Carotid artery web

David Goldemund M.D.
Updated on 14/03/2024, published on 12/01/2023


  • the carotid artery web (CaW) is characterized by a thin fibrous 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 for this condition: 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
    • associated with an increased risk of cryptogenic and recurrent ischemic stroke (studies have shown an incidence rate of 8.9% for carotid web in cryptogenic stroke, compared to 1.9% in the control group)   [Coutinho, 2017]
    • its thrombogenic potential is attributed  to blood stasis along the downstream surface of the web, which may increase the risk of intracranial thromboembolism  [Compagne, 2019]
Carotid artery web


Clinical presentation

  • 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]
    • carotid artery web is a significant cause of “cryptogenic stroke” in young patients

Diagnostic evaluation

  • neurosonology
    • an echogenic membrane-like structure protruding into the lumen from the posterior wall at the beginning of the ICA
    • concurrent hypoechoic thrombus with possible stenosis may co-occur  (Ning, 2020)
    • ultrasound is less reliable than CT angiography (CTA) – carotid webs could be easily confused with ulcerations on the surface of the atherosclerosis plaque
    • optimal methods for evaluation
    • 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
    • considered the 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


Acute stroke therapy

Stroke prevention

  • there is limited evidence to establish a clear preference between medication and CEA/CAS; some smaller studies report a lower risk of stroke with invasive therapy
  • data regarding the management of asymptomatic lesions is insufficient
  • medical treatment – current guidelines recommend antiplatelet drugs
    • recommended for all stroke (symptomatic) patients  (AHA/ASA 2021 1/B-NR)
    • antiplatelets may be considered for asymptomatic lesions, although the benefit is not well defined
    • indication for anticoagulation is unclear (may be considered in patients with proven concurrent thrombosis);  data are limited
    • the comparative efficacy of SAPT, DAPT, or anticoagulation is unknown
    • medical management alone may not provide adequate protection due to high recurrence risk  [Guglielmi, 2021] [Zhang, 2018]
    • patients with symptomatic CaW have as high as a 20% risk of stroke recurrence over 2 years (Olindo, 2021)
    • invasive therapy should be considered for patients with webs causing significant stenosis and recurrent stroke despite the best medical treatment (BMT)  (AHA/ASA 2021 2b/C-LD)
    • CaW may be safely and effectively treated with carotid stenting; CEA also allows for histological assessment of CaWs to confirm the diagnosis (Haynes, 2020)


  • a rare vascular abnormality characterized by an intimal shelf-like protrusion within the carotid artery, typically at the level of the carotid bulb
  • this web can disrupt laminar blood flow, predisposing to thrombus formation and subsequent embolic 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 thin, linear, membrane originating from the posterior carotid artery wall and protruding into the vessel lumen
  • in the B‐mode, under longitudinal view, the characteristic appearance of CaW is a triangular lesion protruding into the artery lumen
  • CAW is often asymptomatic
  • rarely, thrombus formation may lead to artery-to-artery embolic event, particularly in young and middle-aged adults without traditional cardiovascular risk factors
  • there are no well-defined risk factors for CAW, unlike atherosclerotic disease, which is associated with traditional cardiovascular risk factors
  • management strategies include medical and procedural interventions
  • medical management is often the first-line treatment and typically involves antiplatelet therapy or anticoagulation
  • in selected cases, especially those with recurrent strokes despite optimal medical therapy, endovascular treatment with stenting or surgical intervention such as carotid endarterectomy may be considered
  •  vascular imaging (usually ultrasound or MRA) can be used to monitor the condition and assess the effectiveness of treatment
  • CAW is a structural anomaly related to fibromuscular dysplasia, presenting as an intimal flap or web that predisposes to thrombus formation without a significant stenosis
  • atherosclerosis involves the formation of plaques that can narrow the arterial lumen and cause hypoperfusion or embolic events (caused by dislodged atheroma masses or thrombi)
  • carotid web can be distinguished from dissection by its characteristic location and appearance, being thin and focal in nature and exclusively located in the posterior wall of the carotid bulb
  • more studies are needed for a better understanding carotid web origin; it is considered to be a rare variant of fibromuscular dysplasia (FMD)

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Carotid artery web