Efficacy and Adverse Event Profile of the iStent and iStent Inject Trabecular Micro-bypass for Open-angle Glaucoma: A Meta-analysis

Abstract

AimThis meta-analysis explores the efficacy and adverse event profile of the iStent, an ab interno implant for the treatment of open-angle glaucoma.MethodsA systematic literature search of Ovid MEDLINE and EMBASE was used to identify peer-reviewed original studies that provided efficacy data on the first or second generation iStent for at least five eyes. Intraocular pressure (IOP) was the primary efficacy endpoint, while the number of medication classes was the secondary outcome. Weighted mean differences were reported for continuous endpoints, while a relative risk was computed for dichotomous variables.Review ResultsThe search revealed 545 results, of which 1767 eyes from 28 studies were included. The cohort age was 71.4 ± 5.4 years, and 44.9% of patients were male. There was a significantly greater IOP reduction after the use of two first-generation stents compared to one, irrespective of phacoemulsification status (p < 0.001). Additionally, there was a significantly greater IOP reduction following iStent alone relative to phaco-iStent for the first-generation iStent (p < 0.001) and the iStent inject (p < 0.001). For the first generation stent, combined phaco-iStent provided a greater level of IOP reduction (p < 0.001) and reduction in the number of medication classes relative to phacoemulsification alone (p < 0.001). In total, 22.5% of eyes that received iStent implantation sustained some type of adverse event. The most common adverse events were intraocular pressure elevation, stent blockage or obstruction, stent malposition and hyphema.Conclusion and Clinical SignificanceStatistically significant differences in efficacy outcomes exist between different numbers of stents and the presence or absence of concurrent phacoemulsification.How to cite this article: Popovic M, Campos-Moller X, Saheb H, Ahmed IIK. Efficacy and Adverse Event Profile of the iStent and iStent Inject Trabecular Micro-bypass for Open-angle Glaucoma: A Meta-analysis. J Curr Glaucoma Pract 2018;12(2):67-84.

Second-Generation Trabecular Micro-Bypass Stents as Standalone Treatment for Glaucoma: A 36-Month Prospective Study

“…It is noteworthy that iStent inject had a positive effect in these formerly treatment-resistant eyes. This treatment effect is consistent with prior studies showing benefit of this technology in various stages of glaucoma, from mild to advanced [40][41][42][43][44][45][46][47][48][49][50][51]. It also suggests that iStent inject may have a viable role in settings different from those typically considered for MIGS procedures: specifically, it may be considered not just in mild-to-moderate glaucoma as a primary surgery, but also in refractory eyes that have progressed despite previously undergoing more invasive surgery.…”

“…1-2). In studies both with and without cataract surgery, and in both investigational and real-world settings, the ab interno-implanted iStent inject has demonstrated clinically significant reductions in IOP and medications over the long term [40][41][42][43][44][45][46][47][48][49][50][51]. These performance outcomes have been accompanied by favorable safety and a correspondingly advantageous benefit-to-risk profile.…”

What is the role of iStent in glaucoma management in 2019?

“…The effect size reported by Hooshmand et al is smaller than reported separately for the phaco‐iStent or phaco‐iStent inject . This may reflect a “real‐world” setting compared to that of a clinical trial—for example, pre‐ and post‐operative drop washout periods were not included.…”

“…The quality of evidence continues to improve, with a recent publication of meta‐analyses of the first‐generation iStent—both combined with phacoemulsification and as stand‐alone surgery—and a 2‐year prospective randomized control trial of the second‐generation iStent inject . The safety of these devices is well‐established in the short term—the most common adverse events are transient hyphema, stent malposition or blockage—and long‐term data are awaited.…”

“…One of the main questions regarding the efficacy of the iStent is: What is the additional effect of the device in a combined surgery compared to cataract surgery alone? A meta‐analysis of 1767 eyes from 28 studies has shown significantly greater reduction in intraocular pressure (IOP) (6.30 compared to 4.62 mmHg reduction, weighted mean difference [WMD] 1.68 mmHg and 95% confidence interval [CI] 1.11‐2.25 mmHg) and a greater reduction in number of glaucoma drops (−1.4 drops compared to −0.6 drops, WMD 0.80, 95% CI 0.75‐0.85) after phaco‐iStent compared to phacoemulsification alone . More recently, a large randomized trial of 500 eyes showed that 63.2% of eyes undergoing phacoemulsification plus iStent inject achieved an IOP ≤18 mmHg off all medications compared to only 50% undergoing phacoemulsification alone at 2 years .…”