Evaluation of microvascular density and retinal vessel diameter in gestational and type 2 diabetes using swept-source OCT-A technology

Abstract

To assess foveal and parafoveal retinal and choroidal microvascular changes using optical coherence tomography angiography (OCTA) and changes in retinal vessel caliber in pregnant women with gestational diabetes mellitus (GDM), non-pregnant female patients with type 2 diabetes mellitus (DM2), and healthy pregnant female subjects. The study was conducted cross-sectionally and composed of three age-matched groups: 32 near-term pregnant women with GDM (GDM group), 32 non-pregnant female patients with a recent diagnosis of DM2 (DM2 group), and 32 healthy near-term pregnant female subjects. Vessel density (VD) and vessel diameter were the main outcomes. Detailed ophthalmic examinations were performed for each participant, including swept-sourceOCTA measurements consisting of superficial, deep, outer retinal and choroidal vessel density. The average VD values in the central fovea of the superficial and deep retina were significantly lower in the GDM group (P=0.001 for both, between the three groups), whereas the mean VD in the parafoveal nasal sector of the deep retina was significantly lower in the DM2 group (P=0.008, between the three groups). There were no significant differences in the foveal or parafoveal VD measurements of the outer retina and choriocapillaris (P>0.05 for all). There were statistically significant differences in the retinal venous diameter and arterial vein ratio in the GDM and DM2 groups compared to the control group (P=0.001 for all). The microvascular density changes seen on OCTA images of pregnant women with GDM are remarkable. These changes in retinal vessels appeared to occur rapidly after the onset of the metabolic impairment or might be the reflection of previous insulin resistance as well, as in recent diabetes. Our results also suggest that these changes may be more significant in a GDM pregnant woman than in a pregnant, established diabetic patient.