These devices, when FDA approved, are covered for patients with glaucoma that is not adequately controlled with medical therapy.

Transcription

1 Medical Policy Title: Aqueous Shunts and ARBenefits Approval: 10/26/2011 Devices for Glaucoma Effective Date: 01/01/2012 Document: ARB0168 Revision Date: Code(s): 66174, Transluminal dilation of aqueous outflow canal; without retention of device or stent 66175, Transluminal dilation of aqueous outflow canal; with retention of device or stent 66180, Aqueous shunt to extraocular reservoir 0191T, Insertion of anterior segment aqueous drainage device, without extraocular reservoir; internal approach, into the trabecular meshwork 0192T, Insertion of anterior segment aqueous drainage device, without extraocular reservoir; external approach Public Statement: Administered by: Glaucoma surgery is intended to reduce intraocular pressure (IOP) when the target IOP cannot be reached with medications. Due to complications with established surgical approaches such as trabeculectomy, a variety of devices, including aqueous shunts and transluminal dilation procedures, are being evaluated as alternative surgical treatments for patients with glaucoma. These devices, when FDA approved, are covered for patients with glaucoma that is not adequately controlled with medical therapy. Medical Policy Statement: 1) Insertion of aqueous shunts approved by the U.S. Food and Drug Administration (FDA) as a method to reduce intraocular pressure in patients with glaucoma where medical therapy has failed to adequately control intraocular pressure is considered medically necessary and is covered. 2) Canaloplasty is covered only for patients with chronic primary open-angle glaucoma when: a. Medical therapy has failed to adequately control intraocular pressure, AND b. The patient is not a candidate for any other intraocular pressure lowering procedure due to a high risk for complications. Page 1 of 8

2 3) For any other indications, use of an aqueous shunt or canaloplasty is considered investigational and is not covered. Use of shunts to reduce intraocular pressure in patients with glaucoma where medical therapy is adequately controlled by medication is considered investigational and is not covered. Background: Surgical procedures for glaucoma aim to reduce intraocular pressure (IOP) resulting from impaired aqueous humor drainage in the trabecular meshwork and/or Schlemm s canal. In the primary (conventional) outflow pathway from the eye, aqueous humor passes through the trabecular meshwork, 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 and/or the inner wall of Schlemm s canal can disrupt the balance of aqueous humor inflow and outflow, resulting in an increase in IOP and glaucoma risk. Surgical intervention may be indicated in patients with glaucoma when the target IOP cannot be reached pharmacologically. Trabeculectomy (guarded filtration surgery) is the most established surgical procedure for glaucoma, allowing aqueous humor to directly enter the subconjunctival space. This procedure creates a subconjunctival reservoir, which can effectively reduce IOP, but commonly results in filtering blebs on the eye, and is associated with numerous complications (e.g., leaks or bleb-related endophthalmitis) and long-term failure. Other surgical procedures (not addressed in this policy) include trabecular laser ablation, deep sclerectomy, which removes the outer wall of Schlemm s canal and excises deep sclera and peripheral cornea, and viscocanalostomy, which unroofs and dilates Schlemm s canal without penetrating the trabecular meshwork or anterior chamber. More recently the Trabectome, an electrocautery device with irrigation and aspiration, has been used to selectively ablate the trabecular meshwork and inner wall of Schlemm s canal without external access or creation of a subconjunctival bleb. IOP with this ab interno procedure is typically higher than the pressure achieved with standard filtering trabeculectomy. Canaloplasty involves dilation and tension of Schlemm s canal with a suture loop between the inner wall of the canal and the trabecular meshwork. This ab externo procedure uses the itrack illuminated microcatheter (iscience Interventional) to access and dilate the entire length of Schlemm s canal and to pass the suture loop through the canal. Aqueous shunts may also be placed between the anterior chamber (or vitreous chamber) and Schlemm s canal to facilitate drainage of aqueous humor. Established shunts include the Ahmed (New World Medical), Baerveldt (Advanced Medical Optics), Krupin (Eagle Vision) and Molteno (Molteno Ophthalmic). These devices differ Page 2 of 8

3 depending on explant surface areas, shape, plate thickness, the presence or absence of a valve, and details of surgical installation. Generally, the risk of hypotony is reduced with aqueous shunts in comparison with trabeculectomy, but IOP outcomes are higher than after standard guarded filtration surgery. Complications of anterior chamber shunts include corneal endothelial failure and erosion of the overlying conjunctiva. The risk of postoperative infection is less than after trabeculectomy, and failure rates are similar, with about 10% of devices failing each year. The primary indication for aqueous shunts is when prior medical or surgical therapy has failed, although some ophthalmologists have advocated their use as a primary surgical intervention, particularly for selected conditions such as congenital glaucoma, trauma, chemical burn, or pemphigoid. Other aqueous shunts are being developed as minimally penetrating methods to drain aqueous humor from the anterior chamber into an ocular reservoir. These include the istent (Glaukos), which is inserted into the end of Schlemm s canal by either an internal (through the cornea and anterior chamber) or external approach (through the subconjunctiva); the EyePass Bi-Directional Glaucoma Implant (GMP Companies), which is a Y-shaped shunt in which the 2 arms are placed ab externo into both lumina of Schlemm s canal; and the Solx DeepLight Gold Micro-Shunt (OccuLogix), which shunts aqueous humor between the anterior chamber and the suprachoroidal space. Since aqueous humor outflow is pressure dependent, the pressure in the reservoir and venous system are critical for reaching the target IOP. Therefore, some devices may be unable to reduce IOP below the pressure of the distal outflow system used, e.g., below 15 mmhg, and are not indicated for patients for whom very low IOP is desired (e.g., those with advanced glaucoma). It has been proposed that shunts may be useful to lower IOP in patients with early stage glaucoma to reduce the burden of medications and problems with compliance. One area of investigation is for patients with glaucoma who require cataract surgery. An advantage of ab interno shunts is that they may be inserted into the same incision and at the same time as cataract surgery. In addition, most devices do not preclude subsequent trabeculectomy if needed. It may also be possible to insert more than one shunt to achieve the desired IOP. Therefore, health outcomes of interest are the IOP achieved, reduction in medications, ability to convert to trabeculectomy, complications, and durability of the device. FDA-Approved/Cleared Aqueous Shunts A 2006 Cochrane review evaluated 15 randomized or pseudo-randomized controlled trials (RCTs), with a total of 1,153 participants, on the Ahmed, Baerveldt, Molteno, and Schocket shunts (Minckler, 2006). Trabeculectomy was found to result in a lower mean IOP (by 3.8 mmhg) than the Ahmed shunt at 1 year. A limitation of this report is that complications were not compared, as the authors considered them to be too variably reported to allow comparative tabulation. There was no evidence of superiority of one shunt over another. A literature review on commercially available aqueous shunts, including the Ahmed, Baerveldt, Krupin, and Molteno devices, for an American Academy of Ophthalmology (AAO) technology assessment was published in 2008 (Minckler, 2008). This review Page 3 of 8

4 indicated that the IOP will generally settle at higher levels (approximately 18 mmhg) with aqueous shunts than after standard trabeculectomy (14-16 mmhg) or after trabeculectomy with anti-fibrotic agents 5-fluoracil or mitomycin C (8-10 mmhg). In 1 study, mean IOPs with the Baerveldt shunt and adjunct medications were found to be equivalent to trabeculectomy with mitomycin C (13 mmhg). Five-year success rates for the two procedures were found to be similar (50%). The assessment concluded that aqueous shunts were comparable with trabeculectomy for IOP control and duration of benefit. The risk of postoperative infection was less with aqueous shunts than after trabeculectomy. Complications of aqueous shunts were noted to include: immediate hypotony after surgery; excessive capsule fibrosis and clinical failure; erosion of the tube or plate edge; strabismus; and, very rarely, infection. The most problematic longterm consequence of anterior chamber tube placement was described as accelerated damage to the corneal endothelium over time. Implantation of the Ex-PRESS mini shunt under a scleral flap was compared with standard trabeculectomy in a randomized study of 78 patients (80 eyes) with a diagnosis of open-angle glaucoma that could not be controlled with maximal-tolerated medical therapy (de Jong, 2009). The 2 groups were similar after randomization, with the exception of difference in the mean age (62 years for the Ex-PRESS group and 69 years for the trabeculectomy group). At an average 12 months follow-up, mean IOP had improved from 23 to 12 mm Hg in the Ex-PRESS group and from 22 to 14 mm Hg in the trabeculectomy group. Both groups of patients used fewer antiglaucoma medications postoperatively than before the procedure (from 2.8 at baseline to 0.3 in the Ex-PRESS group and from 3.0 at baseline to 0.6 in the trabeculectomy group). Twelve-month Kaplan-Meier success rates (defined as an IOP of >4 mm Hg or <18 mm Hg without use of antiglaucoma medications) were 82% for the Ex-PRESS shunt and 48% for trabeculectomy. There was a similar level of postoperative complications in the two groups. Transluminal Dilation (Canaloplasty) Lewis et al reported interim data analysis from a company-sponsored multicenter safety/efficacy study on canaloplasty using the itrack microcatheter (Lewis, 2007). Catheterization of the canal was achieved in 83 of 94 patients enrolled (88%); tension sutures were successfully placed in 74 patients (79%) with a mean IOP of 24 mm Hg. At 3-month follow-up, 57 patients (77% of 74 implanted) had an IOP of 16 mm Hg, and at 12 months 48 patients (65%) had a mean IOP of 15 mm Hg. Ten ocular adverse events (11%) were reported, including hyphema (3%), elevated IOP (3%), Descemet s membrane detachment, hypotony, choroidal effusion, and exposed closure suture (1% each). Eleven patients (12%) had a subconjunctival bleb, 6 of which resolved by 3 months. The study design included 5-year follow-up. These results were limited by the lack of randomization and high loss to follow-up. Interim 1-year results from a company-sponsored multicenter study were reported for 40 patients who had combined canaloplasty and cataract surgery (Shingleton, 2008). Page 4 of 8

5 Inclusion criteria included: a glaucoma diagnosis of primary open-angle glaucoma (POAG), pigmentary glaucoma, exfoliation glaucoma, or POAG with narrow but not occludable angles after laser iridectomy; a treated IOP of 16 mm Hg or higher at baseline; and a historical untreated IOP of 21 mm Hg or higher. Of the 54 eyes enrolled, successful circumferential catheterization was achieved in 44 eyes (81%) and sutures were successfully placed in 40 eyes (74%). The 14 eyes (26%) that did not have sutures placed were due to the microcatheter entering a collector channel or meeting other resistance during catheterization; successful suture placement was reported to increase with surgeon experience. Two eyes were considered failures, with 1 conversion to trabeculectomy. Clinical results were reported for 25 patients (46% of 54) who were both due for and reported for 12-month follow-up. Of these, 3 eyes (12%) had low subconjunctival blebs at 12 months. No case of suture erosion through the trabecular meshwork or sclera was noted during follow-up. IOP was reduced from a mean of 24 mm Hg to 13 mm Hg at 6 months (reported for 42 eyes; 40 were reported to be successfully treated) and remained under 14 mm Hg in the 25 patients who were evaluated at 12 months. The number of antiglaucoma medications decreased from a mean of 1.5 medications to a mean of 0.1 at 1 month and 0.2 at 12 months. This trial is ongoing, and longer follow-up on a larger number of patients is needed. The American Academy of Ophthalmology (AAO) published a 2008 technology assessment on commercially available aqueous shunts, including the Ahmed, Baerveldt, Krupin, and Molteno devices (Minckler, 2008). The assessment indicated that in general, the IOP will settle at higher levels (approximately 18 mm Hg) with shunts than after standard trabeculectomy (14 16 mm Hg). Five year success rates of 50% have been found for the two procedures, indicating that aqueous shunts are comparable with trabeculectomy for IOP control and duration of benefit. (based on level I evidence; well-designed randomized controlled trials). The assessment indicated that although aqueous shunts have been generally reserved for intractable glaucoma when prior medical or surgical therapy has failed, indications for shunts have broadened (based on level III evidence; case series, case reports, and poor-quality case-control or cohort studies). The AAO concluded that based on level I evidence, aqueous shunts offer a valuable alternative to standard filtering surgery or to cyclodestructive therapy for many patients with refractory glaucoma. Summary Randomized controlled trials have shown that the use of shunts results in success rates at least as good as standard filtering surgery, with similar complication rates. Other studies have reported use of shunts in patients with both cataracts and less advanced glaucoma, where the IOP is at least partially controlled with medication. Results from these studies indicate that IOP may be lowered below baseline with decreased need for medication in some patients, but complications may lead to trabeculectomy within 6 months in a number of eyes. Since it cannot be determined whether trabeculectomy would have been required had these patients remained on medical therapy, randomized controlled trials with longer follow-up are needed to Page 5 of 8

6 compare clinical outcomes from patients who have undergone cataract surgery combined with device placement or with continued medical management. In addition, the Trabectome study group reports that 3% of patients required subsequent glaucoma surgery following combined Trabectome/cataract surgery in a large series (Francis, 2008) (Minckler, 2008). Lewis et al. reported 2-year and 3-year results from the multicenter study in 2009 and 2011, respectively (Lewis, 2009) (Lewis, 2011). Enrolled in the follow-up study were 157 patients with a diagnosis of primary open-angle glaucoma, pigmentary glaucoma, exfoliative glaucoma, and a baseline IOP of 16 mm Hg or higher before surgery, with a historical IOP of 21 mm Hg or higher. Exclusion criteria were neovascular disease, uveitis, peripheral anterior synechiae, angle recession, and developmental or secondary glaucoma (except for pigmentary and exfoliative glaucoma). At baseline, the mean IOP was 23.8 and patients were on an average 1.8 medications; 21% of eyes were on 3 or more antiglaucoma medications, and 12 eyes (7.6%) were on no medications. Twentyfive eyes (15.9%) were pseudophakic. Canaloplasty (with or without cataract surgery) was successful in 133 eyes (85%). Eyes that did not have placement of a tensioning suture were viscodilated to the extent possible by catheterizing the canal from both ostia. At 3 years postoperatively, 134 study eyes (85% follow-up) had a mean IOP of 15.2 mm Hg and mean glaucoma medication use of 0.8 medications; 4 eyes (3%) were on 3 or more antiglaucoma medications, and 66 eyes (49.3%) were on no medications. Another 7 patients (4.4%) had additional glaucoma surgery. Six eyes lost 2 or more lines of corrected visual acuity related to glaucoma progression. With qualified success defined as achieving IOP of 18 mm Hg or lower (with 0 to 2 medications), success was achieved in 69 of the 89 eyes (77.5%) that had successful suture implantation alone and 24 of the 27 eyes (89%) with successful suture placement combined with phacoemulsification. Early surgical/postoperative complications included microhyphema (12%), hyphema (10%), elevated intraocular pressure (6%), Descemet membrane detachment (3%), suture extrusion (1%), and hypotony (1%). Late postoperative complications included cataract (12.7%), transient IOP elevation (6.4%), and partial suture extrusion through the trabecular meshwork (0.6%). Koerber et al. reported on 15 of the patients who participated in the multicenter trial described above who had bilateral POAG and received canaloplasty in one eye and viscocanalostomy in the contralateral eye (Koerber, 2011). Qualifying preoperative IOPs were 18 mm Hg or greater with historical IOPs of at least 21 mm Hg. For the canaloplasty eye, the baseline IOP averaged 26.5 mm Hg on 2.1 medications. All patients had successful suture placement. Follow-up at 18 months showed IOP of 14.5 on 0.3 medications. For the viscocanalostomy eye, the baseline eye averaged 24.3 mm Hg on 1.9 medications; follow-up at 18 months showed an average IOP of 16.1 on 0.4 medications. The reduction in IOP from baseline was significantly greater with canaloplasty (12.0 mm Hg) than with viscocanalostomy (8.2 mm Hg). There was no loss in visual acuity and no adverse events from either procedure. The authors noted that this study effectively compares the additional effects of the 2 major additional maneuvers associated with canaloplasty: first, 360 degrees viscodilation of Schlemm s Page 6 of 8

7 canal, as opposed to partial dilation achieved with viscocanalostomy, and second, prolonged opening and tensioning of Schlemm s canal with suture placement. Grieshaber et al. reported a prospective series of 60 consecutive black South African patients with POAG who underwent canaloplasty (Grieshaber, 2010). The mean preoperative IOP was 45 mm Hg. At 12 month follow-up, the IOP was 15 mm Hg (n=54), and at 36 months, the IOP was 13.3 mm Hg (n=49). Eleven patients (18%) were lost to follow-up at 3 years. With qualified success defined as achieving IOP of 21 mm Hg or lower (with or without medications), success was achieved in 40 of 49 patients (82%). When defined as an IOP of 16 mm Hg or less without medications, 47% of eyes met criteria for complete success. There were no severe complications in this series. Mosaed and colleagues published a comparative effectiveness review of newer (Trabectome and canaloplasty) and older (trabeculectomy and Baerveldt shunt) surgeries for glaucoma in 2009 (Mosaed, 2009). Twelve-month outcomes (intracocular pressure adjunctive medications and complications) were compared after glaucomaonly and combined glaucoma-phacoemulsification surgeries. The review found that Trabectome and canaloplasty provided modest IOP reduction (to about 16 mm Hg) with minimal intraoperative or postoperative complications. Results of Baerveldt glaucoma implant IOP reduction were comparable to trabeculectomy (about 12 mm Hg), but typically this shunt required more postoperative IOP-lowering medication (average of 1.3 vs. 0.5 medications, respectively) to achieve a success rate comparable to trabeculectomy. Patients treated with Trabectome required more medications (average of 1.5) to control IOP than patients treated with canaloplasty (average of 0.6). The authors concluded that Trabectome and canaloplasty are reasonable surgical therapy choices for patients in which IOPs in the mid-teens seem adequate; although trabeculectomy remains the most effective IOP-lowering procedure, it also has the highest serious complication rates. References: de Jong LA.(2009) The Ex-PRESS glaucoma shunt versus trabeculectomy in open-angle glaucoma: a prospective randomized study. Adv Ther 2009; 26(3): Dietlein TS, Jordan JF, Schild A et al.(2008) Combined cataract-glaucoma surgery using the intracanalicular Eyepass glaucoma implant: first clinical results of a prospective pilot study. J Cataract Refract Surg 2008; 34(2): Francis BA, Minckler D, Dustin L et al;(2008) Trabectome Study Group. Combined cataract extraction and trabeculotomy by the internal approach for coexisting cataract and open-angle glaucoma: initial results. J Cataract Refract Surg 2008; 34(7): Grieshaber MC, Pienaar A, Olivier J et al.(2010) Canaloplasty for primary open-angle glaucoma: long-term outcome. Br J Ophthalmol 2010; 94(11): Koerber NJ.(2011) Canaloplasty in One Eye Compared With Viscocanalostomy in the Contralateral Eye in Patients With Bilateral Open-angle Glaucoma. J Glaucoma Lewis RA, von Wolff K, Tetz M et al.(2007) Canaloplasty: circumferential viscodilation and tensioning of Schlemm's canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults: interim clinical study analysis. J Cataract Refract Surg 2007; 33(7): Lewis RA, von Wolff K, Tetz M et al.(2009) Canaloplasty: circumferential viscodilation and tensioning of Schlemm canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults: two-year interim clinical study results. J Cataract Refract Surg 2009; 35(5): Lewis RA, Von Wolff K, Tetz M et al.(2011) Canaloplasty: Three-year results of circumferential viscodilation and tensioning of Schlemm canal using a microcatheter to treat open-angle glaucoma. J Cataract Refract Surg 2011; (in press). Minckler D, Mosaed S, Dustin L et al;(2008) Trabectome Study Group. Trabectome (trabeculectomy-internal approach): additional experience and extended follow-up. Trans Am Ophthalmol Soc 2008; 106: Page 7 of 8

8 Minckler DS, Francis BA, Hodapp EA et al.(2008) Aqueous shunts in glaucoma: a report by the American Academy of Ophthalmology. Ophthalmology 2008; 115(6): Minckler DS, Vedula SS, Li TJ et al.(2006) Aqueous shunts for glaucoma. Cochrane Database Syst Rev 2006; (2):CD Mosaed S, Dustin L, Minckler DS.(2009) Comparative outcomes between newer and older surgeries for glaucoma. Trans Am Ophthalmol Soc 2009; 107: Shingleton B, Tetz M, Korber N.(2008) Circumferential viscodilation and tensioning of Schlemm canal (canaloplasty) with temporal clear corneal phacoemulsification cataract surgery for open-angle glaucoma and visually significant cataract: one-year results. J Cataract Refract Surg 2008; 34(3): Spiegel D, García-Feijoó J, García-Sánchez J et al.(2008) Coexistent primary open-angle glaucoma and cataract: preliminary analysis of treatment by cataract surgery and the istent trabecular micro-bypass stent. Adv Ther 2008; 25(5): Spiegel D, Wetzel W, Haffner DS et al.(2007) Initial clinical experience with the trabecular micro-bypass stent in patients with glaucoma. Adv Ther 2007; 24(1): Application to Products This policy applies to ARBenefits. Consult ARBenefits Summary Plan Description (SPD) for additional information. Last modified by: Date: Page 8 of 8