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This paper aimed to characterize carotid webs and their association with ipsilateral ischemic stroke. A carotid web was defined as a thin intraluminal filling defect located along the posterior wall of the carotid bulb just beyond the carotid bifurcation. Lesions were characterized on oblique sagittal section CT angiography (CTA) and had the appearance of a septum on axial images.
Over 1 year, 7 patients with a carotid web and ipsilateral ischemic stroke were prospectively identified at a single centre. The mean patient age was 50 years. Five were women and five had a history of recurrent stroke in the relevant internal carotid artery territory. One patient had 4 strokes in the same vascular territory. In 2 patients, thrombus-like material was seen at the site of the web with an evolving morphology on serial CTAs despite concurrent antiplatelet therapy. In one, the thrombus resolved in response to a change in therapy to include anticoagulation with heparin. All of these patients had no other cause for stroke identified after standard work up.
Four of the patients with recurrent strokes underwent carotid endarterectomy and subsequently remained stroke free at last follow up. The endarterectomy specimens demonstrated marked fibroelastic thickening of the intima. In 1, there was a shelf of intimal fibrosis projecting into the lumen. In 2, the fibrous intimal tissue was fissured by dissection. One of these dissected specimens showed organized hemorrhage within and the other formed an open, endothelium-lined cavity. The last specimen contained a thick fibrous intimal cushion with evidence of recent mural thrombus.
A separate retrospective analysis of 576 consecutive patients presenting with suspected stroke was performed in order to estimate the period prevalence of carotid webs. Seven patients with a carotid web were identified. The prevalence in this series was 1.2%. Two had acute stroke in the vascular territory of the carotid web.
In summary, the authors state that carotid webs, though rare, appear to be associated with recurrent ipsilateral stokes in a prospective case series. They found a 1 year period prevalence of carotid webs in a retrospective acute stroke presentation population of approximately 1.2%. The fibrous thickening seen on pathology, the authors suggest, may be a feature of the intimal variant of fibromuscular dysplasia. They postulate that the morphology rather than the histology of the web may be the main determinant of thrombogenicity, related to turbulence and stasis in the cul-de-sac created upstream to the web. They suggest that, like in the left atrial appendage, thrombus formation in this environment may potentially respond best to anticoagulants rather than antiplatelet medications. Further research will be required to better delineate the epidemiology and natural history of carotid webs identified on CTA as well as the most appropriate therapeutic approach.
