Three-Year Treatment Outcomes in the Ahmed Baerveldt Comparison Study
The authors of the following multicenter, randomized, controlled clinical trial compared three-year outcomes and complications of the Ahmed FP7 Glaucoma Valve (AGV) (New World Medical) and the Baerveldt Glaucoma Implant (BGI) 101-350 (Abbott Medical Optics) for the treatment of refractory glaucoma.
Participants consisted of 276 patients: 143 in the AGV group and 133 in the BGI group. The authors randomized patients aged 18 to 85 years with refractory glaucoma and intraocular pressures ≥18 mmHg in whom an aqueous shunt was planned to an AGV or a BGI. Main outcome measures were IOP, visual acuity, 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).
At three years, the authors noted that IOP (mean ± standard deviation) was 14.3 ± 4.7 mmHg in the AGV group and 13.1 ± 4.5 mmHg in the BGI group (p=0.086) on 2.0 ± 1.4 and 1.5 ± 1.4 glaucoma medications, respectively (p=0.020). The also reported that the cumulative probabilities of failure were 31.3% (standard error, 4.0%) in the AGV group and 32.3% (4.2%) in the BGI group (p=0.99). Postoperative complications associated with reoperation or vision loss of more than two 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 three years was similar (AGV: 0.21 ± 0.88, BGI: 0.26 ± 0.74) in the two treatment groups at three years (p=0.66). Furthermore, the cumulative proportion of patients (SE) undergoing reoperation for glaucoma before the three-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).
To conclude, 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.