Clinical, imaging, and management features of symptomatic carotid web: Insight from CAROWEB registry

Subjects with carotid webs demonstrate pro-thrombotic hemodynamics compared to subjects with carotid atherosclerosis

Carotid artery webs (CaW) are non-atherosclerotic projections into the vascular lumen and have been linked to up to one-third of cryptogenic strokes in younger patients. Determining how CaW affects local hemodynamics is essential for understanding clot formation and stroke risk. Computational fluid dynamics simulations were used to investigate patient-specific hemodynamics in carotid artery bifurcations with CaW, bifurcations with atherosclerotic lesions having a similar degree of lumen narrowing, and with healthy carotid bifurcations. Simulations were conducted using segmented computed tomography angiography geometries with inlet boundary conditions extracted from 2D phase contrast MRI scans. The study included carotid bifurcations with CaW (n = 13), mild atherosclerosis (n = 7), and healthy bifurcation geometries (n = 6). Hemodynamic parameters associated with vascular dysfunction and clot formation, including shear rate, oscillatory shear index (OSI), low velocity, and flow stasis were calculated and compared between the subject groups. Patients with CaW had significantly larger regions containing low shear rate, high OSI, low velocity, and flow stasis in comparison to subjects with mild atherosclerosis or normal bifurcations. These abnormal hemodynamic metrics in patients with CaW are associated with clot formation and vascular dysfunction and suggest that hemodynamic assessment may be a tool to assess stroke risk in these patients.

Carotid webs: a review of pathophysiology, diagnostic findings, and treatment options

A carotid web (CaW) is an atypical form of fibromuscular dysplasia characterized by a fibrous, shelf-like intimal flap originating from the posterior wall of the internal carotid bulb projecting into the arterial lumen. CaWs disturb normal blood flow and create stasis between the intimal reflection and the carotid wall, thereby promoting thrombogenesis and increasing the risk of downstream embolic strokes. Observational data have suggested that CaWs are associated with strokes with otherwise unknown etiology, particularly in young patients without other stroke factors, and stroke recurrence rates of symptomatic CaWs have been reported to be as high as 20% over 2 years. Despite its clinical importance, there are currently no clear guidelines on the management of CaWs. In this narrative review, we discuss the epidemiology, pathogenesis, pathophysiology, diagnosis, and treatment options for this under-recognized entity.