Retinal microvascular structure and function in patients with risk factors of atherosclerosis and coronary artery disease

OBJECTIVE: Retinal microvascular signs are markers of cardiovascular disease risk. There are limited data, on relationships between retinal microvascular signs and retinal microvascular endothelial function. We sought to determine the relationship of retinal vascular signs with retinal microvascular endothelial function in patients with or at high risk of coronary artery disease. METHODS: Participants with atherosclerosis risk factors and coronary disease (n=258; mean age 57±11 years) were recruited to have static and dynamic retinal vascular assessment. Retinal arteriolar dilatation in response to flicker light (FI-RAD) was measured using the Digital Vessel Analyser and expressed as percentage increase over baseline diameter. Static retinal photographs were acquired utilising a digital fundus camera for measurement of central retinal artery and vein equivalent (CRAE and CRVE), arteriovenous nicking (AVN) and focal arteriolar narrowing (FAN). RESULTS: Intra-class correlation coefficient was 0.82 for flicker-light induced retinal arteriolar dilatation. There were modest associations in retinal vascular measurements between eyes. For each 10 μm decrease in retinal arteriolar diameter, the absolute increase in FI-RAD was 0.28% (95% CI 0.11, 0.45; p=0.002) independent of age, gender and atherosclerosis risk factors. AVN and FAN were associated with attenuated FI-RAD (β=-0.67%; 95% CI -1.20, -0.15; p=0.012) and (β=-0.83%; 95% CI -1.44, -0.23; p=0.007) respectively after adjustment for age and gender. CONCLUSION: Assessment of retinal microvascular endothelial function is reproducible and correlated with retinal microvascular structure and signs, independent of atherosclerosis risk factors. Assessment of retinal vascular structure and function may provide insights into atherosclerotic disease