Abstract
Purpose:
Vitreous surgery in diabetes can be complicated by iatrogenic retinal breaks and vitreous cavity haemorrhage. Trials of bevacizumab as a pre-operative adjunct to surgery have yielded variable results. Concerns remain over the safety of anti-vascular endothelial growth factor (VEGF) agents in this condition with reports of exacerbation of pre-existing tractional retinal detachment. The aim of this pilot study was to assess the impact of ranibizumab pre-treatment on the outcome of surgery for advanced proliferative diabetic retinopathy.
Methods:
This was a randomized, double-masked clinical trial. Thirty eyes of 30 subjects with proliferative diabetic retinopathy having vitrectomy and delamination of fibrovascular complexes were randomized to ranibizumab intravitreal injection or control (saline subconjunctival injection) 7±1 days prior to surgery. The primary outcome measure was best corrected ETDRS visual acuity at 12 weeks post-op. Secondary outcome measures comprised technical difficulty of surgery; intra-operative and post-operative haemorrhage; extent of tractional retinal detachment; extent of retinal neovascularization; vitreous and plasma levels of VEGF and related cytokines.
Results:
Mean (SD) visual acuity 12 weeks following surgery for ranibizumab treated subjects was 53 (21) letters and for control subjects was 47 (25). We detected no difference in duration or technical difficulty of surgery; the degree of intraoperative haemorrhage was similar between the two groups. Persisting vitreous cavity haemorrhage was evident in 2 subjects in the control group at 12 weeks, and in none of the ranibizumab group. Four subjects in the ranibizumab group had no visible retinal neovascularization at trial exit; one in the control group. Vitreous levels of VEGF and interleukin (IL)-1α were lower following ranibizumab treatment. We identified no progression of tractional retinal detachment following ranibizumab and no new safety issues.
Conclusions:
Ranibizumab treatment as an adjunct to diabetic vitrectomy appears safe and may lead to improved visual acuity and reduced vitreous cavity haemorrhage at 12 weeks post-op. Reduced levels of VEGF and IL-1α were found following ranibizumab administration. These findings will help inform the design of an appropriately powered clinical trial.
Keywords: 762 vitreoretinal surgery •
499 diabetic retinopathy •
748 vascular endothelial growth factor