Abstract 212: Factors Associated with Symptom Development in Asymptomatic Carotid Artery Stenosis: Multimodal Carotid and Perfusion Imaging Study

Background: The predictors of symptom development in asymptomatic carotid stenosis are still unclear. We sought to identify factors associated with symptom development in asymptomatic carotid stenosis using multimodal imaging technique. Methods: We retrospectively collected patients who had carotid artery revascularization procedures (carotid endarterectomy [CEA] or carotid artery stenting [CAS]) from April 2007 to May 2013. Patients who had event of cerebral ischemic stroke during 6 months before CEA or CAS were categorized as a symptomatic carotid stenosis. Results from carotid Duplex sonography, CT angiography, brain MRI and MRA, perfusion-weighted MRI (PWI), and demographic profiles were compared. Multivariate logistic regression analysis was performed to identify factors associated with symptom carotid stenosis. Results: A total of 684 patients (asymptomatic 58%, symptomatic 42%) with carotid stenosis more than 50% were included. The presence of ischemic heart diseases, peripheral artery occlusive disease and use of statin were higher in the asymptomatic carotid stenosis. On Duplex scan, ulceration, echolucent plaque, and heterogeneous components of plaque were more frequent in symptomatic carotid stenosis. Angiographic data showed the length of plaque was longer in symptomatic carotid stenosis. Presence of deep white matter hyperintensity, FLAIR vessel sign and GRE vessel sign were more frequently observed in symptomatic carotid stenosis. Patients with symptomatic carotid stenosis had increased cerebral blood flow, cerebral blood volume (CBV), and delayed time to peak when compared to the asymptomatic stenosis. Multivariate analysis revealed length of plaque (>20mm), deep white matter hyperintensity and increased CBV were associated with symptomatic carotid stenosis (Odd ratio [OR]=2.339, 95% confidence interval [CI] 1.312-4.169, P=0.004; OR=2.315, 95% CI 1.160-4.619, P=0.017; OR=2.242, 95% CI 1.127-4.463, P=0.021, respectively). Conclusion: Plaque burden, deep white matter hyperintensity, and increased CBV were independent predictors of symptom development in carotid stenosis. Multimodal imaging may be useful to identify high risk patients of ischemic stroke among asymptomatic carotid stenosis.