Risk factors for hypertensive phase after Ahmed glaucoma valve implantation

Purpose To investigate the risk factors and the clinical characteristics of the hypertensive phase (HP) after Ahmed glaucoma valve (AGV) implantation. Methods This retrospective study included 60 eyes of 57 patients who underwent AGV implantation and with at least 1-year follow-up. HP was defined as intraocular pressure (IOP) > 21 mmHg in the first 3 months after the surgery. Independent samples t-test and Chi-square test were used to compare differences in patients with the HP and the non-HP groups. Univariable and multivariable logistic regression analyses were used to determine the risk factors for the development of the HP. Statistical significance was assumed at p < 0.05 level. Results HP was observed in 31 eyes (51.7%) with an average peak IOP of 27.6 +/- 4.5 mmHg (range 22-40 mmHg). The resolution of HP was noted in 27 eyes (87.1%) at the 3rd month postoperative visit. The number of glaucoma medications at the last postoperative visit and IOP values from 1 month to 1 year were significantly higher in the HP group (all p < 0.05). Patients with traumatic glaucoma showed the highest rate (83.3%) of HP development. In the multivariable analysis, a preoperative IOP > 30 mmHg (p = 0.03, OR:5.82; reference: <= 25 mmHg) and younger age (41-64 years, p = 0.02, OR:8.49; <= 40 years, p = 0.001, OR:19.62; reference: >= 65 years) were independently associated with the occurrence of HP. Conclusion Hypertensive phase was observed in half of the patients undergoing AGV implantation. A higher mean preoperative IOP and younger age were risk factors for HP development. Although the majority resolved at the 3-month visit, eyes with HP had higher mean IOPs and required more IOP lowering medications.