Intravitreal Bevacizumab as Adjunctive Therapy for bleb survival in trabeculectomy in rabbit eyes

Objective@#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.

Efficacy and Safety of Subconjunctivally Injected 5-fluorouracil after Mitomycin C Trabeculectomy in High Risk Patients

To determine the safety and efficacy of using subconjunctival 5- fluorouracil(5-FU) injection on high risk eyes for filtration failure who had undergone trabeculectomy with intraoperative mitomycin C(MMC), we conducted a retrospective analysis of 17 eyes of 17 consecutive patients. Intraoperative MMC exposure (0.4mg/ml) was followed by supplemental postoperative 5-FU injection as necessary to titrate bleb vascularity and intraocular pressure (IOP). Exposure time to MMC was 2 to 5 minutes based on multiple preoperative and intraoperative risk factors. Postoperative 5-FU was administered by subconjunctival injection(5mg) adjacent to or into the bleb in a weekly interval(mean 4 injections, range 2-5 injections). Mean follow-up time was 8.6 months. Overall mean preoperative IOP was 27.1+/-7.2mmHg compared with mean postoperative IOP of 12.3+/-7.4mmHg. Fifteen eyes(88%) achieved a final IOP < OR =21mmHg without medicatio and 11 eyes(64%) achieved a final IOP< OR =12mmHg. Complications developed after 5-FU injections included corneal epithelial defect in 2 eyes (12%), hypotony (IOP< OR =5, at least 2 visits) in 2 eyes(12%), and bleb leakage in 1 eye(6%). No patient had a hypotony induced maculopathy, hyphema or choroidal effusion. Our data suggest that postoperative 5-FU may be safely used adjunctively following MMC trabeculectomy in carefully selected patients, and may improve the overall success rate with high risk trabeculectomy.