Association of Retinal Ischemia with Retinal Neovascularization in Proliferative Diabetic Retinopathy

Abstract

Purpose : Ultra-widefield fluorescein angiography (UWFA) allows for improved evaluation of the peripheral retinal vasculature and assessing capillary non-perfusion. While the association of retinal ischemia with neovascularization is well-established, it is not known to what extent the location of capillary non-perfusion influences the localization of retinal neovascularization. The goal of this retrospective study was to explore whether the extent and distribution of retinal capillary non-perfusion is associated with neovascularization of the disc (NVD) or neovascularization elsewhere (NVE) in patients with proliferative diabetic retinopathy (PDR).

Methods : UWF angiograms of 96 eyes of 69 patients with PDR were reviewed by 2 masked, trained graders. Patients were excluded if they had any prior treatment with panretinal photocoagulation (PRP) or intravitreal anti-vascular endothelial growth factor (VEGF) treatment. Images were graded with ImageJ software for proportion of non-perfused area to total gradable area. Three perfusion zones were established based on previous published literature, to better assess the location of capillary non-perfusion and localization of neovascularization – zone 1, posterior pole; zone 2, mid periphery; zone 3, far periphery. Statistical significance was determined using clustered Wilcoxon tests.

Results : Of 96 eyes with PDR, retinal neovascularization was distributed as such: NVE, 56.3%; NVD, 11.5%; and both NVE and NVD, 30.2%. There was no significant difference in systemic factors such as age, gender, hemoglobin A1c, ethnicity, or mean arterial pressure between the three groups. NVD was associated with poorer visual acuity than NVE (p=0.011). Proportion of non-perfused retina was greater in all 3 zones in eyes with both NVD and NVE compared to eyes with NVE only (zone 1: 22.4 ± 12.0% vs. 15.6% ± 10.7%, p=0.025; zone 2: 34.8% ± 17.8% vs. 21.7% ± 17.9%, p=0.013; zone 3: 39.7% ± 23.5% vs. 24.4% ± 21.2%, p=0.036; all zones combined: 31.1% ± 14.1% vs. 20.0% ± 13.7%, p=0.011), but not when compared to NVD only.

Conclusions : Systemic factors do not appear to significantly influence the pattern of retinal neovascularization. The presence of both NVD and NVE is associated with a greater area of retinal capillary non-perfusion than NVE alone.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.