OBJECTIVE: The purpose of this study was to evaluate cognitive functions in patients undergoing extracranial-intracranial (EC-IC) bypass surgery for cerebral ischemia. POPULATION AND METHODS: From August 2003 to January 2009, 276 patients with occluded internal carotid arteries (ICA) were screened. Forty of these met the criteria for a low-flow EC-IC bypass. These patients were identified based on evidence of exhausted vasomotor reactivity (VMR) using the Doppler CO(2) test and CT perfusion. These patients were invited to have a complete battery of neuropsychological tests preoperatively and 12 months after surgery. Complete neurocognitive testing was finished in 20 patients. RESULTS: This group of 20 patients showed preoperative cognitive impairment ranging from mild to medium-severe. There were no cases of stroke ipsilateral to the operated side during the follow-up period. VMR improvement was seen in all patients within 6 months of surgery. A comparison using a paired t-test demonstrated significant improvement 12 months after surgery in the following neuropsychological tests: WAIS-R (p = 0.01), Number Collection Test (p = 0.02), Trail Making Test (p = 0.03), and Benton Visual Retention Test (p = 0.05). Repeat analysis of variance (ANOVA) suggested the following predictors associated with cognitive improvement:the presence of ophthalmic collateral flow (p = 0.04), preoperative amaurosis fugax (p = 0.02), and external watershed infarction detected by MRI (p = 0.04). CONCLUSION: Patients with occlusion of the ICA and exhausted VMR have cognitive impairment prior to EC-IC bypass surgery. Twelve months after surgery, there is significant improvement in various areas of cognition.

Department of Neurosurgery České Budějovice Hospital B Němcové 54 370 87 České Budějovice Czech republic

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