Clinical effect of conbercept on improving diabetic macular ischemia by OCT angiography

Abstract

Purpose Varying degrees of macular ischemia generally occur in diabetic retinopathy (DR). This study aims to evaluate the effect of conbercept with 3+ pro re nata (PRN) on macular perfusion status in patients with diabetic macular edema (DME) and quantitatively assess changes in foveal avascular zone (FAZ) areas and capillary density in macular regions by applying OCT angiography (OCTA). Methods Fifty patients were divided into ischemic (n=31) and non-ischemic (n=19) groups according to the presence of ischemia on OCTA at baseline. All patients received interval injection of 0.5mg of conbercept with 3+ PRN principle. The FAZ areas and macular vessel density measured using OCTA were evaluated at baseline, 3 months, and 6 months after treatment in both groups. Results At months 3 and 6, the FAZ area in the ischemic group changed from 0.510±0.171mm 2 to 0.441±0.158mm 2 then to 0.427±0.153mm 2 (p=0.003, p=0.296); in the non-ischemic group, it remained stable (p=0.269, p=0.926). The superficial vessel density changed from 41.1%±4.1% to 42.5%±4.7% then to 42.6%±4.6% (p=0.043, p=0.812), and the deep vessel density changed from 40.7%±4.4% to 42.3%±3.6% then to 42.3%±4.7% (p=0.072, p=0.961) in the ischemic group. In the non-ischemic group, the superficial vessel density changed from 44.8%±3.2% to 46.0%±3.5% then to 45.7%±3.3% (p=0.108, p=0.666), whereas the deep vessel density changed from 43.6%±3.6% to 43.8%±3.2% then to 43.5%±4.5% (p=0.882, p=0.736). Reperfusion in macular nonperfusion areas was observed. Conclusion Anti–vascular endothelial growth factor treatment may have a positive effect on macular perfusion status, improve macular ischemia, and promote reperfusion appearance in patients with DME. Furthermore, OCTA had advantages in quantifying and calculating blood flow index in the study of macular perfusion status.

Optical Coherence Tomography Angiography of Macular Perfusion Changes after Anti-VEGF Therapy for Diabetic Macular Edema: A Systematic Review

“…A total of 16 studies that evaluated the effect of intravitreal anti-VEGF injections for DME on the macular perfusion using OCTA in the period between January 2016 and November 2020 were included [12,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Figure 3 shows the PRISMA flowchart summarizing the results of the search strategy and reasons for exclusion.…”

“…Most of the included studies (14/16, 87.5%) used the RTVue XR Avanti Spectral domain-OCTA machine (Optovue, Inc., Fremont, CA, USA), while two studies (2/16, 12.5%) used the Triton OCTA machine (Topcon Inc, Japan). Only one study compared ischemic to nonischemic eyes [37], while one study compared OCTA to FA findings [41]. The duration of treatment and type of anti-VEGF agent used were variable, and some studies utilized multiple anti-VEGF agents.…”

“…In a prospective study by Zhu et al [37], the effect of conbercept injections on the macular perfusion of patients with DME was assessed using OCTA scanning. Patients were divided into two subgroups: ischemic (31 patients) and nonischemic (19 patients) according to macular perfusion findings on FA and received 3 monthly conbercept injections followed by pro re nata regimen for another 3 months.…”

“…Used only 6 × 6 scans, did not use automated image alignment, used built-in machine VD measurements. [37] Mirshani et al…”

“…9 Journal of Diabetes Research conflicting results with 7 studies showing stable or improved macular perfusion following treatment [32][33][34][35][36][37][38], 7 studies showing worsening of macular perfusion following treatment [12,[39][40][41][42][43][44], and 2 studies showing conflicting results [45,46]. This could have been due to study design differences, differences in patients' characteristics and inclusion criteria, or methods of image analysis and vascular density quantification.…”