Micro-stent may be stand-alone option when topical glaucoma therapy fails

Take-Home

Supraciliary micro-stent implantation can serve as a safe and effective stand-alone treatment in patients refractory to topical glaucoma therapy.

Dr. Nguyen

By Lynda Charters; Reviewed by Quang H. Nguyen, MD

La Jolla, CA-Patients with open-angle glaucoma (OAG) whose medical therapy has failed, and who are under consideration for trabeculectomy, may find an alternative treatment in a supraciliary micro-stent (CyPass Micro-Stent, Transcend Medical) that lowers and maintains IOP over the long term.

Implantation of the device also lowers the medication treatment burden and may preclude the need for a more invasive surgery, such as trabeculectomy or a glaucoma drainage device, said Quang H. Nguyen, MD, director of the glaucoma service, Scripps Clinic, La Jolla, CA.

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To date, a number of studies of the efficacy and safety of the micro-stent have been conducted in more than 1,000 subjects worldwide. Three studies are ongoing: the DUETTE and CYCLE European studies of 65 and 500 patients, respectively, and the U.S. IDE COMPASS study of 505 patients. The 2-year follow-up data from the COMPASS study are expected in 2015.

NEXT: The Duette Study

The Duette Study

The DUETTE Study is a prospective eight-site European trial that evaluated the micro-stent implantation as a stand-alone procedure for treating OAG in 65 patients refractory to topical medications, according to Dr. Nguyen, an investigator in the U.S.-based COMPASS randomized, controlled trial.

Study outcomes were intra- and postoperative safety, as well as efficacy measured by IOP lowering, through 12 months. Patients had grades III/IV OAG and treated IOP between 21 and 35 mm Hg with between 1 to 4 medications. Patients were being considered for trabeculectomy at the time of enrollment.

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The average patient age was 68.3 ± 10.5 years; 69% were women. The mean baseline IOP was 24.5 ± 2.8 mm Hg. Patients took a mean of 2.2 ± 1.1 medications (36.9% took 3 or more medications; 30.8% 2 or more medications; 26.2% 1 medication; and for 3.1% the number of medications was unknown). Most patients (63.1%) were phakic. All patients were followed for 12 months.

The mean IOP decreased from the baseline of 24.5 to 16.7 mm Hg at 12 months, Dr. Nguyen noted. The mean percent change in IOP at 6 months postoperatively was –30% and at 12 months –32%.

No serious major adverse events occurred. The most frequent adverse event was a transient increase in IOP over 30 mm Hg for more than 1 month postoperatively (n = 7 eyes). Transient hyphema developed in 4 eyes for less than 1 month postoperatively, cataracts progressed in 5 eyes with pre-existing cataracts, and 2 eyes each had a loss of best-corrected visual acuity of two lines or more and peripheral anterior synechiae. Eleven patients required secondary glaucoma surgery.

NEXT: Material, design 

Medication use also decreased from a mean of 2.2 medications preoperatively to 1.3 and 1.5 medications at 6 and 12 months postoperatively. Need for trabeculectomy was avoided in 85% of cases, as adequate control was achieved with the micro-stent.

“The 12-month DUETTE results showed improved IOP control and a lower medication burden after implantation of the [device],” he said.

The safety profile reflected a microinvasive procedure. No sight-threatening complications developed. In all cases of cataract progression, investigators noted that patients already had pre-existing cataract preoperatively. All cases of hyphema resolved within 1 month.

Material, design

The micro-stent-made of a biocompatible, non-degradable, polyimide material-is implanted using a clear corneal, 1.5-mm incision with an ab interno approach.

The conjunctiva, sclera, and trabecular meshwork remain intact. The device is designed to use the same outflow pathway as prostaglandin analogues, he noted. 

Quang H. Nguyen, MD

E: nguyen.quang@scrippshealth.org

Dr. Nguyen is an investigator for Transcend Medical. The CyPass Micro-Stent is an investigational device in the United States.