Analysis: Baerveldt implant reduces IOP more than Ahmed glaucoma valve
CORONADO, Calif. — On average over time, the Baerveldt glaucoma implant reduced IOP significantly more than the Ahmed glaucoma valve but with more sight-threatening complications, Donald L. Budenz, MD, MPH, said at the American Glaucoma Society meeting.
Budenz presented a 5-year analysis of pooled data from the Ahmed Baerveldt Comparison Study and the Ahmed Versus Baerveldt Study, both randomized clinical trials.
Donald L. Budenz
“We chose to combine the similarly performed and designed ABC and AVB studies, combining their data rather than analyzing the results, and by combining the data between these two large prospective clinical trials, we’re better able to get estimates and smaller confidence intervals,” Budenz said.
The analysis looked at safety and efficacy of the Ahmed glaucoma valve model FP7 (New World Medical) and the Baerveldt model BG 101-350 (Abbott Medical Optics/Johnson & Johnson Vision) in 514 patients undergoing tube shunt placement as a planned surgical procedure. There were no statistically significant differences in baseline characteristics between the two groups.
“In this pooled data analysis, we found a large lowering of intraocular pressure over time with the two groups: in the Ahmed group, a near 50% reduction, and in the Baerveldt group, a near 60% reduction in IOP,” he said.
Primary failure criteria were IOP less than 6 mm Hg or greater than 18 mm Hg, the need for additional glaucoma surgery, removal of the implant or severe loss of vision. The study, published in American Journal of Ophthalmology, cites a 4.5% rate of hypotony in the Baerveldt group and a 0.4% rate in the Ahmed group (P = .02).
“Using this primary failure criteria, there was a failure rate of 49% in the Ahmed group and 37% in the Baerveldt group (P = .03),” Budenz said.
Final mean IOP at 5 years was 15.8 mm Hg in the Ahmed group and 13.2 mm Hg in the Baerveldt group, with the 2.6 mm Hg difference being “highly statistically significant” (P < .001), according to Budenz.
Mean medication use was less in the Baerveldt group as well at 5 years at 1.5 compared with 1.9 in the Ahmed group (P = .023).
There were, however, more sight-threatening complications and cases of hypotony with the Baerveldt implant, “although final visual acuity analysis was equal in the two groups,” Budenz said.
“This study has certainly changed my own practice, as I had primarily been a Baerveldt user prior to entering the study,” Budenz said. “Now I find it perfectly reasonable to use an Ahmed implant first in the majority of patients due to safety concerns raised by this study with the Baerveldt implant, realizing that I can always use a larger surface area implant going forward.” – by Patricia Nale, ELS
Budenz DL. Five-year pooled data analysis of the Ahmed Baerveldt Comparison Study and the Ahmed Versus Baerveldt Study. Presented at: American Glaucoma Society annual meeting; March 2-5, 2017; Coronado, Calif.
Christakis PG, et al. Am J Ophthalmol. 2017;doi:10.1016/j.ajo.2017.01.003.
Disclosure: Budenz reports no relevant financial disclosures. New World Medical and Abbott Medical Optics supported the study.