Peripheral vascular disease is associated with abnormal arteriolar diameter relationships at bifurcations in the human retina

Abstract

Arterial diameters at branch points are believed to conform to design principles that optimize circulatory efficiency and maintain constant shear stress across arterial networks. The objective of this study was to examine whether optimality at bifurcations is affected in individuals with atherosclerosis. Retinal images were analysed in normotensive men with abnormal ankle brachial index (n=13) and healthy controls (n=8), matched for age and clinic blood pressure. Compared with controls, men with peripheral vascular disease had adverse metabolic profiles (relative insulin resistance and greater total cholesterol levels). In healthy men, retinal arterial diameters at bifurcations conformed to predicted optimal values but in men with peripheral vascular disease, junction exponents deviated significantly from the optimum. Retinal arteriolar bifurcation angles did not differ significantly between the groups. Atherosclerosis is associated with abnormalities in the arteriolar network of the retina. In view of the importance of the endothelium in maintaining network co-ordination of branch diameters this is suggestive of a generalized abnormality of endothelial function in atherosclerosis.

Ocular Biomarkers for Early Detection of Alzheimer's Disease

“…Vascular topography, including the angles at which blood vessels bifurcate and the relationship between the widths of parent to daughter blood vessels at vascular junctions is optimized in healthy subjects in order to minimize shear stress across a vascular network [149][150]. Variations from the optimal geometrical topography are known to occur in particular vascular conditions [151][152]. Similar variations may occur in AD due to the disease's vascular component and hence are worthy of being explored with retinal photography.…”

Manual measurement of retinal bifurcation features

“…In our study, the mean is 1.27, the standard deviation is 0.22, and the range is [0.66 1.86]. The optimality parameter (ρ) [19] which measures deviation of junction exponents from the optimal value of 3, is calculated as:…”

Ethnic differences in retinal microvascular structure

“…We have previously demonstrated associations between retinal arteriolar narrowing and hypertension [4] and between arteriolar bifurcation optimality and lower-limb atherosclerosis [5] and ischaemic heart disease mortality [6].…”