Association of dilated capillary area and anti-vascular endothelial growth factor treatment requirement for macular edema in branch retinal vein occlusion

Abstract

Purpose : To characterize dilated capillary area (DCA) and its relationship to macular edema in eyes with branch retinal vein occlusion (BRVO) using projection-resolved optical coherence tomographic angiography (PR-OCTA).

Methods : We included consecutive, treatment-naïve BRVO with at least 12-months of follow-up seen at a tertiary retina practice. We obtained 3×3-mm macular OCTA scans with a commercial 70-kHz spectral-domain OCT device (RTVue XR, Optovue, USA). The output volumetric OCTA data were further processed by our OCTA reading software (COOL-ART), including three-dimensional PR-OCTA algorithm to suppress projection artifacts, and automated directional graph-search layer segmentation to generate en face intermediate capillary plexus (ICP) and deep capillary plexus (DCP), followed by DCA detection and calculation (Figure 1). Scans at baseline, 3, 6 and 12-months were processed and included in this study. Eyes with central macular thickness greater than 300-microns were treated by anti-vascular endothelial growth factor (VEGF) injections with a pro re nata protocol.

Results : Thirty-three eyes, mean age was 69 years old and 21 females, were included in the study. Throughout the follow up period, DCA in the DCP was significantly greater than in the ICP at each time point during 12-months follow up (baseline; p=0.0087, 3, 6 and 12-months; all p<.0001) (Table 1). DCA in both plexuses did not change significantly during 12-months (ICP; p=0.4102, DCP; p=0.0595, one-way analysis of variance). The central retinal thickness (CRT) at baseline was positively correlated with the DCA in the DCP at 6 and 12-months (6-months; R²=0.25, p=0.0028, 12-months; R²=0.34, p=0.0004, Pearson correlation coefficient), but was not in the ICP. The number of anti-VEGF injections was positively correlated with the DCA in the ICP at baseline, 6 and 12-months (baseline; R²=0.24, p=0.0037, 6-months; R²=0.26, p=0.0027, 12-months; R²=0.35, p=0.0003) and in the DCP at 3, 6 and 12-months (3-months; R²=0.30, p=0.0013, 6-months; R²=0.47, p<.0001, 12-months; R²=0.45, p<.0001).

Conclusions : In BRVO, DCA is greater in the DCP compared to ICP. A greater DCA was correlated with increased anti-VEGF treatment requirement for macular edema, and also correlated with a greater CRT. These results suggest that DCA may be a quantifiable measure of venous congestion in BRVO.

This is a 2020 Imaging in the Eye Conference abstract.