Intravitreal Bevacizumab as Adjunctive Therapy for Bleb Survival in Trabeculectomy in Rabbit Eyes
Margarita Echavez, MD, Manuel Agulto, MD, and Ma. Imelda Veloso, MD
Objectives
To determine the effect of intravitreally administered bevacizumab, alone or as adjunct to mitomycin-C, after trabeculectomy on bleb survival and histology in rabbit eyes.
Methods
An experimental, interventional, comparative, animal study consisting of 16 rabbit eyes underwent trabeculectomy, 8 of which were enhanced with intra-operative mitomycin-C. Eyes were randomized to receive intravitreal bevacizumab at a concentration of 12.5 mg/mL. Intraocular pressure (IOP), bleb dimensions, and vascularity grading were obtained. IOP was recorded as a ratio of the IOP of the experimental operated eye divided by the IOP of the contralateral control eye (IOPratio) as a function of time. Bleb morphology was recorded as a percentage of the maximum estimated bleb volume (% Bleb) over time. Bleb failure occurred if IOPratio ≥0.8, or if % Bleb =0. Eyes were enucleated and submitted for histopathological analysis.
Results
In terms of IOP, mean bleb survival of the plain trabeculectomy group was 7.00(±0.00) days compared to 11.00 (±1.00) days in the intravitreal bevacizumab group (p=0.02). In mitomycin-C-enhanced trabeculectomy eyes, the mean bleb survival was 15.25 (±0.75) days compared to 19.00 days in the intravitreal bevacizumab group (p=0.002). In terms of bleb morphology, bleb survival were 9 (±1.00) and 13 (±0.00) days for the plain trabeculectomy and intravitreal bevacizumab groups respectively (p=0.02); and 18.25 (±0.75) and 20.00 (±0.58) days for the trabeculectomy with mitomycin and intravitreal bevacizumab groups respectively (p=0.11). Mean vascularity grading were 1.67 (± 0.33) and 1.33 (± 0.33) for the plain trabeculectomy and bevacizumab groups and 1.50 (±0.59) and 1.25 (±0.25) for the mitomycin and bevacizumab groups respectively (p=0.72). Histologic analysis showed less fibroblast count for eyes treated with bevacizumab.
Conclusion
Intraoperative intravitreal bevacizumab as adjunctive therapy after trabeculectomy, whether plain or enhanced with mitomycin-C, was associated with improved bleb survival rates in the rabbit model.
Keywords:Trabeculectomy, Wound healing, Vascular endothelial growth factor, Bevacizumab, Bleb failure