Retinal Vascular Geometry and the Prevalence of Atrial Fibrillation and Heart Failure in a Clinic-Based Sample

Abstract

Background: We aimed to examine the cross-sectional association between a range of retinal vascular geometric variables and the prevalence of atrial fibrillation (AF) and heart failure.

Methods: The Australian Heart Eye Study (AHES) surveyed 1,680 participants presenting to a tertiary referral hospital for the evaluation of potential coronary artery disease by coronary angiography. Retinal vascular geometric variables (tortuosity, branching, and fractal dimension) were measured from retinal photographs using a computer-assisted program (Singapore I Vessel Assessment). Atrial fibrillation was determined based on a combination of: self-reported history of AF; self-reported use of rate-control and anti-arrhythmic medications; and/or screening electrocardiogram. Self-reported echocardiography-confirmed heart failure was also documented.

Results: A total of 1,169 participants had complete information on retinal vascular geometric variables and AF and of these 104 (8.9%) had AF. Participants in the second tertile of fractal dimension (D_f) compared to those in the highest tertile (reference group), had 92% increased likelihood of having AF after multivariable adjustment. A threshold effect for D_f was identified, and participants below versus those above a D_f threshold value of 1.472, had greater odds of having AF: multivariable-adjusted OR 1.85 (95% CI 1.03-3.31). Measures of retinal tortuosity and branching were not associated with AF. Retinal vascular geometric variables were also not associated with prevalence of heart failure.

Conclusions: A sparser retinal microvascular network (lower D_f) was independently associated with greater likelihood of AF. Further studies are needed to investigate whether temporal changes to the retinal vascular geometry are predictive of AF in the longer term.

Keywords: Atrial fibrillation; Fractal dimension; Heart failure; Retinal vascular geometry.