Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST) Efficacy of carotid endarterectomy for asymptomatic carotid stenosis. The Veterans Affairs Cooperative Study Group.
Without strong evidence of benefit, the use of carotid endarterectomy for prophylaxis against stroke rose dramatically until the mid-1980s, then declined. Our investigation sought to determine whether carotid endarterectomy reduces the risk of stroke among patients with a recent adverse cerebrovascular event and ipsilateral carotid stenosis.
                We conducted a randomized trial at 50 clinical centers throughout the United States and Canada, in patients in two predetermined strata based on the severity of carotid stenosis--30 to 69 percent and 70 to 99 percent. We report here the results in the 659 patients in the latter stratum, who had had a hemispheric or retinal transient ischemic attack or a nondisabling stroke within the 120 days before entry and had stenosis of 70 to 99 percent in the symptomatic carotid artery. All patients received optimal medical care, including antiplatelet therapy. Those assigned to surgical treatment underwent carotid endarterectomy performed by neurosurgeons or vascular surgeons. All patients were examined by neurologists 1, 3, 6, 9, and 12 months after entry and then every 4 months. End points were assessed by blinded, independent case review. No patient was lost to follow-up.
                Life-table estimates of the cumulative risk of any ipsilateral stroke at two years were 26 percent in the 331 medical patients and 9 percent in the 328 surgical patients--an absolute risk reduction (+/- SE) 17 +/- 3.5 percent (P less than 0.001). For a major or fatal ipsilateral stroke, the corresponding estimates were 13.1 percent and 2.5 percent--an absolute risk reduction of 10.6 +/- 2.6 percent (P less than 0.001). Carotid endarterectomy was still found to be beneficial when all strokes and deaths were included in the analysis (P less than 0.001).
                Carotid endarterectomy is highly beneficial to patients with recent hemispheric and retinal transient ischemic attacks or nondisabling strokes and ipsilateral high-grade stenosis (70 to 99 percent) of the internal carotid artery. 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.
                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.
                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.
                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. The efficacy of carotid endarterectomy in patients with asymptomatic carotid stenosis has not been confirmed in randomized clinical trials, despite the widespread use of operative intervention in such patients.
                We conducted a multicenter clinical trial at 11 Veterans Affairs medical centers to determine the effect of carotid endarterectomy on the combined incidence of transient ischemic attack, transient monocular blindness, and stroke. We studied 444 men with asymptomatic carotid stenosis shown arteriographically to reduce the diameter of the arterial lumen by 50 percent or more. The patients were randomly assigned to optimal medical treatment including antiplatelet medication (aspirin) plus carotid endarterectomy (the surgical group; 211 patients) or optimal medical treatment alone (the medical group; 233 patients). All the patients at each center were followed independently by a vascular surgeon and a neurologist for a mean of 47.9 months.
                The combined incidence of ipsilateral neurologic events was 8.0 percent in the surgical group and 20.6 percent in the medical group (P < 0.001), giving a relative risk (for the surgical group vs. the medical group) of 0.38 (95 percent confidence interval, 0.22 to 0.67). The incidence of ipsilateral stroke alone was 4.7 percent in the surgical group and 9.4 percent in the medical group. An analysis of stroke and death combined within the first 30 postoperative days showed no significant differences. Nor were there significant differences between groups in an analysis of all strokes and deaths (surgical, 41.2 percent; medical, 44.2 percent; relative risk, 0.92; 95 percent confidence interval, 0.69 to 1.22). Overall mortality, including postoperative deaths, was primarily due to coronary atherosclerosis.
                Carotid endarterectomy reduced the overall incidence of ipsilateral neurologic events in a selected group of male patients with asymptomatic carotid stenosis. We did not find a significant influence of carotid endarterectomy on the combined incidence of stroke and death, but because of the size of our sample, a modest effect could not be excluded.
Endarterectomy is of some benefit for 50% to 69% symptomatic stenosis and highly beneficial for 70% to 99% stenosis without near-occlusion. Benefit in patients with carotid near-occlusion is marginal in the short-term and uncertain in the long-term. These results are generalisable only to surgically-fit patients operated on by surgeons with low complication rates (less than 7% risk of stroke and death). Benefit from endarterectomy depends not only on the degree of carotid stenosis, but also on several other factors, including the delay to surgery after the presenting event.