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ENDOVASCULAR FEMORAL STENTS CAN WE RELY ON LONG-TERM FRIENDSHIP ?

ENDOVASCULAR FEMORAL STENTS CAN WE RELY ON LONG-TERM FRIENDSHIP ?. Cairo - EGYPT. Emad A Hussein ; MD. Ain Shams University. Emad A Hussein ; MD. Vascular Surgery Department. ENDOVASCULAR FEMORAL STENTS CAN WE RELY ON LONG-TERM FRIENDSHIP ?. Emad A Hussein ; MD

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ENDOVASCULAR FEMORAL STENTS CAN WE RELY ON LONG-TERM FRIENDSHIP ?

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  1. ENDOVASCULAR FEMORAL STENTS CAN WE RELY ON LONG-TERM FRIENDSHIP ? Cairo - EGYPT Emad A Hussein ; MD Ain Shams University Emad A Hussein ; MD Vascular Surgery Department

  2. ENDOVASCULAR FEMORAL STENTS CAN WE RELY ON LONG-TERM FRIENDSHIP ? Emad A Hussein ; MD Vascular Surgery Department Ain Shams University Cairo – EGYPT MUSCAT ; OMAN IVC - March 2013

  3. STENT • “ A device that supports against collapse or deformity “ ENDOLUMINAL STENT • The stent is carried by a catheter to a remote site inside the lumen

  4. endovascular support

  5. Use of metallic stents in Surgery BACK TO 16th CENTURY ( Gold in dentistry ! )

  6. ENDOVASCULAR STENTSCURRENT STUATION • 70-85 % of coronary interv.(>1million/yr) • 25-35 % of peripheral interv. ( Thierry; J Endovasc Ther 2003 ) • > 50 types of stents/stent- grafts  FDA • Worldwide market $ 2.5 billion • Annual Growth rate 5 %

  7. ENDOVASCULAR STENTSCURRENT SITUATION RESTENOSIS RATE • 8-10 % for ideal lesions • 30-50 % for complex lesions esp. diabetics ( Gershlick; Heart 2004)

  8. INDICATIONS OF STENTING • 1- Sub optimal PTA / Complex lesions • 2- Recurrent stenoses post-PTA • 3-To fix a PTA complication ; Bail-out ( Dissection , Thromb., Perf. )

  9. Where can stents be used ? Nonvascular - Ureter Bronchial Biliary • Trachea • Oesophagus • Vascular - Coronary arteries - Coronary vein bypass - A. carotid - A. subclavian - A. Renal - TIPPS - Aorta - Dialysis Fistula - A. iliac - A. femoral - Veins - Vena cava sup. syndrome - Vena cava inf. syndrome - Pulmonary stenosis

  10. STENTS - CLASSIFICATION Stent ( Bare )Material • Manufacture Shape& Design • Mode of Deployment • Rate of Compliance • Special Types(Covered & Drug Eluting )

  11. Balloon expandable stents • Production usually out of a pipe tube • Cutting of the design through • - Laser cutting (cleanest technology) • - Water jet technology • Other cutting techniques

  12. Balloon expandable stents Advantages: • - Balloon exp. is a known mechanism • - clear radiopacity • - precise placement • - high radial force Disadvantages: • - no self expansion (deformable from outside) • - may be too rigid. ? CRUSHABILITY • - may not be flexible enough.

  13. Self expandable stents • Material usually nitinol - different stents on the market:Memotherm, Sinus-Stent, Cragg-Stent, Vascucoil, S.M.A.R.T. • Exception mediloy/cobalt alloy - Wallstent

  14. Self expandable stents • Advantages: - Flexible - stable Form, not deformable - Self expansion (own force) • Disadvantages: - Misplacement is often criticized - Lower radial force

  15. S.M.A.R.T.Control Stent Characteristics • Nitinol • Lasercut,electropolished • Multisegmented Design • Micromesh Geometry • Micromarkers • Minimal Foreshortening • Clinical Results

  16. Perfect Wall apposition with self expandable stent S.M.A.R.T. Control Wallstent

  17. WHICH STENT FOR WHICH LESION ? • Site ( anatomy ) - Kinking, Ostial stnosis etc.. • Carotid & fempop  Self exp • Renal  Balloon exp ( ostial ) • Aorto-iliac  Balloon or self exp Morphology - Calcified plaques, recoiling - Exact placement ( close import.branch etc..)

  18. FURTHER FACTS ABOUT STENTS • Bio stability • Bio compatibility Available data derived • In-stent thrombosis from in-vitro testing ! • In-stent stenosis 1ry & 2ry Patency ( Not only technique dependant ! )

  19. Patency Rates Nitinol Stents - Fempop

  20. AIN SHAMS UNIVERSITYVASCULAR SURGERY . 2001-2012 Demerdash + Specialized Hospital Stents Deployed – Balloon / Self Exp. Iliac 143 Fempop 132 ( including 5 hemo / viabahn ) Tibial 33 ( CLLI-Limb salvage ) Renal 16 + Carotid 17 ( short-term F.U ) Venous 39

  21. AIN SHAMS UNIVERSITY VASCULAR SURGERY . 2001-2012 • 2010 …. To Date IN FEMOROPOP SEGMENT • MORE DEB & LESS STENTS !

  22. AIN SHAMS UNIVERSITY VASCULAR SURGERY . 2001-2012 STENT REGISTRY • Follow-up non uniform ( & so is patency ! ) • Range 4-46 months • Different complications ( Restenosis/ Thromb./ Migration / Fr ? ) Occurring 8 months – 3 years • Determinant Factor ( ? Multifactorial )

  23. AIN SHAMS UNIVERSITYVASCULAR SURGERY . 2001 – 2012 STENT REGISTRY ( Femoropop ) • Total 127 All Self-Exp + 5 Hemobahn / Viabahn • Occlusions93 Stenoses 39 • 1ry Patency ( 3 yrs ) 87 % • Lesion length 1.8 – 17.7 cm

  24. AIN SHAMS UNIVERSITYVASCULAR SURGERY . 2001 – 2012 STENT REGISTRY ( Femoropop ) Stent Fracture 2 ( Lesion > 9 cm ) In Stent Thrombosis 4 ( 3 % ) In Stent Stenosis 6 ( 4.6 % ) – Migration 1 Mortality ( unrelated / MI or CVA ) 3

  25. FINAL RESULT POST-STENT

  26. THE PROBLEM WITH STENTS ? • Metal inside blood vessels  permanent • ? Body reaction Chemical + Mechanical Factors WHAT HAPPENS IN A FEW YEARS ? To stent To artery To body

  27. IN ALL STENTS ( including Nitinol ) • Pitting Corrosion • Fractures • ?Allergy • Degradation Products Pro inflammatory effects commonly associated with RESTENOSIS !

  28. F D A ( 2006 / 2007 ) • “ Long – term biodegradation of metallic devices remains a serious issue ! “

  29. BIO STABILITY Are Alloys used in Endovascular Surgery STABLE ? • Stainless Steel / Nitinol / Elgiloy / Tantalum • All release +ve ions ( esp.nickel ) & liable to pitting corrosion but by the process of passivation (electropolishing ) ion release esp.nitinol ( 75 % less )

  30. BIO STABILITY ? FURTHER COMPOUND PROBLEM Physiologic Body Fluids Contain : • Dissolved O2 • Chloride/ Hydroxide /Sodium • Potassium/ Bicarb/ Phosphate • Magnesium/ Calcium ions VERY CORROSIVE ELECTROLYTES !

  31. BIO COMPATIBILITY “ Blood-Device Surface Interaction “ OR Biologic Response to Degradation Products

  32. BIO COMPATIBILITY Stent Deployed • What happens in the 1st few seconds ?

  33. BIO COMPATIBILITY • Bio material  Blood • A hydration layer forms within seconds • Rapid adsorption of a layer of pl.proteins •  Triggers Cellular invasion Inflammatory response

  34. BIO COMPATIBILITY • Bare metal stents inherently thrombogenic • Rationale for adjunctive Antiplatelets + Anticoagulants • ? Metal hypersensitivity • ? Cytotoxicity & Carcinogenicity ( concern in orthopedic implants )

  35. NITINOL STENT FRACTURE ? • SIROCCO 1 Trial - Cordis  18.2 % ( Duda SH et Al ; Circulation. 2002 ) • SIROCCO II  8 %( J Vasc Interv Radiol. 2005 ) Long segment SFA Stenting ; 57 pts randomized Sirolimus – Eluting vs Bare NitinolStents F.U 6 ms – Radiologic Screening In SIROCCO 1 , Longer lesions were addressed !? SIROlimus Coated COrdis Self Expandable Stent

  36. NITINOL STENT FRACTURE • LONG SEGMENT FEMPOP NITINOL STENT ( Sabeti S et Al ; J Endovasc Ther . 2005 ) 15 % ( Scheinert B et Al ; J Am Coll Cadiol . 2005 ) 93 pts ( 121 limbs ) F.U 10.7 ms Global Stent Fracture37.2 % Stented Segment =< 8 cm 13.2 % Fr. Rate > 8 – 16 cm 42.4 % Fr. Rate

  37. 1st Study to demonstrate that • “STENT FRACTURE IS NOT A BENIGN INCIDENTAL FINDING , BUT IS ASSOCIATED WITH INCREASED RESTENOSIS“ • Kaplan Meier estimates for PATENCY at 12 ms Non-Stent Fracture  84.3 % Stent Fracture  41.1 %

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