Author: Anthony Gigon (Switzerland)
Co-authors: Antonio Iskandar, Irmela Mantel
Purpose
Intravitreal injections (IVI) of anti-vascular endothelial growth factor (VEGF) agents is the cornerstone of management of neovascular Age-related Macular Degeneration (nAMD), dramatically improving its prognosis. Some cases remain incomplete responders despite maximal monthly injections. These cases are sometimes referred to as refractory. However, the short term response profile is poorly understood. The goal of the present study was to study their short term response in between monthly IVI and identify factors associated with the short term response profile.
Setting/Venue
Monocentric prospective study conducted in the tertiary referral center of Jules Gonin Eye Hospital, Lausanne, Switzerland.
Methods
Patients were prospectively selected from the regular AMD clinic. Patients with refractory nAMD were recruited, defined by the presence of intraretinal (IRF) and/or subretinal fluid (SRF) at monthly monitoring visits over at least 6 months, despite monthly IVI. Patients with confounding retinal diseases or poor image quality were excluded. A complete ophthalmic exam was performed at baseline (next IVI), and weekly for 4 weeks. In addition, SD-OCT and infrared images were obtained at each visit. A fluorescein angiography (FA), indocyanine green angiography (ICGA), and color fundus photography were also performed at baseline. Fluid metrics were quantified using an artificial intelligence (AI) algorithm. This allowed computations of IRF volumes, SRF volumes, and pigment epithelium detachment (PED) volumes at each visit.
Results
A total of 28 eyes of 26 patients were enrolled. Central retinal thickness (CRT), PED volume, and IRF and SRF volumes all significantly decreased one week after IVI. Maximal fluid reduction was reached on average at 1.93 weeks. At week 4 the values reached levels similar to baseline and the significant difference was lost. Large response variation was observed between the patients: the percentage of fluid resolution showed quartile limits at 36.6%, 70.1%, and 88.6%, respectively. No imaging factor was identified as significantly associated with the relative response. However, the amount of residual fluid was associated with more baseline SRF (r=0.76, p=0.0001) and larger PED (r=0.65, p=0.0001).
Conlusions
A majority of patients with so called refractory nAMD are in fact short term responders to treatment, with a maximum response after approximately two weeks and an early relapse at week four. However, presence of residual fluid was frequent, and an important proportion of patients showed little fluid change in between injections. The size of PED and the amount of SRF was associated with more residual fluid. Further studies are needed to understand the reasons for this truly refractory fluid.
Financial Disclosure
None
Comments
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