Characteristics of Ischemic Brain Lesions After Stenting or Endarterectomy for Symptomatic Carotid Artery Stenosis

Carotid artery stenting (CAS) has emerged as an alternative to endarterectomy (CEA) for treatment of atherosclerotic stenosis of the internal carotid artery. The International Carotid Stenting Study (ICSS) was a randomized trial comparing CAS with CEA in patients with symptomatic carotid stenosis. An analysis of short-term outcome data in ICSS revealed a significantly increased risk in the incidence of death, stroke, or myocardial infarction within the first 120 days after randomization in the CAS group compared with the CEA group, mainly driven by a higher rate of nondisabling periprocedural stroke in the stenting arm. The ICSS–Magnetic Resonance Imaging (MRI) substudy compared the risk of periprocedural cerebral ischemia on MRI between the 2 groups. We previously reported our initial finding that a proportion of 50% of patients treated with CAS and 17% of those undergoing CEA had ≥1 new ischemic brain lesions on diffusion-weighted imaging (DWI) a median of 1 day after Background and Purpose—In a substudy of the International Carotid Stenting Study (ICSS), more patients had new ischemic brain lesions on diffusion-weighted magnetic resonance imaging (MRI) after stenting (CAS) than after endarterectomy (CEA). In the present analysis, we compared characteristics of diffusion-weighted MRI lesions. Methods—Number, individual and total volumes, and location of new diffusion-weighted MRI lesions were compared in patients with symptomatic carotid stenosis randomized to CAS (n=124) or CEA (n=107) in the ICSS-MRI substudy. Results—CAS patients had higher lesion numbers than CEA patients (1 lesion, 15% vs 8%; 2–5 lesions, 19% vs 5%; >5 lesions, 16% vs 4%). The overall risk ratio for the expected lesion count with CAS versus CEA was 8.8 (95% confidence interval, 4.4–17.5; P<0.0001) and significantly increased among patients with lower blood pressure at randomization, diabetes mellitus, stroke as the qualifying event, left-side stenosis, and if patients were treated at centers routinely using filter-type protection devices during CAS. Individual lesions were smaller in the CAS group than in the CEA group (P<0.0001). Total lesion volume per patient did not differ significantly. Lesions in the CAS group were more likely to occur in cortical areas and subjacent white matter supplied by leptomeningeal arteries than lesions in the CEA group (odds ratio, 4.2; 95% confidence interval, 1.7–10.2; P=0.002). Conclusions—Compared with patients undergoing CEA, patients treated with CAS had higher numbers of periprocedural ischemic brain lesions, and lesions were smaller and more likely to occur in cortical areas and subjacent white matter. These findings may reflect differences in underlying mechanisms of cerebral ischemia. Clinical Trial Registration—URL: http://www.isrctn.org. Unique identifier: ISRCTN25337470. (Stroke. 2013;44:80-86.)