Embolic strokes of undetermined source: the case for a new clinical construct

Embolic Stroke of Undetermined Source: New Data and New Controversies on Cardiac Monitoring and Anticoagulation

Embolic strokes of undetermined source (ESUS) represent 9%-25% of all ischemic strokes. Based on the suspicion that a large proportion of cardioembolic sources remain undetected among embolic stroke of undetermined source patients, it has been hypothesized that a universal approach of anticoagulation would be better than aspirin for preventing recurrent strokes. However, 4 randomized controlled trials (RCTs), with different degrees of patient selection, failed to confirm this hypothesis. In parallel, several RCTs consistently demonstrated that prolonged cardiac monitoring increased atrial fibrillation detection and anticoagulation initiation compared with usual care in patients with ESUS, and later in individuals with ischemic stroke of known cause (e.g., large or small vessel disease). However, none of these trials or subsequent meta-analyses of all available RCTs have shown a reduction in stroke recurrence associated with the use of prolonged cardiac monitoring. In this article, we review the clinical and research implications of recent RCTs of antithrombotic therapy in patients with ESUS and in high-risk populations with and without stroke, with device-detected asymptomatic atrial fibrillation.

Prolonged and repeated microemboli detection in acute ischemic stroke - The Norwegian Microemboli in Acute Stroke Study (NOR-MASS)

OBJECTIVES

Cerebral microemboli can be detected by transcranial Doppler monitoring (TCDM) and may elucidate stroke etiology, the effect of preventive therapy, and the risk of stroke recurrence. Microemboli detection is usually performed for up to 60 minutes, but due to temporal variability, microembolization may be missed if the monitoring time is too short. We aimed to assess the time course of microembolization in acute ischemic stroke and explore the utility of prolonged and repeated microemboli detection.

MATERIALS AND METHODS

Patients with suspected ischemic stroke and symptom onset within 24 hours were examined with bilateral, stationary TCDM for one hour followed by unilateral, ambulatory TCDM for two hours. Unilateral TCDM was repeated for the following two days and after three months.

RESULTS

We included 47 patients, of which 41 had ischemic stroke, five had transient ischemic attack, and one had amaurosis fugax. Microemboli were detected in 60 % of patients. The occurrence was highest within 24 hours after onset and significantly lower at three months. Prolonged and repeated microemboli detection yielded only one additional microemboli-positive patient. Hence, patients who initially were microemboli negative tended to remain negative. We could not demonstrate an association between microemboli occurrence and clinical outcome or stroke recurrence.

CONCLUSIONS

Microembolic signals are frequent within 24 hours after ischemic stroke onset, but prolonged and repeated microemboli detection did not increase the yield of MES positive patients.

CLINICAL TRIAL REGISTRATION-URL

http://www.

CLINICALTRIALS

gov. Unique identifier: NCT03543319.

Cardiovascular Risk Factors and Disparities in Management of Embolic Stroke: A Western Sydney Perspective

BACKGROUND

Ischaemic stroke remains one of the leading causes of death and disability worldwide. The population of Western Sydney has a unique demographic with lower socioeconomic status and a culturally and linguistically diverse population. This study aims to investigate the demographics and cardiovascular risk factors of patients in Western Sydney, focusing on the prevalence and profile of cardioembolic (CE) strokes and embolic strokes of undetermined source (ESUS).

METHOD

Prospective data were collected in 463 patients with ischaemic stroke presenting to a tertiary centre in Western Sydney, who underwent predischarge transthoracic echocardiography. Patients with haemorrhagic strokes or unclear stroke diagnosis were excluded. Analysis of stroke subtype (CE, ESUS, or non-embolic) and clinical characteristics was performed based on age, gender, and prior atrial fibrillation (AF) prevalence.

RESULTS

Of the 463 patients, 147 (32%) had CE strokes, and 147 (32%) had ESUS. Cardioembolic (CE) strokes were associated with older age (≥65 years) and a history of congestive cardiac failure. Older patients had higher rates of hypertension, ischaemic heart disease, AF, and congestive heart failure. History of AF was present in 67 patients (14.5%); however, only 51% received anticoagulation before admission despite a low bleeding risk. The transthoracic echocardiography characteristics of ESUS/non-embolic strokes differed from those of CE strokes; 20% of patients with ESUS had an enlarged left atrium, suggesting a subset of patients with ESUS with a left atrial myopathy.

CONCLUSIONS

Patients with ischaemic stroke in Western Sydney have a high prevalence of cardiovascular risk factors which were often undertreated. Half of the patients with prior AF did not receive anticoagulation despite low bleeding risk, indicating a gap in optimal stroke prevention. There were distinct echocardiographic characteristics among stroke subtypes. Further analysis of left atrium parameters may provide greater insights into the pathogenesis and prevention of embolic strokes.

Early vs late anticoagulation in acute ischemic stroke with indications outside atrial fibrillation

BACKGROUND

Current literature lacks guidance on the safety of administering anticoagulation in acute ischemic stroke with emergent indications that require anticoagulation other than atrial fibrillation. Therefore, we tend to rely on studies investigating acute ischemic stroke in atrial fibrillation for anticoagulation recommendations.

METHODS

We retrospectively reviewed data for patients with acute ischemic stroke who had a non-atrial fibrillation emergent indication for anticoagulation (e.g., intra-arterial thrombus, intracardiac thrombus, acute coronary syndrome, acute limb ischemia, deep vein thrombosis and pulmonary embolism) diagnosed within 3 days of acute ischemic stroke. Patients who received anticoagulation ≤ 3 days of stroke onset (Group A) were compared to those who either received it afterwards or did not receive it at all (Group B).

RESULTS

Out of the 558 patients, only 88 patients met our inclusion criteria. Of the total cohort, 55.7 % patients were males, and basic demographics were similar in both groups except for milder strokes in Group A (national institute of health stroke scale 6 vs. 12.5, p = 0.03). Only 2 patients in Group A and 1 patient in Group B developed intracranial hemorrhage, which was not statistically significant. Group A patients had a lower incidence of both new diagnosis (2 % vs. 34.2 % %, p < 0.001) and propagation of an established venous thromboembolism. They also had a lower rate of any thromboembolic complication (2 % vs. 42 %, p < 0.001).

CONCLUSION

Early anticoagulation (i.e., ≤ 3 days) in non-atrial fibrillation ischemic stroke patients with an emergent indication may be safe and carry a lower risk of thromboembolic complications than later anticoagulation.

Dual Antiplatelet Therapy After Embolic Stroke of Undetermined Source: A Subgroup Analysis of the CHANCE-2 Trial

BACKGROUND

The atherosclerotic sources of embolism are a significant contributor to embolic stroke of undetermined source (ESUS). However, there is limited evidence for the efficacy of intensive dual antiplatelet therapy for ESUS. We conducted an investigation to determine whether gene-directed dual antiplatelet therapy could reduce the risk of recurrent stroke in patients with ESUS.

METHODS

CHANCE-2 (Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events-II) was an investigator-initiated, multicenter, randomized, double-blind, placebo-controlled trial that objectively compared ticagrelor plus aspirin and clopidogrel plus aspirin in patients with minor stroke or transient ischemic attack who carried CYP2C19 loss-of-function alleles in China. All study participants were classified into ESUS and non-ESUS groups for the prespecified exploratory analysis. Cox proportional hazards models were used to assess the interaction of the state of ESUS with the effects of dual antiplatelet therapy with ticagrelor-aspirin versus clopidogrel-aspirin, adjusting for sociodemographic and clinical factors.

RESULTS

The subgroup analysis comprised 5796 participants (90.4% of the total 6412 participants) in the CHANCE-2 trial, with a median age of 64.9 years (range, 57.0-71.4 years), of whom 1964 (33.9%) were female. These participants underwent diffusion-weighted imaging as part of the study protocol. After systematic evaluation, 15.2% of patients (881/5796) were deemed to have ESUS. The incidence of stroke recurrence in patients with ESUS was found to be 5.6% in the ticagrelor-aspirin group and 9.2% in the clopidogrel-aspirin group (hazard ratio, 0.57 [95% CI, 0.33-0.99]; P=0.04). In patients without ESUS, the respective incidence rates were 5.6% and 7.5% (hazard ratio, 0.72 [95% CI, 0.58-0.90]; P<0.01). The P value was 0.56 for the treatment × ESUS status interaction effect.

CONCLUSIONS

In this prespecified exploratory analysis, ticagrelor with aspirin was superior to clopidogrel with aspirin for preventing stroke at 90 days in patients with acute ischemic stroke or transient ischemic attack who carried CYP2C19 loss-of-function alleles and were classified as ESUS.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04078737.

Ischemic stroke and the emerging role of left atrial function

INTRODUCTION

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Emerging evidence suggests that left atrial (LA) dysfunction could play a role in the pathophysiology of ischemic stroke, as a possible contributor and as a predictive biomarker.

AREAS COVERED

This narrative review details the intricate relationship between LA function, atrial fibrillation (AF), and ischemic stroke. We discuss imaging techniques used to assess LA function, the mechanisms by which impaired LA function may contribute to stroke, and its potential as a prognostic marker of stroke.

EXPERT OPINION

There is a lack of evidence-based treatments of LA dysfunction in both primary and secondary stroke prevention. This is partly due to the lack of a practical clinical definition and unanswered questions concerning the clinical implications of LA dysfunction in patients without AF. Until such questions are resolved, addressing well-known cardiovascular risk factors, like hypertension and obesity, should be prioritized for preventing AF and ischemic stroke. These risk factors are closely tied to atrial remodeling, emphasizing the importance of targeting primary modifiable factors for preventing future morbidity and mortality.

The Usefulness of Outpatient Cardiac Telemetry in Patients with Cryptogenic Stroke

Introduction: Atrial fibrillation (AF), apart from non-stenotic supracardiac atherosclerosis and neoplastic disease, is the leading cause of cryptogenic stroke, including embolic stroke of un-determined source (ESUS). The aim of our study was to determine the prevalence of AF in ESUS patients based on 30-day telemetric heart rate monitoring initiated within three months after stroke onset. Another aim was to identify factors that increase the likelihood of detecting subsequent AF among ESUS patients. Material and Methods: patients with first-ever stroke classified as per the ESUS definition were eligible for this study. All patients underwent outpatient 30-day telemetric heart rate monitoring. Results: In the period between 2020 and 2022, 145 patients were included. The mean age of all qualified patients was 54; 40% of eligible patients were female. Six patients (4.14%), mostly male patients (4 vs. 2), were diagnosed with AF within the study period. In each case, the diagnosis related to a patient whose stroke occurred in the course of large vessel occlusion. Episodes of AF were detected between day 1 and 25 after starting ECG monitoring. Out of the analyzed parameters that increase the probability of, A.F.; only supraventricular extrasystoles proved to be an independent factor regarding an increased risk of AF [OR 1.046, CI 95% 1.016-1.071, p-value < 0.01]. Conclusions: The use of telemetry heart rhythm monitoring in an outpatient setting can detect AF in 4% of ESUS patients who have undergone prior diagnostic procedures for cardiogenic embolism. Supraventricular extrasystoles significantly increases the likelihood of AF detection in patients with ESUS within three months following stroke. Comorbid coronary artery disease, diabetes and hypertension, rather than a single-factor clinical burden, increase the likelihood of AF detection in older ESUS patients. ESUS in the course of large vessel occlusion is probably associated with an increased likelihood of cardiogenic embolism.

Imaging features for the identification of atrial fibrillation in cryptogenic stroke patients

BACKGROUND

Whether specific imaging aspects can be used to identify cryptogenic stroke (CS) patients with high risk of underlying atrial fibrillation (AF) remains unclear. The purpose of this study was to evaluate brain-imaging features in CS patients and their utility as AF predictors.

METHODS

The Nordic Atrial Fibrillation and Stroke study was a prospective observational study of CS and transient ischemic attack patients undergoing 12-month cardiac-rhythm monitoring, biomarker and clinical assessments. In this imaging sub-study, brain magnetic resonance imaging and computed tomography scans from 106 patients were assessed for acute and chronic ischemic lesions in relation to AF occurrence and included in a score to predict AF. Receiver operating characteristics (ROC) curve was used to evaluate the discriminative ability of the score and for its dichotomization for predictive model.

RESULTS

Age, periventricular white-matter hyperintensities (PVWMH), acute lesion size, and vessel occlusion were significantly associated with AF. Acute and chronic cortical infarcts as well as chronic cerebellar infarcts were numerically more frequent in the AF group than the non-AF group. A score consisting of six features (0-6 points) was proposed (age ≥ 65 years, chronic cortical or cerebellar lesions, acute cortical lesions, PVWMH ≥ 2 in Fazekas scale, vessel occlusion, and acute lesion size ≥ 10 mm). Area under ROC curve was 0.735 and a score of ≥ 3 points was a predictor of AF.

CONCLUSIONS

The suggested score was shown to identify CS patients with an increased risk of underlying AF.

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.

Thrombectomy in young adults with embolic stroke of undetermined source: Analysis of the Young ESUS study

OBJECTIVES

Embolic Stroke of Undetermined Source (ESUS) is a distinct stroke entity that disproportionately affects young adults. We sought to describe characteristics, workup and outcomes of young adult ESUS patients who underwent thrombectomy, and compare outcomes to those reported in different age groups.

MATERIALS AND METHODS

Young-ESUS is a multicenter longitudinal cohort study that enrolled consecutive patients aged 21-50 years at 41 stroke centers in 13 countries between 2017- 2019. Between-group comparisons were performed using Wilcoxon rank sum test for continuous variables or Fisher's exact test for binary variables. Distribution of functional outcomes after thrombectomy for our young adult cohort versus pediatric and older adult cohorts reported in the literature were described using the Kruskal-Wallis test.

RESULTS

Of 535 patients enrolled in Young-ESUS, 65 (12.1%) were treated with endovascular thrombectomy. Patients who underwent thrombectomy were more likely to undergo in-depth cardiac testing than those who did not, but cardiac abnormalities were not detected more often in this group. Among thrombectomy patients, 35/63 (55.6%) had minimal to no functional disability at follow up. When adjusted for age, stroke severity and IV alteplase, the odds of achieving favorable outcome did not differ between treated versus untreated patients.

CONCLUSIONS

Thrombectomy is not rare in young adults with ESUS. Despite extensive workup, cardiac abnormalities were not more prevalent in the thrombectomy group. More research to determine optimal workup, etiologic factors and favorable outcome of stroke across the lifespan is needed.

How Topographic Diffusion-Weighted Imaging Patterns can Predict the Potential Embolic Source

PURPOSE

To develop an imaging prediction model for patients with embolic stroke of undetermined source (ESUS), we investigated the association of topographic diffusion-weighted imaging (DWI) patterns with potential embolic sources (PES) identified by transesophageal echocardiography.

METHODS

From a total of 992 consecutive patients with embolic stroke, 366 patients with the ESUS group were selected. ESUS was defined as no atrial fibrillation (Af) within 24h from admission and no PES after general examination. Clinical variables include age (> 80years, 70-80 years), sex, vascular risk factors and left atrial diameter > 4 cm. Age, sex and vascular risk factors adjusted odds ratio of each DWI for the different PESs were calculated. DWI was determined based on the arterial territories. Middle cerebral arteries were divided into 4 segments, i.e., M1-M4. Moreover, M2 segments were subdivided into superior and inferior branches.

RESULTS

The 366 patients consisted of 168 with paroxysmal Af (pAf), 77 with paradoxical embolism, 71 with aortic embolism and 50 with undetermined embolism after transesophageal echocardiography. The variables adjusted odds ratio (OR) of internal carotid artery (OR: 12.1, p = 0.037), M1 (4.2, p = 0.001), inferior M2 (7.5, p = 0.0041) and multiple cortical branches (12.6, p < 0.0001) were significantly higher in patients with pAf. Striatocapsular infarction (12.5, p < 0.0001) and posterior inferior cerebellar artery infarcts (3.6, p = 0.018) were significantly associated with paradoxical embolism. Clinical variables adjusted OR of multiple small scattered infarcts (8.3, p < 0.0001) were significantly higher in patients with aortic embolism.

CONCLUSION

The associations of DWI with different PES have their distinctive characteristics and DWI along with clinical variables may help predict PES in patients with ESUS.

Altered left atrial metrics in patients with cryptogenic stroke: A systematic review and meta-analysis

BACKGROUND

There is no defined cause for cryptogenic stroke/embolic stroke of undetermined source (CS-ESUS). As atrial fibrillation (AF) develops in a significant proportion of these patients, it has been suggested that left atrial (LA) myopathy may predispose to CS-ESUS. We investigated alterations in echocardiographic measures of LA size and function in patients with CS-ESUS.

METHODS

A systematic literature review and meta-analysis was performed. PubMed, EMBASE, Cochrane Library, Web of Science and SCOPUS were searched for articles published between 1 January 1990 and 10 February 2023. All observational studies of adult CS-ESUS patients with LA volume or function measurements performed by transthoracic echocardiogram were included. Individual random effects meta-analyses were performed on LA measurements in the CS-ESUS patients using subgroup analysis of comparator groups.

RESULTS

We included 29 articles with 3927 CS-ESUS patients. Analysis of weighted mean differences showed CS-ESUS patients had altered LA structure and function parameters, with a larger maximum indexed LA volume, reduced LA emptying fraction and/or LA reservoir strain, compared to healthy controls and noncardioembolic stroke patients. Conversely, CS-ESUS patients had a smaller left atrium with better function, compared to cardioembolic stroke patients and CS-ESUS patients who subsequently developed atrial fibrillation.

CONCLUSIONS

LA volume and function are altered in CS-ESUS patients compared to healthy controls and other stroke aetiologies. An underlying atrial myopathy in a subset of CS-ESUS patients may be involved in both thrombogenesis and dysrhythmia (specifically AF). While LA functional assessment is not currently recommended following stroke, it may offer an opportunity for recurrent stroke risk stratification.

Risk scores for prediction of paroxysmal atrial fibrillation after acute ischemic stroke or transient ischemic attack: A systematic review and meta-analysis

Introduction

Detection of paroxysmal atrial fibrillation (PAF) is crucial for secondary prevention in patients with recent strokes of unknown etiology. This systematic review and meta-analysis assess the predictive power of available risk scores for detecting new PAF after acute ischemic stroke (AIS).

Methods

PubMed, Embase, Scopus, and Web of Science databases were searched until September 2023 to identify relevant studies. A bivariate random effects meta-analysis model pooled data on sensitivity, specificity, and area under the curve (AUC) for each score. The QUADAS-2 tool was used for the quality assessment.

Results

Eventually, 21 studies with 18 original risk scores were identified. Age, left atrial enlargement, and NIHSS score were the most common predictive factors, respectively. Seven risk scores were meta-analyzed, with iPAB showing the highest pooled sensitivity and AUC (sensitivity: 89.4%, specificity: 74.2%, AUC: 0.83), and HAVOC having the highest pooled specificity (sensitivity: 46.3%, specificity: 82.0%, AUC: 0.82). Altogether, seven risk scores displayed good discriminatory power (AUC ≥0.80) with four of them (HAVOC, iPAB, Fujii, and MVP scores) being externally validated.

Conclusion

Available risk scores demonstrate moderate to good predictive accuracy and can help identify patients who would benefit from extended cardiac monitoring after AIS. External validation is essential before widespread clinical adoption.

Cardioembolic Stroke: Past Advancements, Current Challenges, and Future Directions

Cardioembolic stroke accounts for over 20% of ischemic strokes and is associated with worse outcomes than other types of strokes. Atrial fibrillation (AF) is the most common risk factor for cardioembolic stroke. In this narrative review, we present an update about cardioembolic stroke mainly related to AF and atrial cardiopathy. Direct oral anticoagulants (DOACs) have revolutionized stroke prevention in patients with AF; however, their efficacy in preventing recurrent embolic stroke of unknown source remains uncertain. Various cardiac monitoring methods are used to detect AF, which is crucial for preventing stroke recurrence. DOACs are preferred over warfarin for AF-related stroke prevention; however, the timing of initiation after acute ischemic stroke is debated. Resuming anticoagulation after intracerebral hemorrhage in AF patients requires careful assessment of the risks. While catheter ablation may reduce the incidence of cardiovascular events, its effect on stroke prevention is unclear, especially in heart failure patients. Atrial cardiopathy is the emerging cause of embolic stroke of unknown source, which indicates atrial structural and functional disorders that can precede AF. Future research should focus on refining stroke risk prediction models, optimizing AF detection, understanding the roles of ablation and anticoagulation in stroke prevention, and establishing atrial cardiopathy as a therapeutic target, which could significantly reduce the burden of stroke.

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.

StrokeClassifier: ischemic stroke etiology classification by ensemble consensus modeling using electronic health records

Determining acute ischemic stroke (AIS) etiology is fundamental to secondary stroke prevention efforts but can be diagnostically challenging. We trained and validated an automated classification tool, StrokeClassifier, using electronic health record (EHR) text from 2039 non-cryptogenic AIS patients at 2 academic hospitals to predict the 4-level outcome of stroke etiology adjudicated by agreement of at least 2 board-certified vascular neurologists' review of the EHR. StrokeClassifier is an ensemble consensus meta-model of 9 machine learning classifiers applied to features extracted from discharge summary texts by natural language processing. StrokeClassifier was externally validated in 406 discharge summaries from the MIMIC-III dataset reviewed by a vascular neurologist to ascertain stroke etiology. Compared with vascular neurologists' diagnoses, StrokeClassifier achieved the mean cross-validated accuracy of 0.74 and weighted F1 of 0.74 for multi-class classification. In MIMIC-III, its accuracy and weighted F1 were 0.70 and 0.71, respectively. In binary classification, the two metrics ranged from 0.77 to 0.96. The top 5 features contributing to stroke etiology prediction were atrial fibrillation, age, middle cerebral artery occlusion, internal carotid artery occlusion, and frontal stroke location. We designed a certainty heuristic to grade the confidence of StrokeClassifier's diagnosis as non-cryptogenic by the degree of consensus among the 9 classifiers and applied it to 788 cryptogenic patients, reducing cryptogenic diagnoses from 25.2% to 7.2%. StrokeClassifier is a validated artificial intelligence tool that rivals the performance of vascular neurologists in classifying ischemic stroke etiology. With further training, StrokeClassifier may have downstream applications including its use as a clinical decision support system.

Machine Learning Modeling to Predict Atrial Fibrillation Detection in Embolic Stroke of Undetermined Source Patients

BACKGROUND

In patients with embolic stroke of undetermined source (ESUS), occult atrial fibrillation (AF) has been implicated as a key source of cardioembolism. However, only a minority acquire implantable cardiac loop recorders (ILRs) to detect occult paroxysmal AF, partly due to financial cost and procedural inconvenience. Without the initiation of appropriate anticoagulation, these patients are at risk of increased ischemic stroke recurrence. Hence, cost-effective and accurate methods of predicting AF in ESUS patients are highly sought after.

OBJECTIVE

We aimed to incorporate clinical and echocardiography data into machine learning (ML) algorithms for AF prediction on ILRs in ESUS.

METHODS

This was a single-center cohort study that included 157 consecutive patients diagnosed with ESUS from October 2014 to October 2017 who had ILR evaluation. We developed four ML models, with hyperparameters tuned, to predict AF detection on an ILR.

RESULTS

The median age of the cohort was 67 (IQR 59-74) years old and the median monitoring duration was 1051 (IQR 478-1287) days. Of the 157 patients, 32 (20.4%) had occult AF detected on the ILR. Support vector machine predicted for AF with a 95% confidence interval area under the receiver operating characteristic curve (AUC) of 0.736-0.737, multilayer perceptron with an AUC of 0.697-0.708, XGBoost with an AUC of 0.697-0.697, and random forest with an AUC of 0.663-0.674. ML feature importance found that age, HDL-C, and admitting heart rate were important non-echocardiography variables, while peak mitral A-wave velocity and left atrial volume were important echocardiography parameters aiding this prediction.

CONCLUSION

Machine learning modeling incorporating clinical and echocardiographic variables predicted AF in ESUS patients with moderate accuracy.

Differences between Acute Embolic and Atherosclerotic Middle Cerebral Artery Occlusion in Multiphase Arterial Spin-labeling Imaging

Arterial spin-labeling magnetic resonance imaging (ASL-MRI) is widely used for evaluating collateral development in patients with acute ischemic stroke (AIS). This study aimed to characterize the findings of multiphase ASL-MRI between embolic and atherosclerotic large vessel occlusion (LVO) to aid in the differential diagnosis. Among 982 patients with AIS, 44 who were diagnosed with acute, symptomatic, and unilateral occlusion of the horizontal segment of the middle cerebral artery (MCA) were selected and categorized into embolic stroke (ES) and atherosclerosis (AT) groups. Using ASL-MRI (postlabeling delay [PLD] of 1.5, 2.0, and 2.5 s) at admission, the ipsilateral to contralateral ratio (ICR) of the signal intensity and its time-course increasing rate (from PLD 1.5 to 2.0 and 2.5, ΔICR) were measured and compared between the two groups. The mean ICR was significantly higher in the AT group than in the ES group (AT vs. ES: 0.49 vs. 0.27 for ICR1.5, 0.73 vs. 0.32 for ICR2.0, and 0.92 vs. 0.37 for ICR2.5). The ΔICR of PLD 1.5-2.0 (ΔICR2.0) and 2.5 (ΔICR2.5) were also significantly higher in the AT group than in the ES group (AT vs. ES: 50.9% vs. 26.3% for ΔICR2.0, and 92.6% vs. 42.9% for ΔICR2.5). Receiver operating characteristic curves showed moderate-to-strong discriminative abilities of each ASL-MRI parameter in predicting MCA occlusion etiology. In conclusion, multiphase ASL-MRI parameters may aid in differentiating intracranial LVO etiology during the acute phase. Thus, it is applicable to AIS management.

Atrial Fibrillation After Patent Foramen Ovale Closure: Incidence, Pathophysiology, and Management

This comprehensive review explores the incidence, pathophysiology, and management of atrial fibrillation (AF) following percutaneous closure of patent foramen ovale (PFO). Although AF is considered a common adverse event post PFO closure, its incidence, estimated at <5%, varies based on monitoring methods. The review delves into the challenging task of precisely estimating AF incidence, given subclinical AF and diverse diagnostic approaches. Notably, a temporal pattern emerges, with peak incidence around the 14th day after closure and a subsequent decline after the 45th day, mimicking general population AF trends. The pathophysiological mechanisms behind post PFO closure AF remain elusive, with proposed factors including local irritation, device-related interference, tissue stretch, and nickel hypersensitivity. Management considerations encompass rhythm control, with flecainide showing promise, and anticoagulation tailored to individual risk profiles. The authors advocate for a personalized approach, weighing factors like age, comorbidities, and device characteristics. Notably, postclosure AF is generally considered benign, often resolving spontaneously within 45 days, minimizing thromboembolic risks. Further studies are required to refine understanding and provide evidence-based guidelines.

Long-Term Clinical Implications of High-Risk Cardiac Computed Tomography Findings in Patients With Acute Ischemic Stroke

BACKGROUND

Cardiac computed tomography (CT) acquired during the initial acute stroke imaging protocol (acute cardiac CT) is increasingly used to screen for cardioembolism, but information on the long-term clinical implications of its findings is lacking.

METHODS AND RESULTS

We performed a prospective, single-center cohort study in which consecutive patients with ischemic stroke underwent ECG-gated acute cardiac CT and were followed up for 2 years. The primary outcome was functional outcome assessed using the modified Rankin Scale. Secondary outcomes were death and occurrence of major adverse cardiovascular events (composite of recurrent ischemic stroke, myocardial infarction, and cardiovascular death). We compared patients with and without a high-risk structural source of embolism on acute cardiac CT. Of 452 included patients, 55 (12.2%) had a high-risk source of embolism, predominantly cardiac thrombi (38 patients) and signs of endocarditis (8 patients). Follow-up at 2 years was complete for 430 (95.1%) patients. Patients with a high-risk source of embolism had a worse functional outcome (median modified Rankin Scale, 6 [IQR, 2-6] versus 2 [IQR, 1-5]; adjusted common odds ratio, 2.92 [95% CI, 1.62-5.25]), increased mortality rate (52.7% versus 23.7%; adjusted hazard ratio [HR], 3.28 [95% CI, 1.94-5.52]), and major adverse cardiovascular events (38.9% versus 17.5%; adjusted HR, 3.20 [95% CI, 1.80-5.69]). A high-risk source of embolism was not associated with recurrent ischemic stroke (11.1% versus 9.6%; adjusted HR, 1.30 [95% CI, 0.49-3.44]).

CONCLUSIONS

Structural high-risk sources of embolism on acute cardiac CT in patients with ischemic stroke were associated with poor long-term functional outcome and occurrence of major adverse cardiovascular events but not with recurrent stroke.

Impact of an expanded reimbursement policy on utilization of implantable loop recorders in patients with cryptogenic stroke in Korea

BACKGROUND/AIMS

The reimbursement policy for cryptogenic stroke (CS) was expanded in November 2018 from recurrent strokes to the first stroke episode. No reports have demonstrated whether this policy change has affected trends in implantable loop recorder (ILR) utilization.

METHODS

We identified patients who received an ILR implant using the Korea Health Insurance Review and Assessment Service database between July 2016 and October 2021. Patients meeting all the following criteria were considered to have CS indication: 1) prior stroke history, 2) no previous history of atrial fibrillation or flutter (AF/AFL), and 3) no maintenance of oral anticoagulant for ≥4 weeks within a year before ILR implant. AF/AFL diagnosed within 3 years after ILR implant or before ILR removal was considered ILR-driven.

RESULTS

Among 3,056 patients, 1,001 (32.8%) had CS indications. The total ILR implant number gradually increased for both CS and non-CS indications and the number of CS indication significantly increased after implementing the expanded reimbursement policy. The detection rate for AF/AFL was 26.3% in CS patients over 3 years, which was significantly higher in patients implanted with an ILR within 2 months after stroke than those implanted later.

CONCLUSION

The expanded coverage policy for CS had a significant impact on the number of ILR implantation for CS indication. The diagnostic yield of ILR for AF/AFL detection seems better when ILR is implanted within 2 months than later. Further investigation is needed to demonstrate other clinical benefits and the optimal ILR implantation timing.

Antiphospholipid Syndrome and Antibodies Associated With Malignancy and Older Age: A Retrospective Study

BACKGROUND

Antiphospholipid syndrome (APLS) is an established cause of thrombosis and hypercoagulability. However, the clinical characteristics of those with APLS or patients with positive antiphospholipid antibodies (APLA) in the embolic stroke of undetermined source (ESUS) have not been well studied.

METHODS

A retrospective analysis was conducted between January 1, 2010, and December 31, 2020, across all three Mayo Clinic sites. Patients who were included in the study were tested for APLA and had a diagnosis of ESUS. Baseline characteristics, radiographic parameters, and outcome data were collected and compared between those who tested positive for APLS or had positive APLA and those who were negative.

RESULTS

A total of 206 patients were included in the study. Eight (4%) patients were diagnosed with APLS, and 21 (10%) patients had positive APLA. On comparing those with a diagnosis of APLS and those without, patients with APLS were found to be significantly older (75 years old ± 9 vs. 58 years old ± 14, p = 0.001) and were more likely to have a history of cancer (50% vs. 13%, p = 0.012). Those with positive APLA had similar findings of being older (67 years old ±13 vs. 58 years old ± 14 p = 0.003) and more likely to have a history of cancer (29% vs. 8.4% p = 0.027). Radiographically, those with APLS had a higher white matter disease burden (Fazekas score median 2 (IQR 1.5-3) vs. median 1 (IQR 1-2), p = 0.028).

CONCLUSION

Both APLS and positive APLA are associated with older age and a history of malignancy. These findings highlight the importance of considering a hypercoagulable evaluation even in the elderly ESUS population.

Cardiac Blood-Based Biomarkers of Myocardial Stress as Predictors of Atrial Fibrillation Development in Patients With Embolic Stroke of Undetermined Source/Cryptogenic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Undiagnosed atrial fibrillation (AF) is a major risk factor for stroke that can go unnoticed in individuals with embolic stroke of undetermined source (ESUS) or cryptogenic stroke (CS). Early detection is critical for stroke prognosis and secondary prevention. This study aimed to determine if blood biomarkers of myocardial stress can accurately predict AF in patients with ESUS/CS, which would allow the identification of those who would benefit from closer monitoring.

METHODS

In February 2023 we performed a systematic date-unrestricted search of three databases for studies on patients with ESUS/CS who were subsequently diagnosed with AF. We examined the relationships between AF and serum myocardial stress markers such as brain natriuretic peptide (BNP), N-terminal-pro-BNP (NT-proBNP), midregional proatrial natriuretic peptide, and troponin.

RESULTS

Among the 1,527 studies reviewed, 23 eligible studies involving 6,212 participants, including 864 with AF, were analyzed. A meta-analysis of 9 studies indicated that they demonstrated a clear association between higher NT-proBNP levels and an increased risk of AF, with adjusted and raw data indicating 3.06- and 9.03-fold higher AF risks, respectively. Lower NT-proBNP levels had a pooled negative predictive value of 91.7%, indicating the potential to rule out AF with an 8% false-negative rate.

CONCLUSIONS

Further research is required to fully determine the potential of biomarkers for AF detection after stroke, as results from previous studies lack homogeneity. However, lower NT-proBNP levels have potential in ruling out AF in patients with ESUS/CS. Combining them with other relevant biomarkers may enhance the precision of identifying patients who will not benefit from extended monitoring, which would optimize resource allocation and patient care.

Atrial fibrillation increases thrombogenicity of LVAD therapy

BACKGROUND

This study investigates the hypothesis that presence of atrial fibrillation (AF) in LVAD patients increases thrombogenicity in the left ventricle (LV) and exacerbates stroke risk.

METHODS

Using an anatomical LV model implanted with an LVAD inflow cannula, we analyze thrombogenic risk and blood flow patterns in either AF or sinus rhythm (SR) using unsteady computational fluid dynamics (CFD). To analyze platelet activation and thrombogenesis in the LV, hundreds of thousands of platelets are individually tracked to quantify platelet residence time (RT) and shear stress accumulation history (SH).

RESULTS

The irregular and chaotic mitral inflow associated with AF results in markedly different intraventricular flow patterns, with profoundly negative impact on blood flow-induced stimuli experienced by platelets as they traverse the LV. Twice as many platelets accumulated very high SH in the LVAD + AF case, resulting in a 36% increase in thrombogenic potential score, relative to the LVAD + SR case.

CONCLUSIONS

This supports the hypothesis that AF results in unfavorable blood flow patterns in the LV adding to an increased stroke risk for LVAD + AF patients. Quantification of thrombogenic risk associated with AF for LVAD patients may help guide clinical decision-making on interventions to mitigate the increased risk of thromboembolic events.

The Covert Impact of Chiari Network and Eustachian Valves on Stroke: A Scoping Review and Meta-Analysis

BACKGROUND

The role of Chiari network (CN) and Eustachian valves (EVs) in cardioembolic strokes is still unclear. There is inconsistency in the literature regarding clinical approach to these lesions to reduce stroke risk. We aimed to describe clinical presentation, neuroimaging and cardioimaging features, as well as management approaches for CN and EV in stroke context.

REVIEW SUMMARY

A systemic search was carried out using PubMed and Web of Science following PRISMA guidelines, Supplemental Digital Content 1 ( http://links.lww.com/NRL/A123 ). We retrieved 4 case-control studies, 2 cross sectional studies as well 8 case reports, with a total of 883 patients with a mean age of 44.6 years (±13.8). The combined prevalence of EV/CN in stroke-related patent foramen ovale (PFO) patients was 50% (95% CI: 31-68). With isolated prevalence for EV and CN of 43% (95% CI: 25-63), 18% (95% CI: 12-25), respectively. Patients with history of stroke had higher prevalence of EV/CN compared with controls odds ratio=2.45 (95% CI: 1.2-5, P <0.01). All case-control and cross-sectional studies defined EV/CN by transesophageal echocardiography or intracardiac cardiography. In the 8 case reports, 7 cases were diagnosed by transesophageal echocardiography, while only 1 case was diagnosed postmortem.

CONCLUSION

EV/CN are relatively common findings in stroke patients with PFO. While it appears that presence of EV/CN with a PFO increases the risk of cardioembolic stroke, they remain underrecognized. EV/CN should be considered as high-risk PFO features. There is a scarcity of research emphasizing their role in clinical decision making, especially PFO closure and antithrombotic therapy choice.

Embolic stroke of undetermined source: Focusing on atrial cardiopathy and patent foramen ovale

BACKGROUND

Atrial cardiopathy(AC) and patent foramen ovale (PFO) are two etiologies of embolic strokes of undetermined source (ESUS). We aimed to explore the relationship between them in ESUS.

METHODS

A total of 1146 participants were included from January 2019 to June 2022, which included the ESUS group and non-embolic stroke which includes LAA(large arterial atherosclerosis) + SAO(small artery occlusion) group. AC was defined as the presence of at least one of the following: PTFV1(P-wave terminal force in lead V1) > 4000 μV*ms in the electrocardiograms, NT-proBNP(N-terminal probrain natriuretic peptide) > 250 pg/mL in laboratory tests or LAD(left atrial diameter) > 3.8 cm for women and > 4.0 cm for men in cardiac ultrasound. The presence of PFO was assessed by transthoracic echocardiography, transcranial Doppler ultrasound, transesophageal echocardiography or cardiac MRI. PFO was considered pathogenic if the RoPE score was 7 to 10.

RESULTS

The prevalence of AC and PFO was higher in the ESUS group than the LAA + SAO group. The prevalence of AC was lower in ESUS patients with pathogenic PFO (37.9%) than those without PFO (68.4%) and with incidental PFO (64.0%) (p = 0.006). The prevalence of pathogenic PFO was lower in ESUS patients with AC than those without AC (6.0% vs. 17.8%, p = 0.006). The AUC(area under the curve) of PTFV1 for predicting ESUS was 0.724 [95%CI (0.686-0.762), p < 0.05)], indicating that PTFV1 the most valuable AC biomarker.

CONCLUSIONS

The prevalence of AC is inversely related to the prevalence of pathogenic PFO in ESUS patients. PTFV1 was the most valuable index to predict ESUS among the AC biomarkers.

Subtype-Specific Association of Mitochondrial DNA Copy Number With Poststroke/TIA Outcomes in 10 241 Patients in China

BACKGROUND

Mitochondrial DNA copy number (mtDNA-CN) is associated with the severity and mortality in patients with stroke, but the associations in different stroke subtypes remain unexplored.

METHODS

We conducted an observational prospective cohort analysis on patients with ischemic stroke or transient ischemic attack enrolled in the Third China National Stroke Registry. We applied logistic models to assess the association of mtDNA-CN with functional outcome (modified Rankin Scale score, 3-6 versus 0-2) and Cox proportional hazard models to assess the association with stroke recurrence (treating mortality as a competing risk) and mortality during a 12-month follow-up, adjusting for sex, age, physical activity, National Institutes of Health Stroke Scale at admission, history of stroke and peripheral artery disease, small artery occlusion, and interleukin-6. Subgroup analyses stratified by age and stroke subtypes were conducted.

RESULTS

The Third China National Stroke Registry enrolled 15 166 patients, of which 10 241 with whole-genome sequencing data were retained (mean age, 62.2 [SD, 11.2] years; 68.8% men). The associations between mtDNA-CN and poststroke/transient ischemic attack outcomes were specific to patients aged ≤65 years, with lower mtDNA-CN significantly associated with stroke recurrence in 12 months (subdistribution hazard ratio, 1.15 per SD lower mtDNA-CN [95% CI, 1.04-1.27]; P=5.2×10-3) and higher all-cause mortality in 3 months (hazard ratio, 2.19 [95% CI, 1.41-3.39]; P=5.0×10-4). Across subtypes, the associations of mtDNA-CN with stroke recurrence were specific to stroke of undetermined cause (subdistribution hazard ratio, 1.28 [95% CI, 1.11-1.48]; P=6.6×10-4). In particular, lower mtDNA-CN was associated with poorer functional outcomes in stroke of undetermined cause patients diagnosed with embolic stroke of undetermined source (odds ratio, 1.53 [95% CI, 1.20-1.94]; P=5.4×10-4), which remained significant after excluding patients with recurrent stroke (odds ratio, 1.49 [95% CI, 1.14-1.94]; P=3.0×10-3).

CONCLUSIONS

Lower mtDNA-CN is associated with higher stroke recurrence rate and all-cause mortality, as well as poorer functional outcome at follow-up, among stroke of undetermined cause, embolic stroke of undetermined source, and younger patients.

Mechanical thrombectomy for occlusion of the fenestrated middle cerebral artery M1 segment: A case report and review of the literature

It is impossible to predict underlying anomalies in acute large vessel occlusion and it could be a problem when performing mechanical thrombectomy (MT). We report a case of MT for occlusion of the fenestrated middle cerebral artery (MCA) M1 segment. A 49-year-old woman presented to our hospital with dysarthria and left hemiparesis. Acute ischemic stroke due to right occluded MCA was diagnosed. During performing emergent MT, a part of the M1 segment was revealed to be slit-shaped by digital subtraction angiography, suggesting a fenestrated MCA. The aspiration catheter could not be advanced through the narrow limb of the fenestration, and the distal thrombus was retrieved using a stent retriever, additionally. Postoperatively, the patient's symptoms improved without complications. When occlusion of the fenestrated MCA is suspected, it is necessary to consider converting the strategy from an aspiration catheter alone to the combined use of a stent retriever.

Enhanced diagnostic workup increases pathological findings in patients with acute ischaemic stroke: results of the prospective HEBRAS study

BACKGROUND

Stroke aetiology remains cryptogenic in a relevant proportion of patients with acute ischaemic stroke (AIS). We assessed whether enhanced diagnostic workup after AIS yields a higher rate of prespecified pathological findings compared with routine diagnostic care in-hospital.

METHODS

Hospitalised patients with AIS were prospectively enrolled in the investigator-initiated observational HEart and BRain Interfaces in Acute Ischaemic Stroke (HEBRAS) study at the Charité, Berlin, Germany. Patients with AIS without known atrial fibrillation (AF) underwent cardiovascular MR imaging (CMR), MR-angiography of the aortic arch and prolonged Holter-ECG monitoring on top of routine diagnostic care.

RESULTS

Among 356 patients with AIS (mean age 66 years, 37.6% female), enhanced workup yielded a higher rate of prespecified pathological findings compared with routine care (17.7% vs 5.3%; p<0.001). Consequently, fewer patients were classified as cryptogenic after enhanced diagnostic workup (38.5% vs 45.5%, p<0.001). Routine care included echocardiography in 228 (64.0%) patients. CMR was successfully performed in 292 (82.0%) patients and revealed more often a prespecified pathological finding compared with routine echocardiography (16.1% vs 5.3%). Furthermore, study-related ECG monitoring (median duration 162 hours (IQR 98-210)) detected AF in 16 (4.5%) patients, while routine monitoring (median duration 51 hours (IQR 34-74)) detected AF in seven (2.0%) patients.

CONCLUSIONS

Enhanced diagnostic workup revealed a higher rate of prespecified pathological findings in patients with AIS compared with routine diagnostic care and significantly reduced the proportion of patients with cryptogenic stroke.

TRIAL REGISTRATION NUMBER

NCT02142413.

Pediatric frequent relapsing nephrotic syndrome with multiple cerebral infarctions accompanied by patent foramen ovale and cerebral venous sinus thrombosis: a case report

BACKGROUND

Idiopathic nephrotic syndrome (NS) presents as a hypercoagulable state, of which thromboembolism (TE) is a well-known life-threatening complication. Although TE is more likely to occur in venous vessels than arterial vessels, arterial TE is important because it may cause after-effects, including tissue necrosis and cerebral infarction (CI); therefore, prompt diagnosis and appropriate treatment are required. We report a pediatric NS case with multiple CIs.

CASE PRESENTATION

A 14-year-7-month-old Japanese girl was diagnosed with frequent relapsing NS, accompanied by headache and disturbance of consciousness during the second relapse. Brain magnetic resonance imaging (MRI) and four-dimensional computed tomography revealed multiple CIs, vasogenic edema, and cerebral venous sinus thrombosis (CVST). The patient had no underlying thrombophilia other than hypercoagulability due to NS and prednisolone (PSL), and no cardiac arrhythmia; however, a right-to-left shunt through the patent foramen ovale (PFO) was observed with the Valsalva maneuver by echocardiography. Therefore, we assumed that a potential cause of multiple CIs might be an embolic stroke, caused by thrombosis formed from a hypercoagulable state due to NS and PSL treatment and reached through PFO. Antiplatelet and anticoagulant therapies were administered for TE. She was treated with PSL and mycophenolate mofetil (MMF) for NS. Rituximab (RTX) was administered to prevent NS relapse after complete remission (CR). She underwent transcatheter PFO closure at age 14 years and 9 months because we considered that the right-to-left shunt through the PFO would be one of the risks for recurrent cerebral embolism when NS relapses. One year after the onset of CIs, an MRI indicated that the CVST had resolved, leaving no neurological sequelae due to CI; therefore, anticoagulant therapy was discontinued. And then she has been in CR for NS with only MMF therapy.

CONCLUSIONS

CI is a serious complication in patients with NS. The pathogenesis of multiple CIs is various, including right-to-left shunt through PFO, in addition to the hypercoagulability due to NS. It is important to investigate and manage underlying risks such as PFO, besides preventing the relapses of NS by aggressive treatments using MMF and RTX, in patients with NS.

Long-term outcomes of patients with embolic stroke of undetermined source according to subtype

The prognosis of patients with embolic stroke of undetermined source (ESUS) may vary according to the underlying cause. Therefore, we aimed to divide ESUS into subtypes and assess the long-term outcomes. Consecutive patients with acute ischemic stroke who underwent a comprehensive workup, including transesophageal echocardiography and prolonged electrocardiography monitoring, were enrolled. We classified ESUS into minor cardioembolic (CE) ESUS, arteriogenic ESUS, two or more causes ESUS, and no cause ESUS. Arteriogenic ESUS was sub-classified into complex aortic plaque (CAP) ESUS and non-stenotic (< 50%) relevant artery plaque (NAP) ESUS. A total of 775 patients were enrolled. During 1286 ± 748 days follow-up, 116 major adverse cardiovascular events (MACE) occurred (4.2 events/100 patient-years). Among the ESUS subtypes, CAP ESUS was associated with the highest MACE frequency (9.7/100 patient-years, p = 0.021). Cox regression analyses showed that CAP ESUS was associated with MACE (hazard ratio 2.466, 95% confidence interval 1.305-4.660) and any stroke recurrence (hazard ratio 2.470, 95% confidence interval, 1.108-5.508). The prognosis of ESUS varies according to the subtype, with CAP ESUS having the worst prognosis. Categorizing ESUS into subtypes could improve patient care and refine clinical trials.

Clinical practice of continuous rhythm monitoring after embolic stroke of undetermined source

AIMS

Embolic stroke of undetermined source (ESUS) accounts for up to 20% of ischemic strokes annually. Undetected atrial fibrillation (AF) is one important potential underlying cause. For AF, oral anticoagulation has evolved as the most preferable means of secondary stroke prevention. To detect unrecognized paroxysmal AF, long-term ECG monitoring is required, and implantable cardiac monitors (ICM) appear most suitable. Yet, ICMs are particularly costly, implantation is invasive, and remote monitoring places a personnel burden on health care providers. Here, we use data from a large cohort of ESUS patients to systematically analyze the effort of ICM remote monitoring for AF diagnosis and the strain on health care providers.

METHODS AND RESULTS

From a prospective, single-center, observational ESUS registry, we analyzed all ICM-equipped patients post-ESUS (n = 172) between January 1st, 2018, and December 31st, 2019. Through January 2nd, 2023, 48 patients (27.9%) were diagnosed with AF by ICM remote monitoring. During follow-up, a total of 29,180 remote monitoring episodes were transmitted, of which 17,742 were alarms for AF. A systematic estimation of workload revealed that on average, 20.3 trained physician workhours are required to diagnose one patient with AF.

CONCLUSION

ICM remote monitoring is useful to diagnose AF in cohort of post-ESUS patients. However, the number of ICM alarms is high, even in a cohort at known high risk of AF and in whom AF detection is therapeutically consequential. Improved automated event classification, clear recommendations for ICM interrogation after AF diagnosis, and a careful patient selection for ICM monitoring are warranted.

Complex left appendage morphology is associated with Embolic Stroke of Undetermined Source

INTRODUCTION

Variations in the left atrial appendage (LAA) morphology are associated with different embolic risk in patients with atrial fibrillation (AF). Data are scarce regarding the association between LAA morphology and Embolic stroke of undetermined source (ESUS).

PATIENTS AND METHODS

Using cardiac computed tomography (CCT) scans, LAA morphology was categorized as either chicken wing (CW), cactus, windsock, or cauliflower. Furthermore, we examined the presence of large secondary lobes arising from the main lobe, considering their existence as indicative of a complex LAA morphology. LAA morphologies were compared between ESUS (n = 134) and AF patients (n = 120); and between ESUS patients with (n = 24) and without (n = 110) subsequent AF diagnosis during long-term follow-up.

RESULTS

ESUS patients had a significantly higher prevalence of cauliflower morphology compared to AF group (52% vs 34%, respectively, p = 0.01); however, no significant difference was found between the groups when categorizing LAA morphology to either CW or non-CW. ESUS patients had significantly higher prevalence of large secondary lobes compared with AF patients (50% vs 29%, respectively, p = 0.001). When comparing ESUS patients with and without AF diagnosis during follow-up (20-48 months of follow-up, median 31 months), there were no significant differences in the prevalence of the "classical" morphologies, but large secondary lobes were significantly more prevalent among those without subsequent AF diagnosis.

CONCLUSION

ESUS patients have a high prevalence of complex LAA morphology, which might be associated with an increased risk for thrombus formation even in the absence of AF.

MRI in the Evaluation of Cryptogenic Stroke and Embolic Stroke of Undetermined Source

Cryptogenic stroke refers to a stroke of undetermined etiology. It accounts for approximately one-fifth of ischemic strokes and has a higher prevalence in younger patients. Embolic stroke of undetermined source (ESUS) refers to a subgroup of patients with nonlacunar cryptogenic strokes in whom embolism is the suspected stroke mechanism. Under the classifications of cryptogenic stroke or ESUS, there is wide heterogeneity in possible stroke mechanisms. In the absence of a confirmed stroke etiology, there is no established treatment for secondary prevention of stroke in patients experiencing cryptogenic stroke or ESUS, despite several clinical trials, leaving physicians with a clinical dilemma. Both conventional and advanced MRI techniques are available in clinical practice to identify differentiating features and stroke patterns and to determine or infer the underlying etiologic cause, such as atherosclerotic plaques and cardiogenic or paradoxical embolism due to occult pelvic venous thrombi. The aim of this review is to highlight the diagnostic utility of various MRI techniques in patients with cryptogenic stroke or ESUS. Future trends in technological advancement for promoting the adoption of MRI in such a special clinical application are also discussed.

Chronic ischemic lesions and presence of patent foramen ovale in young adults with embolic stroke of undetermined source: Results of the young ESUS patient registry

BACKGROUND

Chronic ischemic lesions (CILs) are frequent findings in patients with acute ischemic stroke, but their phenotypes and relevance in young adults with embolic stroke of undetermined source (Y-ESUS) remains uncertain. We aimed to compare Y-ESUS patients with CIL to those without CIL and assessed the association of CIL and its phenotypes with the presence of patent foramen ovale (PFO).

METHODS

This prospective longitudinal, multicenter cohort study enrolled consecutive patients 50 years and younger with ESUS from October 2017 to October 2019 in 41 stroke research centers in 13 countries. Local investigators adjudicated presence and phenotypes of CIL on routine brain imaging (either magnetic resonance imaging (MRI) or computed tomography (CT)).

RESULTS

Overall, 535 patients were enrolled (mean age = 40.4 (standard deviation (SD) = 7.3) years, 238 (44%) female). CILs were present in 76/534 (14.2%) patients with a median count CIL count of 1.0 (interquartile range (IQR) = 1-2), 42/76 (55%) had at least one cortical phenotype and 38/76 (50%) at least one non-cortical phenotype. Y-ESUS with CIL were less often female (32% vs 47% in non-CIL Y-ESUS), were older (mean 43 vs 40 years), had more often hypertension (42% vs 19%), diabetes (17% vs 7%), and hyperlipidemia (34% vs 18%). CIL Y-ESUS were independently associated with lower stroke recurrence (relative risk (RR) = 0.17 (0.05-0.61)). In Y-ESUS with PFO, CILs were less frequent in probable pathogenic PFO than with probable non-pathogenic PFO (6.1% vs 30% p< 0.001).

CONCLUSION

One in seven Y-ESUS patients has additional CIL. CILs were associated with several vascular risk factors, lower probability of a pathogenic PFO, and lower stroke recurrence.

Management of ischaemic stroke survivors in primary care setting: the road to holistic care

The management of ischaemic stroke survivors is multidisciplinary, necessitating the collaboration of numerous medical professionals and rehabilitation specialists. However, due to the lack of comprehensive and holistic follow-up, their post-discharge management may be suboptimal. Achieving this holistic, patient-centred follow-up requires coordination and interaction of subspecialties, which general practitioners can provide as the first point of contact in healthcare systems. This approach can improve the management of stroke survivors by preventing recurrent stroke through an integrated post-stroke care, including appropriate Antithrombotic therapy, assisting them to have a Better functional and physiological status, early recognition and intervention of Comorbidities, and lifestyles. For such work to succeed, close interdisciplinary collaboration between primary care physicians and other medical specialists is required in a holistic or integrated way.

Tumor Embolic Stroke: The Importance of Pathological Assessment of Clots after Thrombectomy

While tumor emboli are a rare cause of stroke in cancer patients, they highlight the importance of gross observations and pathological assessments in the evaluation of clots. In this case report, a 70-year-old male with type 2 diabetes mellitus and coronary artery disease presented with acute left-sided weakness. He was clinically diagnosed with stroke and given alteplase at 1.5 h from last known normal. He then underwent CT angiography that showed right internal carotid artery occlusion and immediate thrombectomy. The recovered clot was white and lipid-like; due to its atypical appearance, it was sent for pathological assessment, where it was shown to bear features of malignancy. Subsequent imaging identified masses indicating malignancy in the left gluteus, right pleural hilum, and spine. Tumor embolic stroke is a rare pathology. Embolic diseases such as strokes and pulmonary embolisms are common in patients with cancer. Embolic stroke of undetermined source (ESUS) represents a significant portion of cancer strokes. Tumor emboli, though rare, may be an underappreciated source of ESUS in cancer patients. We intend for this case to demonstrate the value of pathological assessment for atypical thrombi as well as highlight the etiology of tumor embolic strokes.

Thin aortic arch plaque is associated with the development of atrial fibrillation for embolic stroke of undetermined source in patients with an insertable cardiac monitor

BACKGROUND AND OBJECTIVE

This study's objective is to investigate whether mild aortic arch plaque is associated with the development of atrial fibrillation (AF) in stroke patients with embolic stroke of undetermined source (ESUS) during the first year following the implantation of an insertable cardiac monitor (ICM).

METHODS

The participants in this cross-sectional observational study were consecutive patients with ESUS, even after transesophageal echocardiography. We assessed the relationship between the thickness of the participants' aortic arch plaque and AF detected after ICM implantation.

RESULTS

Of the 50 consecutive patients with ESUS enrolled in this study, 12 (24%) developed AF. We observed that thicker aortic arch plaque was associated with undetected AF (2.3 mm vs. 1.2 mm, p < 0.001). Aortic arch plaque thickness was independent associated with undetected AF (OR 54.00, 95% CI 2.706-1077.544, p = 0.009). When the cut-off value for aortic arch plaque thickness was 1.8 mm, the sensitivity and specificity were 71.1% and 91.7%, respectively (95% CI = 0.75-0.98, p < 0.001). Also, patients having both aortic arch plaque with a thickness < 1.8 mm and a CHADS2 score ≥ 4 were more likely to have detectable AF than no AF (88% vs. 12%, p < 0.001).

CONCLUSION

A thinner aortic arch plaque was associated with the development of AF. Patients with mild aortic plaques below 4 mm but ≥1.8 mm in thickness and without other high-risk features are less likely to have paroxysmal AF on ICM, and these plaques may be a possible source of embolism for their strokes.

Safety and efficacy of dynamic catheter-directed cerebral digital subtraction angiography for diagnosis of bowhunter syndrome spectrum disorders: A systematic review of the literature

INTRODUCTION

Dynamic catheter-directed cerebral digital subtraction angiography (dcDSA) is the gold standard for diagnosing dynamic vascular occlusion syndromes such as bowhunter syndrome (BHS). Nonetheless, concerns about its safety exist and no standardized protocols have been published to date.

METHODS

We describe our methodology and insights regarding the use of dcDSA in patients with BHS. We also perform a systematic literature review to identify cases of typical and atypical presentations of BHS wherein dcDSA was utilized and report on any procedural complications related to dcDSA.

RESULTS

Our study included 104 cases wherein dcDSA was used for the diagnosis of BHS. There were 0 reported complications of dcDSA. DcDSA successfully established diagnosis in 102 of these cases. Thirty-eight cases were deemed atypical presentations of BHS. Fourteen patients endorsed symptoms during neck flexion/extension. In eight cases, there was dynamic occlusion of bilateral vertebral arteries during a single maneuver. Three patients had multiple areas of occlusion along a single vertebral artery (VA). An anomalous entry of the VA above the C6 transverse foramen was observed in four patients. One patient had VA occlusion with neutral head position and recanalization upon contralateral lateral head tilt.

CONCLUSION

Our study highlights the safety and diagnostic benefits of dcDSA in characterizing the broad spectrum of BHS pathology encountered in clinical practice. This technique offers a powerful means to evaluate changes in cerebral blood flow and cervical arterial morphology in real time, overcoming the constraints of static imaging methods. Our findings pave the way for further studies on dcDSA to enhance cross-sectional imaging methods for the characterization of BHS and other dynamic vascular occlusion syndromes.

Predictors of atrial fibrillation detection in embolic stroke of undetermined source patients with implantable loop recorder

Background

Covert atrial fibrillation (AF) is a predominant aetiology of embolic stroke of undetermined source (ESUS). Evidence suggested that AF is more frequently detected by implantable loop recorder (ILR) than by conventional monitoring. However, the predictive factors associated with occult AF detected using ILRs are not well established yet. In this study we aim to investigate the predictors of AF detection in patients with ESUS undergoing an ILR.

Methods

This observational multi-centre study included consecutive ESUS patients who underwent ILR implantation. The infarcts were divided in deep, cortical infarcts or both. The infarction sites were categorized as anterior and middle cerebral artery, posterior cerebral artery with and without brainstem/cerebellum involvement. Multivariable logistic regression analysis was performed to investigate variables associated with AF detection.

Results

Overall, 3,000 patients were initially identified. However, in total, 127 patients who consecutively underwent ILR implantation were included in our analysis. AF was detected in 33 (26%) out of 127 patients. The median follow-up was 411 days. There were no significant differences in clinical characteristics and comorbidities between patients with and without AF detected. AF was detected more often after posterior cerebral artery infarct with brainstem/cerebellum involvement (p < 0.001) whereas less often after infarction in the anterior and middle cerebral artery (p = 0.021). Multivariable regression analysis demonstrated that posterior cerebral artery infarct with brainstem/cerebellum involvement was an independent predictor of AF detection.

Conclusion

Our study showed that posterior circulation infarcts with brainstem/cerebellum involvement are associated with AF detection in ESUS patients undergoing ILR. Larger prospective studies are needed to validate our findings.

Magnetic resonance imaging for diagnostic workup of embolic stroke of undetermined source: A systematic review

BACKGROUND

Embolic stroke of undetermined source (ESUS) refers to ischemic stroke where the underlying cause of thromboembolism cannot be found despite the recommended diagnostic workup. Unidentified source of emboli hinders clinical decision-making and patient management with detrimental consequences on long-term prognosis. The rapid development and versatility of magnetic resonance imaging (MRI) make it an appealing addition to the diagnostic routine of patients with ESUS for the assessment of potential vascular and cardiac embolic sources.

AIMS

To review the use of MRI in the identification of cardiac and vascular embolic sources in ESUS and to assess the reclassification value of MRI examinations added to the conventional workup of ESUS.

SUMMARY OF REVIEW

We reviewed the use of cardiac and vascular MRI for the identification of a variety of embolic sources associated with ESUS, including atrial cardiomyopathy, left ventricular pathologies, and supracervical atherosclerosis in carotid and intracranial arteries and in distal thoracic aorta. The additional reclassification after MRI examinations added to the workup of patients with ESUS ranged from 6.1% to 82.3% and varied depending on the combination of imaging modalities.

CONCLUSION

MRI techniques allow us to identify additional cardiac and vascular embolic sources and may further decrease the prevalence of patients with the diagnosis of ESUS.

Left Atrial Septal Pouch (LASP) and cryptogenic stroke risk: An updated systematic review and meta-analysis of observational studies

BACKGROUND

The left atrial septal pouch (LASP) is a small anatomical septal recess in the heart that has been linked with cardioembolic events. A systematic appraisal of the existing literature is necessary to establish a better understanding of the risk as studies continue to indicate a correlation between LASPs and cryptogenic strokes.

OBJECTIVES

To determine the level of association between the presence of LASP and the risk of developing cryptogenic stroke.

METHODS

We searched PubMed, EMBASE and Scopus for studies comparing the prevalence of LASP in patients with cryptogenic stroke against non-cryptogenic stroke control groups from inception till December, 2023. The Newcastle Ottawa scale was used for quality assessment and Comprehensive Meta-Analysis Version 3.3 was used for data analysis with odds ratio (OR) as the effect measure.

RESULTS

Our review included a total of 10 retrospective, observational studies published between 2010 to 2022. A total of 683 cases of cryptogenic strokes were identified, out of which 33.1 % (n = 271) were associated with a LASP. Among the non-cryptogenic stroke controls (n = 2641), LASP was present in 20.6 % cases (n = 476). The aggregate OR for cryptogenic stroke was 1.618 times greater than non-cryptogenic stroke (p < 0.001) among LASP cases, CONCLUSION: The presence of a septal pouch in the left atrium is significantly linked to a higher risk of developing cryptogenic strokes. As a potential site of thrombus formation and subsequent dislodgement, further large-scale studies are necessary to establish the guidelines for management and prophylaxis to prevent embolic events.

Cancer and arterial thrombosis: therapeutic options

A State of the Art lecture titled "Cancer and Arterial Thrombosis: Therapeutic Options" was presented at the International Society on Thrombosis and Haemostasis Congress in 2023. This State of the Art review delves into the complex relationship between cancer and arterial thromboembolism (ATE), encompassing acute coronary syndrome, ischemic strokes, and peripheral arterial disease. The burden of cancer-associated ATE is not well defined, but studies indicate elevated risks, particularly in the 6 months after a cancer diagnosis. Incidence varies among cancer subtypes, with lung cancer displaying the highest rates. Additionally, the pathophysiology of cancer-associated ATE involves a multifaceted interplay of cancer-induced hypercoagulopathy, cancer therapy-related thrombosis, and personal risk factor contributors. ATEs are clinically heterogeneous and in the context of cancer have particular mechanistic differences compared with ATE patients without cancer. This requires modifications in approach and tailored management considerations. Specific etiologies contributing to ATE, such as coronary vasospasm and non-bacterial-thrombotic endocarditis, need to be considered. The diagnosis of cancer alone usually does not contraindicate patients to standard guideline-based therapies for the management of ATE, although nuances in treatment may need to be considered in light of the underlying cancer. Atrial fibrillation in cancer patients further complicates the thrombotic landscape. Cancer patients with atrial fibrillation are at a higher risk of ATE, necessitating careful consideration of anticoagulation therapy as clinical benefits and bleeding risks need to be weighed. ATE may also be a presenting sign of underlying malignancy, which requires increased awareness and focused clinical evaluation for cancer in selected cases. Finally, we summarize relevant new data on this topic presented during the 2023 International Society on Thrombosis and Haemostasis Congress.

Management of patent foramen ovale; findings from a nationwide survey

OBJECTIVES

Several clinical trials have provided evidence supporting the transcatheter closure of patent foramen ovale (PFO) in selected patients following a cryptogenic stroke. However, it remains unknown to what extent these guidelines have been implemented in everyday clinical practice and the familiarity of physicians from different specialties with PFO closure. The aim of our nationwide survey is to explore the implementation of transcatheter PFO occlusion in Greek clinical practice.

MATERIALS AND METHODS

Attending level cardiologists, internal medicine physicians and neurologists involved in the management of PFO-related strokes working in Greece were invited to complete an online questionnaire. The questionnaire consisted of 19 questions and was designed to obtain comprehensive data on provider demographics, PFO characteristics, and specific clinical scenarios.

RESULTS

A total of 51 physicians (56.9 % cardiologists, 25.5 % neurologists and 17.6 % internal medicine physicians) completed the survey, resulting in a response rate of 53 %. Cardiologists, internal medicine physicians and neurologists agree on several issues regarding PFO closure, such as PFO closure as first line treatment, management of patients with DVT or prior decompression sickness, and post-closure antithrombotic treatment, but different approaches were reported regarding closure in patients with thrombophilia treated with oral anticoagulation (p=0.012) and implantable loop recorder placement for atrial fibrillation exclusion (p=0.029 and p=0.020).

CONCLUSIONS

Our findings show that cardiologists, internal medicine physicians and neurologists agree in numerous issues, but share different views in the management of patients with thrombophilia and rhythm monitoring duration. These results highlight the significance of collaboration among physicians from different medical specialties for achieving optimal results.

The relationship between atrial cardiopathy biomarkers and prognosis of patients with acute ischemic stroke after endovascular treatment

Thromboembolism is a possible consequence of underlying atrial cardiopathy, which can occur even before the onset of atrial fibrillation. Our objective was to examine the association between biomarkers of atrial cardiopathy and outcomes of acute ischemic stroke (AIS) following endovascular treatment (EVT). We conducted a retrospective study that collected data from patients with AIS who underwent EVT and compared the outcomes between those with and without atrial cardiopathy. Neurological function was assessed using the modified Rankin Scale (mRS), with an mRS score >2 indicating poor function at day 90. Additionally, we evaluated secondary consequences, including symptomatic intracerebral hemorrhage (sICH), early neurological deterioration (END), and malignant cerebral edema (MCE). Our study included 87 patients (77.6 ​% male; mean age 60.93 ​± ​12.47 years). Among these patients, 29 (33.3 ​%) had atrial cardiopathy, while the remaining 58 (66.7 ​%) did not. In the atrial cardiopathy group, 12 patients (41.4 ​%) had poor functional outcomes (mRS>2), compared to 19 (32.8 ​%) in the non-atrial cardiopathy group. We observed sICH in 22 (25.3 ​%) patients, END in 14 (16.1 ​%) patients, MCE in 11 (12.6 ​%) patients, and two (2.3 ​%) patients who died in the hospital. We found that patients with PTFV1>5000 ​μV/ms (OR: 8.39, 95 ​% CI: 1.43-105.95, P ​= ​0.02) and NT-proBNP>250 ​pg/mL (OR: 5.09, 95 ​% CI: 1.20-27.63, P ​= ​0.03) had significantly higher risk of END. After adjusting for covariates in the Firth logistic regression, we further found that atrial cardiopathy was significantly associated with END, as revealed by both univariate (OR: 6.31, 95 ​% CI: 1.42-59.87, P ​= ​0.01) and multivariable firth regression models (Modle 1, OR: 7.10, 95 ​% CI: 1.57-67.38, P ​< ​0.01; Modle 2, OR: 7.82, 95 ​% CI: 1.69, 76.36, P ​< ​0.01; Modle 3, OR: 8.59, 95 ​% CI: 1.72-91.70, P ​< ​0.01). Moreover, we observed that atrial cardiopathy was associated with an increased risk of END in AIS patients with large artery atherosclerosis (LAA) receiving EVT. Therefore, clinicians should consider atrial cardiopathy as a possible underlying cause of AIS in their patients. Further investigation is warranted to elucidate the relationship between atrial cardiopathy and AIS's occurrence, progression, and prognosis.

Magnetic Resonance Imaging-Guided Intravenous Thrombolysis in Cardioembolic Stroke Patients With Unknown Time of Onset - Subanalysis of the THAWS Randomized Control Trial

BACKGROUND

We investigated the clinical effect of intravenous thrombolysis using a magnetic resonance imaging (MRI)-guided approach in cardioembolic stroke (CE) patients with unknown time of onset.Methods and Results: This subanalysis of the THAWS trial assessed the efficacy and safety of alteplase 0.6 mg/kg in CE patients with unknown time of onset and showing diffusion-weighted imaging-fluid-attenuated inversion recovery mismatch. Patients were classified as CE and non-CE using the SSS-TOAST classification system during the acute period. The efficacy outcome was a modified Rankin Scale score of 0-1 at 90 days. In all, 126 patients from the THAWS trial were included in this study, of whom 45 (35.7%) were diagnosed with CE. In the CE group, a favorable outcome was numerically more frequent in the alteplase than control group (52% vs. 35%; adjusted odds ratio [aOR] 2.25; 95% confidence interval [CI] 0.50-9.99). However, in the non-CE group, favorable outcomes were comparable between the alteplase and control groups (44% vs. 55%, respectively; aOR 0.39; 95% CI 0.12-1.21). Treatment-by-cohort interaction for a favorable outcome was modestly significant between the CE and non-CE groups (P=0.069). In the CE group, no patients experienced symptomatic intracranial hemorrhage (ICH) or parenchymal hematoma Type II following thrombolysis.

CONCLUSIONS

When an MRI-guided approach is used, CE patients with unknown time of onset appear to be suitable candidates for thrombolysis.