Quantitative Optical Coherence Tomography Angiography Biomarkers in a Treat-and-Extend Dosing Regimen in Neovascular Age-Related Macular Degeneration: A 24-Months Follow-up Study

Abstract

Purpose : The role of optical coherence tomography angiography (OCT-A) in the follow-up of patients with exudative neovascular age-related macular degeneration (enAMD) has not been clearly clarified. Quantitative OCT-A parameters used to describe macular neovascularization (MNV) may be biomarkers that help predict anti-VEGF treatment burden and functional response. We performed an observational and prospective study to evaluate the association between quantitative OCT-A parameters and clinical outcomes over a 24-month follow-up interval.

Methods : Patients with enAMD were treated using a treat-and extend regimen following a loading dose of three anti-VEGF injections (IVI). Swept-source OCT-A was performed at baseline, after the loading dose and at 12 and 24 months. A quantitative analysis was performed for fractal dimension (FD), lacunarity index (LAC), blood flow surface area (SA), and vessel density (VD). Good functional response was defined as a final BCVA superior to/or within 5 letters of the 12th month visit. High treatment burden was defined as having at least 5 IVI in the second 12 months. Associations between quantitative biomarkers, functional outcomes and treatment burden at 24 months of follow-up were assessed. Statistical significance was defined as p-value < 0.05.

Results : Sixty-two eyes of 62 patients with enAMD were enrolled, 50 of whom (81%) completed the 24-month protocol. The median BCVA was 63 ETDR letters (21) at baseline, 74(25) at 12 months and 72 (28) at 24 months. 15 patients (30%) were classified as good functional responders. The median number of injections in the second year was 6 (2), with 40 patients (82%) classified as “high treatment burden”. A lower FD at the 12th month-visit was associated with a good functional response (p=0.008, area under the curve (AUC) = 0.74). Low treatment burden was associated with lower SA at the 12-month visit (p=0.013, AUC = 0.76).

Conclusions : FD and SA were two quantitative parameters of MNV blood flow derived from OCT-A that were associated with clinical outcomes whilst LAC and VD were not. The 12-month visit evaluation may give insights regarding the functional outcome and treatment burden for the following year, corroborating the hypothesis that OCT-A may play a role in a comprehensive enAMD follow-up.

This is a 2021 ARVO Annual Meeting abstract.