Prevalence of and risk factors for silent ischemic stroke in patients with atrial fibrillation as determined by brain magnetic resonance imaging

Direct oral anticoagulants vs vitamin K antagonist on dementia risk in atrial fibrillation: systematic review with meta-analysis

Oral anticoagulation significantly reduces the incidence of dementia in atrial fibrillation patients. However, this protective effect has not been compared between Direct Oral Anticoagulants (DOAC) and Vitamin K antagonists' anticoagulants (VKA). We conducted an electronic search for potentially eligible studies through the bibliographic databases MEDLINE, CENTRAL, ClinicalTrials.gov, EMBASE and Web of Science. The outcome of interest was dementia. Random-effects meta-analysis was performed. Nine observational studies were included and 1,175,609 atrial fibrillation patients were enrolled. DOAC therapy was associated with a significant reduction when compared with patients under VKA therapy (hazard ratio 0.89; 95% confidence interval 0.80-0.99). The grade of confidence of our results was very low due to the risk of bias. DOAC therapy is associated with a significant decrease in the risk of dementia when compared with VKA therapy. However, the low certainty of the evidence along with the paucityof clinical trials dedicated to answering this important question underscores a need for global clinical research initiatives.

Silent cerebral lesions following catheter ablation for atrial fibrillation: a state-of-the-art review

Atrial fibrillation is associated with neurocognitive comorbidities such as stroke and dementia. Evidence suggests that rhythm control-especially if implemented early-may reduce the risk of cognitive decline. Catheter ablation is highly efficacious for restoring sinus rhythm in the setting of atrial fibrillation; however, ablation within the left atrium has been shown to result in MRI-detected silent cerebral lesions. In this state-of-the-art review article, we discuss the balance of risk between left atrial ablation and rhythm control. We highlight suggestions to lower the risk, as well as the evidence behind newer forms of ablation such as very high power short duration radiofrequency ablation and pulsed field ablation.

Covert Brain Infarction as a Risk Factor for Stroke Recurrence in Patients With Atrial Fibrillation

BACKGROUND

We aimed to evaluate covert brain infarction (CBI), frequently encountered during the diagnostic work-up of acute ischemic stroke, as a risk factor for stroke recurrence in patients with atrial fibrillation (AF).

METHODS

For this prospective cohort study, from patients with acute ischemic stroke hospitalized at 14 centers between 2017 and 2019, we enrolled AF patients without history of stroke or transient ischemic attack and divided them into the CBI (+) and CBI (-) groups. The 2 groups were compared regarding the 1-year cumulative incidence of recurrent ischemic stroke and all-cause mortality using the Fine and Gray subdistribution hazard model with nonstroke death as a competing risk and the Cox frailty model, respectively. Each CBI lesion was also categorized into either embolic-appearing (EA) or non-EA pattern CBI. Adjusted hazard ratios and 95% CIs of any CBI, EA pattern CBI only, non-EA pattern CBI only, and both CBIs were estimated.

RESULTS

Among 1383 first-ever stroke patients with AF, 578 patients (41.8%) had CBI. Of these 578 with CBI, EA pattern CBI only, non-EA pattern CBI only, and both CBIs were 61.8% (n=357), 21.8% (n=126), and 16.4% (n=95), respectively. The estimated 1-year cumulative incidence of recurrent ischemic stroke was 5.2% and 1.9% in the CBI (+) and CBI (-) groups, respectively (P=0.001 by Gray test). CBI increased the risk of recurrent ischemic stroke (adjusted hazard ratio [95% CI], 2.91 [1.44-5.88]) but did not the risk of all-cause mortality (1.32 [0.97-1.80]). The EA pattern CBI only and both CBIs elevated the risk of recurrent ischemic stroke (2.76 [1.32-5.77] and 5.39 [2.25-12.91], respectively), while the non-EA pattern only did not (1.44 [0.40-5.16]).

CONCLUSIONS

Our study suggests that AF patients with CBI might have increased risk of recurrent stroke. CBI could be considered when estimating the stroke risk in patients with AF.

Artificial Intelligence-Enabled Electrocardiogram for Atrial Fibrillation Identifies Cognitive Decline Risk and Cerebral Infarcts

OBJECTIVE

To investigate whether artificial intelligence-enabled electrocardiogram (AI-ECG) assessment of atrial fibrillation (AF) risk predicts cognitive decline and cerebral infarcts.

PATIENTS AND METHODS

This population-based study included sinus-rhythm ECG participants seen from November 29, 2004 through July 13, 2020, and a subset with brain magnetic resonance imaging (MRI) (October 10, 2011, through November 2, 2017). The AI-ECG score of AF risk calculated for participants was 0-1. To determine the AI-ECG-AF relationship with baseline cognitive dysfunction, we compared linear mixed-effects models with global and domain-specific cognitive z-scores from longitudinal neuropsychological assessments. The AI-ECG-AF score was logit transformed and modeled with cubic splines. For the brain-MRI subset, logistic regression evaluated correlation of the AI-ECG-AF score and the high-threshold, dichotomized AI-ECG-AF score with infarcts.

RESULTS

Participants (N=3729; median age, 74.1 years) underwent cognitive analysis. Adjusting for age, sex, education, and APOE ɛ4-carrier status, the AI-ECG-AF score correlated with lower baseline and faster decline in global-cognitive z-scores (P=.009 and P=.01, respectively, non-linear-based spline-models tests) and attention z-scores (P<.001 and P=.01, respectively). Sinus-rhythm-ECG participants (n=1373) underwent MRI. As a continuous measure, the AI-ECG-AF score correlated with infarcts but not after age and sex adjustment (P=.52). For dichotomized analysis, an AI-ECG-AF score greater than 0.5 correlated with infarcts (OR, 4.61; 95% CI, 2.45-8.55; P<.001); even after age and sex adjustment (OR, 2.09; 95% CI, 1.06-4.07; P=.03).

CONCLUSION

The AI-ECG-AF score correlated with worse baseline cognition and gradual global cognition and attention decline. High AF probability by AI-ECG-AF score correlated with MRI cerebral infarcts. However, most infarcts observed in our cohort were subcortical, suggesting that AI-ECG not only predicts AF but also detects other non-AF cardiac disease markers and correlates with small vessel cerebrovascular disease and cognitive decline.

A Retrospective Study of Perioperative Nursing Care of Patients After Percutaneous Left Atrial Appendage Occlusion

PURPOSE

To describe the retrospective audit examining nursing care of nonvalvular atrial fibrillation treated by percutaneous left atrial appendage closure (PLAAC).

DESIGN

PLAAC is a new technique for patients with atrial fibrillation unsuited for long-term oral anticoagulation treatment. The nursing care for patients treated by PLAAC has not yet been standardized.

METHODS

We performed a retrospective analysis of 259 patients with nonvalvular atrial fibrillation who underwent PLAAC in our department between August 2014 and June 2018. The data included preoperative evaluations, discussions, and preparations, including psychological care and atrial thrombosis screening; postoperative observations, including electrocardiograph monitoring; prevention and care of complications; administration of postoperative anticoagulation therapy; and postoperative education, including detailed discharge guidance and regular follow-up.

FINDINGS

All patients were discharged after 5-10 days of hospitalization. In the perioperative period, 4 cases (1.5%) developed serious complications, including 3 cases (1.2%) of delayed cardiac tamponade, cured by pericardial drainage, and 1 case of a suspected air embolism, which spontaneously recovered. During a mean follow-up period of 25.9 ± 7.9 months, all patients had good adherence to medical instructions and there were no cases of occluder displacement or shedding, thromboembolism, or severe bleeding complications.

CONCLUSIONS

The best therapeutic effect of PLAAC is strongly associated with the preoperative and postoperative training of nursing staff and the development of standard nursing procedures, including the establishment of observation and nursing manuals for complications. This study provides nursing practice information to aid in the standardization of nursing procedures for this new type of interventional therapy.

Long-Term Clinical Outcomes of Underdosed Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Atrial Flutter

BACKGROUND

Although direct oral anticoagulants (DOACs) have been shown to be effective at reducing the risk of stroke in patients with atrial fibrillation/flutter (AF), they are sometimes underdosed off-label to mitigate their associated higher bleeding risk. We sought to evaluate frequency and clinical outcomes of inappropriate underdosing of DOACS in patients with AF.

METHODS

We conducted a study of subjects with AF who had a clinical indication for stroke prophylaxis (with a congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack, vascular disease, age 65 to 47 years, sex category [CHA₂DS₂-VASc] of 2 or greater) and were prescribed 1 of the 4 clinically approved DOACs (apixaban, rivaroxaban, dabigatran, or edoxaban). We compared all-cause mortality, composite of stroke and systemic embolism, composite of myocardial infarction (MI), acute coronary syndromes (ACS), and coronary revascularization, and major bleeding between patients appropriately dosed and inappropriately underdosed.

RESULTS

A total of 8125 patients met inclusion criteria, with a mean follow up of 2.2 ± 2 years. Of those, 1724 patients (21.2%) were inappropriately dosed. After adjusting for baseline variables, there was no difference in all-cause mortality, risk of stroke or systemic embolism, International Society on Thrombosis and Haemostasis (ISTH) major bleeding, or composite of myocardial infarction, acute coronary syndromes, or coronary revascularization between patients appropriately dosed and inappropriately underdosed. In subgroup analysis, only apixaban demonstrated an increased incidence all-cause mortality (hazard ratio [HR] 1.24, 95% confidence interval [CI] 1.03-1.49) with inappropriate underdosing. There was no difference in the remaining clinical outcomes noted on subgroup analysis.

CONCLUSION

Underdosing of DOACs did not minimize risk of bleeding, systemic embolization or all-cause mortality in patients with AF. Inappropriate underdosing with apixaban in particular was associated with increased all-cause mortality.

Difference in risk factors of silent brain infarction between paroxysmal and persistent atrial fibrillation

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Differences in risk factors for SBI between paroxysmal and persistent AF was studied.

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NVAF patients (119 paroxysmal, 71 persistent) underwent brain MRI, TTE, and TEE.

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DM and CKD, which represents microvascular disease, predicted SBI in paroxysmal AF.

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There was no obvious therapeutic target for SBI after progression to persistent NVAF.

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Intervention for DM and CKD from paroxysmal NVAF may prevent SBI and future stroke.

Background

Although silent brain infarction is an independent risk factor for subsequent symptomatic stroke and dementia in patients with nonvalvular atrial fibrillation, little is known regarding differences in risk factors for silent brain infarction between patients with paroxysmal and persistent nonvalvular atrial fibrillation.

Methods

This study population consisted of 190 neurologically asymptomatic patients (mean age, 64 ± 11 years) with nonvalvular atrial fibrillation (119 paroxysmal, 71 persistent) who were scheduled for catheter ablation. All patients underwent brain magnetic resonance imaging to screen for silent brain infarction prior to ablation. Transthoracic and transesophageal echocardiography was performed to screen for left atrial abnormalities (left atrial enlargement, spontaneous echo contrast, or left atrial appendage emptying velocity) and complex plaques in the aortic arch.

Results

Silent brain infarction was detected in 50 patients (26%) [26 patients (22%) in paroxysmal vs. 24 patients (34%) in persistent, p = 0.09]. Multiple logistic regression analysis indicated that age and diabetes mellitus or chronic kidney disease (estimated glomerular filtration rate < 60 mL/min/1.73 m²) were associated with silent brain infarction in patients with paroxysmal nonvalvular atrial fibrillation (p < 0.05), whereas no modifiable risk factors of silent brain infarction were observed in patients with persistent nonvalvular atrial fibrillation.

Conclusions

These findings suggest that intensive intervention for diabetes mellitus and renal impairment from the paroxysmal stage or ablation therapy at the time of paroxysmal stage to prevent progression to persistent nonvalvular atrial fibrillation may prevent silent brain infarction and consequently reduce the risk of future symptomatic stroke.

Association of the CHA2D(S2)-VASc Score and Its Components With Overt and Silent Ischemic Brain Lesions in Patients With Atrial Fibrillation

Background: Silent and overt ischemic brain lesions are common and associated with adverse outcome. Whether the CHA₂DS₂-VASc score and its components predict magnetic resonance imaging (MRI)-detected ischemic silent and overt brain lesions in patients with atrial fibrillation (AF) is unclear.

Methods: In this cross-sectional analysis, patients with AF were enrolled in a multicenter cohort study in Switzerland. Outcomes were clinically overt, silent [in the absence of a history of stroke/transient ischemic attack (TIA)] and any MRI-detected ischemic brain lesions. Logistic regression analyses were performed to assess the relationship of the CHA₂DS₂-VASc score and its components with ischemic brain lesions. An adapted CHA₂D-VASc score (excluding history of stroke/TIA) for the analyses of clinically overt and silent ischemic brain lesions was used.

Results: Overall, 1,741 patients were included in the analysis (age 73 ± 8 years, 27.4% female). At least one ischemic brain lesion was observed in 36.8% (clinically overt: 10.5%; silent: 22.9%; transient ischemic attack: 3.4%). The CHA₂D-VASc score was strongly associated with clinically overt and silent ischemic brain lesions {odds ratio (OR) [95% confidence interval (CI)] 1.32 (1.17–1.49), p < 0.001 and 1.20 (1.10–1.30), p < 0.001, respectively}. Age 65–74 years (OR 2.58; 95%CI 1.29–5.90; p = 0.013), age ≥75 years (4.13; 2.07–9.43; p < 0.001), hypertension (1.90; 1.28–2.88; p = 0.002) and diabetes (1.48; 1.00–2.18; p = 0.047) were associated with clinically overt brain lesions, whereas age 65–74 years (1.95; 1.26–3.10; p = 0.004), age ≥75 years (3.06; 1.98–4.89; p < 0.001) and vascular disease (1.39; 1.07–1.79; p = 0.012) were associated with silent ischemic brain lesions.

Conclusions: A higher CHA₂D-VASc score was associated with a higher risk of both overt and silent ischemic brain lesions.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT02105844.

Long-term oral anticoagulant after catheter ablation for atrial fibrillation

Catheter ablation is superior to antiarrhythmic therapy for the reduction of symptomatic atrial fibrillation (AF), recurrence, and burden. The possibility of a true 'rhythm' control strategy with catheter ablation has re-opened the debate on rate vs. rhythm control and the subsequent impact on stroke risk. Some observation studies suggest that successful AF catheter ablation and maintenance of sinus rhythm are associated with a decrease in stroke risk, while the CABANA trial had demonstrated no apparent reduction. Other observational studies have demonstrated increased stroke risk when oral anticoagulation (OAC) is discontinued after catheter ablation. When and in whom OAC can be discontinued after ablation will need to be determined in properly conducted randomized control trials. In this review article, we discuss our current understanding of the interactions between AF, stroke, and anticoagulation following catheter ablation. Specifically, we discuss the evidence for the long-term anticoagulation following successful catheter ablation, the potential for OAC discontinuation with restoration of sinus rhythm, and novel approaches to anticoagulation management post-ablation.

The role of biomarkers and neuroimaging in ischemic/hemorrhagic risk assessment for cardiovascular/cerebrovascular disease prevention

Stroke prevention in patients with atrial fibrillation is arguably one of the fastest developing areas in preventive medicine. The increasing use of direct oral anticoagulants and nonpharmacologic methods such as left atrial appendage closure for stroke prevention in these patients has increased clinicians' options for optimal care. Platelet antiaggregants are also commonly used in other ischemic cardiovascular and or cerebrovascular conditions. Long term use of oral anticoagulants for atrial fibrillation is associated with elevated risks of major bleeds including especially brain hemorrhages, which are known to have extremely poor outcomes. Neuroimaging and other biomarkers have been validated to stratify brain hemorrhage risk among older adults. A thorough understanding of these biomarkers is essential for selection of appropriate anticoagulant or left atrial appendage closure for stroke prevention in patients with atrial fibrillation. This article will address advances in the stratification of ischemic and hemorrhagic stroke risk among patients with atrial fibrillation and other conditions.

Prevalence and risk factors of silent brain infarcts in patients with AF detected by 3T-MRI

BACKGROUND

Silent brain infarcts (SBI), a finding on neuroimaging, are associated with higher risk of future stroke. Atrial Fibrillation (AF) has been previously identified as a cause of SBI.

OBJECTIVES

The aim of this study is to determine the prevalence of and risk factors for SBI in patients with AF and low-to-moderate embolic risk according to CHADS₂ and CHA₂DS₂VASc score.

METHODS

Patients with a history of AF based on medical records who scored 0-1 in the CHADS₂ score were selected from the Seville urban area using the Andalusian electronic healthcare database (DIRAYA). Demographic and clinical data were collected and a 3T brain MRI was performed on patients older than 50 years and with absence of neurological symptoms.

RESULTS

66 of the initial 443 patients (14.9%) and 41 of the 349 patients with low risk according to CHA₂DS₂VASc score (11.7%) presented at least 1 SBI. After adjusted multivariable analysis, an older age (OR 3.84, 95% CI 1.07-13.76) and left atrial (LA) enlargement (OR 3.13, 95% CI 1.15-8.55) were associated with SBI in the whole cohort, while only LA enlargement was associated with SBI in the low-risk cohort (OR 3.19, 95% CI 1.33-7.63).

CONCLUSIONS

LA enlargement on echocardiogram was associated with SBI in patients with AF and low or moderate embolic risk according to CHADS₂ and in the low-risk population according to CHA₂DS₂VASc. Although further studies are needed, a neuroimaging screening might be justified in these patients to guide medical therapies to improve stroke prevention.

Management of periprocedural anticoagulant therapy: a novel individualized approach-a transeusophageal echocardiographic study

Patients with non-valvular atrial fibrillation who are under chronic oral anticoagulant therapy (OAC) treatment frequently require interruption of OAC treatment. By examining the presence of left atrial/left atrial appendage (LA/LAA) thrombus or dense spontaneous echo contrast (SEC) with transesophageal echocardiography (TEE) we aimed to develop an individualized strategy. To test the validity of CHA₂DS₂VASc score based recommendations was our secondary purpose. In this prospective study patients with non-valvular atrial fibrillation on OAC therapy were included. Patients' baseline characteristics, CHA₂DS₂VASc and HASBLED scores, medications, type of invasive procedures and clinical events were recorded. Each patient underwent to TEE examination prior to the invasive procedure. Bridging anticoagulation was recommended only to patients with LA/LAA thrombus. We included 155 patients and mean CHA₂DS₂VASc score of the study population was 3.4 ± 1.4. Seventy-one of them had LA/LAA thrombi or SEC on TEE examination and bridging anticoagulation was applied. OAC treatment was not bridged in 8 of 11 patients with prior cerebrovascular accident and 17 of 31 patients with CHA₂DS₂VASc score of > 4. 57 of 124 patients with CHA₂DS₂VASc score of ≤ 4 required bridging anticoagulation. There were 14 major bleedings decided according to ISTH bleeding classification. Major bleeding was observed only in patients underwent to high-risk bleeding procedure. In conclusion CHA₂DS₂VASc score by itself is not enough for decision-making regarding ischemic risk. Furthermore, since major bleedings occurred only in patients underwent to high-risk bleeding surgery, TEE-based individualisation may be a feasible approach particularly for those with high thromboembolic risk undergoing high-bleeding risk procedure.

Prognostic value of 99mTc-ECD brain perfusion SPECT in patients with atrial fibrillation and dementia

Background

Patients with atrial fibrillation (AF) and dementia experience reduced quality of life and increased mortality. Technetium 99m ECD brain perfusion single-photon emission computed tomography (^99mTc-ECD brain perfusion SPECT) is a beneficial modality for diagnosing dementia and identifying high-risk patients with mild cognitive impairment. The aim of this study was to evaluate the prognostic value of brain perfusion using ^99mTc-ECD SPECT in patients with AF and dementia.

Methods

Of a total of 405 consecutive patients diagnosed with AF as cardiac outpatients with dementia using the Mini-Mental State Examination by neurologists or psychiatrists, we identified 170 patients (81 ± 10 years) who underwent ^99mTc-ECD brain perfusion SPECT. Of them, 73, 73, and 24 were diagnosed with Alzheimer’s dementia (AD), vascular dementia (VD), and non-specified dementia, respectively. A multivariable Cox model was used to assess if higher Z-score by ^99mTc-ECD brain perfusion SPECT and clinical parameters were associated with major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, hospitalization for heart failure, and stroke.

Results

During a mean follow-up of 1258 ± 1044 days, 62 MACE occurred. There was no significant difference in MACE between AD and VD (33%, vs. 44%, p = 0.153). The multivariable Cox model confirmed that the higher Z-score of temporo-parieto-occipital lobe was associated with increased MACE compared to the lower group (HR 2.521, 95% CI 1.465–4.337, p < 0.001).

Conclusion

This study demonstrated that decreased cerebral blood flow in the temporo-parieto-occipital lobe could be a potential prognostic value in patients with both AF and dementia.

Ischemic Stroke Risk in Patients With Nonvalvular Atrial Fibrillation: JACC Review Topic of the Week

The last decade has witnessed remarkable advances in pharmacological and nonpharmacological strategies for stroke prevention in patients with atrial fibrillation. However, the currently available clinical stroke risk prediction models do not account for key nonclinical factors (arrhythmia burden, left atrial physiology and anatomy, chemical and electrocardiographic markers) and other competing clinical risks. Hence, their ability to identify patients who will derive the most benefit from pharmacological and mechanical risk prevention strategies remain limited. In this paper, the authors review the current and evolving ischemic stroke risk prediction schemes in patients with nonvalvular atrial fibrillation, highlight the strengths and weaknesses of the models, and discuss the unmet needs in this field.

Cognitive dysfunction in atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia in adults, and its incidence and prevalence increase with age. The risk of cognitive impairment and dementia also increases with age, and both AF and cognitive impairment or dementia share important risk factors. In meta-analyses of published studies, AF is associated with a 2.4-fold and 1.4-fold increase in the risk of dementia in patients with or without a history of stroke, respectively. This association is independent of shared risk factors such as hypertension and diabetes mellitus. Neuroimaging has illustrated several potential mechanisms of cognitive decline in patients with AF. AF is associated with increased prevalence of silent cerebral infarcts, and more recent data also suggest an increased prevalence of cerebral microbleeds with AF. AF is also associated with a pro-inflammatory state, and the relationship between AF-induced systemic inflammation and dementia remains to be investigated. Preliminary reports indicate that anticoagulation medication including warfarin can reduce the risk of cognitive impairment in patients with AF. Catheter ablation, increasingly used to maintain sinus rhythm in patients with AF, is associated with the formation of new silent cerebral lesions. The majority of these lesions are not detectable after 1 year, and insufficient data are available to evaluate their effect on cognition. Large prospective studies are urgently needed to confirm the association between AF and dementia, to elucidate the associated mechanisms, and to investigate the effect of anticoagulation and rhythm control on cognition.

MRI-detected brain lesions in AF patients without further stroke risk factors undergoing ablation - a retrospective analysis of prospective studies

BACKGROUND

Atrial fibrillation (AF) without other stroke risk factors is assumed to have a low annual stroke risk comparable to patients without AF. Therefore, current clinical guidelines do not recommend oral anticoagulation for stroke prevention of AF in patients without stroke risk factors. We analyzed brain magnetic resonance imaging (MRI) imaging to estimate the rate of clinically inapparent ("silent") ischemic brain lesions in these patients.

METHODS

We pooled individual patient-level data from three prospective studies comprising stroke-free patients with symptomatic AF. All study patients underwent brain MRI within 24-48 h before planned left atrial catheter ablation. MRIs were analyzed by a neuroradiologist blinded to clinical data.

RESULTS

In total, 175 patients (median age 60 (IQR 54-67) years, 32% female, median CHA₂DS₂-VASc = 1 (IQR 0-2), 33% persistent AF) were included. In AF patients without or with at least one stroke risk factor, at least one silent ischemic brain lesion was observed in 4 (8%) out of 48 and 10 (8%) out of 127 patients, respectively (p > 0.99). Presence of silent ischemic brain lesions was related to age (p = 0.03) but not to AF pattern (p = 0.77). At least one cerebral microbleed was detected in 5 (13%) out of 30 AF patients without stroke risk factors and 25 (25%) out of 108 AF patients with stroke risk factors (p = 0.2). Presence of cerebral microbleeds was related to male sex (p = 0.04) or peripheral artery occlusive disease (p = 0.03).

CONCLUSION

In patients with symptomatic AF scheduled for ablation, brain MRI detected silent ischemic brain lesions in approximately one in 12 patients, and microbleeds in one in 5 patients. The prevalence of silent ischemic brain lesions did not differ in AF patients with or without further stroke risk factors.

Validation of Conventional Thromboembolic Risk Factors in a Korean Atrial Fibrillation Population - Suggestion for a Novel Scoring System, CHA2DS2-VAK

BACKGROUND

There is little evidence that focuses on the ethnic variability of clinical risk factors for thromboembolism (TE) in atrial fibrillation (AF). We aimed to investigate the effect of each traditional risk factor in the Korean AF population.

METHODS AND RESULTS

Medical records of 12,876 consecutive patients (aged >18 years) newly diagnosed and followed up with non-valvular AF from 2000 to 2013 were reviewed. TE events, including ischemic stroke and systemic embolism, were investigated for risk factor validation. Among the total of 12,876 patients, 1,390 (10.8%) had TE events. In univariate/multivariate analysis adjusting for clinical factors and antithrombotic medications, traditional risk factors included in the CHA2DS2-VASc scheme showed statistical significance, except for female sex, which was not a predictor of events. Additionally, chronic kidney disease (CKD; hazard ratio 1.62, P<0.001) was shown to be an independent predictor of TE events. Based on the analysis, we developed a novel stratification system, CHA2DS2-VAK, omitting the female sex category and adding CKD. The new scoring system showed greater discrimination in event rates between score 0 and 1 patients.

CONCLUSIONS

Female sex was not associated with TE events in a Korean non-valvular AF population. The novel CHA2DS2-VAK scoring system, with substitution of CKD for female sex, might be more appropriate for the Korean population.

Association between red cell distribution width and thromboembolic events in patients with atrial fibrillation

BACKGROUND

We investigated whether an increase in the value of red cell distribution width (RDW) was associated with thromboembolic outcomes in patients with atrial fibrillation (AF).

METHODS

We performed a retrospective analysis of 5082 consecutive patients with non-valvular AF. Thromboembolic events (N=723, 14.2%) were recorded and analysed according to RDW value.

RESULTS

The peak RDW value during follow-up was higher in patients with thromboembolic events than in those without thromboembolic events (15.1% vs. 14.2%, p<0.001). The RDW value showed similar power in predicting thromboembolic outcomes compared with the factor of age. The risk of thromboembolic events was higher in patients with a peak RDW≥13.9% than in patients with a peak RDW<13.9% (hazard ratio 1.63, p<0.001), and increased with each quartile increase of RDW. In a subgroup of 739 patients with congestive heart failure (CHF), there were 112 (15.2%) thromboembolic events. The peak RDW value of patients with CHF with thromboembolic events was also significantly higher (16.4% vs. 15.6%, p=0.019) compared to that of those without thromboembolic events.

CONCLUSION

An increased RDW value during follow-up could be associated with thromboembolic events in patients with non-valvular AF. The suggested cut-off values for RDW used to predict an increased thromboembolic risk in were ≥13.9% in patients with AF in general, ≥15% in patients with co-existing AF and CHF.

The Global Burden of Atrial Fibrillation and Stroke: A Systematic Review of the Clinical Epidemiology of Atrial Fibrillation in Asia

BACKGROUND

Our previous review reported great variability in the incidence and prevalence of atrial fibrillation (AF) in non-Western cohorts, especially from Asian countries; in recent years, epidemiologic studies on AF have been increasingly reported from Asia.

METHODS

The goal of this updated systematic review was to present the current knowledge base of AF epidemiology in Asian countries since our previous review. We also explored AF incidence and the risk of stroke in AF by using a meta-analysis, with I² testing the heterogeneity. Third, "real-world" antithrombotic drug use for ischemic stroke (IS) prevention associated with AF was studied.

RESULTS

A total of 58 articles from eight countries in Asia were included in the analysis. The summary annual incidence of AF was 5.38 (95% CI, 4.53-6.24; I² = 99.5%; n = 10) per 1,000 person-years, and the IS annual risk in AF was 3.0% (1.60%-4.95%; I² = 99.8%; n = 8) when meta-analysis was performed on hospital- and community-based studies. Hospital- and community-based AF prevalence ranged from 0.37% to 3.56% and 2.8% to 15.8%, respectively. IS prevalence in AF ranged from 1.9% to 6.0% and 0.36% to 28.3% in community- and hospital-based studies. Warfarin use in Chinese subjects is relatively low (1.0%-4.1%) compared with Japanese subjects (49.1%-70.0%) in community-based studies. The rate of warfarin use was < 50% in hospital-based studies.

CONCLUSIONS

The incidence and prevalence of AF have increased in recent years, although great variability still exists in Asian countries. Variability in annual IS risk in patients with AF was apparent between hospital- and community-based studies. However, the rate of warfarin use was < 50% in hospital studies from Asian countries.

Apixaban for treatment of embolic stroke of undetermined source (ATTICUS randomized trial): Rationale and study design

Rationale

Optimal secondary prevention of embolic stroke of undetermined source is not established. The current standard in these patients is acetylsalicylic acid, despite high prevalence of yet undetected paroxysmal atrial fibrillation.

Aim

The ATTICUS randomized trial is designed to determine whether the factor Xa inhibitor apixaban administered within 7 days after embolic stroke of undetermined source, is superior to acetylsalicylic acid for prevention of new ischemic lesions documented by brain magnetic resonance imaging within 12 months after index stroke.

Design

Prospective, randomized, blinded, parallel-group, open-label, German multicenter phase III trial in approximately 500 patients with embolic stroke of undetermined source. A key inclusion criterion is the presence or the planned implantation of an insertable cardiac monitor. Patients are 1:1 randomized to apixaban or acetylsalicylic acid and treated for a 12-month period. It is an event-driven trial aiming for core-lab adjudicated primary outcome events.

Study outcomes

The primary outcome is the occurrence of at least one new ischemic lesion identified by axial T2-weighted FLAIR magnetic resonance imaging and/or axial DWI magnetic resonance imaging at 12 months when compared with the baseline magnetic resonance imaging. Key secondary outcomes are the combination of recurrent ischemic strokes, hemorrhagic strokes, systemic embolism; combination of MACE including recurrent stroke, myocardial infarction, and cardiovascular death and combination of major and clinically relevant non-major bleeding defined according to ISTH, and change of cognitive function and quality of life (EQ-5D, Stroke Impact Scale).

Discussion

Embolic stroke of undetermined source is caused by embolic disease and associated with a high risk of recurrent ischemic strokes and clinically silent cerebral ischemic lesions. ATTICUS will investigate the impact of atrial fibrillation detected by insertable cardiac monitor and the effects of early anticoagulation with apixaban compared with antiplatelet therapy with acetylsalicylic acid on the incidence of new ischemic lesion after embolic stroke of undetermined source.

The Mechanism of and Preventive Therapy for Stroke in Patients with Atrial Fibrillation

Atrial fibrillation is a major cardiac cause of stroke, and a pathogenesis involving thrombus formation in patients with atrial fibrillation is well established. A strategy for rhythm control that involves catheter ablation and anticoagulation therapy is evolving. A strategy for rhythm control that restores and maintains sinus rhythm should reduce the risk of ischemic stroke that is associated with atrial fibrillation; however, this is yet to be proven in large-scale randomized controlled trials. This paper reviews the emerging role of rhythm control therapy for atrial fibrillation to prevent stroke.

Almanac 2015: atrial fibrillation research in Heart

Atrial fibrillation continues to attract interest in the cardiovascular community and in Heart. Over 60 original research and review papers published in Heart in 2014–2015 cover various aspects of atrial fibrillation, from associated conditions and precipitating factors to new approaches to management. Here, we provide an overview of articles on atrial fibrillation published in Heart in 2014–2015, highlighting new developments, emerging concepts and novel approaches to treatment.

Atrial fibrillation, cognitive impairment, and neuroimaging

INTRODUCTION

The objective of our study was to investigate cross-sectional associations of atrial fibrillation with neuroimaging measures of cerebrovascular disease and Alzheimer's disease and their interactions with mild cognitive impairment (MCI).

METHODS

Magnetic resonance imaging scans of individuals from a population-based study were analyzed for infarctions, total gray matter, and hippocampal and white matter hyperintensity volumes. A subsample underwent positron emission tomography imaging.

RESULTS

Atrial fibrillation was associated with infarctions and lower total gray matter volume. Compared with subjects with no atrial fibrillation and no infarction, the odds ratio (95% confidence intervals) for MCI was 2.99 (1.57-5.70; P = .001) among participants with atrial fibrillation and infarction, 0.90 (0.45-1.80; P = .77) for atrial fibrillation and no infarction, and 1.50 (0.96-2.34; P = .08) for no atrial fibrillation and any infarction.

DISCUSSION

Participants with both atrial fibrillation and infarction are more likely to have MCI than participants with either infarction or atrial fibrillation alone.

Predictors of silent brain infarction on magnetic resonance imaging in patients with nonvalvular atrial fibrillation: A transesophageal echocardiographic study

BACKGROUND

Silent brain infarction (SBI) is often found in patients with atrial fibrillation (AF) and may be related to cognitive decline. We investigated the predictors of SBI on brain magnetic resonance imaging (MRI) using transesophageal echocardiography (TEE) in patients with nonvalvular AF.

METHODS

The study population consisted of 103 neurologically asymptomatic patients with nonvalvular AF who underwent TEE before transcatheter AF ablation (76 men; mean age 63 ± 10 years). Left atrial (LA) abnormalities such as LA thrombus, spontaneous echo contrast, or abnormal LA appendage emptying velocity (<20 cm/s) and complex plaques in the aortic arch defined as large plaques ≥4 mm thickness, ulcerated plaques, or mobile plaques were evaluated by TEE. All patients were screened for SBI by brain MRI.

RESULTS

Of 103 patients, 31 (30%) showed SBI on brain MRI. Most lesions were multiple (61%) and small (<15 mm) in diameter (84%). Patients with SBI had a higher prevalence of LA abnormalities (45% vs 14%; P < .001) and complex arch plaques (45% vs 7%; P < .001) compared with those without SBI. In a multivariate logistic regression analysis including age and CHADS2 score ≥2, LA abnormalities (odds ratio 4.13; 95% CI 1.34-12.72; P = .014) and complex arch plaques (odds ratio 4.82; 95% CI 1.23-18.92; P = .024) were independent predictors of SBI.

CONCLUSIONS

Left atrial abnormalities and complex arch plaques detected by TEE were closely associated with the presence of SBI on brain MRI, suggesting that microembolization of small thrombi derived from the fibrillating LA or advanced aortic atherosclerotic lesions may be important causes of SBI in patients with nonvalvular AF.

Epidemiology of atrial fibrillation: European perspective

In the last 20 years, atrial fibrillation (AF) has become one of the most important public health problems and a significant cause of increasing health care costs in western countries. The prevalence of AF is increasing due to our greater ability to treat chronic cardiac and noncardiac diseases, and the improved ability to suspect and diagnose AF. At the present time, the prevalence of AF (2%) is double that reported in the last decade. The prevalence of AF varies with age and sex. AF is present in 0.12%–0.16% of those younger than 49 years, in 3.7%–4.2% of those aged 60–70 years, and in 10%–17% of those aged 80 years or older. In addition, it occurs more frequently in males, with a male to female ratio of 1.2:1. The incidence of AF ranges between 0.21 and 0.41 per 1,000 person/years. Permanent AF occurs in approximately 50% of patients, and paroxysmal and persistent AF in 25% each. AF is frequently associated with cardiac disease and comorbidities. The most common concomitant diseases are coronary artery disease, valvular heart disease, and cardiomyopathy. The most common comorbidities are hypertension, diabetes, heart failure, chronic obstructive pulmonary disease, renal failure, stroke, and cognitive disturbance. Paroxysmal AF occurs in younger patients and with a reduced burden of both cardiac disease and comorbidities. Generally, the history of AF is long, burdened by frequent recurrences, and associated with symptoms (in two thirds of patients). Patients with AF have a five-fold and two-fold higher risk of stroke and death, respectively. We estimate that the number of patients with AF in 2030 in Europe will be 14–17 million and the number of new cases of AF per year at 120,000–215,000. Given that AF is associated with significant morbidity and mortality, this increasing number of individuals with AF will have major public health implications.