Atrial Fibrillation, Stroke, and Silent Cerebrovascular Disease: A Population-Based MRI Study

Abstract

Background and Objectives:Atrial fibrillation (AF) has been associated with cognitive decline and dementia. However, the mechanisms behind these associations are not clear. Examination of cerebrovascular pathology on MRI may shed light on how AF affects the brain. This study aimed to determine whether AF is associated with a broad range of cerebrovascular diseases, beyond the well-known association with symptomatic stroke, including silent infarcts and markers of small vessel disease, e.g. cerebral microbleeds (CMBs), white matter hyperintensities (WMHs), and lacunes, in a population-based sample of 70-year-olds.Methods:Data were obtained from the Gothenburg H70 Birth Cohort Studies, where individuals are invited based on birth-date. This study has a cross-sectional design and includes individuals born 1944 who underwent structural brain MRI in 2014-17. AF diagnoses were based on self-report, EKG, and register data. Symptomatic stroke was based on self-report, proxy-interviews, and register data. Brain infarcts and CMBs were assessed by a radiologist. WMH volumes were measured on FLAIR images using the Lesion Segmentation Tool. Multivariate logistic regression was used to study the association between AF and infarcts/CMBs, and multivariate linear regression was used to study the association between AF and WMHs.Results:A total of 776 individuals were included and 65 (8.4%) had AF. AF was associated with symptomatic stroke (OR 4.5, 95% CI 2.1-9.5), and MRI findings of large infarcts (OR 5.0, 95% CI 1.5-15.9), lacunes (OR 2.7, 95% CI 1.2-5.6), and silent brain infarcts (OR 3.5; 95% CI 1.6-7.4). Among those with symptomatic stroke, individuals with AF had larger WMH volumes (0.0137 ml/total intracranial volume (TIV), 95% CI 0.0074-0.0252) compared to those without AF (0.0043 ml/TIV, 95% CI 0.0029-0.0064). There was no association between AF and WMH volumes among those without symptomatic stroke. In addition, AF was associated to CMBs in the frontal lobe.Discussion:AF was associated with broad range of cerebrovascular pathologies. Further research is needed to establish whether cerebrovascular MRI markers can be added to current treatment guidelines to further personalise anticoagulant treatment in AF patients and to further characterize the pathogenetic processes underlying the associations between AF and cerebrovascular diseases, as well as dementia.