Ahmed vs. Baerveldt Implants for Glaucoma: 5-Year Pooled Analysis
American Journal of Ophthalmology, April 2017
Christakis et al. conducted a pooled analysis of 2 randomized clinical studies to compare efficacy of the Ahmed-FP7 and Baerveldt BG101-350 glaucoma drainage devices. The authors found that the Baerveldt implant was less likely to fail over 5 years and was associated with decreases in mean intraocular pressure (IOP), rate of glaucoma surgery, and number of glaucoma medications required. However, the risk of hypotony was lower with the Ahmed device.
The authors examined data for 514 patients with advanced, uncontrolled glaucoma (trabeculectomy had failed or was at high risk of failing) who had been randomized to receive the Ahmed or the Baerveldt device. Outcome measures included cumulative rate of device failure (based on target IOP of 6-18 mm Hg), rate of de novo glaucoma surgery, mean IOP, mean number of glaucoma medications, and visual acuity.
Preoperatively, mean IOP was 31.2 mm Hg in the Ahmed group and 31.8 in the Baerveldt group. Five years postoperatively, mean IOP was 15.8 mm Hg for patients with the Ahmed device and 13.2 mm Hg for those with the Baerveldt device (p < .001). The average number of glaucoma medications was 1.9 in the Ahmed group and 1.5 in the Baerveldt group (p = .007).
The 5-year cumulative failure rate was higher for patients with the Ahmed implant (49% vs. 37% for Baerveldt implant; p = .007). In both groups, most device failures were ascribed to elevated IOP, but failure due to hypotony was more common in the Baerveldt group (4.5% vs. 0.4% for Ahmed group; p = .002). De novo glaucoma surgery was more common among patients who received the Ahmed implant (16% vs. 8% for Baerveldt implant; p = .006). Visual acuity was similar for the study groups and declined significantly over 5 years.
The authors concluded that the Baerveldt device appears superior in terms of efficacy outcomes, but it poses a higher risk of hypotony than the Ahmed implant. An analysis of risk factors for treatment failure is forthcoming, which may help to guide selection of the most appropriate drainage device for each patient.
The original article can be found here.