Vascular changes in eyes treated with dexamethasone intravitreal implant for macular edema after retinal vein occlusion

Objective: To evaluate the angiographic findings in eyes from 2 clinical trials of the dexamethasone intravitreal implant (DEX implant) 0.7 mg in the treatment of macular edema (ME) after branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO).

Design: Post hoc analysis of pooled data from 2 identical phase 3 clinical trials.

Participants: Patients with vision loss as a result of ME (≥ 6 weeks' duration) after BRVO or CRVO for whom angiographic data were available (n = 329 eyes).

Methods: Fluorescein angiography (FA) results assessed by masked, certified graders using standardized grading protocols.

Main outcome measures: The primary outcome measure in the parent studies was change from baseline in best-corrected visual acuity. Prospectively defined secondary outcomes included FA measurements (to assess macular capillary leakage, neovascularization, and nonperfusion) and optical coherence tomography results (to assess central retinal thickness [CRT]).

Results: At baseline, 42% of eyes in the DEX implant group and 38% of eyes in the sham group had unreadable assessments because of hemorrhage. At day 180, significantly fewer DEX implant-treated eyes (2%) than sham-treated eyes (9%) had unreadable assessments because of hemorrhage (P = 0.029). Among eyes with gradable assessments, the incidence of nonperfusion remained fairly steady from baseline to day 180. The proportion of eyes with active neovascularization increased from baseline to day 180 in the sham group, but stayed relatively constant in the DEX implant group (P = 0.026 for DEX vs. sham). The mean area of overall nonperfusion and the mean area of macular capillary nonperfusion increased from baseline to day 180 in both treatment groups (no statistically significant between-group difference). There was a statistically significant positive correlation between changes in macular leakage and changes in CRT in both the DEX implant group (r = 0.22; 95% confidence interval, 0.03-0.40; P = 0.023) and the sham group (r = 0.29; 95% confidence interval, 0.10-0.46; P = 0.003).

Conclusions: This study demonstrated that the clinical improvements observed with the DEX implant were accompanied by significant improvements in vascular parameters and suggests that treatment with the DEX implant may be associated with some clinically significant improvements in angiographic findings, specifically active neovascularization.