Roles of Extracranial/Intracranial Arterial Bypass Surgery in Treatments of Occlusive Cerebrovascular Disease

Abstract

To clarify the efficacy of extracranial/intracranial arterial bypass (EC/IC bypass) surgery in treatment of patients with occlusive cerebrovascular disease, we retrospectively analyzed the clinical and hemodynamic results in the patients who underwent EC/IC bypass surgery in our institute. In the last 7 years, we have carried out EC/IC bypass surgery in 75 patients with occlusive cerebrovascular disease. In these patients, we analyzed the following points: 1) correlation between preoperative angiographic/hemodynamic status and postoperative improvements of hemodynamic status, 2) correlation between postoperative improvements of hemodynamic status and neurological function after surgery, and 3) correlation between postoperative improvements of hemodynamic status and ischemic episodes after surgery. Postoperative improvements of hemodynamic status were achieved in patients who had both spontaneously developed leptomeningeal anastomosis and decreased reactivity of cerebral blood flow to acetazolamide before surgery. Obvious improvements of neurological function were noted soon after surgery in 11 patients. All of these 11 patients showed marked improvements of hemodynamic status. After surgery, 64 patients did not have any ischemic episodes, but 8 experienced transient ischemic attacks and 3 suffered from cerebral embolic infarctions. Of these 11 patients with postoperative ischemic episodes, 10 had improvements of hemodynamic status. EC/IC bypass surgery can improve hemodynamic status in patients with obviously impaired hemodynamic reserve and has a potential to improve neurological functions impaired by hemodynamic insufficiency. However, there were no correlation between improvements of hemodynamic status and occurrence of ischemic episodes. Even in the patients with hemodynamic insufficiency, the major mechanism of ischemia may be embolic.