Abstract TP222: Prevalence of Carotid Web in Patients With Cryptogenic Stroke

Abstract

Introduction: Carotid web is a putative mechanism of cryptogenic ischemic stroke. We aimed to determine the prevalence of carotid web based on assigned stroke mechanism, and hypothesized that carotid webs would be found more frequently in younger cryptogenic stroke patients. Methods: We performed a single-center retrospective cohort study using institutional registry data from consecutive patients with confirmed anterior circulation ischemic stroke between July 2015-September 2017. We reviewed all available computed tomography angiogram (CTA) studies of the neck, and excluded patients who did not have a high-quality CTA of the neck performed. Carotid web was defined as a thin shelf of non-calcified tissue protruding into the lumen of the internal carotid artery immediately distal to the bifurcation, best visualized on sagittal oblique imaging and evident as a small septum on axial imaging. Stroke subtype was adjudicated a priori using validated methods, and we compared relevant risk factors in patients with cryptogenic stroke with and without carotid web. Results: We identified 882 patients with anterior circulation stroke who had a CTA neck available for review (49.3% male, 30% cryptogenic). A total of 7 patients (0.8%) were found to have carotid webs, of which 4 were ipsilateral to a patient’s stroke; all patients with ipsilateral carotid webs were adjudicated to have cryptogenic stroke. Patients with carotid web were younger than other patients in our cohort (age 49.0±14.6 vs. 72.2±14.9 years, p=0.003), and none of them had a history of hypertension (0% vs. 72%, p=0.04). In patients with cryptogenic stroke, overall prevalence of carotid webs was 1.5%, but the prevalence was significantly higher in younger cryptogenic stroke patients (age <60: 4.8%; age ≥60: 0.5%; p=0.01). Imaging findings that mimicked carotid webs, including non-calcified atherosclerosis and small protruding lesions, were prevalent in 8.3% of all patients. Discussion: Carotid web may represent an under-recognized occult mechanism of cryptogenic stroke, particularly amongst younger patients.