Carotid artery web

Created 12/01/2022, last revision 30/11/2023

Definition

the carotid artery web is characterized by a thin membrane extending from the posterior wall of the carotid bulb into the lumen, just above the bifurcation; it is considered a variant of fibromuscular dysplasia [Kim, 2019]
- various synonyms are used: carotid weblike formation, carotid pseudovalvular fold, carotid diaphragm
a relatively rare vascular pathology, increasingly recognized as an important cause of ischemic stroke in patients without traditional cardiovascular risk factors
- it is a significant risk factor for cryptogenic and recurrent ischemic stroke (the incidence rate of carotid web in cryptogenic stroke is 8.9% vs. 1.9% in the control group) [Coutinho, 2017]
- its thrombogenic potential is caused by blood stasis along the downstream surface of the web, which can lead to intracranial thromboembolism [Compagne, 2019]

a relatively rare finding (approximately 1-2.5% of CTAs performed) (Coutinho, 2017) [Compagne, 2017]
more common in women

often an asymptomatic, incidental lesion
thrombus formation can lead to recurrent stroke or transient ischemic attack (TIA)
- recurrence occurs in up to 29% of patients despite medical treatment [Haussen, 2019]
- the web is a significant cause of “cryptogenic stroke” in young patients

neurosonology
- an echogenic lesion in the posterior wall of the ICA above the bifurcation
- hypoechoic thrombus with possible significant stenosis may be seen
- method is less reliable than CT angiography (CTA)
CTA/MRA
- optimal method of choice
- view both axial and sagittal sections
- the carotid web appears as a thin shelf-like or linear filling defect in the posterior wall of the carotid bulb
  - hypodense thrombus is found in up to 25% of cases
DSA
- gold standard
- carotid web is typically detected during an endovascular procedure
- always look for oblique projections
- signs of contrast stagnation may sometimes be visible in the venous phase

dissection
- usually longer lesion, localized distally (typically below the skull base)
- irregular margins, sometimes featuring a double lumen
atherosclerotic plaque
- different shape, irregular margins or ulcerations
- often accompanied by calcifications

there is little data to establish a clear preference between medication and CEA/CAS); some smaller series report a lower risk of stroke with invasive therapy
data on the management of asymptomatic lesions is lacking
medical treatment – antiplatelet drugs
- recommended for all stroke patients (AHA/ASA 2021 1/B-NR)
- consider in asymptomatic lesions, though the benefit remains unclear
- indication for anticoagulation is unclear (may be considered in patients with proven concurrent thrombosis)
CEA/CAS
- medical management alone may not provide sufficient protection due to the high recurrence risk [Guglielmi, 2021] [Zhang, 2018]
- invasive therapy should be considered for patients with webs causing significant stenosis and recurrent strokes occurring despite the best medical treatment (BMT) (AHA/ASA 2021 2b/C-LD)

a rare vascular abnormality characterized by a shelf-like intraluminal membrane in the carotid bulb, which can predispose individuals to ischemic stroke
its exact prevalence is not well-documented due to its rarity and often asymptomatic nature

vascular imaging, such as carotid ultrasound, CT or MR angiography, is used to visualize the web-like structure in the artery

treatment options include antithrombotic therapy, such as antiplatelet or anticoagulant medications, and in some cases, surgical intervention like carotid endarterectomy or stenting
the decision for surgery depends on individual risk factors, symptoms, and the severity of the web
medical management is often the first-line treatment

vascular imaging follow-up (usually with ultrasound) can monitor the condition and assess the effectiveness of treatment