Three-year clinical outcome of XEN45 Gel Stent implantation versus trabeculectomy in patients with open angle glaucoma

Abstract

Objective: To reliably compare the three-year clinical outcome and safety of XEN45 Gel Stent implantation (XEN) vs. trabeculectomy (TRAB) in patients with glaucoma.

Subject/methods: We conducted a retrospective cohort study with patients with primary open angle or pseudoexfoliation glaucoma with uncontrolled intraocular pressure (IOP) undergoing XEN or TRAB at the Innsbruck University Clinic of Ophthalmology and Optometry, Austria and analysed changes in IOP, numbers of IOP-lowering medications, and complete surgical success (i.e., IOP ≤ 18 mmHg, ≥20% IOP reduction and not requiring IOP-lowering medication) up to 36 months postoperatively.

Results: Between 2013 and 2019, we performed XEN Gel Stent implantation in 58 eyes and trabeculectomy in 84 eyes. From baseline to 36 months, mean IOP decreased from 23.4 to 13.8 mmHg (mean reduction 35%, 95% confidence interval 23-48%, p < 0.001) in the XEN group and from 25.1 to 11.2 mmHg (mean reduction 50%, 41-60%, p < 0.001) in the TRAB group. TRAB provided higher IOP reduction than XEN Gel Stent implantation at 12, 24, and 36 months (all p < 0.05). In XEN versus TRAB, IOP-lowering medication was required by 98.3% vs. 97.6% before surgery (p = 0.781), differed significantly at month 12 (43.2% vs. 2.0%, p < 0.001)but not at month 24 or 36. Complete surgical success was achieved in 40.0% vs. 62.8% at month 24 (adjusted odds ratio 2.70; 1.04-7.00, p = 0.040) and 27.3% vs. 56.8% at month 36 (4.36; 1.25-15.18, p = 0.021).

Conclusion: Compared to XEN, TRAB was associated with lower intraocular pressure, less IOP-lowering medication, and higher probability of achieving complete surgical success over a 36-month follow-up period.

Fig. 1. Intraocular pressure (Panel A), within-person percentage reduction compared to the preoperative value (Panel B) in the XEN Gel Stent implantation group and the trabeculectomy group over the 36-month follow-up and adjusted* mean differences in intraocular pressure achieved by XEN vs. TRAB estimated using a linear mixed model that incorporates all repeated measurements during follow-up (Panel C).

CI confidence interval, TRAB trabeculectomy, XEN XEN Gel Stent. *The linear mixed model was adjusted for age, sex, number of pre-operative IOP-lowering medications, and phacoemulsification and included a random intercept allowed to vary at the patient and the eye level.

Fig. 2. Number of intraocular pressure-lowering medications taken during follow-up.

IOP intraocular pressure, TRAB trabeculectomy, XEN XEN Gel Stent.

Fig. 3. Kaplan-Meier curves showing the proportion free of needling, bleb revision, and surgical failure after XEN Gel Stent implantation or trabeculectomy.

The hazard ratios presented in the subtitles were adjusted for age, sex, number of pre-operative IOP-lowering medications, and phacoemulsification. HR hazard ratio, TRAB trabeculectomy, XEN XEN Gel Stent.