Carotid Bulb Webs as a Cause of "Cryptogenic" Ischemic Stroke

Transcarotid arterial revascularization for symptomatic carotid web

OBJECTIVES

Symptomatic carotid web is an increasingly recognized cause of acute ischemic stroke with a high risk of recurrent ischemic events despite aggressive medical interventions. Surgical interventions including transfemoral carotid artery stenting (TFCAS) and carotid endarterectomy have been described to reduce this risk, but transcarotid arterial revascularization (TCAR) has not been evaluated for this purpose.

MATERIALS AND METHODS

Patients with cerebral ischemia from carotid web underwent TCAR with flow reversal. Patients were monitored for periprocedural complications and assessed at follow-up for clinical evidence of recurrent ischemia.

RESULTS

Six cases over the course of 21 months were identified, 2 males and 4 females with a median age of 59.5 (interquartile range of 39). All underwent technically successful TCAR without periprocedural complications no post-procedural cerebral ischemia over a median follow-up time of 21 months.

CONCLUSIONS

In this small series of patients, TCAR provided a safe and effective treatment of carotid webs that had previously caused cerebral ischemia.

Treatment of Symptomatic Carotid Webs

BACKGROUND

The present study aims to describe the clinical characteristics and treatment outcomes of patients with symptomatic carotid web treated at a single institution in South America.

METHODS

Retrospective study of a single-center experience of patients with carotid webs surgically treated from September 2019 to September 2023.

RESULTS

Ten patients had carotid webs, 6 (60%) were females. Median age was 54.5 years (range: 35-77 years). All patients were symptomatic. Diagnosis was made in 90% (n = 9) of the patients with either computed tomography angiography or magnetic resonance alone. One (10%) patient underwent angiography for definite diagnosis. The median interval from the first neurological event to intervention was 90 months (range: 3 days-108 months). Four (40%) patients underwent surgical treatment within 1 month from symptom onset and carotid web diagnosis, with a median of 3.5 days (range: 3-9 days). Six (60%) patients underwent delayed surgical treatment since the cause of the neurological event was uncertain, with a median of 54 months (range: 6-108 months). These 6 patients had recurrent neurological events. Three (30%) patients underwent carotid endarterectomies with polyurethane patch and 3 (30%) by eversion technique. Three (30%) patients underwent segmental resection and reanastomosis of the internal carotid artery. One underwent internal carotid artery plasty with saphenous vein. At a median follow-up of 30 months (range: 6-46 months), 1 patient persists with mild aphasia, another patient has severe aphasia and right hemiparesis, both as sequelae of their initial strokes, and another patient has suffered 3 nonischemic episodes of brief transient right hemiparesis attributed to epileptic seizures. The other 7 patients remain without new neurological events.

CONCLUSIONS

Neurological events of carotid distribution deserve accurate imaging work up, keeping in mind the diagnosis of carotid web. Surgical treatment for carotid web seems effective for preventing recurrences; nevertheless, further studies are warranted to define the best management for these patients.

Multiplane reconstruction modifies the diagnostic performance of CT angiography in carotid webs

INTRODUCTION

Carotid Web (CaW) represents an overlooked stroke etiology and has been associated with high recurrence rates and to be amenable to stenting. We evaluated the diagnostic performance of different computed tomography angiography (CTA) projections in CaW.

METHODS

Consecutive patients <65 years-old with symptomatic CaW (n=31), carotid atherosclerosis (n=27), or normal carotids (n=49) diagnosed with a thin-cut CTA were included. Deidentified CTAs were independently reviewed by three readers, who recorded the diagnosis and level of certainty after evaluating the axial plane alone, after adding sagittal/coronal maximum intensity projection (MIP), then after oblique MPR reformats.

RESULTS

There were 93 total CaW, 81 atherosclerosis, and 147 normal carotid reads. With CTA axial projection alone, less CaW cases (44.1 %) were appropriately diagnosed as compared to atherosclerosis (87.7 %; p<0.001) and normal carotid (83 %; p<0.001) cases. Sagittal/coronal MIPS increased the rate of accurate CaW diagnosis (44.1-76.3 %; p<0.001). Inter-rater agreement in CaW detection increased from k= 0.46 (0.35-0.57) using axial to k= 0.80 (0.69-0.91) with sagittal/coronal planes. The axial projection alone had lower sensitivity (44 % vs. 76 %) but similar specificity (95 % vs. 96 %) in CaW detection compared to axial+ sagittal/coronal MIPS. The accuracy in detecting atherosclerosis or normal carotids did not increase after adding sagittal/coronal MIPS and oblique MPRs. The certainty level for CaW diagnosis was lower when compared to atherosclerosis and normal carotids using axial alone (3.0 [3.0-4.0] vs. 4.0 [3.0-5.0]; p<0.001 and 4.0 [3.0-5.0]; p<0.001) as well as after adding sagittal/coronal MIPS (4.0 [3.0-5.0] vs. 5.0[4.0-5.0]; p=0.01 and 4.0 [4.0-5.0]; p<0.001).

CONCLUSION

CTA axial plane alone was insufficient for CaW detection. CTA sagittal/coronal MIP reconstructions as well as oblique MPR reformats enhanced the accuracy and confidence related to CaW diagnosis.

Treatment of Symptomatic Carotid Webs: A Single-Center Review

BACKGROUND

Carotid webs are abnormal thin shelf-like or flap-like tissue in the carotid bulb (proximal internal carotid artery). Rarely are carotid webs detected prior to symptoms since routine carotid artery surveillance is not performed in younger individuals without traditional risk factors for carotid disease. The cause and natural history remain unknown. In general, they are not common but should be considered in the differential diagnosis of a patient who presents with ischemic neurologic symptoms. The web can create a flow disturbance, potentiating local thrombus formation, which can embolize producing resulting in cerebral ischemia. Current treatment is to reduce thrombus formation (antithrombotics and/or anticoagulation) or to alter the flow disturbance caused by the web (surgical removal or stent).

METHODS

We retrospectively identified all patients presenting with acute ischemic stroke to our Comprehensive Stroke Center that were diagnosed with carotid web from January 2020 to December 2023. Patient demographics, presentation, hospital course including treatment and complications were collected and reported.

RESULTS

Fifteen patients presented with carotid web and stroke from 2020 to 2023 and 13 underwent carotid artery stenting or endarterectomy with no periprocedural complications. Most (40%) carotid webs were not primarily identified by the initial radiology interpretation.

CONCLUSIONS

We discuss our experience of carotid web and its management as well as review of the current literature.

In-hospital recurrent stroke in ipsilateral carotid web patients undergoing thrombectomy

OBJECTIVE

Carotid artery web is a possible cause of ischemic stroke, especially in young patients who lack conventional risk factors. The immediate and long-term outcomes are not well studied. We aimed to determine the association between an ipsilateral carotid web and in-hospital stroke recurrence.

METHODS

We analyzed data from adult patients admitted with an acute anterior circulation large vessel occlusion at a Comprehensive Stroke Center between July 2015 and March 2023. The primary outcome was in-hospital stroke recurrence and secondary outcome was in-hospital recurrent LVO. Multivariable logistic regression was performed to examine the association between ipsilateral carotid web and recurrent ischemic stroke and recurrent LVO.

RESULTS

Of the 1463 patients with anterior circulation large vessel occlusion, 27 (1.8%) had an ipsilateral carotid artery web. Patients with carotid web were younger (median age (IQR), 60 years (53-67 years) versus 74 years (62-84 years), P < 0.01) and less likely to be Caucasian (60% vs. 80%, p = 0.014). Of the 27 patients with carotid web, 18 (70%) had no identifiable competing stroke mechanism. When compared to patients without ipsilateral carotid web, those with an ipsilateral carotid web had a higher risk of recurrent ischemic stroke (adjusted RR: 4.38, 95% CI: 1.38-13.85) and recurrent ipsilateral large vessel occlusion (adjusted RR: 4.49, 95% CI: 1.41-14.21).

INTERPRETATION

Carotid webs are an under recognized cause of acute large vessel occlusion and are associated with higher risk of early recurrence. Studies are needed to validate our findings and test early revascularization strategies in patients with symptomatic carotid artery webs.

Carotid web catheter angiography hemodynamic parameters

BACKGROUND

Carotid web (CaW)-related contrast stagnation on digital subtraction angiography (DSA) may be a marker supporting the pathophysiological theory of stasis and thrombosis/embolization. We aim to assess the correlation between DSA hemodynamic parameters with CT angiography (CTA) structural measurements and clinical characteristics.

METHODS

Cross-sectional analysis of consecutive patients with CaW who underwent CTA+DSA. DSA-derived hemodynamic parameters were calculated based on a region of interest at the carotid bulb (time-density curves; TDC). The correlation between duration of contrast stagnation with CaW structural features and with clinical characteristics was evaluated with a mixed effects model.

RESULTS

Sixty patients of mean±SD age 52.2±10.3 years were included, of whom 38 (63.3%) were women, 51 (85%) were black, and 59 (98.3%) had symptomatic lesions. The median CaW base was 2.46 mm (range 1.95-3.76), length 2.7 mm (range 2.15-3.96), thickness (length/base) 1.05 (IQR 0.81-1.36), caudal angle 31.93° (IQR 22.35-43.58), mean±SD distal angle 66.91±15.84°, pocket area 1.62 mm² (0.96-1.62), and pocket perimeter 6.03±2.6 mm. The TDC consistently showed an initial fast decay from the peak concentration followed by a plateau with a negative exponential pattern. The median stagnation time from peak density to 80% contrast clearance was 2.91 s (range 1.81-4.94). No significant associations were observed between the stagnation time and CaW CTA structural measurements (length/base/thickness, caudal and cranial angles web surface angles, web pocket area/perimeter) or clinical characteristics.

CONCLUSIONS

A negative exponential pattern in the DSA contrast clearance of the CaW pocket was observed. There were no morphological or clinical features clearly associated with the duration of contrast stagnation on DSA. The hemodynamic disruption caused by CaW and its thrombotic risk may not be appropriately measured by contrast stagnation time.

Assessment of Complex Flow Patterns in Patients With Carotid Webs, Patients With Carotid Atherosclerosis, and Healthy Subjects Using 4D Flow MRI

BACKGROUND

Carotid webs (CaWs) are fibromuscular projections in the internal carotid artery (ICA) that cause mild luminal narrowing (<50%), but may be causative in up to one-third of seemingly cryptogenic strokes. Understanding hemodynamic alterations caused by CaWs is imperative to assessing stroke risk. Time-Average Wall Shear Stress (TAWSS) and Oscillatory Shear Index (OSI) are hemodynamic parameters linked to vascular dysfunction and thrombosis.

PURPOSE

To test the hypothesis: "CaWs are associated with lower TAWSS and higher OSI than mild atherosclerosis or healthy carotid bifurcation."

STUDY TYPE

Prospective study.

POPULATION

A total of 35 subjects (N = 14 bifurcations with CaW, 11F, age: 49 ± 10, 10 mild atherosclerosis 6F, age: 72 ± 9, 11 healthy 9F, age: 42 ± 13).

FIELD STRENGTH/SEQUENCE

4D flow/STAR-MATCH/3D TOF/3T MRI, CTA.

ASSESSMENT

4D Flow velocity data were analyzed in two ways: 1) 3D ROI in the ICA bulbar segment (complex flow patterns are expected) was used to quantify the regions with low TAWSS and high OSI. 2) 2D planes were placed perpendicular to the centerline of the carotid bifurcation for detailed analysis of TAWSS and OSI.

STATISTICAL TESTS

Independent-samples Kruskal-Wallis-H test with 0.05 used for statistical significance.

RESULTS

The percent surface area where low TAWSS was present in the ICA bulb was 12.3 ± 8.0% (95% CI: 7.6-16.9) in CaW subjects, 1.6 ± 1.9% (95% CI: 0.2-2.9) in atherosclerosis, and 8.5 ± 7.7% (95% CI: 3.6-13.4) in healthy subjects, all differences were statistically significant (ƞ2 = 0.3 [95% CI: 0.05-0.5], P-value CaW vs. healthy = 0.2). OSI had similar values in the CCA between groups (ƞ2 = 0.07 [95% CI: 0.0-0.2], P-value = 0.5), but OSI was significantly higher downstream of the bifurcation in CaW subjects compared to atherosclerosis and normal subjects. OSI returned to similar values between groups 1.5 diameters distal to the bifurcation (ƞ2 = 0.03 [95% CI: 0.0-0.2], P-value = 0.7).

CONCLUSION

Lower TAWSS and higher OSI are present in the ICA bulb in patients with CaW when compared to patients with atherosclerotic or healthy subjects.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

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 stenosis and cryptogenic stroke

OBJECTIVES

Cryptogenic stroke represents a type of ischemic stroke with an unknown origin, presenting a significant challenge in both stroke management and prevention. According to the Trial of Org 10,172 in Acute Stroke Treatment criteria, a stroke is categorized as being caused by large artery atherosclerosis only when there is >50% luminal narrowing of the ipsilateral internal carotid artery. However, nonstenosing carotid artery plaques can be an underlying cause of ischemic stroke. Indeed, emerging evidence documents that some features of plaque vulnerability may act as an independent risk factor, regardless of the degree of stenosis, in precipitating cerebrovascular events. This review, drawing from an array of imaging-based studies, explores the predictive values of carotid imaging modalities in the detection of nonstenosing carotid plaque (<50%), that could be the cause of a cerebrovascular event when some features of vulnerability are present.

METHODS

Google Scholar, Scopus, and PubMed were searched for articles on cryptogenic stroke and those reporting the association between cryptogenic stroke and imaging features of carotid plaque vulnerability.

RESULTS

Despite extensive diagnostic evaluations, the etiology of a considerable proportion of strokes remains undetermined, contributing to the recurrence rate and persistent morbidity in affected individuals. Advances in imaging modalities, such as magnetic resonance imaging, computed tomography scans, and ultrasound examination, facilitate more accurate detection of nonstenosing carotid artery plaque and allow better stratification of stroke risk, leading to a more tailored treatment strategy.

CONCLUSIONS

Early detection of nonstenosing carotid plaque with features of vulnerability through carotid imaging techniques impacts the clinical management of cryptogenic stroke, resulting in refined stroke subtype classification and improved patient management. Additional research is required to validate these findings and recommend the integration of these state-of-the-art imaging methodologies into standard diagnostic protocols to improve stroke management and prevention.

Managing pregnancy-related stroke risk with known bilateral internal carotid artery webs

Carotid webs are intraluminal shelf-like projections caused by thickening of the arterial tunica intima. Due to their projections forming a nidus for thrombus formation and subsequent embolus, they are considered to be a rare cause of ischaemic strokes. We report a case of a woman with a background of recurrent ischaemic strokes due to bilateral carotid webs who presented with a twin pregnancy. We use this case to discuss how her pregnancy-related stroke risk was subsequently medically managed.

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

BACKGROUND

Although carotid web (CaW) is increasingly diagnosed as a cause of cryptogenic stroke, data are still limited to monocentric small sample cohort. To broaden knowledge on symptomatic CaW, CAROWEB registry has been recently implemented.

AIMS

In a large cohort of symptomatic CaW patients, we described epidemiologic characteristics, admission clinical and imaging features, and the current management including the secondary preventive strategy choice made in comprehensive French Stroke Units.

METHODS

CAROWEB is an ongoing French observational multicenter registry enrolling consecutive CaW patients diagnosed after an ipsilateral ischemic stroke (IS) or transient ischemic attack (TIA). Submitted cases were validated by two experienced neurologist and neuroradiologist. Clinical, imaging, and management features were collected for this study.

RESULTS

Between June 2019 and December 2021, 244 cases were submitted by 14 centers, 42 rejected, and 202 included (IS, 91.6%; TIA, 7.9%; retinal infarction, 0.5%; mean age, 50.8 ± 12.2 years; female, 62.9%; Caucasian, 47.5%; Afro-Caribbean, 20.3%). IS patients showed median (interquartile range (IQR)) admission National Institutes of Health Stroke Scale (NIHSS) score, 8 (2-15); intracranial artery occlusion, 71.8%; ipsilateral chronic cerebral infarction (CCI), 16.3%; and reperfusion treatment, 57.3%. CaW was not identified during the mechanical thrombectomy procedure in 30 of 85 (35.3%) patients. Secondary prevention was invasive in 55.6% (stenting, n = 80; surgery, n = 30). In multivariable analysis, the invasive therapeutic option was associated with ipsilateral CCI (odds ratio (OR): 4.24 (1.27-14.2), p = 0.019) and inversely associated with risk factors (OR: 0.47 (0.24-0.91), p = 0.025) and admission NIHSS score (OR: 0.93 (0.89-0.97), p = 0.001).

CONCLUSION

CaW must be considered in all ethnic groups including Caucasians. Secondary prevention is heterogeneous in large French Stroke Centers. The absence of risk factors, milder severity strokes, and ipsilateral CCI were predictive variables of secondary invasive treatment. The high rate of invasive treatment suggests that medical treatment alone is deemed ineffective to avoid recurrence and emphasize the need of randomized trials.

Use of Carotid Web Angioarchitecture for Stroke Risk Assessment

OBJECTIVE

To examine the usefulness of carotid web (CW), carotid bifurcation and their combined angioarchitectural measurements in assessing stroke risk.

METHODS

Anatomic data on the internal carotid artery (ICA), common carotid artery (CCA), and the CW were gathered as part of a retrospective study from symptomatic (stroke) and asymptomatic (nonstroke) patients with CW. We built a model of stroke risk using principal-component analysis, Firth regression trained with 5-fold cross-validation, and heuristic binary cutoffs based on the Minimal Description Length principle.

RESULTS

The study included 22 patients, with a mean age of 55.9 ± 12.8 years; 72.9% were female. Eleven patients experienced an ischemic stroke. The first 2 principal components distinguished between patients with stroke and patients without stroke. The model showed that ICA-pouch tip angle (P = 0.036), CCA-pouch tip angle (P = 0.036), ICA web-pouch angle (P = 0.036), and CCA web-pouch angle (P = 0.036) are the most important features associated with stroke risk. Conversely, CCA and ICA anatomy (diameter and angle) were not found to be risk factors.

CONCLUSIONS

This pilot study shows that using data from computed tomography angiography, carotid bifurcation, and CW angioarchitecture may be used to assess stroke risk, allowing physicians to tailor care for each patient according to risk stratification.

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.

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.

Recurrent stroke shortly after mechanical thrombectomy secondary to carotid web: A case report

RATIONALE

Carotid web, a known source of thrombus for embolic stroke, presents a considerable risk of stroke recurrence. While case reports have demonstrated the safety and effectiveness of mechanical thrombectomy in treating carotid web-related stroke, the need for concurrent carotid artery stenting to prevent recurrent stroke immediately after thrombectomy remains unclear. This study aims to underscore the importance of immediate carotid artery stenting in preventing recurrent stroke following mechanical thrombectomy in patients with carotid web-related stroke.

PATIENT CONCERNS

A 43-year-old woman with acute onset of left limb weakness and slurred speech within 3 hours was admitted to the emergency department.

DIAGNOSES

Computed tomographic angiography confirmed the M1 segment occlusion of the right middle cerebral artery.

INTERVENTIONS

The patient received intravenous thrombolysis in the local hospital and mechanical thrombectomy in our stroke center.

OUTCOMES

Three days post-mechanical thrombectomy, there was a sudden exacerbation of her neurological deficit symptoms. A reexamination via computed tomographic angiography revealed a re-occlusion in M1 segment of the right middle cerebral artery, despite the implementation of stringent anticoagulation therapy for carotid web-related stroke.

LESSONS

Stroke patients with carotid web had a high risk of stroke recurrence and it was necessary to conduct carotid artery stenting to prevent stroke recurrence secondary to the carotid web immediately after mechanical thrombectomy.

Is carotid web an arterial wall dysplasia? A histological series

INTRODUCTION

Described for 60 years under various names, the carotid web is a suspected cause of cryptogenic stroke, especially in young patients. The web creates an intraluminal protrusion that may contribute to turbulent flow and thrombus embolization into cerebral arteries. Although the carotid web has frequently been related to arterial fibrodysplasia, its natural history and pathological description remain unclear.

PATIENTS

Among all consecutive patients admitted to the stroke unit of Sainte-Anne Hospital and referred to the vascular surgery department from January 2015 to December 2022, we retrospectively identified 9 patients with a carotid web. The surgical specimens of the 9 patients were submitted to systematic pathological analysis.

RESULTS

The patients with a histologically confirmed carotid web were young (median age was 42 years), prominently women (7/9), and presenting with low cardiovascular risk. Eight patients had a stroke proven by a magnetic resonance imaging, and 1 had transient monocular amaurosis. The typical pathological lesion supporting the imaging pattern of the carotid web was a focal eccentric intimal hyperplasia forming a protruding lesion characterized by a population of vascular smooth muscle cells intermingled in an abundant, most often loose extracellular matrix. Pathologically proven thrombus was observed in 4 cases. Importantly atherosclerosis was absent.

CONCLUSION

Histological features in our 9 cases strengthen carotid web characterization as a homogeneous pattern of localized intimal hyperplasia. It is a unique entity consistent with intimal fibroplasia, distinct from medial fibromuscular dysplasia and early atherosclerosis.

Optimization of 4D Flow MRI Spatial and Temporal Resolution for Examining Complex Hemodynamics in the Carotid Artery Bifurcation

BACKGROUND

Three-dimensional, ECG-gated, time-resolved, three-directional, velocity-encoded phase-contrast MRI (4D flow MRI) has been applied extensively to measure blood velocity in great vessels but has been much less used in diseased carotid arteries. Carotid artery webs (CaW) are non-inflammatory intraluminal shelf-like projections into the internal carotid artery (ICA) bulb that are associated with complex flow and cryptogenic stroke.

PURPOSE

Optimize 4D flow MRI for measuring the velocity field of complex flow in the carotid artery bifurcation model that contains a CaW.

METHODS

A 3D printed phantom model created from computed tomography angiography (CTA) of a subject with CaW was placed in a pulsatile flow loop within the MRI scanner. 4D Flow MRI images of the phantom were acquired with five different spatial resolutions (0.50-2.00  mm3) and four different temporal resolutions (23-96 ms) and compared to a computational fluid dynamics (CFD) solution of the flow field as a reference. We examined four planes perpendicular to the vessel centerline, one in the common carotid artery (CCA) and three in the internal carotid artery (ICA) where complex flow was expected. At these four planes pixel-by-pixel velocity values, flow, and time average wall shear stress (TAWSS) were compared between 4D flow MRI and CFD.

HYPOTHESIS

An optimized 4D flow MRI protocol will provide a good correlation with CFD velocity and TAWSS values in areas of complex flow within a clinically feasible scan time (~ 10 min).

RESULTS

Spatial resolution affected the velocity values, time average flow, and TAWSS measurements. Qualitatively, a spatial resolution of 0.50  mm3 resulted in higher noise, while a lower spatial resolution of 1.50-2.00  mm3 did not adequately resolve the velocity profile. Isotropic spatial resolutions of 0.50-1.00  mm3 showed no significant difference in total flow compared to CFD. Pixel-by-pixel velocity correlation coefficients between 4D flow MRI and CFD were > 0.75 for 0.50-1.00  mm3 but were < 0.5 for 1.50 and 2.00  mm3. Regional TAWSS values determined from 4D flow MRI were generally lower than CFD and decreased at lower spatial resolutions (larger pixel sizes). TAWSS differences between 4D flow and CFD were not statistically significant at spatial resolutions of 0.50-1.00  mm3 but were different at 1.50 and 2.00 mm3. Differences in temporal resolution only affected the flow values when temporal resolution was > 48.4 ms; temporal resolution did not affect TAWSS values.

CONCLUSION

A spatial resolution of 0.74-1.00  mm3 and a temporal resolution of 23-48 ms (1-2 k-space segments) provides a 4D flow MRI protocol capable of imaging velocity and TAWSS in regions of complex flow within the carotid bifurcation at a clinically acceptable scan time.

The carotid web: Current research status and imaging features

The carotid web is commonly found in the carotid bulb or the beginning of the internal carotid artery. It presents as a thin layer of proliferative intimal tissue originating from the arterial wall and extending into the vessel lumen. A large body of research has proven that the carotid web is a risk factor for ischemic stroke. This review summarizes the current research status of the carotid web and focuses on its imaging presentation.

Comparative analysis between 1-D, 2-D and 3-D carotid web quantification

BACKGROUND

Carotid webs (CaW) are now recognized as a cause of ischemic stroke in young patients. The thromboembolic potential appears related to the CaW's morphology and consequent impact on local flow dynamics. We aim to evaluate the reliability of different measurement methods for the quantification of CaW and their relationship to symptomatic status, presence of large vessel occlusion stroke (LVOS), clot burden and final infarct volume.

METHODS

This was a retrospective analysis of the local comprehensive stroke center CaW database (September 2014-July 2019). CT angiograms (CTAs) were reviewed independently by two raters, blinded to the clinical information and laterality of the stroke/transient ischemic attack. CaW were quantified with 1-D (length), 2-D (area) and 3-D (volume) measurements via Osirix software. Final infarct volume was calculated on MRI. Patients with superimposed CaW thrombus and no repeat imaging were excluded.

RESULTS

Forty-eight CaW (37 symptomatic and 11 contralateral/asymptomatic) in 38 patients were included. Mean age (±SD) was 48.7 (±8.5) years, 78.9% were women and 77.1% were black. Inter-rater agreement was 0.921 (p<0.001) for 1-D, 0.930 (p<0.001) for 2-D, and 0.937 (p<0.001) for 3-D CaW measurements. When comparing symptomatic with asymptomatic CaW, mean web length was 3.2 mm versus 2.5 mm (p<0.02), median area was 5.8 versus 5.0 mm² (p=0.35) and median volume was 15.0 versus 10.6 mm³ (p<0.04), respectively. CaW with a thinner profile (longer intraluminal projection compared with the base) were more likely to be symptomatic (0.67±0.17 vs 0.88±0.37; p=0.01). Average CaW 1-D and final infarct volume had a weak but positive association (Κ=0.230, p<0.05), while no association among web measurements and the presence of LVOS or clot burden was observed.

CONCLUSION

CaW dimension quantification (1-D, 2-D and 3-D) is highly reproducible. Linear and volumetric measurements were more strongly associated with symptoms. The impact of CaW size on the presence of LVOS, clot burden and final infarct volume is unclear.

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.

Recurrent stroke in young adults caused by atypical fibromuscular carotid dysplasia

Background

Carotid Web and focal carotid diaphragm are atypical fibromuscular dysplasia. The bilateral stroke due to this dysplasia is extremely rare. We will report a series of three young patients, admitted for a bilateral ischemic stroke caused by carotid bulb web and internal carotid diaphragm. Also, we will discuss their manifestations and treatment modalities.

Case presentations

In our study, we will report a series of three North African patients, two females an one male, at the mean age of 37, admitted for an ischemic stroke caused by bilateral carotid bulb web and bilateral internal carotid diaphragm.All of our patients were young and didn't have a history of drug use.

Conclusions

In our series, only end-vascular treatment was performed which was necessary to prevent any recurrence. Antiplatelet therapy was used in all cases to prevent any stroke during the follow-up.

Ultrasound characteristics of carotid web

BACKGROUND AND PURPOSE

Carotid web (CaW) is a cause of recurrent ischemic stroke that remains underdiagnosed using Duplex ultrasound (DUS). Improved methods and description of its ultrasound's features could allow better detection of CaW. Ultrasound microflow imaging (MFI) is a blood flow imaging technique sensitive to slow flow that could increase CaW detection. This study aimed to describe ultrasound features of CaW using B-mode imaging and MFI.

METHODS

In a retrospective monocentric study, patients with CaW on CT angiography who underwent DUS examination of carotid arteries were included. DUS was performed by two nonblinded experienced neurosonologists. The specificity of CaW ultrasound features was evaluated using a group of patients with carotid atherosclerotic plaque (AP).

RESULTS

Twenty-four patients with CaW were included. Mean age (standard deviation) was 48 years (11). Seventeen (71%) were females. Fifteen (63%) CaWs were symptomatic. MFI was available for 22 patients. B-mode imaging demonstrated the characteristic CaW appearance in 19/24 (79%) patients as a protruding triangular iso-hypoechoic lesion on longitudinal view. CaW were detected on axial view in only 9/24 (38%) patients. MFI displayed slow blood flow above CaW during systole and allowed it delineation, appearing as a thin triangular endoluminal defect in 18/22 (82%) cases. Based on MFI and B-mode, 21/22 (95%) CaWs were visible, including three CaWs only with MFI. These ultrasound features were not found among 24 patients with AP.

CONCLUSION

We report the ultrasound features from a series of 24 CaW. The use of MFI in addition to B-mode imaging improved the detection rate of CaW.

The carotid diaphragm, an often overlooked cause of stroke by cardiologists

Carotid diaphragm is a rare cause of stroke. Because of its rarity, it remains often undiagnosed. We report the case of four patients who presented a stroke due to carotid diaphragm. The diagnosis was made either by ultrasound Doppler, computed tomography-angiography or angiography. Two of the four patients were managed by carotid stenting and the other two by surgery. The follow-up was normal. Carotid diaphragm stroke is associated with a high risk of recurrence if not well managed. Therefore, the knowledge of this rare entity is necessary.

Carotid web: the challenging diagnosis of an under-recognized entity

BACKGROUND

Determining the cause of acute ischemic stroke is crucial for patient management, particularly for preventing future stroke. In recent years, carotid web (CW), a non-atherosclerotic disorder of the carotid wall, has been found to be an underestimated source of cerebral emboli.

OBJECTIVE

The present study aimed to analyze the clinical, radiological, and pathological findings, along with the treatments performed in patients with CW and ipsilateral ischemic events.

METHODS

Patients with anterior circulation ischemic stroke or transient ischemic attack and ipsilateral CW were prospectively included from January 2019 to December 2021.

RESULTS

Nine patients were enrolled. The median age was 55 (43-62) years, with a female-to-male ratio of 3.5:1. Of the total, seven patients (78%) consulted for recurrent ipsilateral ischemic events. Despite medical treatment, 44% of the patients experienced new episodes. Computed tomographic angiography was suggestive of CW in all cases in which it was performed. The interval between the first ischemic event and diagnosis of CW was of 13 (6-68) months. After ruling out any other possible etiology, every patient underwent carotid revascularization, one underwent stenting and eight underwent carotidectomy. No severe or long-term complications were noted. Histological studies confirmed the diagnosis of CW. There were no recurrences after carotid revascularization during a follow-up of 24 (13-35) months.

CONCLUSION

Knowledge of CW and differentiating it from atheroma plaques is essential, as medical management seems to be insufficient in many cases. Revascularization, which has been shown to be safe and effective, might be the best treatment modality.

Web Browsing: High-Speed Diagnosis and Treatment of Carotid Artery Web

Background: Although carotid artery web (CaW) was initially described in 1973 as a potential etiology of ischemic stroke, it still remains underrecognized. Because CaW is a membrane affixed perpendicularly from the carotid wall that projects out into the lumen above the bifurcation, it typically is not stenotic, and hence, utilizing only 1 vessel imaging modality during conventional stroke workup may instead lead to a diagnosis of ESUS: embolic stroke of undetermined source. The term ESUS was created in 2014 by researchers to define a subset of cryptogenic, nonlacunar (embolic-appearing) strokes without clear cardiac or vascular cause. Purpose: In this review, we describe how, after multiple evaluations of vessels, CaW was diagnosed in relatively young patients (age 39-47 years old, without significant vascular risk factors) in whom otherwise were considered embolic stroke of undetermined source. This observation dovetails with the accompanying  Neurohospitalist article entitled, “Delayed Thrombus Formation on Carotid Web and Its Medical and Endovascular Management for Secondary Stroke Prevention.” Research Design: Not applicable. Case review. Results/Conclusion: This report demonstrates the futility of antiplatelet therapy for a young patient with CaW-related stroke. Based on these collective experiences and review of the literature, we postulate that: (1) multiple vascular imaging modalities during stroke workup may result in a CaW diagnosis instead of ESUS; (2) young stroke patients without traditional vascular risk factors are candidates for this “web browsing” of extended imaging of vessels; and (3) carotid artery stenting (CAS) or carotid endarterectomy (CEA) may be preferred as first-line over medical therapy alone (ie, antiplatelet or anticoagulation) because CEA/CAS addresses the stroke etiology, CaW, definitively.

Evolution of Extracranial Internal Carotid Artery Disease in Children With Sickle Cell Anemia

BACKGROUND

Cerebral arteriopathy in patients with sickle cell anemia mainly affects the intracranial anterior circulation. However, the extracranial internal carotid artery (eICA) can also be stenosed and responsible for ischemic lesions. In children with sickle cell anemia, we perform routine annual Doppler ultrasound assessment of the eICA and magnetic resonance imaging with 3-dimensional time-of-flight magnetic resonance angiography of the Willis circle and neck arteries in those with abnormal velocity. Our aim was to report the evolution of eICA stenoses from 2011 to the present as a function of therapy in a retrospective case-series study. We hypothesized that chronic transfusion (CTT) would be more effective than hydroxyurea and simple observation on the evolution of eICA stenosis.

METHODS

Eligibility criteria were a history of eICA velocity ≥160 cm/s with a minimum Doppler and magnetic resonance imaging follow-up of 1 year. eICAs were graded for stenosis according to NASCET (The North American Symptomatic Carotid Endarterectomy Trial). Magnetic resonance imaging was investigated for ischemic lesions. Treatment with hydroxyurea and CTT were obtained from the chart review.

RESULTS

Fifty-four patients were included. Eight patients had a stroke history. The median (range) follow-up was 4.7 years (1.1-9.2 years). On the first neck magnetic resonance angiography, stenosis was present in 48/54 (89%) patients. Kinking was found in 39/54 (72%) patients. On the last neck magnetic resonance angiography, the proportion of patients with eICA stenosis decreased to 39/54 (72%). ICA occlusion occurred in 5 patients despite CTT. Three patients had carotid webs without intracranial stenosis. The proportion of patients with improvement in stenosis score was 8% with no treatment intensification, 20% with hydroxyurea, and 48% with CTT (P=0.016). The mean (SD) change per year in stenosis score was 0.40 (0.60) without intensification, 0.20 (0.53) with hydroxyurea, and -0.18 (0.55) with CTT (P=0.006). Ischemic lesions were present initially in 46% of patients, and the incidence of progressive ischemic lesions was 2.5 events/100 patient-years. Cox regression analysis showed that the initial score for eICA stenosis was a significant predictive factor for the risk of new silent cerebral infarct events.

CONCLUSIONS

Our study reinforces the need to assess cervical arteries for better prevention of cerebral ischemia and encourage initiation of CTT in sickle cell anemia children with eICA stenosis.

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.

A case of carotid web: Cause of stroke in healthy and young patients

Carotid webs are important, often undiagnosed causes of cryptogenic and recurrent strokes. CT angiography and digital subtraction angiography adequately demonstrate webs as linear filling defects in the carotid bulb. However, findings are overlooked unless viewed in optimal planes and easily misdiagnosed as dissection flaps or atheromatous plaques, altering management and outcome. A case of unilateral carotid web is presented, detected during imaging in a young lady presenting with hemiparesis without other risk factors for stroke.

Carotid Web Phenotype Is Uncommonly Associated With Classic Fibromuscular Dysplasia: A Retrospective Observational Study

BACKGROUND AND PURPOSE

Carotid web (CaW) is an intimal form of fibromuscular dysplasia (FMD) involving the carotid bulb which has been increasingly recognized as a potential cause of recurrent ischemic strokes. It is overlooked as a separate entity and often dismissed if no coexistent signs of classic FMD changes are observed. We aim to evaluate the frequency of classic FMD in high-yield vascular territories in patients with symptomatic CaW.

METHODS

This was a retrospective analysis of a symptomatic CaW database of 2 comprehensive stroke centers (spanning September 2014-October 2020). The diagnosis of a CaW during a stroke workup was defined as the presence of a shelf-like linear filling defect in the posterior aspect of the carotid bulb on computed tomography angiography in patients with acute ischemic stroke or transient ischemic attack of undetermined cause after a thorough evaluation. Neck computed tomography angiography and renal conventional angiography images were independently evaluated by two readers blinded to the laterality and clinical details to inspect the presence of underlying classic FMD.

RESULTS

Sixty-six patients with CaW were identified. Median age was 51 years (interquartile range, 42-57), and 74% were women. All patients had neck computed tomography angiography (allowing for bilateral vertebral and carotid evaluation), whereas 47 patients had additional digital subtraction angiography (which evaluated 47 carotids ipsilateral to the stroke and 10 contralateral carotids). Internal carotid artery classic FMD changes were noted in only 6 out of 66 (9%) in the ipsilateral carotids. No contralateral carotid or vertebral artery classic FMD changes were observed. Renal artery catheter-based angiography was obtained in 16 patients/32 arteries and only 1 patient/2 renal arteries demonstrated classic FMD changes.

CONCLUSIONS

CaW phenotype is uncommonly associated with classic FMD changes. Coexistent classic FMD does not constitute a useful marker to corroborate or exclude CaW diagnosis.

Delayed Thrombus on Carotid Web: Case Report With Escalation of Treatment

Carotid artery web is an underrecognized source and is found in about 1-2% of patients with acute ischemic stroke. Although, first described four decades ago, optimal therapy for carotid web is not yet known. Carotid stenting and endarterectomy are increasingly used for carotid web treatment, given its definitive treatment and avoiding the complications associated with anticoagulation. The case reported here is of an ischemic stroke secondary to a mobile thrombus on a carotid web evident on CT angiography and successful definitive treatment with delayed carotid wall stent placement. In young patients who have a diagnosis of ischemic stroke, the carotid web should be on the differential and adequate neuroimaging with either CTA or DSA should be pursued.

Assessment of association between the carotid web and dissection in spontaneous internal carotid artery dissection patients using vessel wall MRI

BACKGROUND

Internal carotid artery dissection (ICAD) is the major cause of ischemic stroke in young to middle-aged people. Recognition of predisposing factors may facilitate in early individual risk prediction and expand treatment.

PURPOSE

To evaluate the association between a carotid web and dissection in patients with ICAD using vessel wall magnetic resonance imaging (VW-MRI).

MATERIAL AND METHODS

A retrospective study was conducted of 223 patients who underwent VW-MRI. Of these patients, 58 patients with craniocervical artery dissection (CCAD) (33 ICAD and 25 vertebrobasilar artery dissection [VBAD]) were included. The control group (n = 165) consisted of patients without arterial dissection who had undergone VW-MRI . The presence of a carotid web in the posterior aspect of carotid bulb was recorded. The distance between the carotid web and start of dissection in ICA was recorded.

RESULTS

The presence of a carotid web showed a significant difference between the ICAD, VBAD, and control groups (19 [57.6%] vs. 5 [20%] vs. 36 [21.8%], respectively; P < 0.001). In multi-nominal analysis, the presence of a carotid web showed a significant difference between the ICAD and VBAD groups and the ICAD and control groups (P < 0.05), with odds ratios of 5.41 (95% confidence interval [CI]=1.634-17.973) and 4.81 (95% CI=2.176-10.651), respectively. Out of 19 ICAD patients with carotid web, 16 had occurrence of dissection in the C1 segment of the ICA with a mean distance of 1.91 ± 1.71 cm from the carotid web.

CONCLUSION

Presence of a carotid web was more frequent in patients with ICAD. The carotid web may be one of the predisposing factors for development of dissection in patients with ICAD.

Embolectomy of acute embolic stroke associated with ipsilateral carotid web: a case report and literature review

A carotid web is a thin intraluminal protrusion located in the posterolateral wall of the carotid bulb, which might be a risk factor for cryptogenic stroke. The mechanism of ischemic stroke caused by carotid web is still unclear, but it might be related to hemodynamic changes distal to the web, resulting in flow forces and remote embolization of fibrin-based clots. The diagnosis of a carotid web mainly depends on carotid artery imaging examinations. The main therapeutic strategies include medical treatment with oral antiplatelet agents and anticoagulants, and operative treatment, such as carotid endarterectomy and carotid artery stenting. Few cases of acute large-vessel occlusion undergoing mechanical thrombectomy in the setting of carotid web as the etiology have been reported. We report here a case of a 37-year-old woman who underwent stent retriever embolectomy after acute ischemic stroke. Carotid artery imaging examinations, including digital subtraction angiography and magnetic resonance imaging, and pathology showed that a carotid web was located at the proximal right internal carotid artery. We also discuss the clinical pathophysiological and imaging features, and the treatment of carotid web as described in the currently available literature.

Prevalence and site of predilection of carotid webs focusing on symptomatic and asymptomatic Japanese patients

OBJECTIVE

Carotid webs (CWs) have increasingly been recognized as a cause of recurrent ischemic stroke. However, the natural history and clinical course of CWs remain unclear. The authors aimed to clarify the prevalence, imaging features, and optimal treatment of CWs in a Japanese cohort study.

METHODS

A series of 444 consecutive Japanese patients who had undergone CTA of the head and neck between April 2011 and October 2016 was retrospectively reviewed. CW was diagnosed on CT angiograms as a membrane-like intraluminal filling defect along the posterior wall of the carotid bulb or the origin of the internal carotid artery (ICA) on oblique sagittal images and a corresponding thin septum on axial images.

RESULTS

Two patients with CWs were identified among 132 patients with suspected stroke. The prevalence of CWs among symptomatic patients with suspected stroke was 1.5%. The prevalence of asymptomatic CWs was 2.2% (7 of 312 cases). The CWs were located in the posterior wall of the carotid bulb in 7 patients and just distal to the ICA origin in 2 patients. There were no apparent differences in the location or lesion length between symptomatic and asymptomatic CWs. Four of the 7 asymptomatic CWs remained asymptomatic for at least 2 years of follow-up. Two patients with symptomatic CWs developed recurrent cerebral infarction and transient ischemic attack despite being on a regimen of oral antiplatelet agents, and carotid endarterectomy was performed as radical treatment. Patients with CWs were younger than controls (median age 55 vs 69 years, p = 0.003) and were less frequently male than controls (33% vs 72%, p = 0.025). CW cases showed significantly fewer common atherosclerosis risk factors than the control group (p < 0.05).

CONCLUSIONS

Although limited to CTA patients, this study reported on the prevalence and common site of CWs, focusing on symptomatic and asymptomatic Japanese patients. Extensive cross-sectional and prospective observational studies are warranted to elucidate the overall prevalence and natural history of CWs.

Imaging and clinical features of cervical artery web: report of 41 cases and literature review

This study investigated the imaging and clinical features of cervical artery web to improve disease diagnosis. Imaging and clinical data of 41 patients with cervical artery web were retrospectively analyzed and summarized in the context of the literature. Of the 8653 patients who underwent carotid computed tomography angiography (CTA) in the past 3 years at our hospital, 41 (0.47%) were diagnosed with cervical artery web. Among the 41 patients, there were 38 web structures in typical position, including 26 web structures located in the internal carotid artery and 12 in the proximal bifurcation of the common carotid artery. And the other three web structures were located outside carotid artery, including two in the subclavian artery and one in the vertebral artery. There were 47 web structures in 41 cases of cervical artery web; 35/41 (85.3%) were unilateral and 6/41 (14.7%) were bilateral. Among 41 patients, there were 20 patients who had cerebral infarction, 14 who experienced transient ischemic attack, 3 patients with cerebral hemorrhage; and 4 with other manifestations. Cervical artery web showed typical imaging features in the carotid CTA. Cervical artery web was most common in the internal carotid artery and at the bifurcation of the common carotid artery. It was also occasionally found in other rare artery such as vertebral and subclavian artery. Based on the various locations of web structure, we think it is necessary to rename carotid web as cervical artery web. Most of the attachment sites of the web structures were located in the posterior wall of the lumen, followed by the lateral wall; sites on the anterior wall were rare. Cervical artery web may be an underappreciated risk factor for stroke. And hypertension can increase the incidence of ischemic stroke in patients with cervical artery web.

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.

Carotid webs produce greater hemodynamic disturbances than atherosclerotic disease: a DSA time-density curve study

Background

Carotid webs (CaWs) are associated with ischemic strokes in younger patients without degrees of stenosis that are traditionally considered clinically significant.

Objective

To compare the hemodynamic parameters in the internal carotid artery (ICA) bulbar segment in patients with CaW with those in patients with atherosclerotic lesions using time–density curve (TDC) analysis of digital subtraction angiography (DSA) images.

Methods

We retrospectively assessed DSA images of 47 carotid arteries in 41 adult patients who underwent ICA catheter angiography for evaluation after ischemic stroke. Hemodynamic parameters, including full width at half maximum (FWHM) and area under the time–density curve (AUC) as proxies for increased flow stasis, were calculated using TDC analyses of a region of interest (ROI) in the ICA bulb immediately rostral to the web/atherosclerotic plaque, relative to a standardized ROI in the ipsilateral distal common carotid artery (eg, relative FWHM (rFWHM)). Hemodynamic parameters were compared using non-parametric Kruskal-Wallis tests. Logistic regression was used to predict CaW versus mild/moderate atherosclerosis for each hemodynamic parameter, adjusting for degree of stenosis.

Results

Mean age of patients was 56.0±13 years, with 22 (53.7%) women. 17 CaWs, 22 atherosclerotic plaques (15 mild/moderate and 7 severe), and eight normal carotid arteries were assessed. Significant between-group differences were present in the relative total AUC (p<0.001), relative AUC at wash out (p=0.031), and relative FWHM (p=0.001). Logistic regression to predict CaW versus mild/moderate atherosclerosis showed that rAUC total had the highest predictive value (pAUC=0.96, 95% CI 0.90 to 1.00), followed by rFWHM (0.87, 95% CI 0.74 to 1.00), and rAUC WO (0.74, 95% CI (0.57 to 0.91).

Conclusion

CaW results in larger local hemodynamic disruption, characterized by flow stasis, than mild/moderate carotid atherosclerotic lesions, suggesting that CaWs may produce larger regions of thrombogenic flow stasis.

Turbulence Intensity as an Indicator for Ischemic Stroke in the Carotid Web

OBJECTIVE

Carotid web (CaW) is reported as one of the causes of cryptogenic strokes. However, its pathophysiology is not known, which makes clinicians debate CaW treatment. The current study presents the mechanism of ischemic stroke in CaW and finds a potential indicator for ischemic stroke in CaW.

METHODS

Computational fluid dynamics (CFD) was applied to computer-aided artificial human CaW models to investigate the correlation between stenosis rate and CaW angle. The CFD results were compared with stroke or symptomatic CaW including adequate reported images for anatomic analysis of the stenosis rate and CaW angle.

RESULTS

The CFD result of the CaW models shows that the velocity decreases and the turbulence generation of blood flow increases in the area under CaW (AuCaW). In AuCaW, turbulence intensity (TI) is high in the high stenosis rate and small angle conditions. Moreover, TI remained high in the AuCaW throughout the cardiac cycles. The analysis of 67 anatomic figures appeared in 36 articles merged with CFD results, and a CaW scoring system was introduced for clinicians to determine patients with CaW with a high risk of ischemic stroke.

CONCLUSIONS

This study is believed to be the first to apply TI to CaW. Because most ischemic strokes in CaW occurred at a high stenosis rate and small angle, TI may be used as a potential indicator of ischemic stroke in CaW. Furthermore, TI is easily used in the daily clinical field by applying CaW scores.

Endarterectomy for symptomatic internal carotid artery web

OBJECTIVE

The carotid web (CW) is an underrecognized source of cryptogenic, embolic stroke in patients younger than 55 years of age, with up to 37% of these patients found to have CW on angiography. Currently, there are little data detailing the best treatment practices to reduce the risk of recurrent stroke in these patients. The authors describe their institutional surgical experience with patients treated via carotid endarterectomy (CEA) for a symptomatic internal carotid artery web.

METHODS

A retrospective, observational cohort study was performed including all patients presenting to the authors' institution with CW. All patients who were screened underwent either carotid artery stenting (CAS) or CEA after presentation with ischemic stroke from January 2019 to February 2020. From this sample, patients with suggestive radiological features and pathologically confirmed CW who underwent CEA were identified. Patient demographics, medical histories, radiological images, surgical results, and clinical outcomes were collected and described using descriptive statistics.

RESULTS

A total of 45 patients with symptomatic carotid lesions were treated at the authors' institution during the time period. Twenty patients underwent CAS, 1 of them for a CW. Twenty-five patients were treated via CEA, and of these, 6 presented with ischemic strokes ipsilateral to CWs, including 3 patients who presented with recurrent strokes. The mean patient age was 55 ± 12.6 years and 5 of 6 were women. CT angiography or digital subtraction angiography demonstrated the presence of CWs ipsilateral to the stroke in all patients. All patients underwent resection of CWs using CEA. There were no permanent procedural complications and no patients had stroke recurrence following intervention at the latest follow-up (mean 6.1 ± 4 months). One patient developed mild tongue deviation most likely related to retraction, with complete recovery at follow-up.

CONCLUSIONS

CEA is a safe and feasible treatment for symptomatic carotid webs and should be considered a viable alternative to CAS in this patient 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 webs in large vessel occlusion stroke: Clinical, radiological and thrombus histopathological findings

BACKGROUND

Carotid webs are an under-recognized embolic source in patients with cryptogenic stroke. Limited resources currently exist to assist clinicians in stroke prevention for patients with symptomatic carotid webs (SCW). We aimed at analysing the clinical, radiological and procedural features of stroke patients with SCW undergoing endovascular thrombectomy (EVT), and to describe the histopathological composition of their occlusive thrombi.

METHODS

In a single-center observational study on consecutive patients with ischemic stroke treated by EVT, carotid web was defined symptomatic when it was ipsilateral to the ischemic lesion in a patient classified with stroke of otherwise undetermined etiology. Clinical, radiological and procedural data of patients with SCW were evaluated. Histopathological examination of the retrieved thrombi was performed.

RESULTS

Out of 1430 patients with large vessel occlusion stroke treated by EVT, 11(0.7%) were found to have a SCW. Patients with SCW had a median age of 47 years old (IQR 38-50), they were prevalently women (55%), mostly of African ethnicity (91%). Each of the 11 patients achieved successful angiographic reperfusion (mTICI 2b-3) after EVT. For secondary prevention, elective endovascular carotid stenting was performed in 5 (55%) patients, while 1 (9%) was treated by surgical endoarterectomy. Histological analysis of the retrieved thrombi performed in 4 patients showed a mixed composition with variable red blood cell content.

CONCLUSIONS

EVT is feasible in large vessel occlusion stroke related to SCW. Procedures of carotid revascularization appear to be feasible therapeutic options for secondary prevention. The histopathological analysis of cerebral thrombi may provide new insights on stroke pathogenesis in patients with SCW.

How I do it: endarterectomy for carotid web

BACKGROUND

The carotid web is an important and under recognized etiology for recurrent cryptogenic strokes. A management option for a symptomatic carotid web is a carotid endarterectomy (CEA) with surgical microdissection and removal of the intimal luminal defect.

METHODS

We describe some of the technical nuances involved in successfully performing a carotid endarterectomy for resection of a carotid web.

CONCLUSION

Utilizing a familiar approach to an understudied pathology, this procedure can be safely performed and provides the patient with lasting protection against recurrent infarcts through removal of the thromboembolic nidus.

Stroke Recurrence in First-Ever Symptomatic Carotid Web: A Cohort Study

Background and Purpose

Carotid web (CaW) is an intimal variant of fibromuscular dysplasia responsible for ipsilateral cerebral ischemic events (CIE). Symptomatic CaW likely has a high risk of recurrent CIE, but no salient prospective data are available. We aimed to assess recurrence rate and its predictors after a first-ever CIE.

Methods

Consecutive Afro-Caribbean patients who had cryptogenic first-ever CIEs (ischemic stroke [IS] or transient ischemic attack [TIA]) associated with ipsilateral CaW were included in this multicenter observational cohort study. The follow-up (January 2008 to March 2019) focused on CIE recurrences. Kaplan-Meier method assessed rates of recurrences and Cox proportional hazards regression analyzed risk factors.

Results

Ninety-two patients (79 first-ever ISs and 13 TIAs; mean age±standard deviation, 49.8±9.9 years; 52 [56.5%] women) were included. During a mean follow-up of 50.5±29.6 months, 19 (20.7%) patients experienced recurrent ipsilateral CIEs (16 ISs and three TIAs). Of 23 patients receiving surgery/stenting treatment, no recurrence occurred after the intervention (median follow-up, 39.8 months [interquartile range, 27.6 to 72.4]). Under medical treatment alone, the annual recurrent CIE rate was 6.9%, and the cumulative rate was 4.4% at 30-day, 10.8% at 1-year, 19.8% at 2-year, 23.2% at 3-year, and 27.3% at 5-year. Presence of silent cerebral infarctions was the only independent risk factor of CIE recurrences (hazard ratio, 6.99; 95% confidence interval, 2.4 to 20.4; P=0.004).

Conclusions

Under medical treatment alone, symptomatic CaW was associated with a high rate of recurrence that reached 27.3% at 5-year. Surgery/stenting seems to be efficient, and randomized control trials are required to confirm the benefit of these interventions.

Prevalence of carotid web in a French cohort of cryptogenic stroke

BACKGROUND AND PURPOSE

Carotid webs (CaW) may be an under-recognized cause of anterior circulation cryptogenic ischemic stroke (ACIS). Prevalence is still unknown in European patients with ACIS.

OBJECTIVE

To evaluate the prevalence of CaW in ACIS and describe patients with CaW phenotype in a cohort of patients from a French stroke center.

METHODS

We conducted a retrospective monocentric cohort study from 01/01/2015 to 31/12/2019 (Montpellier University Hospital, France), in consecutive anterior ischemic stroke (AIS) patients ≤65 years old from a prospective stroke database. Using ASCOD phenotyping, ACIS patients were selected and cervical CTA were reviewed to find CaW.

RESULTS

Among 1053 consecutive AIS patients, 266 ACIS patients with CTA were included. Among patients included (mean age 50, women 58%), CaW was in the ipsilateral carotid (iCaW) in 21 patients: 7.9% (95%CI [4.6-11.1]), (mean age 51, 11 women, 16 Caucasian). iCaW were uncovered during study review of CTA in 6/21 (29%) patients. Comparison between patients with iCaW and those without iCaW showed no differences except that of a higher rate of intracranial large vessel occlusion (LVO) (62.4 vs 37.6%; p = 0.03). Patients with iCaW under conservative medical therapy had an annualized stroke recurrence rate (SRR) of 11.4% (95%CI [8.4-15.1].

CONCLUSIONS

iCaW was identified as a source of stroke in about 8% of a French population ≤65 years with ACIS. iCaW was associated with a higher rate of LVO and a high SRR under conservative medical therapy.

Baseline Characteristics of Patients with Symptomatic Carotid Webs: A Matched Case Control Study

BACKGROUND AND PURPOSE

The baseline characteristics of patients with symptomatic carotid web (CaW) are unclear. We investigate demographic and cerebrovascular risk factors in patients with this overlooked stroke etiology.

METHODS

We identified consecutive patients diagnosed with symptomatic CaW at a comprehensive stroke center from July 2014-December 2018. These patients were matched at a 1:4 ratio (based on age and NIHSS scores) to create a control group of acute ischemic stroke (AIS) patients with non-CaW etiologies from the local GetWithTheGuidelines stroke database.

RESULTS

Thirty patients with symptomatic CaW were compared to 120 AIS patients with non-CaW etiologies. Symptomatic CaW patients were more likely to be female (73.3 vs. 44.2%; p = 0.004) and black (86.7 vs. 64.2%; p = 0.02). Symptomatic CaWs patients had a fewer absolute number of modifiable cerebrovascular risk factors (1.7±1.1 vs. 2.5±1.2; p = 0.002), lower rates of hypertension (43.4 vs. 63.3%; p = 0.04), and a more favorable lipid profile with lower average LDL (89.5±30.3 vs. 111.2±43.7 mg/dL; p = 0.01) and higher average HDL (47.9±11.3 vs. 42.2±13.8 mg/dL; p = 0.01) as compared to strokes with non-CaW etiology. Symptomatic CaW patients were more likely to have a large vessel occlusion (80.0 vs. 51.7%; p = 0.005), despite similar e-ASPECTS between the groups (8.1±2.1 vs. 8.3±2.2; p = 0.30). On multivariable analysis, symptomatic CaW was an independent predictor of independence at discharge (OR 3.72; 95%CI 1.27-10.94).

CONCLUSION

A gender and racial predilection of symptomatic CaWs may exist as females and blacks were were found to be more likely affected. Symptomatic CaW patients have a more benign cerebrovascular risk factor profile corroborating the proposed mechanism of local stasis and thromboembolism. Despite presenting more commonly with LVO, symptomatic CaW was associated with good functional outcome, warranting further studies.

Prevalence of Cervical Artery Abnormalities on CTA in Patients with Spontaneous Coronary Artery Dissection: Fibromuscular Dysplasia, Dissection, Aneurysm, and Tortuosity

BACKGROUND AND PURPOSE

Little is known about associations between spontaneous coronary artery dissection and cervical artery abnormalities. This study sought to assess the prevalence of cervical artery abnormalities among patients with spontaneous coronary artery dissection.

MATERIALS AND METHODS

A retrospective analysis was completed of patients who underwent CTA neck imaging as part of arterial assessment following the diagnosis of spontaneous coronary artery dissection. The internal carotid and vertebral arteries were evaluated for the presence of fibromuscular dysplasia, dissection and/or pseudoaneurysm, ectasia and/or aneurysmal dilation, atherosclerosis, and webs. Carotid tortuosity was categorized into kinks, loops, coils, and retrojugular and/or retropharyngeal carotid courses; vertebral tortuosity was classified by subjective analysis of severity.

RESULTS

Two hundred fourteen patients were included in the final cohort, of whom 205 (95.8%) were women; the average age was 54.4 years. Fibromuscular dysplasia was the most frequently observed abnormality (83 patients; 38.8%), followed by dissections and/or pseudoaneurysms (n = 28; 13.1%), ectasia and/or aneurysmal dilation (n = 22; 10.3%), and carotid webs (n = 10; 4.7%). At least 1 type of carotid tortuosity was present in 99 patients (46.3%). The majority (n = 185; 86.4%) of patients had no carotid atherosclerosis; and 26 (12.2%) had mild; 3 (1.4%), moderate; and 0, severe carotid atherosclerosis.

CONCLUSIONS

The most common abnormality in the cervical artery vasculature of patients with spontaneous coronary artery dissection is fibromuscular dysplasia. Cervical dissections were higher than previously reported but were not observed in most patients.