Elsevier

The Lancet

Volume 351, Issue 9113, 9 May 1998, Pages 1379-1387
The Lancet

Articles
Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST)*

https://doi.org/10.1016/S0140-6736(97)09292-1Get rights and content

Summary

Background

Our objective was to assess the risks and benefits of carotid endarterectomy, primarily in terms of stroke prevention, in patients with recently symptomatic carotid stenosis.

Methods

This multicentre, randomised controlled trial enrolled 3024 patients. We enrolled men and women of any age, with some degree of carotid stenosis, who within the previous 6 months had had at least one transient or mild symptomatic ischaemic vascular event in the distribution of one or both carotid arteries. Between 1981 and 1994, we allocated 1811 (60%) patients to surgery and 1213 (40%) to control (surgery to be avoided for as long as possible). Follow-up was until the end of 1995 (mean 6·1 years), and the main analyses were by intention to treat.

Findings

The overall outcome (major stroke or death) occurred in 669 (37·0%) surgery-group patients and 442 (36·5%) control-group patients. The risk of major stroke or death complicating surgery (7·0%) did not vary substantially with severity of stenosis. On the other hand, the risk of major ischaemic stroke ipsilateral to the unoperated symptomatic carotid artery increased with severity of stenosis, particularly above about 70–80% of the original luminal diameter, but only for 2–3 years after randomisation. On average, the immediate risk of surgery was worth trading off against the long-term risk of stroke without surgery when the stenosis was greater than about 80% diameter; the Kaplan-Meier estimate of the frequency of a major stroke or death at 3 years was 26·5% for the control group and 14·9% for the surgery group, an absolute benefit from surgery of 11·6%. However, consideration of variations in risk with age and sex modified this simple rule based on stenosis severity. We present a graphical procedure that should improve the selection of patients for surgery.

Interpretation

Carotid endarterectomy is indicated for most patients with a recent non-disabling carotid-territory ischaemic event when the symptomatic stenosis is greater than about 80%. Age and sex should also be taken into account in decisions on whether to operate.

Introduction

We designed the European Carotid Surgery Trial (ECST) as a randomised comparison of “carotid endarterectomy as soon as possible” with “avoid surgery if at all possible, for as long as possible” (ie, surgery versus control) in patients with one or more carotidterritory ischaemic episodes within the previous 6 months and with some degree of stenosis near the origin of the symptomatic internal carotid artery (ICA). From the outset we expected that the balance of surgical risk and benefit, in terms of the prevention of stroke, would vary among categories of patients, and in particular with severity of stenosis. This expectation was borne out by the interim results.1, 2 Now that trial recruitment and follow-up are complete, we can report in detail on the balance of surgical risk and benefit.

Section snippets

Methods

We carried out the trial in 97 centres in 12 European countries and one centre in Australia and described much of the methodology in our first report.1 Ethical approval was obtained in all centres. Informed consent was obtained from each patient in accordance with the requirements of the local ethics committee.

Results

3024 patients received randomised treatment allocation— 1811 surgery and 1213 control (figure 1). The mean follow-up was 6·1 years (mean 6·1 years in the control group, 6·0 years in the surgery group; maximum 13·8 years). We lost only 25 patients (0·83%) to follow-up, six because of emigration. Because 19 of these 25 had at least some follow-up (mean 3·0 years for controls; 3·2 years for surgery group) we were able to include them in the analysis up until the time we lost them. Therefore, 3018

Discussion

The ECST has shown that for patients with recently symptomatic carotid stenosis, carotid endarterectomy carries a small but serious risk of stroke or death; that without surgery there is a substantial risk of stroke ipsilateral to a severely stenosed carotid artery, particularly in the first 2–3 years; and that most of the risk of ipsilateral stroke is abolished by successful surgery, so most of these strokes must be caused by embolism from, or low flow distal to, severe carotid stenosis. These

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*

Writing committee, study organisation, and participants given at end of paper

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