Abstract
Background
Carotid endarterectomy (CEA) is of proven benefit in recently-symptomatic patients with severe carotid stenosis. Its role in asymptomatic stenosis is still debated. The Asymptomatic Carotid Surgery Trial (ACST) more than doubled the number of patients randomised to CEA trials. This revised review incorporates the recently published ACST results.
Objectives
To determine the effects of CEA for patients with asymptomatic carotid stenosis.
Search methods
We searched the Cochrane Stroke Group Trials Register (searched May 2004), MEDLINE (1966 to May 2004), EMBASE (1980 to June 2004), Current Contents (1995 to January 1997), and reference lists of relevant articles. We contacted researchers in the field to identify additional published and unpublished studies.
Selection criteria
All completed randomised trials comparing CEA to medical treatment in patients with asymptomatic carotid stenosis.
Data collection and analysis
Two reviewers extracted data and assessed trial quality. Attempts were made to contact investigators to obtain missing information.
Main results
Three trials with a total of 5223 patients were included. In these trials, the overall net excess of operation-related perioperative stroke or death was 2.9%. For the primary outcome of perioperative stroke or death or any subsequent stroke, patients undergoing CEA fared better than those treated medically (relative risk (RR) 0.69, 95% confidence interval (CI) 0.57 to 0.83). Similarly, for the outcome of perioperative stroke or death or subsequent ipsilateral stroke, there was benefit for the surgical group (RR 0.71, 95% CI 0.55 to 0.90). For the outcome of any stroke or death, there was a non-significant trend towards fewer events in the surgical group (RR 0.92, 95% CI 0.83 to 1.02). Subgroup analyses were performed for the outcome of perioperative stroke or death or subsequent carotid stroke. CEA appeared more beneficial in men than in women and more beneficial in younger patients than in older patients although the data for age effect were inconclusive. There was no statistically significant difference between the treatment effect estimates in patients with different grades of stenosis but the data were insufficient.
Authors’ conclusions
Despite about a 3% perioperative stroke or death rate, CEA for asymptomatic carotid stenosis reduces the risk of ipsilateral stroke, and any stroke, by approximately 30% over three years. However, the absolute risk reduction is small (approximately 1% per annum over the first few years of follow up in the two largest and most recent trials) but it could be higher with longer follow up.
Plain language summary
Carotid endarterectomy for asymptomatic carotid stenosis
For most people with a narrowing of the carotid artery which is not causing symptoms a surgical operation to remove the narrowing carries a risk and has little benefit. Carotid stenosis is a narrowing of a major artery in the neck taking blood to the brain. This can cause a stroke. If the narrowing is severe and has caused symptoms, surgery to remove the narrowing (carotid endarterectomy) reduces the risk of stroke. However, if the narrowing has not caused any symptoms the risk of stroke is not very high. Although this low risk can be lowered further by surgery, the surgery itself can sometimes cause a stroke or death. The overall effect of surgery is a small benefit.
