title: Changes in cerebral hemodynamic and cognitive parameters after external carotid-internal carotid bypass surgery in patients with severe steno-occlusive disease: a pilot study.
abstract: BACKGROUND
  The direct impact of external carotid-internal carotid (EC-IC) bypass surgery on cognition of patients with severe steno-occlusive disease of internal carotid (ICA) or middle cerebral artery (MCA) is unknown. In this pilot study, we evaluated changes in cerebral hemodynamic and cognition in these patients.
  
  
  METHODS
  Patients with severe steno-occlusive disease and impaired cerebral vasodilatory reserve (CVR) with transcranial Doppler (TCD) breath holding index (BHI) and acetazolamide-challenged HMPAO-Single Photon Emission Tomographic (SPECT) imaging were offered EC-IC bypass surgery. CVR and cognitive performance using a formal neuropsychological battery were evaluated before and 3-6 months after surgery.
  
  
  RESULTS
  Nine patients and 9 matched controls were recruited. Significant CVR improvement from TCD-BHI [median 0 (Inter-quartile range IQR 0.45) to 1.10 (IQR 0.73), p<0.001] and SPECT (p<0.001) was observed in surgery patients. EC-IC bypass patients had significant improvement in verbal memory (p=0.037) and executive function (p=0.043) and a trend of improvement in visual memory (p=0.052) compared to controls.
  
  
  CONCLUSIONS
  EC-IC bypass surgery in carefully selected patients could improve cerebral hemodynamics and verbal memory and executive function.
authors: Department of Pharmacology, National University Health System, Singapore.
authors: Yanhong
authors: Y
authors: Dong
authors: Hock Luen
authors: HL
authors: Teoh
authors: Bernard P L
authors: BP
authors: Chan
authors: Chou
authors: C
authors: Ning
authors: Tseng Tsai
authors: TT
authors: Yeo
authors: Arvind K
authors: AK
authors: Sinha
authors: Narayanaswamy
authors: N
authors: Venketasubramanian
authors: Melissa J
authors: MJ
authors: Slavin
authors: Perminder
authors: P
authors: Sachdev
authors: Simon L
authors: SL
authors: Collinson
authors: Christopher
authors: C
authors: Chen
authors: Vijay K
authors: VK
authors: Sharma
mesh_terms: D000328:Adult; D000368:Aged; D001288:Attention; D016893:Carotid Stenosis / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007802:Language; D007858:Learning; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010865:Pilot Projects; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology*; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial