Does carotid endarterectomy reduce the risk of stroke in patients with symptomatic moderate or severe carotid stenosis?
Carotid endarterectomy provides durable stroke risk reduction in symptomatic patients with severe (≥70%) stenosis and moderate benefit in those with 50-69% stenosis, but no benefit for <50% stenosis.
Endarterectomy in patients with symptomatic moderate carotid stenosis of 50 to 69 percent yielded only a moderate reduction in the risk of stroke. Decisions about treatment for patients in this category must take into account recognized risk factors, and exceptional surgical skill is obligatory if carotid endarterectomy is to be performed. Patients with stenosis of less than 50 percent did not benefit from surgery. Patients with severe stenosis (> or =70 percent) had a durable benefit from endarterectomy at eight years of follow-up.
Barnett et al. (1998) studied this question.