Background: Atrial fibrillation (AF) is an important risk factor for ischemic strokes and cognitive impairment. However, the association between AF and post‐stroke cognitive impairment (PSCI), along with any mediating factors, is unclear. We investigated the effects of AF, along with other risk factors, on PSCI in terms of global impairments and cognitive subdomains.
Methods: Cross‐sectional database of 445 subjects with mild ischemic stroke and no prestroke cognitive decline were assessed 3–6 months post‐stroke for cognitive deficits via neuropsychological assessment. MRIs were reviewed by trained raters for acute infarct characteristics, global cortical atrophy (GCA), white matter hyperintensities (WMH), cerebral microbleeds, and intracranial stenosis. Logistic regression analysis was used to identify factors independently associated with PSCI. In order to study cognitive trends, subjects were also categorized into four conditions according to presence or absence of AF or large cortical infarcts (LCIs): Nil, AF Only, LCI Only, and AF+LCI.
Results: 82 (18.4%) subjects had AF. 85.4% of AF subjects and 57.3% of subjects with no AF had PSCI. AF subjects had more risk factors and greater burden of acute and chronic ischemia, scored worse in neuropsychological tasks associated with global cognition [Mini‐Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA)], episodic memory (10‐word immediate and delayed recall), and executive function [Frontal Assessment Battery (FAB) and animal naming fluency].[Table 1] Having AF was associated with an odds ratio of 2.17 for developing PSCI (95% CI: 1.03 − 4.58; p=0.041)] after adjusting for age, education, hypertension, large cortical and non‐cortical infarcts, WMH, and intracranial stenosis. When comparing subjects in the four conditions, AF+LCI subjects scored worse in MMSE, MoCA, and FAB than LCI Only and Nil subjects. AF Only subjects scored worse in 10‐word immediate recall than Nil subjects. [Figure 1].
Conclusions: AF is a significant risk factor for PSCI, and this effect is independent of acute infarct characteristics. The profile of PSCI in subjects with AF is characterized by deficits in episodic memory and executive function. Pathophysiological links between AF and PSCI, likely includes mechanisms other than infarcts such as cerebral hypoperfusion and neuroinflammation, may help to explain the observed impairments in these specific cognitive subdomains.