Epidemiology of cerebral microbleeds and risk of adverse outcomes in atrial fibrillation: a systematic review and meta-analysis

Association of Atrial Fibrillation and Cognitive Dysfunction: A Comprehensive Narrative Review of Current Understanding and Recent Updates

Atrial fibrillation (AF) is the most common sustained arrhythmia in adults. The prevalence of both AF and dementia is steadily rising and is expected to rise further in the coming decades. There is increasing evidence to suggest an association between AF and various degrees of cognitive dysfunction, from mild cognitive impairment to severe dementia. In this review, we aimed to discuss the epidemiological aspects, pathophysiological mechanisms, role of neuroimaging, impact of treatment modalities, and clinical and socioeconomic impact of this association. Numerous observational studies and meta-analyses have revealed this association to exist in AF patients with and without a history of stroke, and the association also persists after adjusting for shared risk factors such as hypertension and diabetes mellitus. Various pathophysiological mechanisms have been proposed for this association, including silent cerebral infarcts, cerebral microbleeds, cerebral hypoperfusion, inflammation, and atherosclerosis. While neuroimaging findings have been utilized to suggest some of these pathophysiological mechanisms, more studies are needed to further elucidate this and to determine the potential role of neuroimaging in altering anticoagulation and other treatment decisions. Anticoagulants have shown effectiveness in reducing the rate of cognitive decline in AF patients; however, their role in low-risk AF patients remains under investigation. Even though AF patients receiving catheter ablation may have post-operative cognitive dysfunction in the short term, long-term follow-up studies have shown an improvement in cognitive function following ablation. Cognitive decline in AF patients often occurs with greater functional decline and other psychosocial impairments such as depression and anxiety and future research on this association must incorporate aspects of social determinants of health and associated outcomes.

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.

Risk of intracranial hemorrhage in patients using anticoagulant therapy for atrial fibrillation after cerebral microbleeds combined with acute ischemic stroke: a meta-analysis

Objective

To evaluate intracerebral hemorrhage (ICH) risk in patients with ischemic stroke (IS) and cerebral microbleeds (CMBs) undergoing anticoagulation therapy for non-valvular atrial fibrillation (AF).

Methods

We conducted a comprehensive search across multiple databases, including Embase, PubMed, Cochrane, UpToDate, Scopus, WOS, and SinoMed. The search covered observational literature published from each database inception until February 1, 2023. We analyzed the prevalence of CMBs during the follow-up period, compared future ICH risk between patients with and without baseline CMBs (CMBs presence/absence, ≧5 CMBs), and examined factors influencing ICH occurrence in patients with CMBs. Also studied recurrent stroke during anticoagulation therapy, the risk of future ICH when white matter hyperintensity (WMH) and CMBs coexist, and the effects of anticoagulants vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs) on future ICH.

Results

We included 7 articles involving 5,134 participants. The incidence of CMBs was 24%; baseline CMBs were associated with an increased ICH risk compared to patients without CMBs. ICH-risk was more significant in patients with baseline ≥5 CMBs. After anticoagulant therapy, ICH risk was higher than that of recurrent IS. The risk of future ICH was significantly increased with anticoagulant VKAs compared with NOAC.

Conclusion

Anticoagulant therapy for ischemic stroke patients with non-valvular AF and CMBs increases future ICH risk. Discontinuing anticoagulation due to ICH risk should be avoided. NOACs are safe and effective for patients with CMBs and IS.