title: Extracranial-intracranial bypass surgery for stroke prevention in hemodynamic cerebral ischemia: the Carotid Occlusion Surgery Study randomized trial.
abstract: BACKGROUND
  Patients with symptomatic atherosclerotic internal carotid artery occlusion (AICAO) and hemodynamic cerebral ischemia are at high risk for subsequent stroke when treated medically.
  
  
  OBJECTIVE
  To test the hypothesis that extracranial-intracranial (EC-IC) bypass surgery, added to best medical therapy, reduces subsequent ipsilateral ischemic stroke in patients with recently symptomatic AICAO and hemodynamic cerebral ischemia.
  
  
  METHODS
  Parallel-group, randomized, open-label, blinded-adjudication clinical treatment trial conducted from 2002 to 2010.
  
  
  METHODS
  Forty-nine clinical centers and 18 positron emission tomography (PET) centers in the United States and Canada. The majority were academic medical centers.
  
  
  METHODS
  Patients with arteriographically confirmed AICAO causing hemispheric symptoms within 120 days and hemodynamic cerebral ischemia identified by ipsilateral increased oxygen extraction fraction measured by PET. Of 195 patients who were randomized, 97 were randomized to receive surgery and 98 to no surgery. Follow-up for the primary end point until occurrence, 2 years, or termination of trial was 99% complete. No participant withdrew because of adverse events.
  
  
  METHODS
  Anastomosis of superficial temporal artery branch to a middle cerebral artery cortical branch for the surgical group. Antithrombotic therapy and risk factor intervention were recommended for all participants.
  
  
  METHODS
  For all participants who were assigned to surgery and received surgery, the combination of (1) all stroke and death from surgery through 30 days after surgery and (2) ipsilateral ischemic stroke within 2 years of randomization. For the nonsurgical group and participants assigned to surgery who did not receive surgery, the combination of (1) all stroke and death from randomization to randomization plus 30 days and (2) ipsilateral ischemic stroke within 2 years of randomization.
  
  
  RESULTS
  The trial was terminated early for futility. Two-year rates for the primary end point were 21.0% (95% CI, 12.8% to 29.2%; 20 events) for the surgical group and 22.7% (95% CI, 13.9% to 31.6%; 20 events) for the nonsurgical group (P = .78, Z test), a difference of 1.7% (95% CI, -10.4% to 13.8%). Thirty-day rates for ipsilateral ischemic stroke were 14.4% (14/97) in the surgical group and 2.0% (2/98) in the nonsurgical group, a difference of 12.4% (95% CI, 4.9% to 19.9%).
  
  
  CONCLUSIONS
  Among participants with recently symptomatic AICAO and hemodynamic cerebral ischemia, EC-IC bypass surgery plus medical therapy compared with medical therapy alone did not reduce the risk of recurrent ipsilateral ischemic stroke at 2 years.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00029146.
authors: Department of Neurology, Box 7025, Room 2131, 170 Manning Dr, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. powersw@neurology.unc.edu
authors: William J
authors: WJ
authors: Powers
authors: William R
authors: WR
authors: Clarke
authors: Robert L
authors: RL
authors: Grubb
authors: Tom O
authors: TO
authors: Videen
authors: Harold P
authors: HP
authors: Adams
authors: Colin P
authors: CP
authors: Derdeyn
mesh_terms: D000368:Aged; D000714:Anastomosis, Surgical; D001921:Brain / Q000098:blood supply; D002545:Brain Ischemia / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000601:surgery*; D002343:Carotid Artery, Internal / Q000473:pathology*; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D057239:Early Termination of Clinical Trials; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000601:surgery*; D049268:Positron-Emission Tomography; D012008:Recurrence; D012039:Regional Blood Flow; D020521:Stroke / Q000209:etiology / Q000517:prevention & control*; D013699:Temporal Arteries / Q000601:surgery*