Endarterectomy for symptomatic non-stenotic carotids: a systematic review and descriptive analysis

Imaging of non-stenotic carotid plaque for embolic stroke of undetermined source

PURPOSE

Ischemic stroke is a significant cause of death and disability. Embolic Stroke of Undetermined Source (ESUS) accounts for a large proportion of acute ischemic strokes. A clear etiology is crucial for the treatment and prevention of stroke. The pathogenic mechanism of non-stenotic carotid plaque (NSCP) in ESUS is not yet fully understood. This study used computed tomographic angiography (CTA) to assess the correlation between NSCP and ESUS.

METHOD

Eighty-one patients with unilateral anterior circulation ESUS were retrospectively enrolled between June 2020 and June 2022. The prevalence of NSCP, degree of stenosis, plaque thickness, plaque type, plaque irregularity, plaque ulceration, focal areas of hypodensity within the plaque, and positive remodeling were evaluated in both carotid arteries on CTA. Univariate and multivariate logistic regression were used to determine the relationship between NSCP, plaque characteristics, and ipsilateral stroke.

RESULTS

Among 81 patients with unilateral anterior circulation ESUS, the incidence of NCSP was significantly higher in the ipsilateral carotid artery than in the contralateral side (76.5 % vs. 60.5 %, P = 0.028). Plaque type, plaque thickness, plaque thickness >3 mm, and focal areas of hypodensity within the plaque were remarkably different between two sides of carotid plaques (all P < 0.05). In addition, multifactorial logistic regression showed that intraplaque hypodensity (aOR = 6.449 [95 % CI, 1.818-22.878]) and greater plaque thickness (aOR = 2.476 [95 % CI, 1.14-5.38]) were significantly associated with ESUS.

CONCLUSIONS

The prevalence of NSCP ipsilateral to stroke is higher in ESUS patients, and more complex plaque features were found on the ipsilateral side. Greater plaque thickness and hypodensity within the plaque were significantly associated with ESUS, and these plaques may be an important embolization source of ESUS.

Stroke risk management in carotid atherosclerotic disease: a clinical consensus statement of the ESC Council on Stroke and the ESC Working Group on Aorta and Peripheral Vascular Diseases

Carotid atherosclerotic disease continues to be an important cause of stroke, often disabling or fatal. Such strokes could be largely prevented through optimal medical therapy and carotid revascularization. Advancements in discovery research and imaging along with evidence from recent pharmacology and interventional clinical trials and registries and the progress in acute stroke management have markedly expanded the knowledge base for clinical decisions in carotid stenosis. Nevertheless, there is variability in carotid-related stroke prevention and management strategies across medical specialities. Optimal patient care can be achieved by (i) establishing a unified knowledge foundation and (ii) fostering multi-specialty collaborative guidelines. The emergent Neuro-Vascular Team concept, mirroring the multi-disciplinary Heart Team, embraces diverse specializations, tailors personalized, stratified medicine approaches to individual patient needs, and integrates innovative imaging and risk-assessment biomarkers. Proposed approach integrates collaboration of multiple specialists central to carotid artery stenosis management such as neurology, stroke medicine, cardiology, angiology, ophthalmology, vascular surgery, endovascular interventions, neuroradiology, and neurosurgery. Moreover, patient education regarding current treatment options, their risks and advantages, is pivotal, promoting patient's active role in clinical care decisions. This enables optimization of interventions ranging from lifestyle modification, carotid revascularization by stenting or endarterectomy, as well as pharmacological management including statins, novel lipid-lowering and antithrombotic strategies, and targeting inflammation and vascular dysfunction. This consensus document provides a harmonized multi-specialty approach to multi-morbidity prevention in carotid stenosis patients, based on comprehensive knowledge review, pinpointing research gaps in an evidence-based medicine approach. It aims to be a foundational tool for inter-disciplinary collaboration and prioritized patient-centric decision-making.

Symptomatic Nonstenotic Carotids: A Topical Review

Historically, the management of carotid artery disease has primarily focused on the degree of stenosis as the main indicator for assessing stroke etiology, risk, and need for intervention. However, accumulating evidence suggests that structural and biological features within the arterial wall, such as intraplaque hemorrhage, may have superior diagnostic, prognostic, and therapeutic values. Under current guidelines, unless an atheroma results in ≥50% stenosis, it is not considered the cause of a cerebrovascular event. This results in extensive and often unproductive diagnostic workup, prescription of ineffective medical therapy, and preclusion of patients from receiving revascularization procedures that have been shown to prevent recurrent cerebrovascular events in cases of ≥50% stenosis. A subset of embolic strokes of undetermined source, which account for up to 25% of all ischemic cerebrovascular events, are thought to be due to thromboembolic phenomena from undiagnosed plaque disruptions in nonstenotic arteries (<50% stenosis). Recently, it has been proposed to reclassify this subgroup of patients as symptomatic nonstenotic carotid if the carotid plaque ipsilateral to the cerebrovascular event presents with high-risk features including intraplaque hemorrhage, lipid-rich necrotic core, thinning/rupture of the fibrous cap, and ulceration. In this review, we first provide a historical overview of the chain of events and circumstances that resulted in the present management of carotid artery disease. Second, we embed the contemporary biomarkers of plaque vulnerability in a modern mechanistic paradigm of carotid plaque disruption and thromboembolization. Third, we review the clinically available imaging tools to detect these biomarkers, and how their use has started to shed light on the prevalence and natural history of this underdiagnosed condition. Fourth, we review recent clinical studies employing a contemporary definition of symptomatic nonstenotic carotid and discuss targeted treatments for this condition. Finally, we make a case to generate the much-needed high-level evidence to align the clinical management of patients with symptomatic nonstenotic carotid with a contemporary understanding of plaque disruption and thromboembolization.

The role of non-stenosing carotid artery plaques in embolic stroke of undetermined source, is it a silent offender? A review of literature

PURPOSE

Atherosclerotic cervical internal carotid artery disease is one of the major causes of ischemic stroke and transient ischemic attacks. The risk of stroke from mild to moderate stenoses (i.e. <50% stenosis) might be underestimated. There is increasing evidence that plaque morphological features reflect plaque instability that may harbor high risk for embolization. In this narrative review, we will review the literature on plaque features that predict vulnerability beyond the degree of stenosis, discuss the clinical association with stroke, and evaluate the evidence that these lesions serve as a source for embolic stroke of unknown source (ESUS).

METHODS

We performed a literature search using PubMed, EMBASE, and Web of Science. The terms "embolic stroke of undetermined source" and "plaque morphology" were used either alone or in combination with "non-flow limiting stenosis," "non-stenosing plaques," "high-risk plaque features" or "internal carotid artery plaque." Data on plaque morphology and ESUS were mainly taken from review articles, observational studies including retrospective cohort and cross-sectional studies, meta-analyses, and systematic reviews.

CONCLUSION

Nonstenosing carotid artery plaques with high-risk features carry a remarkable risk for stroke occurrence and randomized clinical trials are warranted for further evaluation of using carotid artery stenting or carotid endarterectomy to mitigate the risk of stroke.

Carotid Endarterectomy With Shunt-A Stepwise Surgical Technique Demonstration for Trainees: 2-Dimensional Operative Video

Carotid endarterectomy (CEA) is a common cerebrovascular surgery and is an effective treatment option for patients with carotid stenosis. 1-4 Although the routine or selective use of a shunt is still debatable, 5 the CEA technique is generally well-established. We believe that bloodless and “shallow and wide” operative fields make CEA safe and successful. Maintaining a bloodless operative field is highly crucial to prevent postoperative cervical hematoma and damage to anatomic structures, such as the hypoglossal and vagus nerves, because it facilitates their identification. In the cases of CEA, antiplatelet medications are usually continued, and systemic heparinization is performed intraoperatively; therefore, further meticulous hemostasis should be performed than in other neurological surgery cases. The 2-step pull-up technique, which involves pulling up loose connective tissue surrounding the carotid arteries in addition to the carotid sheath, makes the operative field “shallow and wide.” This technique allows the internal carotid artery to move from deep to superficial, making CEA feasible, particularly when placing a shunt. This video illustrates the CEA technique used for symptomatic mild carotid stenosis in a 66-year-old man with vulnerable plaques. Evolving carotid artery stenting should facilitate the improvement of the operative technique to increase the safety and accordingly train young surgeons. This video is intended to increase familiarity with CEA because carotid artery stenting decreases CEA indications for carotid stenosis and diminishes proficiency in managing CEA. The patient consented to the publication of his image. Patient consent was obtained to perform the surgery and publish the surgical video.

Quantifying Carotid Stenosis: History, Current Applications, Limitations, and Potential: How Imaging Is Changing the Scenario

Carotid artery stenosis is a major cause of morbidity and mortality. The journey to understanding carotid disease has developed over time and radiology has a pivotal role in diagnosis, risk stratification and therapeutic management. This paper reviews the history of diagnostic imaging in carotid disease, its evolution towards its current applications in the clinical and research fields, and the potential of new technologies to aid clinicians in identifying the disease and tailoring medical and surgical treatment.

MR Imaging of Carotid Artery Atherosclerosis: Updated Evidence on High-Risk Plaque Features and Emerging Trends

MR imaging is well-established as the criterion standard for carotid artery atherosclerosis imaging. The capability of MR imaging to differentiate numerous plaque components has been demonstrated, including those features that are associated with a high risk of sudden changes, thrombosis, or embolization. The field of carotid plaque MR imaging is constantly evolving, with continued insight into the imaging appearance and implications of various vulnerable plaque characteristics. This article will review the most up-to-date knowledge of these high-risk plaque features on MR imaging and will delve into 2 major emerging topics: the role of vulnerable plaques in cryptogenic strokes and the potential use of MR imaging to modify carotid endarterectomy treatment guidelines.

Nonstenotic Carotid Plaques and Embolic Stroke of Undetermined Source: A Multimodality Review

Symptomatic nonstenotic carotid artery disease has been increasingly recognized as a thromboembolic source in patients who would otherwise be classified as having embolic stroke of undetermined source. Evidence suggests that certain plaque features seen on sonography, CT, and MR imaging in nonstenotic carotid artery disease may predispose to recurrent stroke in patients with embolic stroke of undetermined source. We performed a focused literature review to further study plaque features in the context of embolic stroke of undetermined source and to determine which plaque features may be associated with ipsilateral ischemic events in such patients. Plaque thickness as seen on both ultrasound and CT appears to have a consistent association with ipsilateral stroke in patients with embolic stroke of undetermined source across multiple studies. Intraplaque hemorrhage as seen on MR imaging is now understood to have a strong association with ipsilateral stroke in patients with embolic stroke of undetermined source. Continued study of various plaque features as seen on different modalities is warranted to uncover other potential associations.

Unifying theory of carotid plaque disruption based on structural phenotypes and forces expressed at the lumen/wall interface

OBJECTIVES

To integrate morphological, haemodynamic and mechanical analysis of carotid atheroma driving plaque disruption.

MATERIALS AND METHODS

First, we analysed the phenotypes of carotid endarterectomy specimens in a photographic dataset A, and matched them with the likelihood of preoperative stroke. Second, laser angioscopy was used to further define the phenotypes in intact specimens (dataset B) and benchmark with histology. Third, representative vascular geometries for each structural phenotype were analysed with Computational Fluid Dynamics (CFD), and the mechanical strength of the complicated atheroma to resist penetrating forces was quantified (n=14).

RESULTS

In dataset A (n=345), ulceration (fibrous cap disruption) was observed in 82% of all plaques, intraplaque haemorrhage in 68% (93% subjacent to an ulcer) and false luminal formation in 48%. At least one of these 'rupture' phenotypes was found in 97% of symptomatic patients (n=69) compared with 61% in asymptomatic patients. In dataset B (n=30), laser angioscopy redemonstrated the structural phenotypes with near-perfect agreement with histology. In CFD, haemodynamic stress showed a large pulse magnitude, highest upstream to the point of maximal stenosis and on ulceration the inflow stream excavates the necrotic core cranially and then recirculates into the true lumen. Based on mechanical testing (n=14), the necrotic core is mechanically weak and penetrated by the blood on fibrous cap disruption.

CONCLUSIONS

Fibrous cap ulceration, plaque haemorrhage and excavation are sequential phenotypes of plaque disruption resulting from the chiselling effect of haemodynamic forces over unmatched mechanical tissue strength. This chain of events may result in thromboembolic events independently of the degree of stenosis.

Change of Heart: The Underexplored Role of Plaque Hemorrhage in the Evaluation of Stroke of Undetermined Etiology

In the evaluation of embolic strokes of undetermined source, great emphasis is often placed on cardiovascular disease, namely on atrial fibrillation. Other pathophysiologic mechanisms, however, may also be involved. Carotid artery intraplaque hemorrhage (IPH)—the presence of blood components within an atheromatous plaque—has become increasingly recognized as a possible etiologic mechanism in some cryptogenic strokes. IPH is a marker of plaque instability and is associated with ipsilateral neurologic ischemic events, even in nonstenotic carotid plaques. As recognition of carotid IPH as an etiology of embolic strokes has grown, so too has the complexity with which such patients are evaluated and treated, particularly because overlaps exist in the risk factors for atrial fibrillation and IPH. In this article, we review what is currently known about carotid IPH and how this clinical entity should be approached in the context of the evaluation of embolic strokes of undetermined source.