Longitudinal changes in retinal microvascular measured by Adaptive Optics

BackgroundAdaptive Optics retinal imaging (AO) enables high-resolution visualization of the retinal microvasculature providing insights into systemic vascular health. Currently, no studies exist describing changes in wall-to-lumen ratio (WLR) during pregnancy, neither during the physiological course of pregnancy nor in pregnancy-associated complications. Methods and MaterialThis single-centre, prospective study at the Leipzig University Hospital, Germany, examines longitudinal changes in retinal microvasculature by employing AO (rtx1e, Imagine Eyes, Orsay, France) to calculate the WLR of an arteriole within few seconds. The study examined a well-phenotyped cohort of 495 primarily Caucasian healthy pregnant women, with 584 measurements taken from the first to the third trimester. The WLR was automatically determined using the nnUNet deep learning model. ResultsAs demonstrated in the linear mixed-effects model, gestational age exhibited the most significant effect on WLR (p < 0.001). Changes in WLR were also significantly associated with maternal age (p = 0.04) and mean arterial blood pressure (p < 0.001). Primiparous women had significantly lower WLRs at baseline (p < 0.01) and exhibited significantly steeper increases in WLR throughout gestation (p = 0.01) than nulliparous women. ConclusionWe identify WLR as a sensitive marker for imaging microvascular remodeling, serving as an indicator of adaptation to physiological pregnancy. Normal pregnancy is associated with an instant change of the retinal microvasculature indicated by an increase of WLR. Further studies are required to investigate the postpartum course of WLR and establish whether these changes are reversible.