Prospective and dichotomous study of biomarkers with swept-source OCT and OCT-angiography in naive patients with diabetic macular edema

Abstract

Background: We used state-of-the-art high-resolution retinal imaging to explore the treatment (loading dose of aflibercept) of diabetic macular edema (DME) among treatment-naive patients. Swept-source (SS) OCT and OCT-Angiography (SS-OCTA) were performed, and a dichotomous analysis was conducted to compare responders and treatment-resistant patients (responsive and resistant). Furthermore, treatment responses were evaluated based on the subdivision of choroidal thickness.

Materials and methods: This prospective, noncomparative, interventional case series study examined the following biomarkers: best-corrected visual acuity (BCVA), central macular thickness (CMT), central choroidal thickness (CCT), avascular area of the superficial plexus (AASP), avascular area of the deep plexus (AADP), and vessel density (VD). Data from the baseline and 4-month examinations were compared.

Results: Twenty-eight eyes from 25 patients were included. Significant improvements were observed in BCVA (0.7250 ± 0.23 to 0.3957 ± 0.21; p < 0.000), CMT µm (339.04 ± 66.19 to 265.21 ± 55.75; p < 0.000), CCT µm (221.71 ± 69.69 to 209.07 ± 70.92; p < 0.000), VD (17.90 ± 7.82 to 15.35 ± 5.80; p < 0.038), AASP µm² (235,374 ± 91,299 to 157,326 ± 77,815; p < 0.000) and AADP µm² (996,335 ± 1,000,047 to 362,161 ± 277,225; p < 0.000). Dichotomous analysis revealed that 15 patients were responsive (53.57%), and 13 resistant (46.43%). There were no significant differences between any of the pretreatment biomarkers. In the subdivision of choroidal thickness, which ranged from 211 to 270 µm (group 3), we found greater reductions in the CCT, AADP and CD. The choroidal thickness ranged from 181 to 210 µm (group 2): BCVA and AASP exhibited the greatest reductions.

Conclusion: BCVA, CMT, CCT, AASP, AADP and VD were improved after treatment. The pretreatment biomarkers did not predict treatment response between the responsive and resistant. Regarding choroidal stratification, values within the normal range of CCT showed the greatest reductions, indicating that these values may be more responsive to treatment. Notably, this is the first study to analyze biomarkers provided by SS OCT and OCTA, stratify the choroid, and perform a dichotomous analysis.

Keywords: Aflibercept; Biomarkers; Choroidal thickness; Diabetic macular edema; Diabetic retinopathy; OCT angiography; Swept-source OCT.

Fig. 1

1A Multimodal Assessment with SS-OCT and SS-OCT-Angiography of a patient participating in this study, who received treatment with a loading dose of aflibercept (40 mg/ml) 0,05 ml/2 mg. 1A Pretreatment: Color Retinography: presence of diabetic retinopathy (microaneurysms and cotton wool exudates). 2A Posttreatment Color Retinography. All images that begin with number 1 correspond to pretreatment, and all images that begin with number 2 correspond to posttreatment. Image 1B B-Scan SSOCT: delimitation of macular thickness, where we observe the presence of diabetic macular edema. 2B: Posttreatment: B-scan without macular edema. 1C ETDRS map with central macular thickness of 402 µm, and 2C posttreatment with central macular thickness of 241 µm. 1D B-Scan with choroidal thickness delimitation, and 2D choroidal thickness posttreatment. 1E Central choroidal thickness of 224 µm pretreatment. And 2E: showing reduction to 214 µm. 1F Avascular Area of the Superficial Plexus pretreatment: 299.597 µm², and 2F: with posttreatment reduction to 197.358 µm². 1G Avascular Area of the Deep Plexus pretreatment: 655.767 µm², and 2G posttreatment with reduction to 257.871 µm². 1H B-Scan: presence of macular edema (intraretinal cysts), the red colors represent areas of greater flow according to the analysis performed by the Imaginet 6 software algorithm. 2H Posttreatment B-Scan, absence of macular edema. 1I Vessel Density Map = 21.10 corresponding to the central. 2I shows decreased Central Vessel Density = 13.43 and 1J Red Free pretreatment: presence of microaneurysms and cotton-wool exudates. 2J Red Free posttreatment