Extracranial Thrombotically Active Carotid Plaque as a Risk Factor for Ischemic Stroke

Abstract

Patients with substantial carotid artery narrowing are at increased risk for major stroke,^1-6 but the pathogenic mechanisms linking carotid atherosclerosis and ischemic brain injury still need to be fully clarified.Clinical trials designed to evaluate the beneficial effects of endarterectomy in symptomatic and asymptomatic patients have focused on carotid stenosis severity and plaque ulceration as risk factors for cerebrovascular events. The results of the European Carotid Surgery Trial^2,3 and the North American Symptomatic Carotid Endarterectomy Trial(NASCET)^4,5 suggest that surgery is indicated for stroke prevention when stenosis is more than 70%. TheNASCET study showed that among symptomatic patients with high-grade carotid stenosis (>70%) not treated by surgery, the 2-year rate of any ipsilateral stroke was 26.0% for major stroke and 13.1% for fatal stroke.⁵ The Asymptomatic Carotid Atherosclerosis Study⁷ suggested that indications for carotid endarterectomy could be broadened to include asymptomatic patients with carotid stenosis of more than 60% and that the aggregate risk over 5 years for ipsilateral stroke and any perioperative stroke was estimated at 11.0% for asymptomatic patients treated medically.