Evaluation of Cryptogenic Stroke With Advanced Diagnostic Techniques

Non-ECG-gated cardiac CT angiography in acute stroke is feasible and detects sources of embolism

BACKGROUND

A significant portion of cryptogenic stroke is hypothesized to be secondary to cardiac embolism. However, transthoracic echocardiogram is usually delayed after stroke, and more detailed cardiac imaging is not routinely done.

AIMS

This study aimed to determine whether non-ECG-gated cardiac CT angiography (cCTA) during hyperacute stroke would provide diagnostic quality images and act as an adjunct modality of cardiac imaging to detect sources of emboli.

METHODS

In this single-center prospective cohort study, modified Code Stroke imaging was implemented with a 64-slice CT scanner, where the longitudinal axis of CT angiography was extended from the carina to the diaphragm. The primary outcomes of image quality, recruitment feasibility, impact on hyperacute time metrics, and additional radiation dose were assessed. Secondary outcomes consisted of detection of high-risk cardiac sources of embolism, mediastinal or lung pathology, and impact on etiologic classification.

RESULTS

One hundred and twenty eligible patients were enrolled, of which 105 (87.5%) had good/moderate quality images for motion artifact and 119 (99.2%) for contrast opacification. Total CT time, door-to-needle time, and door-to-groin puncture time were unchanged with the addition of cCTA. Eighty-nine patients received a final diagnosis of ischemic stroke, of which 12/89 (13.5%) had high-risk cardioembolic findings on cCTA. Incidental findings, such as pulmonary embolism (PE) (7/89, 7.9%) and malignancy (6/89, 6.7%), were observed. cCTA led to changes in management for 19/120 (15.8%) of all patients, and reclassification of stroke etiology for 8/89 (9%) of patients.

CONCLUSIONS

Non-ECG-gated cCTA can be feasibly incorporated into Code Stroke and provide diagnostic quality images without delays in hyperacute time metrics. It can detect high-risk cardiac sources, and other findings impacting patient care. This may help reclassify a subset of cryptogenic stroke cases and improve secondary prevention.

Atrial Fibrillation and Ischemic Stroke despite Oral Anticoagulation

Patients with atrial fibrillation (AF) experiencing ischemic stroke despite oral anticoagulation (OAC), i.e., breakthrough strokes, are not uncommon, and represent an important clinical subgroup in view of the consistently high risk of stroke recurrence and mortality. The understanding of the heterogenous potential mechanism underlying OAC failure is essential in order to implement specific therapeutic measures aimed at reducing the risk of recurrent ischemic stroke. However, due to the incomplete comprehension of this phenomenon and the limited available data, secondary stroke prevention in such high-risk patients represents a clinical dilemma. There are several available strategies to prevent ischemic stroke recurrence in AF patients with breakthrough stroke in the absence of competing causes unrelated to AF, and these include continuation or change in the type of OAC, addition of antiplatelet therapy, left atrial appendage closure, or any combination of the above options. However, due to the limited available data, the latest guidelines do not provide any specific recommendations about which of the above strategies may be preferred. This review describes the incidence, the clinical impact and the potential mechanisms underlying OAC failure in AF patients. Furthermore, the evidence supporting each of the above therapeutic options for secondary stroke prevention and the potential future directions will be discussed.

Underlying causes of cryptogenic stroke and TIA in the nordic atrial fibrillation and stroke (NOR-FIB) study - the importance of comprehensive clinical evaluation

BACKGROUND

Cryptogenic stroke is a heterogeneous condition, with a wide spectrum of possible underlying causes for which the optimal secondary prevention may differ substantially. Attempting a correct etiological diagnosis to reduce the stroke recurrence should be the fundamental goal of modern stroke management.

METHODS

Prospective observational international multicenter study of cryptogenic stroke and cryptogenic transient ischemic attack (TIA) patients clinically monitored for 12 months to assign the underlying etiology. For atrial fibrillation (AF) detection continuous cardiac rhythm monitoring with insertable cardiac monitor (Reveal LINQ, Medtronic) was performed. The 12-month follow-up data for 250 of 259 initially included NOR-FIB patients were available for analysis.

RESULTS

After 12 months follow-up probable stroke causes were revealed in 43% patients, while 57% still remained cryptogenic. AF and atrial flutter was most prevalent (29%). In 14% patients other possible causes were revealed (small vessel disease, large-artery atherosclerosis, hypercoagulable states, other cardioembolism). Patients remaining cryptogenic were younger (p < 0.001), had lower CHA2DS2-VASc score (p < 0.001) on admission, and lower NIHSS score (p = 0.031) and mRS (p = 0.016) at discharge. Smoking was more prevalent in patients that were still cryptogenic (p = 0.014), while dyslipidaemia was less prevalent (p = 0.044). Stroke recurrence rate was higher in the cryptogenic group compared to the group where the etiology was revealed, 7.7% vs. 2.8%, (p = 0.091).

CONCLUSION

Cryptogenic stroke often indicates the inability to identify the cause in the acute phase and should be considered as a working diagnosis until efforts of diagnostic work up succeed in identifying a specific underlying etiology. Timeframe of 6-12-month follow-up may be considered as optimal.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02937077, EudraCT 2018-002298-23.

Cancer-related cryptogenic stroke involving the bilateral anterior and the posterior circulations: Diagnostic value of clinical and imaging characteristics

Objectives

This study analyzed the clinical and imaging characteristics of patients with cancer-related cryptogenic stroke (CCS) involving the bilateral anterior and the posterior circulations (three circulations) and evaluate the diagnostic value of clinical and imaging features for patients with cryptogenic stroke involving three circulations (CST).

Methods

Of the 12,580 patients with acute ischemic stroke, 148 patients with CST from May 2017 to November 2021 were divided into the cancer group (n = 81) and the non-cancer group (n = 67). Cardiovascular risk factors, diffusion-weighted imaging patterns of cryptogenic stroke, blood routine, coagulation routine, and biochemical routine were compared between the two groups. Multivariable logistic regression and receiver operating characteristic (ROC) curve analysis were used to determine associations between the two groups.

Results

Compared with the non-cancer group, the cancer group exhibited higher D-dimer levels (P < 0.001), fibrin degradation product (FDP, P < 0.001), international normalized ratio (INR, P = 0.014), neutrophil to lymphocyte ratio (NLR, P < 0.001), platelets to lymphocyte ratio (PLR, P = 0.001), activated partial thromboplastin time (APTT, P = 0.039), more frequent multiple lesions in three circulations (P < 0.001) and lower lymphocytes (P < 0.001), red blood cells (P < 0.001), and thrombin time (TT, P = 0.034). Furthermore, D-dimer [area under the curve (AUC) = 0.915, P < 0.001)], FDP (AUC = 0.923, P < 0.001), INR (AUC = 0.617, P = 0.014), NLR (AUC = 0.700, P < 0.001), PLR (AUC = 0.658, P = 0.001), and multiple lesions in three circulations (AUC = 0.786, P < 0.001) had potential diagnostic value in cryptogenic stroke. When combining these 6 parameters, the predictive power was improved (AUC = 0.949, P < 0.001).

Conclusion

Cryptogenic stroke involving three circulations with cancer has unique clinical features, and these potential diagnostic indicators could help patients identify CCS earlier.

Neurovascular Manifestations of Iron-Deficient Anemia: Narrative Review and Practical Reflections through a Teaching Case

Anemia is one of the most frequent diseases worldwide, affecting one-third of the general population. Anemia in general and in particular, iron-deficient anemia (IDA), has been associated to a higher risk of thrombotic manifestations, including ischemic stroke and cerebral venous thrombosis (CVT), as well as systemic extra-cerebral arterial and venous thrombosis. Despite these data, anemia is seldom considered as an etiological factor of stroke. An individual case encompassing all known neurovascular and systemic arterial and venous thrombotic manifestations related to IDA is presented with the focus on clinical reasoning issues in the diagnostic pathways, starting from the neuroradiological signs. The main questions have been identified and addressed in a narrative review of the most relevant data in the literature from a pragmatic and clinical viewpoint. The presented case concerns a 46-year-old man admitted to the Stroke Unit because of acute ischemic stroke with multiple thrombi in large intracranial and extracranial vessels, multifocal ischemic lesions in several arterial territories and the concurrent finding of asymptomatic CVT, pulmonary embolism with lung infarction and aortic thrombosis. An extended diagnostic work-up excluded the main etiologies (arterial dissection, cardiac embolism, genetic and acquired prothrombotic disorders, such as cancer and antiphospholipid syndrome), except for a severe IDA, such as to require blood transfusions followed by anticoagulant therapy for the several thrombotic manifestations. Neuroimaging and systemic vascular findings have been analyzed, and the main issues proposed by the case in the diagnostic pathway have been identified and discussed in a pragmatic clinical road map reviewing the data provided by the literature. Conclusions: IDA is a common but treatable condition that, independently or synergically, may increase the risk of thrombotic events. The diagnostic and therapeutic approach has not yet been defined, and each case should be individually addressed in a pragmatic clinical road map.

A nomogram for predicting atrial fibrillation detected after acute ischemic stroke

Background

Atrial fibrillation detected after stroke (AFDAS) is associated with an increased risk of ischemic stroke (IS) recurrence and death. Early diagnosis can help identify strategies for secondary prevention and improve prognosis. However, there are no validated predictive tools to assess the population at risk for AFDAS. Therefore, this study aimed to develop and validate a predictive model for assessing the incidence of AFDAS after acute ischemic stroke (AIS).

Methods

This study was a multicenter retrospective study. We collected clinical data from 5332 patients with AIS at two hospitals between 2014.01 and 2021.12 and divided the development and validation of clinical prediction models into a training cohort (n = 3173) and a validation cohort (n = 2159). Characteristic variables were selected from the training cohort using the least absolute shrinkage and selection operator (LASSO) algorithm and multivariable logistic regression analysis. A nomogram model was developed, and its performance was evaluated regarding calibration, discrimination, and clinical utility.

Results

We found the best subset of risk factors based on clinical characteristics and laboratory variables, including age, congestive heart failure (CHF), previous AIS/transient ischemia attack (TIA), national institutes of health stroke scale (NIHSS) score, C-reactive protein (CRP), and B-type natriuretic peptide (BNP). A predictive model was developed. The model showed good calibration and discrimination, with calibration values of Hosmer-Lemeshow χ² = 4.813, P = 0.732 and Hosmer-Lemeshow χ² = 4.248, P = 0.834 in the training and validation cohorts, respectively. The area under the ROC curve (AUC) was 0.815, 95% CI (0.777–0.853) and 0.808, 95% CI (0.770–0.847). The inclusion of neuroimaging variables significantly improved the performance of the integrated model in both the training cohort (AUC. 0.846 (0.811–0.882) vs. 0.815 (0.777–0.853), P = 0.001) and the validation cohort (AUC: 0.841 (0.804–0.877) vs. 0.808 (0.770–0.847), P = 0.001). The decision curves showed that the integrated model added more net benefit in predicting the incidence of AFDAS.

Conclusion

Predictive models based on clinical characteristics, laboratory variables, and neuroimaging variables showed good calibration and high net clinical benefit, informing clinical decision-making in diagnosing and treating patients with AFDAS.

Changes in R-wave amplitude at implantation are associated with gender and orientation of insertable cardiac monitor: observations from the confirm Rx™ body posture and physical activity study

Background

Insertable cardiac monitors (ICMs) are small subcutaneously implanted devices that detect changes in R-wave amplitudes (RWAs), effective in arrhythmia-monitoring. Although ICMs have proven to be immensely successful, electrical artefacts are frequent and can lead to misdiagnosis. Thus, there is a growing need to sustain and increase efficacy in detection rates by gaining insight into various patient-specific factors such as body postures and activities.

Methods

RWAs were measured in 15 separate postures, including supine, lying on the right-side (RS) or left-side (LS) and sitting, and two separate ICM orientations, immediately after implantation of Confirm Rx™ ICM in 99 patients.

Results

The patients (53 females and 46 males, mean ages 66.62 ± 14.7 and 66.40 ± 12.25 years, respectively) had attenuated RWAs in RS, LS and sitting by ~ 26.4%, ~ 27.8% and ~ 21.2% respectively, compared to supine. Gender-based analysis indicated RWAs in RS (0.32 mV (0.09–1.03 mV), p < 0.0001) and LS (0.37 mV (0.11–1.03 mV), p = 0.004) to be significantly attenuated compared to supine (0.52 mV (0.20–1.03 mV) for female participants. Similar attenuation was not evident for male participants. Further, parasternally oriented ICMs (n = 44), attenuated RWAs in RS (0.37 mV(0.09–1.03 mV), p = 0.05) and LS (0.34 mV (0.11–1.03 mV), p = 0.02) compared to supine (0.48 mV (0.09–1.03 mV). Similar differences were not observed in participants with ICMs in the 45°-relative-to-sternum (n = 46) orientation. When assessing the combined effect of gender and ICM orientation, female participants demonstrated plausible attenuation in RWAs for RS and LS postures compared to supine, an effect not observed in male participants.

Conclusion

This is the first known study depicting the effects on RWA due to body postures and activities immediately post-implantation with an overt impact by gender and orientation of ICM. Future work assessing the cause of gender-based differences in RWAs may be critical.

Trial registration: Clinical Trials, NCT03803969. Registered 15 January 2019 – Retrospectively registered, https://clinicaltrials.gov/NCT03803969

Prevalence of Symptomatic Nonstenotic Carotid Disease Using Simultaneous Non-Contrast Angiography and Intraplaque Hemorrhage Imaging for MR Screen Protocol

Background: To determine the prevalence of symptomatic nonstenotic carotid disease (SyNC) using simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) imaging for patients with acute stroke as an MR screen protocol and to assess imaging findings of carotid plaques. Patients and Methods: From May 2020 to October 2021, 2459 patients with suspected acute neurological symptoms were evaluated with brain diffusion-weighted imaging (DWI) and carotid SNAP imaging. We analyzed the degree of stenosis and intraplaque hemorrhage (IPH) using SNAP imaging. Prevalence of SyNC and risk factors for stroke in patients with SyNC were determined. We performed subgroup multivariate analysis between SyNC and other etiologies of stroke (non-SyNC). Results: Of 4608 carotid arteries in 2304 patients enrolled in this study, 454 (9.9%) plaques (both lesions in 128 patients) were found on SNAP imaging. Of these plaques, 353 (77.8%) showed stenosis of <50%. Of plaques with <50% stenosis, 47 (13.3%) patients had a territorial acute focal infarction. Seventeen (36.2%) were classified with embolic stroke of undetermined source (ESUS) and SyNC. High maximal wall thickness and carotid IPH were identified as influencing factors for SyNC. Conclusion: For patients with <50% stenosis and territorial infarction, SyNC is a relatively important source of stroke. Especially, high maximal wall thickness and carotid IPH are important risk factors for SyNC.

Cryptogenic stroke and TIA: Suggested diagnostic approach while waiting for evaluation and treatment guidelines

Background

Empiric strategies for secondary prevention in cryptogenic stroke and cryptogenic TIA are lacking. The best therapy to prevent recurrence depends on the cause of stroke. Attempting a correct diagnosis is therefore the fundamental goal of stroke treatment. Further investigation into the source of embolism if suspected, and determination of the etiology, even if demanding, is the needed prerequisite for optimal secondary prevention and risk reduction.

Aims

This paper discusses evaluation and treatment of cryptogenic stroke in light of recent years’ clinical trials results and developments in cardiology and neuroradiology. No ethical approval was needed for this work.

Results

Cardioembolism due to paroxysmal atrial fibrillation, patent foramen ovale, or cardiomyopathy; occult atherosclerosis from unstable plaques and hypercoagulable conditions seem to be the most common underlying causes to be revealed by further investigations. Treatment of these conditions can reduce the stroke recurrence significantly.

Conclusions

An individual approach and targeted diagnostics using advanced medical technologies in selected patients, who may benefit from a tailored treatment regimen, can help reveal a probable cause in the majority of strokes and TIAs previously classified as cryptogenic.

Validation of Risk Scores for Predicting Atrial Fibrillation Detected After Stroke Based on an Electronic Medical Record Algorithm: A Registry-Claims-Electronic Medical Record Linked Data Study

Background

Poststroke atrial fibrillation (AF) screening aids decisions regarding the optimal secondary prevention strategies in patients with acute ischemic stroke (AIS). We used an electronic medical record (EMR) algorithm to identify AF in a cohort of AIS patients, which were used to validate eight risk scores for predicting AF detected after stroke (AFDAS).

Methods

We used linked data between a hospital stroke registry and a deidentified database including EMRs and administrative claims data. EMR algorithms were constructed to identify AF using diagnostic and medication codes as well as free clinical text. Based on the optimal EMR algorithm, the incidence rate of AFDAS was estimated. The predictive performance of 8 risk scores including AS5F, C2HEST, CHADS2, CHA2DS2-VASc, CHASE-LESS, HATCH, HAVOC, and Re-CHARGE-AF scores, were compared using the C-index, net reclassification improvement, integrated discrimination improvement, calibration curve, and decision curve analysis.

Results

The algorithm that defines AF as any positive mention of AF-related keywords in electrocardiography or echocardiography reports, or presence of diagnostic codes of AF was used to identify AF. Among the 5,412 AIS patients without known AF at stroke admission, the incidence rate of AFDAS was 84.5 per 1,000 person-year. The CHASE-LESS and AS5F scores were well calibrated and showed comparable C-indices (0.741 versus 0.730, p = 0.223), which were significantly higher than the other risk scores.

Conclusion

The CHASE-LESS and AS5F scores demonstrated adequate discrimination and calibration for predicting AFDAS. Both simple risk scores may help select patients for intensive AF monitoring.

Ischaemic stroke in anticoagulated patients with atrial fibrillation

Anticoagulation substantially reduces the risk of stroke in patients with atrial fibrillation (AF). However, recent studies have shown that up to 22%-36% of patients on anticoagulation will suffer an ischaemic stroke (IS). In this narrative review, we provide an overview of risk factors, mechanisms, management of acute IS and strategies for secondary prevention for patients with AF with stroke despite oral anticoagulation. For this paper, we reviewed available literature from important studies (randomised clinical trials, meta-analyses, reviews and case series) on patients with IS despite anticoagulation. We focused on recent studies that examined safety and efficacy of acute stroke treatments and evaluation and management strategies for secondary prevention. The literature review suggests that patients with AF with IS despite anticoagulation are a heterogeneous group with several possible mechanisms, which may include reduced or non-adherence to anticoagulation, competing non-cardioembolic stroke aetiologies or cardioembolic mechanisms separate from AF. The identification of one or more possible mechanisms of stroke despite anticoagulation may allow for a more targeted and individualised approach for secondary prevention. There are limited data to guide management in such patients, and strategies to prevent recurrent strokes include strict risk factor control and therapies targeting the most likely stroke mechanism. In cases where AF is suspected to be the culprit, clinical trials are needed to test the safety and efficacy of left atrial appendage occlusion plus anticoagulation versus continued anticoagulation alone.

Promising Biomarker Candidates for Cardioembolic Stroke Etiology. A Brief Narrative Review and Current Opinion

Determining the cause of stroke is considered one of the main objectives in evaluating a stroke patient in clinical practice. However, ischemic stroke is a heterogeneous disorder and numerous underlying disorders are implicated in its pathogenesis. Although progress has been made in identifying individual stroke etiology, in many cases underlying mechanisms still remain elusive. Since secondary prevention strategies are tailored toward individual stroke mechanisms, patients whose stroke etiology is unknown may not receive optimal preventive treatment. Cardioembolic stroke is commonly defined as cerebral vessel occlusion by distant embolization arising from thrombus formation in the heart. It accounts for the main proportion of ischemic strokes, and its share to stroke etiology is likely to rise even further in future decades. However, it can be challenging to distinguish cardioembolism from other possible etiologies. As personalized medicine advances, stroke researchers' focus is increasingly drawn to etiology-associated biomarkers. They can provide deeper insight regarding specific stroke mechanisms and can help to unravel previously undetected pathologies. Furthermore, etiology-associated biomarkers could play an important role in guiding future stroke prevention strategies. To achieve this, broad validation of promising candidate biomarkers as well as their implementation in well-designed randomized clinical trials is necessary. This review focuses on the most-promising candidates for diagnosis of cardioembolic stroke. It discusses existing evidence for possible clinical applications of these biomarkers, addresses current challenges, and outlines future perspectives.

Cost-effectiveness of an insertable cardiac monitor to detect atrial fibrillation in patients with cryptogenic stroke

Background: We assessed cost-effectiveness of insertable cardiac monitors (ICMs) in a US cryptogenic stroke population. Materials & methods: We modelled lifetime costs and quality-adjusted life years for three monitoring strategies post cryptogenic stroke: ICM starting immediately, ICM starting after Holter monitoring (delayed ICM) and standard of care involving intermittent ECG and Holter monitoring. Patient characteristics and detection efficacy were based on the CRYSTAL-AF trial. AF detection altered the modelled anticoagulation therapy and subsequent stroke and bleed risks. Results & conclusion: Immediate ICM was found to be cost-effective versus standard of care and cost-saving versus delayed ICM. Results were robust to sensitivity analyses. ICMs are a cost-effective diagnostic tool for the prevention of recurrent stroke in a US cryptogenic stroke population.

Continuous electrocardiography for detecting atrial fibrillation beyond 1 year after stroke in primary care

BACKGROUND AND PURPOSE

The diagnostic benefit of using continuous ECG (cECG) for poststroke atrial fibrillation (AF) screening in a primary care setting is unclear. We aimed to assess the diagnostic yield from screening patients who previously had a stroke with a 7-day Holter monitor.

METHODS

Patients older than 49 years, naive to AF, with an ischaemic stroke over 1 year before enrolment were included. In a primary care setting, all patients were screened for AF using pulse palpation, 12-lead ECG and 7-day Holter monitoring. Further, NT-proBNP was determined at baseline.

RESULTS

7-day Holter monitoring uncovered AF in 17 of 366 patients (4.6% (95% CI 2.7 to 7.3)). The number needed to screen was 22 patients (14-37). 12-lead ECG uncovered AF in 3 patients (0.82% (95% CI 0.17 to 2.4)), and 122 patients had irregular pulse during pulse palpation (33.5% (95% CI 28.7 to 38.2)). When using 7-day Holter monitoring as reference standard, the sensitivity of pulse palpation and 12-lead ECG was 47% (95% CI 23% to 72%) and 18% (95% CI 4% to 43%). High levels (≥400 pg/mL) of NT-proBNP versus low levels (≤200 pg/mL) were not associated with AF in the univariate analysis nor when adjusted for age (OR 2.4 (95% CI 0.5 to 8.4) and 1.6 (95% CI 0.3 to 6.0)).

CONCLUSIONS

A relevant proportion of patients with stroke more than 1 year before inclusion were diagnosed with AF through 7-day Holter monitoring. Given the low sensitivities of pulse palpation and 12-lead ECG, additional cECG may be considered during poststroke primary care follow-up.

Time trends and patient selection in the use of continuous electrocardiography for detecting atrial fibrillation after stroke: a nationwide cohort study

BACKGROUND AND PURPOSE

Clinical use of continuous electrocardiography (cECG) for detecting atrial fibrillation (AF) after stroke is unclear. In a Danish nationwide cohort, we described post-stroke time trends in outpatient cECG usage and AF incidence and characterized factors associated with cECG use.

METHODS

Patients without AF discharged after their first ischaemic stroke between 2010 and 2016 were identified from Danish nationwide registries. cECG included Holter or event recording within 120 days from discharge. Cumulative incidence analysis and multivariable adjusted logistic regression were used to assess time trends and factors associated with cECG usage and AF.

RESULTS

The study population comprised 39 641 patients. Cumulative use of cECG increased threefold from 3.3% [95% confidence intervals (CI), 2.8-3.8] in 2010 to 10.5% (95% CI, 9.7-11.3) in 2016. Correspondingly, cumulative incidence of post-stroke AF increased from 1.9% (95% CI, 1.5-2.3) to 2.8% (95% CI, 2.4-3.2). Of all cECG-evaluated patients, 6.3% received an AF diagnosis versus 2.2% of the unevaluated. Receiving cECG was associated with increased odds of AF (odds ratio, 3.4; 95% CI, 2.8-4.0). Lower age, milder strokes and less comorbidity were associated with increased odds of receiving cECG. In contrast, risk factors for AF were increasing age and more comorbidity.

CONCLUSIONS

Post-stroke outpatient cECG use and AF incidence have increased over time, but screening rates were low. cECG use was associated with tripled odds of detecting AF. There was a disparity between factors associated with cECG use and risk factors of AF. This raise questions as to the appropriateness of the current clinical approach to post-stoke AF detection.

Prevalence of Ipsilateral Nonstenotic Carotid Plaques on Computed Tomography Angiography in Embolic Stroke of Undetermined Source

Background and Purpose- Embolic stroke of undetermined source (ESUS) constitutes a large proportion of acute ischemic stroke. It is crucial to identify possible stroke etiologies in this patient subgroup to individually tailor secondary stroke prevention strategies. This study aimed to assess the prevalence of carotid plaques causing <50% stenosis in ESUS patients on computed tomography angiography and the association of these plaques with ipsilateral strokes. Methods- Patients from INTERRSeCT-a multicenter prospective study of patients with acute ischemic stroke-were included in this study if their stroke etiology was not large artery atherosclerosis (>50% stenosis), and neck computed tomography angiography was obtained. Degree of stenosis (<30% versus 30%-50%), maximum plaque thickness, degree of plaque calcification (<50% versus ≥50%), plaque irregularity, ulceration, hypodensity, carotid web, and focal vessel outpouching were assessed for both carotid arteries on computed tomography angiography. Prevalence of carotid plaques with <50% stenosis (nonstenotic plaques), ipsilateral and contralateral to the stroke, in ESUS patients was determined and compared with non-ESUS patients. Features of these plaques with versus without ipsilateral stroke in ESUS patients were compared. Uni- and multivariable logistic regression was performed to determine associations between nonstenotic carotid plaque, plaque characteristics, and ipsilateral stroke in ESUS patients. Results- Four hundred forty-six patients were included in the study (median age, 73 years; 218 men), 138 of which were ESUS patients (median age, 70 years; 61 men). Nonstenotic carotid plaques (with <50% stenosis) were present in 54 of 138 (39.1%) ESUS patients. Twelve (8.7%) patients had bilateral carotid plaques. Forty (60.6%) of these plaques were ipsilateral and 26 (39.4%) contralateral to the side of the stroke (P=0.004). Nonstenotic carotid plaques were significantly associated with ipsilateral strokes (adjusted odds ratio, 1.83 [95% CI, 1.05-3.18]). Conclusions- In patients with ESUS, nonstenotic carotid plaques were significantly more common on the side of the ischemic stroke, suggesting that these plaques could be a potential stroke etiology in patients in whom the ischemic stroke is classified currently as ESUS.

Diagnostic value of N-terminal pro B-type natriuretic peptide for nonvalvular atrial fibrillation in acute ischemic stroke patients: A retrospective multicenter case-control study

BACKGROUND

The detection of Nonvalvular atrial fibrillation (NVAF) in AIS patients may be elusive and require further investigation such as electrocardiography (ECG) and Holter monitoring. The objective of this study is to evaluate the N-terminal pro B-type natriuretic peptide (NT-proBNP) diagnostic value for NVAF and the clinical outcome of AIS patients.

METHODS

We conducted a retrospective study of AIS patients in ten hospitals of the Shaanxi province. All NVAF patients and matched patients without NVAF admitted within 7 days after stroke onset were included in our study. The admission NT-proBNP receiver operating characteristic curve was drawn to determine the discriminative power of NT-proBNP in NVAF identification. Multivariate logistic regression analysis was used to examine the odds ratios (OR) of NT-proBNP for NVAF and identify the potential factors associated with the clinical outcomes in AIS patients.

RESULTS

A total of 275 NVAF cases and 275-matched controls were included in the current study. NT-proBNP was independently associated with NVAF (OR = 64.047, 95% confidence interval [CI]: 30.298-135.390, p < .001) in AIS patients. The optimal cutoff point for the NT-proBNP level to distinguish the NVAF group from the non-NVAF group was 431.0 pg/ml, with an area under curve [AUC] of 0.910 (95% CI: 0.885-0.935, p < .001). The high NT-proBNP level (OR: 3.284, 95% CI: 1.830-5.896, p < .001) was an independent indicator that was positively related to hospitalization mortality.

CONCLUSION

The rise of the serum NT-proBNP level at first admission added great contributions to the NVAF diagnosis after AIS, and was independently associated with the hospitalization mortality of AIS patients.

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.

Cryptogenic stroke

The paper considers the epidemiology and general etiological characteristics of cryptogenic stroke (CS). It discusses the concept of embolic stroke with an unknown source of embolism. It also characterizes the most significant causes of CS, such as paroxysmal atrial fibrillation, atrial cardiopathy, aortic atheroma, non-stenotic cerebral atherosclerotic plaques, and malignant neoplasms. The paper describes approaches to the diagnosis and secondary prevention of CS and proposes etiological and neuroimaging diagnostic algorithms for CI. Clinical cases are also presented.

Advanced interatrial block: A predictor of covert atrial fibrillation in embolic stroke of undetermined source

AIMS

One third of ischemic strokes are of unknown etiology. Interatrial block (IAB) is a marker of atrial electromechanical dysfunction that may predispose to the development of atrial fibrillation (AF). We hypothesized that IAB, especially in its advanced form, could be a marker of covert AF in patients with embolic stroke of undetermined source (ESUS).

METHODS

We reviewed a single center cohort of ESUS patients with no prior history of AF. According to P-wave analysis of baseline ECG we distinguished 3 groups: normal P-wave duration (P-wave < 120 ms), partial IAB (P-IAB, P-wave ≥ 120 ms) and A-IAB (A-IAB, P-wave ≥ 120 ms with biphasic morphology in inferior leads). Follow-up was done 1, 6 and 12 months after discharge; then every 6 months. AF episodes, frequent premature atrial contractions (PACs) (>1%) and atrial tachyarrhythmias (runs of >3 consecutive PACs) were detected on 24 h Holter. The primary endpoint was new-onset AF detection on follow-up by any means.

RESULTS

A high prevalence of both P-IAB (n = 30, 40%) and A-IAB (n = 23, 31%) was found in 75 ESUS patients. After a 521 day mean follow-up, 14 patients (19%) were diagnosed of AF. A-IAB independently predicted AF diagnosis (p =0.042) on follow-up. 24 h Holter analysis showed greater frequency of PACs and atrial tachyarrhythmia episodes in patients with IAB (p = 0.0275).

CONCLUSIONS

In this hypothesis-generating study, A-IAB in the setting of ESUS is an independent risk predictor of covert AF. Although additional randomized clinical trials are warranted, A-IAB identifies ESUS patients with advanced atrial disease that could potentially benefit from early oral anticoagulation in secondary prevention.

Stroke in malignancy: complexities of diagnosis and management: a case report

BACKGROUND

Although there is an established association between cancer and stroke, the role of malignancy as a causative agent or comorbidity is not always clear. Moreover, there are no established guidelines on the acute treatment of cancer-associated stroke or optimal anticoagulation. This case report illustrates the significance of these practice gaps.

CASE PRESENTATION

A 62-year-old Caucasian woman presented to our institute with acute neurological deficits and was found to have an occluded left middle cerebral artery on a computed tomographic angiogram. She was administered intravenous alteplase and underwent unsuccessful endovascular clot retrieval. Besides smoking and her age, she had no cerebrovascular risk factors, and the results of baseline investigations for the cause of stroke were negative. Subsequent computed tomography of the chest, abdomen, and pelvis showed metastatic malignancy, and in the context of a significantly elevated serum cancer antigen 19-9, we suspected a pancreatic primary cancer. A transthoracic echocardiogram demonstrated mitral regurgitation but no visible vegetation. The patient died of her illness. We made a diagnosis of cancer-associated stroke, specifically a likely case of nonbacterial thrombotic endocarditis.

CONCLUSIONS

This case highlights the importance of having a high threshold of suspicion for malignancy as a cause of stroke.

Culprit intracranial plaque without substantial stenosis in acute ischemic stroke on vessel wall MRI: A systematic review

BACKGROUND AND AIMS

Intracranial atherosclerotic plaque is associated with ischemic strokes without substantial stenosis, and needs better characterization. We aim to investigate the clinical significance of intracranial plaque without substantial stenosis by high resolution vessel wall MRI (vwMRI) through a systematic review of existing studies.

METHODS

Studies investigating intracranial arterial atherosclerotic plaques without substantial stenosis in acute ischemic stroke patients using vwMRI were systematically identified by searching the PubMed and Medline database and article reference lists. Study characteristics were recorded, the methodological quality of eligible studies was assessed, relevant clinical data were extracted, and collective data was analyzed.

RESULTS

Twenty-one studies were identified as eligible. 463 patients were included without stenosis of the intracranial arteries, and 651 patients were included with stenosis <50%. The prevalence of intracranial plaque revealed by vwMRI among acute/subacute ischemic stroke patients with non-stenotic Magnetic Resonance Angiography (MRA) was 50.6% (95% confidence interval (CI), 46.1%-55.1%). The prevalence of <50% MRA stenotic culprit plaque among acute/subacute ischemic stroke patients with a clinical diagnosis of intracranial atherosclerosis was 51.2% (95% CI, 38.4%-64.0%). Plaques features, including wall enhancement, positive remodeling, intraplaque hemorrhage, plaque location and eccentricity, were associated with acute stroke, progressive motor deficits and unfavorable overall functional outcomes.

CONCLUSIONS

Intracranial high-risk plaque with zero or mild degree of stenosis is more prevalent than previously acknowledged, and is associated with ischemic stroke and unfavorable outcome. VwMRI can identify the high-risk plaque features, which may act as a promising tool to better risk stratify these patients.

Embolic strokes of undetermined source: theoretical construct or useful clinical tool?

In 2014, the definition of embolic strokes of undetermined source (ESUS) emerged as a new clinical construct to characterize cryptogenic stroke (CS) patients with complete vascular workup to determine nonlacunar, nonatherosclerotic strokes of presumable embolic origin. NAVIGATE ESUS, the first phase III randomized-controlled, clinical trial (RCT) comparing rivaroxaban (15 mg daily) with aspirin (100 mg daily), was prematurely terminated for lack of efficacy after enrollment of 7213 patients. Except for the lack of efficacy in the primary outcome, rivaroxaban was associated with increased risk of major bleeding and hemorrhagic stroke compared with aspirin. RE-SPECT ESUS was the second phase III RCT that compared the efficacy and safety of dabigatran (110 or 150 mg, twice daily) to aspirin (100 mg daily). The results of this trial have been recently presented and showed similar efficacy and safety outcomes between dabigatran and aspirin. Indirect analyses of these trials suggest similar efficacy on the risk of ischemic stroke (IS) prevention, but higher intracranial hemorrhage risk in ESUS patients receiving rivaroxaban compared to those receiving dabigatran (indirect HR = 6.63, 95% CI: 1.38-31.76). ESUS constitute a heterogeneous group of patients with embolic cerebral infarction. Occult AF represents the underlying mechanism of cerebral ischemia in the minority of ESUS patients. Other embolic mechanisms (paradoxical embolism via patent foramen ovale, aortic plaque, nonstenosing unstable carotid plaque, etc.) may represent alternative mechanisms of cerebral embolism in ESUS, and may mandate different management than oral anticoagulation. The potential clinical utility of ESUS may be challenged since the concept failed to identify patients who would benefit from anticoagulation therapy. Compared with the former diagnosis of CS, ESUS patients required thorough investigations; more comprehensive diagnostic work-up than is requested in current ESUS diagnostic criteria may assist clinicians in uncovering the source of brain embolism in CS patients and individualize treatment approaches.

Effectiveness of the Chest Strap Electrocardiogram to Detect Atrial Fibrillation

Atrial fibrillation (AF) is a significant cause of cardioembolic strokes. AF is often symptomless and intermittent, making its detection challenging. The aim of this study was to assess the possibility to use a chest strap (Suunto Movesense) to detect AF both by cardiologists and automated algorithms. A single channel electrocardiogram (ECG) from a chest strap of 220 patients (107 AF and 111 sinus rhythm SR with 2 inconclusive rhythms) were analyzed by 2 cardiologists (Doc1 and Doc2) and 2 different algorithms (COSEn and AFEvidence). A 3-lead Holter served as the gold standard ECG for rhythm analysis. Both cardiologists evaluated the quality of the chest strap ECG to be superior to the quality of the Holter ECG; p <0.05/p <0.001 (Doc1/Doc 2). Accurate automated algorithm-based AF detection was achieved with sensitivity of 95.3%/96.3% and specificity of 95.5/98.2% with 2 AF detection algorithms from chest strap and 93.5%/97.2% and 98.2%/95.5% from Holter, respectively. P waves were detectable in 93.7% (Doc1) and 94.6% (Doc2) of the cases from the chest strap ECG with sinus rhythm and 98.2% (Doc1) and 95.5% (Doc2) from the Holter (p = n.s). In conclusion, the ECGs from both methods enabled AF detection by a cardiologist and by automated algorithms. Both methods studied enabled P-wave detection in sinus rhythm.

Prevalence of Fabry Disease and Outcomes in Young Canadian Patients With Cryptogenic Ischemic Cerebrovascular Events

Background and Purpose—

Previous studies reported Fabry disease in 0% to 4% of young patients with cryptogenic ischemic stroke (IS). We sought to determine the prevalence of Fabry and outcomes among young Canadians with cryptogenic IS or transient ischemic attack (TIA).

Methods—

We prospectively enrolled individuals aged 18 to 55 with IS or speech or motor TIA, and no cause identified despite predetermined investigation. α-galactosidase-A gene was sequenced for Fabry diagnosis. National Institutes of Health Stroke Scale score was measured at presentation to quantify stroke severity. Modified Rankin Scale determined functional outcomes ≤7 days after presentation and 6 months later.

Results—

We enrolled 365 patients with IS and 32 with TIA. α-galactosidase-A sequencing identified a single carrier of a genetic variant of unknown significance (p.R118C) and no well-recognized pathogenic variants. Mean National Institutes of Health Stroke Scale score was 3.1. Proportion of patients with modified Rankin Scale of 0 to 2 was 70.7% at ≤7 days and 87.4% at 6 months. National Institutes of Health Stroke Scale score at presentation and diabetes mellitus predicted 6-month modified Rankin Scale. Thirteen patients experienced 5 recurrent IS and 9 TIA during follow-up. No patient died. Most patients (98.7%) returned home. Among previous workers, 43% had residual working limitations.

Conclusions—

In this Canadian cohort of patients with cryptogenic IS or TIA, the prevalence of Fabry was 0.3% if p.R118C variant is considered as pathogenic. This suggests that more cost-effective methods should be applied for diagnosis of Fabry rather than systematic genetic screening in this population. Overall, cryptogenic IS in young adults is associated with favorable outcomes.

Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Triggers, Causes, and Outcome (SECRETO): Rationale and design

BACKGROUND

Worldwide, about 1.3 million annual ischaemic strokes (IS) occur in adults aged <50 years. Of these early-onset strokes, up to 50% can be regarded as cryptogenic or associated with conditions with poorly documented causality like patent foramen ovale and coagulopathies.

KEY HYPOTHESES/AIMS

(1) Investigate transient triggers and clinical/sub-clinical chronic risk factors associated with cryptogenic IS in the young; (2) use cardiac imaging methods exceeding state-of-the-art to reveal novel sources for embolism; (3) search for covert thrombosis and haemostasis abnormalities; (4) discover new disease pathways using next-generation sequencing and RNA gene expression studies; (5) determine patient prognosis by use of phenotypic and genetic data; and (6) adapt systems medicine approach to investigate complex risk-factor interactions.

DESIGN

Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) is a prospective multi-centre case-control study enrolling patients aged 18-49 years hospitalised due to first-ever imaging-proven IS of undetermined etiology. Patients are examined according to a standardised protocol and followed up for 10 years. Patients are 1:1 age- and sex-matched to stroke-free controls. Key study elements include centralised reading of echocardiography, electrocardiography, and neurovascular imaging, as well as blood samples for genetic, gene-expression, thrombosis and haemostasis and biomarker analysis. We aim to have 600 patient-control pairs enrolled by the end of 2018.

SUMMARY

SECRETO is aiming to establish novel mechanisms and prognosis of cryptogenic IS in the young and will provide new directions for therapy development for these patients. First results are anticipated in 2019.

Can neuroimaging differentiate PFO and AF-related cardioembolic stroke from the other embolic sources? Clinical-radiological correlation on a retrospective study

PURPOSE

The aim of this retrospective study was to map the specific ischemic lesion patterns of distribution in patent foramen ovale-related stroke (PFO-stroke) and atrial fibrillation-related stroke (AF-stroke) in patients with idiopatic ischemic stroke.

MATERIALS AND METHODS

750 ischaemic strokes were screened on basis of diagnostic imaging and tests: patients with known causes were excluded. 171 patients with unknown cause were selected and divided in two groups: AF-stroke (43 patients) and PFO-stroke (128 patients). Vascular territories of ischemic involvement were divided into four classes in each group: the anterior cerebral artery, the middle cerebral artery, the vertebro-cerebral artery (including the posterior cerebral artery) and multisite (MS) involvement.

RESULTS

Infarcts in vertebro-basilar territory and multisite represented each one about 32% of infarcts in PFO-stroke group and their involvement are more frequent than AF-stroke group (p = 0.03). Ischemic lesions in PFO-group were predominantly cortical (34.3%), and in AF-group cortical-subcortical (60.4%). Multisite pattern of ischemic lesion was more frequent in patients with severe degree of right to left shunts (37.5%).

CONCLUSION

In clinical practice, PFO may be considered a cause of cortical stroke on the basis of radiological findings, when VB vascular territory or MS brain involvement is present in younger patients (<50 age).

Diagnostic and Interventional Optical Angioscopy in Ex Vivo Carotid Arteries

BACKGROUND: Angioscopy – or endovascular endoscopy – is a catheter-based technique employing a flexible fiberoptic angioscope to directly visualize arterial lumen. Poor resolution and excessive stiffness of pre-existent angioscopes limited their use clinically. Recent advances resulted in novel fused optical fiber bundle angioscopes with improved flexibility and imaging resolution. Use of these devices in endovascular neurosurgery is still largely unexplored.

OBJECTIVE: To evaluate image quality and feasibility of optical angioscopes for diagnostic and interventional neuro-angioscopy in carotid arteries of human cadavers.

METHODS: A 5-F optical angioscope was used in human cadaveric carotid arteries to inspect integrity of arterial walls, identify atherosclerotic plaques and associated lesions prone to thrombogenicity, place intravascular occlusion coils, and deploy endovascular stents with real-time visualization.

RESULTS: Angioscopy provided key information about endoluminal anatomy such as presence and characteristics of atherosclerotic plaques and thrombogenic lesions not detected by conventional diagnostic methods. Direct real-time visualization of vascular lumen during endovascular interventions provided information on spatial distribution of coils, coil loop herniation, and apposition of stent cells against carotid artery wall complementary to angiography.

CONCLUSIONS: Fused optical fiber bundle angioscopes provide good-quality endoluminal images in human carotid arteries. Their use can feasibly assist in navigation of extracranial carotid arteries to inspect integrity of the arterial wall and identify atherosclerotic plaques and associated lesions vulnerable to thrombogenicity, allow placement of intravascular occlusion coils, and assess apposition of stents to vessel wall. Further in Vivo validation needs to be conducted along with additional research to improve image quality, flexibility, and size of angioscopes.

Decompressive craniectomy for malignant middle cerebral artery infarction in a 16-year old boy: a case report

Background

Cryptogenic stroke frequently occurs in younger patients and has a high risk of recurrence. Consequently, secondary prevention is often suboptimal as there is no known risk factor to target. This case demonstrates an unexpected finding of middle cerebral artery infarction and extensive malignant transformation in a 16-year-old boy more than a day post-admission. The lack of a proven culprit lesion makes this case even more intriguing and subsequently raises questions of cryptogenic mechanisms in the context of unrelated trauma.

Case presentation

A 16-year-old white boy had been stabbed in his chest but had a Glasgow Coma Scale score of 15. Over a day later he developed sudden signs and symptoms consistent with a neurological event of unknown etiology. Computed tomography demonstrated significant cerebral edema but was equivocal in its list of differentials. A computed tomography scan of his chest demonstrated no cardiac wall or vascular injury and he was transferred to our neurosurgical unit for intracranial pressure monitoring. A computed tomography angiogram revealed an unexpected finding of malignant middle cerebral artery infarction. Failure to medically manage his intracranial pressure resulted in a decompressive craniectomy less than 12-hours postictus. Despite extensive diagnostic investigations no culprit lesion was identified and no patent foramen ovale found. Since discharge he has returned to full functional status. He was the youngest patient (mean age of 43 years) out of a 10-year institutional retrospective on decompressive craniectomies for malignant middle cerebral artery infarction (n = 40) and had the singularly best Glasgow Outcome Scale score of 5.

Conclusions

This case highlights the preponderance of cryptogenic stroke in younger patients and its etiological elusiveness. It further demonstrates that age is predictive in terms of survival and functional outcome in the context of malignant middle cerebral artery infarction.

Association of Left Atrial Enlargement with Cortical Infarction in Subjects with Patent Foramen Ovale

Background and Purpose

Left atrial dysfunction has been reported in patients with patent foramen ovale (PFO). Here we investigated the role of left atrial dysfunction in the development of embolic stroke in patients with PFO.

Methods

We identified consecutive patients with embolic stroke of undetermined sources except for PFO (PFO+ESUS). Healthy subjects with PFO served as controls (PFO+control). A stratified analysis by 10-year age group and an age- and sex- matching analysis were performed to compare echocardiographic markers between groups. In the PFO+ESUS group, infarct patterns of PFO-related stroke were determined (cortical vs. cortico-subcortical) and analyzed in correlation with left atrial function parameters.

Results

A total of 118 patients and 231 controls were included. The left atrial volume indices (LAVIs) of the PFO+ESUS patients were higher than those of the PFO+controls in age groups of 40–49, 50–59, and 60–69 years (P<0.001, P=0.003, and P=0.027, respectively), and in the age- and sex-matched analysis (P=0.001). In the PFO+ESUS patients, a higher (>28 mL/m²) LAVI was more associated with the cortical infarct pattern (P=0.043 for an acute infarction and P=0.024 for a chronic infarction, both adjusted for age and shunt amount). The degree of right-to-left shunting was not associated with infarct patterns, but with the posterior location of acute infarcts (P=0.028).

Conclusions

Left atrial enlargement was associated with embolic stroke in subjects with PFO. Left atrial physiology might contribute to the development of PFO-related stroke and need to be taken into consideration for optimal prevention of PFO-related stroke.

Cryptogenic postpartum stroke

An estimated 25-40% of ischemic strokes are classified as cryptogenic, which means the cause of the cerebral infarction remains unidentified. One of the potential pathomechanisms - especially among young patients with no cardiovascular risk factors - is paradoxical embolism through a patent foramen ovale. Pregnancy, cesarean delivery and the postpartum period are associated with an increased risk of cerebrovascular events. Factors that may contribute to ischemic strokes during gestation and puerperium include classic cardiovascular risk factors, changes in hemostaseology/hemodynamics, and pregnancy-specific disorders such as pre-eclampsia, eclampsia, postpartum cerebral angiopathy or peripartum cardiomyopathy. In this case report, we present a 36-year-old thrombolysis candidate undergoing mechanical thrombectomy 3 weeks after a cesarean section due to HELLP-syndrome. After evaluation of anamnestic and diagnostic parameters, closure of the patent foramen ovale has been performed. In the absence of specific guidelines, diagnostic work-up for cryptogenic stroke should be oriented after the suspected pathomechanism based on patient history and clinical picture. As long as definite evidences emerge, management of cryptogenic stroke patients with pathogenic right-to-left shunt remains individual based on the mutual decision of the patient and the multidisciplinary medical team.

Multiple Infarcts Are Associated With Long-Term Stroke Recurrence and All-Cause Mortality in Cryptogenic Stroke Patients

Background and Purpose—

Brain infarct patterns that are observed via diffusion-weighted imaging are useful for classifying stroke subtypes. However, it is unclear whether infarct patterns can predict long-term outcomes in cryptogenic stroke patients. Herein, we investigated the association between acute brain infarct patterns and long-term stroke outcomes in cryptogenic stroke patients.

Methods—

Acute cryptogenic stroke patients were consecutively enrolled between April 2008 and March 2012. Diffusion-weighted imaging ischemic lesion patterns were classified as single lesions, scattered lesions in one vascular territory, or multiple lesions in multiple vascular territories. Survivors (at discharge) were followed up for 3 years after stroke onset.

Results—

A total of 272 cryptogenic stroke patients (132 women; aged 72±13 years) were enrolled. Among these patients, 169 (62.1%) had a single lesion, 38 (14.0%) had scattered lesions, and 65 (23.9%) had multiple lesions. Next, 261 patients (96.0%) were evaluated to assess right-to-left shunting, and 61 patients (23.4%) exhibited right-to-left shunting. On patient admission, right-to-left shunting and increased D-dimer levels were independently associated with multiple lesions but not single or scattered lesions. During the follow-up period (median, 1093 days), 30 patients (11.0%) developed recurrent stroke and 35 patients (12.9%) died. Multivariate Cox proportional hazard analyses showed that multiple infarcts were independently associated with recurrent stroke and all-cause mortality (hazard ratio, 3.79; 95% confidence interval, 2.24–6.37; P <0.001).

Conclusions—

Multiple brain infarcts on diffusion-weighted imaging were independently associated with long-term stroke outcomes in cryptogenic stroke patients.

Cancer Cell-Derived Extracellular Vesicles Are Associated with Coagulopathy Causing Ischemic Stroke via Tissue Factor-Independent Way: The OASIS-CANCER Study

Background

Cancer and stroke, which are known to be associated with one another, are the most common causes of death in the elderly. However, the pathomechanisms that lead to stroke in cancer patients are not well known. Circulating extracellular vesicles (EVs) play a role in cancer-associated thrombosis and tumor progression. Therefore, we hypothesized that cancer cell-derived EVs cause cancer-related coagulopathy resulting in ischemic stroke.

Methods

Serum levels of D-dimer and EVs expressing markers for cancer cells (epithelial cell adhesion molecule [CD326]), tissue factor (TF [CD142]), endothelial cells (CD31+CD42b-), and platelets (CD62P) were measured using flow cytometry in (a) 155 patients with ischemic stroke and active cancer (116 − cancer-related, 39 − conventional stroke mechanisms), (b) 25 patients with ischemic stroke without cancer, (c) 32 cancer patients without stroke, and (d) 101 healthy subjects.

Results

The levels of cancer cell-derived EVs correlated with the levels of D-dimer and TF+ EVs. The levels of cancer cell-derived EVs (CD326+ and CD326+CD142+) were higher in cancer-related stroke than in other groups (P<0.05 in all the cases). Path analysis showed that cancer cell-derived EVs are related to stroke via coagulopathy as measured by D-dimer levels. Poor correlation was observed between TF+ EV and D-dimer, and path analysis demonstrated that cancer cell-derived EVs may cause cancer-related coagulopathy independent of the levels of TF+ EVs.

Conclusions

Our findings suggest that cancer cell-derived EVs mediate coagulopathy resulting in ischemic stroke via TF-independent mechanisms.

Age disparity in diagnostic evaluation of stroke patients: Embolic Stroke of Undetermined Source Global Registry Project

Introduction: Incomplete evaluation of stroke patients may result in an unclear diagnosis. Our objective was to determine if older stroke patients more often undergo incomplete diagnostic evaluations versus younger patients in an international cohort. Patients and methods: The Embolic Stroke of Undetermined Source Global Registry was a retrospective cohort of consecutive stroke patients evaluated at 19 stroke centers in 19 countries. Diagnostic evaluation was considered as complete if the patient had, at a minimum, brain computed tomography or magnetic resonance imaging with evidence of infarction, extracranial and intracranial vascular imaging, electrocardiography, ≥24 h of cardiac rhythm monitoring, and echocardiography. Patients were diagnosed with Embolic Stroke of Undetermined Source if brain imaging confirmed a nonlacunar infarction and no stroke etiology was determined after complete evaluation. Completeness of evaluation was compared between patients ≥75 versus <75 years old. Results: The registry included 2132 patients with recent ischemic stroke during 2013-2014, of which 349 were diagnosed with Embolic Stroke of Undetermined Source. Embolic Stroke of Undetermined Source patients ≥75 years were less likely to undergo brain magnetic resonance imaging (74% versus 89%, p = 0.001), transesophageal echocardiography (22% versus 39%, p = 0.005), and combination transthoracic and transesophageal echocardiography (16% versus 32%, p = 0.005) compared with Embolic Stroke of Undetermined Source patients <75 years. Discussion: Our study has identified an international age disparity in fundamental diagnostic testing for older patients with stroke of unknown etiology. Some testing biases were affected by geographic location (e.g., brain MRI was less frequently used in European ESUS patients), whereas other testing was implemented less frequently in the elderly regardless of location (e.g., transesophageal echocardiogram). Conclusion: Older patients in this international cohort had less sophisticated diagnostic testing for stroke, despite advanced age being well established as an independent risk factor for recurrent stroke. This was a global problem and further investigations are warranted to explore the cause.