Caroline Helwick

November 27, 2013

NEW ORLEANS — The CyPass Micro-Stent procedure for glaucoma can be safely combined with cataract surgery, according to 2-year results from the CYCLE trial. Investigators report that the procedure provided sustained control of intraocular pressure and reduced medication use.

"This procedure is an attempt to have surgeries for glaucoma that are safer and easier for the patient," said investigator Brian Flowers, MD, from Fort Worth, Texas. "Current surgical treatments for glaucoma are associated with events such as suprachoroidal hemorrhage and bleb-related complications. Microinvasive surgical stenting of the supraciliary space may improve aqueous flow, with fewer complications," he explained here at the American Academy of Ophthalmology (AAO) 2013 Annual Meeting.

There are 2 main approaches to minimally invasive glaucoma surgery, Dr. Flowers noted. The iStent, a device approved by the US Food and Drug Administration, is put into the Schlemm's canal, whereas the CyPass is implanted in the supraciliary space, using an ab interno approach, through a clear corneal 1.5-mm incision. The latter leaves conjunctiva, sclera, and trabecular meshwork intact.

"The CyPass device is designed to enhance suprachoroidal outflow. This is the same pathway affected by prostaglandin analogs," said Dr. Flowers. "It appears that using the suprachoroidal space, you can achieve lower intraocular pressure than going through the trabecular meshwork. This is the first device to go into this location."

The study involved 136 eyes of patients with cataracts and a diagnosis of grade 3 or 4 open-angle glaucoma. Patients underwent concurrent CyPass implantation and phaco-cataract surgery, and were followed for 2 years.

The population was divided into 2 groups. Patients in cohort 1 had baseline pressure of at least 21 mm Hg, and the goals of treatment were to lower intraocular pressure and reduce the need for medication. Patients in cohort 2 had baseline pressure below 21 mm Hg, and the goals of treatment were to reduce medication use and maintain pressure control.

Both groups were treated with an average of 2 medications at baseline, but more than one third needed at least 3 agents.

"For this study, the entry criteria were fairly flexible, more like a real-world situation. Anyone who needed intraocular pressure lowering was eligible," said Dr. Flowers.

With CyPass implantation and cataract surgery combined, mean pressure was reduced by 35% in cohort 1 (P < .0001), and medication use was significantly reduced (P = .0265). In cohort 2, pressure control was sustained through 2 years and medication use was significantly reduced (P < .0001).

Table. Reduction in Intraocular Pressure and Medication Use at 2 Years

Variables Cohort 1 Cohort 2
Baseline pressure 25.5 16.4
Pressure at 2 years 15.8 16.1
Medications at baseline (n) 2.2 2.0
Medications at 2 years (n) 1.0 1.1

 

The safety profile of the procedure was very good, reported Dr. Flowers. There were no instances of hypotony, suprachoroidal hemorrhage, other retinal complications, or detachment. One device had to be explanted and 1 had to be repositioned.

One patient had inflammation beyond 1 month, 4 had an increase in intraocular pressure beyond 1 month, and 2 had transient hyphema. No cases of endophthalmitis were reported.

Asked by Medscape Medical News to comment on the study, AAO spokesperson Andrew Iwach, MD, a glaucoma specialist from San Francisco, noted that "the results draw attention to the fact that our mainstay surgical treatment, trabeculectomy and implants, is not perfect. We have to consider the data from this study to be preliminary, and we need long-term follow-up, but this report looks positive and the results are encouraging. It is an example of a trend in the surgical management of glaucoma, where we need a better way to help patients."

Dr. Flowers reports financial relationships with Alcon, Glaukos, iScience, Merck, Transcend Medicine, Ivantis, and Foresite. Dr. Iwach reports financial relationships with AcuMEMS, Alcon, Carl Zeiss Meditec, Clarity Medical Systems, IRIDEX, Ista Pharmaceuticals, Lumenis, Merck, and Pfizer.

American Academy of Ophthalmology (AAO) 2013 Annual Meeting: Abstract PO352. Presented November 19, 2013.

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