Hemodynamic Effects of Anti-Vascular Endothelial Growth Factor Injections on Optical Coherence Tomography Angiography in Diabetic Macular Edema Eyes

Abstract

Purpose To evaluate retinal hemodynamic responses to anti-vascular endothelial growth factor (VEGF) injection in eyes with diabetic macular edema using optical coherence tomography angiography (OCTA). We performed a comparison of two different thresholding methods to identify the most accurate for studying the vessel density (VD) in diabetic macular edema eyes. Methods The study prospectively included 26 eyes of 22 subjects (aged 60.2 ± 13.7 years) who underwent OCTA scan before and after anti-VEGF injection (mean interval between OCTA = 31.1 ± 17.3 days). We analyzed adjusted flow index, VD, and Skeletonized vessel length density in the parafoveal area (3-mm annulus with a 1-mm inner circle), along with full-thickness fovea avascular zone area and central foveal thickness (CFT). Using averaged scans VD as the ground truth, we compared two different algorithms for VD at the different plexuses. Longitudinal changes were assessed using a generalized linear model correcting for central foveal thickness and Q-score. Results We found significantly decreased adjusted flow index in the DCP layer ( P = 0.010) at the follow-up. Furthermore, foveal avascular zone ( P < 0.001) and central foveal thickness ( P = 0.003) showed significant decrease on follow-up compared with baseline. Comparing the thresholding algorithms showed that vessel length density–based thresholding was more accurate for quantifying the DCP VD. Conclusions The adjusted flow index decreased significantly in the DCP layer on follow-up OCTA scan, suggesting vascular flow disruption and decreased deep retinal perfusion after anti-VEGF injection. Our results also highlight the fact that the choice of thresholding method is particularly critical for DCP quantification in eyes with diabetic macular edema. Translational Relevance Findings confirmed impaired deep retinal capillary flow after anti-VEGF injection.

Short Term Effect of Pre-Operative Anti-VEGF on Angiogenic and Fibrotic Profile of Fibrovascular Membranes of Proliferative Diabetic Retinopathy

“… 28 Accordingly, the anticipated phenotype with increased expression of CDH5 and EDN1 would be constricted vessels with decreased leakage, contributing to the beneficial effects of pre-operative anti-VEGF injection. This is corroborated by a recent study from our group that showed intravitreal anti-VEGF injections are associated with decreased blood flow at the deep capillary plexus, 29 in line with decreased blood flow as a consequence of vasoconstriction, highlighting the potentially complex hemodynamic consequences of anti-VEGF injections.…”

“…5 ). Whereas systemic hypertension has been anecdotally associated with IVB, it is more likely that heightened EDN1 expression in the eye would contribute to retinal vasoconstriction and reduced retinal blood flow, 28 , 29 although this needs further confirmation.…”

Changes in central retinal and choroidal OCT/OCTA parameters following intravitreal bevacizumab injection in diabetic macular edema

“…Another case-control study also reported signi cantly lower parafoveal VD in both SCP and DCP among patients with DME (3). Regarding the effect of anti-VEGF on the vascular ow in retinal capillary plexuses, different studies reported contradictory results (3,10,30,31). The inconsistent results among the studies could be due to differences in study design, inclusion criteria, and consideration of confounding factors (diurnal variation, SSI, and intraocular pressure-associated variation ( 21)), the utilized OCTA device, and the scanned area.…”

Quantitative Parameters Relevant for Diabetic Macular Edema Evaluation by Optical Coherence Tomography Angiography

“…Regarding the influence of various treatment modalities on the quantitative parameters assessed by OCTA, in patients with DME treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF), the first-line treatment for DME at the moment, one study concluded that the vessel length density (VLD)—based thresholding was more accurate for quantifying the retinal vascular changes after a single injection [ 24 ]. However, several studies showed no significant changes in this parameter after the anti-VEGF treatment [ 24 ].…”