The registry provides real-world evidence of safety, and durable efficacy of a glaucoma surgery device.
Findings from a “real-world” study show that the multimodal minimally invasive glaucoma surgery (MIGS) device (Hydrus Microstent, Ivantis) safely and effectively treats a wide variety of glaucoma types, providing reductions in IOP and medication burden that are durable through at least three years.
Jeffrey Whitman, MD, reported the findings as the ASCRS-ASOA annual meeting, held May 3-7 at the Convention Center in San Diego, CA.
Dr. Whitman presented data from the SPECTRUM registry that was developed to collect outcomes data for patients treated with the MIGS device either in combination with cataract surgery or as a standalone procedure.
“It is important to state what is meant by ‘real-world’. The SPECTRUM registry includes all-comers,” said Dr. Whitman, president and chief surgeon, Key-Whitman Eye Center, Dallas, TX.
“It is a global, multicenter registry including data from 51 centers in 17 countries, all outside of the United States.”
Dr. Whitman noted that about 2,500 eyes were enrolled through 2018, and they were implanted with the MIGS device either in a combination procedure with phacoemulsification and IOL implantation or they were phakic or pseudophakic and had standalone glaucoma surgery.
“The large population of enrolled eyes also represents the full spectrum of glaucoma severity, from mild through advanced, including eyes with glaucoma refractory to prior incisional/filtration surgery,” he added.
Centers contributing to the SPECTRUM registry are located in Europe, North America, South America, the Middle East, and Asia. Almost three-fourths of the nearly 2,500 treated eyes had primary open angle glaucoma. Other glaucoma types included primary angle closure glaucoma (9%), pseudoexfoliation glaucoma (7%), and pigmentary dispersion glaucoma (3%).
The patients had a mean age of 71.5 years, 53% were female, and mean baseline mean deviation was -7.2 dB. In addition to medications, prior glaucoma treatments included filtration surgery in almost 10% of eyes, trabeculoplasty in 20% and iridotomy in almost 8%.
Outcomes in combination surgery cohort
Dr. Whitman presented outcomes for patients who had combined cataract and microstent surgery, which represented 74% of the eyes enrolled in the SPECTRUM registry. Data were analyzed from 1119 eyes seen at 12 months, 562 eyes followed to 24 months, and 207 eyes that completed a 36-month visit. Mean baseline IOP for the three cohorts ranged from 18.6 to 19.8 mmHg and mean number of hypotensive medications being used at baseline was 2.2 or 2.3.
Analyses of change from baseline IOP showed statistically significant reductions at 12 months (-3.6 mmHg), 24 months (-3.9 mmHg), and 36 months (-4.2 mmHg). Similarly, there was a statistically significant and consistent reduction in medication at all follow-up intervals showing that patients on average eliminated use of 1 medication.
“At all follow-up intervals, approximately three-fourths of eyes reduced medication burden by one or more medications. At 12 months, 58% of eyes were medication free, and even at 3 years, more than 42% of eyes were using no ocular hypotensive medications,” Dr. Whitman said.
At 12 and 24 months, IOP was ≤21 mmHg in 95% and 96% of eyes, respectively, and ≤18 mmHg in 87% and 86% of eyes, respectively. At 3 years, 92% of eyes had an IOP ≤21 mmHg and IOP was ≤18 mmHg in 79% of eyes.
The safety analysis included data from the full cohort of eyes enrolled in SPECTRUM through 2018, and it showed that rates of intraoperative and postoperative adverse events were very low.
“Rates of device malposition, hyphema >2 mm, postoperative IOP spikes, and postoperative peripheral anterior synechiae were all less than 1%,” reported Dr. Whitman.
Intraoperatively, there were 46 other adverse events (2%), which included IOP spikes, damage to the iris, and cyclodialysis among others. Postoperatively, there were a total of 20 other adverse events, including cases of visual loss, maculopathy, corneal edema/abrasion, and vitreous in the anterior chamber.
Mechanism of action
The microstent acts to optimize aqueous outflow by bypassing the trabecular meshwork. It provides precise dilation and scaffolding of Schlemm’s canal over a 90º span that enables consistent aqueous access to multiple collector channels over time.
Dr. Whitman has no relevant financial interests to disclose.