Three-year treatment outcomes in the Ahmed Baerveldt comparison study

Abstract

Purpose: To compare 3-year outcomes and complications of the Ahmed FP7 Glaucoma Valve (AGV) (New World Medical, Cucamonga, CA) and the Baerveldt Glaucoma Implant (BGI) 101-350 (Abbott Medical Optics, Abbott Park, IL) for the treatment of refractory glaucoma.

Design: Multicenter, randomized, controlled clinical trial.

Participants: A total of 276 patients: 143 in the AGV group and 133 in the BGI group.

Methods: Patients aged 18 to 85 years with refractory glaucoma and intraocular pressures (IOPs) ≥ 18 mmHg in whom an aqueous shunt was planned were randomized to an AGV or a BGI.

Main outcome measures: The IOP, visual acuity (VA), supplemental medical therapy, complications, and failure (IOP >21 mmHg or not reduced by 20% from baseline, IOP <5 mmHg, reoperation for glaucoma or removal of implant, or loss of light perception vision).

Results: At 3 years, IOP (mean ± standard deviation) was 14.3 ± ± 4.7 mmHg (AGV group) and 13.1 ± 4.5 mmHg (BGI group) (P = 0.086) on 2.0 ± 1.4 and 1.5 ± 1.4 glaucoma medications, respectively (P = 0.020). The cumulative probabilities of failure were 31.3% (standard error [SE], 4.0%) (AGV) and 32.3% (4.2%) (BGI) (P = 0.99). Postoperative complications associated with reoperation or vision loss of >2 Snellen lines occurred in 24 patients (22%) (AGV) and 38 patients (36%) (BGI) (P = 0.035). The mean change in the logarithm of the minimum angle of resolution VA at 3 years was similar (AGV: 0.21 ± 0.88, BGI: 0.26 ± 0.74) in the 2 treatment groups at 3 years (P = 0.66). The cumulative proportion of patients (SE) undergoing reoperation for glaucoma before the 3-year postoperative time point was 14.5% (3.0%) in the AGV group compared with 7.6% (2.4%) in the BGI group (P = 0.053, log rank). The relative risk of reoperation for glaucoma in the AGV group was 2.1 times that of the BGI group (95% confidence interval, 1.0-4.8; P = 0.045, Cox proportional hazards regression).

Conclusions: Implantation of the AGV was associated with the need for significantly greater adjunctive medication to achieve equal success relative to implantation of the BGI and resulted in a greater relative risk of reoperation for glaucoma. More subjects experienced serious postoperative complications in the BGI group than in the AGV group.

Figure 1. Study Flow Diagram

Recruitument and retention in the ABC study at three years.

Figure 2. Intraocular Pressure (IOP) by randomized treatment group and follow-up visit

Graph of IOP (mmHg) in the Ahmed Baerveldt Comparison (ABC) Study by study group from preoperative level to last follow-up (mean ± standard deviation (SD))

Figure 3. Medication use by randomized treatment group and follow-up visit

Histogram of the number of classes of ocular hypotensive medication used from before surgery to three year follow-up visit (mean ± standard deviation (SD))

Figure 4. Kaplan-Meier cumulative surgical failure rates by randomized treatment group

Kaplan-Meier survival curve of cumulative surgical failures over three years of follow-up by treatment group.

Figure 5. Kaplan-Meier cumulative reoperation rates by randomized treatment group

Kaplan-Meier survival curve of cumulative reoperation rates by randomized treatment group in the first three years of follow-up.