Atrial Fibrillation and Cognitive Decline

Exploring the Link between Anticoagulation, Cognitive Impairment and Dementia in Atrial Fibrillation: A Systematic Review

Background: The impact of oral anticoagulants (OACs) on cognitive impairment and dementia in patients with atrial fibrillation (AF) is not well characterized. This systematic review aims to address this knowledge gap. Methods: SCOPUS and PubMed searches were conducted to identify articles in the English language investigating the association between the use of OACs and cognitive impairment and dementia. We excluded non-original research studies and studies that did not report data on cognitive impairment or included patients who underwent open heart surgery or had psychiatric illnesses or cancer. Results: Out of 22 studies (n = 606,404 patients), 13 studies (n = 597,744 patients) reported a reduction in cognitive impairment/dementia in those undergoing thromboprophylaxis. Using direct oral anticoagulants (DOACs) was associated with a lower incidence of cognitive impairment in 10 studies (n = 284,636 patients). One study found that patients undergoing dual therapy (n = 6794 patients) had a greater incidence of cognitive impairment compared to those undergoing monotherapy (n = 9994 patients). Three studies (n = 61,991 patients) showed that AF patients on DOACs had a lower likelihood of dementia diagnosis than those on vitamin K antagonists (VKAs). Dementia incidence was lower when VKAs were under good control. Conclusions: The use of oral anticoagulants has the potential to prevent cognitive impairment and dementia in patients with AF. Since most of the published research on this subject is observational in nature, more randomized controlled trials are needed to fully understand the effect of anticoagulants on cognitive function.

Atrial Fibrillation and Dementia: Focus on Shared Pathophysiological Mechanisms and Therapeutic Implications

OBJECTIVES

Atrial fibrillation (AF) and dementia are highly prevalent chronic and debilitating conditions, especially affecting the older population. This review focuses on possible common pathophysiological mechanisms that could explain the association between the 2 conditions.

DESIGN

Narrative review.

SETTING AND PARTICIPANTS

Evidence from epidemiologic, observational, and interventional studies evaluating prevalence and incidence of cognitive impairment in patients with AF.

METHODS

Broad literature search between December 2022 and May 2023. Eligible categories for inclusion comprised interventional studies, observational studies, systematic reviews, and meta-analysis.

RESULTS

Evidence from different cohorts has shown that AF increases the risk of dementia, although the association with dementia subtypes is not always unequivocal. According to recent evidence, common pathophysiological mechanisms include thromboembolism and hypercoagulable states, proinflammatory state, infection, cerebral hypoperfusion, and brain atrophy. Moreover, we reviewed the evidence on therapeutic measures to prevent dementia in patients with AF.

CONCLUSIONS AND IMPLICATIONS

Screening for cognition in patients with AF is of paramount importance, given the shared risk factors and common pathophysiological mechanisms. More evidence is needed to clarify whether antiarrhythmic and anticoagulant therapy have an impact on cognitive outcomes in AF patients.

Heart rate fragmentation and brain MRI markers of small vessel disease in MESA

INTRODUCTION

Heart rate (HR) fragmentation indices quantify breakdown of HR regulation and are associated with atrial fibrillation and cognitive impairment. Their association with brain magnetic resonance imaging (MRI) markers of small vessel disease is unexplored.

METHODS

In 606 stroke-free participants of the Multi-Ethnic Study of Atherosclerosis (mean age 67), HR fragmentation indices including percentage of inflection points (PIP) were derived from sleep study recordings. We examined PIP in relation to white matter hyperintensity (WMH) volume, total white matter fractional anisotropy (FA), and microbleeds from 3-Tesla brain MRI completed 7 years later.

RESULTS

In adjusted analyses, higher PIP was associated with greater WMH volume (14% per standard deviation [SD], 95% confidence interval [CI]: 2, 27%, P = 0.02) and lower WM FA (-0.09 SD per SD, 95% CI: -0.16, -0.01, P = 0.03).

DISCUSSION

HR fragmentation was associated with small vessel disease. HR fragmentation can be measured automatically from ambulatory electrocardiogram devices and may be useful as a biomarker of vascular brain injury.

Cerebrovascular, Cognitive and Cardiac Benefits of SGLT2 Inhibitors Therapy in Patients with Atrial Fibrillation and Type 2 Diabetes Mellitus: Results from a Global Federated Health Network Analysis

BACKGROUND

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are effective anti-diabetic drugs improving cardiovascular outcomes in type 2 diabetes mellitus (T2DM) patients. This study investigated cardiovascular, cerebrovascular and cognitive outcomes of SGLT2i therapy in patients with atrial fibrillation (AF) and T2DM.

METHODS

Observational study using TriNetX, a global health research network of anonymised electronic medical records from real-world patients between January 2018 and December 2019. The network includes healthcare organisations globally but predominately in the United States. AF patients (ICD-10-CM code: I48) with T2DM were divided according to SGLT2i use or not, and balanced using propensity score matching (PSM). Patients were followed-up for 3-years. The primary endpoints were ischaemic stroke/transient ischemic attack (TIA), intracranial haemorrhage (ICH), and incident dementia. Secondary endpoints were incident heart failure and mortality.

RESULTS

We identified 89,356 AF patients with T2DM of which 5061 (5.7%) were taking a SGLT2i. After PSM, 5049 patients (mean age 66.7 ± 10.6 years; 28.9% female) were included in each group. At 3-years follow-up, the risk of ischaemic stroke/TIA was higher in patients not receiving SGLT2i (HR 1.12, 95% CI 1.01-1.24) and for ICH (HR 1.57, 95% CI 1.25-1.99) and incident dementia (HR 1.66, 95% CI 1.30-2.12). Incident heart failure (HR 1.50, 95% CI 1.34-1.68) and mortality (HR 1.77, 95% CI 1.58-1.99) risks were increased in AF patients not receiving SGLT2i.

CONCLUSIONS

In our large 'real world' analysis of patients with concomitant AF and T2DM, SGLT2i reduced the risk of cerebrovascular events, incident dementia, heart failure and death.

Prevalence and factors associated with cognitive impairment in Chinese heart failure patients: A pilot study

Background

The prevalence of Cognitive impairment (CI) is high in patients with heart failure (HF). It leads to poor prognosis, such as self-care, hospital readmission and increased mortality. However, such information among Chinese population is unclear.

Objective

The purpose of this study was to examine the prevalence of CI in Chinese patients with HF, and explore its correlation with biomarkers and clinical factors to better manage HF patients with CI.

Methods

This study is a cross-sectional study of 200 hospitalized HF patients in China. The cognitive function of HF patients was assessed by the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE).

Results

The majority are male (62.5%, n = 125), have primary school and below level of education (57.5%, n = 115), NYHA III and above (62%, n = 124). They have an average MoCA score of 15.10 ± 8.18, MMSE score of 19.55 ± 8.23. Age, NYHA class, and atrial fibrillation were independently associated with CI (p < 0.05). There was a significant association between CI and the 4th quartile of TNT (p = 0.013), and the 3rd and 4th quartile of NT-proBNP (p = 0.015, p = 0.038).

Conclusions

The prevalence of undiagnosed CI in Chinese HF patients is high (81%). HF patients with high levels of TNT or NT-proBNP or both values may be at risk of developing CI. Therefore, we suggest that HF patients with older age, atrial fibrillation, NYHA class II and III, as well as elevated TNT or NT-proBNP or both values to be followed up with a formal evaluation for CI. Nurses need to provide targeted health education program for cognitively impaired HF population to improve their self-care ability and nursing outcome.

Improved brain perfusion after electrical cardioversion of atrial fibrillation

AIMS

Atrial fibrillation (AF) has been associated with reduced brain volume, cognitive impairment, and reduced cerebral blood flow. The causes of reduced cerebral blood flow in AF are unknown, but no reduction was seen in individuals without the arrhythmia in a previous study. The aim of this study was to test the hypothesis that brain perfusion, measured with magnetic resonance imaging (MRI), improves after cardioversion of AF to sinus rhythm (SR).

METHODS AND RESULTS

All patients undergoing elective cardioversion at our institution were invited to participate. A total of 44 individuals were included. Magnetic resonance imaging studies were done before and after cardioversion with both brain perfusion and cerebral blood flow measurements. However, 17 did not complete the second MRI as they had a recurrence of AF during the observation period (recurrent AF group), leaving 17 in the SR group and 10 in the AF group to complete both measurements. Brain perfusion increased after cardioversion to SR by 4.9 mL/100 g/min in the whole brain (P < 0.001) and by 5.6 mL/100 g/min in grey matter (P < 0.001). Cerebral blood flow increased by 58.6 mL/min (P < 0.05). Both brain perfusion and cerebral blood flow remained unchanged when cardioversion was unsuccessful.

CONCLUSION

In this study of individuals undergoing elective cardioversion for AF, restoration, and maintenance of SR for at least 10 weeks after was associated with an improvement of brain perfusion and cerebral blood flow measured by both arterial spin labelling and phase contrast MRI. In those individuals where cardioversion was unsuccessful, there was no change in perfusion or blood flow.

Hyperintense Brain Lesions in Asymptomatic Low Risk Patients with Paroxysmal Atrial Fibrillation Undergoing Radiofrequency Pulmonary Vein Isolation

BACKGROUND

The aim was to determine the occurrence, consequences and risk factors for brain white matter hyperintensities (WMH) assessed in magnetic resonance imaging (MRI) in low-risk patients with paroxysmal atrial fibrillation (AF) undergoing radiofrequency pulmonary vein isolation (PVI-RF).

METHODS

74 patients with AF (median 58.5 years (IQR 50-63), 45 male) were included. Before and after a minimum of 6 months after PVI-RF, a brain MRI and a mini-mental state examination (MMSE) were performed.

RESULTS

Baseline WMH lesions were found in 55 (74.3%) patients and in 48 from 62 (77.4%) patients after PVI-RF. The WMH lesions were more frequent among older patients, with a higher CHA2DS2-Vasc (C-Congestive heart failure/LV dysfunction, H-Hypertension, A-Age, D-Diabetes mellitus, S-Stroke, V-Vascular Disease, Sc-Sex category). Factors affecting the severity of the WMH were: older age, the co-existence of the PFO and coronary artery disease (CAD). After a follow-up period, the factors predisposing to brain WMH lesions occurrence (age, higher BMI and CHA2DS2-Vasc score) and to the more advanced changes (age, higher CHA2DS2-Vasc score, CAD, PFO) were obtained.

CONCLUSIONS

The presence and severity of cerebral microembolism are associated with age, higher CHA2DS2-Vasc score and the coexistence of PFO and CAD. PVI-RF procedure and its efficacy does not influence on MRI lesions. In this population, cerebral microembolism is not related to cognitive impairment.

Atrial fibrillation: villain or bystander in vascular brain injury

Atrial fibrillation (AF) and stroke are inextricably connected, with classical Virchow pathophysiology explaining thromboembolism through blood stasis in the fibrillating left atrium. This conceptualization has been reinforced by the remarkable efficacy of oral anticoagulant (OAC) for stroke prevention in AF. A number of observations showing that the presence of AF is neither necessary nor sufficient for stroke, cast doubt on the causal role of AF as a villain in vascular brain injury (VBI). The requirement for additional risk factors before AF increases stroke risk; temporal disconnect of AF from a stroke in patients with no AF for months before stroke during continuous ECG monitoring but manifesting AF only after stroke; and increasing recognition of the role of atrial cardiomyopathy and atrial substrate in AF-related stroke, and also stroke without AF, have led to rethinking the pathogenetic model of cardioembolic stroke. This is quite separate from recognition that in AF, shared cardiovascular risk factors can lead both to non-embolic stroke, or emboli from the aorta and carotid arteries. Meanwhile, VBI is now expanded to include dementia and cognitive decline: research is required to see if reduced by OAC. A changed conceptual model with less focus on the arrhythmia, and more on atrial substrate/cardiomyopathy causing VBI both in the presence or absence of AF, is required to allow us to better prevent AF-related VBI. It could direct focus towards prevention of the atrial cardiomyopathy though much work is required to better define this entity before the balance between AF as villain or bystander can be determined.

Atrial Fibrillation and Cognitive Function: JACC Review Topic of the Week

Numerous vascular risk factors and vascular diseases contribute to cognitive impairment and dementia. Many studies and registries show an association of atrial fibrillation (AF) with cognitive impairment, cognitive decline, and dementia. This is true for vascular dementia and Alzheimer's disease. The assumed multifactorial mechanisms include ischemic stroke, both apparent and silent, cerebral microinfarcts, cerebral hemorrhage, and reduced cerebral blood flow. A number of retrospective observational and prospective studies support that anticoagulation in patients with AF may reduce the risk of cognitive decline and dementia. This holds for both vitamin K antagonists (e.g., warfarin) and direct oral anticoagulants. However, it still remains unproven if anticoagulation reduces cognitive decline and dementia in AF patients based on randomized trials.

Increase in regional cerebral saturation after elective electrical cardioversion of atrial fibrillation is only transient and without beneficial effects on neuropsychological functioning: cerebral saturation during electrical cardioversion

We aimed to confirm the positive association between a successful electrical cardioversion (ECV) and increase in SctO₂ and investigated whether this increase is persisting or not. Secondary, the influence of a successful ECV on the neuropsychological function and the association with SctO₂ was assessed as well. SctO₂ was measured continuously during elective ECV using near-infrared spectroscopy. Measurements started before induction of sedation and ended 15 min after awakening. A second measurement took place 4 to 6 weeks after ECV. To assess neuropsychological functioning, patients performed standardized neuropsychological tests before ECV and at follow-up and were compared to healthy volunteers as control group. SctO₂ was measured in 60 patients during elective ECV. ECV was successful in 50 AF patients, while in ten patients sinus rhythm was not obtained. SctO₂ increased immediately after successful ECV in 50 patients (1% (- 5 to 4); p = 0.031), but not after unsuccessful ECV in 10 patients (- 1% (- 5;3); p = 0.481). This SctO₂ change was positively correlated with the instant change in blood pressure (R² = 0.391; p = 0.004). At follow-up, SctO₂ values were no longer increased. Nevertheless, successful ECV improved the patient's quality of life but did not influence neuropsychological functioning at follow-up. A transient, instant SctO₂ increase was observed after successful ECV. This temporary increase in SctO₂ did not influence the neuropsychological functioning of the patients. Though, the quality of life of patients with a successful ECV improved.

Anticoagulant Therapy as a Tool for the Prevention of Cognitive Impairment Associated with Atrial Fibrillation

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias in clinical practice and important additional risk factor for the development of cognitive impairment (CI) and dementia as it has been shown in recent studies. According to the Diagnostic and statistical manual of mental disorders latest revision CI refers to a decrease of one or more higher cortical functions that provide the processes of perception, storage, transformation and transmission of information compared to the premorbid level. The main hypothesis that explains the relationship between AF and dementia is the assumption that in the presence of this arrhythmia a brain substance is damaged due to microembolism and cerebral microbleeding. The high clinical significance of AF as well as CI served as a background for the development by European experts several consensus documents concerning the problem of the relationships between these conditions. In addition, they emphasize the role of anticoagulant therapy as a preventing tool for the development of stroke, which can be a factor in the CI progression in patients with AF, with particular priority to direct oral anticoagulants (DOACs). In randomized clinical trials, meta-analyses and systematic reviews have been shown that the use of DOACs, as compared to vitamin K antagonists, is a more rational strategy for preventing stroke associated with AF. Among the DOAC class, rivaroxaban is worth noticing as a drug that has a favorable efficacy profile for primary and secondary stroke prevention. Rivaroxaban distinguishing characteristics are a once daily administration as well as a calendar package which is practically important for patients with CI.

[Cognitive Dysfunction at the Background of Atrial Fibrillation: Clinical-Pathological Aspects, Diagnostics and Prevention, Issues of the Use of the Application of Anticoagulant Therapy]

Atrial fibrillation (AF) and cognitive dysfunction - common states with similar risk factors. Recently significant scientific epidemiological data has been received in favor of independence of effect of AF on possibility of development of cognitive dysfunction. In this review we present problems of prevalence, pathogenesis, and diagnostics of various variants of cognitive disorders at the background of AF, as well as methods of their prevention and tactics of anticoagulant therapy in the presence of cognitive disturbances.

Atrial Fibrillation, Cognitive Decline, and Dementia: an Epidemiologic Review

PURPOSE OF REVIEW

Atrial fibrillation (AF) and dementia are both prevalent diseases in aging societies, which exert a great economic burden worldwide. Although a handful of epidemiologic studies have indicated that AF is independently associated with faster cognitive decline and a higher risk of dementia, there is still a lack of comprehensive understanding of the observed association. In this review, we summarize evidence from major epidemiologic studies concerning AF-related cognitive decline and dementia, the potential mechanisms underlying their association, and the cognitive benefits of treatment options.

RECENT FINDINGS

A large majority of population-based longitudinal studies have consistently shown an independent association of AF with cognitive decline and dementia with varying effect sizes, depending on the age of the study population and the presence of clinical stroke. The underlying pathways linking AF to cognitive phenotypes may involve systemic inflammation, cerebral hypoperfusion, and cerebral small vessel disease and microemboli. However, current evidence is insufficient to support the potential benefits of AF treatment in reducing risk of cognitive decline and dementia.

SUMMARY

Current epidemiologic research suggests that AF contributes to cognitive decline and dementia, independent of a history of stroke. Further work is warranted to elucidate the potential mechanisms underlying this association, and more well-designed studies are needed to explore the possible cognitive benefits of different therapeutic options in patients with AF.

Anticoagulant use in atrial fibrillation and risk of dementia: review of contemporary knowledge

INTRODUCTION

Atrial fibrillation (AF) is strongly associated with dementia, including idiopathic dementias such as Alzheimer's disease. The relative risk of dementia is highest in AF patients 70 years and younger, and the burden of exposure to arrhythmia appears to underlie part of the risk. Areas covered: Anticoagulation choices and approach influence dementia risk. In warfarin patients, inadequate time spent in therapeutic range is highly associated with the increased dementia risk long-term. This risk is further accentuated with frequent over anticoagulation in patients also receiving aspirin. Direct oral anticoagulant therapies in early observational studies show that there is potential for improving long-term risk of dementia when compared to warfarin, although prospective trials are needed. AF and dementia are end manifestations of systemic disease; a systemic approach is needed with early treatment of shared risk factors to prevent disease presentation altogether. Expert commentary: In this review, we will bring together available data with regards to the link between anticoagulant use for AF and dementia. Anticoagulation initiation timing, use, and efficacy remain critical risk factors for dementia in AF patients and consequently provide opportunities to decrease risk.

Alteration of cerebrovascular haemodynamic patterns due to atrial fibrillation: an in silico investigation

There has recently been growing evidence that atrial fibrillation (AF), the most common cardiac arrhythmia, is independently associated with the risk of dementia. This represents a very recent frontier with high social impact for the number of individuals involved and for the expected increase in AF incidence in the next 40 years. Although a number of potential haemodynamic processes, such as microembolisms, altered cerebral blood flow, hypoperfusion and microbleeds, arise as connecting links between the two pathologies, the causal mechanisms are far from clear. An in silico approach is proposed that combines in sequence two lumped-parameter schemes, for the cardiovascular system and the cerebral circulation. The systemic arterial pressure is obtained from the cardiovascular system and used as the input for the cerebral circulation, with the aim of studying the role of AF on the cerebral haemodynamics with respect to normal sinus rhythm (NSR), over a 5000 beat recording. In particular, the alteration of the haemodynamic (pressure and flow rate) patterns in the microcirculation during AF is analysed by means of different statistical tools, from correlation coefficients to autocorrelation functions, crossing times, extreme values analysis and multivariate linear regression models. A remarkable signal alteration, such as a reduction in signal correlation (NSR, about 3 s; AF, less than 1 s) and increased probability (up to three to four times higher in AF than in NSR) of extreme value events, emerges for the peripheral brain circulation. The described scenario offers a number of plausible cause-effect mechanisms that might explain the occurrence of critical events and the haemodynamic links relating to AF and dementia.

Correlates of Dementia and Mild Cognitive Impairment in Patients With Atrial Fibrillation: The Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS)

BACKGROUND

Atrial fibrillation (AF) has been associated with faster cognitive decline and increased dementia risk. Factors associated with dementia in patients with AF have been seldom studied.

METHODS AND RESULTS

We studied 6432 individuals from the ARIC-NCS (Atherosclerosis Risk in Communities Neurocognitive Study). In 2011 to 2013, participants underwent a physical exam, echocardiography, detailed cognitive assessments, and a subset, brain magnetic resonance imaging. Dementia and mild cognitive impairment (MCI), as well as etiology of MCI/dementia, Alzheimer's disease-related or vascular, were adjudicated by an expert panel. AF was defined by study ECGs and past hospitalizations. We used logistic regression to estimate odds ratios and 95% CI of MCI/dementia by AF status and to assess cross-sectional correlates of MCI/dementia in patients with AF. Among 6432 participants, 611 (9.5%) had prevalent AF. AF was associated with increased odds of dementia and MCI (odds ratio, 95% CI, 2.25, 1.64-3.10, and 1.28, 1.04-1.56, respectively). Prevalence of Alzheimer's disease-related MCI/dementia and vascular MCI/dementia were higher in participants with AF than without AF (odds ratio, 95% CI, 1.29, 1.04-1.61, and 1.50, 0.99-2.25, respectively). In multivariable analyses, older age, lower body mass index, diabetes mellitus, stroke, and APOE genotype were associated with dementia prevalence in participants with AF. In models evaluating MCI/dementia subtypes, diabetes mellitus was associated with Alzheimer's disease-related MCI/dementia, whereas male sex and stroke were risk factors for vascular MCI/dementia.

CONCLUSIONS

In a large, community-based study, AF was associated with higher prevalence of MCI and dementia. Controlling cardiometabolic risk factors is a potential target for prevention of adverse cognitive outcomes in AF patients.

Atrial Fibrillation, Cognitive Decline And Dementia

Atrial fibrillation (AF) is a common cardiac arrhythmia. Growing evidence supports a role for AF as a risk factor for cognitive decline and dementia. In this review, we summarize epidemiologic observations linking AF with cognitive outcomes, describe potential mechanisms, and explore the impact of AF treatments on cognitive decline and dementia. Community-based, observational studies show a consistent higher rate of cognitive decline and risk of dementia in persons with AF. These associations are partly due to the increased risk of clinical stroke in AF, but other mechanisms, including incidence of silent cerebral infarcts, microbleeds, and cerebral hypoperfusion, are likely additional contributors. Adequate oral anticoagulation and improved management of the overall cardiovascular risk profile in persons with AF offer the promise of reducing the impact of AF on cognitive decline and dementia.