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Meta-Analysis
. 2020 Mar 9;3(3):CD012740.
doi: 10.1002/14651858.CD012740.pub2.

Ab interno trabecular bypass surgery with Schlemm´s canal microstent (Hydrus) for open angle glaucoma

Francisco Otarola #  1   2 , Gianni Virgili #  3 , Anupa Shah  4 , Kuang Hu  1 , Catey Bunce  5 , Gus Gazzard  1   6
Affiliations
Meta-Analysis

Ab interno trabecular bypass surgery with Schlemm´s canal microstent (Hydrus) for open angle glaucoma

Francisco Otarola et al. Cochrane Database Syst Rev. .

Abstract

Background: Glaucoma is a leading cause of irreversible blindness. A number of minimally-invasive surgical techniques have been introduced as a treatment to prevent glaucoma from progressing; ab interno trabecular bypass surgery with the Schlemm's canal Hydrus microstent is one of them.

Objectives: To evaluate the efficacy and safety of ab interno trabecular bypass surgery with the Hydrus microstent in treating people with open angle glaucoma (OAG).

Search methods: On 7 May 2019, we searched CENTRAL (2019, Issue 5), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov; and the WHO ICTRP.

Selection criteria: We searched for randomised controlled trials (RCTs) of the Hydrus microstent, alone or with cataract surgery, compared to other surgical treatments (cataract surgery alone, other minimally-invasive glaucoma device techniques, trabeculectomy), laser treatment, or medical treatment.

Data collection and analysis: A minimum of three authors independently extracted data from reports of included studies, using a data collection form and analysed data, based on standard Cochrane methods.

Main results: We included three published studies, with 808 people randomised. Two studies had multiple international recruitment centres in the USA and other countries. The third study had several sites based in Europe. All three studies were sponsored by the Hydrus manufacturer Ivantis Inc. All studies included participants with mainly mild or moderate OAG (mean deviation between -3.6 dB (decibel) and -8.4 dB in all study arms), which was controlled with medication in many participants (mean medicated intraocular pressure (IOP) 17.9 mmHg to 19.1 mmHg). There were no concerns regarding allocation concealment bias, but masking of outcome assessors was high or unclear risk in all studies; masking of participants was achieved, and losses to follow-up were not a concern. Two studies compared the Hydrus microstent combined with cataract surgery to cataract surgery alone, in participants with visually significant cataracts and OAG. We found moderate-certainty evidence that adding the Hydrus microstent to cataract surgery increased the proportion of participants who were medication-free from about half to more than three quarters at 12-month, short-term follow-up (risk ratio (RR) 1.59, 95% confidence interval (CI) 1.39 to 1.83; 2 studies, 639 participants; I² = 0%; and 24-month, medium-term follow-up (RR 1.63, 95% CI 1.40 to 1.88; 2 studies, 619 participants; I² = 0%). The Hydrus microstent combined with cataract surgery reduced the medium-term mean change in unmedicated IOP (after washout) by 2 mmHg more compared to cataract surgery alone (mean difference (MD) -2.00, 95% CI -2.69 to -1.31; 2 studies, 619 participants; I² = 0%; moderate-certainty evidence), and the mean change in IOP-lowering drops (MD -0.41, 95% CI -0.56 to -0.27; 2 studies, 619 participants; I² = 0%; low-certainty evidence). We also found low-certainty evidence that adding a Hydrus microstent to cataract surgery reduced the need for secondary glaucoma surgery from about 2.5% to less than 1% (RR 0.17, 95% CI 0.03 to 0.86; 2 studies, 653 participants; I² = 27%; low-certainty evidence). Intraocular bleeding, loss of 2 or more visual acuity (VA) lines, and IOP spikes of 10 mmHg or more were rare in both groups; estimates were imprecise, and included both beneficial and harmful effects. There were no cases of endophthalmitis in either group. No data were available on the proportion of participants achieving IOP less than 21 mmHg, 17 mmHg, or 14 mmHg; health-related quality of life (HRQOL), or visual field progression. One study provided short-term data for the Hydrus microstent compared with the iStent trabecular micro-bypass stent (iStent: implantation of two devices in a single procedure) in 152 participants with OAG (148 in analyses). Use of the Hydrus increased the proportion of medication-free participants from about a quarter to about half compared to those who received iStent, but this estimate was imprecise (RR 1.94, 95% CI 1.21 to 3.11; low-certainty evidence). Use of the Hydrus microstent reduced unmedicated IOP (after washout) by about 3 mmHg more than the iStent (MD -3.10, 95% CI -4.17 to -2.03; moderate-certainty evidence), and the use of IOP-lowering medication (MD -0.60, 95% CI -0.99 to -0.21; low-certainty evidence). Both devices achieved a final IOP < 21 mmHg in most participants (Hydrus microstent: 91.8%; iStent: 84%; RR 1.09, 95% CI 0.97 to 1.23; low-certainty evidence). None of the participants who received the Hydrus microstent (N = 74) required additional glaucoma surgery; two participants who received the iStent (N = 76) did. Few adverse events were found in either group. No data were available on the proportion of participants achieving IOP less than 17 mmHg or 14 mmHg, or on HRQOL.

Authors' conclusions: In people with cataracts and generally mild to moderate OAG, there is moderate-certainty evidence that the Hydrus microstent with cataract surgery compared to cataract surgery alone, likely increases the proportion of participants who do not require IOP lowering medication, and may further reduce IOP at short- and medium-term follow-up. There is moderate-certainty evidence that the Hydrus microstent is probably more effective than the iStent in lowering IOP of people with OAG in the short-term. Few studies were available on the effects of the Hydrus microstent, therefore the results of this review may not be applicable to all people with OAG, particularly in selected people with medically uncontrolled glaucoma, since IOP was controlled with medication in many participants in the included studies. Complications may be rare using the Hydrus microstent, as well as the comparator iStent, but larger studies are needed to investigate its safety.

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Conflict of interest statement

FO has no conflict of interest to declare. GV has no conflict of interest to declare. AS has no conflict of interest to declare. KH performs minimally‐invasive glaucoma surgery. He has lectured on 'Constructing clinical trials for MIGS ‐ the lack of evidence and what to do about it' at the Moorfields International Glaucoma Symposium 2016, sponsored by Laboratoires Thea, which is contributing an educational grant to Moorfields Eye Hospital. CB has no conflict of interest to declare. GG: In the last five years, GG has received travel funding, and his host organisation has received both educational and unrestricted research funding from pharmaceutical and equipment manufacturers that are involved in the treatment of glaucoma, but none that are otherwise related to (or competing with) the subject of this review.

Figures

1
1
Study flow diagram
2
2
Risk of bias summary: review authors' judgements about each risk of bias item for each included study
3
3
Forest plot of comparison: 1 Cataract surgery with Hydrus microstent vs. cataract surgery (CS) alone, outcome: 1.1 Proportion drop‐free: short term
4
4
Forest plot of comparison: 1 Cataract surgery with Hydrus microstent vs cataract surgery (CS) alone, outcome: 1.2 Proportion drop‐free: medium term
5
5
Forest plot of comparison: 1 Cataract surgery with Hydrus microstent vs cataract surgery (CS) alone, outcome: 1.4 Mean change in IOP‐lowering drops taken per day: medium term
6
6
Forest plot of comparison: 1 Cataract surgery with Hydrus microstent vs cataract surgery (CS) alone, outcome: 1.3 Mean change in IOP measured using Goldmann applanation tonometry: medium term
1.1
1.1. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 1 Proportion drop‐free: short‐term (6 to 18 months).
1.2
1.2. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 2 Proportion drop‐free: medium‐term (18 to 36 months).
1.3
1.3. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 3 Mean change in IOP measured using Goldmann applanation tonometry: medium‐term (18 to 36 months).
1.4
1.4. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 4 Mean change in IOP‐lowering drops instilled per day: medium‐term (18 to 36 months).
1.5
1.5. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 5 Proportion of participants requiring additional glaucoma surgery or laser.
1.6
1.6. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 6 Adverse events: loss of 2+ VA lines.
1.7
1.7. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 7 Adverse events: IOP spike > 10 mmHg.
1.8
1.8. Analysis
Comparison 1 Cataract surgery + Hydrus microstent vs cataract surgery (CS) alone, Outcome 8 Adverse events: bleeding.
2.1
2.1. Analysis
Comparison 2 Hydrus microstent vs iStent trabecular micro‐bypass stent, Outcome 1 Proportion drop‐free: short‐term (6 to 18 months).
2.2
2.2. Analysis
Comparison 2 Hydrus microstent vs iStent trabecular micro‐bypass stent, Outcome 2 Mean change in IOP measured using Goldmann applanation tonometry: short‐term (6 to 18 months).
2.3
2.3. Analysis
Comparison 2 Hydrus microstent vs iStent trabecular micro‐bypass stent, Outcome 3 Mean change in IOP‐lowering drops instilled per day: short‐term (6 to 18 months).
2.4
2.4. Analysis
Comparison 2 Hydrus microstent vs iStent trabecular micro‐bypass stent, Outcome 4 Proportion of participants with IOP < 21 mmHg.
See this image and copyright information in PMC

Update of

References

References to studies included in this review

COMPARE 2019 {published data only}
    1. Ahmed IIK, Fea A, Au L, Ang RE, Harasymowycz P, Jampel H, et al. A prospective randomized trial comparing Hydrus and iStent micro‐invasive glaucoma surgery implants for standalone treatment of open‐angle glaucoma: the COMPARE Study. Ophthalmology 2019;18:S0161‐6420. - PubMed
HORIZON 2018 {published data only}
    1. Jones J, Koch DD, Vold S, McCabe C, Rhee D, Lewis R, et al. Results from the United States cohort of the HORIZON trial of a Schlemm canal microstent to reduce intraocular pressure in primary open‐angle glaucoma. Journal of Cataract and Refractive Surgery 2019;45(9):1305‐15. - PubMed
    1. Samuelson TW, Chang DF, Marquis R, Flowers B, Lim KS, Ahmed IIK, et al. A Schlemm canal microstent for intraocular pressure reduction in primary open‐angle glaucoma and cataract: the HORIZON study. Ophthalmology 2018;126(1):29‐37. - PubMed
Pfeiffer 2015 {published data only}
    1. Pfeiffer N, Garcia‐Feijoo J, Martinez‐de‐la‐Casa JM, Larrosa JM, Fea A, Lemij H, et al. A randomized trial of a Schlemm's canal microstent with phacoemulsification for reducing intraocular pressure in open‐angle glaucoma. Ophthalmology 2015;122(7):1283‐93. - PubMed

References to studies awaiting assessment

Altafini 2014 {published data only (unpublished sought but not used)}
    1. Altafini R, Fea AM, Morselli S, Grignolo FM. Comparison between endothelial cell loss after express implant and mics, phaco mics safe‐trabeculectomy and phaco with hydrus implant. Investigative Ophthalmology and Visual Science 2014; Vol. 55:ARVO E‐abstract 6127.

References to ongoing studies

NCT02024464 {published data only}
    1. NCT02024464. Comparing Hydrus microstent (TM) to the iStent for lowering IOP in glaucoma patients undergoing cataract surgery. clinicaltrials.gov/ct2/show/NCT02024464 (first received 20 December 2013).

Additional references

AGIS 2000
    1. AGIS. The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration. American Journal of Ophthalmology 2000;130(4):429‐40. - PubMed
Agrawal 2018
    1. Agrawal P, Bradshaw SE. Systematic literature review of clinical and economic outcomes of micro‐invasive glaucoma surgery (MIGS) in primary open‐angle glaucoma. Ophthalmology and Therapy 2018;7(1):49‐73. - PMC - PubMed
Altman 1996
    1. Altman DG, Bland JM. Detecting skewness from summary information. BMJ 1996;313(7066):1200. - PMC - PubMed
Burr 2007
    1. Burr JM, Mowatt G, Hernandez R, Siddiqui MA, Cook J, Lourenco T, et al. The clinical effectiveness and cost‐effectiveness of screening for open angle glaucoma: a systematic review and economic evaluation. Health Technology Assessment 2007;11(41):1‐190. - PubMed
CNTG Study Group 1998
    1. CNTG Study Group. Comparison of glaucomatous progression between untreated patients with normal‐tension glaucoma and patients with therapeutically reduced intraocular pressures. American Journal of Ophthalmology 1998;126(4):487‐97. - PubMed
Covidence [Computer program]
    1. Veritas Health Innovation. Covidence. Melbourne: Veritas Health Innovation, accessed prior to 9 September 2018.
Francis 2011
    1. Francis BA, Singh K, Lin SC, Hodapp E, Jampel HD, Samples JR, et al. Novel glaucoma procedures: a report by the American Academy of Ophthalmology. Ophthalmology 2011;118(7):1466‐80. - PubMed
Friedman 2009
    1. Friedman DS, Okeke CO, Jampel HD, Ying GS, Plyler RJ, Jiang Y, et al. Risk factors for poor adherence to eyedrops in electronically monitored patients with glaucoma. Ophthalmology 2009;116(6):1097‐105. - PubMed
Gedde 2012
    1. Gedde SJ, Herndon LW, Brandt JD, Budenz DL, Feuer WJ, Schiffman JC, et al. Postoperative complications in the Tube Versus Trabeculectomy (TVT) study during five years of follow‐up. American Journal of Ophthalmology 2012;153(5):804‐14. - PMC - PubMed
Glanville 2006
    1. Glanville JM, Lefebvre C, Miles JN, Camosso‐Stefinovic J. How to identify randomized controlled trials in MEDLINE: ten years on. Journal of the Medical Library Association 2006;94(2):130‐6. - PMC - PubMed
GRADEpro GDT [Computer program]
    1. McMaster University (developed by Evidence Prime). GRADEpro GDT. Version accessed prior to 24 April 2019. Hamilton (ON): McMaster University (developed by Evidence Prime).
Heijl 2002
    1. Heijl A, Leske MC, Bengtsson B, Hyman L, Bengtsson B, Hussein M, et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Archives of Ophthalmology 2002;120(10):1268‐79. - PubMed
Higgins 2017
    1. Higgins JPT, Altman DG, Sterne JAC, editor(s). Chapter 8: Assessing risk of bias in included studies. In: Higgins JP, Churchill R, Chandler J, Cumpston MS, editor(s), Cochrane Handbook for Systematic Reviews of Interventions version 5.2.0 (updated June 2017). The Cochrane Collaboration, 2017. Available from www.training.cochrane.org/handbook.
Hu 2016
    1. Hu K, Gazzard G, Bunce C, Wormald R. Ab interno trabecular bypass surgery with Trabectome for open angle glaucoma. Cochrane Database of Systematic Reviews 2016, Issue 8. [DOI: 10.1002/14651858.CD011693.pub2] - DOI - PMC - PubMed
Ismail 2015
    1. Ismail R, Azuara‐Blanco A, Ramsay CR. Outcome measures in glaucoma: a systematic review of Cochrane Reviews and protocols. Journal of Glaucoma 2015;24(7):533‐8. - PubMed
Ismail 2016
    1. Ismail R, Azuara‐Blanco A, Ramsay CR. Consensus on outcome measures for glaucoma effectiveness trials: results from a Delphi and nominal group technique approaches. Journal of Glaucoma 2016;25(6):539‐46. - PubMed
James Lind Alliance 2013
    1. James Lind Alliance Sight Loss, Vision Priority Setting Partnership. Setting priorities for eye research. www.jla.nihr.ac.uk › downloads › SLV‐PSP_Final_Report_v111 (accessed 15 November 2019).
Kass 2002
    1. Kass MA, Heuer DK, Higginbotham EJ, Johnson CA, Keltner JL, Miller JP, et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open‐angle glaucoma. Archives of Ophthalmology 2002;120(6):701‐13. - PubMed
King 2013
    1. King A, Azuara‐Blanco A, Tuulonen A. Glaucoma. BMJ 2013;346:f3518. - PubMed
King 2018
    1. King AJ, Shah A, Nikita E, Hu K, Mulvaney CA, Stead R, et al. Subconjunctival draining minimally‐invasive glaucoma devices for medically uncontrolled glaucoma. Cochrane Database of Systematic Reviews 2018, Issue 12. [DOI: 10.1002/14651858.CD012742.pub2] - DOI - PMC - PubMed
Kirwan 2013
    1. Kirwan JF, Lockwood AJ, Shah P, Macleod A, Broadway DC, King AJ, et al. Trabeculectomy in the 21st century: a multicenter analysis. Ophthalmology 2013;120(12):2532‐9. - PubMed
Lavia 2017
    1. Lavia C, Dallorto L, Maule M, Ceccarelli M, Fea AM. Minimally‐invasive glaucoma surgeries (MIGS) for open angle glaucoma: A systematic review and meta‐analysis. PLoS One 2017;8:e0183142. - PMC - PubMed
Le 2019
    1. Le JT, Bicket AK, Wang L, Li T. Ab interno trabecular bypass surgery with iStent for open‐angle glaucoma. Cochrane Database of Systematic Reviews 2019, Issue 3. [DOI: 10.1002/14651858.CD012743.pub2] - DOI - PMC - PubMed
Lichter 2001
    1. Lichter PR, Musch DC, Gillespie BW, Guire KE, Janz NK, Wren PA, et al. Interim clinical outcomes in the Collaborative Initial Glaucoma Treatment Study comparing initial treatment randomized to medications or surgery. Ophthalmology 2001;108(11):1943‐53. - PubMed
Mansberger 2012
    1. Mansberger SL, Gordon MO, Jampel H, Bhorade A, Brandt JD, Wilson B, et al. Reduction in intraocular pressure after cataract extraction: the Ocular Hypertension Treatment Study. Ophthalmology 2012;119(9):1826‐31. - PMC - PubMed
Okeke 2009
    1. Okeke CO, Quigley HA, Jampel HD, Ying GS, Plyler RJ, Jiang Y, et al. Adherence with topical glaucoma medication monitored electronically. The Travatan Dosing Aid study. Ophthalmology 2009;116(2):191‐9. - PubMed
Otarola 2019 [pers comm]
    1. Otarola F. How many Hydrus devises have been implanted worldwide? [personal communication] Data request for Cochrane Review. Email to: btrauthen@ivantisinc.com 14 September 2019.
Overby 2009
    1. Overby DR, Stamer WD, Johnson M. The changing paradigm of outflow resistance generation: towards synergistic models of the JCT and inner wall endothelium. Experimental Eye Research 2009;88(4):656‐70. - PMC - PubMed
Peters 2013
    1. Peters D, Bengtsson B, Heijl A. Lifetime risk of blindness in open‐angle glaucoma. American Journal of Ophthalmology 2013;156(4):724‐30. - PubMed
Piltz 2000
    1. Piltz J, Gross R, Shin DH, Beiser JA, Dorr DA, Kass MA, et al. Contralateral effect of topical beta‐adrenergic antagonists in initial one‐eyed trials in the ocular hypertension treatment study. American Journal of Ophthalmology 2000;130(4):441‐53. - PubMed
Quigley 2006
    1. Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. British Journal of Ophthalmology 2006;90(3):262‐7. - PMC - PubMed
Radcliffe 2010
    1. Radcliffe NM, Musch DC, Niziol LM, Liebmann JM, Ritch R, Collaborative Initial Glaucoma Treatment Study Group. The effect of trabeculectomy on intraocular pressure of the untreated fellow eye in the collaborative initial glaucoma treatment study. Ophthalmology 2010;117(11):2055‐60. - PMC - PubMed
Review Manager 2014 [Computer program]
    1. Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager 5 (RevMan 5). Version 5.3. Copenhagen: Nordic Cochrane Centre, The Cochrane Collaboration, 2014.
Sandhu 2017
    1. Sandhu A, Jayaram H, Hu K, Bunce C, Gazzard G. Ab interno supraciliary microstent surgery for open angle glaucoma. Cochrane Database of Systematic Reviews 2017, Issue 9. [DOI: 10.1002/14651858.CD012802] - DOI - PMC - PubMed
Tóth 2019
    1. Tóth M, Shah A, Hu K, Bunce C, Gazzard G. Endoscopic cyclophotocoagulation (ECP) for open angle glaucoma and primary angle closure. Cochrane Database of Systematic Reviews 2019, Issue 2. [DOI: 10.1002/14651858.CD012741.pub2] - DOI - PMC - PubMed
UKGTS 2015
    1. Garway‐Heath, Crabb DP, Bunce C, Lascaratos G, Amalfitano F, Anand N, Azuara‐Blanco A, Bourne RR, Broadway DC, Cunliffe IA, Diamond JP, Fraser SG, Ho TA, Martin KR, McNaught AI, Negi A, Patel K, Russell RA, Shah A, Spry PG, Suzuki K, White ET, Wormald RP, Xing W, Zeyen TG. Latanoprost for open‐angle glaucoma (UKGTS): a randomised, multicentre, placebo‐controlled trial.. Lancet 2015 Apr 4;385(9975):1295‐304. - PubMed

References to other published versions of this review

Otarola 2017
    1. Otarola F, Hu K, Gazzard G, Bunce C. Ab interno trabecular bypass surgery with Schlemm´s Canal Microstent (Hydrus) for open angle glaucoma. Cochrane Database of Systematic Reviews 2017, Issue 8. [DOI: 10.1002/14651858.CD012740] - DOI - PMC - PubMed

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