Midterm Survival Results of Preserflo® in a Real-world Setting: A Retrospective 2-year Analysis.

Prcis: Preserflo® surgery is a safe procedure, effective in reducing intraocular pressure into the "low teens", surgical survival is greatest in cases of high baseline intraocular pressure (above 21 mmHg) and when performed as a standalone procedure.

Purpose: To evaluate midterm surgical survival and safety profile of Preserflo® filtering surgery.

Methods: Retrospective, cohort study. Consecutive patients who underwent standardized Preserflo® implantation with mitomycin C from December 2019 to April 2021 were included. Clinical data was retrieved from patient charts. Primary outcome was surgical survival at twenty-four months in accordance with World Glaucoma Association guidelines. Survival was evaluated using Kaplan-Meier statistics. Analysis was performed at eye-level and as intention-to-treat.

Results: Ninety-five eyes were included in this study (18 cases combined with cataract surgery). Over half of cases (n=51) were primary open angle glaucoma, with over a fifth having a prior filtering glaucoma procedure. Intraocular pressure at twenty-four months was significantly decreased from baseline (22.4±6.28 mmHg vs 12.0±3.43 mmHg), as well as the need for IOP-lowering medication (2.88 (±0.92) vs 0.79 (±1.3), P<0.001 all comparisons. Standalone Preserflo® achieved a qualified survival (irrespective of medication) of 71% (CI 95% 62%-83%) and 44% (CI 95% 27%-75%) in the combined procedure subgroup (P<0.05 when considering absolute survival). Eyes with baseline intraocular pressure ≥21 mmHg showed a greater qualified survival when compared to eyes with baseline ≤18 mmHg (80% (CI 95% 65%-100%) vs (50% (CI 95% 32%-76%; P<0.05). Intra and early operative complications were few, self-limited, and did not require surgical management. The reoperation rate was low (18%).

Conclusion: Preserflo ® filtering surgery is effective in reducing intraocular pressure into the "low teens" and presents an adequate surgical survival and safety profile. Surgical survival appears greatest when performed as standalone and when pre-operative intraocular pressure is high (≥21 mmHg).