Safety outcomes of MicroShunt implantation versus trabeculectomy in patients with primary open-angle glaucoma

Authors: Marlene R. Moster¹, Isabelle Riss², Henny J. M. Beckers³.
¹Wills Eye Hospital, ²Pôle Ophtalmologique de la Clinique Mutualiste, ³University Eye Clinic, Maastricht University Medical Center.

Author Disclosure Block:M.R. Moster: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Alcon, Allergan, Qura, Santen. Any direct financial payments including receipt of honoraria; Description of relationship(s); Consultant/advisor, Consultant/advisor, Consultant/advisor, Consultant/advisor, Consultant/advisor. Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Alcon, Allergan, Bausch + Lomb, IRIDEX, MedEdicus, Novartis. Membership on advisory boards or speakers’ bureaus; Description of relationship(s); Lecture fees, Lecture fees, Lecture fees, Lecture fees, Lecture fees, Lecture fees, Lecture fees. Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Alcon, Allergan, Bausch + Lomb, Glaukos, InnFocus, IRIDEX. Funded grants or clinical trials; Description of relationship(s); Grant support, Grant support, Grant support, Grant support, Grant support, Grant support, Grant support. All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Name of for-profit or not-for-profit organization(s); Qura. All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Description of relationship(s); Equity/owner. I. Riss: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Santen. Any direct financial payments including receipt of honoraria; Description of relationship(s); Consultant. H.J.M. Beckers: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Santen, Glaukos. Any direct financial payments including receipt of honoraria; Description of relationship(s); Consultant, speaker, Consultant, speaker. Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Santen. Membership on advisory boards or speakers’ bureaus; Description of relationship(s); Advisory board (Asia). Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); InnFocus Inc, a Santen company. Funded grants or clinical trials; Description of relationship(s); Funding research.

Abstract Body:

Purpose: The MicroShunt is a controlled micro-incisional ab-externo glaucoma filtration surgery device that aims to reduce intraocular pressure (IOP) by draining aqueous humour from the anterior chamber to a bleb under the conjunctiva and Tenon’s capsule. This analysis reports 1-year safety outcomes following MicroShunt surgery or trabeculectomy.
Study Design: A 2-year prospective, randomized, single-masked, multicentre study (NCT01881425) assessed the effectiveness and safety of standalone MicroShunt surgery versus trabeculectomy in patients with primary open-angle glaucoma.
Methods: Patients aged 40 to 85 years with uncontrolled IOP (≥15 to ≤40 mmHg) on maximum tolerated glaucoma medication were randomized in a 3:1 ratio to MicroShunt surgery or trabeculectomy, both performed with intraoperative Mitomycin C (0.2 mg/mL applied via sponges for 2 minutes). Safety outcomes at Year 1 included adverse events (AEs), needlings, bleb revisions and reoperations.
Results: In total, 395 eyes underwent MicroShunt surgery and 131 eyes underwent trabeculectomy. Of the reported postoperative AEs, most occurred between Day 1 and Month 1 (64.6% MicroShunt vs 84.7% trabeculectomy; P<0.001). Most common early AEs (on or before Month 3) were hypotony (IOP <6 mmHg at any time; 26.3% vs 48.1%; P<0.001) and increased IOP requiring treatment (25.3% MicroShunt vs 49.6% trabeculectomy; P<0.001). Most common late AEs (after Month 3) were increased IOP requiring treatment (32.9% vs 13.7%; P<0.001) and confirmed worsening in visual field of ≥2.5 dB (10.4% vs 15.3%; P=0.982). Needling rates by Year 1 were 19.0% (MicroShunt) and 8.4% (trabeculectomy; P=0.005); response rates (RR; post-event IOP lower than pre-event IOP with no secondary intervention [eg revision, surgery, needling] within 3 months) were 45.3% and 72.7%, respectively. Bleb revision rates by Year 1 were 5.8% (MicroShunt) and 6.9% (trabeculectomy; P=0.664); RRs were 56.5% and 44.4%, respectively. Glaucoma reoperations up to Year 1 included placement of a glaucoma drainage device (4.8% MicroShunt vs 2.3% trabeculectomy; P=0.265) and secondary trabeculectomy (2.8% vs 0.8%; P=0.265).
Conclusions: In this study, MicroShunt surgery was associated with significantly fewer AEs compared with trabeculectomy in the first postoperative month. Significantly lower rates of hypotony and increased IOP requiring treatment were reported in the MicroShunt group versus the trabeculectomy group within the first 3 months following surgery. After Month 3, trabeculectomy had a significantly lower rate of increased IOP requiring treatment compared with the MicroShunt group. Few needlings, bleb revisions and glaucoma reoperations were required post surgery following both treatments.