Retinal vascular reactivity in type 1 diabetes patients without retinopathy using optical coherence tomography angiography

Abstract

Purpose : We hypothesize that patients with type 1 diabetes (T1D) may have abnormal retinal vascular responses before diabetic retinopathy (DR) is clinically evident. Optical coherence tomography angiography (OCTA) was used to dynamically assess the retinal microvasculature of diabetic patients with no clinically visible retinopathy.

Methods : Controlled non-randomized interventional study. The studied population included 48 eyes of 24 T1D patients and 24 demographically similar healthy volunteers. A commercial OCTA device (AngioVue®) was used and two tests were applied: (i) the hypoxia challenge test (HCT) and (ii) the handgrip test, in order to induce a vasodilatory or vasoconstrictive response, respectively. The HCT is a standardized test that creates a mild hypoxic environment equivalent to a flight cabin. The handgrip test (i.e. isometric exercise) induces a sympathetic autonomic response. Changes in the parafoveal superficial and deep capillary plexuses in both tests were compared in each group. Systemic cardiovascular responses were also comparatively evaluated.

Results : In the control cohort, the median parafoveal superficial and deep plexuses’ vessel density increased during hypoxia (F_1,23=15.69, p<0.001 and F_1,23=16.26, p<0.001, respectively). In the T1D group, this physiological response was not observed in neither the superficial, nor the deep retinal plexuses. Isometric exercise elicited a significant decrease in vessel density in both superficial and deep plexuses in the control group (F_1,23=27.37, p<0.0001 and F_1,23=27.90, p<0.0001, respectively). In the T1D group, this response was noted only in the deep plexus (F_1,23=11.04, p<0.01).

Conclusions : Our work suggests there is an early impairment of the physiologic retinal vascular response in patients with T1D without clinical diabetic retinopathy.

This is a 2021 ARVO Annual Meeting abstract.