Carotid web and ischemic stroke: a CT angiography study

Carotid web: Pathophysiology, diagnostic, and therapeutic options. A narrative review

A carotid web (CaWeb), otherwise known as a carotid bulb diaphragm, is a spur of intimal fibrous tissue extending into the carotid bulb. It is a rare, underdiagnosed cause of ischemic strokes in young people. The purpose of this narrative review was to provide an update on CaWebs, highlighting recent evolutions in their management. We undertook a comprehensive literature search on main electronic databases - MEDLINE/PubMed, Cochrane Library, Web of Science, and EMBASE - using a dedicated equation to include studies up to February 13, 2024. We also searched for the most recent guidelines about carotid disease or stroke including CaWeb management. A CaWeb is found in up to 10% of young patients, particularly young women, with severe anterior stroke due to an arterial-arterial embolism from the intra-nidus thrombus. Most patients with a CaWeb have less than 50% stenosis on duplex ultrasound, and diagnosis is mostly obtained by computed tomography angiography. When applying traditional stenosis criteria for symptomatic disease (> 50% stenosis), this highly morbid condition is easily overlooked, leading to recurrent strokes. Antithrombotic treatment is associated with a high recurrence rate of stroke after the index event. The first-line treatment of symptomatic CaWebs is increasingly based on endarterectomy or stenting. The lack of recommendations before 2021 and recent discordant guidelines make CaWeb management complex. No guidelines are available to manage patients with asymptomatic CaWebs. Results from ongoing multicenter registries will be useful in guiding management decisions.

Prevalence and clinical features of carotid artery web in patients undergoing endovascular thrombectomy for acute ischemic stroke

PURPOSE

Carotid artery web (CaW) is a rare focal fibromuscular dysplasia that can lead to embolic strokes with large vessel occlusion. This condition can be effectively treated with endovascular thrombectomy (EVT). Our study aims to assess the prevalence of CaW among patients with acute ischemic stroke (AIS) who underwent EVT and to compare the clinical characteristics of CaW with other carotid artery pathologies.

METHODS

We enrolled consecutive patients with AIS who underwent EVT at a single medical center and two regional teaching hospitals in Taiwan from September 2014 to December 2021. We compared CaW with carotid dissection (CaD) and carotid large artery atherosclerosis (CaLAA) in terms of patient demographics and thrombus histological findings.

RESULTS

Of the 576 AIS patients who underwent EVT, four (mean age: 50 years) were diagnosed with CaW, resulting in a prevalence of 0.69%. Among these four patients, three experienced successful reperfusion after EVT and achieved functional independence (defined as a modified Rankin Scale score ≤2) three months post-stroke. Importantly, none of the CaW patients suffered a recurrent stroke within one year. Patients with CaW were younger than those with CaD or CaLAA, and exhibited fewer vascular risk factors. Additionally, CaW was associated with distal occlusion sites. The thrombus composition in CaW patients was similar to that in CaD patients.

CONCLUSIONS

In conclusion, CaW is a rare finding among Asian patients with carotid artery disease who undergo for AIS. It is more prevalent in younger patients with a limited number of vascular risk factors.

Breakthrough of dual-phase CT angiography features of carotid web and its correlation with ischemic stroke

PURPOSE

To investigate the diagnostic value of dual phase CT angiography (CTA) in carotid web and its correlation with ischemic stroke.

METHODS

The imaging data of 726 patients with cervical CTA from January 2015 to November 2019 in Taizhou People's hospital were retrospectively and consecutively analyzed. A total of 16 patients with 23 carotid webs were obtained. The location, morphology and clinical data of 16 patients were observed. Carotid web was identified by two experienced radioimaging experts according to the characteristics of a thin intraluminal filling defect along the posterior wall of the carotid bulb on sagittal CTA and a septum structure in arteries on axial CTA.

RESULTS

In the arterial phase, 23 carotid webs in 16 patients showed membrane like separation in the lumen of the posterior wall of the carotid bulb, and one web extended into the internal and external carotid arteries in a "Y" shape. There were 9 males and 7 females. In venous phase, 16 carotid webs showed linear enhancement, and 15 sites showed delayed emptying of contrast medium at the lateral margin. Five patients were acute or chronic ischemic stroke. The kappa coefficient for interobserver agreement in diagnosing carotid web was 0.79.

CONCLUSION

Dual-phase CTA is effective and reliable method to identifying carotid webs, which may be associated with ischemic stroke.

Systematic review and meta-analysis of ipsilateral and contralateral carotid web prevalence in embolic supratentorial strokes of undetermined source

OBJECTIVES

A carotid web isdefined as an abnormal shelf-like projection of intimal fibrous tissue into the carotid bulb. Its presence may be an under-recognised source of embolic stroke of undetermined source (ESUS). The aim of this study was to investigate its prevalence in previously reported studies.

MATERIALS AND METHODS

A systematic literature review of Pubmed, EMBASE, and Scopus was conducted up until the 4/12/2021 using variations of the search terms - 'carotid web' and 'ischemic stroke'. Inclusion criteria were studies reporting carotid web prevalence in an ESUS cohort aged >18 years with adequate imaging. Secondary measures such as age, gender, ethnicity, and laterality were recorded. A meta-analysis of proportions was used to summarise the prevalence of webs along with a random-effects model to calculate the relative risk of ipsilateral and contralateral webs in ESUS.

RESULTS

The initial search yielded 361 articles, with 11 remaining post the inclusion and exclusion criteria. A meta-analysis of allage groups yielded a total carotid web prevalence among patients with stroke of unknown cause of 9.58 % (95 % CI 5.62 - 15.85). Carotid webs were more often detected in females (76.5 % ± 22.3 %), and in those of African heritage (58 % ± 39 %). In comparison with patients without an ischemic stroke, there was a significant association found for an ipsilateral carotid web (risk ratio of 2.74 (95 % CI: 2.14 - 3.51)) but no association found for contralateral webs (risk ratio of 1.50 (95 % CI: 0.94 - 2.40)).

CONCLUSION

The prevalence of ipsilateral carotid webs associated with ESUS is substantial, and may be more common in females and in individuals of African descent.

Importance of multiplanar reformation angiographic images for the detection of carotid web: A case series

Carotid web (CW) is considered a variant of intimal fibromuscular dysplasia. CW represents between 9.4% and 37% of ischemic strokes that were initially misclassified as "cryptogenic." However, in Latin America, there is a lack of detection. We present 5 cases of ischemic stroke due to CW and discuss the usefulness of multiplanar reformatting (MPR) imaging in computed tomography angiography. The identification of CW with the use of tridimensional (3D) reconstructions and maximum intensity projection was 20%, the rest was misdiagnosed as atherosclerotic plaque. With the MPR, the identification of typical CW findings was improved, such as a thin septum, a shelf-like image, and a mountain shadow-like image. However, one must be alert to changes in the 3D disposition of the carotid bifurcation, as they may mask the typical CW findings. A good practice is to align the internal carotid artery exactly posterior to the external carotid artery in the sagittal plane.

Multimodality imaging of carotid web: A case report and literature review

Objectives

The carotid web is a compelling potential mechanism of cryptogenic stroke. It is easy for it to escape diagnosis or be misdiagnosed, since it rarely causes hemodynamic stenosis. Currently, there is a lack of consensus on the prevalence, etiology, imaging evaluation, and treatment strategy of carotid artery. We aimed to present the multimodal imaging of carotid web and comprehensively review the characteristics of carotid web.

Methods

A 38 year-old man with carotid web, who presented with acute left hemispheric syndrome, was not identified by computed tomography angiography and high-resolution magnetic resonance imaging in the initial report, but were identified in retrospect and then confirmed by digital subtraction angiography and histopathology. A literature review of carotid web was performed to identify prevalence, nature history, imaging tools, and optimal management of carotid web.

Results

80 reports including 681 patients with carotid web were identified. The prevalence of symptomatic carotid web was 1.2% in patients with transient ischemic attack/stroke, 6.4% in patients with cryptogenic ischemic stroke, 1.1% in patients with large vessel occlusion stroke, and 4.4% in patients who operated on for carotid stenosis. A total of 23.0% patients had bilateral carotid web. In most patients, carotid web was located on the posterior wall (87.3%) of the carotid artery (98.7%). The mean length was 3.3 mm and mean stenosis rate was 20.9%. A total of 31.6% percent patients had thrombus trapped in carotid web and 75.9% patients had large vessel occlusion. Computed tomography angiography and digital subtraction angiography were favorable tools to detect carotid web. There were rare periprocedural complications and no recurrent strokes in carotid revascularization patients.

Conclusions

carotid web is an under-recognized cause of ischemic stroke. It is easy to be missed or misdiagnosed. Carotid revascularization can effectively prevent recurrent stroke for patients with symptomatic carotid web. Clinicians should strength their learning and understanding of carotid web.

Fibromuscular Dysplasia/Carotid Web in Angio-CT Imaging: A Rare Cause of Ischemic Stroke

Background and Objectives: Carotid web (CaW) is an intimal variant of fibromuscular dysplasia and may constitute as one of rare causes of acute ischemic stroke (AIS). The objective of this study was to determine the prevalence of CaW in patients with AIS or transient ischemic attack (TIA) based on head/neck CT angiography (CTA) in a Polish cohort study. Materials and Methods: A retrospective study was performed by analyzing 1480 electronic clinical and imaging data regarding patients with AIS or TIA, hospitalized in the years 2018–2020 in the authors’ institution. The final sample consisted of 181 patients who underwent head/neck CTA; aged 67.81 ± 13.51 years (52% were women). All head/neck CTA studies were independently evaluated by two radiologists. The patient’s clinical condition was assessed with the National Institutes of Health Stroke Scale (NIHSS, 5.76 ± 4.05 and 2.88 ± 3.38 at admission and at discharge, respectively). Results: 27 patients were identified with CaW. The prevalence of CaW in the final sample (181 pts with good quality CTA) was 14.9%. In the CaW group, 89% patients had AIS, including 26% diagnosed with recurrent and 11% with cryptogenic strokes. There were no significant differences between the presence of CaW and gender, age, NIHSS score, recurrent or cryptogenic stroke. Conclusions: Our study demonstrated that CaW may be an underrecognized entity leading to cerebrovascular events. The diagnosis of CaW depends on a high level of awareness and a comprehensive analysis of the neuroimaging studies. Our findings support the hypothesis that it is worthwhile to perform CTA to determine the etiology of ischemic stroke, particularly if predicting factors were not identified.

Ipsilateral internal carotid artery web and acute ischemic stroke: A cohort study, systematic review and meta-analysis

Introduction

The carotid web is a compelling potential mechanism of embolic ischemic stroke. In this study, we aim to determine the prevalence of ipsilateral carotid web in a cohort of ischemic stroke patients and to perform a systematic review and meta-analysis of similar cohorts.

Patients & methods

We performed a retrospective, observational, cohort study of acute ischemic stroke patients admitted to a comprehensive stroke center from June 2012 to September 2017. Carotid web was defined on computed tomography angiography (CTA) as a thin shelf of non-calcified tissue immediately distal to the carotid bifurcation. We described the prevalence of carotid artery webs in our cohort, then performed a systematic review and meta-analysis of similar cohorts in the published literature.

Results

We identified 1,435 potentially eligible patients of whom 879 met criteria for inclusion in our analysis. An ipsilateral carotid web was detected in 4 out of 879 (0.45%) patients, of which 4/4 (1.6%) were in 244 patients with cryptogenic stroke and 3/4 were in 66 (4.5%) patients <60 years old with cryptogenic stroke. Our systematic review yielded 3,192 patients. On meta-analysis, the pooled prevalence of ipsilateral carotid web in cryptogenic stroke patients <60 was 13% (95% CI: 7%-22%; I² = 66.1%). The relative risk (RR) of ipsilateral versus contralateral carotid web in all patients was 2.5 (95% CI 1.5–4.2, p = 0.0009) whereas in patients less than 60 with cryptogenic stroke it was 3.0 (95% CI 1.6–5.8, p = 0.0011).

Discussion

Carotid webs are more common in young patients with cryptogenic stroke than in other stroke subtypes. Future studies concerning the diagnosis and secondary prevention of stroke associated with carotid web should focus on this population.

Assessment of Recurrent Stroke Risk in Patients With a Carotid Web

Importance

A carotid web (CW) is a shelf-like lesion along the posterior wall of the internal carotid artery bulb and an underrecognized cause of young stroke. Several studies suggest that patients with symptomatic CW have a high risk of recurrent stroke, but high-quality data are lacking.

Objective

To assess the 2-year risk of recurrent stroke in patients with a symptomatic CW.

Design, Setting, and Participants

A comparative cohort study used data from the MR CLEAN trial (from 2010-2014) and MR CLEAN Registry (from 2014-2017). Data were analyzed in September 2020. The MR CLEAN trial and MR CLEAN Registry were nationwide prospective multicenter studies on endovascular treatment (EVT) of large vessel occlusion (LVO) stroke in the Netherlands. Baseline data were from 3439 consecutive adult patients with anterior circulation LVO stroke and available computed tomography (CT)-angiography of the carotid bulb. Two neuroradiologists reevaluated CT-angiography images for presence or absence of CW and identified 30 patients with CW ipsilateral to the index stroke. For these 30 eligible CW participants, detailed follow-up data regarding stroke recurrence within 2 years were acquired. These 30 patients with CW ipsilateral to the index stroke were compared with 168 patients without CW who participated in the MR CLEAN extended follow-up trial and who were randomized to the EVT arm.

Main Outcomes and Measures

The primary outcome was recurrent stroke occurring within 2 years after the index stroke. Cox proportional hazards regression models were used to compare recurrent stroke rates within 2 years for patients with and without CW, adjusted for age and sex. The research question was formulated prior to data collection.

Results

Of 3439 patients with baseline CT-angiography assessed, the median age was 72 years (interquartile range, 61-80 years) and 1813 (53%) were men. Patients with CW were younger (median age, 57 [interquartile range, 46-66] years vs 66 [interquartile range, 56-77] years; P = .02 and more often women (22 of 30 [73%] vs 67 of 168 [40%]; P = .001) than patients without CW. Twenty-eight of 30 patients (93%) received medical management after the index stroke (23 with antiplatelet therapy and 5 with anticoagulant therapy). During 2 years of follow-up, 5 of 30 patients (17%) with CW had a recurrent stroke compared with 5 of 168 patients (3%) without CW (adjusted hazard ratio, 4.9; 95% CI, 1.4-18.1).

Conclusions and Relevance

In this study, 1 of 6 patients with a symptomatic CW had a recurrent stroke within 2 years, suggesting that medical management alone may not provide sufficient protection for patients with CW.

Carotid web prevalence in a large hospital-based cohort and its association with ischemic stroke

Carotid artery webs are shelf-like protrusions of intimal fibrous tissue arising from the posterior wall of the carotid bulb, found to have a 2.3% prevalence in the United States. Previous studies have demonstrated its association with ipsilateral anterior circulation stroke. The aim of this study is to assess the prevalence of carotid webs in the largest US epidemiologic study to date, and to further characterize the clinical features of carotid web patients. We assembled a cohort of 1467 adult patients with CT angiogram neck from January 1, 2011 to January 1, 2017. CT angiograms were reviewed for diagnosis of carotid web. Demographic and clinical details of web patients were obtained. Differences in demographics and CT angiogram indication between patients with and without carotid web were assessed using appropriate statistical tests. Twenty-four (24/1467 = 1.6%) carotid web patients were identified (mean age: 63 years; 62.5% female; 50% African American). Twelve (12/24 = 50%) had ipsilateral anterior circulation stroke. Of them, 8 were deemed cryptogenic. Four (4/24 = 16.7%) web patients had at least one recurrent stroke in the ipsilateral anterior circulation. One case was reported on the radiology report at the time the study was initially performed. This study confirms a prevalence of 1.6% in our urban, North American cohort. Among carotid web patients, there was a high incidence of ipsilateral anterior circulation stroke, the majority of which were classified as cryptogenic. This study affirms the importance of the diagnosis of carotid web, especially in cryptogenic stroke patients, as a potential unrecognized stroke risk factor.