Asymptomatic carotid stenosis surgery

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). 

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%... 

Who benefits most from surgery 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... 

Rothwell PM, Goldstein LB. Carotid endarterectomy for asymptomatic carotid stenosis. Asymptomatic Carotid Surgery Trial. Stroke 2004 35 2425—7. 

Hill AB, Obrand D, O Rourke K, Steinmetz OK, Miller N. Hemispheric stroke following cardiac surgery A case-control estimate of the risk resulting from ipsilateral asymptomatic carotid artery stenosis. Ann Vase Surg 2000 14 200-9. 

Due to the very low event rates in patients with asymptomatic lesions of moderate severity (<60% diameter stenosis), it is unknown whether currently available interventional techniques can improve long-term outcomes over those achievable with optimal medical management. Also unresolved are the indications for carotid stenting in asymptomatic individuals with contralateral carotid occlusion (53) and those undergoing major cardiac or vascular surgery (54). 

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