Addendum

Since the presentation of this material at the 18th meeting of the Canadian Society for Vascular Surgery in September 1996, there have been new developments in the indications for carotid endarterectomy for preventing stroke.

The North American Symptomatic Carotid Endarterectomy Trial (NASCET), a 12-year study sponsored by the National Institute of Neurological Disorders and Stroke, examined the benefit of carotid endarterectomy for patients with symptoms of stroke associated with 30% to 39% carotid artery stenosis. In 1991, early data were released regarding the benefit of surgery for patients with 70% to 99% carotid artery stenosis in the prevention of stroke. Since then the study has focussed on carotid endarterectomy for symptomatic patients with moderate (30% to 69% carotid artery stenosis). The results of the final phase of the NASCET were announced at the American Heart Association's 23rd International Joint Conference on Stroke and Cerebral Circulation in February 1998. The results demonstrated that patients with carotid artery stenosis greater than 50% clearly benefit from surgery.