Differences between Atrial Fibrillation Detected before and after Stroke and TIA: A Systematic Review and Meta-Analysis

Differences between atrial fibrillation diagnosed before and after stroke: A large real-world cohort study

The clinical characteristics and long-term outcomes of patients with ischemic stroke (IS) and atrial fibrillation detected after stroke (AFDAS) have not been clearly established. Previous studies evaluating patients with AFDAS were limited by the low prescription rates of anticoagulants and short follow-up periods. Consecutive patients hospitalized for IS between 2014 and 2017 were identified from a National Health Insurance Research Database. The included patients were categorized into three groups: (1) known diagnosis of AF (KAF) before the index stroke, (2) AFDAS, and (3) without AF (non-AF). Univariable and multivariable Cox regression analyses were performed to estimate the hazard ratio (HR) for independent variables and recurrent IS, hemorrhagic stroke, or all-cause mortality. We identified 158,909 patients with IS of whom 16,699 (10.5%) had KAF and 7,826 (4.9%) had AFDAS. The patients with AFDAS were younger, more often male, and had lower CHA2DS2-VASc scores (3.8 ± 1.9 versus 4.9 ± 1.8, p < 0.001) than the patients with KAF. Anticoagulant treatment significantly reduced the risks of all outcomes. The standardized mortality rates were 40.4, 28.6, and 18.4 (per 100 person-years) for the patients with KAF, AFDAS, and non-AF, respectively. Compared with AFDAS, KAF was associated with lower risks of recurrent IS [hazard ratio (HR): 0.91, 95% confidence interval (CI): 0.86-0.97, p < 0.01] and hemorrhagic stroke (HR: 0.88, 95% CI: 0.79-0.99, p < 0.01) and a higher risk of all-cause mortality (HR: 1.11, 95% CI: 1.07-1.16, p < 0.001). The risks of recurrent IS and hemorrhagic stroke were higher and of all-cause mortality was lower for patients with AFDAS than with KAF. There is a strong need to refine treatment modalities to reduce the high mortality in patients with KAF and AFDAS.

Impact of prior oral anticoagulation on admission stroke severity in patients with atrial fibrillation

BACKGROUND AND AIMS

In patients with atrial fibrillation, oral anticoagulation therapy is indicated for both primary and secondary prevention of stroke/systemic embolism. Though direct oral anticoagulants with greater safety and efficacy than warfarin were introduced into clinical practice at the beginning of the last decade, even now not all patients with AF have adequate preventative anticoagulant treatment. The primary goal of this study was to evaluate the impact of prior use of oral anticoagulants on admission stroke severity in those with AF. Other aims were, inter alia, to assess the trend in atrial fibrillation prevalence in the years of the HISTORY trials 2012-2021 carried out in the Czech Republic and use of oral anticoagulants (OAC) in ischemic stroke (IS) patients.

METHODS

We analyzed consecutive ischemic stroke patients who had been enrolled in the HISTORY (Heart and Ischemic STrOke Relationship studY) study registered on ClinicalTrials.gov (identifier NCT01541163) in the year 2012 and carried out a yearly comparison (detailed in the text).

RESULTS

In total, there were 1059 patients (55.9% males, mean age 71.7±12.8). There was no significant difference over the time period in rate of known (18.3 vs. 16.5%, P=0.442) or newly detected AF (17.0 vs. 16.0%, P=0.665), but sigificantly more patients with known AF were treated with oral anticoagulants before IS in the year 2021 (32.1 vs. 70.7%, P<0.0001), and direct oral anticoagulants (3.6 vs. 35.4%, P<0.0001). The number of patients with atrial fibrillation had not changed significantly over the years (26.2 vs. 31.3%). Patients on OAC had a lower median admission score on the National Institutes of Health Stroke Scale (NIHSS) than those not using an oral anticoagulant (6 vs. 16, P=0.0004) in 2021.

CONCLUSIONS

There was no significant upward trend in atrial fibrillation in stroke patients admitted between 2012 and 2021, but patients with known AF were significantly more frequently treated with oral anticoagulants and direct oral anticoagulants (DOAC) in 2021. Patients on OAC had lower admission NIHSS scores than those not using any anticoagulent in the year 2021. The difference in the median admission NIHSS between the patients on OAC and those without OAC treatment was not significant in the year 2012 (6 vs. 12, P=0.066). This might be related to the fact that substantially fewer patients in 2012 were on DOACs, which are considered more effective than warfarin.

Patterns of atrial fibrillation, relevant cardiac structural and functional changes predict functional and cognitive outcomes in patients with ischemic stroke and atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) pattern, relevant cardiac changes are important predictors of outcomes in AF, but their impact on patients with ischemic stroke and AF remained unclear. We aimed to explore the impact of AF patterns, cardiac structural and functional markers on long-term functional and cognitive outcomes in ischemic stroke patients with AF.

METHODS

Ischemic stroke patients diagnosed with AF were enrolled in this retrospective cohort study. AF pattern was defined by both traditional and novel classification, in which patients were divided into AF diagnosed after stroke (AFDAS) and known before stroke (KAF). Left atrial (LA) diameter, left ventricular ejection fraction (LVEF), natriuretic peptide (BNP) and cardiac troponin (cTnI) were dichotomized according to the median value. Outcomes include poor functional outcome and cognitive impairment at the 1-year follow-up. Multivariable logistic regression was performed to validate the association between AF pattern, parameters of cardiac change and functional and cognitive outcome.

RESULTS

A total of 377 patients were included. Non-paroxysmal AF patients had a higher risk of poor functional outcome (OR = 3.59, P < 0.0001) and cognitive impairment (OR = 2.38, P = 0.019) than paroxysmal AF patients, while there were no differences between AFDAS and KAF. Lower LVEF (OR = 1.83, P = 0.045) and higher BNP (OR = 2.66, P = 0.001) were associated with poor functional outcome. Lower LVEF (OR = 2.86, P = 0.004), higher LA diameter (OR = 2.72, P = 0.008) and BNP (OR = 2.31, P = 0.023) were associated with cognitive impairment.

CONCLUSIONS

AF type and related cardiac markers can serve as predictors for poor functional and cognitive outcomes. Comprehensive cardiac assessment and monitoring should be strengthened after stroke.

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.

Extended Computed Tomography Angiography for the Successful Diagnosis of Cardioaortic Thrombus in Acute Ischemic Stroke and TIA: Study Protocol for a Randomized Controlled Trial

INTRODUCTION

Cardiac imaging is one of the main components of the etiological investigation of ischemic strokes. However, basic and advanced cardiac imaging remain underused in most stroke centers globally. Computed tomography angiography (CTA) of the supra-aortic and intracranial arteries is the most frequent imaging modality applied during the evaluation of patients with acute ischemic stroke to identify the presence of a large vessel occlusion. Recent evidence from retrospective observational studies has shown a high detection of cardiac thrombi, ranging from 6.6 to 17.4%, by extending a CTA a few cm below the carina to capture cardiac images. However, this approach has never been prospectively compared against usual care in a randomized controlled trial. The Extended Computed Tomography Angiography for the Successful Screening of Cardioaortic Thrombus in Acute Ischemic Stroke and TIA (DAYLIGHT) prospective, randomized, controlled trial evaluates whether an extended CTA (eCTA) + standard-of-care stroke workup results in higher detection rates of cardiac and aortic source of embolism compared to standard-of-care CTA (sCTA) + standard-of-care stroke workup.

METHODS

DAYLIGHT is a single-center, prospective, randomized, open-blinded endpoint trial, aiming to recruit 830 patients with suspected acute ischemic stroke or transient ischemic attack (TIA) being assessed under acute code stroke at the emergency department or at a dedicated urgent stroke prevention clinic. Patients are randomized 1:1 to eCTA versus sCTA. The eCTA expands image acquisition caudally, 6 cm below the carina. All patients receive standard-of-care cardiac imaging and diagnostic stroke workup. The primary efficacy endpoint is the diagnosis of a cardioaortic thrombus after at least 30 days of follow-up. The primary safety endpoint is door-to-CTA completion time. The diagnosis of a qualifying ischemic stroke or TIA is independently adjudicated by a stroke neurologist, blinded to the study arm allocation. Patients without an adjudicated ischemic stroke or TIA are excluded from the analysis. The primary outcome events are adjudicated by a board-certified radiologist with subspecialty training in cardiothoracic radiology and a cardiologist with formal training in cardiac imaging. The primary analysis is performed according to the modified intention-to-diagnose principle and without adjustment by logistic regression models. Results are presented with odds ratios and 95% confidence intervals.

CONCLUSION

The DAYLIGHT trial will provide evidence on whether extending a CTA to include the heart results in an increased detection of cardioaortic thrombi compared to standard-of-care stroke workup.

Effectiveness, utilisation and cost associated with implantable loop recorders versus external monitors after ischaemic or cryptogenic stroke

OBJECTIVE

Implantable loop recorders (ILRs) are increasingly used for long-term rhythm monitoring after ischaemic and cryptogenic stroke, with the goal of detecting atrial fibrillation (AF) and subsequent initiation of oral anticoagulation to reduce risk of adverse clinical outcomes. There is a need to determine the effectiveness of different rhythm monitoring strategies in this context.

METHODS

We conducted a retrospective cohort analysis of individuals with commercial and Medicare Advantage insurance in Optum Labs Data Warehouse who had incident ischaemic or cryptogenic stroke and no prior cardiovascular implantable electronic device from 1 January 2016 to 30 June 2021. Patients were stratified by rhythm monitoring strategy: ILR, long-term continuous external cardiac monitor (>48 hours to 30 days) or Holter monitor (≤48 hours). The primary outcome was risk-adjusted all-cause mortality at 12 months. Secondary outcomes included new diagnosis of AF and oral anticoagulation, bleeding, and costs.

RESULTS

Among 48 901 patients with ischaemic or cryptogenic stroke, 9235 received an ILR, 29 103 long-term continuous external monitor and 10 563 Holter monitor only. Mean age was 69.9 (SD 11.9) years and 53.5% were female. During the 12-month follow-up period, patients who received ILRs compared with those who received long-term continuous external monitors had a higher odds of new diagnosis of AF and oral anticoagulant initiation (adjusted OR 2.27, 95% CI 2.09 to 2.48). Compared with patients who received long-term continuous external monitors, those who received ILRs had similar 12-month mortality (HR 1.00; 95% CI 0.89 to 1.12), with approximately $13 000 higher costs at baseline (including monitor cost) and $2500 higher costs during 12-month follow-up.

CONCLUSIONS

In this large real-world study of patients with ischaemic or cryptogenic stroke, ILR placement resulted in more diagnosis of AF and initiation of oral anticoagulation, but no difference in mortality compared with long-term continuous external monitors.

Prevalence and Characteristics of Known versus Newly Detected Atrial Fibrillation in Ischemic Stroke: A Population-Based Study

BACKGROUND

Atrial fibrillation (AF) is frequently diagnosed during the acute stage of ischemic stroke (IS), and it may reflect undiagnosed AF before stroke, thus representing a missed opportunity for stroke prevention. This population-based study aimed to assess the prevalence of known AF (KAF) and AF diagnosed early after IS (AFDAS) and to compare clinical and brain/arterial imaging characteristics between patients.

METHODS

Among patients with acute IS recorded in the population-based Dijon Stroke Registry, France (2013-2020), we identified those with KAF or AFDAS. AFDAS was considered when AF was diagnosed during the initial work-up based on electrocardiograms, in-hospital continuous electrocardiographic and/or Holter monitoring. Clinical and imaging characteristics on brain CT scan or angio-CT scan when available including old parenchymal lesions, arterial territory of the index IS, and aortic arch, cervical and intracranial arteries atheroma were compared between groups (KAF vs. AFDAS). Regression logistic models were used to assess factors associated with AFDAS (compared to KAF).

RESULTS

Among 1,756 IS patients, 550 (31.3%) had AF (mean age: 83.6 ± 10.3 years old, 60.5% women), of whom 367 (66.7%) presented with KAF and 183 (33.3%) had AFDAS. In multivariable model, hypertension (OR = 0.37; 95% CI: 0.21-0.64, p < 0.001), chronic heart failure (OR = 0.34; 95% CI: 0.18-0.67, p = 0.002), previous stroke (OR = 0.42; 95% CI: 0.26-0.67, p < 0.001), and preexisting dementia (OR = 0.36; 95% CI: 0.21-0.63, p < 0.001) were inversely associated with AFDAS, whereas NIHSS score was associated with AFDAS (OR = 1.02; 95% CI: 1.00-1.05, p = 0.012).

CONCLUSIONS

Our findings indicate a more advanced stage of the atrial cardiomyopathy in KAF as compared with AFDAS patients and may thus contribute to the fact that in these latter patients AF had not been diagnosed prior to stroke. This group of patients undeniably represents a missed opportunity for stroke prevention.

Prevalence, risk factors and prognostic value of atrial fibrillation detected after stroke after haemorrhagic versus ischaemic stroke

BACKGROUND AND OBJECTIVES

Prior evidence suggests that atrial fibrillation detected after stroke (AFDAS) is distinct from known atrial fibrillation (KAF), with particular clinical characteristics and impacts on outcomes in ischaemic stroke. However, the results remained inconsistent in ischaemic stroke, and the role of AFDAS in haemorrhagic stroke remains unclear. Therefore, we aimed to estimate the prevalence, risk factors and prognostic value of AFDAS in haemorrhagic stroke in comparison with ischaemic stroke.

METHODS

This was a multicentre cohort study. Patients who had an ischaemic and haemorrhagic stroke hospitalised in the Chinese Stroke Center Alliance hospitals were enrolled and classified as AFDAS, KAF or sinus rhythm (SR) based on heart rhythm. Univariate and multivariate logistic regression analyses were used to assess the prevalence, characteristics, risk factors and outcomes of AFDAS, KAF and SR in different stroke subtypes.

RESULTS

A total of 913 163 patients, including 818 799 with ischaemic stroke, 83 450 with intracerebral haemorrhage (ICH) and 10 914 with subarachnoid haemorrhage (SAH), were enrolled. AFDAS was the most common in ischaemic stroke. There were differences in the risk factor profile between stroke subtypes; older age is a common independent risk factor shared by ischaemic stroke (OR 1.06, 95% CI 1.06 to 1.06), ICH (OR 1.08, 95% CI 1.07 to 1.09) and SAH (OR 1.07, 95% CI 1.05 to 1.10). Similar to KAF, AFDAS was associated with an increased risk of in-hospital mortality compared with SR in both ischaemic stroke (OR 2.23, 95% CI 1.94 to 2.56) and ICH (OR 2.84, 95% CI 1.84 to 4.38).

DISCUSSION

There are differences in the prevalence, characteristics and risk factors for AFDAS and KAF in different stroke subtypes. AFDAS was associated with an increased risk of mortality compared with SR in both ischaemic stroke and ICH. Rhythm monitoring and risk factor modification after both ischaemic and haemorrhagic stroke are essential in clinical practice. More emphasis and appropriate treatment should be given to AFDAS.

Association of the Timing of Atrial Fibrillation Detection and Insular Involvement With the Risk of Embolic Events After Acute Ischemic Stroke

OBJECTIVE

Atrial fibrillation (AF) detected after insular stroke might arise from autonomic and inflammatory mechanisms triggered by insular damage, and be associated with a low embolic risk. We assessed the association of the timing of AF detection and insular involvement with the risk of embolic events after acute ischemic stroke.

METHODS

Acute ischemic stroke patients with AF who underwent brain magnetic resonance imaging at baseline were enrolled. Patients were classified according to the timing of AF detection (AF detected after stroke [AFDAS] or known AF [KAF]) and insular involvement. The primary outcome was embolic events defined as recurrent ischemic stroke, transient ischemic attack, and systemic embolism within 90 days.

RESULTS

Of 1,548 patients, 360 had AFDAS with insular cortex lesions (+I), 409 had AFDAS without insular cortex lesions (-I), 349 had KAF+I, and 430 had KAF-I. Cumulative incidence rates of embolic events at 90 days in patients with AFDAS+I, AFDAS-I, KAF+I, and KAF-I were 0.8%, 3.5%, 4.9%, and 3.3%, respectively. Patients with AFDAS-I (adjusted hazard ratio 5.04, 95% confidence interval 1.43-17.75), KAF+I (6.18, 1.78-21.46), and KAF-I (5.26, 1.48-18.69) had a significantly higher risk of embolic events than those with AFDAS+I.

INTERPRETATION

Acute ischemic stroke patients with AFDAS and insular cortex lesions had a lower risk of embolic events than those who had AFDAS without insular cortex lesions or those with KAF, regardless of insular involvement. ANN NEUROL 2024;95:338-346.

Atrial Fibrillation Detection and Load: Knowledge Gaps Related to Stroke Prevention

Atrial fibrillation is a major cause of ischemic stroke. Technological advances now support prolonged cardiac rhythm monitoring using either surface electrodes or insertable cardiac monitors. Four major randomized controlled trials show that prolonged cardiac monitoring detects subclinical paroxysmal atrial fibrillation in 9% to 16% of patients with ischemic stroke, including in patients with potential alternative causes such as large artery disease or small vessel occlusion; however, the optimal monitoring strategy, including the target patient population and the monitoring device (whether to use an event monitor, insertable cardiac monitor, or stepped approach) has not been well defined. Furthermore, the clinical significance of very short duration paroxysmal atrial fibrillation remains controversial. The relevance of the duration of monitoring, burden of device-detected atrial fibrillation, and its proximity to the acute ischemic stroke will require more research to define the most effective methods for stroke prevention in this patient population.

Towards a new classification of atrial fibrillation detected after a stroke or a transient ischaemic attack

Globally, up to 1·5 million individuals with ischaemic stroke or transient ischaemic attack can be newly diagnosed with atrial fibrillation per year. In the past decade, evidence has accumulated supporting the notion that atrial fibrillation first detected after a stroke or transient ischaemic attack differs from atrial fibrillation known before the occurrence of as stroke. Atrial fibrillation detected after stroke is associated with a lower prevalence of risk factors, cardiovascular comorbidities, and atrial cardiomyopathy than atrial fibrillation known before stroke occurrence. These differences might explain why it is associated with a lower risk of recurrence of ischaemic stroke than known atrial fibrillation. Patients with ischaemic stroke or transient ischaemic attack can be classified in three categories: no atrial fibrillation, known atrial fibrillation before stroke occurrence, and atrial fibrillation detected after stroke. This classification could harmonise future research in the field and help to understand the role of prolonged cardiac monitoring for secondary stroke prevention with application of a personalised risk-based approach to the selection of patients for anticoagulation.

Diagnosis and Management of Atrial Fibrillation in Acute Ischemic Stroke in the Setting of Reperfusion Therapy: Insights and Strategies for Optimized Care

Reperfusion therapy in the form of intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT) has revolutionised the field of stroke medicine. Atrial fibrillation (AF) patients constitute a major portion of the overall stroke population; however, the prevalence of AF amongst acute ischemic stroke (AIS) patients receiving reperfusion therapy remains unclear. Limitations in our understanding of prevalence in this group of patients are exacerbated by difficulties in appropriately diagnosing AF. Additionally, the benefits of reperfusion therapy are not consistent across all subgroups of AIS patients. More specifically, AIS patients with AF often tend to have poor prognoses despite treatment relative to those without AF. This article aims to present an overview of the diagnostic and therapeutic management of AF and how it mediates outcomes following stroke, most specifically in AIS patients treated with reperfusion therapy. We provide unique insights into AF prevalence and outcomes that could allow healthcare professionals to optimise the treatment and prognosis for AIS patients with AF. Specific indications on acute neurovascular management and secondary stroke prevention in AIS patients with AF are also discussed.

Research on atrial fibrillation mechanisms and prediction of therapeutic prospects: focus on the autonomic nervous system upstream pathways

Atrial fibrillation (AF) is the most common clinical arrhythmia disorder. It can easily lead to complications such as thromboembolism, palpitations, dizziness, angina, heart failure, and stroke. The disability and mortality rates associated with AF are extremely high, significantly affecting the quality of life and work of patients. With the deepening of research into the brain-heart connection, the link between AF and stroke has become increasingly evident. AF is now categorized as either Known Atrial Fibrillation (KAF) or Atrial Fibrillation Detected After Stroke (AFDAS), with stroke as the baseline. This article, through a literature review, briefly summarizes the current pathogenesis of KAF and AFDAS, as well as the status of their clinical pharmacological and non-pharmacological treatments. It has been found that the existing treatments for KAF and AFDAS have limited efficacy and are often associated with significant adverse reactions and a risk of recurrence. Moreover, most drugs and treatment methods tend to focus on a single mechanism pathway. For example, drugs targeting ion channels primarily modulate ion channels and have relatively limited impact on other pathways. This limitation underscores the need to break away from the "one disease, one target, one drug/measurement" dogma for the development of innovative treatments, promoting both drug and non-drug therapies and significantly improving the quality of clinical treatment. With the increasing refinement of the overall mechanisms of KAF and AFDAS, a deeper exploration of physiological pathology, and comprehensive research on the brain-heart relationship, it is imperative to shift from long-term symptom management to more precise and optimized treatment methods that are effective for almost all patients. We anticipate that drugs or non-drug therapies targeting the central nervous system and upstream pathways can guide the simultaneous treatment of multiple downstream pathways in AF, thereby becoming a new breakthrough in AF treatment research.

Detection of Atrial Fibrillation after Ischemic Stroke with an Insertable Cardiac Monitor: A Systematic Review and Individual Patient Data Meta-Analysis of Randomized Clinical Trials

INTRODUCTION

We compared the use of insertable cardiac monitor (ICM) versus non-ICM methods of cardiac monitoring in ischemic stroke patients on the detection of atrial fibrillation (AF) and other clinical outcomes. Current guidelines recommend the routine use of 12-lead electrocardiography or Holter monitoring for AF detection after ischemic stroke. Recent randomized controlled trials have investigated the impact of ICM versus non-ICM methods of cardiac monitoring for AF detection in this population. However, precise recommendations for monitoring poststroke AF are lacking, including the optimal timing, duration, and method of electrocardiography monitoring.

METHODS

A systematic search was conducted on Embase and PubMed from database inception until October 27, 2022, to include randomized controlled trials that compared ICM with non-ICM methods of cardiac monitoring for poststroke AF detection. This yielded 3 randomized controlled trials with a combined cohort of 1,233 patients with a recent ischemic stroke. Individual patient data (IPD) were then reconstructed from Kaplan-Meier curves and analyzed using the shared-frailty Cox model. An aggregate data meta-analysis was conducted for 1,233 patients across all 3 studies for outcomes that could not be reconstructed using IPD.

RESULTS

One-stage meta-analysis demonstrated an increase in the hazard ratio (6.00 95% CI: 3.40-10.58; 195 p < 0.001) of AF detection in patients undergoing monitoring via ICM compared to standard care. The cumulative incidence curves of AF events in patients undergoing ICM and non-ICM separated significantly at 24 days. Aggregate data meta-analysis revealed a significant increase in initiation of anticoagulation (RR: 2.76, 95% CI: 1.89-4.02, p < 0.00001) in the ICM group. However, no significant differences in the incidence of recurrent ischemic stroke, transient ischemic attack, or death were found.

CONCLUSIONS

In this meta-analysis, we found that the use of ICM increased the detection rate of poststroke AF and the rate of anticoagulation initiation in ischemic stroke patients. However, this did not translate into a reduced incidence of recurrent ischemic stroke.

Atrial Fibrillation Detected before or after Stroke: Role of Anticoagulation

BACKGROUND

Atrial fibrillation (AF) known before ischemic stroke (KAF) has been postulated to be an independent category with a recurrence risk higher than that of AF detected after stroke (AFDAS). However, it is unknown whether this risk difference is confounded by pre-existing anticoagulation, which is most common in KAF and also indicates a high ischemic stroke recurrence risk.

METHODS

Individual patient data analysis from 5 prospective cohorts of anticoagulated patients following AF-associated ischemic stroke. We compared the primary (ischemic stroke recurrence) and secondary outcome (all-cause death) among patients with AFDAS versus KAF and among anticoagulation-naïve versus previously anticoagulated patients using multivariable Cox, Fine-Gray models, and goodness-of-fit statistics to investigate the relative independent prognostic importance of AF-category and pre-existing anticoagulation.

RESULTS

Of 4,357 patients, 1,889 (43%) had AFDAS and 2,468 (57%) had KAF, while 3,105 (71%) were anticoagulation-naïve before stroke and 1,252 (29%) were previously anticoagulated. During 6,071 patient-years of follow-up, we observed 244 recurrent strokes and 661 deaths. Only pre-existing anticoagulation (but not KAF) was independently associated with a higher hazard for stroke recurrence in both Cox and Fine-Gray models. Models incorporating pre-existing anticoagulation showed better fit than those with AF category; adding AF-category did not result in better model fit. Neither pre-existing anticoagulation nor KAF were independently associated with death.

CONCLUSION

Our findings challenge the notion that KAF and AFDAS are clinically relevant and distinct prognostic entities. Instead of attributing an independently high stroke recurrence risk to KAF, future research should focus on the causes of stroke despite anticoagulation to develop improved preventive treatments. ANN NEUROL 2023;94:43-54.

Embolic Stroke of Undetermined Source: Current Perspectives on Diagnosis, Investigations, and Management

In 2014, Hart et al. introduced the concept of "embolic stroke of undetermined source" (ESUS) to the clinical-research stroke community. The hypothesis underlying the development of the ESUS construct was that this potentially heterogenous group of stroke mechanisms were largely thromboembolic, and would thus benefit from anticoagulation over antiplatelet for secondary prevention. Since then, 2 large clinical trials have shown that, to date, there is not a clear uniform antithrombotic strategy for secondary prevention after ESUS as it was originally broadly defined. However, this work has yielded valuable information about the patient phenotypes that experience ESUS strokes, as well as hypothesis-generating substudies that have given rise to the next generation of secondary prevention trials aimed at more personalized approaches for different suspected mechanisms of embolic stroke. In parallel with the evolution of ESUS, several studies aimed at screening for atrial fibrillation in the secondary stroke prevention population have generated additional questions about the mechanistic relevance of atrial fibrillation detected after stroke, and how this should inform poststroke workup, and secondary prevention strategies. Herein, we provide a synthesis of the current understanding surrounding the patient phenotypes that experience ESUS strokes, and previous, ongoing, and anticipated clinical trials that will guide earlier and later secondary prevention strategies and poststroke cardiac investigations.

Atrial Fibrillation Detected by Implantable Monitor in Embolic Stroke of Undetermined Source: A New Clinical Entity

Background: High incidence of covert paroxysmal atrial fibrillation (CPAF) detected by an implantable cardiac monitor (ICM) is expected in embolic stroke of undetermined source (ESUS) patients. This study aimed to determine the CPAF rate in an ESUS cohort using ICMs and compare stroke characteristics of patients with CPAF to those with known or inpatient-diagnosed AF (KIDAF). Methods: ESUS patients with ICMs were enrolled. ESUS diagnosis was defined as a non-lacunar stroke in the absence of symptomatic atherosclerotic stenosis (≥50%), no major-risk cardioembolic source, and no other specific cause. ESUS characteristics of patients with CPAF were compared to ESUS patients without CPAF and to KIDAF stroke patients. Results: During the median follow-up of 476 (371–615) days, CPAF was newly detected in 38/163 (23.31%) patients within 236 (115.50–510.75) days after the stroke. CPAF was independently associated to older age, coronaropathy, left atrial dilation, and atrial hyperexcitability, but not to stroke severity. Compared to KIDAF strokes, ESUS with CPAF had lower rates of proximal occlusion leading to milder clinical severity (NIHSS: 3.00 (1.00–8.25) vs. 14.50 (6.00–21.00)). Conclusions: Our study revealed a high proportion of CPAF in ESUS. We highlight that CPAF is a distinct clinical entity compared to KIDAF based on differences in stroke characteristics and AF diagnosis temporality.

Stroke-Heart Syndrome: Recent Advances and Challenges

After ischemic stroke, there is a significant burden of cardiovascular complications, both in the acute and chronic phase. Severe adverse cardiac events occur in 10% to 20% of patients within the first few days after stroke and comprise a continuum of cardiac changes ranging from acute myocardial injury and coronary syndromes to heart failure or arrhythmia. Recently, the term stroke–heart syndrome was introduced to provide an integrated conceptual framework that summarizes neurocardiogenic mechanisms that lead to these cardiac events after stroke. New findings from experimental and clinical studies have further refined our understanding of the clinical manifestations, pathophysiology, and potential long‐term consequences of the stroke–heart syndrome. Local cerebral and systemic mediators, which mainly involve autonomic dysfunction and increased inflammation, may lead to altered cardiomyocyte metabolism, dysregulation of (tissue‐resident) leukocyte populations, and (micro‐) vascular changes. However, at the individual patient level, it remains challenging to differentiate between comorbid cardiovascular conditions and stroke‐induced heart injury. Therefore, further research activities led by joint teams of basic and clinical researchers with backgrounds in both cardiology and neurology are needed to identify the most relevant therapeutic targets that can be tested in clinical trials.

Once versus twice daily direct oral anticoagulants in patients with recent stroke and atrial fibrillation

BACKGROUND

Data on the safety and effectiveness of once-daily (QD) versus twice-daily (BID) direct oral anticoagulants (DOAC) in comparison to vitamin K antagonists (VKA) and to one another in patients with atrial fibrillation (AF) and recent stroke are scarce.

PATIENTS AND METHODS

Based on prospectively obtained data from the observational registry Novel-Oral-Anticoagulants-in-Ischemic-Stroke-Patients(NOACISP)-LONGTERM (NCT03826927) from Basel, Switzerland, we compared the occurrence of the primary outcome - the composite of recurrent ischemic stroke, major bleeding, and all-cause death - among consecutive AF patients treated with either VKA, QD DOAC, or BID DOAC following a recent stroke using Cox proportional hazards regression including adjustment for potential confounders.

RESULTS

We analyzed 956 patients (median age 80 years, 46% female), of whom 128 received VKA (13.4%), 264 QD DOAC (27.6%), and 564 BID DOAC (59%). Over a total follow-up of 1596 patient-years, both QD DOAC and BID DOAC showed a lower hazard for the composite outcome compared to VKA (adjusted HR [95% CI] 0.69 [0.48, 1.01] and 0.66 [0.47, 0.91], respectively). Upon direct comparison, the hazard for the composite outcome did not differ between patients treated with QD versus BID DOAC (adjusted HR [95% CI] 0.94 [0.70, 1.26]). Secondary analyses focusing on the individual components of the composite outcome revealed no clear differences in the risk-benefit profile of QD versus BID DOAC.

DISCUSSION AND CONCLUSION

The overall benefit of DOAC over VKA seems to apply to both QD and BID DOAC in AF patients with a recent stroke, without clear evidence that one DOAC dosing regimen is more advantageous than the other.

Oral anticoagulant decreases stroke recurrence in patients with atrial fibrillation detected after stroke

Background

Atrial fibrillation detected after stroke (AFDAS) has a lower risk of ischemic stroke recurrence than known atrial fibrillation (KAF). While the benefit of oral anticoagulants (OAC) for preventing ischemic stroke recurrence in KAF is well established, their role in patients with AFDAS is more controversial. This study aimed to evaluate the association between OAC use and the risk of recurrent ischemic stroke in patients with AFDAS in a real-world setting.

Methods

This nationwide retrospective cohort study was conducted using the Taiwan National Health Insurance Research Database. Patients hospitalized with a first-ever ischemic stroke and AFDAS confirmed within 30 days after hospitalization were assigned to OAC and non-OAC cohorts. Inverse probability of treatment weighting was applied to balance the baseline characteristics of the cohorts. The primary outcome was ischemic stroke recurrence. Secondary outcomes were intracranial hemorrhage (ICH), death, and the composite outcome of "ischemic stroke recurrence, ICH, or death." Multivariate Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR) and 95% confidence intervals (CI).

Results

A total of 4,508 hospitalized patients with stroke and AFDAS were identified. Based on OAC use, 2,856 and 1,652 patients were assigned to the OAC and non-OAC groups, respectively. During the follow-up period (median duration, 2.76 years), the OAC cohort exhibited a lower risk of ischemic stroke recurrence (aHR, 0.84; 95% CI, 0.70-0.99), death (aHR, 0.65; 95% CI, 0.58-0.73), and composite outcome (aHR, 0.70; 95% CI, 0.63-0.78) than did the non-OAC cohort. The risk of ICH (aHR, 0.96; 95% CI, 0.62-1.50) was not significantly different between the two cohorts.

Conclusion

OAC use in patients with AFDAS was associated with reduced risk of ischemic stroke recurrence, without an increased risk of ICH. This supports current guidelines recommending OACs for secondary stroke prevention in patients with AF, regardless of the time of diagnosis.

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

Background

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

Methods

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

Results

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

Conclusion

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

Sex Hormone-Specific Neuroanatomy of Takotsubo Syndrome: Is the Insular Cortex a Moderator?

Takotsubo syndrome (TTS), a transient form of dysfunction in the heart’s left ventricle, occurs predominantly in postmenopausal women who have emotional stress. Earlier studies support the concept that the human circulatory system is modulated by a cortical network (consisting of the anterior cingulate gyrus, amygdala, and insular cortex (Ic)) that plays a pivotal role in the central autonomic nervous system in relation to emotional stressors. The Ic plays a crucial role in the sympathovagal balance, and decreased levels of female sex hormones have been speculated to change functional cerebral asymmetry, with a possible link to autonomic instability. In this review, we focus on the Ic as an important moderator of the human brain–heart axis in association with sex hormones. We also summarize the current knowledge regarding the sex-specific neuroanatomy in TTS.