Recombinant hirudin prevents postoperative fibrin formation after experimental cataract surgery

Purpose: The authors studied the effect of a direct acting antithrombin agent, desulfatohirudin variant I (Revasc, Ciba-Geigy, Ltd., Basel, Switzerland), on postoperative fibrin formation after cataract surgery in rabbits. Methods: Phacoemulsification was performed in a masked fashion on 28 eyes of 28 New Zealand white rabbits. Ten control group eyes had lactated Ringer's solution in the infusion and an intracameral injection (similar to 1.5 ml) at the end of the case. Ten group I eyes received hirudin 100 mu g/ml in the infusion and intracameral injection. Eight group 2 eyes had 100 mu g/ml hirudin in the intracameral injection only. Using slit-lamp examination, all eyes were graded for the amount of fibrin and intraocular hemorrhage in a masked fashion on postoperative day 1. Results: Comparison of the mean postoperative fibrin grade (0-4) in group 1 (mean = 0.3), group 2 (mean = 0.25) and the control group (mean = 3.4) revealed a statistically significant difference between hirudin-treated and control eyes (P = 0.0002 for group 1, P = 0.0005 for group 2). No intraocular hemorrhage was noted in any group. Conclusions: Recombinant hirudin significantly decreases postoperative fibrin formation in a rabbit cataract extraction model. Intracameral injection of hirudin alone appears to be at least as effective as infusion of hirudin throughout the case. With further study, this agent has potential for use in cataract surgery on patients known to be at high risk for postoperative fibrin formation.