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Ischemic Stroke—Stenting versus Surgery for Carotid Disease


medical treatment (ARR 6.5 %, NNT 15.4, p=0.045). Finally, with <50 % symptomatic stenosis, there was no significant difference, with a five-year rate of ipsilateral stroke of 14.9 % in the CEA group and 18.7 % in the medical therapy group (p=0.16).4,6


Subset analysis found that patients who


were aged 75 and older benefited more from CEA than younger patients.11 Post hoc analyses further revealed gender differences in the 50–69 % group, with a statistical benefit from CEA seen only in men but not in women.


ECST initially used a different approach from NASCET to the measurement of the degree of carotid stenosis but they subsequently re-analyzed the angiography data to be consistent with NASCET (see Figure 1 for NASCET criteria). Surgery reduced the five-year risk of any stroke or surgical death by 5.7 % (95 % confidence interval [CI] 0–11.6) in patients with 50–69 % stenosis by NASCET criteria (n=646, p=0.05) and by 21.2 % (95 % CI 12.9–29.4) in patients with 70–99 % stenosis by NASCET criteria without ‘near-occlusion’ (n=429, p<0.0001). Thus results of the ECST and NASCET were very consistent.12


Pooled Analysis and Subset Analysis of Carotid Endarterectomy Trials


Analysis of the pooled data from the NASCET, ECST, and the Veterans Affair 309 study (a smaller randomized trial involving 189 patients with symptomatic carotid stenosis) confirmed the efficacy of CEA in patients with symptomatic carotid disease.13


The analysis showed that surgery


increased the five-year risk of ipsilateral ischemic stroke in patients with less than 30 % carotid stenosis, had no effect in patients with 30–49 % carotid stenosis, and was of marginal benefit in those with 50–69 % carotid stenosis. However, surgery was highly beneficial in patients with ≥70 % carotid stenosis but not near-occlusion. Importantly, surgical morbidity and mortality exceeding 6 % in symptomatic stenosis could negate the benefit gained from CEA.14,15


The combined data allowed for more precise subgroup analyses. For timing of the procedure, it was seen that CEA was most beneficial if carried out within the first two weeks after a non-disabling stroke or TIA.16


The diameter of the artery in the projection that displays the greatest degree of stenosis (S) and at a normal segment distal to the stenosis (N). The percentage of stenosis = (1-S/N) x 100. CCA = common carotid artery; ECA = external carotid artery; ICA = internal carotid artery.


artery, and it is unknown whether patients with ipsilateral stroke with disabling deficits or severe comorbidities due to a medical or surgical condition would benefit or not.20


Carotid Angioplasty and Stenting in Symptomatic Carotid Disease


CEA is also likely to be beneficial for patients who have symptomatic ipsilateral carotid stenosis and co-existing severe contralateral carotid stenosis or occlusion, in spite of the increased risk compared with medical treatment alone.18


The interactions between all


of these factors are complicated, but it is worth noting that time to CEA has the greatest impact on the potential benefit for women, such that it is reasonable to consider revascularizing women with 50–69 % stenosis, if this is carried out within two weeks of the first ischemic event.19


There was no clear benefit of the procedure in patients with total or near-total occlusion of the symptomatic ipsilateral internal carotid


US NEUROLOGY


In general, men benefit from CEA more than women with symptomatic carotid stenosis revascularization; however, CEA is clearly beneficial for women with 70–99 % symptomatic carotid stenosis.17 Some symptomatic subgroups appeared to derive more benefit from CEA and these include patients aged 75 years or more, patients with ulcerated plaques, and patients with recent TIAs within two weeks of randomization.16


Based upon the previously discussed studies, CEA is considered the gold standard therapy for patients with symptomatic severe carotid stenosis. CAS is an attractive alternative as it is less invasive and associated with less cranial nerve injury and fewer bleeding complications. Within the past five years, considerable high-level data have become available as multiple randomized studies that have compared CAS to CEA have been completed.


The Stent-protected angioplasty versus carotid endarterectomy (SPACE) trial was an international, multicenter, randomized controlled European study designed to test the non-inferiority of CAS to CEA for the treatment of severe symptomatic carotid stenosis. One thousand two hundred patients with symptomatic carotid artery stenosis were randomly assigned within 180 days of TIA or moderate stroke (modified Rankin scale score of ≤3) to carotid artery stenting (n=605) or CEA (n=595).21


The primary


endpoint (rate of ipsilateral ischemic stroke or death occurring within 30 days of the procedure) was 6.8 % in CAS and 6.3 % in CEA (absolute difference of 0.51 %, 90 % CI -1.89–2.91), which was greater than the


121


ECST was a multicenter randomized controlled trial that enrolled 3,024 patients who had at least one transient or mild symptomatic ischemic vascular event within the previous six months due to ipsilateral carotid artery stenosis.5


Figure 1: Measurement of an Internal Carotid Artery Stenosis Using the North American Symptomatic Carotid Endarterectomy Trial Criteria


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