Exploring Associations Between Cardiac Structure and Retinal Vascular Geometry

Abstract

Background Retinal arteriolar narrowing and venular widening has been widely suggested to be associated with subclinical changes in cardiac structure. The novel retinal vascular geometric indices might reflect more comprehensive information on microvasculature other than vascular caliber alone. However, the association between suboptimal retinal vascular geometry and cardiac structural alteration has not been studied. Methods and Results We recruited 50 participants without cardiovascular disease from the Cardiac Aging Study conducted between 2014 and 2016. We performed transthoracic echocardiography imaging to measure cardiac structure indices such as left ventricular internal diameter end diastole index, left ventricular internal diameter end systole index, left ventricular mass index, and left atrial volume index, and retinal imaging to measure retinal vascular geometric indices including branching angle, curvature tortuosity, and fractal dimension. We applied multiple linear regressions to examine associations between indices of cardiac structure and retinal vascular geometry, adjusting for age, sex, body mass index, mean blood pressure, and comorbidity. The average age of all participants was 62.54 years old and slightly more than half were male (27; 54%). Each unit increase in a set of cardiac structure indices was associated with larger retinal arteriolar branching angle (β and 95% CI: for left ventricular internal diameter end systole index, 26.93°; 6.00-47.86; for left ventricular internal diameter end diastole index, 17.86°; 1.61-34.11; for left ventricular mass index, 0.39°; 0.10-0.67; for left atrial volume index, 0.91°; 0.24-1.58). Conclusions Adverse retinal arteriolar geometric morphology mirrored suboptimal cardiac structural alteration.

Keywords: cardiac structure; heart; retina; retinal microvasculature; retinal vascular geometry.

Figure 1

Singapore I Vessel Assessment grading platform for all retinal vascular parameters. The far left retinal fundus photograph is generated from a computer‐assisted program which is to assess retinal vascular parameters. All retinal arterioles and venules larger than 25 μm are marked and assessed within zone C that is within 0.5 to 2.0 optic disc diameter away from the margin of optic disc (highlighted in yellow). Retinal vascular caliber (A), retinal vascular tortuosity (B), retinal vascular branching angle (C), and retinal vascular fractal dimension (D) are shown, accordingly.