Effect of Early Postoperative Aqueous Suppression Therapy on Surgical Outcomes of Valved Tube Shunts in Refractory Glaucoma

Abstract

Purpose : To compare the effect of early vs late treatment with aqueous suppressants on the surgical outcomes of Ahmed glaucoma valve (AGV) FP-7 implants

Methods : Retrospective comparative cohort study on refractory glaucoma patients who underwent AGV implantation at Wills Eye Hospital from 2016-2021 who received topical aqueous suppressants either in the first 2 weeks (group 1; early) or after 2 weeks (group 2; late) postoperatively. The main outcome measures were incidence of hypertensive phase (HP), defined as an intraocular pressure (IOP) of >21 mmHg within 3 postoperative months, surgical failure at months 6 and 12 (defined as IOP<5 or >21 mmHg), progression to no light perception (NLP) vision, or further glaucoma surgeries.

Results : 199 eyes of 194 patients (group 1=140, group 2=59) were included. Mean age was 68.2±15.8 years old. At baseline, visual acuity (VA) was 1.0±0.9 and 1.2±0.9 (P=0.083), IOP was 36.8±10.7 mmHg and 35.6±11.8 mmHg (P=0.485), and number of glaucoma medications was 2.9±1.4 and 3.0±1.6 (P=0.629), in groups 1 and 2 respectively. 43% of patients had primary open angle glaucoma and 52.7% had severe disease. HP developed in 35.7% of group 1 eyes and 50.8% of group 2 eyes (P=0.011). At month 6 (n=177) the surgical failure rate was similar in both groups (22.8% vs 20.0%, P=0.748). At month 12, (n=137) failure was also similar between groups (25.3% vs 39.5%, P=0.238). Reasons for failure were similar (P=0.055) and included IOP>21 mmHg (45.5%), further glaucoma surgeries (38.6%), and NLP vision (9.1%). Kaplan-Meier survival analysis comparing cumulative probability of failure at 12 months showed no significant difference between groups (P=0.461). Multivariate logistic regression analysis suggests that development of HP was a significant predictor of month 12 failure (P=0.044). Age, sex, race, late use of aqueous suppressants, glaucoma type and severity, baseline VA, IOP, narrow angle, and medication number were not significant predictors of failure.

Conclusions : Our findings suggest that early aqueous suppressant use after FP-7 AGV implantation was associated with decreased occurrence of a HP. Although surgical failure rate was similar between groups, HP was a significant predictor of month 12 failure. Longer-term follow-up with larger sample size studies are warranted on this subject.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.