Histological features of intracranial thrombi in stroke patients with cancer

Cerebral thrombus analysis as a useful diagnostic tool for infective endocarditis in ischemic stroke patients

INTRODUCTION

Infective endocarditis (IE) is a life-threatening condition and a rare cause of ischemic stroke (IS). This study aimed to evaluate the utility of analyzing cerebral thrombi, obtained through endovascular thrombectomy in IS, for the pathological diagnosis of IE.

PATIENTS AND METHODS

Cerebral thrombi from three groups of IS patients were compared: definite IE (n = 10), cardioembolic stroke without and with concomitant infection (CE-I-: n = 30, CE-I+: n = 10). We performed histological examination, molecular biology, and microbiological tests on cerebral thrombi, to detect microorganisms and assess their composition.

RESULTS

Median age of included patients was 73 years and 50% were females. Hematoxylin & Eosin and Grocott-Gomori Methenamine Silver stains detected microorganisms in all IE cerebral thrombi, and none in the control groups. Thrombus PCR detected relevant microorganism in n = 2/7 IE. Compared to control groups, IE thrombi were characterized by significant lower content of red blood cells (median [IQR]: IE = 7.4 [4.2-26.7], CE-I- = 49.3 [17-62.6], CE-I+ = 57.5 [40.7-60.8], % over thrombus section area [%TSA], p = 0.001), increased von Willebrand Factor (IE = 23.9 [19.1-32], CE-I- = 11.2 [8.2-12.8], CE-I+ = 12.9 [10.7-18.3], %TSA, p = 0.001), cell-dominant pattern of Neutrophil Extracellular Traps (IE = 100%, CE-I- = 69%, CE-I+ = 70%, p ⩽ 0.001), and more frequent sub-acute or chronic thrombus age classification (p ⩽ 0.001). These latter thrombus features displayed good discriminative ability between IE and controls, with AUC values between 0.84 and 0.95.

DISCUSSION

Multimodal analysis of cerebral thrombi in IS with suspected IE supports early and definite pathological diagnosis by detecting pathogens and assessing changes in thrombus composition.

Histological differences among thrombi in thrombotic diseases

PURPOSE OF REVIEW

This review aims to summarize the histological differences among thrombi in acute myocardial infarction, ischemic stroke, venous thromboembolism, and amniotic fluid embolism, a newly identified thrombosis.

RECENT FINDINGS

Acute coronary thrombi have a small size, are enriched in platelets and fibrin, and show the presence of fibrin and von Willebrand factor, but not collagen, at plaque rupture sites. Symptomatic deep vein thrombi are large and exhibit various phases of time-dependent histological changes. Cancer-associated venous thromboemboli contain invasive cancer cells that penetrate the vascular walls, and small cancer cell aggregates are observed within the thrombi. The thrombus composition in atherosclerotic and cardioembolic ischemic strokes varies from case to case, while the thrombi in cancer-associated ischemic stroke are rich in platelets and fibrin. A pathological study on amniotic fluid embolism identified uterine vein thrombi and massive platelet-rich microthrombi in the lungs.

SUMMARY

Atherothrombus formation is induced by plaque disruption and may occlude a narrow lumen within a short time. Venous thrombi may grow to a large size in a multistage or chronic manner. Cancer cells can directly contribute to venous thrombus formation. The thrombus formation in amniotic fluid embolism may explain the occurrence of consumptive coagulopathy and cardiopulmonary collapse.

High fibrin and platelet clot predicts stroke recurrence or mortality after thrombectomy in patients with active cancer

BACKGROUND

Fibrin and platelet (FP)-rich clots have been shown to be associated with cancer-related stroke. This study aims to investigate the prognostic role of thrombus composition in clinical outcomes among cancer patients who experienced stroke and received endovascular thrombectomy (EVT).

METHODS

We included acute ischemic stroke patients who underwent EVT between March 2015 and November 2021. These patients were categorized into three groups: those with active cancer, those with non-active cancer, and those without cancer. The percentages of FP in clots were quantified under hematoxylin and eosin staining. The primary outcome was defined as any stroke recurrence or mortality within 90 days following the index stroke event.

RESULTS

A total of 420 patients with retrieved clots were included in the study. This cohort comprised 50 patients with active cancer, 23 patients with non-active cancer, and 347 patients without cancer. The percentage of FP was significantly higher in thrombi retrieved from patients with active cancer compared with the other two groups. Patients in the active cancer group exhibited a higher rate of the primary outcome compared with the other groups. After adjusting for clinical variables, a higher percentage of FP in thrombi remained significantly associated with the primary outcome in the active cancer group (adjusted odds ratio (aOR) =1.03 (1.00-1.06), P=0.028), but not in the other two groups.

CONCLUSION

Among stroke patients receiving EVT, thrombi with a higher percentage of FP not only identify individuals with active cancer but also predict stroke recurrence or mortality within 90 days.

The influence of baseline platelet on mortality risk in stroke and cancer patients: a cross-sectional analysis of the NHANES database

BACKGROUND

Platelet count and function may be closely related to survival and prognosis of stroke and cancer. However, little is known on the impact of platelet count on the patients with a history of stroke and cancer. This study aimed to examine the association between baseline platelet level and all-cause mortality in this population using a cross-sectional analysis.

METHODS

Participants with a history of stroke and cancer were selected from the database of the National Health and Nutrition Examination Survey from 2007 to 2018. A maximum selected rank statistic was conducted to determine platelet cutoff with the most significant association with mortality. The association between platelet and mortality was characterized visually using restricted cubic spline (RCS). Weighted multivariable Cox regression models were performed to evaluate the association between platelet count and mortality. Time-dependent receiver operating characteristic (ROC) analysis was conducted to assess the accuracy of platelet count in predicting mortality.

RESULTS

Forty-three (43/113, 38.05%) stroke patients with cancer were alive at a median follow-up of 42 months (interquartile range, 23-74 months). The RCS analysis demonstrated a linear relationship between platelet and mortality (nonlinear, p = 0.352). Mortality in higher-platelet group (> 209 × 109/L, n = 57) was decreased than lower-platelet group (≤ 209 × 109/L, n = 56) (Model 1 HR 0.43, 95% CI 0.24-0.77, p = 0.005) (Model 2 HR 0.58, 95% CI 0.35-0.96, p = 0.03). Subgroup analyses showed no significant interaction between platelet and age, sex, BMI, WBC and neutrophil. The areas under time-dependent ROC curve of the 1-, 2-, 3-, 4- and 5-year survival rates were 0.54, 0.55, 0.57, 0.53, 0.59 for mortality of stroke patients with cancer.

CONCLUSIONS

Lower platelet count may be an independent predictor of all-cause mortality in population with a history of stroke and cancer. This result may provide valuable insights for the long-term management in stroke patients with cancer.

Thrombus composition and its implication in ischemic stroke assessment and revascularization treatments

INTRODUCTION

Since mechanical thrombectomy has allowed ischaemic stroke thrombus retrieval, the exhaustive study of this material has enabled better understanding of the potential physiopathological processes involved in thrombus formation.

DEVELOPMENT

Thrombotic pathways involved in the different vascular beds share common mechanisms, causing difficulties in the identification of specific patterns associated with stroke aetiology. However, other factors such as clot formation time, associated inflammatory status, or activation of additional immune and coagulation pathways (neutrophil extracellular trap [NET] delivery, platelet aggregation, endothelial activation, and von Willebrand Factor release) have been described as determinants in thrombus characteristics. Thus, variable proportions of fibrin-/platelet-rich and erythrocyte-rich areas are closely interrelated within the thrombus, frequently associated with a protective outer shell with high concentrations of fibrin, NETs, and von Willebrand Factor. The presence of these components, as well as their distribution and interrelationships, have been shown to have effects on the thrombus' resistance to revascularisation treatments. Understanding of these pathways has enabled the development of adjuvant therapies capable of enhancing current fibrinolytic drugs and/or increasing the efficacy of endovascular treatments.

CONCLUSION

Understanding of thrombus components and mechanisms involved in thrombus formation represent a potential pathway for the development of ischaemic stroke therapeutics with promising perspectives.

Clot signature in patients with large vessel occlusion stroke and concomitant active cancer

BACKGROUND AND PURPOSE

Patients with active cancer face an increased risk of ischemic stroke. Also, stroke may be an initial indicator of cancer. In patients with large vessel occlusion (LVO) stroke treated with thrombectomy, analysis of the clot composition may contribute new insights into the pathological connections between these two conditions.

METHODS

We compared the content of 64 consecutively retrieved clots from LVO stroke patients with concomitant active cancer and 64 clots from matched-control LVO stroke patients without a history of cancer. Clots were analyzed with respect to histological composition by Martius Scarlet Blue, von Willebrand factor (vWF), citrullinated histone H3 (H3Cit, a biomarker of NETS), CD42b, and CD3 expression by immunohistochemistry. Orbit Image Analysis was used for quantification. Differences between groups were tested using the Mann-Whitney U-test and Chi-square Test.

RESULTS

Clots from patients with concomitant cancer had a significantly higher content of vWF (median 26 [IQR13-38]% vs. 10 [4-18]%, p < 0.0001) and H3Cit (median 0.11 [IQR0.02-0.46]% vs. 0.05 [0.00-0.28]% p = 0.027) than controls. The presence of collagen >1% within the retrieved clots was highly indicative of cancer, occurring in 16/64 with active cancer and in 3/64 controls, p = 0.002. After correction for multiple comparisons, the statistical significance for H3Cit was lost. Red and white blood cells, platelets, fibrin, and expression of CD3 and CD42b did not differ between the groups.

CONCLUSIONS

Clots from LVO patients with concomitant active cancer possess distinct characteristics, indicating an influence of cancer on the innate immune system, fibroblasts, and the vascular endothelium in the formation of LVO clots.

Usefulness of Mechanical Thrombectomy in Patients with Cancer Who Developed Cerebral Infarction

Mechanical thrombectomy (MT) is an established treatment for large vessel occlusion in the acute phase of stroke. However, its efficacy and safety in patients with cancer remain unclear. This study aimed to evaluate the therapeutic effect of MT against large vessel occlusion between patients with and without cancer. A total of 71 patients who underwent MT from August 2014 to November 2021 were included in this study. Patients with cancer and/or a history of cancer (n = 16) were included in the with cancer group and the remaining patients in the without cancer group (n = 55). The frequency of preoperative tissue plasminogen activator administration was significantly lower in the with cancer group (n = 2 [12.5%]) than in the without cancer group (n = 24 [43.6%]). However, there were no significant differences between the two groups in terms of treatment time, pass frequency, thrombolysis in cerebral infarction grade, modified Rankin scale score at 1 week after treatment [mRS (1w) ], modified Rankin scale score at discharge [mRS (ENT) ], modified Rankin scale score at 90 days after treatment [mRS (90 days) ], and length of hospital stay (days). In the multivariate analysis, if the objective variables were mRS (1w) and mRS (90 days), the National Institutes of Health Stroke Scale (NIHSS) and preonset mRS scores were considered significant variables. The presence or absence of cancer was not considered an independent factor of mRS (1w), mRS (ENT), or mRS (90 days). Aggressive treatment may be recommended to patients with cancer and/or a history of cancer who present with a systemic condition that can be managed with MT.

Epidemiology, Pathophysiology, and Management of Cancer-Associated Ischemic Stroke

Cancer and stroke are leading causes of global disability and mortality. With improvements in cancer-associated mortality and advancements in treatment of active malignancy, it is more common to encounter patients with ischemic stroke and active malignancy. Evidence suggests that cancer-associated ischemic stroke is a unique subtype of stroke; however, there is limited guidance when considering diagnostic workup, secondary prevention, rehabilitation, and future directions within this population. In this narrative review, we aim to describe the epidemiology, pathophysiological mechanisms, management, and future directions regarding understanding of cancer-associated ischemic stroke.

Outcomes in ischemic and hemorrhagic stroke patients with cancer: The Japan Stroke Data Bank

INTRODUCTION

Data on the impact of malignancy on outcomes in patients with stroke, especially hemorrhagic stroke, are limited. We aimed to clarify the association between cancer and outcomes for each stroke type (ischemic/hemorrhagic) using a hospital-based multicenter stroke registration database.

PATIENTS AND METHODS

Study participants were adult patients within 7 days of the onset of ischemic stroke (IS) or hemorrhagic stroke (HS) between 2000 and 2020 in the Japan Stroke Data Bank (JSDB). The patients were categorized into two groups according to whether they had a history of cancer. Outcomes included good functional outcomes, representing a modified Rankin Scale score of 0-2 at discharge and in-hospital mortality.

RESULTS

Of the 203,983 patients analyzed in this substudy, 152,591 (women, 39.9 %; median age, 75 years) had IS, and 51,392 (48.6 %; 69 years) had HS. Of these, 6409 IS (4.2 %) and 1560 HS (3.0 %) patients had any cancer. IS patients with cancer had a lower frequency of good functional outcomes (47.5 % vs. 56.3 %; adjusted odds ratio [aOR] 0.85, 95 % confidence interval [CI] 0.79-0.91) and a higher incidence of in-hospital mortality (6.7 % vs. 4.5 %; aOR 1.59, 95 % CI 1.41-1.80) than those without cancer. HS patients with cancer showed a lower frequency of good functional outcome (24.9 % vs. 35.7 %; aOR 0.88, 95 % CI 0.78-0.99) and higher incidence of in-hospital mortality (20.1 % vs. 16.0 %; aOR 1.26, 95 % CI 1.04-1.52) than those without cancer.

CONCLUSIONS

Both IS and HS patients with cancer had significantly lower good functional outcomes and more in-hospital mortality.

Impact of D-dimer on the outcomes of endovascular thrombectomy for acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

There has been growing data about the association between D-dimer levels and thrombectomy outcomes in acute ischemic stroke patients (AIS) with no cumulative evidence. This systematic review and meta-analysis aim to discuss and analyze the findings of the current studies to provide more robust evidence in this regard.

METHODS

A systematic search was conducted through PubMed, Web of Science, Embase, and Scopus to retrieve all relevant investigations. A meta-analysis was conducted, and the results were presented in odds ratio (ORs) for binary variables and ratio of means (ROM) for continuous variables, each accompanied by its respective 95% confidence intervals (CIs).

RESULTS

After searching and screening, 14 studies were included. The analysis showed that the low D-dimer group had significantly higher rates of favorable functional outcome (OR: 4.40; 95%CI: 2.65-7.30; p < 0.001, n = 3) and recanalization (OR: 4.13; 95%CI: 1.57-10.84; p = 0.004, n = 3) than the high one. The association between D-dimer levels and first-pass effect and re-occlusion risk was also demonstrated. Eventually, two studies also demonstrated a significant association between high D-dimer levels and deep venous thrombosis and symptomatic intracranial hemorrhage as post-thrombectomy complications.

CONCLUSION

Current evidence indicates a significant association between D-dimer levels and post-thrombectomy outcomes in AIS patients. However, current data are remarkably heterogeneous, and additional comparative investigations are needed.

Absence of the Susceptibility Vessel Sign with Cancer-Associated Hypercoagulability-Related Stroke

BACKGROUND AND PURPOSE

The susceptibility vessel sign, a hypointense signal on MR T2-weighted gradient-recalled echo images, is associated with erythrocyte-predominant thrombi, which are often present in cardioembolism. In contrast, cancer-associated hypercoagulability (CAH)-related stroke, which is presumably caused by fibrin-predominant thrombi, is associated with the absence of the susceptibility vessel sign. We hypothesized that the prevalence of the susceptibility vessel sign may be helpful in distinguishing CAH-related stroke from cardioembolism. This study attempted to validate this hypothesis and investigated the usefulness of the susceptibility vessel sign in differentiating CAH-related stroke from cardioembolism.

MATERIALS AND METHODS

We retrospectively studied patients with both CAH-related stroke (CAH group) and cardioembolism (cardioembolism group) who had major cerebral artery occlusion on MRA that was performed within 6 hours of stroke onset. All patients visited our department from 2015 to 2021. CAH-related stroke was defined as the following: 1) complication of active cancer, 2) pretreatment D-dimer value of >3 μg/mL, 3) multiple vascular territory infarctions, and 4) lack of any other specifically identified causes of stroke. We compared susceptibility vessel sign positivity rates within each group. Multivariable logistic regression analysis was used to assess the association between the absence of the susceptibility vessel sign and CAH-related stroke.

RESULTS

Of 691 patients with CAH-related stroke or cardioembolism, major cerebral artery occlusion was observed in 10 patients in the CAH group and 198 patients in the cardioembolism group. The absence of the susceptibility vessel sign was identified in 55 of 208 patients and was significantly more frequent in the CAH group versus the cardioembolism group (90% versus 24%, P < .05). For predicting CAH-related stroke, the absence of the susceptibility vessel sign demonstrated a sensitivity of 90% (95% CI, 59%-99%), specificity of 78% (95% CI, 71%-83%), a positive predictive value of 18% (95% CI, 10-31), a negative predictive value of 99% (95% CI, 96%-99%), and a likelihood ratio of 4.06. Multivariable logistic regression analysis revealed that the absence of the susceptibility vessel sign was independently associated with CAH-related stroke (OR, 43; 95% CI, 6.8-863; P < .01).

CONCLUSIONS

The absence of the susceptibility vessel sign was more frequent in CAH-related stroke than in cardioembolism. These findings could potentially be helpful for clinical management and differentiating cardioembolism and CAH-related stroke.

Prevalence of right-to-left shunt in stroke patients with cancer

BACKGROUND AND OBJECTIVES

Cancer is associated with an increased risk of acute ischemic stroke (AIS) and venous thromboembolism. The role of a cardiac right-to-left shunt (RLS) as a surrogate parameter for paradoxical embolism in cancer-related strokes is uncertain. We sought to investigate the relationship between the presence of an RLS and cancer in AIS patients.

METHODS

We included consecutive AIS patients hospitalized at our tertiary stroke center between January 2015 and December 2020 with available RLS status as detected on transesophageal echocardiography (TEE). Active cancers were retrospectively identified and the association with RLS was assessed with multivariable logistic regression and inverse probability of treatment weighting to minimize the ascertainment bias of having a TEE obtained.

RESULTS

Of the 2236 AIS patients included, 103 (4.6%) had active cancer, of whom 24 (23%) were diagnosed with RLS. An RLS was present in 774 out of the 2133 AIS patients without active cancer (36%). After adjustment and weighting, the absence of RLS was associated with active cancer (adjusted odds ratio (aOR) 2.29; 95% confidence interval (CI), 1.14-4.58). When analysis was restricted to patients younger than 60 years of age or those with a high-risk RLS (Risk of Paradoxical Embolism Score ⩾ 6), there was no association between RLS and cancer (aOR, 3.07; 95% CI, 0.79-11.88 and aOR, 0.56; 95% CI, 0.10-3.10, respectively).

CONCLUSION

RLS was diagnosed less frequently in AIS patients with cancer than in cancer-free patients, suggesting that arterial sources may play a larger role in cancer-related strokes than paradoxical venous embolization. Future studies are needed to validate these findings and evaluate potential therapeutic implications, such as the general indication, or lack thereof, for patent foramen ovale (PFO) closure in this patient population.

Successful Recanalization and Neurological Restoration in Cancerous Embolic Cerebral Infarction via Endovascular Stent-Retriever Embolectomy

Mechanical thrombectomy has emerged as a promising treatment for acute ischemic stroke caused by large vessel occlusion. However, cases involving cancerous emboli retrieved during endovascular embolectomy are rare. We present a case of a 65-year-old man with a history of heavily treated rectal cancer, who developed a middle cerebral artery (MCA) infarction due to metastatic adenocarcinoma. The patient presented with sudden onset right-side weakness, right facial palsy, global aphasia, and left gaze deviation, with a National Institutes of Health Stroke Scale (NIHSS) score of 16. Following intravenous thrombolysis, endovascular thrombectomy was performed, achieving nearly complete recanalization. Pathological examination of the retrieved thrombus revealed metastatic adenocarcinoma of rectal origin. The patient's neurological deficits gradually improved, and he was successfully discharged to undergo further palliative therapy. This case underscores the importance of considering mechanical thrombectomy for patients with advanced solid organ malignancy presenting with acute ischemic stroke, even when the etiology could be a tumor embolus. Our findings highlight the potential for mechanical thrombectomy to restore neurological function in such cases, allowing patients to proceed to the next level of care with a reasonably good post-stroke quality of life.

Diagnosing cancer-associated ischemic stroke: A systematic review of hematological biomarkers

BACKGROUND AND AIM

Patients suffering from cancer are reported to have an increased risk of ischemic stroke (IS). We aimed to identify cancer-associated biomarkers found to differentiate between IS associated with cancer from those not associated with cancer.

SUMMARY OF REVIEW

We performed a systematic search of PubMed and EMBASE databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The study is reported in PROSPERO (#CRD42022355129). In total, 5563 papers were screened, of which 49 papers were included. Seven biomarkers were identified which had the potential to differentiate between patients who had cancer or stroke or both conditions. D-dimer was the most frequently monitored biomarker, and high levels were significantly associated with cancer-related strokes in (42/44) studies. Fibrinogen was significantly associated with cancer-related strokes in 11/27 studies. A higher level of C-reactive protein, investigated in 19 studies, was associated with cancer-related strokes, but conclusive multivariate analysis was not performed. Finally, the four cancer-associated antigens CA125, CA153, CA199, and carcinoembryonic antigen were only reported on in three to six studies, respectively. These studies all originated from the Guangxi province in China. CA125 was associated with an increased risk of IS in four of six studies.

CONCLUSION

Increased D-dimer seems associated with cancer-related IS. CRP may also be a candidate as a cancer-associated stroke biomarker, but this requires further verification. Fibrinogen and the more specific cancer biomarkers have not yet been proven helpful for detecting cancer-related strokes.

Arterial Thrombosis in Patients with Cancer

Patients with cancer are at increased risk of arterial thromboembolic disease due to the presence of risk factors common to both the development of cancer and arterial thrombosis, the cancer itself, and the treatments provided to treat cancer. We review here the epidemiology and pathophysiology of arterial thromboembolic disease in cancer, along with its prevention and treatment strategies. We also propose a generalized approach for the management of arterial thromboembolic disease in this patient population.

Neuro-oncologic Emergencies

OBJECTIVE

Neuro-oncologic emergencies have become more frequent as cancer remains one of the leading causes of death in the United States, second only to heart disease. This article highlights key aspects of epidemiology, diagnosis, and management of acute neurologic complications in primary central nervous system malignancies and systemic cancer, following three thematic classifications: (1) complications that are anatomically or intrinsically tumor-related, (2) complications that are tumor-mediated, and (3) complications that are treatment-related.

LATEST DEVELOPMENTS

The main driver of mortality in patients with brain metastasis is systemic disease progression; however, intracranial hypertension, treatment-resistant seizures, and overall decline due to increased intracranial burden of disease are the main factors underlying neurologic-related deaths. Advances in the understanding of tumor-specific characteristics can better inform risk stratification of neurologic complications. Following standardized grading and management algorithms for neurotoxic syndromes related to newer immunologic therapies is paramount to achieving favorable outcomes.

ESSENTIAL POINTS

Neuro-oncologic emergencies span the boundaries of subspecialties in neurology and require a broad understanding of neuroimmunology, neuronal hyperexcitability, CSF flow dynamics, intracranial compliance, and neuroanatomy.

Embolic strokes of undetermined source: a clinical consensus statement of the ESC Council on Stroke, the European Association of Cardiovascular Imaging and the European Heart Rhythm Association of the ESC

One in six ischaemic stroke patients has an embolic stroke of undetermined source (ESUS), defined as a stroke with unclear aetiology despite recommended diagnostic evaluation. The overall cardiovascular risk of ESUS is high and it is important to optimize strategies to prevent recurrent stroke and other cardiovascular events. The aim of clinicians when confronted with a patient not only with ESUS but also with any other medical condition of unclear aetiology is to identify the actual cause amongst a list of potential differential diagnoses, in order to optimize secondary prevention. However, specifically in ESUS, this may be challenging as multiple potential thromboembolic sources frequently coexist. Also, it can be delusively reassuring because despite the implementation of specific treatments for the individual pathology presumed to be the actual thromboembolic source, patients can still be vulnerable to stroke and other cardiovascular events caused by other pathologies already identified during the index diagnostic evaluation but whose thromboembolic potential was underestimated. Therefore, rather than trying to presume which particular mechanism is the actual embolic source in an ESUS patient, it is important to assess the overall thromboembolic risk of the patient through synthesis of the individual risks linked to all pathologies present, regardless if presumed causally associated or not. In this paper, a multi-disciplinary panel of clinicians/researchers from various backgrounds of expertise and specialties (cardiology, internal medicine, neurology, radiology and vascular surgery) proposes a comprehensive multi-dimensional assessment of the overall thromboembolic risk in ESUS patients through the composition of individual risks associated with all prevalent pathologies.

Cancer patients and ischemic stroke

Patients with cancer have an increased risk of ischemic stroke compared to the general population. Additionally, these patients have a worse prognosis compared to stroke patients without cancer. Activation of coagulation appears to play a key role in the pathophysiology of ischemic stroke in patients with cancer. However, the underlying mechanisms remain unknown. Moreover, we do not have a way to identify cancer patients with a high risk of stroke and cannot develop prevention strategies. Therefore, there is an urgent need for neurologists and oncologists to develop screening and prevention strategies for stroke in patients with cancer. In this review, we summarize the characteristics of cancer patients at a high risk of stroke, the predictors for the development of stroke and survival in cancer patients, and possible treatments.

Cancer-Associated Stroke: Thrombosis Mechanism, Diagnosis, Outcome, and Therapeutic Strategies

Cancer can induce hypercoagulability, which may lead to stroke. This occurs when tumor cells activate platelets as part of their growth and metastasis. Tumor cells activate platelets by generating thrombin and expressing tissue factor, resulting in tumor cell-induced platelet aggregation. Histopathological studies of thrombi obtained during endovascular thrombectomy in patients with acute stroke and active cancer have shown a high proportion of platelets and thrombin. This underscores the crucial roles of platelets and thrombin in cancer-associated thrombosis. Cancer-associated stroke typically occurs in patients with active cancer and is characterized by distinctive features. These features include multiple infarctions across multiple vascular territories, markedly elevated blood D-dimer levels, and metastasis. The presence of cardiac vegetations on echocardiography is a robust indicator of cancer-associated stroke. Suspicion of cancer-associated stroke during endovascular thrombectomy arises when white thrombi are detected, particularly in patients with active cancer. Cancer-associated stroke is almost certain when histopathological examination of thrombi shows a very high platelet and a very low erythrocyte composition. Patients with cancer-associated stroke have high risks of mortality and recurrent stroke. However, limited data are available on the optimal treatment regimen for stroke prevention in these patients. Thrombosis mechanism in cancer is well understood, and distinct therapeutic targets involving thrombin and platelets have been identified. Therefore, direct thrombin inhibitors and/or antiplatelet agents may effectively prevent stroke recurrence. Additionally, this strategy has potential benefits in cancer treatment as accumulating evidence suggests that aspirin use reduces cancer progression, metastasis, and cancer-related mortality. However, clinical trials are necessary to assess the efficacy of this strategy involving the use of direct thrombin inhibitors and/or antiplatelet therapies.

Development of an algorithm for identifying paraneoplastic ischemic stroke in association with lung, pancreatic, and colorectal cancer

Background

Paraneoplastic ischemic stroke has a poor prognosis. We have recently reported an algorithm based on the number of ischemic territories, C-reactive protein (CRP), lactate dehydrogenase (LDH), and granulocytosis to predict the underlying active cancer in a case-control setting. However, co-occurrence of cancer and stroke might also be merely incidental.

Objective

To detect cancer-associated ischemic stroke in a large, unselected cohort of consecutive stroke patients by detailed analysis of ischemic stroke associated with specific cancer subtypes and comparison to patients with bacterial endocarditis.

Methods

Retrospective single-center cohort study of consecutive 1612 ischemic strokes with magnetic resonance imaging, CRP, LDH, and relative granulocytosis data was performed, including identification of active cancers, history of now inactive cancers, and the diagnosis of endocarditis. The previously developed algorithm to detect paraneoplastic cancer was applied. Tumor types associated with paraneoplastic stroke were used to optimize the diagnostic algorithm.

Results

Ischemic strokes associated with active cancer, but also endocarditis, were associated with more ischemic territories as well as higher CRP and LDH levels. Our previous algorithm identified active cancer-associated strokes with a specificity of 83% and sensitivity of 52%. Ischemic strokes associated with lung, pancreatic, and colorectal (LPC) cancers but not with breast and prostate cancers showed more frequent and prominent characteristics of paraneoplastic stroke. A multiple logistic regression model optimized to identify LPC cancers detected active cancer with a sensitivity of 77.8% and specificity of 81.4%. The positive predictive value (PPV) for all active cancers was 13.1%.

Conclusion

Standard clinical examinations can be employed to identify suspect paraneoplastic stroke with an adequate sensitivity, specificity, and PPV when it is considered that the association of ischemic stroke with breast and prostate cancers in the stroke-prone elderly population might be largely incidental.

Acute ischaemic stroke in active cancer versus non-cancer patients: stroke characteristics, mechanisms and clinical outcomes

BACKGROUND AND PURPOSE

Demographics, clinical characteristics, stroke mechanisms and long-term outcomes were compared between acute ischaemic stroke (AIS) patients with active cancer (AC) versus non-cancer patients.

METHODS

Using data from 2003 to 2021 in the Acute STroke Registry and Analysis of Lausanne, a retrospective cohort study was performed comparing patients with AC, including previously known and newly diagnosed cancers, with non-cancer patients. Patients with inactive cancer were excluded. Outcomes were the modified Rankin Scale (mRS) score at 3 months, death and cerebrovascular recurrences at 12 months before and after propensity score matching.

RESULTS

Amongst 6686 patients with AIS, 1065 (15.9%) had a history of cancer. After excluding 700 (10.4%) patients with inactive cancer, there were 365 (5.5%) patients with AC and 5621 (84%) non-cancer AIS patients. Amongst AC patients, 154 (42.2%) strokes were classified as cancer related. In multivariable analysis, patients with AC were older (adjusted odds ratio [aOR] 1.02, 95% confidence interval [CI] 1.00-1.03), had fewer vascular risk factors and were 48% less likely to receive reperfusion therapies (aOR 0.52, 95% CI 0.35-0.76). Three-month mRS scores were not different in AC patients (aOR 2.18, 95% CI 0.96-5.00). At 12 months, death (adjusted hazard ratio 1.91, 95% CI 1.50-2.43) and risk of cerebrovascular recurrence (sub-distribution hazard ratio 1.68, 95% CI 1.22-2.31) before and after propensity score matching were higher in AC patients.

CONCLUSIONS

In a large institutional registry spanning nearly two decades, AIS patients with AC had less past cerebrovascular disease but a higher 1-year risk of subsequent death and cerebrovascular recurrence compared to non-cancer patients. Antithrombotic medications at discharge may reduce this risk in AC patients.

Malignancy-associated ischemic stroke: Implications for diagnostic and therapeutic workup

BACKGROUND

Patients with malignancies have an increased risk of suffering ischemic stroke via several mechanisms such as coagulation dysfunction and other malignancy-related effects as well as iatrogenic causes. Moreover, stroke can be the first sign of an occult malignancy, termed as malignancy-associated ischemic stroke (MAS). Therefore, timely diagnostic assessment and targeted management of this complex clinical situation are critical.

FINDINGS

Patients with both stroke and malignancy have atypical ages, risk factors, and often exhibit malignancy-related symptoms and multiple lesions on neuroimaging. New biomarkers such as eicosapentaenoic acid and blood mRNA profiles may help in distinguishing MAS from other strokes. In terms of treatment, malignancy should not be considered a contraindication, given comparable rates of recanalization and complications between stroke patients with or without malignancies.

CONCLUSION

In this review, we summarize the latest developments in diagnosing and managing MAS, especially stroke with occult malignancies, and provide new recommendations from recently emerged clinical evidence for diagnostic and therapeutic workup strategies.

Von Willebrand Factor Antigen Levels Predict Poor Outcomes in Patients With Stroke and Cancer: Findings From the Multicenter, Prospective, Observational SCAN Study

BACKGROUND

Patients with acute ischemic stroke and active cancer have more severe neurological symptoms, elevated risks of stroke recurrence, and death compared with the general population. We examined whether von Willebrand factor (vWF) antigen levels at stroke onset were associated with the poor outcomes of patients with stroke and cancer.

METHODS AND RESULTS

Using data from 90 patients with acute ischemic stroke and active cancer who were registered in the SCAN (Ischemic Stroke in Patients With Cancer and Neoplasia) study, a prospective multicenter, observational study in Japan, we divided patients into 2 groups according to their median vWF antigen levels (high, n=46; or low, n=44). The high-vWF group had a significantly higher initial National Institutes of Health Stroke Scale score (median, 7 [interquartile range, 3-11.25] versus 3 [interquartile range, 1-8.5]; P<0.05) and a significantly higher incidence of cryptogenic stroke (32 [70%] versus 16 [36%]; P<0.01) and venous thromboembolism (7 [15%] versus 0 [0%]; P<0.01), as well as multiple lesions (28 [62%] versus 12 [27%]; P<0.001), than the low-vWF group. We observed no significant difference in the rate of stroke recurrence within 1 year between the groups. However, increased vWF levels were an independent predictor of death within 1 year of stroke onset, after adjusting for potential confounders (odds ratio, 6.77 [95% CI, 1.49-30.78]; P<0.05).

CONCLUSIONS

Elevated vWF antigen levels were associated with adverse outcomes in patients with cancer-associated stroke and may represent a useful biomarker to guide future therapeutic interventions.

A Single-Center Experience of Mechanical Thrombectomy for Cancer-Associated Ischemic Stroke

Objectives

Cancer-associated ischemic stroke tends to extend over multiple vascular territories and develops under poor general conditions. Owing to the rarity of such cases and poor prognoses, no comprehensive studies on mechanical thrombectomy for cancer-associated ischemic stroke have been reported in Japan. The present study investigated the radiological and clinical characteristics of mechanical thrombectomy in patients with cancer-associated ischemic stroke at our institution.

Methods

We retrospectively reviewed 108 patients who underwent mechanical thrombectomy for large cerebral artery occlusion between January 1, 2021, and October 31, 2022, at our institution. The characteristics of mechanical thrombectomy in the cancer-associated ischemic stroke group were compared with those in the control group.

Results

Of the 108 patients (112 procedures), seven patients (eight procedures) with clinically diagnosed cancer-associated ischemic stroke underwent mechanical thrombectomy. Of the eight procedures, six were performed during hospitalization. In contrast, only 10 of 104 procedures were performed in the control group. The in-hospital onset rate was higher in the cancer-associated ischemic stroke group (75.0%) compared to that in the controls (9.6%); p <0.001. The puncture-to-reperfusion time was significantly longer in the cancer-associated ischemic stroke group in comparison to that in the controls with a median interquartile range of 69 minutes (60.0-82.0 minutes) and 59.5 minutes (44.5-69.3 minutes), respectively (p <0.01). However, the rates of successful recanalization defined as thrombolysis in cerebral infarction ≥2b were not significantly different between the cancer-associated ischemic stroke group and controls with values of 62.5% and 79.8%, respectively (p = 0.250). Of the eight cases in the cancer-associated ischemic stroke group, only one (12.5%) had a good outcome on a modified Rankin Scale score of 0 to 2 at discharge, in contrast to 23 of the 104 (23.1%) cases in the controls (p = 0.523). Histopathological examination of six retrieved thrombi in the cancer-associated stroke group using hematoxylin and eosin staining revealed that only one case showed an erythrocyte-dominant thrombus while five displayed a fibrinoplatelet-dominant component. Conversely, 65 of 92 retrieved thrombi in the control group were erythrocyte dominant. Cancer was pathologically diagnosed in four of seven patients, all of which were adenocarcinomas.

Conclusion

Cancer-associated ischemic stroke tends to occur during hospitalization. Coagulation disorders associated with cancer, especially adenocarcinoma, may be related to the formation of thrombi with fibrinoplatelet-dominant components, leading to ischemic stroke. The procedural time for mechanical thrombectomy in cancer-associated ischemic stroke tends to be longer.

Coagulation Factor Expression and Composition of Arterial Thrombi in Cancer-Associated Stroke

BACKGROUND

Cancer is associated with an increased risk of stroke. Tumor cells activate platelets, induce a coagulation cascade, and generate thrombin. The composition of thrombi may reflect the mechanism of thrombosis, aiding the determination of the treatment strategy. Here, we investigated the composition and expression of coagulation factors in the thrombi of patients with cancer-associated stroke.

METHODS

Patients with stroke who underwent endovascular thrombectomy between September 2014 and June 2020 and whose cerebral thrombi were obtained were divided into those with cancer-associated stroke (cancer group) and propensity score-matched patients without cancer (control group), using 1:1 matching based on age and sex. Immunohistochemistry was performed of the thrombi, and the composition and expression of coagulation factors were compared between groups.

RESULTS

Among the 320 patients who underwent endovascular thrombectomy and who had thrombi obtained, this study included 23 patients with cancer and 23 matched controls. In both groups, the median age was 65 years, and 12 patients (52.2%) were men. Platelet composition was significantly higher in the cancer group than in the control group (median [interquartile range], 51.3% [28.0%-61.4%] versus 9.5% [4.8%-14.0%]; P<0.001). Among coagulation factors, thrombin (26.2% [16.2%-52.7%] versus 4.5% [1.3%-7.2%]; P<0.001) and tissue factors (0.60% [0.34%-2.06%] versus 0.37% [0.22%-0.60%]; P=0.024) were higher and factor X was lower (1.25% [0.39%-3.60%] versus 2.33% [1.67%-4.48%]; P=0.034) in the cancer group. There was a positive correlation between thrombin and platelets in the cancer group (r=0.666; P=0.001) but not in the control group (r=-0.167; P=0.627).

CONCLUSIONS

Cerebral thrombi in patients with cancer-associated stroke showed higher proportions of platelets, thrombin, and tissue factors, suggesting their key roles in arterial thrombosis in cancer and providing a therapeutic perspective for preventing stroke in patients with cancer-associated stroke.

Cancer-Associated Stroke and Acute Endovascular Reperfusion Therapy

Since stroke is often associated with cancer, acute stroke patients with cancer undergoing endovascular therapy (EVT) are not uncommon. Reportedly, the proportion of such cases is approximately 6%-7% of all stroke EVT cases. Ischemic stroke in patients with active cancer (cancer-associated stroke) includes not only strokes caused by cancer-related hypercoagulability but also coincident strokes due to common etiologies, strokes associated with tumor emboli, direct tumor invasion of blood vessels, and strokes associated with cancer therapy. Stroke caused by cancer-related hypercoagulability itself encompasses various entities, including paradoxical embolism, stroke due to nonbacterial thrombotic endocarditis, and in situ arterial occlusion due to disseminated intravascular coagulation or thrombotic microangiopathy. Thus, diverse mechanisms contribute to cancer-associated stroke, emphasizing the need to consider individualized treatment strategies for acute cases involving large vessel occlusion. Observational studies have shown that EVT for cancer-associated stroke results in poorer clinical outcomes, but with comparable rates of successful reperfusion and symptomatic intracranial hemorrhage when compared with stroke patients without cancer. This suggests that denying patients EVT solely on the basis of comorbid active cancer is inappropriate, and decision-making should be shared with the patients and their families, preferably through a multidisciplinary team approach. Thrombi retrieved from patients with stroke caused by cancer-related hypercoagulability have unique characteristics, being predominantly platelet rich and difficult to retrieve. Preprocedural imaging and serum biomarkers, including the hyperdense vessel sign on non-contrast CT, susceptibility vessel sign on T2* or susceptibility-weighted MRI, three-territory sign on MRI, and D-dimer levels, are valuable in evaluating the stroke subtype and thrombus features. Thrombectomy techniques, such as contact aspiration and stent retriever monotherapy, have shown varying degrees of effectiveness for stroke caused by cancer-related hypercoagulability, warranting further study. After reperfusion therapy, appropriate treatment for the prevention of stroke recurrence should be initiated, considering the specific stroke subtypes. In conclusion, cancer-associated stroke encompasses diverse subtypes, and thrombi associated with stroke caused by cancer-related hypercoagulability present various challenges for thrombectomy. Individualized treatment approaches based on underlying mechanisms are essential for improving outcomes in acute stroke patients with active cancer. Optimization of preprocedural diagnosis, EVT techniques, and secondary prevention of stroke caused by cancer-related hypercoagulability will lead to better management of these patients and enhance their quality of life.

Thromboembolic and bleeding complications during interruptions and after discontinuation of anticoagulant treatment in patients with atrial fibrillation and active cancer: A daily practice evaluation

BACKGROUND AND AIMS

Cancer provides challenges to the continuity of anticoagulant treatment in patients with atrial fibrillation (AF), e.g. through cancer-related surgery or complications. We aimed to provide data on the incidence and reasons for interrupting and discontinuing anticoagulant treatment in AF patients with cancer and to assess its contribution to the risk of thromboembolism (TE) and major bleeding (MB).

METHODS

This retrospective study identified AF patients with cancer in two hospitals between 2012 and 2017. Data on anticoagulant treatment, TE and MB were collected during two-year follow-up. Incidence rates (IR) per 100 patient-years and adjusted hazard ratios (aHR) were obtained for TE and MB occurring during on- and off-anticoagulant treatment, during interruption and after resumption, and after permanent discontinuation.

RESULTS

1213 AF patients with cancer were identified, of which 140 patients permanently discontinued anticoagulants and 426 patients experienced one or more interruptions. Anticoagulation was most often interrupted or discontinued due to cancer-related treatment (n = 441, 62 %), bleeding (n = 129, 18 %) or end of life (n = 36, 5 %). The risk of TE was highest off-anticoagulation and during interruptions, with IRs of 19 (14-25)) and 105 (64-13), and aHRs of 3.1 (1.9-5.0) and 4.6 (2.4-9.0), respectively. Major bleeding risk were not only increased during an interruption, but also in the first 30 days after resumption, with IRs of 33 (12-72) and 30 (17-48), and aHRs of 3.3 (1.1-9.8) and 2.4 (1.2-4.6), respectively.

CONCLUSIONS

Interruption of anticoagulation therapy harbors high TE and MB risk in AF patients with cancer. The high incidence rates call for better (periprocedural) anticoagulant management strategies tailored to the cancer setting.

White Embolus-induced Basilar Artery Occlusion Due to Pulmonary Vein Invasion of a Metastasis of a Malignant Melanoma

An 80-year-old woman presented with impaired consciousness after malignant melanoma resection. Magnetic resonance angiography showed basilar artery occlusion, which was subjected to mechanical thrombectomy for recanalization. A pathological analysis of the retrieved embolus revealed that it was derived from a metastasis of malignant melanoma. Contrast-enhanced chest computed tomography showed multiple pulmonary metastases, one of which was in the right upper lobe and invaded the pulmonary vein. To our knowledge, this is the first case of white embolus-induced cerebral embolism due to pulmonary vein invasion of a metastasis of a pathologically diagnosed malignant melanoma.

Preprocedural D-Dimer Level as a Predictor of First-Pass Recanalization and Functional Outcome in Endovascular Treatment of Acute Ischemic Stroke

We aimed to evaluate the association between preprocedural D-dimer levels and endovascular and clinical outcomes. We retrospectively reviewed patients with acute intracranial large-vessel occlusion who underwent mechanical thrombectomy. Plasma D-dimer levels were measured immediately before the endovascular procedure. Endovascular outcomes included successful recanalization, first-pass recanalization (first-pass effect (FPE) and modified FPE (mFPE)), thrombus fragmentation, and the number of passes of the thrombectomy device. Clinical outcomes were assessed at 3 months using the modified Rankin Scale. A total of 215 patients were included. Preprocedural D-dimer levels were lower in patients with FPE (606.0 ng/mL [interquartile range, 268.0-1062.0]) than in those without (879.0 ng/mL [437.0-2748.0]; p = 0.002). Preprocedural D-dimer level was the only factor affecting FPE (odds ratio, 0.92 [95% confidence interval, 0.85-0.98] per 500 ng/mL; p = 0.022). D-dimer levels did not differ significantly based on successful recanalization and thrombus fragmentation. The number of passes of the thrombectomy device was higher (p = 0.002 for trend) and the puncture-to-recanalization time was longer (p = 0.044 for trend) as the D-dimer levels increased. Patients with favorable outcome had significantly lower D-dimer levels (495.0 ng/mL [290.0-856.0]) than those without (1189.0 ng/mL [526.0-3208.0]; p < 0.001). Preprocedural D-dimer level was an independent factor for favorable outcome (adjusted odds ratio, 0.88 [0.81-0.97] per 500 ng/mL; p = 0.008). In conclusion, higher preprocedural D-dimer levels were significantly associated with poor endovascular and unfavorable functional outcomes.

Cancer Prediction With Machine Learning of Thrombi From Thrombectomy in Stroke: Multicenter Development and Validation

BACKGROUND

We aimed to develop and validate machine learning models to diagnose patients with ischemic stroke with cancer through the analysis of histopathologic images of thrombi obtained during endovascular thrombectomy.

METHODS

This was a retrospective study using a prospective multicenter registry which enrolled consecutive patients with acute ischemic stroke from South Korea who underwent endovascular thrombectomy. This study included patients admitted between July 1, 2017 and December 31, 2021 from 6 academic university hospitals. Whole-slide scanning was performed for immunohistochemically stained thrombi. Machine learning models were developed using transfer learning with image slices as input to classify patients into 2 groups: cancer group or other determined cause group. The models were developed and internally validated using thrombi from patients of the primary center, and external validation was conducted in 5 centers. The model was also applied to patients with hidden cancer who were diagnosed with cancer within 1 month of their index stroke.

RESULTS

The study included 70 561 images from 182 patients in both internal and external datasets (119 patients in internal and 63 in external). Machine learning models were developed for each immunohistochemical staining using antibodies against platelets, fibrin, and erythrocytes. The platelet model demonstrated consistently high accuracy in classifying patients with cancer, with area under the receiver operating characteristic curve of 0.986 (95% CI, 0.983-0.989) during training, 0.954 (95% CI, 0.937-0.972) during internal validation, and 0.949 (95% CI, 0.891-1.000) during external validation. When applied to patients with occult cancer, the model accurately predicted the presence of cancer with high probabilities ranging from 88.5% to 99.2%.

CONCLUSIONS

Machine learning models may be used for prediction of cancer as the underlying cause or detection of occult cancer, using platelet-stained immunohistochemical slide images of thrombi obtained during endovascular thrombectomy.

Mechanical Thrombectomy for Acute Ischemic Stroke in Patients with Malignancy: A Systematic Review

Background: Ischemic stroke is a common occurrence in patients with concomitant malignancy. Systemic thrombolysis is often contraindicated in these patients, and mechanical thrombectomy (MT) is the preferred method of intervention. This review aims to collect the available data on the safety and efficacy of MT in cancer patients (CPs).Methods: The PubMed/MEDLINE and SCOPUS databases were systematically searched for studies assessing safety (mortality, intracranial hemorrhage) and efficacy (reperfusion, functional outcome) indices in CPs receiving MT. Potentially relevant parameters examined in solitary studies were also extracted (e.g., stroke recurrence, brain malignancy).Results: A total of 18 retrospective studies of various methodologies and objectives were identified. Rates of in-hospital mortality, intracranial hemorrhage of any kind, reperfusion rates, and discharge condition did not seem to present any considerable differences between CPs and patients without cancer. On the contrary, 90-day mortality was higher and 90-day functional independence was lower in CPs. Three studies on cancer-related stroke (no other identifiable etiology and high D-dimer levels in the presence of active cancer) showed constant tendencies towards unfavorable conditions. Conclusions: Per the available evidence, MT appears to be a safe treatment option for CPs. It is still unclear whether the 90-day mortality and outcome rates are more heavily influenced by the malignancy and not the intervention itself, so MT can be considered in CPs with prospects of a good functional recovery, undertaking an individualized approach.

Cancer and stroke: commonly encountered by clinicians, but little evidence to guide clinical approach

The association between stroke and cancer is well-established. Because of an aging population and longer survival rates, the frequency of synchronous stroke and cancer will become even more common. Different pathophysiologic mechanisms have been proposed how cancer or cancer treatment directly or via coagulation disturbances can mediate stroke. Increased serum levels of D-dimer, fibrin degradation products, and CRP are more often seen in stroke with concomitant cancer, and the clot retrieved during thrombectomy has a more fibrin- and platelet-rich constitution compared with that of atherosclerotic etiology. Multiple infarctions are more common in patients with active cancer compared with those without a cancer diagnosis. New MRI techniques may help in detecting typical patterns seen in the presence of a concomitant cancer. In ischemic stroke patients, a newly published cancer probability score can help clinicians in their decision-making when to suspect an underlying malignancy in a stroke patient and to start cancer-screening studies. Treating stroke patients with synchronous cancer can be a delicate matter. Limited evidence suggests that administration of intravenous thrombolysis appears safe in non-axial intracranial and non-metastatic cancer patients. Endovascular thrombectomy is probably rather safe in these patients, but probably futile in most patients placed on palliative care due to their advanced disease. In this topical review, we discuss the epidemiology, pathophysiology, and prognosis of ischemic and hemorrhagic strokes as well as cerebral venous thrombosis and concomitant cancer. We further summarize the current evidence on acute management and secondary preventive therapy.

Significance of D-Dimer in Acute Ischemic Stroke Patients With Large Vessel Occlusion Accompanied by Active Cancer

Background

This study aimed to investigate clinical outcome predictors of acute stroke patients with large vessel occlusion and active cancer and validate the significance of D-dimer levels for endovascular thrombectomy decisions.

Methods

We analyzed a prospectively collected hospital-based stroke registry to determine clinical EVT outcomes of acute stroke patients within 24 h with following criteria: age ≥18 years, NIHSS ≥6, and internal carotid artery or middle cerebral artery lesion. All patients were classified into EVT and non-EVT groups. Patients were divided into two groups by initial D-dimer level. We explored variables potentially associated with successful recanalization as well as 3-month functional outcomes and mortality rates.

Results

Among 68 patients, 36 were treated with EVT, with successful recanalization in 55.6%. The low D-dimer group showed a higher rate of successful recanalization and favorable outcome than the high D-dimer group. The mortality rate was higher in the high D-dimer group. No EVT and high D-dimer level were independent predictors of mortality, whereas lesion volume and low D-dimer level were independently associated with favorable outcomes.

Conclusions

D-dimer level is a prognostic factor in acute LVO stroke patients with active cancer, and its high value for EVT decisions provisionally supports its testing in this patient population.

The Index of Esophageal Cancer Related Ischemic Stroke: A Retrospective Patient Control Study

PURPOSE

To investigate independent risk factors for esophageal cancer-related ischemic stroke (ECIS) and to use them to develop an index of ECIS to help clinicians identify patients at high risk for ECIS or to identify ECIS from other types of ischemic stroke.

METHODS

We retrospectively enrolled active esophageal cancer (EC) patients with acute ischemic stroke (ECIS group) and patients with active EC without ischemic stroke (EC group), age- and sex-matched with ECIS patients, at seven centers from January 2011 to December 2020. Clinical data and laboratory and imaging findings were collected. Univariate and multivariate analyses were performed to analyze the independent risk factors for ECIS. Optimal cutoffs for sensitivities and specificities were obtained by Youden's J statistic following a receiver operator characteristic (ROC) analysis of each risk factor and the product of the risk factors.

RESULTS

A total of 91 ECIS patients and 91 EC patients were included. Elevated levels of carcinoembryonic antigen (CEA) [odds ratio (OR) = 0.105, 95% confidence interval (CI): 1.051-1.174, P < 0.001], D-dimer (DD) (OR = 0.003, 95% CI: 1.002-1.004, P < 0.001), and neutrophil count (OR = 0.857, 95% CI: 1.628-3.407, P < 0.001) were independent risk factors for ECIS. The area under the curve (AUC) of each independent risk factor and the product of the three independent risk factors were calculated by a receiver operator characteristic (ROC) curve, and the cutoff value from the largest AUC was called the ECIS index.

CONCLUSION

It was suggested that elevated plasma DD and CEA levels and increased neutrophils in EC patients may altogether contribute to the development of ECIS. The index of ECIS may facilitate clinicians to identify patients at high risk for ECIS or to identify ECIS from other etiologic types of ischemic stroke.

Characterization of Ferric Chloride-Induced Arterial Thrombosis Model of Mice and the Role of Red Blood Cells in Thrombosis Acceleration

PURPOSE

The ferric chloride (FeCl₃)-induced thrombosis model is widely used for thrombosis research. However, it lacks standardization with uncertainty in the exact mechanism of thrombosis. This study aimed to characterize thrombus formation in a mouse model.

MATERIALS AND METHODS

We investigated thrombus formation and stability using various FeCl₃ concentrations (10%, 20%, 30%, 40%, and 50%, w/v) in carotid arteries of the Institute of Cancer Research (ICR) and C57BL/6N mice using the FeCl₃-induced thrombosis model. We also investigated thrombus histopathology using immunohistochemistry and electron microscopy.

RESULTS

Higher FeCl₃ concentrations induced dose-dependent, faster, larger, and more stable thrombus formation in both strains of mice. However, the ICR mice showed better dose-responses in thrombus formation and stability compared to the C57BL/6N mice. Thrombi were fibrin- and platelet-rich without significant changes across FeCl₃ concentrations. However, the content of red blood cells (RBCs) increased with increasing FeCl₃ concentrations (p for trend <0.001) and inversely correlated with time to occlusion (r=-0.65, p<0.001). While platelets and fibrin were evenly distributed over the thrombus, RBCs were predominantly located near the FeCl₃ treatment area. Transmission electron microscopy showed that RBCs attached to and were surrounded by aggregates of degranulated platelets, suggesting their potential role in platelet activation.

CONCLUSION

Faster and larger thrombus formation is induced in a dose-dependent manner by a wide range of FeCl₃ concentrations, but the stable thrombus formation requires higher FeCl₃ concentrations. Mouse strain affects thrombus formation and stability. RBCs and their interaction with platelets play a key role in the acceleration of FeCl₃-induced thrombosis.

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.

Effectiveness of mechanical thrombectomy in cancer-related stroke and associated factors with unfavorable outcome

Background

The effectiveness of mechanical thrombectomy (MT) in cancer-related stroke (CRS) is largely unknown. This study aims to investigate the clinical and radiological outcomes of MT in CRS patients. We also explored the factors that independently affect functional outcomes of patients with CRS after MT.

Methods

We retrospectively reviewed 341 patients who underwent MT after acute ischemic stroke onset between May 2014 and May 2020. We classified the patients into CRS (n = 34) and control (n = 307) groups and compared their clinical details. Among CRS patients, we analyzed the groups with and without good outcomes (3-months modified Rankin scale [mRS] score 0, 1, 2). Multivariate analysis was performed to investigate the independent predictors of unfavorable outcomes in patients with CRS after MT.

Results

A total of 341 acute ischemic stroke patients received MT, of whom 34 (9.9%) had CRS. Although the baseline National institute of health stroke scale (NIHSS) score and the rate of successful recanalization was not significantly different between CRS patients and control group, CRS patients showed more any cerebral hemorrhage after MT (41.2% vs. controls 23.8%, p = 0.037) and unfavorable functional outcome at 3 months (CRS patients median 3-month mRS score 4, interquartile range [IQR] 2 to 5.25 vs. controls median 3-month mRS score 3, IQR 1 to 4, [p = 0.026]). In the patients with CRS, elevated serum D-dimer level and higher baseline NIHSS score were independently associated with unfavorable functional outcome at 3 months (adjusted odds ratio [aOR]: 1.524, 95% confidence interval [CI]: 1.043–2.226; aOR: 1.264, 95% CI: 1.010–1.582, respectively).

Conclusions

MT is an appropriate therapeutic treatment for revascularization in CRS patients. However, elevated serum D-dimer levels and higher baseline NIHSS scores were independent predictors of unfavorable outcome. Further research is warranted to evaluate the significance of these predictors.

Cancer and Embolic Stroke of Undetermined Source

One-quarter to one-third of ischemic strokes have no established mechanism after standard diagnostic evaluation and are classified as embolic stroke of undetermined source (ESUS). Failure of randomized trials to demonstrate a benefit of direct oral anticoagulants over aspirin for the treatment of ESUS as a single homogeneous entity has led to renewed interest by stroke experts to divide ESUS into subgroups. Emerging data suggest that active cancer, which is present in 5% to 10% of patients with ESUS, is a distinct and important subgroup of ESUS with unique clinical characteristics, underlying pathophysiologies, and treatment and prognostic considerations. Furthermore, the prevalence of cancer-related ESUS is expected to increase as patients with cancer, even those with distant metastases, survive longer due to improvements in cancer treatments. In this topical review, we examine the epidemiological link between ESUS and cancer, the clinical features and potential mechanistic underpinnings of ESUS with cancer (with a focus on novel biomarkers and their relationship to recurrent stroke and other thromboembolic events), and the potential treatment strategies for cancer-related ESUS. We include a critical appraisal of existing data and ongoing or planned clinical trials of different antithrombotic approaches. As cancer-related ESUS is a dynamic disease with variable course, we recommend close collaboration between neurologists and oncologists to develop individualized management plans.

Biomechanics and hemodynamics of stent-retrievers

In 2015, multiple randomized clinical trials showed an unparalleled treatment benefit of stent-retriever thrombectomy as compared to standard medical therapy for the treatment of a large artery occlusion causing acute ischemic stroke. A short time later, the HERMES collaborators presented the patient-level pooled analysis of five randomized clinical trials, establishing class 1, level of evidence A for stent-retriever thrombectomy, in combination with intravenous thrombolysis when indicated to treat ischemic stroke. In the years following, evidence continues to mount for expanded use of this therapy for a broader category of patients. The enabling technology that changed the tide to support endovascular treatment of acute ischemic stroke is the stent-retriever. This review summarizes the history of intra-arterial treatment of stroke, introduces the biomechanics of embolus extraction with stent-retrievers, describes technical aspects of the intervention, provides a description of hemodynamic implications of stent-retriever embolectomy, and proposes future directions for a more comprehensive, multi-modal endovascular approach for the treatment of acute ischemic stroke.

Embolization of tumor cells is rare in patients with systemic cancer and cerebral large vessel occlusion

BACKGROUND AND PURPOSE

Stroke is a dreaded complication in patients with cancer. Besides paraneoplastic coagulopathy, chemotherapy, radiotherapy and tumor-directed invasive procedures, circulating cancer cells may contribute to thrombus formation and embolic stroke. However, the incidence of tumor cells within the blood clots of cancer patients with stroke is unknown and the role of circulating tumor cells in the formation of cerebrovascular thrombi remains unclear.

METHODS

All patients who had undergone cerebrovascular thrombectomy at the University Hospital Zurich between 2014 and 2017 were screened for history of cancer. Clinical information was retrieved from the local stroke registry and the electronic charts and thrombi underwent a thorough histopathological re-review.

RESULTS

Thirty-two of 182 patients (18%) with thrombectomy had a history of cancer. The majority of patients had advanced stage cancer. However, even after extensive histopathological re-review, only one specimen revealed tumor cells in the thrombus: a 75-year-old patient with acute occlusion of the middle cerebral artery who had been diagnosed with non-small-cell lung cancer 8.1 months prior to stroke.

CONCLUSIONS

The presence of cancer cells in clots from cerebrovascular thrombectomy, indicative of a direct involvement of circulating tumor cells in the causation of stroke, is rare.

Outcome of Stroke Patients with Cancer and Nonbacterial Thrombotic Endocarditis

Background and Purpose

Nonbacterial thrombotic endocarditis (NBTE) is a cause of stroke in cancer. However, clinical characteristics and outcomes in stroke patients with cancer-associated NBTE are not well known.

Methods

We included consecutive patients with stroke and active cancer over a 9-year period who underwent echocardiography. We retrospectively compared clinical characteristics and presence of metastasis between patients with NBTE, those with cryptogenic etiologies, and those with determined etiologies. We also investigated mortality and stroke events during the 6-month follow-up.

Results

Among the 245 patients, 20 had NBTE, 96 had cryptogenic etiologies, and 129 had determined etiologies. Metastasis was seen in all 20 patients (100%) with NBTE, 69.8% in patients with cryptogenic etiology, and 48.8% in patients with or determined etiology. During the 6-month follow-up, 127 patients (51.8%) developed stroke and/or died (death in 110 [44.9%] and stroke events in 55 [22.4%]). Patients with NBTE showed significantly higher mortality (80%) and stroke occurrence (50%) than those with cryptogenic etiologies (mortality 54.2%, stroke 25.0%, log-rank P=0.006) and determined etiologies (mortality 32.6%, stroke 16.3%, log-rank P<0.001). In a multivariate Cox proportional hazard analysis, the presence of NBTE was independently associated with composite outcomes of mortality and stroke events (hazard ratio, 1.941; 95% confidence interval, 1.052 to 3.690).

Conclusions

NBTE should be suspected as a potential cause of stroke in patients with metastatic cancer. Patients with NBTE have a high risk of recurrent stroke and mortality. Future studies are necessary to determine strategies to reduce stroke recurrence in patients with NBTE.

Independent risk factors and the potential predictors of bladder cancer-related ischemic stroke

Objective

To investigate the independent risk factors and potential predictors of bladder cancer-related ischemic stroke (BCRIS).

Methods

This was a multi-center retrospective study including patients with active bladder cancer and acute ischemic stroke without traditional stroke risk factors (BCRIS group), and sex- and age-matched patients with active bladder cancer alone (control group). Data were collected between January 2006 and December 2018. Uni- and multivariate analyses were performed to identify independent risk factors for BCRIS. The predictive performance of these risk factors was assessed using receiver operating characteristic (ROC) curves.

Results

Records were retrospectively reviewed from 60 BCRIS patients and 120 bladder cancer controls. Univariate analysis revealed that serum D-dimer and carcinoembryonic antigen (CEA) levels and the platelet and neutrophil counts were significantly higher in BCRIS patients compared with controls. Multivariate analysis identified the three above-mentioned variables as independent risk factors for BCRIS. The product of all three factors gave the largest area under the ROC curve.

Conclusions

Elevated serum D-dimer and CEA levels and increased platelet count were independent risk factors for BCRIS, and the cut-off value based on the product of the three independent risk factors (≥2,640,745.29) could serve as a potential predictor of BCRIS.

Pathophysiologic and Therapeutic Perspectives Based on Thrombus Histology in Stroke

Recent advances in endovascular thrombectomy have enabled the histopathologic analysis of fresh thrombi in patients with acute stroke. Histologic analysis has shown that the thrombus composition is very heterogeneous between patients. However, the distribution pattern of each thrombus component often differs between patients with cardiac thrombi and those with arterial thrombi, and the efficacy of endovascular thrombectomy is different according to the thrombus composition. Furthermore, the thrombus age is related to the efficacy of reperfusion therapy. Recent studies have shown that neutrophils and neutrophil extracellular traps contribute to thrombus formation and resistance to reperfusion therapy. Histologic features of thrombi in patients with stroke may provide some clues to stroke etiology, which is helpful for determining the strategy of stroke prevention. Research on thrombus may also be helpful for improving reperfusion therapy, including the development of new thrombolytic agents.

Cancer-Related Stroke: An Emerging Subtype of Ischemic Stroke with Unique Pathomechanisms

Systemic cancer and ischemic stroke are common conditions and two of the most frequent causes of death among the elderly. The association between cancer and stroke has been reported worldwide. Stroke causes severe disability for cancer patients, while cancer increases the risk of stroke. Moreover, cancer-related stroke is expected to increase due to advances in cancer treatment and an aging population worldwide. Because cancer and stroke share risk factors (such as smoking and obesity) and treatment of cancer can increase the risk of stroke (e.g., accelerated atherosclerosis after radiation therapy), cancer may accelerate conventional stroke mechanisms (i.e., atherosclerosis, small vessel disease, and cardiac thrombus). In addition, active cancer and chemotherapy may enhance thrombin generation causing stroke related to coagulopathy. Patients with stroke due to cancer-related coagulopathy showed the characteristics findings of etiologic work ups, D-dimer levels, and infarct patterns. In this review, we summarized the frequency of cancer-related stroke among patients with ischemic stroke, mechanisms of stroke with in cancer patients, and evaluation and treatment of cancer-related stroke. We discussed the possibility of cancer-related stroke as a stroke subtype, and presented the most recent discoveries in the pathomechanisms and treatment of stroke due to cancer-related coagulopathy.