Abstract
BackgroundTo examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities (IRMAs) in response to anti-vascular endothelial growth factor (anti-VEGF) treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes.MethodsIn this retrospective study, IRMAs were evaluated with multimodal imaging (fundus photography, fluorescein angiography, OCTA) in treatment-naïve diabetic eyes before and after anti-VEGF treatment for diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR) and compared to diabetic control eyes with similar diabetic retinopathy (DR) severity that did not receive anti-VEGF therapy. The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline, then after anti-VEGF therapy in treated eyes or after observation in control eyes. Characterization of interval changes in an IRMA were based on the following parameters: branching, vessel caliber and area of adjacent capillary non-perfusion.ResultsThe treated group included 45 IRMA foci from 15 eyes of 11 patients, while the control group included 27 IRMA foci from 15 eyes of 14 patients. Following anti-VEGF treatment, enface OCTA demonstrated that 14 foci of IRMA (31%) demonstrated regression with normalization of appearance of the capillary bed, 20 IRMAs (44%) remained unchanged, six IRMAs (13%) progressed with enlargement or development of new IRMAs and five IRMAs (11%) demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out. In the control group, 17 IRMA (63%) remained stable, 8 IRMAs (29.6%) progressed and 2 experienced total obliteration (7.4%). The difference in rank order between the two groups was statistically significant (p = 0.022).ConclusionsIn eyes with DR status post anti-VEGF therapy, foci of IRMAs have a variable course demonstrating one of four possible outcomes: regression, stability, progression or complete obliteration. In contrast, none of the untreated control diabetic eyes demonstrated regression of IRMAs, consistent with known progression of DR severity in high risk eyes. Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as well as the response to anti-VEGF treatment.
Highlights
To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities (IRMAs) in response to anti-vascular endothelial growth factor treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes
The Early Treatment of Diabetic Retinopathy Study (ETDRS) provided standard photographs 8A and 8B for IRMAs, which was defined as tortuous intraretinal vascular segments located in standard fields 3–7, with caliber ranging from barely visible to 31 μm based on color stereoscopic photograph evaluation [3, 4]
Optical coherence tomography angiography (OCTA) is a noninvasive, depth-resolved imaging modality that can visualize the retinal microvasculature in great detail, and has been shown to be useful in Diabetic retinopathy (DR) to examine neovascularization, capillary non-perfusion, and IRMAs with higher resolution compared to conventional fluorescein angiography (FA) [8]
Summary
To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities (IRMAs) in response to anti-vascular endothelial growth factor (anti-VEGF) treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes. Intraretinal microvascular abnormalities (IRMAs) are a common finding in the eyes of diabetics with severe non-proliferative (NPDR) and proliferative diabetic retinopathy (PDR). The Early Treatment of Diabetic Retinopathy Study (ETDRS) provided standard photographs 8A and 8B for IRMAs, which was defined as tortuous intraretinal vascular segments located in standard fields 3–7, with caliber ranging from barely visible to 31 μm based on color stereoscopic photograph evaluation [3, 4]. Optical coherence tomography angiography (OCTA) is a noninvasive, depth-resolved imaging modality that can visualize the retinal microvasculature in great detail, and has been shown to be useful in DR to examine neovascularization, capillary non-perfusion, and IRMAs with higher resolution compared to conventional FA [8]
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