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

Abstract

Background: 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 optical coherence tomography 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 intravitreal injections of 0.5 mg 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 ± 0.171 mm² to 0.441 ± 0.158 mm² then to 0.427 ± 0.153 mm² (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. Furthermore, OCTA had advantages in quantifying and calculating blood flow index in the study of macular perfusion status.

Keywords: Conbercept; Diabetic retinopathy; Macular ischemia; OCT angiography.

Fig. 1

Changes in FAZ area after anti-VEFG therapy

Fig. 2

FAZ area clearly decreasing in the eye of a 59-year-old male, 6 months after receiving conbercept treatment. Notes: OCT angiography images (a–c) depict macular ischemia and apparent FAZ expansion captured in 6 × 6 mm2 sections in the macular area at month 0, Q-score = 8/10. a FAZ area with 0.604 mm2, showing severe FAZ area expansion and arch ring capillary network breakage; b Superficial capillary plexus (ILM-IPL), vessel density of 39.2%; c Deep capillary plexus (IPL-OPL), vessel density of 43.5%;. At month 6, OCT angiography images (a’–c’) showed FAZ area decrease, Q-score = 9/10. a’ FAZ area with 0.464 mm2; b Superficial capillary plexus vessel density of 40.4%; c Deep capillary plexus vessel density of 43.1%

Fig. 3

Changes of vessel density in both superficial plexus and deep plexus in all patients

Fig. 4

Reperfusion occurred in the right eye of a 53-year-old male, 6 months after receiving conbercept treatment. Red arrows and boxes indicate growth of new blood flow signal and reperfusion in the macular nonperfusion areas. OCT angiography images (a–c) at baseline illustrate the macular nonperfusion area, Q-score = 8/10. a Superficial capillary plexus, VD = 45.7%; b Deep capillary plexus, VD = 39.6; c Full retinal capillary plexus. OCT angiography images a’–c’ at month 6 indicate reperfusion in previous macular nonperfusion areas, Q-score = 8/10. a Superficial capillary plexus, VD = 45.5%; b Deep capillary plexus, VD = 40.2%; c Full retinal capillary plexus