One-year surgical outcomes of the PreserFlo MicroShunt in glaucoma: a multicentre analysis

Abstract

Background/aims: To evaluate the efficacy and safety of the PreserFlo MicroShunt glaucoma device in a multicentre cohort study.

Methods: All consecutive patients who received the microshunt with mitomycin-C (MMC) 0.4 mg/mL from May 2019 to September 2020 in three UK tertiary centres. Primary outcome at 1 year was a complete success, with failure defined as intraocular pressure (IOP) >21 mmHg or <20% reduction, IOP≤5 mmHg with any decreased vision on two consecutive visits, reoperation or loss of light perception vision. Secondary outcomes were IOP, best-corrected visual acuity, medications, complications, interventions and reoperations. We also performed subgroup analyses for severe glaucoma and assessed risk factors for failure.

Results: 104 eyes had 1-year follow-up. Complete and qualified success at 1 year were achieved in 51.9% (N=54) and 16.4% (N=17), respectively, and failure occurred in 31.7% (N=33). There was a significant reduction in IOP (mmHg) from preoperatively (23.4±0.8, N=104) to 12 months (14.7±0.6, N=104) (p<0.0001). Antiglaucoma medications also decreased from preoperatively (3.4±0.1, N=104) to 12 months (0.7±0.1, N=104) (p<0.0001). Multivariate analyses showed an association between higher mean deviation and failure (HR 1.055, 95% CI 1.0075 to 1.11, p=0.0227). Complications were hypotony (19.2%; N=20), choroidal detachments (10.6%; N=11), hyphaema (5.8%; N=6) and bleb leak (5.8%; N=6). Needling and 5-fluorouracil injections were performed in 12.5% (N=13) and 33.7% (N=35), respectively, and 11.5% (N=12) required revision surgery.

Conclusion: The PreserFlo MicroShunt with MMC 0.4 mg/mL showed an overall success rate of 68.3% at 1 year, and led to significant IOP and medication reduction with a low rate of adverse effects.

Keywords: Glaucoma; Intraocular pressure; Treatment Surgery; Wound healing.

Figure 1

Kaplan-Meier survival curves over 12 months for complete success (CS) and combined CS and qualified success (CS & QS) for: (A) IOP 6–21 mmHg; (B) IOP 6–17 mmHg; (C) IOP 6–14 mmHg. (D) Preoperative and postoperative IOP over 12 months. Box and whisker plot with line joining the mean at each time point. The middle line indicates the median, the lower and upper ends of boxes indicate the 5–95 percentiles. (E) Preoperative and postoperative logMAR best-corrected visual acuity over 12 months. (F) Postoperative change in the number of antiglaucoma medications over 12 months compared with preoperatively. 14 eyes of the 104 eyes that had 1 year follow-up data also had reoperations for glaucoma, and we censored the IOP, BCVA and medication data at the time of the second glaucoma operation. Mean±SEM. ***p<0.001. BCVA, best-corrected visual acuity; logMAR, Logarithm of the Minimum Angle of Resolution; IOP, intraocular pressure; ns, not significant; POD, postoperative day; POW, postoperative week; POM, postoperative month.

Figure 2

(A) HRs with 95% CI and p values for various factors potentially associated with failure: ethnicity, mitomycin-C treatment time (minutes), baseline best-corrected visual acuity (VA), side of operated eye, number of preoperative antiglaucoma drugs, lens status, preoperative cup-disc ratio, preoperative mean deviation (MD), type of glaucoma (POAG, PACG, secondary OAG, secondary ACG), preoperative IOP (mmHg), gender, age. (B) Kaplan-Meier survival curves over 12 months according to the severity of glaucoma: mild (MD≥6 dB), moderate (MD = −6 to −12 dB), severe/advanced severity (MD ≤12 dB). (C) Box and whisker plots showing distribution of MD for the mild, moderate and severe/advanced glaucoma groups. IOP, intraocular pressure; POAG, primary open angle glaucoma; PACG, primary angle closure glaucoma; SACG, secondary angle closure glaucoma; Secondary OAG, secondary open angle glaucoma.