Impact of Anti-VEGF therapy on Swept Source OCTA measurements in Diabetic Retinopathy

Abstract

Purpose : To evaluate the utility of Swept-Source Optical Coherence Tomography Angiography (SS-OCTA) in non-invasively assessing change in perfusion and density after anti-VEGF therapy in diabetic retinopathy (DR) when compared to ultra-widefield Fluorescein Angiography (UWFA) leakage metrics.

Methods : This is a retrospective review of consecutive DR patients who had received repeated SS-OCTAs (Zeiss Plex Elite) and UWFAs (Optos California). 6mm x 6mm and 3mm x 3mm images of non-proliferative and proliferative DR eyes were analyzed. Both perfusion density (total area of perfused vasculature per unit area ranging from 0-1) as well as vessel density (total perfused vasculature per unit area) were obtained. UWFA metrics were quantified using a customized feature analysis platform that detected leakage indices automatically (3-disc diameter and 6-disc diameter areas of leakage centered on the macula). Statistical analysis was performed using MS-Excel.

Results : 20 eyes were included in the 6x6 SS-OCTA non-treatment group while 8 eyes were in the treatment group. Of these, 16 also had 3x3 SS-OCTA for the non-treatment group and 4 had treatment. UWFA analysis was available for 15 of the eyes without treatment and 6 of those with treatment. Average follow up was 12.1 months.

In the 3x3 non-treatment group there was significant reduction in superficial and deep perfusions and densities over time within the average field of view (p<.05). Superficial perfusion density averaged at 0.314 at baseline and decreased 12.1%. Deep perfusion density averaged 0.184 at baseline and reduced by 23.5%. No significant difference was seen in the treatment group (p>0.1). Similar associations were seen in the 6x6 SS-OCTA non-treatment (p<0.1) vs treatment groups (p>0.1).

Findings of UWFA showed similar trends, with leakage indices worsening in those not treated vs treated. 6-disc diameter macula centered leakage area showed an average baseline leakage of 1.8% that increased 50.7% in the non-treatment group (p=0.056) and had insignificant change in the treatment group p>0.1.

Conclusions : SS-OCTA and UWFA can quantify the impact of anti-vegf therapy in DR patients over time. Using both modalities, trends towards better perfusion metrics in those treated vs non treated were seen. Further larger investigations will verify whether SS-OCTA can quantify a difference from anti-VEGF treatment over time in DR patients.

This is a 2021 ARVO Annual Meeting abstract.