Study: Intracameral tPA clears glaucoma valve obstructions

CINCINNATI — Intracameral tissue plasminogen activator can help clear and prevent obstruction of valved glaucoma drainage implants, according to a retrospective study.

Alan Zalta, MD, and colleagues here at the University of Cincinnati College of Medicine retrospectively analyzed 620 Ahmed and Krupin valves implanted between December 1992 and May 2001. They identified 36 eyes treated with intracameral tPA for total or imminent tube obstruction by fibrin and/or blood. The mean follow-up was 2.5 years.

Intracameral tPA successfully cleared or prevented tube occlusion by fibrin or blood clots in 32 of the 36 eyes. Multiple tPA injections were administered in 39% of the eyes. The mean number of injections needed to achieve successful outcomes was 1.6. The mean tPA dose per injection was 9.8 µg, and the mean total tPA does required to achieve success was 15.5 µg.

For the 31 eyes with totally included tubes, the mean intraocular pressure reduction 24 hours after administration was 21 mm Hg.

Significant complications, including severe hyphema, profound hypotony and anterior chamber flattening, occurred after 10.9% of tPA administrations.

According to the authors, their study represents the largest experience to date with tPA use after glaucoma drainage implant surgery and the only case series of tPA use in valved implants.

The study is published in the November issue of Archives of Ophthalmology.