LCD L38299: Micro-Invasive Glaucoma Surgery (MIGS)

Indications of Coverage

The following are considered reasonable and necessary and covered:

• One trabecular aqueous stent device per eye which is approved for the treatment of adults with mild or moderate open-angle glaucoma (OAG) and a cataract when the individual is currently being treated with an ocular hypotensive medication and the procedure is being performed in conjunction with cataract surgery.

• One subconjunctival space stent or trabecular stent is approved for use as a standalone procedure device aqueous per eye approved for the management of refractory glaucoma, defined as prior failure of a filtering/cilioablative procedure OR uncontrolled intraocular pressure (IOP) defined as progressive damage or mean diurnal medicated IOP ≥20 mmHg on maximally tolerated medical therapy (i.e., ≥4 classes of topical IOP-lowering medications, or fewer in the case of tolerability or efficacy issues).

• Phacoemulsification/intraocular lens placement can be performed with a single MIGS procedure.

Limitations of Coverage

• Minimally invasive glaucoma surgery (MIGS) is not considered a first line treatment for mild-moderate glaucoma.

• A combination of a surgical MIGS procedure and an aqueous shunt cannot be performed at the same time of service in the same eye.

• Phacoemulsification/intraocular lens placement performed with a combination of a MIGS procedure (e.g., cataract + stent + canaloplasty or goniotomy) at the same time of service in the same eye is non-covered.

Note: A Contractor Advisory Committee Meeting on Micro-Invasive Glaucoma Surgery was held on 1/5/2023 hosted by Palmetto, CGS, NGS, Noridian, and WPS. Transcripts are available at: Jurisdiction J Part A - Multi-Jurisdictional Micro-Invasive Glaucoma Surgery Contractor Advisory Committee Meeting: January 5, 2023 (palmettogba.com) . The input from subject matter experts will be referenced throughout this policy.

Provider Qualifications

The Medicare Program Integrity Manual states services will be considered medically reasonable and necessary only if performed by appropriately trained providers. XEN45 insertion must be performed by an ophthalmologist with experience with trabeculectomy and bleb management.

Patient safety and quality of care mandate that healthcare professionals who perform minimally invasive glaucoma surgeries are appropriately trained and/or credentialed by a formal residency/fellowship program and/or are certified by either an accredited and nationally recognized organization or by a post-graduate training course accredited by an established national accrediting body or accredited professional training program whose core curriculum includes the performance and management of the procedures addressed in this policy. Credentialing or privileges are required for procedures performed in inpatient and outpatient settings. 1

Definitions

Canaloplasty- Cannulation of Schlemm’s canal with a catheter or stent with either an internal or external approach for at least three clock hours with an injection of viscoelastic while removing the stent to dilate the canal or via three or more punctures of the trabecular meshwork spanning at least three clock hours (90 degrees) to dilate Schlemm’s canal. 2

Goniotomy- Incision and/or excision with blade or surgical instrument for at least 3 clock hours of trabecular meshwork to create an opening into Schlemm's canal from the anterior chamber, via an internal approach. 3

High quality literature - Further research is very unlikely to change our confidence in the estimate of effect. 4

Maximum tolerated medical therapy- is attained as soon as the patient is successfully using the greatest number of topical glaucoma medication classes he or she can tolerate and that add additional IOP reduction. 5

Minimally Invasive glaucoma surgery (MIGS)- a group of surgical procedures that are performed using an ab interno approach and designed to reduce trauma to ocular tissues. 6

Moderate quality literature- Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. 4

Primary open-angle glaucoma (POAG) - potentially blinding condition caused by chronic, progressive optic neuropathy in adults in which there is acquired atrophy of the optic nerve with loss of retinal ganglion cells and their axons. 6

Refractory Glaucoma - When the intraocular pressure remains above target values selected to slow or halt the disease, despite the use of multiple classes of medications, or fewer medications when tolerability or effectiveness limits the use of other drug classes, or failed surgical therapy. 5

Primary open-angle glaucoma (POAG) affects approximately 53 million people in the world with a prevalence of 3% in the population aged 40-80 years. 6 POAG is a chronic, progressive optic neuropathy in adults in which there is a characteristic acquired atrophy of the optic nerve and loss of retinal ganglion cells and their axons. In the primary (conventional) outflow pathway from the eye, aqueous humor passes through the trabecular meshwork (TM), enters a space lined with endothelial cells (Schlemm’s canal), drains into collector channels, and then into the aqueous veins. Increases in resistance in the trabecular meshwork or the inner wall of the Schlemm’s canal can disrupt the balance of aqueous humor inflow and outflow, resulting in an increased intraocular pressure (IOP) and glaucoma risk. The etiology is not fully understood but there is an association with increased IOP, due to a buildup of aqueous fluid within the eye which can lead to visual field loss and optic nerve damage, usually without any associated pain or discomfort. The increased IOP is secondary to an imbalance between aqueous fluid secretion and fluid outflow despite an open angle. Nearly 40% of those with otherwise characteristic POAG may not have elevated IOP measurement. 6 Established risk factors for OAP include older age, African American or Latino/Hispanic ethnicity, family history of glaucoma, type 2 diabetes and underlying eye conditions that predispose to glaucoma. 6

The Ocular Hypertension Study was a randomized controlled trial (RCT) with 1636 participants from 22 clinical centers with no evidence of glaucoma between the ages of 40 to 80 years old and IOP between 24 and 32 mmHg in 1 eye and between 21 to 32 mmHg in the other eye. Subjects were randomized to either observation or treatment with commercially available topical ocular hypotensive medications. A comprehensive eye evaluation was conducted every 6 months for 72 months. Mean ±SD reduction in IOP in the medication group was 22.5%±9.9%. The IOP declined by 4.0±11.6% in the observation group. At 60 months, the cumulative probability of developing POAG was 4.4% in the medication group and 9.5% in the observation group (hazard ratio, 0.40; 95% confidence interval, 0.27-0.59; p 7 As the only known modifiable risk factor treatment of elevated IOP to reduce risk of progression to glaucoma is considered standard of care with the goal of reduction or slowing the progression of vision loss. Elevated IOP has since been the main standard to which glaucoma treatment measures. The long-standing risk of glaucoma is progressive vision loss is the most significant outcome but challenging to use as primary outcome in studies. The SMEs emphasized the benefits of early reduction in IOP through medication or MIGS procedures to reduce or delay vision loss associated with glaucoma. They explained that reduction in IOP is currently the only intervention and is therefore the only marker in studies to date. While the outcome of progression of glaucoma is the final endpoint given the benefits of lowering IOP as reported in this study they do not feel a control group without intervention is appropriate.

A prospective, multicenter interventional cohort from the pre randomization phase of a randomized clinical trial at multiple ophthalmology clinics included 603 eyes with OAG using up to 3 glaucoma meds. IOP pressure was measured using routine medications and subsequently eligible participants underwent washout of all IOP-lowering drops and measurement was taken 2-4 weeks later off medications. The authors reported the following “The mean (SD) ON IOPs for participants using 0 (n = 102), 1 (n = 272), 2 (n = 147), or 3 (n = 82) medications were 24.2 (3.2), 17.5 (3.2), 17.2 (3.1), and 17.2 (3.1) mmHg, respectively. Patients not using medication had a mean (SD) IOP decrease of 0.2 (2.8) mmHg at the OFF visit. Patients using 1, 2, and 3 medications had mean (SD) IOP increases of 5.4 (3.0), 6.9 (3.3), and 9.0 (3.8) mmHg, respectively, at the OFF visit. The percentages of patients with less than a 25% increase in IOP were 38%, 21%, and 13% for those using 1, 2, and 3 medications, respectively.” This study demonstrated discontinuation of medication resulted in a clinically significant increase in IOP especially the first medication period of proportion of patients only saw small change in IOP after the washout suggesting they were not using the medication properly or they were not working for that patient. 8 This is a significant factor in study design for studies looking at IOP reduction as the primary endpoint since a lack of a washout can limit the detection of the complete surgical effect in terms of IOP reduction. Additionally, a higher baseline IOP can lead to overestimation of the real IOP reduction.

The goal of treatment in POAG is to reduce the IOP to slow the progression of optic nerve damage and associated vision and visual field loss. The IOP can be reduced by medical treatment or surgery, alone or in combination. IOP >21 mmHg has been shown to increase rates of visual field loss. However, because of the differences in susceptibility to pressure-related disc damage among POAG patients, pressure-lowering treatments are aimed at achieving a lower “target” pressure individualized to each patient’s baseline IOP in which glaucomatous damage occurred. AAO Guidelines state that although medical management is the most common initial intervention to lower IOP in patients with glaucoma, there are many options to consider, including a variety of surgical interventions. Further, the effectiveness, potential side effects, tolerance of medications, and desired target IOP must all be balanced for each individual patient when choosing a regimen best suited for that patient, whether medical or surgical. 9