The OCTAF study is a monocentric, cross-sectional pilot study designed to investigate the relationship between retinal microvascular biomarkers and cognitive impairment in patients with atrial fibrillation (AF). Atrial fibrillation is a highly prevalent cardiac arrhythmia associated not only with stroke and cardiovascular complications but also with an increased risk of cognitive decline, even in the absence of overt cerebrovascular events. Current approaches to detect cognitive impairment are often time-consuming and resource-intensive, highlighting the need for simple, non-invasive screening tools. The retina, often described as a "window to the brain," provides a unique opportunity to assess microvascular health, and Optical Coherence Tomography Angiography (OCT-A) allows detailed, non-invasive visualization of retinal blood flow and structure.
In this study, 40 patients with AF aged 40 years or older will be recruited at UZ Brussels and stratified according to cognitive status using the Montreal Cognitive Assessment (MoCA), with a score below 26 indicating cognitive impairment. Each participant will undergo a standardized evaluation including a questionnaire capturing demographic characteristics and vascular risk factors, a MoCA cognitive test, and OCT-A imaging of the retina and optic nerve head. The imaging will focus on quantifying vessel density in different retinal layers, including the superficial and deep capillary plexuses and radial peripapillary capillaries, as well as measuring the foveal avascular zone area.
The primary objective is to compare these OCT-A parameters between AF patients with and without cognitive impairment. Statistical analyses will be exploratory and performed using regression models to account for potential confounders such as age and cardiovascular risk factors. As a pilot study, the aim is not to establish definitive causal relationships but to assess feasibility, characterize variability, and generate preliminary data that may guide future larger-scale studies. The study is expected to run from late 2025 to September 2026 and will adhere to ethical standards and Good Clinical Practice guidelines. Ultimately, the study seeks to determine whether retinal imaging could serve as a practical and non-invasive tool for early detection of cognitive decline in patients with atrial fibrillation.