Intravitreal bevacizumab for surgical treatment of severe proliferative diabetic retinopathy

Abstract

The purpose of this study is to evaluate the role, the safety and the effectiveness of intravitreal bevacizumab (IVB) injections as an adjunct to vitrectomy in the management of severe proliferative diabetic retinopathy (PDR). Case-Control Study Randomized controlled trial performed on 72 eyes of 68 patients affected by vitreous haemorrhage (VH) and tractional retinal detachment (TRD), which occurred as a consequence of active proliferative diabetic retinopathy (PDR). We randomly assigned eligible patients in a 1: 1: 1 ratio to receive a sham injection or an intravitreal injection of 1.25 mg of bevacizumab, either 7 or 20 days before the vitrectomy. In order to obtain three homogeneous groups of surgical complexity, we assigned to the following preoperative parameters a score from 0 to 3: a) vitreous haemorrhage, b) prior retinal laser-photocoagulation, c) morphological types of retinal detachment such as focal, hammock, central diffuse, table-top. Complete ophthalmic examinations and color fundus photography were performed at baseline and 1, 6, 12, and 24 weeks after the surgery. Intraoperative management, safety, efficacy of IVB at different time injection as an adjunct to vitrectomy in the management of severe PDR RESULTS: Group A (sham injection): intraoperative bleeding occurred in 19 cases (79.1%), the use of endodiathermy was necessary in 13 patients (54.1%), relaxing retinotomy was performed on one patient (4.1%), and in four cases (16.6%) iatrogenic retinal breaks occurred. The surgical mean time was 84 minutes (SD 12 minutes). Group B (bevacizumab administered 7 days before vitrectomy): intraoperative bleeding occurred in two cases (8.3%) and the use of endodiathermy was necessary in two patients (8.3%). No iatrogenic breaks occurred during the surgery. The surgical mean time was 65 minutes (SD 18 minutes). Group C (bevacizumab administered 20 days before vitrectomy): intraoperative bleeding occurred in three cases (12.5%), the use of endodiathermy was necessary in three patients (1.5%), and an iatrogenic break occurred in one patient (4.1%) while the delamination of fibrovascular tissue was being performed. The surgical mean time was 69 minutes (SD 21 minutes). The average difference in the surgical time was statistically significant between group A and group B (p = 0.025), and between group A and group C (p = 0.031). At the end of the surgery, the retina was completely attached in all eyes. At the 6-month follow-up, we observed the development of tractional retinal detachment (TRD) in one out of 24 patients from group C (4%). A preoperative intravitreal injection of bevacizumab may represent a new strategy for the surgical treatment of severe PDR by reducing retinal and iris neovascularization: this would make surgery much easier and safer, thus improving the anatomical and functional prognosis. According to our study, the best surgical results are achieved performing the IVB 7 days preoperatively.