Abstract
Purpose :
To evaluate the effect of monthly anti-vascular endothelial growth factor (VEGF) treatment for proliferative diabetic retinopathy (PDR) on quantitative metrics of retinal microvasculature using optical coherence tomography angiography (OCTA).
Methods :
Diabetes mellitus (DM) eyes with PDR treated with monthly anti-VEGF injections over 6 months from Jan. 2016-Dec. 2018 were included in this retrospective study. 3x3 mm OCTA scans with signal strength > 7 were acquired (Cirrus 5000 Angioplex, Carl Zeiss Meditec, Dublin, CA) at baseline and at 6 months. Automated segmented scans were averaged with registration for the superficial retinal layer. Quantitative parameters including 6-month interval change in the size and circularity of the foveal avascular zone (FAZ), parafoveal vessel density (VD) and perfusion density (PD) were analyzed. Univariate and multivariate linear regression with clustering on the individual level were performed to correlate quantitative metrics to baseline demographics.
Results :
19 eyes (14 patients, 10 male, 11 on insulin, 2 on hemodialysis (HD), mean age of 56 (range 40-77), mean HgbA1C 8.6 (±2.2)) were included. 5 had previous anti-VEGF, 1 had previous vitrectomy and 2 had previous PRP. 10 eyes had recurrence of PDR during follow-up, 4 of which required subsequent PRP but none required vitrectomy. Average overall follow-up was 54.0 months (±22.0) and eyes received an average of 9 (±4.4) injections during their entire follow-up.
Multivariate regression showed, when controlling for male gender and HD use, subjects with type 2 DM had a 1.83 (mm/mm2) lower interval change in the inferior ETDRS VD versus those with type 1 DM (p=0.017). Type 2 DM subjects also had less change in mean central (-1.19, p=0.044) and full mean (-1.77, p=0.0001) VD. When controlling for the confounding variable of male gender and presence of Type 2 DM, subjects on hemodialysis had a 1.83 lower change in inner inferior ETDRS VD (p=0.054). When controlling for presence of type 2 DM, subjects on HD had a 0.041 unit lower inferior ETDRS PD (p = 0.020). Subjects using insulin had a 0.13 mm2 lower change FAZ size (p=0.025).
Conclusions :
After monthly anti-VEGF treatments over 6 months, preliminary findings suggest Type 2 DM, HD and insulin use may have a protective effect against changes in OCTA.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.