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]
Carotid artery web

Epidemiology

Clinical presentation

  • often an asymptomatic, incidental lesion
  • thrombus formation can lead to recurrent stroke or transient ischemic attack (TIA)

Diagnostic evaluation

  • 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

 

Carotid artery web on ultrasound
Carotid artery web

Differential diagnosis

  • dissection
    • usually longer lesion, localized distally (typically below the skull base) The left ICA dissection with distinct "string sign"
    • irregular margins, sometimes featuring a double lumen
  • atherosclerotic plaque
    • different shape, irregular margins or ulcerations  Atherosclerotic plaques in carotid bifurcation on CTA
    • often accompanied by calcifications
Differential diagnosis of carotid artery web

Management

Acute stroke therapy

Stroke prevention

  • 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 treatmentantiplatelet 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)

FAQs

  • 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
  • often asymptomatic; rarely it may manifest as ischemic stroke
  • 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

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Carotid artery web
link: https://www.stroke-manual.com/carotid-artery-web/