Endarterectomy was not effective for moderate symptomatic carotid stenosis
ACP J Club. 1996 Sept-Oct;125:29. doi:10.7326/ACPJC-1996-125-2-029
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European Carotid Surgery Trialists' Collaborative Group. Endarterectomy for moderate symptomatic carotid stenosis: interim results from the MRC European Carotid Surgery Trial. Lancet. 1996 Jun 8;347:1591-3. [PubMed ID: 8667868]
To determine the effect of endarterectomy in patients with recent cerebrovascular events who have moderate atherosclerotic internal carotid artery stenosis.
Randomized controlled trial with mean follow-up of 3.9 to 4.5 years (European Carotid Surgery Trial [ECST]).
97 hospitals in 15 European countries.
1590 patients (mean age 63 y, 73% men) who had had a nondisabling, carotid-territory, ischemic stroke or transient ischemic attack, or retinal infarction in the previous 6 months for whom the neurologist and surgeon were uncertain whether to recommend carotid endarterectomy for the symptomatic artery. Patients had moderate carotid stenosis between 30% and 69% according to ECST measurement methods, which translates to < 50% stenosis according to North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurement methods. All patients completed at least 4 months of follow-up.
959 patients were allocated to carotid endarterectomy, and 631 patients were allocated to no surgery.
Main outcome measures
Primary outcomes were survival and survival that was free of any new, major stroke (i.e., longer than 7 d).
Analysis was by intention to treat. Surgery did not lead to a difference in all-cause mortality. For patients with 30% to 49% stenosis allocated to surgery (n = 648), the estimated hazard ratio (HR) for death was 1.29, 95% CI 0.88 to 1.90, and for patients with 50% to 69% stenosis (n = 942), the HR was 1.18, CI 0.88 to 1.58. Between 0 and 3.4 years of follow-up, patients with 30% to 49% stenosis who had surgery had more occurrences of major stroke or death than did patients who did not have surgery (P < 0.05). In patients with 50% to 69% stenosis, the risk associated with surgery lasted for up to 2.3 years (P < 0.05). After these times, the groups did not differ for stroke-free survival.
Endarterectomy conferred no benefit on patients who had recent cerebrovascular events and moderate-grade internal carotid artery stenosis at 4.5 years of follow-up.
Sources of funding: Medical Research Council (UK) and European Union (Biomed 1).
For article reprint: Mr. J. Slattery, Department of Clinical Neurosciences, Western General Hospital, Edinburgh EH4 2XU, Scotland, UK. FAX 44-34-32-620.
The ECST (1) and NASCET (2) have clearly shown that patients with recent focal cerebral ischemic symptoms and high-grade carotid stenosis received benefit from carotid endarterectomy. It is important to note that the methods for measuring carotid stenosis were different in the 2 trials. Using the measurement method of NASCET, the first ECST report included symptomatic patients with stenosis ranging from 50% to 99%, and this broader range of severity in ECST may account for the lesser benefit seen for this group of patients in the initial reports from these trials. Barnett and Warlow showed that the results for the 2 trials of carotid endarterectomy and severe stenosis were similar if an adjustment was made for the differing methods of measurement (3).
In the report from ECST, it is now seen that symptomatic patients with moderate stenosis did not benefit from carotid endarterectomy. The lack of benefit was shown for patients with as much as 69% stenosis by ECST measurements, which by the measurement standards of NASCET would include patients with as much as 50% stenosis.
The NASCET study, completed in 1999, shows that carotid endarterectomy modestly reduced the risk for ipsilateal stroke, any stroke, and all-cause mortality combined with either any stroke or disabling stroke when the initial symptomatic stenosis was 50% to 69%, but not when the stenosis was <50% (4).
NASCET showed increasing benefits for grades of stenosis between 70% and 99% stenosis. The lines that have been drawn for mild, moderate, and severe stenosis are arbitrary. It is necessary to analyze the data with different definitions for moderate and severe stenosis. Even at higher degrees of stenosis, however, benefit from carotid endarterectomy is likely lost when surgical mortality and stroke morbidity is over 10%.
Jack P. Whisnant, MD
Mayo ClinicRochester, Minnesota, USA
1. European Carotid Surgery Trialists' Collaborative Group. MRC European Carotid Surgery Trial: interim results for symptomatic patients with severe (70-99%) or with mild (0-29%) carotid stenosis. European Carotid Surgery Trialists' Collaborative Group. Lancet. 1991;337:1235-43.
2. North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1991;325:445-53.
4. Barnett HJ, Taylor DW, Eliasziw M, et al., for the North American Symptomatic Carotid Endarterectomy Trial Collaborators. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. N Engl J Med. 1998;339:1415-25.