4. Cerebral embolism in endarterectomy versus stenting for symptomatic carotid artery stenosis: The significance of plaque morphology on duplex ultrasound

Abstract

Carotid stenting (CAS) and carotid endarterectomy (CEA) may be complicated by cerebral embolism which often remains clinically silent. Unstable carotid plaques might increase the risk for peri-procedural embolism. We studied whether quantitative assessment of carotid plaque echogenity on ultrasound predicts the risk of cerebral ischaemia during CAS or CEA. In 50 consecutive patients with symptomatic carotid stenosis randomised to CAS ( n = 26) or CEA ( n = 24) in the International Carotid Stenting Study, semi-automated grey scale measurement of baseline carotid ultrasound images was performed. Grey-scale median, percentage of plaque area <20th percentile of grey-scale values, and an echographic risk index based on degree of stenosis and plaque area below the 20th percentile of grey-scale values were determined, both for the entire plaque and plaque surface. Brain MRI including diffusion-weighted imaging (DWI) was performed within 7 days before and 3 days after treatment as part of the ICSS–MRI substudy. The primary outcome on MRI was the presence of at least 1 new hyperintense DWI lesion after treatment. In the CAS group, patients with new DWI lesions after treatment ( n = 18) had significantly higher whole-plaque echographic risk indices at baseline (mean 0.1050) than patients without new lesions ( n = 8; mean 0.0263; p = 0.012). GSM was 26.7 for patients with and 34.3 for patients without lesions ( p = 0.163). Other measures of plaque echogenity did not differ significantly. In the CEA group, there were no significant differences in plaque echogenity measures between patients with ( n = 2) and those without DWI lesions ( n = 23). Our results show that among patients treated with CAS, the echographic risk index was higher in patients with new ischaemic brain lesions after treatment than in those without new lesions. Quantitative ultrasound plaque analysis may be helpful in estimating the risk of embolic complications in CAS.