Conbercept improves macular microcirculation and retinal blood supply in the treatment of nonischemic branch retinal vein occlusion macular edema

Abstract

Purpose: To investigate the effect of conbercept on macular microvascular system and retinal blood supply in the treatment of nonischemic branch retinal vein occlusion macular edema (BRVO-ME).

Methods: Patients were divided into three groups: group A (containing 12 nonischemic BRVO-ME eyes), group B (containing contralateral 12 healthy eyes), and group C (containing 30 cataract eyes to obtain normal aqueous humor cytokine levels). Group A received monthly intravitreal injections of conbercept for 3 months. General data and best-corrected visual acuity (BCVA) were compared among the three groups. Optical coherence tomography angiography (OCTA) results (including central macular thickness [CMT], retinal vascular density and perfusion, and foveal avascular zone [FAZ]) at baseline were compared among groups A and B. Aqueous humor cytokine levels (including VEGF, IL-8, PDGF-AA, TNF-α, and ANGPTL-4) at baseline were compared between groups A and C. Moreover, BCVA, OCTA results, and aqueous humor cytokine levels of group A before and after conbercept treatment were compared.

Result: At baseline, group A had a significantly worse BCVA, lower retinal vascular density and perfusion, and numerically larger CMT and FAZ area comparing to the group B, and had a higher aqueous cytokine level (IL-8, VEGF, and ANGPTL-4) comparing to the group C (all ps < 0.05). After the injection of conbercept, group A presented a better BCVA (at initial diagnosis vs. after three conbercept injections: 1.16 ± 0.51 vs. 0.81 ± 0.30, logMAR, p < 0.05), higher retinal vascular density (11.56 ± 4.73 vs. 15.88 ± 2.31, mm^-1 , p < 0.05) and perfusion (0.28 ± 0.12 vs. 0.39 ± 0.06, mm² , p < 0.05), smaller CMT (504.92 ± 184.11 vs. 219.83 ± 46.63, mm² , p < 0.05), as well as a lower levels of VEGF (before first injection vs. before third injection: 113.84 [70.81, 235.4] vs. 3.94 [3.56, 8.07], pg/ml, p < 0.05) and ANGPTL-4 (45,761 [7327.5, 81,402.5] vs. 25,015.5 [6690, 43,396], pg/ml, p < 0.05). However, the average FAZ area of group A expanded (at initial diagnosis vs. after three conbercept injections: 0.41 ± 0.14 vs. 0.62 ± 0.36, mm² , p < 0.05).

Conclusion: This study demonstrated that intraocular injection of conbercept could effectively improve macular microcirculation and increase retinal blood supply in the treatment of nonischemic BRVO-ME based on the combination of visual acuity, OCTA parameters, and aqueous humor cytokine assay results. However, further study with a larger sample size and longer observation period is still needed in the future.

Keywords: ANGPTL-4; OCTA; branch retinal vein occlusions; conbercept; macular edema.