Optical Coherence Tomography Angiography Biomarkers Predict Anatomical Response to Bevacizumab in Diabetic Macular Edema

Abstract

Purpose

To identify biomarkers that may predict an early anatomical response to the treatment of diabetic macular edema (DME) with intravitreal bevacizumab (IVB) by means of optical coherence tomography angiography (OCTA).

Methods

This study is a retrospective study of treatment-naïve patients with DME who underwent 6 × 6 mm OCTA imaging of the macula at baseline and after three monthly IVB injections. Thirty-six eyes of 23 patients were included. Eyes that demonstrated evidence of an early anatomical response, consisting of a >10% decrease in central macular thickness (CMT) (n = 18), were compared with those eyes that failed to show such an improvement (n = 18).

Results

At baseline, early-response eyes had worse starting best-corrected visual acuity (BCVA, LogMAR 0.84 ± 0.41 versus LogMAR 0.51 ± 0.15, p = 0.004) and a larger CMT (490 ± 135 µm versus 356 ± 33 µm, p = 0.001), but smaller foveal avascular zones (FAZ) (0.309 ± 0.098mm versus 0.413 ± 0.095 mm, p = 0.003) compared with eyes that proved refractory to three monthly injections of IVB. The vascular density (VD) in both the foveal superficial and deep capillary plexuses was significantly greater in eyes that showed an early-treatment response compared with eyes that were non-responders (24.86 ± 6.90% versus 19.98 ± 7.13%, p = 0.045 and 32.30 ± 4.88% versus 26.95 ± 7.25%, p = 0.028, respectively). Early-treatment response to IVB was predicted by starting CMT (r²= 0.266, p = 0.001), FAZ size (r²= 0.234, p = 0.003), and VD in the superficial parafovea (r²= 0.217, p = 0.004) and deep fovea (r²= 0.157, p = 0.037).

Conclusion

Projection-resolved OCTA may be useful in predicting an early anatomical response of DME to treatment with IVB.

Keywords:

• anti-VEGF agents
• bevacizumab
• biomarkers
• diabetic macular edema
• macular ischemia
• macular perfusion
• optical coherence tomography angiography

Abbreviations

BCVA, best-corrected visual acuity; CMT, central macular thickness; DCP, deep capillary plexus; DM, diabetic mellitus; DME, diabetic macular edema; DR, diabetic retinopathy; FAZ, foveal avascular zone; IVB, intravitreal bevacizumab; OCTA, optical coherence tomography angiography; SCP, superficial capillary plexus; VD, vascular density; VEGF, vascular endothelial growth factor.

Data Sharing Statement

The data used in this study are available from the corresponding author upon reasonable request.

Ethics Approval and Consent to Participate

This study and report were approved by Cairo University Research Ethics Committee (Study ID: N-79-2017) and followed the tenets of the Declaration of Helsinki. All patients signed a written informed consent before inclusion of their data in the study.

Acknowledgments

An abstract for the initial results of this study was presented at the 2021 ARVO Imaging in the Eye virtual conference. The authors would like to thank Professors Khaled El Rakhawy, Shiyoung Roh, and Sarkis Soukiasian, as well as Carol Spencer, Lahey Hospital Librarian, for research support. D.J. Ramsey is the Harry N. Lee Family Chair in Innovation at the Lahey Hospital & Medical Center, Beth Israel Lahey Health.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis, and interpretation, or in all these areas; took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest for this work.

Additional information

Funding

There were no sources of funding for this work. Financial support: D.J.R. was supported by the Harry N. Lee Family Chair in Innovation at the Lahey Hospital & Medical Center, Beth Israel Lahey Health.