DNA Content in Ischemic Stroke Thrombi Can Help Identify Cardioembolic Strokes Among Strokes of Undetermined Cause

Association Between Thrombus Composition and Etiology in Patients With Acute Ischemic Stroke Treated by Thrombectomy

BACKGROUND

In ischemic stroke due to large vessel occlusion, cerebral blood flow is impaired by thromboemboli, which can originate from various sources in the body. A better understanding of thromboembolus composition can improve our understanding of the underlying pathophysiology and potentially guide improvement of prevention strategies. The aim of this study therefore was to perform a large-sample multi-parameter quantitative histological analysis of retrieved thromboemboli from stroke patients.

METHODS

Thromboemboli (n=501) were collected from thrombectomy-treated ischemic stroke patients at AZ Groeninge Hospital (Kortrijk, Belgium) and CHU Lille (Lille, France). Stroke etiology was determined by the treating stroke specialist using the TOAST classification system (Trial of ORG 10172 in Acute Stroke Treatment). Extensive histological analysis, blinded to stroke etiology, was performed for key thrombus constituents including red blood cells (RBCs), platelets, fibrin, von Willebrand Factor, leukocytes, citrullinated histone H3 (as a marker for neutrophil extracellular traps), and extracellular (ex)DNA. Quantitative histology results were linked to etiology.

RESULTS

Compared with large-artery atherosclerotic thromboemboli, cardioembolic thromboemboli contained significantly fewer RBCs and significantly more platelets, fibrin, leukocytes, and exDNA. Interestingly, cryptogenic thromboemboli contained relatively low amounts of RBCs and high amounts of platelets, similar to cardioembolic thromboemboli. A multivariable logistic regression model indicated that it is difficult to predict stroke etiology based on the individual thrombus composition.

CONCLUSIONS

Based on a large sample cohort of stroke thromboemboli, we found that cardiac thromboemboli contained fewer RBCs and more platelets than atherosclerotic thromboemboli and that cryptogenic thromboemboli have a similar composition to cardiac thromboemboli in terms of RBCs and platelets.

Thrombus composition in ischaemic stroke: histological and radiological evaluation, and implications for acute clinical management

Ischaemic stroke is one of the key causes of morbidity and mortality worldwide. Although rapid reperfusion through thrombolysis or mechanical thrombectomy is the cornerstone of acute management, the efficacy of these interventions is influenced by the underlying composition of the occluding thrombus, which varies widely. Histological examination of retrieved thrombi allows the determination of thrombus composition and may inform aetiology and secondary prevention strategies. Additionally, radiological features may provide valuable pre-treatment insights into thrombus composition to help predict treatment success. This narrative review discusses histological and radiological indicators of thrombus composition, and how this may predict success of thrombolysis and thrombectomy. Furthermore, it discusses how these insights can be applied in the diagnostic work-up of embolic stroke of undetermined source (ESUS), and the potential utility of emerging biomarkers relating to thrombus formation, in order to optimise secondary prevention strategies.

Proteomic Composition of Acute Ischemic Stroke Thrombi Retrieved via Endovascular Thrombectomy Is Associated with Stroke Etiology

The objective of this study is to investigate the protein components of acute ischemic stroke (AIS) thrombi using four-dimensional independent data acquisition (4D-DIA) proteomics and reveal the correlations between thrombotic protein components and AIS etiology. From April to September 2023, we enrolled a total of 30 patients who underwent endovascular thrombectomy at our institute and were diagnosed in accordance with large artery atherosclerosis (LAA; n = 15) or cardioembolism (CE; n = 15). Thromboembolic material was collected for 4D-DIA proteomic detection. We then analyzed it for differentially expressed proteins (DEPs; fold change [FC] ≥ 1.5 or ≤ 0.67), performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, and mapped protein-protein interactions (PPIs). In the 30 retrieved clots, 5115 proteins were expressed. Of these, we screened 246 DEPs between the LAA and CE groups, such as histone H4, collagen α1, and differentially expressed in neoplastic versus normal cells domain-containing protein 6A. GO analysis revealed that the DEPs' most important biological process was cellular process, the most important Cell Component was cell part, the molecular function was binding, and the most significantly enriched pathway was thiamine metabolism. PPI results revealed complicated interactions among these DEPs, of which superoxide dismutase, catalase, and γ-enolase might play important roles. This study outlines a promising molecular approach to differentiating the etiology of AIS between CE and LAA through the proteomics of retrieved thrombi, which might also inform future research into thrombotic biology.

Assessment of associations between neutrophil extracellular trap biomarkers in blood and thrombi in acute ischemic stroke patients

Inflammation including immunothrombosis by neutrophil extracellular traps (NETs) has important implications in acute ischemic stroke and can affect reperfusion status, susceptibility to stroke associated infections (SAI) as well as functional clinical outcome. NETs were shown to be prevalent in stroke thrombi and NET associated markers were found in stroke patients' blood. However, little is known whether blood derived NET markers reflect the amount of NETs in thrombi. Conclusions from blood derived markers to thrombus composition might open avenues for novel strategies in diagnostic and therapeutic approaches. We prospectively recruited 166 patients with acute ischemic stroke undergoing mechanical thrombectomy between March 2018 and May 2021. Available thrombi (n = 106) were stained for NET markers DNA-histone-1 complexes and myeloperoxidase (MPO). Cell free DNA (cfDNA), deoxyribonuclease (DNase) activity, MPO-histone complexes and a cytokine-panel were measured before thrombectomy and after seven days. Clinical data, including stroke etiology, reperfusion status, SAI and functional outcome after rehabilitation, were collected of all patients. NET markers were present in all thrombi. At onset the median concentration of cfDNA in blood was 0.19 µg/ml increasing to 0.30 µg/ml at 7 days. Median DNase activity at onset was 4.33 pmol/min/ml increasing to 4.96 pmol/min/ml at 7 days. Within thrombi DNA-histone-1 complexes and MPO correlated with each other (ρ = 0.792; p < 0.001). Moreover, our study provides evidence for an association between the amount of NETs and endogenous DNase activity in blood with amounts of NETs in cerebral thrombi. However, these associations need to be confirmed in larger cohorts, to investigate the potential clinical implications for individualized therapeutic and diagnostic approaches in acute ischemic stroke.

Top of basilar syndrome due to vertebral artery dissection: How high-resolution MRI and CD31 analysis of thrombus could help

INTRODUCTION AND IMPORTANCE

Vertebral artery dissection is a rare but serious condition that can lead to neurological deficits and even death. It is commonly associated with trauma or underlying vascular diseases. Top of basilar syndrome (TOBS) is a neurological condition that can result from vertebral artery dissection, either by direct ischemia or secondary occlusion due to distal embolization of injured inner vascular tissue. We here present a patient who was initially suffering from seizure then had TOBS due to a progressive vertebral artery dissection, with emphasis of high-resolution MRI imaging and immunohistochemistry study of the thrombus.

CASE PRESENTATION

A young male presented to the emergency department with sudden onset of seizure. A history of recent neck exercise was reported. The patient had gaze palsy, adduction disability, and dysarthria. High-resolution MRI showed a vertebral artery dissection with evidence of occlusion of the top of basilar artery. After the thrombectomy, a pathologic study revealed CD31[+] tissue in the thrombus, indicating an origin from dissected vertebral artery.

CLINICAL DISCUSSION AND CONCLUSION

It's important to recognize and treat vertebral artery dissection promptly due to its varying symptoms. Using high-resolution MRI at early stage and conducting pathologic analysis of CD31 on the thrombus can assist in the diagnosis, potentially leading to more precise treatment plans and better outcomes for patients.

Thrombus composition and thrombolysis resistance in stroke

A State of the Art lecture titled "Thrombus Composition and Thrombolysis Resistance in Stroke" was presented at the ISTH Congress in 2022. Intravenous thrombolysis (IVT) remains the only pharmacologic option to re-establish cerebral perfusion at the acute phase of ischemic stroke. IVT is based on the administration of recombinant tissue plasminogen activator with the objective of dissolving fibrin, the major fibrillar protein component of thrombi. Almost 30 years on from its introduction, although the clinical benefits of IVT have been clearly demonstrated, IVT still suffers from a relatively low efficacy, with a rate of successful early recanalization below 50% overall. Analyses of thrombectomy-recovered acute ischemic stroke (AIS) thrombi have shown that apart from occlusion site, thrombus length, and collateral status, AIS thrombus structure and composition are also important modulators of IVT efficacy. In this article, after a brief presentation of IVT principle and current knowledge on IVT resistance, we review recent findings on how compaction and structural alterations of fibrin together with nonfibrin thrombus components such as neutrophil extracellular traps and von Willebrand factor interfere with IVT in AIS. We further discuss how these new insights could soon result in the development of original adjuvant therapies for improved IVT in AIS. Finally, we summarize relevant new data presented during the 2022 ISTH Congress.

TICI-RANKIN mismatch: Poor clinical outcome despite complete endovascular reperfusion in the ETIS Registry

INTRODUCTION

Endovascular treatment (EVT) is a well-established technic for acute ischemic stroke, but despite a high recanalization rate of near 80%, at 3 months roughly 50% of patients have a poor functional outcome with a modified Rankin score (mRS) ≥3. The aim of this study was to determine predictive factors of poor functional outcomes in patients with complete recanalization after EVT, defined as modified thrombolysis in cerebral infarction (mTICI) 3.

PATIENTS AND METHODS

This retrospective analysis based on the prospective multicenter ETIS registry (endovascular treatment in ischemic stroke) in France included 795 patients from January 2015 and November 2019 with acute ischemic stroke due to anterior circulation occlusion and prestroke mRS 0-1, treated with EVT and who achieved complete recanalization. Univariate and multivariate logistic regression models were used to identify predictive factors of poor functional outcome.

RESULTS

365 patients (46%) showed a poor functional outcome (mRS>2). In backward-stepwise logistic regression analysis, poor functional outcome was independently associated with older age (OR per 10-year increase, 1.51; 95%CI, 1.30 to 1.75), higher admission NIHSS (OR per 1 point increase, 1.28; 95%CI, 1.21 to 1.34), absence of prior intravenous thrombolysis (OR, 0.59; 95%CI, 0.39 to 0.90), and an unfavorable 24-hour NIHSS change (24h-baseline) (OR, 0.82; 95%CI, 0.79 to 0.87). We calculated that patients whose 24h NIHSS decreased by less than 5 points are more at risk of a poor outcome, with a sensitivity and a specificity of 65.0%.

CONCLUSION

Despite complete reperfusion after EVT, half of patients had a poor clinical outcome. These patients, who were mainly older with a high initial NIHSS and an unfavorable post-EVT 24h NIHSS change, could represent a target population for early neurorepair and neurorestorative strategies.

A Bibliometric Analysis of Cardioembolic Stroke From 2012 to 2022

Cardioembolic stroke, a subtype of ischemic stroke with the worst prognosis, is quietly threatening public health. We aimed to visualize the development trend and hotspots of research on cardioembolic stroke. A total of 2886 papers about cardioembolic stroke published from 2012 to 2022 were retrieved in the Web of Science Core Collection (WoSCC) database. Further, we performed a bibliometric analysis of these publications, such as generating cooperation maps, co-citation analysis of journals and references, and cluster analysis of keywords. According to the results, cardioembolic stroke research faces many clinical challenges. We obtained the knowledge maps of countries/institutions, authors, journals with high publications and citations, and representative references in this field. Studies about optimal prevention strategies for cardioembolic stroke, identification of cardioembolism in cryptogenic stroke, and prophylactic anticoagulation for patients with embolic stroke of undetermined source (ESUS) or at high risk of left ventricle (LV) thrombus are in the spotlight.

Advancing Stroke Research on Cerebral Thrombi with Omic Technologies

Cerebrovascular diseases represent a leading cause of disability, morbidity, and death worldwide. In the last decade, the advances in endovascular procedures have not only improved acute ischemic stroke care but also conceded a thorough analysis of patients' thrombi. Although early anatomopathological and immunohistochemical analyses have provided valuable insights into thrombus composition and its correlation with radiological features, response to reperfusion therapies, and stroke etiology, these results have been inconclusive so far. Recent studies applied single- or multi-omic approaches-such as proteomics, metabolomics, transcriptomics, or a combination of these-to investigate clot composition and stroke mechanisms, showing high predictive power. Particularly, one pilot studies showed that combined deep phenotyping of stroke thrombi may be superior to classic clinical predictors in defining stroke mechanisms. Small sample sizes, varying methodologies, and lack of adjustments for potential confounders still represent roadblocks to generalizing these findings. However, these techniques hold the potential to better investigate stroke-related thrombogenesis and select secondary prevention strategies, and to prompt the discovery of novel biomarkers and therapeutic targets. In this review, we summarize the most recent findings, overview current strengths and limitations, and present future perspectives in the field.

High thrombus platelet content is associated with a lower rate of first pass effect in stroke treated by endovascular therapy

BACKGROUND AND PURPOSE

First pass effect (FPE), the occurrence of complete reperfusion after one pass with no rescue attempt during endovascular therapy (EVT), is associated with the best clinical outcome after an acute ischemic stroke (AIS). Previous studies evaluating FPE occurrence according to EVT technical strategies, occlusion locations, or thrombus composition have provided controversial results. Here, we performed a correlation analysis between FPE occurrence and AIS thrombus cellular composition, as assessed using quantitative biochemical assays.

PATIENTS AND METHODS

Homogenates of AIS thrombi from 250 patients were prepared by mechanical grinding. Platelet, red blood cell (RBC), and leukocyte contents of AIS thrombi were respectively estimated by quantification of GP (glycoprotein) VI, heme, and DNA in thrombus homogenates. FPE was defined as a modified Thrombolysis in Cerebral Infraction (mTICI) score of 2C or 3 after a single EVT device pass.

RESULTS

AIS thrombi successfully removed after a single pass were poorer in GPVI (0.098 ± 0.023 vs 0.111 ± 0.024 ng/mg, p < 0.001) compared to those whose removal had required several passes. GPVI content was also significantly associated with a higher number of device passes and a longer procedure time. No such significant correlation was found with DNA and heme content.

DISCUSSION AND CONCLUSION

Thrombus platelet content may hamper thrombus removal by EVT. This result suggests that adjunctive therapies or functionalization of retrieval devices targeting platelets may improve EVT efficacy.

Clot Morphology in Acute Ischemic Stroke Decision Making

Stroke is a leading cause of death and disability in the world, and the provision of reperfusion therapy and endovascular therapy, in particular, have revolutionized the treatment of patients with stroke and opened opportunities to look at brain clots retrieved after the procedure. The use of histopathology and molecular profiling of clots is of growing research and clinical interest. However, its clinical implications and incorporation within stroke workflows remain suboptimal. Recent studies have indicated that the study of brain clots may inform the mechanism of stroke and hence guide treatment decision-making in select groups of patients, especially patients without a defined cause or known mechanism. This article provides a comprehensive overview of various clot histopathological examinations in acute stroke-care settings, their clinical utility, and existing gaps and opportunities for further research. We also provide targeted recommendations to improve clot analysis workflow, hence standardizing its incorporation into clinical practice.

The Impact of Standardized Health Education in Patients with Ischemic Stroke on Patient Management Satisfaction and Quality of Clinical Management Services

Aim

Ischemic stroke is a common brain disease, which seriously affects the quality of life of patients. The purpose of this study was to evaluate the impact of the application of standardized health education in ischemic stroke patients on patient management satisfaction and clinical management service quality.

Methods

220 patients with ischemic stroke were chosen for study target. The research objects were randomly divided into control group (n = 110) and education group (n = 110) by odd even number draw lots. The control group conducted conventional treatment; on the basis of the control group, the education group received standardized health education. The impact of the application of standardized health education in patients with ischemic stroke on patient management satisfaction and clinical management service quality was analyzed.

Results

The number of health error items in the two groups decreased significantly after 2 months and 3 months of treatment, contrast to before admission, and the number of health error items in the education group was lower than that in the control group, and the difference was statistically significant. After 3 months of treatment, the daily activity score increased and the neurological function score decreased in the two groups, and the daily activity score in the education group was higher than that in the control group, and the neurological function score was lower than that in the control group; the difference was statistically significant. The satisfaction scores of patients in the education group in different aspects such as staff working attitude, health management, diet management, and environmental management were higher than those in the control group, and the disparity was obvious.

Conclusion

The application of standardized health education in patients with ischemic stroke has certain clinical value.

Composition and Organization of Acute Ischemic Stroke Thrombus: A Wealth of Information for Future Thrombolytic Strategies

During the last decade, significant progress has been made in understanding thrombus composition and organization in the setting of acute ischemic stroke (AIS). In particular, thrombus organization is now described as highly heterogeneous but with 2 preserved characteristics: the presence of (1) two distinct main types of areas in the core—red blood cell (RBC)-rich and platelet-rich areas in variable proportions in each thrombus—and (2) an external shell surrounding the core composed exclusively of platelet-rich areas. In contrast to RBC-rich areas, platelet-rich areas are highly complex and are mainly responsible for the thrombolysis resistance of these thrombi for the following reasons: the presence of platelet-derived fibrinolysis inhibitors in large amounts, modifications of the fibrin network structure resistant to the tissue plasminogen activator (tPA)-induced fibrinolysis, and the presence of non-fibrin extracellular components, such as von Willebrand factor (vWF) multimers and neutrophil extracellular traps. From these studies, new therapeutic avenues are in development to increase the fibrinolytic efficacy of intravenous (IV) tPA-based therapy or to target non-fibrin thrombus components, such as platelet aggregates, vWF multimers, or the extracellular DNA network.

Unusual Histopathological Findings in Mechanically Removed Stroke Thrombi - A Multicenter Experience

Background

Several studies have investigated the histopathology of mechanically retrieved thrombi from stroke patients. Thrombi with unusual components constitute about 1–2% of all stroke thrombi in clinical practice. Knowledge about these rare components is limited.

Objectives

To characterize the histopathology of unusual stroke thrombi from a real-world setting with relation to clinical presentation, patient characteristics and procedural aspects of mechanical thrombectomy.

Methods

One-thousand and eight thrombi retrieved from stroke patients with mechanical thrombectomy at three different hospitals were retrospectively reviewed for unusual histological components. Fifteen thrombi were included in the study for further histopathological analysis. Clinical data and data on procedural aspects were collected.

Results

We identified six cases with large amounts of extracellular DNA, of which three were calcified. All six cases except one received anticoagulant therapy. We describe two types of calcifications that differ with respect to general calcification morphology, von Kossa staining pattern, macrophage immunophenotype and presence of multinucleated giant cells. Cholesterol-rich (n = 3), adipocyte-like pattern-rich (n = 2), collagen-rich (n = 2) and myxomatous (n = 1) thrombi were also identified and are discussed with regard to pathogenesis and clinical and intervention characteristics. Finally, a thrombus with parts of a vascular wall is described. Suggestions for future studies are made and clinical and technical aspects of the management for these rare but important patients are discussed.

Conclusion

In our retrospective multicenter study, we characterized stroke thrombi histopathologically and found subgroups of thrombi defined by presence of rarely seen components. These defined subgroups showed relation to underlying cardiovascular disease, patient characteristics, and mechanical thrombectomy technique. Knowledge about these components may increase our understanding of stroke pathophysiology and influence interventional procedures.

Impact of COVID-19 on thrombus composition and response to thrombolysis: Insights from a monocentric cohort population of COVID-19 patients with acute ischemic stroke

BACKGROUND

Resistance to fibrinolysis, levels of procoagulant/antifibrinolytic neutrophil extracellular traps (NETs), and the severity of acute ischemic stroke (AIS) are increased by COVID-19. Whether NETs are components of AIS thrombi from COVID-19 patients and whether COVID-19 impacts the susceptibility of these thrombi to thrombolytic treatments remain unknown, however.

OBJECTIVES

We aimed to characterize AIS thrombi from COVID-19 patients by immunohistology and to compare their response to thrombolysis to that of AIS thrombi from non-COVID-19 patients.

PATIENTS/METHODS

For this monocentric cohort study, 14 thrombi from COVID-19 AIS patients and 16 thrombi from non-COVID-19 patients, all recovered by endovascular therapy, were analyzed by immunohistology or subjected to ex vivo thrombolysis by tissue-type plasminogen (tPA)/plasminogen.

RESULTS

COVID-19 AIS thrombi were rich in neutrophils and contained NETs, but not spike protein. Thrombolysis assays revealed a mean resistance profile to tPA/plasminogen of COVID-19 AIS thrombi similar to that of non-COVID-19 AIS thrombi. The addition of DNase 1 successfully improved thrombolysis by potentiating fibrinolysis irrespective of COVID-19 status. Levels of neutrophil, NETs, and platelet markers in lysis supernatants were comparable between AIS thrombi from non-COVID-19 and COVID-19 patients.

CONCLUSIONS

These results show that COVID-19 does not impact NETs content or worsen fibrinolysis resistance of AIS thrombi, a therapeutic hurdle that could be overcome by DNase 1 even in the context of SARS-CoV-2 infection.

Thrombus Composition, Imaging, and Outcome Prediction in Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

New imaging techniques have advanced our ability to capture thrombus characteristics and burden in real time. An improved understanding of recanalization rates with thrombolysis and endovascular thrombectomy based on thrombus characteristics has spurred interest in new therapies for acute stroke.

METHODS AND RESULTS

This article reviews the biochemical, structural, and imaging characteristics of intracranial thrombi in acute ischemic stroke; the relationship between thrombus composition and response to lytic and endovascular therapies; and current and future directions for improving outcomes in patients with acute stroke based on thrombus characteristics.

DISCUSSION

Thrombus composition, size, location, and timing from stroke onset correlate with imaging findings in acute ischemic stroke and are associated with clinical outcome. Further research across multiple domains could assist in better applying our knowledge of thrombi to patient selection and individualization of acute therapies.

[Cryptogenic stroke management : where are we ?]

Cryptogenic stroke is an old definition that designates an ischemic stroke with no identifiable cause. The term of the embolic stroke of undetermined source was then introduced to identify non-lacunar strokes in whom thromboembolism was the likely mechanism. This subgroup of cryptogenic strokes remains heterogeneous with many potential and possibly associated embolic causes. Covert atrial fibrillation is probably less often involved than initially expected, in contrast to intracranial and extracranial atherosclerosis. The cardiologist should be involved in the search of underlying causes of ischemic stroke by helping the neurologist to identify the most likely diagnosis. Further research is necessary to select populations that may benefit from more effective and individualized treatment.

Studying Stroke Thrombus Composition After Thrombectomy: What Can We Learn?

The composition of ischemic stroke thrombi has gained an increasing amount of interest in recent years. The implementation of endovascular procedures in standard stroke care has granted researchers the unique opportunity to examine patient thrombus material. Increasing evidence indicates that stroke thrombi are complex and heterogenous, consisting of various biochemical (eg, fibrin, von Willebrand Factor, and neutrophil extracellular traps) and cellular (eg, red blood cells, platelets, leukocytes, and bacteria) components. This complex composition may explain therapeutic limitations and also offer novel insights in several aspects of stroke management. Better understanding of thrombus characteristics could, therefore, potentially lead to improvements in the management of patients with stroke. In this review, we provide a comprehensive overview of the lessons learned by examining stroke thrombus composition after endovascular thrombectomy and its potential relevance for thrombectomy success rates, thrombolysis, clinical outcomes, stroke etiology, and radiological imaging.

Clot Composition Analysis as a Diagnostic Tool to Gain Insight into Ischemic Stroke Etiology: A Systematic Review

Mechanical thrombectomy renders the occluding clot available for analysis. Insights into thrombus composition could help establish the stroke cause. We aimed to investigate the value of clot composition analysis as a complementary diagnostic tool in determining the etiology of large vessel occlusion (LVO) ischemic strokes (International Prospective Register of Systematic Reviews [PROSPERO] registration # CRD42020199436). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we ran searches on Medline (using the PubMed interface) and Web of Science for studies reporting analyses of thrombi retrieved from LVO stroke patients subjected to mechanical thrombectomy (January 1, 2006 to September 21, 2020). The PubMed search was updated weekly up to February 22, 2021. Reference lists of included studies and relevant reviews were hand-searched. From 1,714 identified studies, 134 eligible studies (97 cohort studies, 31 case reports, and six case series) were included in the qualitative synthesis. Physical, histopathological, biological, and microbiological analyses provided information about the gross appearance, mechanical properties, structure, and composition of the thrombi. There were non-unanimous associations of thrombus size, structure, and composition (mainly proportions of fibrin and blood formed elements) with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiology and underlying pathologies, and similarities between cryptogenic thrombi and those of known TOAST etiology. Individual thrombus analysis contributed to the diagnosis, mainly in atypical cases. Although cohort studies report an abundance of quantitative rates of main thrombus components, a definite clot signature for accurate diagnosis of stroke etiology is still lacking. Nevertheless, the qualitative examination of the embolus remains an invaluable tool for diagnosing individual cases, particularly regarding atypical stroke causes.

The role of leukocytes in acute ischemic stroke-related thrombosis: a notable but neglected topic

Ischemic stroke is one of the most serious diseases today, and only a minority of patients are provided with effective clinical treatment. Importantly, leukocytes have gradually been discovered to play vital roles in stroke thrombosis, including promoting the activation of thrombin and the adhesion and aggregation of platelets. However, they have not received enough attention in the field of acute ischemic stroke. It is possible that we could not only prevent stroke-related thrombosis by inhibiting leukocyte activation, but also target leukocyte components to dissolve thrombi in the cerebral artery. In this review, we expound the mechanisms by which leukocytes are activated and participate in the formation of stroke thrombus, then describe the histopathology of leukocytes in thrombi of stroke patients and the influence of leukocyte composition on vascular recanalization effects and patient prognosis. Finally, we discuss the relevant antithrombotic strategies targeting leukocytes.

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.