title: Middle cerebral artery pulsatility index and cognitive improvement after carotid endarterectomy for symptomatic stenosis.
abstract: OBJECTIVE
  Transcranial Doppler (TCD) is frequently used to evaluate peripheral cerebral resistance and cerebral blood flow (CBF) in the middle cerebral artery prior to and during carotid endarterectomy (CEA). Patients with symptomatic carotid artery stenosis may have reduced peripheral cerebral resistance to compensate for inadequate CBF. The authors aim to determine whether symptomatic patients with reduced peripheral cerebral resistance prior to CEA demonstrate increased CBF and cognitive improvement as early as 1 day after CEA.
  
  
  METHODS
  Fifty-three patients with symptomatic CEA were included in this observational study. All patients underwent neuropsychometric evaluation 24 hours or less preoperatively and 1 day postoperatively. The MCA was evaluated using TCD for CBF mean velocity (MV) and pulsatility index (PI). Pulsatility index ≤ 0.80 was used as a cutoff for reduced peripheral cerebral resistance.
  
  
  RESULTS
  Significantly more patients with baseline PI ≤ 0.80 exhibited cognitive improvement 1 day after CEA than those with PI > 0.80 (35.0% vs 6.1%, p = 0.007). Patients with cognitive improvement had a significantly greater increase in CBF MV than patients without cognitive improvement (13.4 ± 17.1 cm/sec vs 4.3 ± 9.9 cm/sec, p = 0.03). In multivariate regression model, a baseline PI ≤ 0.80 was significantly associated with increased odds of cognitive improvement (OR 7.32 [1.40-59.49], p = 0.02).
  
  
  CONCLUSIONS
  Symptomatic CEA patients with reduced peripheral cerebral resistance, measured as PI ≤ 0.80, are likely to have increased CBF and improved cognitive performance as early as 1 day after CEA for symptomatic carotid artery stenosis. Revascularization in this cohort may afford benefits beyond prevention of future stroke. Clinical trial registration no: NCT00597883 ( ClinicalTrials.gov ).
authors.affiliation: Departments of Anesthesiology.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Heyer
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Mergeche
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology / Q000601:surgery*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003071:Cognition; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009483:Neuropsychological Tests; D011184:Postoperative Period; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial; D014655:Vascular Resistance / Q000502:physiology