Expert opinion of the Heart Rhythm Association of the Polish Cardiac Society and the Polish Neurological Society on evidence-driven implementation of implantable loop recorders in Poland

Implantable loop recorders (ILR) are considered increasingly helpful in diagnosing cardio-neurological conditions, especially if arrhythmic events are of high clinical importance but are unlikely to be captured by standard methods of electrocardiogram recording due to the low frequency of events and short duration of a single event. The compelling evidence from randomized trials and observational studies strongly supports ILR utilization in patients after cryptogenic stroke or transient ischemic attack and in patients with recurrent transient loss of consciousness of unknown origin. These two groups of patients are expected to gain the most from initiating ILR-driven clinically effective management strategies. Stroke or transient ischemic attack survivors with detected subclinical atrial fibrillation can be switched from antiplatelets to anticoagulants, whilst patients with recurrent syncope may avoid severe injuries and/or substantial impairment of their quality of life. This joint opinion of the Heart Rhythm Association of the Polish Cardiac Society and experts from the Polish Neurological Society summarizes the up-to-date rationale for using ILR in everyday clinical practice and describes the road map for implementing this technology in Poland. Special emphasis is placed on the most recent guidelines issued by both cardiological and neurological scientific societies.

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.

The usefulness of global longitudinal peak strain and left atrial volume index in predicting atrial fibrillation in patients with ischemic stroke

Introduction

Detection of atrial fibrillation (AF) is crucial for preventing recurrence in patients with ischemic stroke. We aimed to examine whether the left atrial volume index (LAVI) and global longitudinal peak strain (GLPS) are associated with AF in patients with ischemic stroke.

Methods

We prospectively analyzed 678 consecutive patients with ischemic stroke. LAVI and GLPS were assessed using three-dimensional transthoracic echocardiography with speckle-tracking imaging. Multiple logistic regression was used to evaluate the association of AF with LAVI and GLPS. To evaluate the predictive value of LAVI and GLPS for the presence of AF, we used optimism-corrected c-statistics calculated by 100 bootstrap repetitions and the net reclassification improvement (NRI).

Results

The mean patient age was 68 ± 13 years (men, 60%). Patients with AF (18%) were a higher LAVI (41.7 ml/m2 vs. 74.9 ml/m2, P < 0.001) and a higher GLPS than those without AF (-14.0 vs. -17.3, P < 0.001). Among the 89 patients classified with embolic stroke of unknown source, the probable cardioembolic group had higher GLPS (n= 17, -14.6 vs. -18.6, respectively; P= 0.014) than the other groups (n= 72). Adding GLPS to age, hypertension, and the LAVI significantly improved the NRI, with an overall NRI improvement of 6.1% (P= 0.03).

Discussion

The LAVI andGLPS with speckle-tracking imaging echocardiography may help identify patients with AF.

Predictive value of transesophageal echocardiography combined with contrast transthoracic echocardiography for embolic stroke of undetermined source

OBJECTIVE

In this study, we aimed to assess the predictive value of transesophageal echocardiography (TEE) combined with contrast transthoracic echocardiography (cTTE) for embolic stroke of undetermined source (ESUS).

METHODS

A total of 52 patients with ESUS were examined by TEE and cTTE. The detection rate of patent foramen ovale (PFO) and right-to-left shunt (RLS) grade were compared in patients with ESUS between cTTE alone and cTTE combined with TEE. The Risk of Paradoxical Embolism (RoPE) score, PFO diameter, and PFO length of patients with PFO-associated ESUS and non-PFO-associated ESUS were compared by cTTE alone and cTTE combined with TEE. The receiver operating characteristic (ROC) curve was utilized to determine the effect of RoPE score and PFO diameter on patients with PFO-associated ESUS.

RESULTS

The positive rate of PFO detected by cTTE alone (46.15%) was lower than that detected by cTTE combined with TEE (69.23%). The proportion of patients with RLS grade I + II + III detected by cTTE combined with TEE (69.23%) was higher than that detected by cTTE alone (46.15%). Both the RoPE score and PFO diameter were significantly greater in the patients with PFO-associated ESUS than in the patients with non-PFO-associated ESUS (p < .05). The combination of RoPE score and PFO diameter had the largest area under the ROC curve (AUC = 0.875), which was larger than the AUC alone of RoPE score (AUC = 0.819) and PFO diameter (AUC = 0.783) (p < .05).

CONCLUSION

The combination of cTTE and TEE is helpful to the diagnosis of ESUS patients caused by PFO and to judge the degree of RLS.

Diagnostic value of carotid intima-media thickness and clinical risk scores in determining etiology of ischemic stroke

BACKGROUND

In the general population, carotid intima-media thickness (CIMT) is associated with atherosclerosis as well as atrial fibrillation (AF). However, the extent to which CIMT might be of diagnostic value in clarifying stroke etiology is currently unclear.

METHODS

In this retrospective cohort study, we included 800 consecutive patients with acute ischemic stroke. We compared CIMT-values between stroke etiologies. The association between CIMT and cardioembolic stroke was investigated via logistic regression analysis adjusting for vascular risk factors. Receiver operating characteristic analyses were conducted to investigate the diagnostic value of CIMT in comparison to vascular risk factors and clinical AF risk scores (CHA2DS2VASc, HAVOC, and AS5F).

RESULTS

CIMT-values were highest in patients with cardioembolic or atherosclerotic stroke origin. CIMT was associated with newly diagnosed AF compared against cryptogenic strokes (crude odds ratio (OR) per 0.1 mm-increase of CIMT: 1.26 (95% confidence interval (CI): 1.13-1.41)). After adjustment for vascular risk factors, the effect of CIMT on AF-diagnosis, however, was weakened (adjusted OR: 1.10 (95% CI: 0.97-1.25)). The diagnostic value of CIMT for detection of AF (AUC: 0.60, 95% CI: 0.54-0.65) was outperformed by AF risk scores. Among the scores investigated, the AS5F-score yielded best accuracy and calibration to predict newly diagnosed AF (AUC: 0.71, 95% CI: 0.65-0.78).

CONCLUSIONS

CIMT may help in the diagnosis of stroke etiology. However, compared with vascular risk factors or clinical AF risk scores, CIMT does not provide substantial additional information on the risk of newly detected AF. Thus, stratification of AF risk based on scores, such as the AS5F, is advisable.

Recurrence of Cryptogenic (ESUS) Strokes in the First Year: Predictors and Outcome-A South Indian Study

Introduction

Around 9-25% of ischemic strokes are embolic stroke of undetermined source (ESUS) with an annual recurrence risk of 4.5-5%. Regarding ESUS, studies from India are limited. Here, we studied the prevalence of cryptogenic ESUS among stroke subtypes, recurrence risk and outcome at 1 year, and their predictors.

Materials and Methods

We performed a single-center study of ambispective nature. Patients above 18 years of age with a diagnosis of cryptogenic (ESUS) strokes from January 1, 2017, to December 31, 2020 (4 years), with a 1-year follow-up were recruited in our study. All the patients underwent neuroimaging computerised tomography/magnetic resonance tomography (CT/MRI) with angiography, electrocardiogram (ECG), transthoracic echo (TTE), and rhythm monitoring. Functional outcome was measured using the modified Rankin scale with scores 0-2 taken as good outcome.

Results

We had 234 (11.21% of total ischemic strokes) subjects satisfying the criteria for ESUS over the study period with a mean age of 58.2 ± 12.8 years. 46 patients had a history of stroke/transient ischemic attack (TIA) at admission. 9.4% had a recurrent event at 1 year. The most important neuroimaging predictor of recurrent strokes was multiple embolic followed by superficial watershed pattern. Around 10% had more than one marker of atrial cardiopathy positive. While the risk factors, coronary artery disease (CAD), and neuroimaging pattern showed an association with recurrent events at 1 year on bivariate analysis, only the latter two remained significant on multivariate analysis.

Conclusions

Our cohort of ESUS had a higher annual recurrence risk than reported before. Though vascular risk factors and ipsilateral vessel abnormalities were more in the recurrent ESUS group, it did not significantly affect the recurrence risk at 1 year. CAD and multiple embolic patterns on imaging showed an association with recurrent strokes, suggesting a possible cardiac substrate in our ESUS population as well.

Vulnerable plaque of the petrous internal carotid artery in embolic stroke of undetermined source

BACKGROUND AND PURPOSE

The association between nonstenotic plaque at the petrous internal carotid artery (ICA) and embolic stroke of undetermined source (ESUS) remains unknown. We aimed to test the hypothesis that the presence of a larger build-up of petrous plaque is more prevalent in the ipsilateral versus the contralateral side among ESUS patients without plaque in the intracranial and proximal ICA.

METHODS

From a total of 243 patients with ESUS and 160 patients with small-vessel disease (SVD) without proximal ICA plaque, we enrolled 88 ESUS and 103 SVD patients without ipsilateral nonstenotic intracranial and proximal ICA plaque in the present study. Targeting the petrous segment of the ICA on two sides, plaque burden including plaque thickness, lumen area, vessel area, wall area, and percentage of luminal stenosis, and composition features (presence/absence of the ruptured fibrous cap, ulcer plaque, thrombus, discontinuity of plaque surface [DPS], intraplaque hemorrhage and complicated plaque) were assessed by high-resolution magnetic resonance imaging.

RESULTS

We found a higher prevalence of petrous plaque thickness ≥3.5 mm ipsilateral versus contralateral to the stroke (25/88 [28.4%] vs. 12/88 [13.6%], odds ratio [OR] 3.60, 95% confidence interval [CI] 1.34-9.70), but this imbalance was not seen in SVD. In patients with plaque thickness ≥3.5 mm, the presence of DPS (OR 4.05, 95% CI 1.11-14.78) and complicated plaque (OR 5.00, 95% CI 1.10-22.82) was more closely related to an index ESUS, a finding that was not evident in the subgroup with petrous plaque <3.5 mm (p for interaction = 0.027).

CONCLUSIONS

The present study provided the first evidence supporting a potential etiological role of vulnerable petrous plaque in ESUS.

Reclassification and risk stratification of embolic stroke of undetermined source by ASCOD phenotyping

BACKGROUND

Common vascular diseases underlying stroke, including atherosclerosis, small-vessel disease (SVD), and cardioembolic pathology, can be present in patients with embolic stroke of undetermined source (ESUS), although these are not direct causes of stroke.

AIMS

To describe the frequency and degree of the three major diseases using atherosclerosis, SVD, cardiac pathology, other causes, and dissection (ASCOD) phenotyping and to assess their prognostic implications in ESUS.

METHODS

In this prospective observational study, 221 patients with ESUS within 1 week of onset were consecutively enrolled and followed up for 1 year. Vascular diseases associated with stroke were assessed using the ASCOD classification. The primary outcome was a composite of nonfatal stroke, nonfatal acute coronary syndrome, and vascular death.

RESULTS

Among 221 patients (mean age, 69.6 years; male, 59.7%), 135 (61.1%), 102 (46.2%), and 107 (48.4%) had any grade of atherosclerosis (A2 or A3), SVD (S3), and cardiac pathology (C2 or C3), respectively. ESUS patients graded as A2 or A3 (i.e. ipsilateral atherosclerotic plaque, contralateral ⩾ 50% stenosis, or aortic arch plaque) were at a significantly higher risk of composite vascular events than those graded as A0 (i.e. no atherosclerotic disease) (adjusted hazard ratio (95% confidence interval), 2.40 (1.01-5.72). No differences were observed in the event risk between patients with S3 (i.e. magnetic resonance imaging evidence of SVD) and S0 (i.e. no SVD) and between those with C2 or C3 (i.e. presence of any cardiac pathology) and C0 (i.e. no cardiac abnormalities).

CONCLUSIONS

Atherosclerotic diseases corresponding to ASCOD grade A2 or A3 were predictive of recurrent vascular events in ESUS patients. Reclassification of ESUS using ASCOD phenotyping provides important clues for risk prediction and may guide optimal management strategies.

Current perspectives on the clinical management of cryptogenic stroke

INTRODUCTION

Cryptogenic stroke is a heterogeneous entity defined as an ischemic stroke for which no probable cause is identified despite thorough diagnostic evaluation. Since about a quarter of all ischemic strokes are classified as cryptogenic, it is a commonly encountered problem for providers as secondary stroke prevention is guided by stroke etiology.

AREAS COVERED

In this review, the authors provide an overview of stroke subtype classification schemes and diagnostic evaluation in cryptogenic stroke. They then detail putative cryptogenic stroke mechanisms, their therapeutic implications, and ongoing research. This review synthesizes the available evidence on PubMed up to December 2022.

EXPERT OPINION

Cryptogenic stroke is an evolving concept that changes with ongoing research. Investigations are focused on improving our diagnostic capabilities and solidifying useful constructs within cryptogenic stroke that could become therapeutically targetable subgroups within an otherwise nonspecific entity. Advances in technology may help move specific proposed cryptogenic stroke mechanisms from undetermined to known source of ischemic stroke.

ADAMTS-13 activity in stroke of known and unknown cause: Relation to vascular risk factor burden

Background

The identification of the underlying mechanism in ischemic stroke has important implications for secondary prevention. A disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS-13) has antithrombotic properties and was repeatedly implicated in the pathophysiology of stroke. In this study, we, therefore, aimed to investigate whether ADAMTS-13 is associated with stroke etiology and the burden of vascular risk factors.

Methods

We determined ADAMTS-13 activity in two prospectively recruited stroke cohorts in the long-term course after the event. Cohort 1 (n = 88) consisted of patients who suffered a stroke due to embolic stroke of undetermined source (ESUS), cardioembolic stroke due to atrial fibrillation (AF), large-artery atherosclerosis, or small vessel disease. In cohort 2, patients with cryptogenic stroke and patent foramen ovale (PFO) scheduled for PFO closure (n = 38) were enrolled. As measures of vascular risk factor burden, the CHA₂DS₂VASC score, the Essen Stroke Risk Score (ESRS), and the Risk of Paradoxical Embolism (RoPE) score were calculated, as appropriate.

Results

ADAMTS-13 activity was lower in patients with AF-related stroke compared to patients with ESUS (p = 0.0227), which was, however, due to confounding by vascular risk factors. ADAMTS-13 activity inversely correlated with the ESRS (r = -0.452, p < 0.001) and CHA₂DS₂VASC (r = -0.375, p < 0.001) in cohort 1. In accordance with these findings, we found a positive correlation between ADAMTS-13 activity and the RoPE score in cohort 2 (r = 0.413, p = 0.010).

Conclusion

ADAMTS-13 activity is inversely correlated with the number of vascular risk factors across different stroke etiologies. Further study is warranted to establish ADAMTS-13 as a mediator of cerebrovascular risk.

Cancer-related stroke: Exploring personalized therapy strategies

BACKGROUND

Cancer and ischemic stroke are two common diseases that threaten human health and have become the main causes of death in the world. It is estimated that one-in-ten patients with ischemic stroke have concomitant cancer, and this incidence is expected to increase as improvements in medical technology extends the life expectancy of cancer patients.

DISCUSSION

Cancer-related stroke (CRS) refers to unexplained ischemic stroke in patients with active cancer that cannot be explained by current stroke mechanisms. Available evidence suggests that CRS accounts for 5-10% of embolic stroke of undetermined source (ESUS). Although the incidence of CRS is gradually increasing, its underlying pathogenesis remains unclear. Also, there is no consensus on acute treatment and secondary prevention of stroke.

CONCLUSION

In this review, we retrospectively analyzed the incidence, mechanisms of CRS, its potential as a new stroke subtype, options for acute treatment, secondary prevention strategies, and disease progression, with the aim of attempting to explore personalized therapy strategies.

Left Atrial Cardiomyopathy - A Challenging Diagnosis

Left atrial cardiomyopathy (LACM) has been an ongoing focus of research for several years. There is evidence that LACM is responsible for atrial fibrillation and embolic strokes of undetermined sources. Therefore, the correct diagnosis of LACM is of clinical importance. Various techniques, including electrocardiography, echocardiography, cardiac magnetic resonance imaging, computed tomography, electroanatomic mapping, genetic testing, and biomarkers, can both identify and quantify structural, mechanical as well as electrical dysfunction in the atria. However, the question arises whether these techniques can reliably diagnose LACM. Because of its heterogeneity, clinical diagnosis is challenging. To date, there are no recommendations for standardized diagnosis of suspected LACM. However, standardization could help to classify LACM more precisely and derive therapeutic directions to improve individual patient management. In addition, uniform diagnostic criteria for LACM could be important for future studies. Combining several parameters and relating them seems beneficial to approach the diagnosis of LACM. This review provides an overview of the current evidence regarding the diagnosis of LACM, in which several potential parameters are discussed and, consequently, a proposal for a diagnostic algorithm is presented.

Predictors of Recurrent Stroke After Embolic Stroke of Undetermined Source in the RE-SPECT ESUS Trial

Background

We sought to determine recurrent stroke predictors among patients with embolic strokes of undetermined source (ESUS).

Methods and Results

We applied Cox proportional hazards models to identify clinical features associated with recurrent stroke among participants enrolled in RE‐SPECT ESUS (Randomized, Double‐Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) trial, an international clinical trial evaluating dabigatran versus aspirin for patients with ESUS. During a median follow‐up of 19 months, 384 of 5390 participants had recurrent stroke (annual rate, 4.5%). Multivariable models revealed that stroke or transient ischemic attack before the index event (hazard ratio [HR], 2.27 [95% CI, 1.83–2.82]), creatinine clearance <50 mL/min (HR, 1.69 [95% CI, 1.23–2.32]), male sex (HR, 1.60 [95% CI, 1.27–2.02]), and CHA₂DS₂‐VASc ≥4 (HR, 1.55 [95% CI, 1.15–2.08] and HR, 1.66 [95% CI, 1.21–2.26] for scores of 4 and ≥5, respectively) versus CHA₂DS₂‐VASc of 2 to 3, were independent predictors for recurrent stroke.

Conclusions

In RE‐SPECT ESUS trial, expected risk factors previously linked to other common stroke causes were associated with stroke recurrence. These data help define high‐risk groups for subsequent stroke that may be useful for clinicians and for researchers designing trials among patients with ESUS.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120.

The characteristics of intracranial plaques of unilateral, anterior circulation embolic stroke of undetermined source: an analysis of different subtypes based on high-resolution imaging

BACKGROUND AND PURPOSE

To investigate the characteristics of non-stenotic intracranial plaque (NSIP) among embolic stroke of undetermined source (ESUS) subtypes by high-resolution magnetic resonance imaging (HR-MRI).

METHODS

we retrospectively enrolled consecutive patients with ESUS who were mandatory for HR-MRI. Based the location and arterial supply of the infarct, ESUS were categorized into three types: cortical ESUS, subcortical ESUS and mixed ESUS. The NSIP parameters including plaque location, morphology (plaque distribution, remodeling index and plaque burden) and composition (thick fibrous cap, discontinuity of plaque surface, intraplaque hemorrhage and complicated plaque) were evaluated among subtypes.

RESULTS

Among 243 patients, there were 87 (35.8%) cortical ESUS, 127 (52.3%) subcortical ESUS and 29 (11.9%) mixed ESUS. We found significant differences in plaque location (P < 0.001), plaque quadrant (P < 0.001), remodeling index (P < 0.001), plaque burden (P < 0.001), discontinuity of plaque surface (P < 0.001), intraplaque hemorrhage (P = 0.001) and complicated plaque (P < 0.001) of ipsilateral NISP among different ESUS subtypes, except for fibrous cap (P = 0.135). But we found no differences among contralateral NISP. In addition, the clinical characteristics of the differences among ESUS subtypes were striking, including age (P = 0.004), initial National Institute of Health Stroke Scale (P < 0.001), coronary artery disease (P = 0.039), serum urea (P = 0.011) and creatinine (P = 0.002).

CONCLUSION

This is the first report of significantly heterogeneous characteristics of ipsilateral NSIP and clinical findings among ESUS subtypes, which may suggest their different underlying mechanisms.

Classification of patients with embolic stroke of undetermined source in cardioembolic and non-cardioembolic profiles

BACKGROUND

It is currently thought that embolic stroke of undetermined source (ESUS) patients have diverse underlying hidden etiologies, of which cardioembolism is one of the most important. This subgroup of patients could theoretically benefit from oral anticoagulation, but it remains unclear if these of patients can be correctly identified from other ESUS-subgroups and which markers should be used. We aimed to determine whether a machine learning (ML) model could discriminate ESUS patients into cardioembolic and non-cardioembolic profiles using baseline demographic and laboratory variables.

METHODS

Based on a prospective registry of consecutive ischemic stroke patients submitted to acute revascularization therapies, a ML model was trained using data on age, sex and 11 selected baseline laboratory parameters of patients with known stroke etiology with the aim of correctly identifying patients with cardioembolic and non-cardioembolic etiologies. The resulting model was used to classify ESUS patients into either cardioembolic or non-cardioembolic profiles.

RESULTS

The ML model was able to distinguish patients with known stroke etiology into cardioembolic or non-cardioembolic with excellent accuracy (area under the curve = 0.82). When applied to ESUS patients, the model classified 40.3% of them as having cardioembolic profiles. ESUS patients with cardioembolic profiles were older, more frequently female, more frequently had hypertension, less frequently were active smokers, had higher CHA2DS2-VASc scores, and had more premature atrial complexes per hour.

CONCLUSIONS

A ML model based on baseline demographic and laboratory parameters was able to classify ESUS patients in cardioembolic and non-cardioembolic profiles and predicted that 40% of the ESUS patients have a cardioembolic profile.

Atrial Cardiopathy and Cryptogenic Stroke

Recent advances in pathophysiology suggest that a pathological atrial substrate can cause embolic stroke even in patients without atrial fibrillation (AF). This pathological condition is called “atrial cardiopathy”, which indicates atrial structural and functional disorders that can precede AF. The objective of this narrative review was to provide a current overview of atrial cardiopathy and cryptogenic stroke. We searched the PubMed database and summarized the recent findings of the identified studies, including the pathogenesis of atrial cardiopathy, biomarkers of atrial cardiopathy, relationship between atrial cardiopathy and cryptogenic stroke, and therapeutic interventions for atrial cardiopathy. Abnormal atrial substrate (atrial cardiopathy) that leads to AF can result in embolic stroke before developing AF, and may explain the source of cryptogenic stroke in some patients. Although there are several potential biomarkers indicative of atrial cardiopathy, P-wave terminal force in lead V1 (>5,000 μV^* ms), N-terminal pro-brain natriuretic peptide (>250 pg/ml), and left atrial enlargement are currently promising biomarkers for the diagnosis of atrial cardiopathy. Because the optimal combination and thresholds of biomarkers for diagnosing atrial cardiopathy remain uncertain, atrial cardiopathy represents a spectrum disorder. The concept of atrial cardiopathy appears to be most valuable as a starting point for therapeutic intervention to prevent stroke. Validation of the diagnosis of atrial cardiopathy and whether it can be used as a new therapeutic target for direct oral anticoagulants are currently being covered in the ARCADIA trial.

Unique Clinicopathologic Subclassifiers of Cryptogenic Cerebral Emboli

INTRODUCTION

Ipsilateral nonstenotic (<50%) internal carotid artery (ICA) plaque, cardiac atriopathy, and patent foramen ovale (PFO) may account for a substantial proportion of embolic stroke of undetermined source (ESUS).

METHODS

Consecutive stroke patients at our center (2019-2021) with unilateral, anterior circulation ESUS were categorized into the following mutually exclusive etiologies: (1) nonstenotic ipsilateral ICA plaque (NSP, ≥3mm in maximal axial diameter), (2) sex-adjusted mod-to-severe left atrial enlargement (LAE), (3) PFO, and (4) "occult ESUS" (patients who failed to meet criteria for these 3 groups). Descriptive statistics and multivariable logistic regression were used to model group characteristics.

RESULTS

Of 132 included patients, the median age was 65 (IQR 56-73), 74 (56%) of whom were White, and 54 (41%) were female. Twenty-one patients (16%) had NSP proximal to the infarct territory, 17 (13%) had LAE, 9 (7%) had a PFO, and 85 (64%) had no other mechanism. Patients with LAE were older (p=0.004), and had more frequent intracranial occlusions of the internal carotid and proximal middle cerebral artery (p=0.048), while tobacco use was most commonly found among patients with NSP (75%) when compared to other ESUS groups (p=0.02). Five of 9 patients with LAE who underwent outpatient telemetry had paroxysmal atrial fibrillation (56%), while zero patients with PFO or NSP had paroxysmal atrial fibrillation (p=0.005). Older age (adjusted OR [aOR] 1.05, 95%CI 1.03-1.07), coronary artery disease (aOR 3.22, 95%CI 1.61-6.44) and hypertension (aOR 2.16, 95%CI 1.14-4.06) were independently associated with LAE, while only tobacco use was associated with NSP when compared to other ESUS subclassifiers (OR 3.18, 95%CI 1.08-0.42). Age and tobacco use were both inversely associated with PFO (aOR 0.93, 95%CI 0.88-0.98, and aOR 0.10, 95%CI 0.02-0.90, respectively).

CONCLUSIONS

Certain clinical and radiographic features may be useful in predicting the proximal source of occult cerebral emboli, and can be used for cost-effective outpatient diagnostic testing.

Cryptogenic Stroke and Embolic Stroke of Undetermined Source: Risk Factors and Approaches for Detection of Atrial Fibrillation

BACKGROUND

Stroke is a problem worldwide because of its high mortality and disability rates. Almost 90% of strokes are ischemic, and more than half of the deaths are caused by an ischemic stroke. Most risk factors for stroke are manageable so that it can be avoided with proper prevention. Despite the success in determining the causes of stroke in recent years, selectively, the "culprit" causing stroke remains unsolved. In such cases, a diagnosis of undetermined etiology (cryptogenic stroke) or embolic stroke of undetermined source (ESUS) is generated, resulting the prevention of a recurrent cerebrovascular occurrence impossible. Atrial fibrillation (AF) can be a cause of stroke by causing blood clots in the chambers of the heart.

PURPOSE

The aim was to determine the optimal method of heart rate monitoring in patients with ischemic stroke, as methods and approaches for detecting AF are very diverse, but there is still no single opinion, which would be universal.

PROCEDURES

In our review, we consider epidemiology, risk factors for the stroke of undetermined etiology, as well as analytical methods for detecting heart rhythm disturbances in this category of patients.

FINDINGS

Atrial fibrillation (AF) is detected by thorough monitoring of heart rate of patients with cryptogenic stroke and ESUS can be diagnosed in up to 46% of patients. .

CONCLUSION

After AF detection, consideration should be given to prescribing anticoagulants, instead of antiplatelet agents, for the secondary prevention of stroke.

[Cryptogenic stroke management : where are we ?]

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

Distinction in Prevalence of Atherosclerotic Embolic Sources in Cryptogenic Stroke With Cancer Status

Background

Cerebrovascular diseases are common comorbidities in patients with cancer. Although active cancer causes ischemic stroke by multiple pathological conditions, including thromboembolism attributable to Trousseau syndrome, the relationship between stroke and inactive cancer is poorly known. The aim of this study was to elucidate the different underlying pathogeneses of cryptogenic stroke in active and inactive patients with cancer, with detailed investigation by transesophageal echocardiography.

Methods and Results

CHALLENGE ESUS/CS (Mechanisms of Embolic Stroke Clarified by Transesophageal Echocardiography for Embolic Stroke of Undetermined Source/Cryptogenic Stroke) registry is a multicenter registry including data of patients initially diagnosed as having cryptogenic stroke and undergoing transesophageal echocardiography. Patients were divided into active cancer, inactive cancer, and noncancer groups, and their clinical features were compared. Of the total 667 enrolled patients (age, 68.7±12.8 years; 455 men), 41 (6.1%) had active cancer, and 51 (7.5%) had a history of inactive cancer. On multinomial logistic regression analysis, infarctions in multiple vascular territories (odds ratio [OR], 2.73; 95% CI, 1.39–5.40) and CRP (C‐reactive protein) (OR, 1.10; 95% CI, 1.01–1.19) were independently associated with active cancer, whereas age (OR, 1.05; 95% CI, 1.01–1.08), contralateral carotid stenosis from the index stroke lesion (OR, 4.05; 95% CI, 1.60–10.27), calcification of the aortic valve (OR, 2.10; 95% CI, 1.09–4.05), and complicated lesion of the aortic arch (OR, 2.13; 95% CI, 1.11–4.10) were significantly associated with inactive cancer.

Conclusions

Patients with cancer were not rare in cryptogenic stroke. Although patients with active cancer had more multiple infarctions, patients with inactive cancer had more atherosclerotic embolic sources potentially causing arteriogenic strokes.

Registration

URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000032957.

Atrial Cardiomyopathy: An Emerging Cause of the Embolic Stroke of Undetermined Source

Nearly 30% of ischemic strokes have an unknown cause, which are referred to as cryptogenic strokes (CS). Imaging studies suggest that a large proportion of these patients show features that are consistent with embolism, and thus the term embolic stroke of undetermined source (ESUS) was proposed to describe these CS patients. Atrial cardiomyopathy predisposes to thrombus formation and thus embolic stroke even in the absence of atrial fibrillation (AF). This may provide a mechanistic link with ESUS, suggesting that anticoagulant therapy may be more beneficial than antiplatelet therapy in ESUS patients with atrial cardiomyopathy. The present review discusses the concept of atrial cardiomyopathy and ESUS and the relationship between them based on the mechanisms and clinical evidence, suggests that atrial cardiomyopathy may be a potential mechanism of ESUS, and highlights a theoretical basis that supports that anticoagulant therapy may be more applicable to ESUS patients with atrial cardiomyopathy and aims to help us better understand and identify the risk of ESUS, thereby improving the management of these patients in clinical practice.

Association of Major Adverse Cardiovascular Events in Patients With Stroke and Cardiac Wall Motion Abnormalities

Background

The association of cardiac wall motion abnormalities (CWMAs) in patients with stroke who have major adverse cardiovascular events (MACE) remains unclear. The purpose of this study was to estimate the 50‐month risk of MACE, including stroke recurrence, acute coronary events, and vascular death in patients with stroke who have CWMAs.

Methods and Results

We performed a retrospective analysis of prospectively collected acute stroke data (acute stroke and transient ischemic attack) over 50 months by electronic medical records. Data included demographic and clinical information, vascular imaging, and echocardiography data including CWMAs and MACE. Of a total of 2653 patients with acute stroke/transient ischemic attack, CWMA was observed in 355 (13.4%). In patients with CWMAs, the embolic stroke of undetermined source (50.7%) was the most frequent index stroke subtype and stroke recurrences (P=0.001). In multivariate Cox regression after adjustment for demographics, traditional risk, and confounding factors, CWMA was independently associated with a higher risk of MACE (adjusted hazard ratio [HR], 1.74; 95% CI, 1.37–2.21 [P=0.001]). Similarly, CWMA independently conferred an increased risk for ischemic stroke recurrence (adjusted HR, 1.50; 95% CI, 1.01–2.17 [P=0.04]), risk of acute coronary events (aHR, 2.50; 95% CI, 1.83–3.40 [P=0.001]) and vascular death (adjusted HR, 1.57; 95% CI, 1.04–2.40 [P=0.03]), in comparison to the patients with stroke without CWMA.

Conclusions

In a multiethnic cohort of ischemic stroke with CWMA, CWMA was associated with 1.7‐fold higher risks of MACE independent of established risk factors. Embolic stroke of undetermined source was the most common stroke association with CWMA. Patients with stroke should be screened for CWMA to identify those at higher risk of MACE.

Anticoagulation Therapy Reduces Recurrent Stroke in Embolic Stroke of Undetermined Source Patients With Elevated Coagulation Markers or Severe Left Atrial Enlargement

Background: The objective of this study was to evaluate if anticoagulation therapy reduces recurrent stroke in embolic stroke of undetermined source (ESUS) patients with left atrial enlargement (LAE) or abnormal markers of coagulation and hemostatic activity (MOCHA) compared to antiplatelet therapy.

Methods: ESUS patients from January 1, 2017, to June 30, 2019, underwent outpatient cardiac monitoring and the MOCHA profile (serum d-dimer, prothrombin fragment 1.2, thrombin–antithrombin complex, and fibrin monomer). Anticoagulation was offered to patients with abnormal MOCHA (≥2 elevated markers) or left atrial volume index 40 mL/m². Patients were evaluated for recurrent stroke or major hemorrhage at routine clinical follow-up. We compared this patient cohort (cohort 2) to a historical cohort (cohort 1) who underwent the same protocol but remained on antiplatelet therapy.

Results: Baseline characteristics in cohort 2 (n = 196; mean age = 63 ± 16 years, 59% female, 49% non-White) were similar to cohort 1 (n = 42) except that cohort 2 had less diabetes (43 vs. 24%, p = 0.01) and more tobacco use (26 vs. 43%, p = 0.04). Overall, 45 patients (23%) in cohort 2 initiated anticoagulation based on abnormal MOCHA or LAE. During mean follow-up of 13 ± 10 months, cohort 2 had significantly lower recurrent stroke rates than cohort 1 (14 vs. 3%, p = 0.009) with no major hemorrhages.

Conclusions: Anticoagulation therapy in a subgroup of ESUS patients with abnormal MOCHA or severe LAE may be associated with a reduced rate of recurrent stroke compared to antiplatelet therapy. A prospective, randomized study is warranted to validate these results.

Atrial cardiopathy in embolic stroke of undetermined source

INTRODUCTION

Atrial cardiopathy is one of the most common potential sources of thromboembolism for embolic stroke of undetermined source (ESUS). The study aims to investigate the incidence of atrial cardiopathy (defined by severe left atrial enlargement (sLAE) or elevated serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) > 250 pg/ml) in patients with ESUS and compare with other stroke subtypes.

METHODS

We retrospectively collected data of 936 consecutive patients with diffusion-weighted imaging-confirmed acute ischemic stroke. The incidence of atrial cardiopathy was examined in ESUS, large artery atherosclerosis (LAA), and small vessel disease (SVD) strokes. Clinical characteristics were compared between ESUS patients with atrial cardiopathy (AC-ESUS) and patients with atrial fibrillation-induced cardioembolism (AF-CE) stroke.

RESULTS

245 patients were diagnosed with ESUS, while others were diagnosed with LAA (n = 312), SVD (n = 258), and AF-CE (n = 121) strokes. The incidence of sLAE in ESUS patients was higher than in LAA or SVD group (5.3% vs. 1.6% and 1.2%, respectively, p = .005) and higher than in combined LAA/SVD group (5.3% vs. 1.4%, p = .001). The incidence of elevated serum NT-proBNP in ESUS patients was not statistically different from that in LAA or SVD group. Compared with patients with AF-CE stroke, AC-ESUS patients had milder manifestations, had less hemorrhagic transformation, had better short-term outcome, and had fewer in-hospital complications.

CONCLUSIONS

The incidence of sLAE was higher in ESUS patients than in patients with noncardioembolic strokes. AC-ESUS was milder when compared to AF-CE stroke.

Correlation between left atrial expansion index and stroke subtype: A 10-Year Follow-Up Study

PURPOSE

Although left atrial (LA) expansion index predicts cardiovascular events, its efficacy for predicting cerebral events is unknown.

METHODS

This study enrolled 2205 patients who had sinus rhythm after echocardiography in their first visit. LA expansion index was calculated as (Vol_max -Vol_min ) x100%/Vol_min , where Vol_max was defined as maximal LA volume and Vol_min as minimal LA volume. The study endpoint was ischemic stroke. Stroke subtype was classified as cardioembolic stroke (CE), noncardioembolic stroke with determined mechanism (NCE), or embolic stroke of undetermined source (ESUS).

RESULTS

Over a 10-year (mean 9.7 years) follow-up period, 128 (5.8%) participants reached endpoint, including 46 with CE, 33 with NCE, and 49 with ESUS. Regardless of stroke subtype, LA expansion index was lower in the event groups compared to the nonevent group. The lowest quartile of LA expansion index was associated with high CHA₂ DS₂ -VASc score at enrollment and more events, including CE, ESUS, atrial fibrillation (AF), heart failure, and all-cause mortality, relative to other quartiles. The LA expansion index was an independent predictor of CE (HR 0.82; 95% CI 0.723-0.912, per 10% increase in LA expansion index; P < .0001) and ESUS (HR 0.92; 95% CI 0.881-0.976, per 10% increase in LA expansion index; p 0.003). An LA expansion index <68% predicts the presence of AF after ESUS with 84% sensitivity and 70% specificity.

CONCLUSION

LA expansion index is useful for predicting CE and ESUS. It is also associated with AF, heart failure hospitalization, and all-cause mortality.

Recurrent Bilateral Strokes in a Patient Treated With Sipuleucel-T for Prostate Cancer

Sipuleucel-T is approved by the US Food and Drug Administration (FDA) for the treatment of castration-resistant prostate cancer (CRPC). Herein, we present a patient with recurrent bilateral embolic stroke who was on sipuleucel-T therapy for CRPC. Laboratory and imaging data didn’t reveal any source of embolic stroke. A focused history disclosed that the patient received two doses of sipuleucel-T before the first stroke and was advised not to receive his third dose. He reported no other episode of stroke at the six-month follow-up. This case highlights the importance of identifying sipuleucel-T as a potential cause of embolic stroke if the source is not detectable, as discontinuing the therapy can be beneficial. Physicians should evaluate patients for risk of stroke before starting the therapy to prevent future strokes.

Successful detection of covert paroxysmal atrial fibrillation due to insertable cardiac monitor in embolic stroke of undetermined source in a patient with situs inversus totalis

Insertable cardiac monitors in patients with situs inversus totalis can detect atrial arrhythmia as a cause of embolic stroke. It is important to premap the position of ICM in order to clearly visualize the P wave.

Intracranial Atherosclerotic Plaque as a Potential Cause of Embolic Stroke of Undetermined Source

BACKGROUND

Previous studies investigated the potential mechanism of embolic stroke of undetermined source (ESUS) from extracranial artery plaque, but there has been no study other than a case report on high-risk intracranial plaque in ESUS.

OBJECTIVES

The aim of this study was to investigate the issue by evaluating the morphology and composition of intracranial plaque in patients with ESUS and small-vessel disease (SVD) using 3.0-T high-resolution magnetic resonance imaging.

METHODS

Two hundred forty-three consecutive patients with ESUS and 160 patients with SVD-associated stroke between January 2015 and December 2019 were retrospectively enrolled. Multidimensional parameters involving the presence of plaque on both sides, including remodeling index (RI), plaque burden, presence of discontinuity of plaque surface, thick fibrous cap, intraplaque hemorrhage, and complicated American Heart Association type VI plaque at the maximal luminal narrowing site, were evaluated using intracranial high-resolution magnetic resonance imaging.

RESULTS

Among 243 patients with ESUS, the prevalence of intracranial plaque was much higher in the ipsilateral than the contralateral side (63.8% vs. 42.8%; odds ratio [OR]: 5.25; 95% confidence interval [CI]: 2.83 to 9.73), a finding that was not evident in patients with SVD (35.6% vs. 30.6%; OR: 2.14; 95% CI: 0.87 to 5.26; p = 0.134). Logistic analysis showed that RI was independently associated with ESUS in model 1 (OR: 2.329; 95% CI: 1.686 to 3.217; p < 0.001) and model 2 (OR: 2.295; 95% CI: 1.661 to 3.172; p < 0.001). RI alone with an optimal cutoff of 1.162, corresponding to an area under the curve of 0.740, had good diagnostic efficiency for ESUS.

CONCLUSIONS

The present study supports an etiologic role of high-risk nonstenotic intracranial plaque in ESUS.

Data-driven machine-learning analysis of potential embolic sources in embolic stroke of undetermined source

BACKGROUND AND PURPOSE

Hierarchical clustering, a common 'unsupervised' machine-learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data-driven machine-learning method, and explored variation in stroke recurrence between clusters.

METHODS

We used a hierarchical k-means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum-variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer.

RESULTS

Among 800 consecutive ESUS patients (43.3% women, median age 67 years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64-4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43-3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster.

CONCLUSIONS

This data-driven machine-learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease.

Predictive value of free fatty acid levels in embolic stroke of undetermined source: A retrospective observational study

The present study aimed to investigate the predictive value of free fatty acid (FFA) in embolic stroke of undetermined source (ESUS) according to the presence of potential embolic sources (PES) after extensive etiologic evaluation.This was a retrospective observational study based on a single-center registry from January 2011 to July 2017. Stroke subtypes were determined through laboratory findings, brain, and angiographic imaging, carotid ultrasonography, transthoracic echocardiography, and 24-hour Holter monitoring. If ESUS was suspected, transesophageal echocardiography was additionally performed. Patients were classified into ESUS with PES and ESUS without PES. PES included mitral annular calcification, mitral valve prolapse, patent foramen ovale, atrial septal aneurysm, spontaneous echo contrast, ventricular aneurysm, and high-risk plaques of aortic arch, or carotid bulb. We compared clinical and laboratory findings between the two groups.Of a total of 110 ESUS patients, 61 patients (55.5%) had no PES. Patients with ESUS without PES had higher levels of serum FFA, systolic blood pressure, diastolic blood pressure (DBP), and left atrial (LA) enlargement compared with those of ESUS with PES. Multivariable analysis demonstrated that the FFA level, DBP, and LA volume index were associated with ESUS without PES [odds ratio (OR) 1.038, 95% confidence interval (CI) 1.019-1.058 for FFA/10 μEq/L, OR 1.414, 95% CI 1.037-1.928 for DBP/10 mm Hg, and OR 1.073, 95% CI 1.009-1.141 for LA volume index].Higher levels of FFA, DBP, and LA volume index are associated with ESUS without PES, highlighting the need to identify the role of these markers in ESUS through further large-scale, multi-center and prospective studies.

Prolonged ECG with a novel recorder utilizing electrode belt and mobile device in patients with recent embolic stroke of undetermined source: A pilot study

BACKGROUND

Paroxysmal atrial fibrillation (pAF) is a major risk factor for ischemic stroke, but challenging to detect with routine short-term monitoring methods. In this pilot study, we present a novel method for prolonged ECG and screening for pAF in patients with a recent embolic stroke of unknown source (ESUS).

METHODS

Fifteen patients aged ≥ 50 years with a recent ESUS were assigned to wear an external electrode belt-based 1-lead ECG device (Beat2Phone) continuously for 2 weeks (wear time). The device was operated via a mobile phone application in nonhospital conditions. The primary outcome was patient adherence to monitoring. Secondary outcomes were incidence of new pAF, quality-wise comparison to Holter, and usability of the novel ECG monitoring method with Systems Usability Scale (SUS). We also performed a 24- to 48-hr comparison between simultaneous Beat2Phone ECG and a standard Holter in 6 patients.

RESULTS

Wear time of Beat2Phone device was over 80% in 5 (33.3%) patients, 50%-80% in 7 (46.6%) patients, and less than 50% in 3 (20%) patients. We detected pAF ≥ 30 s in 1 patient (6.7%). In the simultaneous monitoring with Beat2Phone and Holter, there were a total of 817 (out of 1979) analyzable periods of sinus rhythm or premature atrial or ventricular beats (Cohen's Kappa coefficient 0.92 ± 0.02 between Beat2Phone and Holter), and no pAF events. Beat2Phone ECG showed remarkable SUS scores in user evaluations (average score: 81.4 out of 100 on SUS).

CONCLUSIONS

Beat2Phone device was easy to use among ESUS patients and in optimal conditions provided high-quality 1-lead ECG signal for diagnosing pAF.

CLINICAL TRIAL REGISTRATION

The study was not registered, as it was a nonrandomized single-arm pilot study.

Prevalence of Non-Stenotic (<50%) Carotid Plaques in Acute Ischemic Stroke and Transient Ischemic Attack: A Systematic Review and Meta-Analysis

INTRODUCTION

Non-stenotic (<50%) carotid plaques have recently been recognized as a potential source of stroke. This meta-analysis aims to summarize the prevalence of non-stenotic carotid plaques in stroke patients in general and in patients with embolic stroke of undetermined source in particular.

METHODS

We performed a comprehensive systematic review of the literature and meta-analysis on acute ischemic stroke patients in whom carotid imaging was performed using the MEDLINE, Embase and Cochrane database, including studies published up to December 2019. Keywords were "stroke", "transient ischemic attack", "carotid", "plaque", "atherosclerosis" and "disease". Included studies had ≥10 patients with acute ischemic stroke and reported the prevalence of non-stenotic (<50%%stenosis) carotid plaques detected on any imaging modality.

RESULTS

We included forty-five studies (n = 18304 patients, 48.4% males, mean age 63.6 years) in our meta-analysis. Imaging modalities used were ultrasound (n = 26 studies), CT-angiography (n = 7), magnetic resonance-imaging (n = 8) and catheter angiography (n = 4). The overall prevalence of non-stenotic carotid plaques was 51% (95% CI: 43 - 59). 10 studies included mainly patients with embolic stroke of undetermined source (>50% of all patients). The pooled prevalence of non-stenotic carotid plaques in these studies was 55% (95% CI: 42 - 68). 23 studies explicitly reported ipsilateral non-stenotic carotid plaques, the pooled prevalence of which was 51% (95% CI: 45 - 59).

CONCLUSIONS

In this meta-analysis, non-stenotic carotid plaques were present in more than 50% of all acute ischemic stroke patients, with a slightly higher prevalence in ESUS patients. Given the potential role of non-stenotic carotid plaques in stroke etiology, particularly in ESUS, further research should aim to identify criteria that predict the stroke risk associated with non-stenotic carotid plaques.

Endarterectomy for symptomatic internal carotid artery web

OBJECTIVE

The carotid web (CW) is an underrecognized source of cryptogenic, embolic stroke in patients younger than 55 years of age, with up to 37% of these patients found to have CW on angiography. Currently, there are little data detailing the best treatment practices to reduce the risk of recurrent stroke in these patients. The authors describe their institutional surgical experience with patients treated via carotid endarterectomy (CEA) for a symptomatic internal carotid artery web.

METHODS

A retrospective, observational cohort study was performed including all patients presenting to the authors' institution with CW. All patients who were screened underwent either carotid artery stenting (CAS) or CEA after presentation with ischemic stroke from January 2019 to February 2020. From this sample, patients with suggestive radiological features and pathologically confirmed CW who underwent CEA were identified. Patient demographics, medical histories, radiological images, surgical results, and clinical outcomes were collected and described using descriptive statistics.

RESULTS

A total of 45 patients with symptomatic carotid lesions were treated at the authors' institution during the time period. Twenty patients underwent CAS, 1 of them for a CW. Twenty-five patients were treated via CEA, and of these, 6 presented with ischemic strokes ipsilateral to CWs, including 3 patients who presented with recurrent strokes. The mean patient age was 55 ± 12.6 years and 5 of 6 were women. CT angiography or digital subtraction angiography demonstrated the presence of CWs ipsilateral to the stroke in all patients. All patients underwent resection of CWs using CEA. There were no permanent procedural complications and no patients had stroke recurrence following intervention at the latest follow-up (mean 6.1 ± 4 months). One patient developed mild tongue deviation most likely related to retraction, with complete recovery at follow-up.

CONCLUSIONS

CEA is a safe and feasible treatment for symptomatic carotid webs and should be considered a viable alternative to CAS in this patient population.

Examining the evidence for PFO closure and novel oral anticoagulants for treatment of cryptogenic stroke

Introduction: There has been considerable study assessing the treatment of cryptogenic stroke (CS) recently. This review examines the role of patent foramen ovale (PFO) closure in CS, while also discussing the evidence for alternative medical therapies in disease treatment.Areas covered: PFO closure for treatment of CS has been assessed in 6 randomized controlled trials (RCTs). This review summarizes the background, results and limitations of these trials. Methodological and treatment-related differences in RCTs provide potential explanations for the discordance in outcomes observed between older (CLOSURE, PC, RESPECT-Early) and newer PFO closure trials (RESPECT-Late, CLOSE, REDUCE, DEFENSE-PFO). With regards to medical therapy for CS, two RCTs (NAVIGATE ESUS and RE-SPECT ESUS) did not show any benefit in recurrent stroke prevention with the use of novel oral anticoagulants (NOAC) compared with aspirin. Marked differences in baseline characteristics and rates of recurrent stroke between PFO closure and NOAC trials underlie the heterogeneous nature of CS.Expert commentary: In young patients with CS, PFO closure reduces the risk of recurrent stroke, with newer RCTs emphasizing the importance of identifying those with 'high-risk' PFO and the need for continued antiplatelet therapy. Additionally, treatment for CS should not be uniform but directed at disease-specific pathologies.

Clinical Features of Embolic Stroke of Undetermined Source

Background and Objective: One-third of ischemic strokes have no identifiable cause following standard evaluation. In 2014, researchers have proposed the concept of Embolic Stroke of Undetermined Source (ESUS). The purpose of this study was to report the clinical characteristics of ESUS and its difference from cardiogenic embolism (CE), large-artery atherosclerosis (LA), and small-artery occlusion lacunar (SA).

Methods: Acute ischemic stroke (AIS) patients admitted to the department of Beijing Haidian Hospital from January 2017 to December 2017 were prospectively and consecutively enrolled. Base-line characteristics were collected. Stroke etiologies were presented and compared. We compared the clinical features and infarct sites of patients with acute cerebral infarction of different etiologies.

Results: A total of 119 AIS patients were analyzed in the study. There were 33 (27.73%) cases in ESUS group, 11 (9.24%) cases in CE group, 45 (37.82%) cases in LAA group and 30 (25.21%) cases in SA group. There were significant differences between the ESUS group and the CE group in the NIHSS score [3 (1.5–5) vs. 6 (2–20), p = 0.007], Modified Rankin Score [19, (57.58) vs. 9, (81.82), p = 0.008], hemorrhagic transformation [0, (0) vs. 5, (45.45), p < 0.001], and left atrial diameter [37.09 ± 3.16 vs. 41.73 ± 5.00, p = 0.001]. ESUS group and LA group have different mRS scores [19, (57.58) vs. 42, (93.33), p < 0.001]. ESUS group and SA group have different mRS scores [19, (57.58) vs. 28, (93.33), p = 0.001]. During 1 year follow-up, there were 5 cases (15.15%) in ESUS group, 3 cases (27.27%) in CE group, 3 cases (6.67%) in LA group, and 1 case (3.33%) in SA group with ischemic stroke (cerebral infarction or transient ischemic attack).

Conclusion: ESUS is more similar to atherosclerotic cerebral infarction in clinical features, but the distribution of lesions is more similar to cardiogenic embolism, suggesting that the pathogenesis of ESUS needs to be further explored.

Catch-up-ESUS - follow-up in embolic stroke of undetermined source (ESUS) in a prospective, open-label, observational study: study protocol and initial baseline data

INTRODUCTION

So far there is no uniform, commonly accepted diagnostic and therapeutic algorithm for patients with embolic stroke of undetermined source (ESUS). Recent clinical trials on secondary stroke prevention in ESUS did not support the use of oral anticoagulation. As ESUS comprises heterogeneous subgroups including a wide age-range, concomitant patent foramen ovale (PFO), and variable probability for atrial fibrillation (AF), an individualised approach is urgently needed. This prospective registry study aims to provide initial data towards an individual, structured diagnostic and therapeutic approach in ESUS patients.

METHODS AND ANALYSIS

The open-label, investigator-initiated, prospective, single-centre, observational registry study (Catch-up-ESUS) started in 01/2018. Consecutive ESUS patients ≥18 years who give informed consent are included and will be followed up for 3 years. Stratified by age <60 or ≥60 years, the patients are processed following a standardised diagnostic and treatment algorithm with an interdisciplinary design involving neurologists and cardiologists. Depending on the strata, patients receive a transesophageal echocardiogram; all patients receive an implantable cardiac monitor. Patients <60 years with PFO and without evidence of concomitant AF are planned for PFO closure within 6 months after stroke. The current diagnostic and therapeutic workup of ESUS patients requires improvement by both standardisation and a more individualised approach. Catch-up-ESUS will provide important data with respect to AF detection and PFO closure and will estimate stratified stroke recurrence rates after ESUS.

ETHICS AND DISSEMINATION

The study has been approved by the responsible ethics committee at the Ludwig Maximilian University, Munich, Germany (project number 17-685). Catch-Up-ESUS is conducted in accordance with the Declaration of Helsinki. All patients will have to give written informed consent or, if unable to give consent themselves, their legal guardian will have to provide written informed consent for their participation. The first observation period of the registry study is 1 year, followed by the first publication of the results including follow-up of the patients. Further publications will be considered according the predefined individual follow-up dates of the stroke patients up to 36 months.

TRIAL REGISTRATION NUMBER

Clinicaltrialsregister.gov registry (NCT03820375).

Impaired Endothelial Function in Embolic Stroke of Undetermined Source

BACKGROUND

Impairment of endothelial function is associated with atherosclerosis and atrial fibrillation, and could underlie several types of ischemic stroke. Embolic stroke of undetermined source (ESUS) recently attracted much attention as the major cause of cryptogenic stroke. This study aimed to clarify the endothelial function of patients with ESUS.

METHODS AND RESULTS

Between 2015 September and July 2017 July, we used flow-mediated vasodilation (FMD) test to evaluate vascular endothelial function in 182 patients with any vascular risk factors or a history of cerebrovascular events. The subject group was classified into the No Stroke group and 5 stroke subtype groups, large artery atherosclerosis (LAA), cardiogenic embolism (CE), small vessel disease (SVD), ESUS, and others (Other). Endothelial function was expressed as percentage increase in brachial vessel diameter (%FMD) after the interruption of blood flow with mechanical compression for 5 minutes. Mean FMD in the No stroke, LAA, CE, SVD, ESUS and Other groups were 7.03 ± 2.14%, 5.02 ± 2.75%, 4.97 ± 1.62%, 5.19 ± 2.67%, 3.55 ± 1.42%, and 6.55 ± 3.50%, respectively. After the adjustment for confounding factors, FMD was significantly lower in the ESUS group than in the No stroke, SVD, and Other groups. FMD tended to be lower in the ESUS group than in the LAA and CE groups, but the difference was not significant.

CONCLUSIONS

Endothelial function was impaired in patients with ESUS and may underlie its pathophysiology.

Clinical and Neuroimaging Characteristics in Embolic Stroke of Undetermined versus Cardioembolic Origin: A Population-Based Study

BACKGROUND AND PURPOSE

Evidence suggests that cardioembolism represents the underlying mechanism in the minority of embolic strokes of undetermined source (ESUS). In this population-based study, we sought to compare the clinical and imaging characteristics as well as outcomes in patients with ESUS and cardioembolic stroke (CE).

METHODS

We included consecutive patients with first-ever ischemic stroke (IS) from the previously published population-based Evros-Stroke-Registry identified as ESUS or CE according to standardized criteria. Baseline characteristics, admission NIHSS scores, cerebral edema, hemorrhagic transformation, stroke recurrence, functional outcomes (determined by modified Rankin Scale [mRS] scores), and mortality rates were recorded during the 1-year follow-up period.

RESULTS

We identified 21 ESUS (3.7% of IS) and 211 CE (37.1% of IS) cases. Patients with ESUS were younger (median age: 68 years [interquartile range [IQR]: 61-75] vs 80 years [IQR: 75-84]; P < .001), had lower median admission NIHSS scores (4 points [IQR: 2-8] vs 10 points [IQR: 5-17]; P < .001), and lower prevalence of cerebral edema on neuroimaging studies (0 vs. 33.3%, P = .002). Functional outcomes were more favorable in ESUS at 28 (median mRS score: 2 [IQR: 1-3] vs 4 [IQR: 4-5]; P < .001), 90 (median mRS score: 1 [IQR: 0-2] vs 4 [IQR: 3-5]; P < .001), and 365 days (median mRS score: 1 [IQR: 0-2] vs 4 [IQR: 2-4]; P < 0.001). At 1-year, the mortality rate was lower in ESUS (0% [95% confidence interval [CI]: 0-13.5%] vs 34.6% [95% CI: 28.2-41.0%]; P < .001); the 1-year recurrent rate was also lower numerically (0% [95% CI: 0-13.5%] vs 9.5% [95% CI: 5.5-13.4%]; P = .140) but this difference failed to reach statistical significance due to the small study population.

CONCLUSIONS

The clinical and neuroimaging profiles as well as clinical outcomes vary substantially between ESUS and CE indicating different underlying mechanisms.

Prevalence and Overlap of Potential Embolic Sources in Patients With Embolic Stroke of Undetermined Source

Background

We aimed to assess the prevalence and degree of overlap of potential embolic sources (PES) in patients with embolic stroke of undetermined source (ESUS).

Methods and Results

In a pooled data set derived from 3 prospective stroke registries, patients were categorized in ≥1 groups according to the PES that was/were identified. We categorized PES as follows: atrial cardiopathy, atrial fibrillation diagnosed during follow‐up, arterial disease, left ventricular disease, cardiac valvular disease, patent foramen ovale, and cancer. In 800 patients with ESUS (43.1% women; median age, 67.0 years), 3 most prevalent PES were left ventricular disease, arterial disease, and atrial cardiopathy, which were present in 54.4%, 48.5%, and 45.0% of patients, respectively. Most patients (65.5%) had >1 PES, whereas only 29.7% and 4.8% of patients had a single or no PES, respectively. In 31.1% of patients, there were ≥3 PES present. On average, each patient had 2 PES (median, 2). During a median follow‐up of 3.7 years, stroke recurrence occurred in 101 (12.6%) of patients (23.3 recurrences per 100 patient‐years). In multivariate analysis, the risk of stroke recurrence was higher in the atrial fibrillation group compared with other PES, but not statistically different between patients with 0 to 1, 2, or ≥3 PES.

Conclusions

There is major overlap of PES in patients with ESUS. This may possibly explain the negative results of the recent large randomized controlled trials of secondary prevention in patients with ESUS and offer a rationale for a randomized controlled trial of combination of anticoagulation and aspirin for the prevention of stroke recurrence in patients with ESUS.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02766205.

Statement by a Working Group conceived by the Polish National Consultants in Cardiology and Neurology addressing the use of implantable cardiac monitors in patients after ischaemic embolic stroke of undetermined source

INTRODUCTION

Stroke remains one of the main causes of death and the most common cause of long-term disability in adults. Embolic strokes of undetermined source (ESUS) amount to a significant proportion of all ischaemic strokes. Detection of atrial fibrillation (AF) in this group of patients would allow for a major therapeutic decision to switch from antiplatelets to oral anticoagulants and therefore significantly reduce the risk of recurrence.

STATE OF THE ART

Current technology allows long-term continuous ECG monitoring with different systems, including implantable cardiac monitors (ICM). However, in Poland lack of reimbursement does not allow their use in everyday clinical practice.

CLINICAL IMPLICATIONS

This is a statement by a Working Group conceived by the Polish National Consultants in Cardiology and Neurology addressing the use of ICM in patients after ischaemic embolic strokes of undetermined source. The aim was to develop reasonable and comprehensive guidance on how to select and manage candidates for ICM in order to obtain the maximum benefit for Polish public health.

FUTURE DIRECTIONS

This expert opinion is not intended as a guideline but it provides advice as to how to optimise the potential use of ICM in patients after ESUS in the Polish setting.

Continuous 4-week ECG monitoring with adhesive electrodes reveals AF in patients with recent embolic stroke of undetermined source

BACKGROUND

Atrial fibrillation (AF) frequently escapes routine stroke workup due to its unpredictable and often asymptomatic nature, leaving a significant portion of patients at high risk of recurrent stroke. Recent trials emphasized continuous electrocardiogram (ECG) monitoring in the detection of occult AF. We screened AF in patients meeting the embolic stroke of unknown source (ESUS) criteria using an external miniaturized recorder with an adhesive electrode.

METHODS

Patients aged ≥50 with recent ESUS were prospectively screened and assigned to wear a 1-lead ECG device capable to record continuous ECG for up to 4 weeks. Electrodes were replaced every 3-4 days. Primary outcome was proportion of patients completing at least 80% of monitoring. Secondary outcome measures included incidence of AF and initiation of oral anticoagulation therapy after AF detection.

RESULTS

Fifty-seven patients were monitored (mean age 64.5 ± 8.2 years, median delay from stroke to the start of monitoring 8 days, IQR 4-44). Of these, 51 patients (89.5%) completed at least 80% of the desired monitoring period. We detected AF ≥30 s in seven patients (12.3%), all of whom initiated anticoagulation therapy. Atrial fibrillation was revealed in six patients (85.7%) within the first week of monitoring. Compared to patients without AF, patients with AF were older (70.6 ± 5.1 vs. 63.6 ± 8.3 years, p < 0.011) and more obese (body mass index 30.0 ± 3.4 vs. 26.6 ± 4.6, p < 0.039).

CONCLUSIONS

Prolonged ECG monitoring with an external device using adhesive electrodes is feasible in ESUS patients, since nine out of ten patients used the device appropriately and AF was detected in one out of eight patients.

Left Atrial Appendage Morphology and Embolic Stroke of Undetermined Source: A Cross-Sectional Multicenter Pilot Study

BACKGROUND

The left atrial appendage (LAA) is the main source of thrombus in atrial fibrillation, and there is an association between non-chicken wing (NCW) LAA morphology and stroke. We hypothesized that the prevalence of NCW LAA morphology would be higher among patients with cardioembolic (CE) stroke and embolic stroke of undetermined source (ESUS) than among those with noncardioembolic stroke (NCS).

METHODS

This multicenter retrospective pilot study included consecutive patients with ischemic stroke from 3 comprehensive stroke centers who previously underwent a qualifying chest computed tomography (CT) to assess LAA morphology. Patients underwent inpatient diagnostic evaluation for ischemic stroke, and stroke subtype was determined based on ESUS criteria. LAA morphology was determined using clinically performed contrast enhanced thin-slice chest CT by investigators blinded to stroke subtype. The primary predictor was NCW LAA morphology and the outcome was stroke subtype (CE, ESUS, NCS).

RESULTS

We identified 172 patients with ischemic stroke who had a clinical chest CT performed. Mean age was 70.1 ± 14.3 years and 51.7% were male. Compared with patients with NCS, the prevalence of NCW LAA morphology was higher in patients with CE stroke (58.7% versus 46.3%, P = .1) and ESUS (58.8% versus 46.3%, P = .2), but this difference did not achieve statistical significance.

CONCLUSION

The prevalence of NCW LAA morphology may be similar in patients with ESUS and CE, and may be higher than that in those with NCS. Larger studies are needed to confirm these associations.

Rivaroxaban for secondary stroke prevention in patients with embolic strokes of undetermined source: Design of the NAVIGATE ESUS randomized trial

BACKGROUND

Embolic strokes of undetermined source comprise up to 20% of ischemic strokes. The stroke recurrence rate is substantial with aspirin, widely used for secondary prevention. The New Approach riVaroxaban Inhibition of Factor Xa in a Global trial versus ASA to prevenT Embolism in Embolic Stroke of Undetermined Source international trial will compare the efficacy and safety of rivaroxaban, an oral factor Xa inhibitor, versus aspirin for secondary prevention in patients with recent embolic strokes of undetermined source.

MAIN HYPOTHESIS

In patients with recent embolic strokes of undetermined source, rivaroxaban 15 mg once daily will reduce the risk of recurrent stroke (both ischemic and hemorrhagic) and systemic embolism (primary efficacy outcome) compared with aspirin 100 mg once daily.

DESIGN

Double-blind, randomized trial in patients with embolic strokes of undetermined source, defined as nonlacunar cryptogenic ischemic stroke, enrolled between seven days and six months from the qualifying stroke. The planned sample size of 7000 participants will be recruited from approximately 480 sites in 31 countries between 2014 and 2017 and followed for a mean of about two years until at least 450 primary efficacy outcome events have occurred. The primary safety outcome is major bleeding. Two substudies assess (1) the relative effect of treatments on MRI-determined covert brain infarcts and (2) the biological underpinnings of embolic strokes of undetermined source using genomic and biomarker approaches.

SUMMARY

The New Approach riVaroxaban Inhibition of Factor Xa in a Global trial versus ASA to prevenT Embolism in Embolic Stroke of Undetermined Source trial is evaluating the benefits and risks of rivaroxaban for secondary stroke prevention in embolic strokes of undetermined source patients. Main results are anticipated in 2018.

Recurrent Embolic Strokes of Undetermined Source in a Patient with Extreme Lipoprotein(a) Levels

Lipoprotein(a) is a plasma lipoprotein and known cardiovascular risk factor, most recently implicated in the development of high-risk carotid atherosclerotic plaques without significant carotid stenosis. We present a case of a young African-American female with recurrent embolic strokes of undetermined source. After our thorough investigation, we identified the link between a small, irregular plaque in the right internal carotid artery, and an extremely elevated plasma level of lipoprotein(a) as the source of her embolic strokes.

Identification of Covert Atrial Fibrillation in Cryptogenic Ischemic Stroke: Current Clinical Practice in Japan

BACKGROUND AND AIM

A new insertable cardiac monitor, Reveal LINQ (Medtronic, Dublin, Ireland), was approved for clinical use in Japan in March 2016 for detecting atrial fibrillation in patients who develop ischemic stroke with no clearly definable etiology even after extensive workup, so-called cryptogenic ischemic stroke. Cooperation between a specialist of the Japan Stroke Society and a trained cardiologist or cardiac surgeon is needed both for appropriate patient selection and appropriate management of the device. In this paper, the clinical significance of and diagnostic methods for cryptogenic stroke and covert atrial fibrillation are explained, along with our proposal for the clinical indications for this new device.

METHODS, RESULTS, AND CONCLUSION

The majority of cryptogenic ischemic strokes are considered to be embolic. In particular, covert atrial fibrillation is drawing attention as the causal emboligenic disease, and it was identified in 30% of patients with long-term observation using an insertable cardiac monitor. Should atrial fibrillation be present, there is a high risk of recurrent stroke, and the cardioembolic stroke that appears is generally severe. The ability to identify atrial fibrillation would be beneficial for preventing stroke recurrence, as anticoagulants can then be used as an established method of secondary prevention. Because the use of insertable cardiac monitors is somewhat invasive, and long-term care systems are also needed, patients suitable for examination using the new device would need to be identified on the basis of detailed diagnostics in accordance withcurrent medical practice in Japan.

Embolic Strokes of Unknown Source and Cryptogenic Stroke: Implications in Clinical Practice

Up to a third of strokes are rendered cryptogenic or of undetermined etiology. This number is specifically higher in younger patients. At times, inadequate diagnostic workups, multiple causes, or an under-recognized etiology contributes to this statistic. Embolic stroke of undetermined source, a new clinical entity particularly refers to patients with embolic stroke for whom the etiology of embolism remains unidentified despite through investigations ruling out established cardiac and vascular sources. In this article, we review current classification and discuss important clinical considerations in these patients; highlighting cardiac arrhythmias and structural abnormalities, patent foramen ovale, paradoxical sources, and potentially under-recognized, vascular, inflammatory, autoimmune, and hematologic sources in relation to clinical practice.

Cryptogenic stroke

In about a quarter of ischaemic strokes the cause is undetermined, because the investigation is incomplete or delayed, because there are multiple causes or because the stroke is truly cryptogenic. Cryptogenic stroke can be further classified as non-embolic or embolic. Embolic stroke of undetermined source can be due to paroxysmal atrial fibrillation, minor emboligenic cardiac conditions, atheroembolism, cancer associated and paradoxical embolism through a patent foramen ovale (PFO) or less often a pulmonary fistula. Currently, risk factor control, statins and antiplatelets are the main therapeutic measures to prevent recurrent stroke. There is no evidence to implement routine closure of PFO in patients with cryptogenic stroke. Direct anticoagulants are being evaluated in randomized controlled trials including embolic stroke of undetermined source patients. Advances in high resolution ultrasound or magnetic resonance imaging of extracranial and intracranial vessels and of the heart and prolonged heart rhythm monitoring will be instrumental techniques to identify arterial and cardiac hidden causes of stroke.