Prognostic value of trans-thoracic echocardiography in patients with acute stroke and atrial fibrillation: findings from the RAF study

New-onset as opposed to established atrial fibrillation as a risk factor for incident stroke

BACKGROUND

Atrial fibrillation (AF) is an established risk factor for acute ischemic stroke (AIS). It remains unclear if new-onset AF confers a higher risk of AIS than longer-standing AF.

METHODS

We retrospectively analyzed all stroke-free patients who underwent transthoracic echocardiography (TTE) in the Henry Ford Health System between March 6 and September 6, 2016. Incident AIS and new-onset AF were ascertained by the presence of new diagnostic codes in the electronic medical record over a follow-up period of up to 5 years. Cox proportional hazards regression was used to identify risk factors for new-onset AF or AIS.

RESULTS

Of 7310 patients who underwent baseline TTE the mean age was 65 years, 54% were female, 51% were Caucasian, and 46% had left atrial enlargement (LAE). Of at-risk patients, 10.9% developed new-onset AF and 2.9% experienced incident AIS. The risk of new-onset AF among at-risk patients was 3.1 times higher among patients with any degree of LAE compared to those with normal LA size (95% CI 2.6-3.6, P < 0.0001). New-onset AF, more than established AF, in turn had a powerful association with incident AIS. The cumulative 5-year risk of AIS was 3.5% in those without AF, 5.9% in those with established AF prior to TTE, and 20.1% in those with new-onset AF (P < 0.0001). In multivariable analysis new-onset AF had the strongest association with incident AIS (P < 0.0001), followed by increasing age (P = 0.0025), black race (P = 0.0032), and smoking (P = 0.0063).

CONCLUSIONS

New-onset AF has a strong relationship with incident AIS. LAE was present in nearly half of stroke-free patients undergoing TTE, and was associated with a significantly higher likelihood of new-onset AF during follow-up. Vigilant cardiac monitoring for AF in individuals with LAE, coupled with the timely initiation of anticoagulation, may be an important strategy for the primary prevention of AF-related stroke.

Left ventricular hypertrophy and left atrial size are associated with ischemic strokes among non-vitamin K antagonist oral anticoagulant users

BACKGROUND

Ischemic strokes (IS) occurring in patients taking non-vitamin K antagonist oral anticoagulants (NOACs) are becoming increasingly more frequent. We aimed to determine the clinical, echocardiographic, and neuroimaging markers associated with developing IS in patients taking NOACs for atrial fibrillation.

METHODS

From a quaternary care center, clinical/radiologic data were collected from consecutive NOAC users with IS and age-matched controls without IS. Brain MRIs were reviewed for markers of cerebral small vessel disease. Variables with significant differences between groups were entered into a multivariable regression model to determine predictors of IS. Among IS patients, a Cox regression analysis was constructed to determine predictors of IS recurrence during follow-up.

RESULTS

112 patients with IS and 94 controls were included in the study. Variables significantly different between groups included apixaban use, dabigatran use, prior cerebrovascular events, hemoglobin A1c (HbA1c), left ventricular hypertrophy, left atrial volume index, and severe white matter hyperintensities. After multivariable adjustment, prior cerebrovascular events (aOR 23.86, 95% CI [6.02-94.48]), HbA1c levels (aOR 2.36, 95% CI [1.39-3.99]), left ventricular hypertrophy (aOR 2.73, 95% CI [1.11-6.71]) and left atrial volume index (aOR 1.05, 95% CI [1.01-1.08]) increased the risk of stroke, whereas apixaban use appeared to decrease the risk (aOR 0.38, 95% CI [0.16-0.92]). Malignancy was associated with IS recurrence (aHR 4.90, 95% CI [1.35-18.42]) after adjustment for age and chronic renal failure.

CONCLUSIONS

Prior cerebrovascular events, diabetes, left ventricular hypertrophy, and increased left atrial size are risk factors for developing an IS among NOAC users.

Left atrial appendage thrombus in acute stroke: diagnostic accuracy of CT angiography compared to transesophageal echocardiography

OBJECTIVES

To evaluate the value of an extended emergency computed tomography angiography (CTA) including cardiac imaging in patients with acute ischemic stroke for the detection of left atrial appendage (LAA) thrombus compared to transesophageal echocardiography (TEE) as a reference standard.

MATERIALS AND METHODS

We conducted a retrospective case-control study of patients with presumed acute ischemic stroke who had undergone non-ECG-gated CTA for the craniocervical vessels with an extended coverage including the heart in the context of emergency stroke evaluation and for whom TEE was available as part of the routine stroke diagnostic. We selected cases with evidence of LAA thrombus in TEE and controls without LAA thrombus in TEE in a 1:3 ratio. Two independent observers analyzed CTA images for presence of LAA thrombus and were blinded to the presence of thrombus in TEE.

RESULTS

Twenty-two patients with LAA thrombus in TEE, and 66 patients without LAA thrombus in TEE were included. The detection of LAA thrombus using CTA showed a sensitivity of 63.6%, a specificity of 81.8%, a positive predictive value of 53.9% and a negative predicted value of 87.1%. Interobserver agreement was only moderate (Cohen´s κ = 0.43).

CONCLUSIONS

An extended emergency CTA including cardiac imaging can be helpful in early risk stratification in patients with stroke of cardioembolic origin. However, our data show that a standard CTA of craniocervical vessels with extended coverage of the heart is of limited value when compared to TEE, the standard method of detecting LAA thrombi.

Antithrombotic dilemmas in stroke medicine: new data, unsolved challenges

Antithrombotic therapy is a key element of secondary prevention in patients who have had an ischaemic stroke or transient ischaemic attack. However, its use in clinical practice is not always straightforward. This review provides an update on certain difficult scenarios in antithrombotic management, with a focus on recent clinical trials and large observational studies. We discuss the approach to patients with an indication for antithrombotic treatment who also have clinical or radiological evidence of previous intracranial bleeding, patients with indications for both anticoagulant and antiplatelet treatment, and patients in whom antithrombotic treatment fails to prevent stroke. We also review the timing of anticoagulation initiation after cardioembolic stroke, and the use of antithrombotics in patients with asymptomatic cerebrovascular disease. Despite a wealth of new evidence, numerous uncertainties remain and we highlight ongoing trials addressing these.

Yield of Echocardiography in Ischemic Stroke and Patients With Transient Ischemic Attack With Established Indications for Long-Term Direct Oral Anticoagulant Therapy: A Cross-Sectional Diagnostic Cohort Study

Background

We aimed to determine the diagnostic yield of transthoracic (TTE) and transesophageal echocardiography (TEE) in patients with ischemic stroke and transient ischemic attack with established indications for direct oral anticoagulants before the index event.

Methods and Results

This was a retrospective cohort study of consecutive patients with preceding established indications for long‐term therapeutic direct oral anticoagulants presenting to a single comprehensive stroke center with ischemic stroke or transient ischemic attack. Choice of echocardiography modality was based on expert recommendations. The primary outcome was a composite of prespecified management‐relevant high‐risk findings adjudicated by an expert panel, based on TTE and TEE reports according to evidence‐based recommendations. Explorative analyses were performed to identify biomarkers associated with the primary outcome. Of 424 patients included (median [interquartile range] age, 78 [70–84] years; 175 [41%] women; National Institutes of Health Stroke Scale, 4 [1–12]; 67% atrial fibrillation), 292 (69%) underwent echocardiography, while 132 (31%) did not. Modality was TTE in 191 (45%) and TEE in 101 (24%). Median time from index event to echocardiography was 2 (1–3) days. TTE identified 26 of 191 (14%) patients with 35 management‐relevant pathologies. TEE identified 16 of 101(16%) patients with 20 management‐relevant pathologies. Most management‐relevant findings represented indicated coronary artery disease and valvular pathologies. In a further 3 of 191 (2%) patients with TTE and 4 of 101 (4%) patients with TEE, other relevant findings were identified. Variables associated with management‐relevant high‐risk pathologies included more severe stroke, diabetes, and laboratory biomarkers (NT‐proBNP [N‐terminal pro‐B‐type natriuretic peptide], C‐reactive protein, d‐dimer, and troponin levels).

Conclusions

In patients with established indications for long‐term direct oral anticoagulant therapy and stroke who received echocardiography, both TTE and TEE identified a relevant and similar proportion of management‐relevant high‐risk pathologies and predictive biomarkers could help to guide diagnostic workup in such patients.

Undertreatment of Anticoagulant Therapy in Hospitalized Acute Ischemic Stroke Patients With Atrial Fibrillation

Background

This study aimed to investigate the prevalence and factors associated with the initiation of oral anticoagulation among patients with acute ischemic stroke (AIS) and concurrent atrial fibrillation (AF) at discharge in China.

Methods

We continuously included hospitalized patients with AIS with an AF diagnosis registered in the computer-based Online Database of Acute Stroke Patients for Stroke Management Quality Evaluation (CASE II) from January 2016 to December 2020 and divided them into a and non-anticoagulant groups according to the medications at discharge. Binary logistic regression was used to determine the factors associated with the prescription of anticoagulants in patients with AF.

Results

A total of 16,162 patients were enrolled. The mean age was 77 ± 9 years, 8,596 (53.2%) were males, and the median baseline National Institute of Health Stroke Scale score was 5 (2–12). Of the 14,838 patients without contraindications of antithrombotic therapy, 6,335 (42.7%) patients were initiated with anticoagulation treatment at discharge. Prior history of hemorrhagic stroke (OR 0.647, p < 0.001) and gastrointestinal bleeding (OR 0.607, p = 0.003) were associated with a lower rate of anticoagulation at discharge. Patients with any intracranial hemorrhage (OR 0.268, p < 0.001), gastrointestinal bleeding (OR 0.353, p < 0.001), or pneumonia during hospitalization (OR 0.601, p < 0.001) were less likely to receive anticoagulants at discharge. Among 7,807 patients with previously diagnosed AF and high risk of stroke (CHA₂DS₂-VASc ≥2), only 1,585 (20.3%) had been receiving anticoagulation treatment prior to the onset of stroke. However, the mean international normalized ratio (INR) was 1.5 on the first test during hospitalization in patients receiving warfarin. Patients complicated with a previous history of ischemic stroke/transient ischemic attack (TIA; OR 2.303, p < 0.001) and peripheral artery disease (OR 1.456, p = 0.003) were more common to start anticoagulants.

Conclusions

Less than half of patients with AIS and concurrent AF initiated guideline-recommended oral anticoagulation at discharge, while only 20% of patients with previously diagnosed AF with a high risk of stroke had been using anticoagulants prior to the onset of stroke, which highlights a large care gap in hospitalized stroke patients and the importance of AF management.

Difficult issues in the management of patients with atrial fibrillation: a neurologist's point of view

The article evaluates recent perspectives about the role of oral anticoagulants in the secondary prevention of cardioembolic stroke. The timing of prescribing drugs for ischemic stroke and transient ischemic attack is discussed in accordance with current clinical guidelines and the results of clinical trials. The issues of prescribing oral anticoagulants in some problematic situations, such as the elderly and senile age, reperfusion therapy, presence of hemorrhagic transformation, combined atherosclerosis of major head and neck arteries, cerebral microangiopathy, history of intracerebral hemorrhage, cryptogenic stroke, and low patient compliance are considered. Finally, an anticoagulant therapy algorithm in the acute period of cardioembolic stroke is presented.

A Review of Biomarkers for Ischemic Stroke Evaluation in Patients With Non-valvular Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide and results in a significantly increased ischemic stroke (IS) risk. IS risk stratification tools are widely being applied to guide anticoagulation treatment decisions and duration in patients with non-valvular AF (NVAF). The CHA₂DS₂-VASc score is largely validated and currently recommended by renowned guidelines. However, this score is heavily dependent on age, sex, and comorbidities, and exhibits only moderate predictive power. Finding effective and validated clinical biomarkers to assist in personalized IS risk evaluation has become one of the promising directions in the prevention and treatment of NVAF. A number of studies in recent years have explored differentially expressed biomarkers in NVAF patients with and without IS, and the potential role of various biomarkers for prediction or early diagnosis of IS in patients with NVAF. In this review, we describe the clinical application and utility of AF characteristics, cardiac imaging and electrocardiogram markers, arterial stiffness and atherosclerosis-related markers, circulating biomarkers, and novel genetic markers in IS diagnosis and management of patients with NVAF. We conclude that at present, there is no consensus understanding of a desirable biomarker for IS risk stratification in NVAF, and enrolling these biomarkers into extant models also remains challenging. Further prospective cohorts and trials are needed to integrate various clinical risk factors and biomarkers to optimize IS prediction in patients with NVAF. However, we believe that the growing insight into molecular mechanisms and in-depth understanding of existing and emerging biomarkers may further improve the IS risk identification and guide anticoagulation therapy in patients with NVAF.

Left atrial size and risk of recurrent ischemic stroke in cardiogenic cerebral embolism

BACKGROUND

Left atrial enlargement (LAE) was reported to be associated with ischemic stroke and its recurrence. Limited data are available on the relationship of LAE and cardiogenic cerebral embolism (CCE). Our aim is to access the association of left atrial size and the recurrence of ischemic stroke in CCE.

METHODS

We prospectively included 303 CCE patients who underwent transthoracic echocardiography (TTE). Left atrial size was estimated with left atrial diameter (LAD), diameter/height (LAD/H), and left atrial diameter/body surface area (LAD/BSA). The endpoint was one-year recurrent ischemic stroke. Cox proportional hazard models were performed to access the association between left atrial size and recurrent ischemic stroke.

RESULTS

During follow-up, 27 patients suffered recurrent ischemic stroke. In multivariate COX regression models adjusted for confounders including age, gender, hypertension, diabetes, and history of stroke or transient ischemic attack (TIA), platelet count, fasting blood glucose (FBG), antithrombotic drugs at discharge, stroke volume, and cardiac output, LAD, LAD/H, and LAD/BSA all were independent risk factors of recurrent ischemic stroke [LAD: HR 1.065, 95% CI (1.006-1.128), p = .029; LAD/H: HR 1.157, 95% CI (1.066-1.255), p < .001; LAD/BSA: HR 1.128, 95% CI (1.059-1.202), p < .001]. Receiver-operator characteristic curves showed that LAD/BSA had better predicting effect. The area under the curve (AUC) was 0.543 [95%CI (0.444-0.642), p = .461) for LAD, 0.626 [95%CI (0.530-0.723), p = .03] for LAD/H, and 0.655 [95%CI (0.558-0.752), p = .008] for LAD/BSA.

CONCLUSION

LAE is an independent risk factor for one-year recurrence of ischemic stroke in patients with CCE.

Can echocardiography improve the prediction of thromboembolic risk in atrial fibrillation? Evidences and perspectives

Atrial fibrillation is the most common arrhythmia and its prevalence is expected to further increase. Patients with atrial fibrillation have an increased risk of stroke (fivefold increased risk), heart failure, and death. In patients with non-valvular atrial fibrillation, the most recent guidelines recommend the use of the CHA₂DS₂-VASc (congestive heart failure, arterial hypertension, age > 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category) scoring system to identify those who may benefit from oral anticoagulant treatment. Guidelines recommend initiation of oral anticoagulation with vitamin K antagonists or direct oral anticoagulants in men with a score ≥ 2 and in women with a score ≥ 3, while oral anticoagulation in individuals with a score of 0 is not recommended. Accordingly, men with CHA₂DS₂VASc score = 1 (and women with CHA₂DS₂VASc = 2) represent a grey zone where guidelines do not provide a definite oral anticoagulant indication. Implementation of risk stratification with transthoracic echocardiography could be extremely useful. Both prospective and observational studies using transthoracic echocardiography prediction of events and studies utilizing transesophageal echocardiographic parameters as surrogate markers of thromboembolic events make sustainable the hypothesis that echocardiography could improve thromboembolism prediction in non-valvular atrial fibrillation. However, because of some controversial results of different studies, determination of the best echocardiographic parameter predicting thromboembolic events in atrial fibrillation remains uncertain. The combination of left atrial enlargement with left atrial function (in particular assessing left atrial strain) appears to be very valuable, but needs to be confirmed in large-scale multi-center trials.

Association of ABCB1 C3435T Polymorphism with Echocardiographic Index Among Patients with Atherosclerotic Ischemic Stroke and Transient Ischemic Attack

Emerging evidence has suggested that patients with ischemic stroke (IS) and/or transient ischemic attack (TIA) are more likely to exhibit myocardial disorders, which can be reflected by transthoracic echocardiography (TTE). ATP binding cassette transporter 1 (ABCB1) plays an important role in the development and progression of atherosclerotic pathology. The objective of the current study was to investigate the associations of ABCB1 C3435T polymorphism with echocardiographic performances among patients with acute ischemic stroke. Patients with IS or TIA, who were hospitalized and received TTE between October 2016 to March 2019, were enrolled in this study. Demographic data and echocardiographic parameters of each participant were recorded. We included 122 patients, with the respective distribution of 12.30%, 48.36%, and 39.34% in CC, CT, and TT genotypes. There were significant differences among the three ABCB1 types, with respect to RV (P = 0.036). The presence of the TT genotype was associated with increased MVE (OR = 0.13, P = 0.02) but correlated with decreased RV (OR = -1.46, P = 0.02). Our study indicated that ABCB1 C3435T polymorphism is associated with echocardiographic parameters among patients with acute ischemic stroke. The presence of the TT genotype is associated with diastolic function and cardiac hypertrophy.

Atrial Fibrillation, Cancer and Echocardiography

Nonvalvular atrial fibrillation (AF) is a relatively frequent arrhythmia in cancer patients; it is possibly due to direct effect of cancer or consequence of cancer therapies. AF creates important problems for both therapeutic management and prognosis in cancer patients. The anticoagulation of cancer patients presenting AF is a main issue because of the difficult balance between thromboembolic and bleeding risks, both elevated in this clinical setting. A comprehensive echo Doppler examination is mandatory to identify the eventual sources of emboli in left atrial (LA) cavity, mainly the transesophageal echocardiography (TEE), but also to predict the subsequent development of heart failure. This evaluation is particularly important to graduate anticoagulation and to prevent and manage symptoms/signs of heart failure. The performance of a TEE precardioversion is highly encouraged to detect possible thrombi in LA appendage. A careful assessment of LA size (LA volume index) and function (LA emptying fraction and/or LA strain) should always be planned to predict the possible recurrence of AF paroxysmal episodes. This is in fact a key action, not only from the cardiologic point of view but also for the oncologic perspectives in individual situations. Patients with larger left atrium and more impaired LA function should be addressed toward a less aggressive cancer treatment, with drugs which are not associated or are poorly related with the risk of AF development. A correct and comprehensive echocardiographic assessment could even induce the oncologist to change the cancer management balancing the oncologic and the cardiac risk.

Timing of Initiation of Oral Anticoagulation after Acute Ischemic Stroke in Patients with Atrial Fibrillation

Patients with atrial fibrillation (AF) who suffer an acute ischemic stroke are at risk for both hemorrhagic transformation and recurrent ischemic stroke in the acute post-stroke period. Oral anticoagulants are recommended for secondary stroke prevention in patients with AF. The optimal time to initiate anticoagulant therapy after acute ischemic stroke in patients with AF is uncertain. There is concern that early initiation increases the risk of hemorrhagic transformation, whereas delayed initiation leaves the patient at risk for recurrent ischemic stroke. In this article, we provide a review of the risk of hemorrhagic transformation of acute ischemic stroke as well as review the literature and major guidelines addressing the timing of anticoagulation initiation after an acute ischemic stroke in patients with AF. Relevant articles published from 1990 to the present were identified using the PubMed and Embase databases. The majority of available literature is observational data. Large ischemic lesions, cerebral microbleeds, thrombolytic therapy, and other clinical factors may increase the risk of hemorrhagic transformation of an acute ischemic stroke. Parenteral anticoagulation within 48 hours is associated with an increased risk of hemorrhagic transformation and is not recommended. Insufficient data exist to support the safety of routine oral anticoagulant (direct oral anticoagulants or warfarin) initiation within 48 hours of an acute ischemic stroke. Direct oral anticoagulant initiation within 2 days of an acute ischemic stroke is associated with a 5% rate of hemorrhagic transformation. Infarct size and presence of hemorrhage are important factors in identifying the optimal time to initiation and should guide decisions when available. A recommended framework for patient decision making is provided. Randomized controlled trials in this area are needed to identify the optimal timing of anticoagulation initiation, and such trials are under way.

Long-Term Outcomes of Real-World Korean Patients with Atrial-Fibrillation-Related Stroke and Severely Decreased Ejection Fraction

BACKGROUND AND PURPOSE

The clinical implications of echocardiography findings for long-term outcomes in atrial fibrillation (AF)-related stroke patients are unknown.

METHODS

This was a substudy of the Korean ATrial fibrillaTion EvaluatioN regisTry in Ischemic strOke patieNts (K-ATTENTION), which is a multicenter-based cohort comprising prospective stroke registries from 11 tertiary centers. Stroke survivors who underwent two-dimensional transthoracic echocardiography during hospitalization were enrolled. Echocardiography markers included the left-ventricle (LV) ejection fraction (LVEF), the left atrium diameter, and the ratio of the peak transmitral filling velocity to the mean mitral annular velocity during early diastole (E/e' ratio). LVEF was categorized into normal (≥55%), mildly decreased (>40% and <55%), and severely decreased (≤40%). The E/e' ratio associated with the LV filling pressure was categorized into normal (<8), borderline (≥8 and <15), and elevated (≥15). Kaplan-Meier and Cox regression analyses were performed for recurrent stroke, major adverse cardiac events, and all-cause death.

RESULTS

This study finally included 1,947 patients. Over a median follow-up of 1.65 years (interquartile range, 0.42-2.87 years), the rates of recurrent stroke, major adverse cardiac events, and all-cause death were 35.1, 10.8, and 69.6 cases per 1,000 person-years, respectively. Multivariable analyses demonstrated that severely decreased LVEF was associated with a higher risks of major adverse cardiac events [hazard ratio (HR), 3.91; 95% confidence interval (CI), 1.58-9.69] and all-cause death (HR, 1.95; 95% CI, 1.23-3.10). The multivariable fractional polynomial plot indicated that recurrent stroke might be associated with a lower LVEF.

CONCLUSIONS

Severe LV systolic dysfunction could be a determinant of long-term outcomes in AF-related stroke.

Cardiac imaging after ischemic stroke : Echocardiography, CT, or MRI?

About 20–25% of all ischemic strokes are of cardioembolic etiology, with atrial fibrillation and heart failure as the most common underlying pathologies. Diagnostic work-up by noninvasive cardiac imaging is essential since it may lead to changes in therapy, e.g., in—but not exclusively—secondary stroke prevention. Echocardiography remains the cornerstone of cardiac imaging after ischemic stroke, with the combination of transthoracic and transesophageal echocardiography as gold standard thanks to their high sensitivity for many common pathologies. Transesophageal echocardiography should be considered as the initial diagnostic tool when a cardioembolic source of stroke is suspected. However, to date, there is no proven benefit of transesophageal echocardiography-related therapy changes on the main outcomes after ischemic stroke. Based on the currently available data, cardiac computed tomography and magnetic resonance imaging should be regarded as complementary methods to echocardiography, providing additional information in specific situations; however, they cannot be recommended as first-line modalities.

Baseline D-Dimer Levels as a Risk Assessment Biomarker for Recurrent Stroke in Patients with Combined Atrial Fibrillation and Atherosclerosis

Background: We investigated the effect of D-dimer levels and efficacy of different antithrombotic therapies according to the baseline D-dimer levels on recurrent stroke in patients with atrial fibrillation (AF)-related stroke and atherosclerosis. Methods: We enrolled 1441 patients with AF-related stroke and atherosclerosis in this nationwide multicenter study. The primary outcome measure was the occurrence of recurrent ischemic stroke over a 3-year period. Results: High D-dimer levels (≥2 μg/mL) were significantly associated with higher risk of recurrent ischemic stroke (adjusted hazard ratio (HR), 1.80; 95% confidence interval (CI), 1.13–2.84; p = 0.012). The risk of recurrent stroke was similar between the anticoagulant and the antiplatelet groups in all subjects (adjusted HR, 0.78; 95% CI, 0.46–1.32; p = 0.369). However, in patients with high D-dimer levels (≥2 μg/mL), risk of recurrent stroke was significantly lower in the anticoagulant group than in the antiplatelet group (adjusted HR, 0.40; 95% CI, 0.18–0.87; p = 0.022). Conclusion: Our findings suggested that baseline D-dimer levels could be used as a risk assessment biomarker of recurrent stroke in patients with AF-related stroke and atherosclerosis. High D-dimer levels would facilitate the identification of patients who are more likely to benefit from anticoagulants to ensure secondary prevention of stroke.

Timing of anticoagulation after recent ischaemic stroke in patients with atrial fibrillation

BACKGROUND

About 13-26% of all acute ischaemic strokes are related to non-valvular atrial fibrillation, the most common cardiac arrhythmia globally. Deciding when to initiate oral anticoagulation in patients with non-valvular atrial fibrillation is a longstanding, common, and unresolved clinical challenge. Although the risk of early recurrent ischaemic stroke is high in this population, early oral anticoagulation is suspected to increase the risk of potentially harmful intracranial haemorrhage, including haemorrhagic transformation of the infarct. This assumption, and current treatment guidelines, are based on historical, mostly observational data from patients with ischaemic stroke and atrial fibrillation treated with heparins, heparinoids, or vitamin K antagonists (VKAs) to prevent recurrent ischaemic stroke. Randomised controlled trials have subsequently shown that direct oral anticoagulants (DOACs; ie, apixaban, dabigatran, edoxaban, and rivaroxaban) are at least as effective as VKAs in primary and secondary prevention of atrial fibrillation-related ischaemic stroke, with around half the risk of intracranial haemorrhage. However, none of these DOAC trials included patients who had experienced ischaemic stroke recently (within the first few weeks). Clinicians therefore remain uncertain regarding when to commence DOAC administration after acute ischaemic stroke in patients with atrial fibrillation.

RECENT DEVELOPMENTS

Prospective observational studies and two small randomised trials have investigated the risks and benefits of early DOAC-administration initiation (most with a median delay of 3-5 days) in mild-to-moderate atrial fibrillation-associated ischaemic stroke. These studies reported that early DOAC treatment was associated with a low frequency of clinically symptomatic intracranial haemorrhage or surrogate haemorrhagic lesions on MRI scans, whereas later DOAC-administration initiation (ie, >7 days or >14 days after index stroke) was associated with an increased frequency of recurrent ischaemic stroke. WHERE NEXT?: Adequately powered randomised controlled trials comparing early to later oral anticoagulation with DOACs in ischaemic stroke associated with atrial fibrillation are justified to confirm the acceptable safety and efficacy of this strategy. Four such randomised controlled trials (collectively planned to include around 9000 participants) are underway, either using single cutoff timepoints for early versus late DOAC-administration initiation, or selecting DOAC-administration timing according to the severity and imaging features of the ischaemic stroke. The results of these trials should help to establish the optimal timing to initiate DOAC administration after recent ischaemic stroke and whether the timing should differ according to stroke severity. Results of these trials are expected from 2021.

Left atrial size and risk of recurrent ischemic stroke in a Chinese population

BACKGROUND

Although a number of studies have reported the role of an increased left atrial (LA) size on stroke, limited data are collected about the relationship between LA enlargement and recurrent ischemic stroke in the Chinese population. Our aim was to assess the association of LA size with the risk of stroke recurrence, particularly with recurrent cardioembolic or cryptogenic stroke in ischemic stroke patients.

METHODS

The study recruited 313 consecutive patients with acute first-ever ischemic stroke. Echocardiographic LA diameter was measured and indexed by height and body surface area separately. The endpoint was recurrent ischemic stroke. Cox proportional hazard models were used to examine the association of LA size with total recurrent ischemic stroke and recurrent cardioembolic or cryptogenic stroke while adjusting for baseline demographics characteristics, clinical factors, echocardiographic left ventricular ejection fraction, and medication.

RESULTS

Over a median follow-up period of 1.63 years, 47 recurrent ischemic strokes (21 were cardioembolic or cryptogenic) occurred. In a multivariate model adjusted for potential confounders, compared with the bottom tertiles of LA diameter indexed to height (LA diameter/H), the top tertile of LA diameter/H was significantly associated with the total recurrent ischemic stroke (adjusted HR 3.610, 95% CI 1.870-6.967, p < .001) and the composite of recurrent cardioembolic or cryptogenic stroke (adjusted HR 5.673, 95% CI 1.780-18.084, p = .003). Results were similar when LA diameter indexed to body surface area (LA diameter/BSA) was involved in the analysis.

CONCLUSION

LA size is an independent predictor of total recurrent ischemic stroke and the composite of recurrent cardioembolic or cryptogenic stroke.

Association of CHADS2 and CHA2DS2-VASc Scores with Left Atrial Thrombus with Nonvalvular Atrial Fibrillation: A Single Center Based Retrospective Study in a Cohort of 2695 Chinese Subjects

The main mechanism of the CHADS₂ and CHA₂DS₂-VASc scores to predict stroke in nonvalvular atrial fibrillation (NVAF) is still controversial. We evaluated the association of the CHADS₂ and CHA₂DS₂-VASc scores with left atrial thrombus (LAT) as detected by transesophageal echocardiographic (TEE) and compared the predictive ability of these risk stratification schemes with nonvalvular atrial fibrillation (NVAF). Data from 2,695 consecutive NVAF patients in whom TEE was performed for screening LAT from July 2007 to February 2014 were analyzed. Only 3% of the subjects had LAT. Presence of LAT was not significantly associated with either CHADS₂  (P = 0.07) or CHA₂DS₂-VASc score (P = 0.12). The area under the curve (AUC) concerning LAT prediction using CHADS₂ and CHA₂DS₂-VASc was 0.574 and 0.569, respectively. A composition model includes previous stroke or transient ischemic attack, nonparoxysmal AF, moderate to severe left ventricular systolic dysfunction, left atrial enlargement, and cardiomyopathy which improved the discrimination significantly (AUC = 0.743). In our cohort, both CHADS₂ and CHA₂DS₂-VASc scores were of limited value for predicting LAT in patients with NVAF. This questions the CHADS₂/CHA₂DS₂-VASc score predicting stroke mainly through the mechanism of cardiogenic embolism. A scoring scheme combining clinical and echocardiographic parameters may better predict LAT as a surrogate for cardioembolic risk in NVAF patients.

Prediction of Early Recurrent Thromboembolic Event and Major Bleeding in Patients With Acute Stroke and Atrial Fibrillation by a Risk Stratification Schema: The ALESSA Score Study

BACKGROUND AND PURPOSES

This study was designed to derive and validate a score to predict early ischemic events and major bleedings after an acute ischemic stroke in patients with atrial fibrillation.

METHODS

The derivation cohort consisted of 854 patients with acute ischemic stroke and atrial fibrillation included in prospective series between January 2012 and March 2014. Older age (hazard ratio 1.06 for each additional year; 95% confidence interval, 1.00-1.11) and severe atrial enlargement (hazard ratio, 2.05; 95% confidence interval, 1.08-2.87) were predictors for ischemic outcome events (stroke, transient ischemic attack, and systemic embolism) at 90 days from acute stroke. Small lesions (≤1.5 cm) were inversely correlated with both major bleeding (hazard ratio, 0.39; P=0.03) and ischemic outcome events (hazard ratio, 0.55; 95% confidence interval, 0.30-1.00). We assigned to age ≥80 years 2 points and between 70 and 79 years 1 point; ischemic index lesion >1.5 cm, 1 point; severe atrial enlargement, 1 point (ALESSA score). A logistic regression with the receiver-operating characteristic graph procedure (C statistic) showed an area under the curve of 0.697 (0.632-0.763; P=0.0001) for ischemic outcome events and 0.585 (0.493-0.678; P=0.10) for major bleedings.

RESULTS

The validation cohort consisted of 994 patients included in prospective series between April 2014 and June 2016. Logistic regression with the receiver-operating characteristic graph procedure showed an area under the curve of 0.646 (0.529-0.763; P=0.009) for ischemic outcome events and 0.407 (0.275-0.540; P=0.14) for hemorrhagic outcome events.

CONCLUSIONS

In acute stroke patients with atrial fibrillation, high ALESSA scores were associated with a high risk of ischemic events but not of major bleedings.