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EW FEATURE 44 Facing complicated glaucoma cases • February 2019 AT A GLANCE • Many glaucoma surgeons want patients on chronic anticoagulation therapy to continue medications before and during surgery. • However, surgical choice and technique often are altered due to use of anticoagulant therapy. • MIGS should be done with caution in this patient population. • Studies that demonstrate the effects of newer direct-acting anticoagulants on hemorrhaging would be useful for glaucoma surgeons. by Vanessa Caceres EyeWorld Contributing Writer ically, he would like to know how their discontinuation or reversal affect the risk of hemorrhagic com- plications associated with glaucoma surgery. Glaucoma surgeons should do their best to keep up with the con- stantly expanding anticoagulation options, Dr. Vold advised. When in doubt, discuss individual patient risks with the patient's primary care doctor. Proceeding with MIGS The decision to perform microinva- sive glaucoma surgery (MIGS) in a patient on chronic anticoagulation therapy can be a challenging one. For his part, Dr. Song prefers to avoid MIGS with this subgroup. "I think the most attractive feature of MIGS is predicated on the increased safety profile of these procedures when compared to traditional transscleral glaucoma surgery," Dr. Song said. "However, hyphemas are a known complication of trabec- ular bypass procedures and tend to be more common in patients on anticoagulation therapy." The potential benefits of MIGS could be compromised if there is blood in the anterior chamber, especially when A conversation with these patients about surgical risks and medication use also is important, said Steven Vold, MD, Vold Vision, Fayetteville, Arkansas. A detailed talk about risks and benefits both informs patients and addresses med- icolegal concerns, he said. "In these patients, I will have a detailed discussion about the increased risks associated with glaucoma surgery, particularly vision loss from a suprachoroidal hemorrhage, so that the patient is able to make the most informed decision possible," Dr. Song said. He also considers other factors such as patient age, glaucoma severity, rate of glaucoma progression, and other comorbidities when deciding if and how to proceed with surgery. Dr. Song will advise patients to avoid oral nonsteroidal anti-inflam- matory drugs for postop pain, and if anticoagulation therapy is stopped, he will have them restart therapy right after surgery. Something that will be helpful for glaucoma surgeons to know going forward is the effect of newer direct-acting oral anticoagulation agents such as dabigatran (Pradaxa, Boehringer Ingelheim, Ingelheim, Germany) and rivaroxaban (Xarelto, Janssen Pharmaceuticals, Raritan, New Jersey), Dr. Song said. Specif- ly if the patients are unable to stop chronic anticoagulation therapy. Managing medications Generally speaking, Douglas Rhee, MD, University Hospital Eye In- stitute, Cleveland, prefers to have patients on chronic anticoagulation therapy continue their medication, unless they are using it only for general health or as preventative medicine. If they are using it for prior deep vein thrombosis, prior pulmonary embolism, cardiac stents or other vascular stents, or a history of atrial fibrillation, Dr. Rhee does not request that patients stop using the medications. "I may be a little more conservative, but my rationale is in the worst-case scenario, I'd opt to have a risk of complications from glaucoma surgery rather than risk a stroke, heart attack, or death," he said. "I have found that most in- ternists and cardiologists are more than happy to assist with a hepa- rin bridge or adjusting warfarin in preparation for intraocular surgery," said Brian Song, MD, Kaiser Perma- nente–Southern California Perma- nente Medical Group, Fontana, California. Richard Lewis, MD, Sacramen- to, California, also will not stop anticoagulants before surgery. Managing anticoagulation therapy in glaucoma patients requires careful review of medications, techniques W ith a sizable number of older patients on anticoagulation thera- py, glaucoma special- ists must constantly decide what surgical modifications are needed to prevent complications in this patient subgroup—particular- Balancing risks and benefits continued on page 46 open angle glaucoma, and visual- ly significant cataract. His results showed a visual improvement to 20/40 and by at least two lines in 13 of the study patients, a decrease in medications from 0.9 to 0.7 (p=.8), and an average IOP decrease of 1.7 mm Hg. Only one eye required a graft exchange and another required a glaucoma valve to better control IOP. 6 Each surgeon will have an indi- vidual approach to highly compli- cated surgical scenarios. Dr. Ayyala does not advise combining DSEK and glaucoma surgery due to the dif- ficulties in maintaining the air bub- ble in the anterior chamber needed to float the graft, particularly when the glaucoma surgery in question is a trabeculectomy or GDD. On the other hand, canal based procedures such as the iStent and Kahook Dual Blade (New World Medical, Rancho Cucamonga, California) may be combined with DSEK, although it is not always advisable since these procedures are associated with reflex blood into the anterior chamber, which will complicate DSEK surgery. Dr. Ayyala follows his patients via good clinical evaluation, and he recommends serial endothelial cell counts. How to monitor "We monitor surgical glaucoma patients clinically and visually and on their regular glaucoma follow-up visits," Dr. Berdahl said. "We will do an occasional pachymetry and endothelial cell count if the vision is suboptimal, which can be helpful, but I don't think that there is an algorithmic approach to monitoring the corneal endothelium. The best thing to protect the corneal endo- thelium is good surgical technique, avoiding hypotony, and ensuring that any devices in the anterior chamber are far away from the cor- neal endothelium," he said. EW References 1. Janson BJ, et al. Glaucoma-associated corneal endothelial cell damage: a review. Surv Ophthalmol. 2017;63:500–506. 2. Ayyala RS. Penetrating keratoplasty and glaucoma. Surv Ophthalmol. 2000;45:91–105. 3. Williamson BK, et al. The effects of glau- coma drainage devices on oxygen tension, glycolytic metabolites, and metabolomics profile of aqueous humor in the rabbit. Transl Vis Sci Technol. 2018;7:14. 4. Ayyala RS, et al. Comparison of mitomycin C trabeculectomy, glaucoma drainage device implantation, and laser neodymium:YAG cyclophotocoagulation in the management of intractable glaucoma after penetrating kerato- plasty. Ophthalmology. 1998;105:1550–6. 5. Yelenskiy A, et al. Patient outcomes follow- ing micropulse transscleral cyclophotocoagu- lation: intermediate-term results. J Glaucoma. 2018;27:920–925. 6. Stunkel M, et al. Outcomes of partial-thick- ness corneal transplantation combined with trabecular bypass stent implantation and cataract surgery. Presented at the 2017 ASCRS•ASOA Symposium & Congress. Editors' note: Dr. Berdahl has finan- cial interests with Alcon (Fort Worth, Texas), Glaukos, New World Medical, and CorneaGen (Seattle). Dr. Ayyala has no financial interests related to his comments. Contact information Ayyala: rayyala@health.usf.edu Berdahl: johnberdahl@gmail.com Glaucoma continued from page 43

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