XEN GEL STENT - PDF Document

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  1. 4/5/2018 XEN GEL STENT OMAHA AND LINC OLN EYE AND LASER INSTITUTES MARK R. YOUNG, M.D. April 7, 2018 QUESTION: Why are we looking for alternatives to current glaucoma treatment? Look at current surgical glaucoma treatments and their drawbacks Overview of MIGS procedures  Xen Gel Stent focused review XEN45 GEL STENT WHY ARE WE LOOKING FOR NEW INNOVATIONS IN GLAUC OMA SURGERY? MIGS 1

  2. 4/5/2018 SAFETY EFFIC AC Y MIGS Where does MIGS fit in the treatment paradigm for glaucoma? MIGS MIGS MAY HAVE A ROLE IN EARLIER TREATMENT OF GLAUC OMA MEDICATIONS POOR IOP-LOWERING RESPONSE ALLERGY TO MEDIC ATION INABILITY OR POOR C OMPLIANC E WITH ADMINISTRATION UNAFFORDABLE LASER POOR RESPONSE TO TREATMENT ANGLE NOT AC C EPTABLE FOR TREATMENT GLAUCOMA MEDICATIONS AND LASER 2

  3. 4/5/2018  COMPLICATION RATES ARE RELATIVELY HIGH  50% TRANSIENT PERIOPERATIVE C OMPLIC ATIONS  ANTI-METABOLITES INC REASE C OMPLIC ATIONS  MULTIPLE POSSIBLE C OMPLIC ATIONS  SHORT-TERM  LONG-TERM  EFFICACIES OR SUCCESS RATES ARE LOWER THAN WHAT PATIENTS EXPECT  ONE STUDY: 36% FAILED TO SHOW DESIRED RESULT  50%-93% SUC C ESS RATE DEPENDING ON TYPE OF GLAUC OMA  50% SUC C ESS RATE WITHOUT ANTIMETABOLITES TRABECULECTOMY AND TUBE SHUNTS INTRAOPERATIVE  C ONJ UNC TIVAL BUTTON-HOLES  SC LERAL FLAP DEHISC ENC E  INTRAOPERATIVE BLEEDING COMPLICATIONS OF TRABECULECTOMY POSTOPERATIVE EARLY HYPOTONY DUE TO OVER-FILTRATION AQUEOUS MISDIREC TION BLEB DYSESTHESIA EARLY OR LATE BLEB LEAK BLEB FAILURE BLEB-RELATED INFEC TION/ENDOPHTHALMITIS COMPLICATIONS OF TRABECULECTOMY 3

  4. 4/5/2018 TRABEC ULEC TOMY C OMPLIC ATIONS OVERFILTRATION TRABEC ULEC TOMY C OMPLIC ATIONS WOUND LEAK TRABEC ULEC TOMY C OMPLIC ATIONS BLEBITIS 4

  5. 4/5/2018  EARLY HYPOTONY  TUBE OC C LUSION  ELEVATED IOP  SHUNT EXPOSURE/EXTRUSION  C ORNEAL DEC OMPENSATION  IRIS TOUC H/INFLAMMATION  ENDOPHTHALMITIS COMPLICATIONS OF TUBE SHUNTS TUBE SHUNT COMPLICATIONS TUBE EXTRUSTION  THE SAFETY OF MIGS IS WELL DOCUMENTED  IMPROVING EFFICACY IS THE GOAL  MEGS  STRATEGIC ALLY PLAN AND TARGET AREAS OF OUTFLOW  LOOKING FOR AREAS OF LOWER RESISTANC E  SC HLEMM’S C ANAL MAY NOT BE C ONTINUOUSLY OPEN  STENTS MAY BE PLAC ED AWAY FROM C OLLEC TOR C HANNELS  C OLLEC TOR C HANNELS MAY HAVE THEIR OWN RESISTANC E  SUPRAC HOROIDAL AND SUBC ONJ UNC TIVAL SPAC E HAVE LOW RESISTANC E MINIMALLY INVASIVE GLAUCOMA SURGERY (MIGS) 5

  6. 4/5/2018 BEING MINIMALLY INVASIVE, IF THE MIGS PROC EDURE FAILS, THE TISSUE HAS BEEN PRESERVED, SO THAT MORE INVASIVE SURGERY C AN STILL BE DONE (TRABEC ULEC TOMY OR TUBE SHUNT) MIGS 3 MIGS OUTFLOW TARGETS: SC HLEMM’S C ANAL SUPRAC HOROIDAL SPAC E SUBC ONJ UNC TIVAL SPAC E MIGS iSTENTBY GLAUKOS iSTENTINJ ECT BY GLAUKOS HYDRUS BY IVANTIS SCHLEMM’S CANAL STENTS AND SURGICAL PROCEDURES 6

  7. 4/5/2018 CYPASS BY TRANSC END iSTENT SUPRA BY GLAUKOS SUPRACHOROIDAL SPACE STENTS AqueSys XEN 45 Gel Stent SUBCONJ UNCTIVAL STENT AQUEOUS OUTFLOW 7

  8. 4/5/2018 Conventional = Trabecular meshwork/Schlemm’s canal/Aqueous veins/Episcleral veins Pressure dependent 85-95% of drainage Adrenergic agonists and mioticsincrease Prostaglandins increase pulse wave AQUEOUS OUTFLOW IS THE DISTAL OUTFLOW SYSTEM REGULATED, AND DOES IT HAVE ITS OWN RESISTANCE? WHY DOESN’T TRABECTOME SURGERY DROP THE IOP TO EPISCLERAL VENOUS PRESSURE? C ONVENTIONAL OUTFLOW POSSIBE REASONS WHY TRABECTOME DOES NOT LOWER IOP TO EPISCLERAL VENOUS PRESSURE: Autoregulation – TM not present to open hinged scleral flaps in collector channels Extrinsic regulation – neural or endocrine signal to increase resistance in untreated angle structures OUTFLOW REGULATION 8

  9. 4/5/2018 ? DOES THE CONVENTIONAL OUTFLOW SYSTEM HAVE AUTOREGULATION AND EXTRINSIC REGULATION LIKE THE REST OF OUR VASCULAR SYSTEM? AQUEOUS OUTFLOW Understanding the complexity of the conventional outflow system may help us in treatment Unfortunately, this same complexity may preclude any straightforward or simple treatment in this pathway Several treatments at different sites may be required OUTFLOW REGULATION AND FEEDBAC K LOOPS It is possible the best treatment IOP we can achieve through this pathway will be mid-teens, due to the regulatory feedback loops To achieve lower pressures , we will probably need to bypass this pathway to the supra-choroidal or subconjunctival spaces OUTFLOW REGULATION AND FEEDBAC K LOOPS 9

  10. 4/5/2018 SUBCONJ UNCTIVAL STENT XEN GEL STENT Stand alone procedure MIGS AQUESYS XEN45 GEL STENT AQUESYS XEN45 GEL STENT 10

  11. 4/5/2018 DR. YOUNG’S RESULTS 11 eyes of 10 patients 5 right eyes, 6 left eyes Average pre op IOP: 23 mmHg (13-39) Average pre op drops: 1.6 Average post op IOP (1Month): 16.2 mmHg Average post op IOP (3 Months): 13.9 mmHg Average post op drops: .3 XEN GEL STENT CONSIDERATIONS WITH XEN Learning curve Patient selection Young patients Thick Tenon’s capsule Scar formers Desired level of placement in Tenon’s capsule Amount and location of intraoperative mitomycin XEN GEL STENT CONSIDERATIONS WITH XEN Surgical manipulation of curled stent Postoperative medications and duration Postoperative manipulation of stent Postoperative mitomycin and needling procedures Bleb management Massage XEN GEL STENT 11

  12. 4/5/2018 CONSIDERATIONS WITH XEN COMPARED WITH TRABECULECTOMY Xen procedure is not as traumatic, but trabs will have lower pressures Extensive dissection with trab allows for larger, more diffuse blebs Xen still requires close bleb management for at least 3 months after surgery XEN GEL STENT CONSIDERATIONS WITH XEN COMPARED TO TRABECULECTOMY Whereas with the achievable IOP with trabeculectomy and mitomycin is 10 or less, the achievable IOP with Xen is probably going to be higher, as in the low- teens XEN GEL STENT INDICATIONS FOR XEN Primary open angle glaucoma with less than adequate control After medication and selective laser trabeculoplasty options have been exhausted Allergies to, or intolerance for, or poor compliance with, medications Possible step before the more invasive trabeculectomy or tube shunt procedures XEN GEL STENT 12

  13. 4/5/2018 POSSIBE EXPANDED USE OF XEN: Pigmentary or PXE glaucoma Steroid responders Prolonged post-op IOP elevation Inflammatory glaucoma (PAS) Neovascularglaucoma Lowering IOP before corneal transplant After failed trabeculectomy MIGS Conclusions: We need a more safe and efficacious way to perform glaucoma surgery C urrent surgeries have unacceptably high complication and failure rates MIGS procedures offer safety, but as yet have not been shown to lower IOP sufficiently MIGS using Schlemm’s canal as target have only a modest IOP-lowering effect, possibly due to resistance in the canal or collector system MIGS Autoregulation and Extrinsic Regulation of aqueous production and outflow may be similar to other vascular loops in the body Distal outflow resistance in the collector channels may play a more important role than previously realized CONCLUSIONS 13

  14. 4/5/2018 The complexity of the conventional outflow system may preclude an easy treatment algorithm Mid-teens may be all we can achieve in treatment through this outflow pathway Other low-resistance targets with less complexity may result in lower IOP CONCLUSIONS Conclusions: MIGS procedures using lower resistance targets may be the answer to lowering intraocular pressure Suprachoroidal space Subconjunctival space XEN GEL STENT MIGS may have expanded use besides POAG MIGS Learning curve is fairly steep Patient selection is important C orrect placement of stent is critical to success Intraoperative and postoperative mitomycin are utilized XEN CONCLUSIONS 14

  15. 4/5/2018 Surgical and postoperative manipulation of stent may be required Bleb management still required for at least 3 months after surgery Less traumatic than trabeculectomy, but final pressures will be higher Expect final pressures in low teens with Xen procedure XEN CONCLUSIONS XEN GEL STENT OMAHA AND LINC OLN EYE AND LASER INSTITUTES MARK R. YOUNG, M.D. April 7, 2018 15

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  19. 4/5/2018 AmbioDisc (Freeze Dried) Mixed Results Prokera (Cryopreserved) Effectiveness Consistent Results Cost $500-600 $600-700 Ease of Use User friendly, but requires Lid Speculum and Forceps Comparable to placing BCL Patient Comfort Comparable to BCL Polycarbonate Ring can be poorly tolerated Storage Room temperature Requires a Freezer ~4C 4

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