Abstract
Objective To evaluate macular perfusion changes following intravitreal bevacizumab injections for diabetic macular edema (DME) using spectral domain optical coherence tomography angiography (SD-OCTA). Methods This study was a prospective noncomparative interventional case series. Treatment naïve patients with DME underwent full ophthalmological examination and SD-OCTA scanning at baseline and after 3 intravitreal bevacizumab injections. Both the 6 × 6 and 3 × 3 mm macular scan protocols were used. Pretreatment and posttreatment OCTA images were automatically aligned using a commercially available retina alignment software (i2k Align Retina software); then the fractal dimension (FD), vascular density (VD), and skeleton VD changes were obtained at the full retinal thickness (Full) and superficial (SCP) and deep (DCP) capillary plexuses after processing images using a semiautomated program. The foveal avascular zone (FAZ) was manually measured and FD was calculated using the FracLac plugin of ImageJ. Results Forty eyes of 26 patients were included. Following injections, there were an 8.1% increase in FAZ, 1.3% decrease in FD-Full and FD-SCP, 1.9% decrease in FD-DCP, 8% decrease in VD-Full, 9.1% decrease in VD-SCP, 10.6% decrease in VD-DCP, 13.3% decrease in skeleton VD-Full, 12.5% decrease in skeleton VD-SCP, and 16.3% decrease in skeleton VD-DCP in the 6 × 6 mm macular area and a 2.6% decrease in FD-Full, 3.4% decrease in FD-SCP, 11.5% decrease in VD-Full, 14.3% decrease in VD-SCP, and 25.1% decrease in skeleton VD-SCP in the 3 × 3 mm macular area which were all statistically significant (p < 0.05). Using univariate and multivariate analysis, the pretreatment FD, VD, and skeleton VD at each capillary layer significantly negatively correlated with the change in FD, VD, and skeleton VD at the corresponding capillary layer, respectively (p < 0.05). Conclusion OCTA is a useful noninvasive tool for quantitative evaluation of macular perfusion changes following DME treatment. This trial is registered with NCT03246152.
Highlights
Optical coherence tomography angiography (OCTA) is a relatively new noninvasive modality capable of analyzing the different retinal capillary layers quantitatively at a higher resolution compared to conventional fluorescein angiography (FA) [17]. e Evaluation of the Effect of Intravitreal Injections of Anti-vascular endothelial growth factor (VEGF) on Macular Perfusion in Diabetic Patients using OCTA (IMPACT) study was a prospective noncomparative interventional case series done to evaluate the effect of repeated intravitreal bevacizumab injections on the macular perfusion of diabetic patients using OCTA
Forty eyes of 26 patients successfully completed the study with the 6 × 6 mm scan protocol, while 9 eyes of 6 patients successfully completed the study with the 3 × 3 mm scan protocol, with sufficiently high pre- and posttreatment OCTA image quality
Long-term treatment with anti-VEGF agents has been shown to improve the DR severity score (DRSS), studies have shown that they are not able to completely halt the progressive retinal capillary closure associated with diabetic retinopathy (DR) but to only slow it down compared to sham or laser [15, 16, 33]. is was consistent with our findings where we found a significant decrease in retinal vascular density associated with antiVEGF injections, whether this decrease could have been more in the absence of injections or using other treatment modalities could not be assessed in our study due to the absence of a control group
Summary
To evaluate macular perfusion changes following intravitreal bevacizumab injections for diabetic macular edema (DME) using spectral domain optical coherence tomography angiography (SD-OCTA). Treatment naıve patients with DME underwent full ophthalmological examination and SD-OCTA scanning at baseline and after 3 intravitreal bevacizumab injections Both the 6 × 6 and 3 × 3 mm macular scan protocols were used. Most of the studies evaluating the effect of repeated intravitreal anti-VEGF injections on the macular perfusion status in diabetics have relied on qualitative analysis of perfusion using fluorescein angiography (FA) [14,15,16]. E Evaluation of the Effect of Intravitreal Injections of Anti-VEGF on Macular Perfusion in Diabetic Patients using OCTA (IMPACT) study was a prospective noncomparative interventional case series done to evaluate the effect of repeated intravitreal bevacizumab injections on the macular perfusion of diabetic patients using OCTA Optical coherence tomography angiography (OCTA) is a relatively new noninvasive modality capable of analyzing the different retinal capillary layers quantitatively at a higher resolution compared to conventional FA [17]. e Evaluation of the Effect of Intravitreal Injections of Anti-VEGF on Macular Perfusion in Diabetic Patients using OCTA (IMPACT) study was a prospective noncomparative interventional case series done to evaluate the effect of repeated intravitreal bevacizumab injections on the macular perfusion of diabetic patients using OCTA
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