Risk factors for the hypertensive phase after implantation of a glaucoma drainage device

Abstract

Purpose: To investigate risk factors for the development of the hypertensive phase after implantation of the Ahmed glaucoma valve (AGV). Methods: A total of 128 patients who had undergone AGV implantation were included in this study. The hypertensive phase was defined as intraocular pressure (IOP) > 21 mmHg during the first 3 months after surgery. Failure was defined IOP > 21 mmHg or less than a 20% reduction from baseline on two consecutive study visits after 3 months. Results: Mean age and preoperative IOP were not different between the hypertensive and non-hypertensive groups (p = 0.054, 0.065, respectively). Axial length (AL) was significantly longer in the hypertensive group (25.2 ± 2.6 mm) than in the non-hypertensive group (23.6 ± 1.6 mm; p = 0.006). AL was correlated with postoperative IOP at 1 and 3 months postoperatively (r = 0.176, p = 0.047; r = 0.363, p < 0.001), but not at 6 months and 1 year postoperatively (p = 0.105, 0.068). Only AL was significantly associated with development of the hypertensive phase (p = 0.026) in the binary logistic regression analysis. The development of hypertensive phase was higher in the high-myopia group (95.1%) than in the non-high myopia group (79.3%; p = 0.011). The cumulative probability of success at postoperative 1 year was 96.5% in the non-high myopia group and 95.1% in the high myopia group (p = 0.784). Conclusions: Eyes with high myopia were at the greatest risk for developing hypertension following implantation of a glaucoma drainage valve.