Retinal vascular study using OCTA In subjects at high genetic risk of developing Alzheimer's disease

Purpose: To analyse morphological changes in retinal vascular network in 103 subjects with a high genetic risk of developing Alzheimer's Disease (AD) ((family history of AD(FH) and ApoE ɛ4 characterization (ApoE ɛ4)). Methods: OCTA images were analysed with two imaging software programs: AngioTool and Erlangen‐Angio‐Tool (EA‐Tool). Participating subjects were classified according to HF into HF− or HF+ and ApoE ɛ4 characterization into ApoE ɛ4− or ApoE ɛ4+. Vascular density was analysed considering two vascular risk factors: hypercholesterolemia (HCL) and arterial hypertension (HBP). Results: Taking account FH and allelic characterization, vascular changes were observed mainly in the peripapillary zone. In this zone, Angio‐Tool showed in the FH+ ApoE ɛ4− group a statistically significant higher of vessels surface area percentage compared to the FH+ ApoE ɛ4+ group. EA‐Tool showed in the C3 annulus in the FH+ ApoE ɛ4+ group, statistically significant higher vascular densities compared to the groups: (i) FH− ApoE ɛ4− in sectors H3, H4, H10, and H11; and (ii) FH+ ApoE ɛ4− in sectors H4, and H12. In participants with vascular risk factors (LCH and BPH), statistically significant changes were found especially with EA‐Tool, both in the macular area, mainly in the deep plexus, and in the peripapillary area. Conclusions: In subjects with two genetic risk factors for the development of AD, OCTA is able to show an apparent increase in vascular density in some sectors of the retina, probably caused by the opening of arteriovenous shunts. This finding is one of the first vascular changes detectable by OCTA in this type of high‐risk subjects for the development of AD. This constitutes a promising biomarker to monitor the progression of the disease.