The Ahmed Baerveldt Comparison Study Methodology, Baseline Patient Characteristics, and Intraoperative Complications

Purpose: The Ahmed Baerveldt Comparison (ABC) Study compares the long-term outcomes and complications of the Ahmed glaucoma valve (AGV; model FP7; New World Medical, Los Ranchos, CA) and the Baerveldt glaucoma implant (BGI; model 101-350; Abbott Medical Optics, Abbott Park, IL). Design: Multicenter, randomized, controlled clinical trial. Participants: Two hundred seventy-six glaucoma patients at 16 clinical centers worldwide who were 18 to 85 years of age with inadequately controlled intraocular pressure (IOP; >= 18 mmHg) in whom placement of an aqueous shunt was planned. Methods: Study patients were randomized to undergo implantation of an AGV or a BGI. Main Outcome Measures: Failure, defined as IOP > 21 mmHg or not reduced by 20% less than baseline or IOP <= 5 mmHg (2 consecutive visits after 3 months), additional glaucoma surgery, removal of the implant, or loss of light perception vision. Results: A total of 276 patients were enrolled between October 2006 and April 2008, including 143 in the AGV group and 133 in the BGI group. The mean age +/- standard deviation (SD) of patients enrolled was 63 +/- 14 years, and 52% were male. The mean baseline IOP +/- SD was 31.5 +/- 11.8 mmHg. Except for a 13% higher prevalence of hypertension in the AGV group, no significant differences in baseline demographic or ocular characteristics were observed between the study groups. Intraoperative complications occurred in 11 (8%) patients in the AGV group and in 16 (12%) patients in the BGI group (P = 0.31). Conclusions: The ABC Study should yield valuable prospective data comparing 2 commonly used aqueous shunts in clinical practice.