Extracranial-Intracranial Bypass Surgery for Stroke Prevention in Hemodynamic Cerebral Ischemia: The Carotid Occlusion Surgery Study: A Randomized Trial

By W. Powers, W. Clarke, R. Grubb, T. Videen, H. Adams, C. Derdeyn. Journal of the American Medical Association (JAMA), 2011

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Context Patients with symptomatic atherosclerotic internal carotid artery occlusion (AICAO) and hemodynamic cerebral ischemia are at high risk for subsequent stroke when treated medically. Objective 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. Design Parallel group, randomized, open-label, blinded-adjudication clinical treatment trial conducted from 2002–2010. Setting 49 clinical centers and 18 positron emission tomography (PET) centers in the United States and Canada. The majority were academic medical centers. Participants Arteriographically-confirmed AICAO causing hemispheric symptoms within 120 days and hemodynamic cerebral ischemia identified by ipsilateral increased oxygen extraction fraction measured by PET. 195 were randomized: 97 to surgery and 98 to no surgery. Follow-up for the primary endpoint until occurrence, 2 years, or end of trial was 99% complete. No participant withdrew because of adverse events. Interventions Anastomosis of superficial temporal artery branch to a middle cerebral artery cortical branch for the surgical group. Anti-thrombotic therapy and risk factor intervention were recommended for all. Main Outcome Measure For all participants who were assigned to surgery and received surgery, the combination of (1) all stroke and death from surgery through 30 days post 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 was the combination of (1) all stroke and death from randomization to randomization plus 30 days and (2) ipsilateral ischemic stroke within two years of randomization. Results The trial was terminated early for futility. Two-year rates for the primary endpoint 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=0.78, z-test); difference = 1.7% (95% CI, −10.4% to 13.8%). Thirty-day rates for ipsilateral ischemic stroke were 14.3% (14/97) in the surgical group and 2.0% (2/98) in the nonsurgical group; difference = (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 to medical therapy alone did not reduce the risk of recurrent ipsilateral ischemic stroke at 2 years.

Subfields: Epidemiology, Pulmonary and Respiratory Medicine, Rheumatology

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