SPS-310 Minimally Invasive Glaucoma Surgery: Micro-Bypass Stents, Microstents | ASCRS
2020 ASCRS Virtual Annual Meeting

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Papers in this Session
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Real-World US Experience with 2nd Generation Trabecular Micro-Bypass Stents (iStent inject®) Implanted in Conjunction with Cataract Surgery
Author
Steven R. Sarkisian Jr., MD

Methods
This retrospective, consecutive case series from a single glaucoma surgeon includes 31 eyes with open-angle glaucoma (OAG) that underwent iStent inject implantation combined with cataract surgery. Assessments include intraocular pressure (IOP), medication use, and standard safety evaluations. Last follow-up takes into consideration all available data at different follow-up timepoints, including a subset reaching 12 months postoperative. Continued patient monitoring and data collection are ongoing with the intent of reporting a larger sample size with longer-term outcomes by the time of the presentation.

Results
In the current cohort, 31 patients with mild to moderate OAG and mean age of 67.9 years were successfully implanted with iStent inject stents in conjunction with cataract surgery. Mean preoperative IOP was 17.3 ± 5.1 mmHg on 1.2 ± 1.2 medications. Mean IOP at the last follow-up visit was 14.2 ± 3.7 mmHg on 0.4 ± 0.9 medications (average follow-up time is ~5 months). This represents a 18% IOP reduction (3.1 mmHg reduction) and a 67% medication reduction (p<0.05 for both IOP and medications). 74% of eyes were med-free at the last follow-up visit compared to 42% prior to surgery. Favorable safety was observed with no significant intraoperative or postoperative complications.

Conclusion
iStent inject adds to existing treatment options for glaucoma. Early outcomes from this study show promising IOP and medication reductions in mild-moderate OAG, with favorable safety; longer-term data will be useful as US surgeons are introduced to the device. The combination of safety and effectiveness are consistent with published literature.
Long-Term Safety and Patient Reported Outcomes on 2nd Generation Trabecular Micro-Bypass Stent System
Author
Thomas W. Samuelson, MD

Methods
Endothelial cell density (ECD) and endothelial cell loss (ECL) >30% from baseline were assessed in 2 study groups (iStent inject + phaco (INJ; n=135); phaco alone (CS; n=40)) over 3 years. PRO were collected using Visual Function Questionnaire (VFQ-25) and Ocular Surface Disease Index (OSDI) over 2 years. A post-hoc exploratory analysis was conducted. PRO responders were compared using logistic repeated measures mixed model and stratified by (1) baseline IOP (<25 mmHg and ≥25 mmHg) and (2) prostaglandin use at screening (yes/no). Minimal important difference (MID) was calculated for composite scores using a distributional approach whereby MID was defined as half the SD of baseline scores.

Results
At 3-years follow-up, mean central ECD % change from Screening was similar between INJ and CS (-12% vs -14%, respectively). ECL >30% was also similar (6.7% in INJ eyes vs 10.0% CS eyes). For PROs, a greater percentage of responders was observed at all follow-up visits over 2 years in the INJ group compared with the CS group for the ≥25 mmHg IOP and for no prostaglandin use strata, with treatment differences in composite score responder rates ranging from 10.8% to 21.7% and 13.7% to 28.8%, respectively. A 10% difference in the percentage of PRO responders between study groups, rather than statistical significance, was considered to be clinically meaningful.

Conclusion
The 3-year data demonstrates similar long-term corneal endothelial safety in INJ and CS eyes. Results of a post-hoc exploratory analysis of the VFQ-25 and OSDI suggest cataract surgery plus iStent inject may improve overall ocular symptoms and visual functioning compared with cataract surgery alone.
One Years Results after the Implantation of the Trabecular Micro-Bypass
Author
Magda B. Rau, MD

Purpose
To evaluate the safety and clinical outcomes of an ab interno Trabecular Micro Bypass iStent inject (Glaucos) In patients with open-angle (OAG) and pseudo exfoliation glaucoma undergoing combined procedure with cataract surgery or as a standalone procedure.

Methods
Trabecular Micro-Bypass System consists of two small titanium stents that are pre-loaded into a stent delivery injector 20 Eyes were enrolled in the study. 12 psedophacic eyes with primary open-angle glaucoma, 8 eyes with cataract and pseudo-exfoliative glaucoma.In 12 eyes iStent inject was implanted as stand alone procedure in the 8 eyes with cataract as combined procedure ,through the same corneal incision using an ab inferno approach in the eyes with pseudo exfoliation glaucoma. After tree months the position of the iStent inject in iridocorneal angle was observed. The effect was examined in assessment of the number of IOL reduction and number of the IOP-lowering medications.

Results
All implants were placed successfully without threatening adverse events. The position of the iStent in angle one year was stable, in one eye we observed slight fibrotisation, which could be solved with Yag Laser treatment. There was no migration, no obstruction of iStent inject The baseline for the pseudophacic patients with OAG was 26mm Hg after 12 months 18,6, the number medications 3,2after 1 year 1,8, the baseline of pseudo-exfoliative glaucoma eyes with combined procedure was 28 mm Hg after 1 year 16,6 the number of medication 1,8 after 1 year 0,7 .The mean IOP after one year was 17,6, the number or medications 1,7.

Conclusion
As a micro invasive procedure for OAG Trabecular Micro-Bypass implantation combined with cataract surgery or as stand alone procedure was associated with stable position in iridocorneal angle and effective at lowering IOP and IOP-lowering medication use at three years.
Second-Generation Trabecular Micro-Bypass Stents (iStent inject®) with Cataract Surgery in Open-Angle Glaucoma: Single-Surgeon Outcomes
Author
Mark J. Gallardo, MD

Methods
Retrospective case series of iStent inject implantation with phacoemulsification cataract surgery at a private ophthalmology center in El Paso, Texas. Efficacy measures consisted of mean intraocular pressure (IOP), mean number of medications (meds), and proportional analyses of IOP and med burden. Safety outcomes included visual acuity, visual fields, retinal nerve fiber layer thickness, and adverse events and complications. A larger cohort with longer-term outcomes will be available by the time of the conference, as follow-up is ongoing.

Results
This series included 56 eyes with predominantly primary open-angle glaucoma (POAG, 98%) and Hispanic ethnicity (66%); 39 eyes had 3- and 6-month data. Preoperatively, mean IOP was 16.8 mmHg on 1.71 mean meds (range 0-4 meds). Postoperatively, mean IOP reduced to 13.3 mmHg at 3 months (20.8% reduction; p=0.0004) and 12.7 mmHg at 6 months (24.4% reduction; p<0.0001); mean med burden reduced to 0.26 meds at 3 months (84.8% reduction; p<0.0001) and 0.18 meds at 6 months (89.5% reduction; p<0.0001). At 6 months postoperatively, 89.7% of eyes were med-free (vs 17.9% preoperatively), and 87.2% of eyes had IOP ≤ 15 mmHg (vs 35.7% preoperatively). Safety was favorable throughout.

Conclusion
This real-world iStent inject dataset showed substantial IOP and med reductions through 6 months postoperatively in a predominantly Hispanic patient population with POAG. This efficacy was accompanied by favorable safety, reinforcing current literature on the durable and safe performance of iStent inject in glaucoma.
2 Year Outcomes of 2ndgeneration Trabecular Micro-Bypass Stents (iStent inject) Combined with Cataract Surgeryda
Authors
David K. Manning, MD
Alexandros Ioannidis, MD
Michael Shiu, FRANZCO
Frank W. Howes, MD
Simon E Skalicky, FRANZCO
Todd W Goodwin, MBBS
Colin I. Clement, MD

Methods
Multi-surgeon, multi-center retrospective case series of iStent inject implantation with cataract surgery in eyes with various types of glaucoma or ocular hypertension. Efficacy was assessed by mean intraocular pressure (IOP) and medications (meds), and proportional analyses of IOP and medication burden. Safety measures included visual acuity, cup-to-disc ratio, visual fields, and adverse events and complications.

Results
309 eyes underwent iStent inject implantation with cataract surgery and completed 2 years of follow-up. Diagnoses included: primary open-angle glaucoma (71%), ocular hypertension/glaucoma suspect (9%), appositional angle-closure glaucoma (8%), and normal-tension glaucoma (6%). Preoperatively, mean IOP was 16.4 ± 4.9 mmHg on 1.47 ± 1.21 mean meds, and 42% of eyes had prior glaucoma procedures. Two years after surgery, mean IOP was 13.7 mmHg (16% reduction; p<0.0001), and 77% of eyes had IOP ≤ 15 mmHg (vs. 51% preop). Mean number of meds reduced by 66% to 0.50 meds (p<0.0001), and 74% of eyes were med-free (vs. 26% preop). Safety was favorable, similar to cataract surgery.

Conclusion
This 2-year multi-center study showed sustained and significant IOP and med reductions after iStent inject implantation with cataract surgery. Three-quarter of eyes were med-free at 2 years. This comprises one of the largest real-world cohorts to-date on iStent inject, and confirms existing evidence of the efficacy and safety of the stents.
Trabecular Microbypass Stent Implantation with Cataract Extraction in Pseudoexfoliative Glaucoma: 6 Year Results
Authors
Tanner J. Ferguson, MD
Zachary C. Dockter
Justin A. Schweitzer, OD
Mitch J. Ibach, OD
Kayla L. Karpuk, OD
Russell Swan, MD
John P. Berdahl, MD

Purpose
To evaluate the long-term safety and efficacy of a trabecular microbypass stent (iStent) combined with cataract surgery in patients with pseudoexfoliative glaucoma (PXG)

Methods
Retrospective, consecutive case series from September 2012 to December 2015. Series included 117 eyes implanted with a trabecular microbypass stent with concomitant phacoemulsification. Data was collected pre-operatively, and post-operatively at 1 day, 1 week, months 1, 3, 6 out to 6 years. Data included intraocular pressure (IOP) and number of glaucoma medications. Safety profile was established by noting the incidence of post-operative IOP pressure spikes and need for additional surgery.

Results
Mean IOP was reduced to 14.9 ± 4.7 mmHg (p<0.01) at 6 years postoperative from 20.5 ± 4.5 mm Hg at baseline. The mean number of glaucoma medications was 1.4 ± 1.0 pre-operatively and 1.0 ± 1.0 6 years after surgery. In eyes with baseline IOP ≥18 mmHg, mean IOP was reduced from 23.4 ± 6.0 at baseline to 16.3 ± 4.5. Postoperatively, 5% of eyes had IOP increases ≥15 mmHg above their baseline IOP and 5 eyes underwent additional surgery.

Conclusion
The insertion of 1 I trabecular micro-bypass stent with cataract extraction provides sustained IOP (>5 mmHg) reduction out to 6 years after surgery in eyes with PXG. Eyes with a higher baseline IOP achieved a more robust reduction in pressure.
Reduction in Incisional Glaucoma Surgery 4-Years after a Schlemm’s Canal Microstent and Cataract Surgery in Primary Open Angle Glaucoma
Author
Nathan M. Radcliffe, MD, ABO

Purpose
The purpose of this study was to assess 4-year outcomes in patients who underwent cataract surgery alone compared to those who underwent cataract surgery combined with a Hydrus® Microstent.

Methods
Subjects with primary open angle glaucoma (POAG) and visually significant cataract with washed-out diurnal IOP 22 - 34 mmHg were randomized 2:1 to undergo cataract surgery with or without a Hydrus Microstent in the HORIZON study. Scheduled study visits were conducted through 48 months postoperative. 556 eyes were randomized after cataract surgery to Hydrus (HS, N=369) or no further treatement (CS, N=187). The HS and CS groups did not differ with respect to baseline demographics or ocular characteristics. Pre-surgery washout diurnal IOP was 25.5 ± 3.0 vs 25.4 ± 2.9 mmHg (p=0.9) and visual field mean deviation was -3.61 ± 2.49 dB vs -3.61 ± 2.60 dB (p=1.0).

Results
At 4 years, the proportion of eyes requiring medications was significantly lower in the HS group (31% vs. 59%, p<0.001). Among eyes that were medication free, the mean unmedicated IOP was unchanged vs 2 years (16.6 vs. 16.7 HS group and 17.4 vs. 17.3 CS group). There was a significant reduction in the cumulative risk of incisional glaucoma surgery at 4 years in the HS group (1.9% vs. 6.9%, Hazard Ratio = 0.25, p=0.013, logrank p=0.007). From 2 to 4 years, mean central endothelial cell count fell by 3% in the HS group (2060±480 vs. 2014± 502, p=0.9) and 2% in the CS group (2183±425 vs. 2144±420, p=0.9). There were no significant differences in other adverse events at 4 years vs 2 years.

Conclusion
Hydrus microstent when combined with phacoemulsification results in sustained IOP and medication reduction for up to 4 years postoperative. The treatment arm showed a significant reduction in secondary incisional glaucoma surgery (trabeculectomy or tube shunt) despite similar IOP, possibly related to sustained 4 year reduction in medication use.

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