Abnormalities of Retinal Microvascular Structure and Risk of Mortality From Ischemic Heart Disease and Stroke

Abstract

Abstract-Abnormalities of the retinal microcirculation are found in hypertension and diabetes and predict cardiovascular mortality. This study examined the relationship between abnormalities of the retinal microvasculature and death from ischemic heart disease (IHD) and stroke. A population-based, nested case-control study was undertaken within the Beaver Dam Eye Study. Subjects (43 to 74 years) who died of IHD (nϭ126) or stroke (nϭ28) over a 10-year period were age and gender matched with controls subjects (nϭ528; case:control matching, Ϸ1:4). Retinal photographs of cases and controls were digitized and analyzed using a computer-based technique. Increased risk of IHD death was associated with a suboptimal relationship of arteriolar diameters at bifurcation (Pϭ0.02 unadjusted) and decreased retinal arteriolar tortuosity (Pϭ0.011 unadjusted). These associations remained significant after adjustment for age, sex, past history of cardiovascular disease, and other known cardiovascular risk factors. Increased arteriolar length:diameter ratio, a measure of generalized arteriolar narrowing, was associated with increased stroke mortality (Pϭ0.02 unadjusted). This association was independent of age and gender but was attenuated by adjustment for systolic blood pressure (Pϭ0.15). Other quantitative measures of the retinal microvascular network (eg, venular tortuosity and arteriolar and venular bifurcation angle) were not associated with death from IHD or stroke. Retinal microvascular abnormalities are predictive of death from IHD and stroke. A detailed assessment of the retinal microvascular network from digitized photographs may be useful in the noninvasive assessment of target organ damage and cardiovascular risk.

Retinal vascular tortuosity in persons with diabetes and diabetic retinopathy

“…There have been studies suggesting that increased vessel tortuosity is related to diabetes-driven haemodynamic changes such as disturbed blood flow [11,22], tissue hypoxia [13], endothelial dysfunction [12,23], and increased levels of VEGF [15,16,24]. In persons with diabetes, hyperglycaemia-mediated hypoperfusion can initiate blood flow disturbance together with the loss of endothelium cells and pericytes of the vessel wall, leading to the loss of autoregulatory function of the vessels including its compensatory mechanisms for the fluctuating hydrostatic pressure [25].…”

How does hypertension affect your eyes?

“…35,36 Several studies using novel retinal vascular features such as branching angles, bifurcation, fractal dimension, tortuosity, vascular length-to-diameter ratio and wall-to-lumen ratio have shown that these features may also be related to hypertension and may provide additional information in predicting cardiovascular diseases. 35,[37][38][39][40][41] More specifically, increased curvature as reflected by a greater retinal venular tortuosity and wider retinal venular caliber have been linked with elevated blood pressure. 35,42 Furthermore, smaller fractal dimension and smaller arteriolar branching asymmetry ratio have been shown to be associated with uncontrolled and untreated hypertension.…”

Retinal Vascular Changes in Pre-Diabetes and Prehypertension

“…Different analytical methods have hampered the comparison of results between studies, and application-common methods in different studies will allow data pooling to generate more valid risk estimates. Additionally, the role of novel measures of retinal vascular structure (99,103,(111)(112)(113) in predicting diseases remains to be determined.…”