title: Changes in middle cerebral artery velocity after carotid endarterectomy do not identify patients at high-risk of suffering intracranial haemorrhage or stroke due to hyperperfusion syndrome.
abstract: OBJECTIVE
  To determine if significant increases in middle cerebral artery velocity (MCAV) or pulsatility index (PI) during and immediately after carotid endarterectomy (CEA) were predictive of patients suffering a stroke due to the hyperperfusion syndrome (HS) or intracerebral haemorrhage (ICH).
  
  
  METHODS
  Transcranial Doppler (TCD) mean/peak MCAV and PI were recorded pre-operatively; pre-clamp; 1-min post-declamping; 10-min post-declamping and 30-min post-operatively. The study was divided into two time periods; Group 1 (1995-2007); where there was no formal guidance for managing post-CEA hypertension (PEH) and Group 2 (2008-2012); where written guidelines for treating PEH were available.
  
  
  RESULTS
  11/1024 patients in Group 1 (1.1%) suffered a stroke due to HS/ICH, compared to 0/426 patients (0.0%) in Group 2 (p = 0.02). In Group 1; intra-operative increases >100% in mean/peak MCAV and PI at 1 and 10-min post-clamp release had positive predictive values (PPV) of 1.2%, 6.3% and 20.0% and 2.9%, 8.0% and 16.6% respectively. Post-operatively; a >100% increase in mean and peak MCAV had a PPV of 6.3% and 2.7% respectively.
  
  
  CONCLUSIONS
  We were unable to demonstrate that significant increases in MCAV and PI were able to predict patients at increased risk of suffering a post-operative stroke due to HS or ICH. The provision of written guidance for managing PEH in Group 2 patients was associated with virtual abolition of ICH/HS.
authors.affiliation: Department of Vascular Surgery at Leicester Royal Infirmary, Leicester, UK. jn139@le.ac.uk
authors.forename: J E
authors.initials: JE
authors.lastname: Newman
authors.forename: M
authors.initials: M
authors.lastname: Ali
authors.forename: R
authors.initials: R
authors.lastname: Sharpe
authors.forename: M J
authors.initials: MJ
authors.lastname: Bown
authors.forename: R D
authors.initials: RD
authors.lastname: Sayers
authors.forename: A R
authors.initials: AR
authors.lastname: Naylor
mesh_terms: D001783:Blood Flow Velocity; D002340:Carotid Artery Diseases / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D002560:Cerebrovascular Circulation; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D006801:Humans; D020343:Hypertensive Encephalopathy / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D020300:Intracranial Hemorrhages / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial