February 2019

COVER FEATURE

Facing complicated glaucoma cases
Balancing risks and benefits


by Vanessa Caceres EyeWorld Contributing Writer


Heme after Kahook Dual Blade procedure

Heme viewed though gonioscopy after MIGS procedure

Heme after OMNI Glaucoma Treatment System procedure

Diffuse heme after OMNI Glaucoma Treatment System procedure
Source (all): Steven Vold, MD

Managing anticoagulation therapy in glaucoma patients requires careful review of medications, techniques

With a sizable number of older patients on anticoagulation therapy, glaucoma specialists must constantly decide what surgical modifications are needed to prevent complications in this patient subgroup—particularly if the patients are unable to stop chronic anticoagulation therapy.

Managing medications

Generally speaking, Douglas Rhee, MD, University Hospital Eye Institute, 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 internists and cardiologists are more than happy to assist with a heparin bridge or adjusting warfarin in preparation for intraocular surgery,” said Brian Song, MD, Kaiser Permanente–Southern California Permanente Medical Group, Fontana, California.
Richard Lewis, MD, Sacramento, California, also will not stop anticoagulants before surgery.
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 medicolegal 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-inflammatory 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. Specifically, he would like to know how their discontinuation or reversal affect the risk of hemorrhagic complications associated with glaucoma surgery.
Glaucoma surgeons should do their best to keep up with the constantly 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 microinvasive 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 trabecular 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 the IOP decrease with a given MIGS procedure is modest, he added.
That said, Dr. Song sometimes will offer MIGS to a patient using only antiplatelet therapy, such as aspirin. “In our own study of hemorrhagic complications from glaucoma surgery, continuation of anticoagulation therapy was associated with a higher rate of hemorrhagic complications than antiplatelet therapy. While our study did not include MIGS procedures, I do think this finding is applicable in other clinical scenarios as well,” Dr. Song said.
In Dr. Vold’s experience, it’s better to avoid trabecular bypass cutting procedures such as a goniotomy or the Kahook Dual Blade (New World Medical, Rancho Cucamonga, California) in anticoagulant therapy patients. However, he sees fewer issues with most other MIGS approaches. “The key thing is you don’t want to open a blood vessel,” he said. Stay aware of potential long-term risks; after a Trabectome (NeoMedix, Tustin, California), a patient could cough years later and have a small hyphema in the anterior chamber, Dr. Vold cautioned.

Other surgical approaches and pearls

Proper surgical technique in patients on chronic anticoagulation therapy can help lead to a flat anterior chamber and reduce the risk for bleeding. A few pearls shared with EyeWorld by glaucoma specialists include the following:
• Consider transscleral laser, such as micropulse cyclophotocoagulation. “Though I routinely perform a retrobulbar block prior to transscleral diode laser, I find that some patients are able to tolerate micropulse cyclophotocoagulation with heavy intravenous sedation in the absence of a block,” Dr. Song said. “I like this option for anticoagulated patients since it is noninvasive and also avoids the risk of a retrobulbar hemorrhage by forgoing the block.”
• Pre-place scleral flap sutures when performing a trabeculectomy, Dr. Song advised. However, consider using a non-valved glaucoma drainage device such as a Baerveldt 250 (Johnson & Johnson Vision, Santa Ana, California) or Molteno3 (Molteno, Dunedin, New Zealand) if the patient does not require an immediate IOP reduction. “These devices potentially allow for more controlled pressure reduction via laser suture lysis of the ligature suture during the postop period,” he explained.
• Tie the sutures a little more tightly during trabeculectomy, Dr. Vold recommended. Wait a couple of weeks to cut the stitches.
• Make a paracentesis at the 6 o’clock position in case of a postop hyphema. “The inferior paracentesis can be used to drain a hyphema at the slit lamp and avoid returning to the OR for an anterior chamber washout in some cases,” Dr. Song said.
• Don’t overlook anesthesia, said Dr. Song, who usually will give a sub-Tenon’s block instead of a peribulbar or retrobulbar block.
• If a patient is able to stop anticoagulant therapy, make sure it is out of his/her system before proceeding with surgery. For instance, Dr. Vold generally waits 3 days after warafin is stopped. Otherwise, you still could experience negative after effects.
• Consider using a drainage device such as the Ahmed valve (New World Medical) instead of a trabeculectomy, and use a sutured tube to avoid postop hypotony, Dr. Lewis recommended.
• Use an ophthalmic viscosurgical device more copiously intraoperatively to help limit bleeding, Dr. Lewis advised.

Editors’ note: Dr. Lewis has financial interests with Aerie Pharmaceuticals (Irvine, California), Allergan (Dublin, Ireland), Alcon (Fort Worth, Texas), and other ophthalmic companies. Dr. Vold has financial interests with Aerie Pharmaceuticals, Alcon, Glaukos (San Clemente, California), and other ophthalmic companies. The other physicians have no financial interests related to their comments.

Contact information

Lewis: rlewiseyemd@yahoo.com
Rhee: dougrhee@aol.com
Song: brian.j.song@kp.org
Vold: svold24@gmail.com

Balancing risks and benefits Balancing risks and benefits
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