The extracranial-intracranial (EC-IC) bypass surgery has been widely used in the treatment of cerebral ischemia,intracranial aneurysms,and other diseases for more than 40 years.In terms of treating atherosclerotic cerebral ischemia,the surgery is presumed to be helpful for the subgroup of hemodynamic compromise in prevention of subsequent stroke.However,two multicenter trials presented with high perioperative stroke rate and failed to demonstrate the profit of the surgery.1-3 On this point,one of the crucial issues currently is how to lower down the perioperative stroke rate,the centerpiece of which is early postoperative infarction (EPI).3