P = 0.02.
  
  
  CONCLUSIONS
  The new parameter VBI can more accurately predict patients at risk of CHS after CEA. This observation needs to be validated by larger studies.
authors.forename: Zhi-Chao
authors.initials: ZC
authors.lastname: Lai
authors.forename: Bao
authors.initials: B
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: Leng
authors.initials: L
authors.lastname: Ni
authors.affiliation: Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing 100730, China.
authors.forename: Chang-Wei
authors.initials: CW
authors.lastname: Liu
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D016894:Endarterectomy, Carotid; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies