Quantitative optical coherence tomography angiography biomarkers in a treat-and-extend dosing regimen in neovascular age-related macular degeneration

Purpose: To evaluate the association between quantitative optical coherence tomography angiography (OCT-A) parameters and clinical outcomes in treatment-naïve neovascular age-related macular degeneration (nAMD) patients treated with a treat-and-extend dosing regimen on a 12-month follow-up interval. Methods: Observational, prospective study of consecutive patients. The treatment protocol was based on a loading dose of three anti-vascular endothelial growth factor (VEGF) intravitreal injections (IVI) followed by a treat-and-extend regimen. Eyes were evaluated by swept-source OCT-A at baseline, 1 month after the loading dose and at 12 months. A quantitative analysis was issued for fractal dimension (FD), lacunarity index (LAC), blood flow surface area (SA), and vessel density (VD). An association of these parameters with the anatomic response and functional responses, and IVI number at 12 months of follow-up was assessed. A level of significance α = 0.05 was considered. Results: Sixty-four patients were included, 52 of whom (81%) completed the 12-month study protocol. The median number of injections at 12 months was 7 (P25-P75: 6-12). FD and SA were reduced 1 month after the loading dose of anti-VEGF (P < 0.001). The generalized linear models using baseline FD and baseline SA achieved the best performance in discriminating a lower treatment burden (area under the curve [AUC] = 0.78; 95% confidence interval [CI]: 0.64–0.91 and AUC = 0.76; 95% CI: 0.63–0.90, respectively). Conclusions: Baseline OCT-A may provide useful biomarkers for the treatment burden in nAMD. Translational Relevance: The application of fractal dimension and automatic blood flow area algorithms to OCT-A data can distinguish patients with distinct treatment burdens in the first year of nAMD.