Assessing the Correlation Between Retinal Arteriolar Bifurcation Parameters and Coronary Atherosclerosis

Abstract

Introduction: The aim of this study was to examine the relationship between the morphological parameters of retinal arteriolar bifurcations and coronary artery disease (CAD).

Methods: In this cross-sectional observational study, fundus photography was conducted on 444 participants to capture retinal arteriolar bifurcations. A total of 731 fundus photographs yielded 9625 measurable bifurcations. Analyzed bifurcation parameters included the diameters of the parent vessel (d₀), the larger branch (d₁), and the smaller branch (d₂), as well as the angles (θ₁) and (θ₂) representing the orientation of each branch in relation to the parent vessel, respectively. Additionally, theoretical optimal angles ( ${\theta }_1^{\text{'}}$ ) and ( ${\theta }_2^{\text{'}}$ ), calculated from the measured parameters, provided a benchmark for ideal bifurcation geometry. The study assessed the variation in these parameters across different levels of coronary atherosclerosis severity.

Results: After adjusting for anatomical characteristics including the asymmetry ratio, area ratio, and distance to the optic disc, we observed that patients with severe coronary artery stenosis had significant deviations from the theoretical optimal bifurcation angles, with a decrease in ( ${\theta }_1^{\text{'}}$ ) and an increase in ( ${\theta }_2^{\text{'}}$ ) compared to those with moderate stenosis.

Conclusion: The findings suggest a clear alteration in retinal arteriolar bifurcation morphology among patients with severe CAD, which could potentially serve as an indicator of disease severity.

Keywords: Bifurcation; Coronary artery disease; Deep learning; Fundus image; Retinal arteriole.