P2.01 HIGH RESOLUTION IMAGING OF SMALL ARTERIES IN THE HUMAN RETINA DURING HYPERTENSIVE RETINOPATHY

Abstract

Objective: Morphological changes affecting small arteries are recognized surrogates of end-organ damage due to aging and/or hypertension. However, the corresponding structural modifications of the wall of microvessels are poorly known. Here, using adaptive optics (AO) infrared imaging, we analyzed the vascular microstructures in subjects with various degree of hypertensive retinopathy. Methods: The wall-to-lumen ratio (WLR) of the superotemporal artery was measured in 40 normotensive or treatment-naïve hypertensive subjects using a semi-automated procedure. Areas of focal vascular damage were also analyzed. Results: Intra- and interobserver reproducibility was high (ICC over 0.8 for all parameters measured). In treatment-naïve subjects, the WLR of the superotemporal artery (mean ± SD 0.31 ± 0.08) was independently correlated with diastolic blood pressure (p<0.01), and lumen diameter (p<0.01). Neither focal arteriolar narrowing (FANs; (n=10) or arteriovenous nicking (AVNs; n=12) showed parietal thickening. Instead, at sites of FANs, a reduction of the outer diameter was consistently found, while at sites of AVNs venous narrowing and retinal opacification were observed distal to the arteriovenous interface. In addition, in four cases of AVNs the absence of arteriovenous contact could be unequivocally demonstrated. Interpretation: AO imaging allows a reproducible analysis of the lumen diameter and parietal thickness of retinal vessels. Parietal thickness of retinal arterioles was correlated to blood pressure, but not focal lesions which appeared to involve either focal vasoconstriction and/or periarteriolar changes. AO imaging may thus contribute to a better understanding of end-organ damage linked to microvasculopathy.