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Does surgery have a role in the management of asymptomatic carotid artery stenosis? Yes, but...

Nature Clinical Practice Neurology volume 4, pages 2–3 (2008)Cite this article

High-grade internal carotid artery stenosis (CAS) is a relatively common condition, occurring in 5–10% of the general population over the age of 65 years. The prevalence of asymptomatic CAS is increased in individuals with vascular risk factors and in those with other manifestations of atherosclerosis such as peripheral artery disease. Only a small fraction of patients with CAS will develop a cerebral or retinal vascular event ipsilateral to this stenosis. In a recent study in patients with asymptomatic CAS who had diabetes or clinical manifestations of arterial disease, the rate of ipsilateral stroke was less than 1% per year.1 According to another study, the rate of ipsilateral stroke in individuals with asymptomatic CAS remained this low over extended periods of follow-up (up to 15 years).2 Surprisingly, CAS seems to be a predictor of vascular death and coronary events, rather than of stroke. Once a transient ischemic attack or amaurosis fugax has occurred, there is little doubt that carotid endarterectomy (CEA) is required, especially if the stenosis is tight and symptoms have occurred recently, because the risk of recurrent ipsilateral stroke is high.3 Few treatments in preventive vascular medicine, however, generate as much controversy as does CEA performed in patients with CAS who do not have any related symptoms, even though large clinical trials have been performed in this setting. The discussion centers mainly around two issues: the clinical relevance of statistically significant results from clinical trials; and the applicability of the trial results to clinical practice. Most guidelines advocate cautious use of CEA for asymptomatic stenosis. Despite these controversies and prudent guidelines, rates of CEA are soaring, at least in some countries.

A recent Cochrane Review summarized the outcomes of CEA for asymptomatic CAS.4 Three trials were performed that collectively randomized 5,223 patients with a total follow-up period of 17,037 years. These trials demonstrated a significant benefit of CEA in reducing the risk of ipsilateral stroke or any subsequent stroke. The operation lowered the risk of an individual meeting the composite end point of perioperative stroke or death or subsequent ipsilateral stroke by 29% (relative risk 0.71, 95% CI 0.55–0.90). The absolute risk reduction was 3.0% over 2.7 years in the Asymptomatic Carotid Atherosclerosis Study (ACAS) and 3.1% over 3.4 years in the Asymptomatic Carotid Surgery Trial (ACST).5,6 On the basis of these figures, about 100 patients would need to undergo the operation to prevent 5 strokes over 5 years, raising doubts about the cost-effectiveness of this procedure. Moreover, the small benefits of surgery are not distributed evenly over the entire group of patients with CAS. In women, evidence is not in favor of the operation. In ACAS, women had a 9% increase in the risk of perioperative stroke, death or subsequent ipsilateral stroke.5 In ACST, the same risk was reduced by 10%.6 Combining data from these clinical trials yields a small, nonsignificant benefit of a 4% relative risk reduction, suggesting no benefit of CEA for women.4 This gender difference might be a statistical artifact resulting from the relatively low proportion of women included in the trials. Other reasons for a reduced benefit might be the higher operative risk and the generally lower recurrent stroke risk in women as compared with men. Longer-term follow-up might clarify the uncertain benefits of surgical treatment in women. Doubt is also raised over the efficacy of the procedure in elderly patients. ACAS did not demonstrate an increased risk of stroke with surgery in patients older than 68 years,5 but in ACST no surgical benefit was observed in patients aged over 75 years.6 The 10-year results from ACST will help to identify whether the risk reduction with CEA persists over time, and whether benefits in women and the elderly might emerge at a later time after surgery.

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References

  1. Goessens BM et al. (2007) Asymptomatic carotid artery stenosis and the risk of new vascular events in patients with manifest arterial disease: the SMART study. Stroke 38: 1470–1475

    Article  Google Scholar 

  2. Nadareishvili ZG et al. (2002) Long-term risk of stroke and other vascular events in patients with asymptomatic carotid artery stenosis. Arch Neurol 59: 1162–1166

    Article  Google Scholar 

  3. Rothwell PM et al. (2003) Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis. Lancet 361: 107–116

    Article  CAS  Google Scholar 

  4. Chambers BR and Donnan GA. Carotid endarterectomy for asymptomatic carotid stenosis. Cochrane Database of Systematic Reviews 2005, Issue 4. Art. No.: CD001923.pub2. 10.1002/14651858.CD001923.pub2

    Google Scholar 

  5. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study (1995) Endarterectomy for asymptomatic carotid artery stenosis. JAMA 273: 1421–1428

  6. Halliday A et al. (2004) Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet 363: 1491–502

    Article  CAS  Google Scholar 

  7. Rothwell PM (2005) External validity of randomised controlled trials: “to whom do the results of this trial apply?” Lancet 365: 82–93

    Article  Google Scholar 

  8. Sillesen H et al. (2007) Atorvastatin treatment in patients with carotid stenosis is associated with a marked reduction in the risk of stroke, cardiovascular events and carotid revascularisation procedures: a substudy of the Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial. Cerebrovasc Dis 23 (Suppl 2): 55

    Google Scholar 

  9. Mas JL et al. (2006) Endarterectomy versus stenting in patients with symptomatic severe carotid stenosis. N Engl J Med 355: 1660–1671

    Article  CAS  Google Scholar 

  10. Dente K (2006) Experts divided over carotid stenting for stroke prevention. Lancet Neurol 5: 24

    Article  Google Scholar 

  11. Chaturvedi S et al. (2005) Carotid endarterectomy—an evidence-based review: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 65: 794–801

    Article  CAS  Google Scholar 

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  1. Dienst Neurologie, UZ Leuven, Herestraat 49, B-3000 Leuven, Belgium vincent.thijs@uzleuven.be

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  1. V Thijs is a Staff Neurologist and Head of the Stroke Program at the University Hospitals in Leuven, Belgium.,

    Vincent Thijs

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The author has received speaker honoraria and grant or research support from Boehringer Ingelheim and Pfizer.

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Thijs, V. Does surgery have a role in the management of asymptomatic carotid artery stenosis? Yes, but.... Nat Rev Neurol 4, 2–3 (2008). https://doi.org/10.1038/ncpneuro0681

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