Volumetric characteristics quantification of choroidal neovascularization secondary to exudative age-related macular degeneration in swept source OCT angiographyduring the monthly loading dose of anti-VEGF therapy.

Abstract

Purpose : To use swept-source optical coherence tomography angiography (SS-OCTA) to monitor the 3 dimensional structural modification and short-term blood flow changes of choroidal neovascularization (CNV)in treatment-naïve eyes with age-related macular degeneration during the monthly loading dose of anti-VEGF therapy.

Methods : 5 treatment-naive patients were evaluatedevery week with SS-OCTA during anti-VEGF loading dose. Macular spectral-domain OCT (SD-OCT,Heidelberg Engineering; Vista, CA) were performed at each visit and retinal SS-OCTA volumes of either a 3x3mm or a 6x6mm field of view were collected using a PLEX® Elite 9000 with AngioPlex OCT Angiography (ZEISS, Dublin, CA). The CNV total volume, area, vessel perfusion (total area of perfused vasculature), vessel density (total length of perfused vasculature)and invasiveness (intrusion within the retina) were measured and compared to exudative signs seen on SD-OCT. CNV invasiveness was characterized by the “invasiveness volume rate” (ratio between the CNV volume and the total retina volume), “CNV maximum height”, “maximum height rate” (maximum value of theratio between CNV thickness and retina thickness)and “mean height rate”(average value of the ratio between CNV thickness and retina thickness).

Results : Preliminary results of the 3 first patients showed rapid decrease of the mean CNV volume (30%) and the mean CNV area (24%) one week after anti-VEGF therapy, followed from the 2^ndweek by a gradual increase until a return to their initial valueat the next intravitreal injection. All invasiveness parameters showed a decrease from the injection then remained stable until return to the initial state one month after.Conversely vessel density and perfusion did not show a significant difference during treatment. On SD-OCT, exudative signs reappeared from the 3^rdweek after anti-VEGF treatment.

Conclusions : The close follow-up of CNV on OCTA reveals a very rapid decrease in CNV volume and CNV area after anti-VEGF intravitreal injection within treatment cycles.
Quantitative changes, taking into account the whole volume of the CNV, appear before the exudative signs on SD-OCT suggesting a prediction of CNV activity and the possibility to better optimize the anti-angiogenic treatment.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.