Editorial The Extracranial- Intracranial Bypass Study

In a recent editorial (1) it was argued that though there is good evidence that most transient ichaemic attacks and strokes in the carotid territory are due to thrombo-embolism, there is as yet no scientific proof that carotid endarterectomy prevents more strokes than it causes. The European Carotid Surgery trial is currently addressing this particular point in a multicentre randomised study. The other surgical procedure introduced for the prevention of stroke is the extracranial-intracranial bypass graft (2). An anastomosis is made through a burr hole or small trephine beween a scalp vessel such as the superficial temporal artery, and a cortical branch of the middle cerebral artery. With an operating microscope, and microsurgical techniques, vessels of 1 to 2 mm can be anastomosed, and patency rates of 90 per cent are readily achieved. This procedure was perceived as being appropriate for patients in whom haemodynamic factors probably predominated in their stroke risk, for example patients with stenosis of a middle cerebral artery with little collateral protection, or with occlusion of the carotid artery. To the great credit of the vascular and neurosurgeons they have been prepared to put this popular procedure to the test, and the results of the recently completed randomised trial mak