Evaluation of OCTA Biomarkers May Better Inform nAMD Treatment

Praveen J. Patel, MD, MBBCHIR

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Macular neovascularization (MNV) biomarkers were detectable using optical coherence tomography angiography (OCTA) in patients with treated stable neovascular age-related macular degeneration (nAMD), suggesting the usefulness of the technology in confirming MNV stability.¹

The analysis from the Moorfields Eye Hospital reported other identified OCTA features including the development of a mature MNV phenotype, the presence of central feeder vessel, the absence of capillary fringe, and hyporeflective halo, as well as MNV blood flow, in patients with treated stable MNV.

“We suggest that these features are useful biomarkers to confirm MNV stability when used concurrently with conventional structural OCT assessment,” wrote the investigative team. “They could be used to help guide treatment decisions and plan appropriate treatment intervals for patients with nAMD.”

Led by Praveen J. Patel, MD, MBBCHIR, NIHR Biomedical Research Centre at Moorfields Eye Hospital, the study aimed to describe features of disease activity in patients with treated stable MNV in nAMD using OCTA. As OCTA can enable concurrent visualization of blood flow by repeated sequential segmental OCT cross-sectional imaging at the same anatomical location, it can be used to identify MNV in patients with nAMD. A better understanding of OCTA biomarkers of nAMD disease activity could help guide treatment regiments with anti-vascular endothelial growth factor agents, according to investigators.

The current study formed part of the single-center prospective, observational study Defining Disease Activity in Neovascular AMD with Optical Coherence Tomography imaging (DANA) study. Participants were eligible for DANA if they were more than 50 years old and were receiving aflibercept treatment for nAMD on a treat-and-extend regimen and had achieved a 12-week interval between injections.

Study subjects underwent spectral-domain OCT and OCTA imaging on Spectralis OCT, completed by a clinical-trials certified ophthalmic technicians. All OCT and OCTA images were evaluated for signs of nAMD disease activity by the Moorfields Eye Hospital Reading Center. The study included 32 eyes of 32 patients with treated stable nAMD who underwent study imaging between September 2019 and March 2020.

Data showed subjects had a mean visual acuity of 69.7 ETDRS letters and had undergone a mean of 16.4 intravitreal injection treatments at baseline. Investigators noted no macular hemorrhage was identified on slit-lamp biomicroscopy at the 12-week treatment visit.

The evaluation of SD-OCT images at the study location confirmed no significant image artifact preventing grading in any of the 32 SD-OCT macular scans and additionally confirmed that no SD-OCT images had signs of active nAMD. Evaluation of OCTA images confirmed that 31 of 32 images were gradable without significant imaging artifacts.

Results showed the mean OCTA lesion size was 3.6mm² ± 4.6 mm² and 27 eyes (87.1%) had detectable MNV blood flow. An analysis of MNV morphology confirmed MNV maturity in 29 (93.5%) of eyes, consisting of 10 non-specific, 10 tangled, and 3 deadtree phenotypes. Meanwhile, OCTA imaging analysis of qualitative features of disease activity included the presence of MNV peripheral halo (29, 93.5%), capillary fringe (1, 3.2%), and central feeder vessel (19, 61.3%).

As OCTA visualized blood was visible in most treated MNV, MNV may consist of persistent active vessels despite no ongoing subretinal or intraretinal fluid on structural OCT examination. Investigators noted the clinical significance of OCTA-visualized blood flow is thus unclear, suggesting the need for further investigation into how the pattern of blood flow affects the development of disease activity.

“Further evaluation of OCTA in nAMD is of course necessary but OCTA technology may allow for the ability to characterise the risk of disease reactivation particularly useful when planning long-term treatment strategies and clinical protocols,” investigators wrote.

References

1. Hanumunthadu, D., Saleh, A., Florea, D. et al. Biomarkers of macular neovascularisation activity using optical coherence tomography angiography in treated stable neovascular age related macular degeneration. BMC Ophthalmol 23, 68 (2023). https://doi.org/10.1186/s12886-022-02749-5