Filtration device lowers IOP in patients with PEG and POAG

Take-home message: A glaucoma filtration device was equally effective in reducing IOP in pseudoexfoliative glaucoma and primary open-angle glaucoma patients, in a recent small study.

By Nancy Groves, Reviewed by Dr Shimon Rumelt

Outcomes of implantation for a glaucoma filtration device (ExPress, Alcon Laboratories, Fort Worth, Texas, USA) in pseudoexfoliative glaucoma (PEG) and primary-open angle glaucoma (POAG) demonstrated significant decreases in IOP and anti-glaucoma medication use in both groups in a recent comparison study.

“Despite the more aggressive course of secondary glaucoma of the pseudoexfoliative type, the device works similarly in both groups and outcomes were effective and similar,” said Dr Shimon Rumelt, Western Galilee Nahariya Medical Center, Nahariya, Israel. “That means that the use of the device (the ExPress model D50) is as effective in PEG as it is in POAG.”

The authors had experienced different outcomes with standard trabeculectomy and wanted to analyse data on the device, not only as an alternative surgical technique, but also to evaluate its efficacy in PEG compared with the more often-studied outcomes of shunt implantation in POAG.

The device’s long-term performance was also of interest, given that IOP reductions achieved with trabeculectomy may diminish over time. The shunt’s main purpose is to preserve an open sclerostomy.

Dr Rumelt added that performing surgery with the shunt is more expensive than a standard trabeculectomy, so its efficacy must be demonstrated to justify this option.

Study outcomes

The study included 35 eyes (n = 29) with PEG and 20 eyes (n = 16) with POAG. Patients had uncontrolled glaucoma and had not had a prior trabeculectomy, although many patients had undergone other forms of ocular surgery. The physicians reviewed the charts of patients who had undergone shunt implantation from 2006 to 2013; the average follow-up was 12.5 months.

Patient demographics in both groups were similar. However, mitomycin-C use during surgery was higher in the PEG group (60% versus 25%, P = 0.012) due to a higher rate of previous ocular surgeries in the PEG cohort.

“In both groups, the postoperative IOP decreased profoundly and anti-glaucoma medication was also comparable, although they are different types of glaucoma with different progression and different prognosis,” Dr Rumelt explained.

The preoperative IOP was 17 to 40 mmHg in the eyes with PEG and 21 to 45 mmHg in the eyes with POAG. Postoperatively, the respective ranges were 2 to 23 mmHg and 2 to 15 mmHg. The average decrease in IOP was 20.6 ± 7.5 mmHg in the PEG group and 19.1±6.7 mmHg in the POAG group (P = 0.725).

Before implantation of the shunt, patients in the PEG group were taking a total of 2–5 medications, and those with POAG were taking 3–5. The numbers declined after surgery to 0–2 medications in the PEG group and 0–4 in the POAG group. The number of eyes with complications was 11 (31%) in the PEG group and 4 (20%) in the POAG group.

Secondary glaucoma

Dr Rumelt and Dr Bersudsky also displayed a second poster at the Academy meeting comparing the outcomes of surgery with the Ex-Press shunt in different types of secondary glaucoma. The analysis of 43 eyes demonstrated that the device was effective in all types of secondary glaucoma except neovascular glaucoma (2 patients) and iridocorneal endothelial syndrome (1 patient).

“We do not recommend using the device in these two types of glaucoma,” Dr Rumelt said.

In the failed procedures, the shunt eventually filled with fibrovascular growth or abnormal endothelium. Dr Rumelt also added that despite the use of laser treatment and surgical revision, the failure could not be reversed.

However, Dr Rumelt reported that he is aware of two unpublished cases in which iridocorneal endothelial syndrome was successfully treated with the shunt. The aggressiveness of the disease may be an important factor in the success of the procedure.

“Despite good results in both studies, it is important to study the long-term outcomes of shunt implantation and to obtain data from 10 or more years of follow-up to justify the use of the implant,” Dr Rumelt concluded.

Dr Shimon Rumelt

E: shimon.rumelt@naharia.health.gov.il

This article was adapted from a poster presentation by Dr Shimon Rumelt and co-author Dr Valery Bersudsky at the 2014 meeting of the American Academy of Ophthalmology.

Neither author indicated any proprietary interest in the subject matter.