Subconjunctival High Dose Plasminogen Activator in Rabbit Filtration Surgery

The primary cause of failure in glaucoma filtration surgery is fibroblastic proliferation and subconjunctival fibrosis at the bleb site resulting in decreased aqueous flow. We evaluated New Zealand white rabbits in a masked, placebo controlled pilot study to determine the potential reduction of episcleral fibrosis at the surgical bleb site utilizing 0.3 mls of: balanced salt solution (n = 11); an inert gel delivery vehicle (n = 13); the gel delivery vehicle with incorporated recombinant tissue plasminogen activator (tpa; n = 14), 1 mg/ml. Statistical analysis of computer assisted area measurements from multiple histologic sections demonstrated a significant decrease in episcleral fibrosis in the t-PA group as compared to the two other groups (p less than 0.05). Results from the t-PA group did not demonstrate an effect on intraocular pressure. There was no clinical evidence of toxicity or healing complications in the t-PA group.