Commentary

Carotid endarterectomy

Class III: No Benefit Except in extraordinary circumstances, carotid revascularization by either CEA or CAS is not recommended when atherosclerosis narrows the lumen by less than 50% (35,70,74,369,377). ( Level of Evidence: A)

In the subgroup with severe large-artery stenosis or occlusion (259 patients), including ECVD, there was no benefit of warfarin over aspirin after 2 years, but patients with carotid stenosis sufficiently severe to warrant surgical intervention were excluded. The combination of clopidogrel and aspirin did not reduce stroke risk compared with either treatment alone in the MATCH (Management of Atherothrombosis with Clopidogrel in High-Risk Patients) and CHARISMA (Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance) trials (27,61); however, in ESPS-2 (Second European Stroke Prevention Study), the combination of aspirin plus dipyridamole was superior to aspirin alone in patients with prior TIA or stroke (28). Outcomes in a subgroup defined on the basis of ECVD were not reported.

Second, adverse events were more frequent in randomized controlled trials compared to observational studies. This could be because the effects of patient and surgeon selection [33] in randomized trials are offset by generally better adverse event assessment, or because observational studies are more likely than randomized controlled trials to go unpublished if study findings are unfavorable. Among observational studies, higher quality ratings predicted higher rates of adverse events—a factor that should be taken into account when comparing the results of randomized controlled trials and observational studies [34–37].