Risks Identified for Flat Anterior Chamber After BGI

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A postoperative flat anterior chamber following Baerveldt Glaucoma Implant (BGI) surgery can result in se­rious complications, with the potential to permanently damage ocular struc­tures.

“Understanding the risk factors associated with the development of complications will help glaucoma surgeons in selecting the best surgical intervention for their patients,” said Huda Sheheitli, MD, at the University of Minnesota, Minneapolis, and lead author of a study that identified three key risk factors for flat anterior cham­ber after BGI surgery.¹

Methodology. Dr. Sheheitli and col­leagues reviewed data on 42 eyes that underwent BGI surgery and went on to develop flat anterior chamber requiring surgical intervention within a 90-day period after the procedure. Cases were treated at Anne Bates Leach Eye Hospital in Miami between 2011 and 2019. For their study, the researchers matched each case with two controls. The variables assessed in the study included the individual’s sex, diagnosis, the presence of diabetes and hyperten­sion, the administration of pre- and postoperative glaucoma medications, other ocular conditions, and IOP.

Results. Patients who developed a flat anterior chamber were more likely to be female (69.1% versus 41.7% con­trols), to have a history of taking oral carbonic anhydrase inhibitors (CAIs) at tube opening (21.4% versus 7.1%), and to have pseudoexfoliation syndrome (23.8% versus 6.0%). Patients partici­pating in the study were less likely to be using cholinergic agonists (0.0% versus 11.9%) at baseline and were less likely to have primary open-angle glaucoma (42.9% versus 64.3%). They were also older (mean age 75.9 versus 64.9 years) and had an earlier tube opening time (5.6 versus 6.2 weeks) and lower IOP after tube opening (7.2 mm Hg versus 14.4 mm Hg). However, their IOP before opening was higher (24.7 versus 19.5 mm Hg), the authors reported.

Takeaways. The researchers reported that those patients most likely to require additional intervention in the 90-day period after BGI surgery were older, prescribed CAIs at tube opening, and more likely to have higher IOP prior to tube opening.

Dr. Sheheitli said the findings paint a more complete picture of the risks for flat anterior chamber after BGI surgery. “Our study highlights the risk factors that could contribute to the develop­ment of this complication,” she said.

She recommended that surgeons consider alternatives to BGI “in patients with significantly elevated preoperative IOP requiring the use of oral CAI.” She also said the findings lead to the rec­ommendation that surgeons consider the use of flow-restricting glaucoma implants in older patients. She also suggested glaucoma specialists consid­er holding off on the use of oral CAI medications one to two weeks before opening the tube (the tube is typically tied off at the time of surgery and then opened up six weeks after surgery).

The study can be a guidepost for col­leagues, said Dr. Sheheitli, stressing that trabulectomy and glaucoma drainage implants are among the most commonly performed surgical procedures world­wide for glaucoma and “remain the standard of care for glaucomatous neu­ropathy resistant to medical therapy.”

That said, while these procedures lower IOP, all surgical options should be weighed for patients with risk factors for complications.

—Brian Mastroianni

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1 Sheheitli H et al. Am J Ophthalmol. 2023;256:39-45.

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Relevant financial disclosures: Dr. Sheheitli—None.

For full disclosures and the disclosure key, see below.

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