PRESERFLO MicroShunt Implantation as a Repeat Surgery after Failed Ab Interno XEN45 Gel Stent Implantation: A Case-Matched Study

Purpose: To investigate through a case-matched analysis whether failed ab interno XEN45 Gel Stent implantation exerts an influence on the outcome after subsequent implantation of a Preserflo MicroShunt. Methods: In this retrospective study, 70 eyes from 70 participants who underwent Preserflo MicroShunt implantation were included. Thirty-five eyes each underwent primary stent implantation (control group) or had previously undergone failed XEN45 Gel Stent implantation (post-XEN group). The two groups were matched at a 1:1 ratio based on the following criteria: preoperative and maximum intraocular pressure (IOP), preoperative medication score, cup/disc-ratio, follow-up time, and age. Surgery was defined as either “success” or “failure” based on the following three scores: an IOP reduction of >20% and IOP at the longest follow-up <21 mmHg (Score A) or <18 mmHg (Score B) or IOP ≤15 mmHg and an IOP reduction ≥40% (Score C). In all scores, revision surgery was considered a failure. Furthermore, we compared postoperative IOP and medication score, side effects, and revision rate between both groups. Results: Mean IOP decreased from 28.9 to 12.2 mmHg in the post-XEN group and from 27.7 to 12.9 mmHg in the control group, while the mean medication score decreased from 2.1 in the post-XEN group and from 2.6 in the control group to 0.3, respectively. Comparative analyses between the two groups did not reveal a significant difference in postoperative IOP, medication score, side effects, revision, or success rate. Conclusion: Preserflo MicroShunt implantation can be considered a viable option for repeat surgery in patients with bleb failure after prior XEN45 Gel Stent implantation.