The Ahmed Versus Baerveldt Study: 5-Year Outcomes
Ophthalmology, October 2016
In an international multicenter randomized trial, Christakis et al. compared 2 frequently used aqueous shunts in adult patients whose glaucoma was not controlled by medical therapy or who were at high risk of trabeculectomy failure. They found that both the Ahmed and Baerveldt devices reduced intraocular pressure (IOP) and need for medication.
A total of 238 patients were randomized to receive either an Ahmed-FP7 valve implant (n = 124) or a Baerveldt-350 implant (n = 114). The primary outcome measure was failure, defined as IOP outside the target range (5-18 mm Hg) or reduction of <20% from baseline at 2 consecutive visits after 3 months; severe vision loss; or de novo glaucoma surgery. Secondary outcome measures included IOP, medication use, visual acuity, complications, and interventions.
Baseline characteristics were similar between the 2 device groups. Mean preoperative IOP was 31.4 ± 10.8 mm Hg on 3.1 ± 1.0 glaucoma medications. At 5 years, the cumulative failure rate was 53% in the Ahmed group and 40% in the Baerveldt group (p = .04).
In both groups, the main reason for failure was high IOP. The cumulative de novo glaucoma reoperation rate was 18% in the Ahmed group and 11% in the Baerveldt group (p = .22). Hypotony resulted in failure in 5 patients (4%) in the Baerveldt group compared with none in the Ahmed group (p = .02). Mean IOP was 16.6 ± 5.9 mm Hg in the Ahmed group (47% reduction) and 13.6 ± 5.0 mm Hg in the Baerveldt group (57% reduction, p = .001).
Mean medication use was 1.8 ± 1.5 medications in the Ahmed group (44% reduction) and 1.2 ± 1.3 in the Baerveldt group (61% reduction; p = .03). The 2 groups had similar complication rates (Ahmed, 63%; Baerveldt, 69%) and intervention rates (Ahmed, 41%; Baerveldt, 41%). Most complications were transient, and most interventions were slit-lamp procedures.
The authors concluded that both implants were effective in reducing IOP and the need for glaucoma medications. The Baerveldt group had a lower failure rate and a lower IOP on fewer medications, but there was also a small risk of hypotony, which was not seen in the Ahmed group.
The original article can be found here.