Sturdier shunt lowers intraocular pressure in glaucoma

May 1, 2010

The generation I Gold Micro Shunt Plus has been around for several years now and has proven to be an effective tool in reducing IOP to clinically beneficial levels in primary open-angle glaucoma.

Montreal-The generation I Gold Micro Shunt Plus (GMS+) (SOLX) has been around for several years now and has proven to be an effective tool in reducing IOP to clinically beneficial levels in primary open-angle glaucoma (POAG).

A newer, sturdier version of the device, generation II GMS+ (SOLX), has been shown to achieve a significantly greater reduction in IOP in patients with glaucoma, making this novel shunt a leading player in IOP-lowering devices, according to Paul J. Harasymowycz, MD.

Modifications of the generation II GMS+ device were implemented not only to reduce manufacturing process variability but also to strengthen the structural integrity of the shunt, reducing its susceptibility to mechanical damage during intraoperative surgical implantation. A delivery system also was added to allow a facilitated implantation procedure of the shunt. Internal structural changes to the generation II GMS+ include replacement of long channels with posts and shorter end-channels, which help prevent any unanticipated flow restriction due to potential mechanical compression during the placement procedure.

The generation I GMS+ device recently completed a multicenter, prospective, non-randomized clinical trial in 264 patients with uncontrolled POAG, and the generation II strengthened GMS+ currently is undergoing the same rigorous study in 41 patients with uncontrolled POAG. Participants in both trials had glaucoma with a baseline IOP of 24 mm Hg or higher that was inadequately controlled with maximally tolerated medical therapy; approximately 75% of participants had at least one prior failed laser or surgical intervention for glaucoma.

According to Dr. Harasymowycz, the 12-, 24-, and 36-month data for the generation I GMS+ device and the recently available 12-month data for the generation II strengthened GMS+ device have shown similar positive outcomes. However, the strengthened GMS+ device appears to lower IOP more effectively than its predecessor.

At 12, 24, and 36 months, the mean percent IOP reduction with the generation I GMS+ device was 36.4%, 33.7%, and 38.4%, respectively. At 12 months, IOP was lowered from a mean of 29.4 to 18.7 mm Hg, which was further reduced to 18.5 and 18 mm Hg at the 24- and 36-month follow-up, respectively, demonstrating a consistent and effective IOP-lowering trend. The mean percent reduction in medication use was 55.4% at 12 months, 54.9% at 24 months, and 48.9% at 36 months.

According to Dr. Harasymowycz, however, the superiority of the strengthened GMS+ device can be seen in its greater efficiency in IOP reduction achieved at 12 months compared with its predecessor, the generation I GMS+ device. The generation II strengthened GMS+ device could lower IOP to 15.3 mm Hg (versus 18.7 mm Hg with the generation I device) and achieve a 45.7% IOP reduction (versus 36.4%) at only 12 months out.