Identifying Asymptomatic Carotid Stenosis Patients at High Risk of Cerebrovascular Events

Pecoraro et al in this issue of Angiology evaluate the use of cerebral computed tomography (CT) scans as a tool to identify patients with asymptomatic internal carotid artery stenosis at high risk of ischemic cerebrovascular events. Thalamic or cortical/subcortical infarctions in or near the anterior/middle cerebral artery territory or basal ganglia were demonstrated by CT in 60% versus 20% for symptomatic and asymptomatic patients, respectively. In addition, symptomatic patients had a higher incidence of ‘‘vulnerable’’ carotid plaques (odds ratio: 4.49; 95% confidence interval: 1.2116.60; P 1⁄4 .01). The authors postulated that the combination of a complex atherosclerotic carotid plaque with positive cerebral CT findings could be used to identify a subgroup of asymptomatic patients who will benefit from carotid revascularization. This editorial discusses some issues regarding the management of patients with asymptomatic carotid artery stenosis. The optimal management of carotid artery stenosis is still extensively debated. Patients with symptomatic carotid stenosis are at high risk of recurrent ischemic cerebrovascular events; thus, a carotid intervention is warranted. At present, carotid endarterectomy (CEA) is associated with superior outcomes compared with carotid artery stenting (CAS) in these patients. In the absence of contraindications (eg, distal internal carotid artery lesion, scarred neck, etc), CEA should be the treatment of choice in these individuals. The results of CAS and CEA in patients with asymptomatic carotid stenosis are comparable. Nevertheless, the necessity for any intervention (ie, CAS or CEA) in most asymptomatic patients has been questioned and the management of the majority of these patients with best medical treatment (BMT) alone has been proposed. Reliable predictors that can identify those asymptomatic patients at high risk of cerebrovascular events could make it possible to select those who are most likely to benefit from CAS/CEA. Several attempts have been made to identify predictors of future cerebrovascular events in asymptomatic individuals. Examples include the presence of microemboli on transcranial Doppler, silent embolic infarcts on brain CT scans, the combination of clinical and ultrasonic plaque characteristics (severe carotid artery stenosis, history of contralateral cerebrovascular event, low grayscale median, increased plaque area, plaque types 1, 2, and 3, and the presence of discrete white areas without acoustic shadowing), the presence of carotid plaque ulceration on 3-dimensional ultrasound, or a combination of ultrasonic plaque echolucency and microemboli on transcranial Doppler. It is hoped that these (and perhaps other) predictors may identify the high-risk asymptomatic individuals where BMT alone may not be sufficient. Smoking cessation, adopting a healthier lifestyle, control of diabetes mellitus, and hypertension as well as routine administration of antiplatelet agents and statins are essential components of BMT for these patients. Statins, in particular, are associated with several beneficial effects in carotid patients (eg, reduction of both carotid intima–media thickness progression and cerebrovascular events). Statins are also associated with improved outcomes when patients undergo CAS or CEA. The most recent guidelines by the American as well as the European Society for Vascular Surgery recommend routine use of statin for all patients with carotid stenosis. Aggressive statin treatment is associated with more beneficial effects compared with moderate lipid-lowering therapy. The effects of aggressive BMT on carotid atherosclerosis were demonstrated in a report from Canada. This study compared the association between BMT with the occurrence of microemboli on transcranial Doppler before and after 2003 in patients with asymptomatic carotid stenosis. By 2003, a policy of intensive atherosclerosis management was introduced for these patients, including among others statin treatment at the maximal tolerated