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.