Panretinal photocoagulation versus panretinal photocoagulation plus intravitreal bevacizumab for high-risk proliferative diabetic retinopathy

Abstract

Aim: To evaluate the effects of panretinal photocoagulation (PRP) compared with PRP plus intravitreal bevacizumab (IVB) in patients with high-risk proliferative diabetic retinopathy (PDR) according to the Early Treatment Diabetic Retinopathy Study criteria.

Methods: The data were collected retrospectively from the eyes of high-risk PDR patients, which were divided into two groups. After treated with standard PRP, the eyes were randomly assigned to receive only PRP (PRP group) or PRP plus intravitreal injection of 1.25 mg of bevacizumab (PRP-Plus group). Patients underwent complete ophthalmic evaluation, including best corrected visual acuity (BCVA), intraocular pressure (IOP), and new vessel size in fluorescein angiography (FA) and optical coherence tomography for the assessment of central subfield macular thickness (CSMT) at baseline and at weeks 12 (±2), 16 (±2), 24 (±2) and 48 (±2). Main outcome measures also included vitreous clear-up time and neovascularization on the disc (NVD) regression time. Adverse events associated with intravitreal injection were investigated.

Results: Thirty consecutive patients (n=36 eyes) completed the 48-week follow-up. There was no significant difference between the PRP and PRP-Plus groups with respect to age, gender, type or duration of diabetes, area of fluorescein leakage from active neovascularizations (NVs), BCVA or CSMT at baseline. The mean vitreous clear-up time was 12.1±3.4wk after PRP and 8.4±3.5wk after PRP combined with IVB. The mean time interval from treatment to complete NVD regression on FA examination was 15.2±3.5wk in PRP group and 12.5±3.1wk in PRP-Plus group. No significant difference in CSMT was observed between the groups throughout the study period. However, the total area of actively leaking NVs was significantly reduced in the PRP-Plus group compared with the PRP group (P<0.05). Patients received an average of 1.3 injections (range: 1-2). Ten eyes (27.8%) underwent 2 injections. Two eyes had ocular complication of PDR progression to dense vitreous hemorrhage (VH). No major adverse events were identified.

Conclusion: The adjunctive use of IVB with PRP is associated with a greater reduction in the area of active leaking NVs than PRP alone in patients with high-risk PDR. Short-term results suggest combined IVB and PRP achieved rapid clearance of VH and regression of retinal NV in the treatment of high-risk PDR. Further studies are needed to determine the effect of repeated intravitreal bevacizumab injections and the proper number of bevacizumab injections as an adjuvant.

Keywords: high-risk proliferative diabetic retinopathy; intravitreal bevacizumab; neovascularization on the disc; panretinal photocoagulation.

Figure 1. A 53-year-old female patient with bilateral high-risk PDR

A-D: Actively leaking new vessels were observed in both eyes at baseline. She presented with sever NVE and a little VH in the both eyes, and FA showed large regions of NVE leakage compatible with the diagnosis of high-risk PDR. She received the standard PRP in both eyes. After 1mo, in both eyes, VH remarkably cleared, and visual acuity improved from 0.3 at baseline to 0.5. An obvious FLA reduction was found in both eyes but no NVE completely regression. IVB injection was added to the treatment of her left eye and supplemental photocoagulation for her right eye. E: At week 12, a marked decrease of leakage was noted in the left eye. F: In her right eye, leakage from NV was slightly decreased but still actively persistent. Six months after bevacizumab injection, VH completely cleared up and FA disclosed no more fluorescein leakage from NVE in the left eye.

Figure 2. A 57-year-old male patient presented with high-risk PDR and severe NVD

The eye with severe NVD was compatible with the diagnosis of high-risk PDR. FA showed profuse NVD leakage and a large area of capillary dropout. The NVD was slightly decreased but still actively persistent after PRP. Complete NVD regression without any fluorescein leakage was noted one month after one intravireal injection of bevacizumab at the week 8.

Figure 3. Distributions of the intraindividual differences

A: The 12, 16 and 24wk after treatment-baseline of BCVA; B: FLA from active neovascularization; C: CSMT (µm) for PRP and PRP-Plus IVB. The horizontal line across the data is the mean±SD.