Asymptomatic carotid stenosis

Ellis MR, Franks PJ, Cuming R, Powell JT, Greenhalgh RM. Prevalence, progression and natural history of asymptomatic carotid stenosis is there a place for carotid endarterectomy Eur J Vase Surg 1992 6 172-177. 

How centers and clinicians were selected to participate in trials is seldom reported, but it can also have important implications for external validity. For example, the Asymptomatic Carotid Atherosclerosis Study (ACAS) trial of endarterectomy for asymptomatic carotid stenosis only accepted surgeons with an excellent safety record, rejecting 40% of applicants initially, and subsequently barring from further participation those who had adverse operative outcomes in the trial. The benefit from surgery in the trial was a result in major... 

Acta Neurologica Latin America 1 71-78 Ghambers BR, Norris J (1984). The case against surgery for asymptomatic carotid stenosis. Stroke 15 964-967... 

Women had a lower risk of ipsilateral ischemic stroke on medical treatment and a higher operative risk in comparison with men. For recently symptomatic carotid stenosis, surgery is very clearly beneficial in women with > 70% stenosis, but not in women with 50-69% stenosis (Fig. 27.4). In contrast, surgery reduced the five-year absolute risk of stroke by 8.0% (95% Cl, 3.4-12.5) in men with 50-69% stenosis. This sex difference was statistically significant even when the analysis of the interaction was confined to the 50-69% stenosis group. These same patterns were also shown in both of the large published trials of CEA for asymptomatic carotid stenosis (Rothwell 2004). 

MacKinnon AD, Aaslid R, Markus HS (2005). Ambulatory transcranial Doppler cerebral embolic signal detection in symptomatic and asymptomatic carotid stenosis. Stroke 36 1726-1730... 

When asymptomatic carotid stenosis is discovered, four questions arise. 

The answers to these questions are different for asymptomatic carotid stenosis than for symptomatic stenosis, because the risk of stroke on medical treatment alone is lower distal to an asymptomatic stenosis (Fig. 28.1). 

The more pragmatic Medical Research Council Asymptomatic Carotid Surgery Trial (ACST) has probably produced more widely generalizable results (Halliday et al. 2004). Between 1993 and 2003, ACST randomized 3120 patients with > 60% mainly asymptomatic carotid stenosis (12% had symptoms at least six months previously) to immediate endarterectomy plus medical treatment versus medical treatment alone or until the operation became necessary. Surgeons were required to provide evidence of an operative risk of 6%... 

Risk of carotid endarterectomy for asymptomatic carotid stenosis... 

Fig, 28.3. The effect of endarterectomy for asymptomatic carotid stenosis on the risk of any stroke and operative death by sex (Rothwell 2004) in the /ksymptomatic Carotid Surgery Trial (ACST Halliday ef al. 2004) and the AC/ S Trial (Executive Committee for the Asymptomatic Carotid Atherosclerosis Study 1995). Cl, confidence interval. 

Abbott AL, Chambers BR, Stork JL et al. (2005). Embolic signals and prediction of ipsilateral stroke or transient ischemic attack in asymptomatic carotid stenosis a multicenter prospective cohort study. Stroke 36 1128-1133 Akins CW (1995). The case for concomitant carotid and coronary artery surgery. British Heart Journal 74 97-98... 

Spence JD, Tamayo A, Lownie SP et al. (2005). Absence of microemboli on transcranial Doppler identifies low-risk patients with asymptomatic carotid stenosis. Stroke 36 2373-2378... 

Homocysteine—still under study, but hyperhomocysteinemia may be related to increased stroke risk Asymptomatic carotid stenosis Subclinical disease—aortic arch atheromas Multiple Risk Factors—Stroke Is Increased by the Presence of Multiple Risk Factors Framingham profile... 

There are two ongoing prospective clinical randomized trials of CAS versus CEA in low-surgical risk patients in the United States (ACT 1, CREST). The Asymptomatic Carotid Stenosis Stenting versus Endarterectomy Trial (ACT 1, Abbott Vascular) is in the enrollment phase and it will randomize up to 1658... 

Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. Endarterectomy for asymptomatic carotid stenosis. JAMA 1995 273 1421-8. 

Chambers BR, You RX, Donnan GA. Carotid endarterectomy for asymptomatic carotid stenosis. Cochrane Database Syst Rev 2003 1 1-15. 

Bond R, Rerkasem K, Rothwell PM. High morbidity due to endarterectomy for asymptomatic carotid stenosis. Cerebrovasc Dis 2003 16(Suppl.) 65. 

Nicolaides AN, Kakkos S, Griffin M, et al. Severity of asymptomatic carotid stenosis and risk of ipsilateral hemispheric... 

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