ABSTRACT
The efficacy of EC/IC bypass surgery for the prevention of recurrent ischemic stroke was evaluated in the International EC/IC Bypass Study. In this international randomized trial, patients with symptomatic ICA occlusion or intracranial ICA stenosis, or MCA stenosis or occlusion were treated either with an anastomosis between the superficial temporal artery (STA) and a cortical branch of the middle cerebral artery (MCA) in addition to best medical therapy or with best medical treatment alone (7). In 1985, after randomization of 1377 patients (960 patients with a symptomatic ICA occlusion and 417 with an intracranial ICA stenosis or MCA stenosis or occlusion) over a period of 8 years, the study showed that the operation was not effective, despite good operative results (8). Moreover, subgroup analysis failed to show any trends toward a benefit of the operation in any of the pre-specified subgroups, such as patients with ongoing symptoms after demonstration of the occlusion of the ICA, or patients with frequent transient ischemic attacks (6) and poor collateral blood supply (8,9). As a result, the operation has been largely abandoned throughout the world (10). Proponents of the hemodynamic theory, however, commented that the EC/IC Bypass Study did not restrict the inclusion of patients to those who were at high risk of recurrent stroke, i.e., in whom a compromised blood flow to the hemisphere ipsilateral to the occluded carotid artery had been demonstrated (11-15). If such patients at high risk can indeed be identified, the role of the EC/IC bypass operation needs reappraisal.
