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Biodegradable StentsFuture Solutions
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Coronary Stents Design Part C – Biodegradable stents and Future Solutions
Dr. Amir Kraitzer
The contents of materials available on this presentation are reserved. Content may not be reproduced, published, or transferred except with the prior written permission of Dr. Amir Kraitzer
Biodegradable Stents (BDS)
Rational for Biodegradable stents
Metal stent drawbacks Cause permanent physical
irritation Risk of long term endothelial
dysfunction and chronic inflammation
Metal have thrombogenic properties
Inability for the vessel to restore its a normal physiology
Biodegradable stent advantages May eliminate early and late
complications of bare-metal stents
Restore the vasoreactivity Allow a gradual transfer of the
mechanical load to the vessel Higher capacity for drug
incorporation and complex release kinetics
Facilitate re-intervention
The need for a permanent prosthesis decreases dramatically 6 months post-implantation
Design considerations Overall time and rate of degradation
a very rapid degradation rate can be associated with inflammation
Biocompatibility of degradation products to prevent toxicity
Mechanical properties Mechanical recoil Strut size Creep Embolization of degraded particles
Drug load Radiopacity
Igaki-Tamai BDS
A bioresorbable zigzag coil design PLLA (Initial MW=183KDa) Initial clinical trial results proved
efficacy and safety (2000) On November 2007 the stent
obtained CE mark indicated for peripheral artery
Igaki Tamai Stents loaded with ST638 (Tranilast) reduced neointima formation in animals
BVS (Abbott) Drug Eluting BDS
Drug: Everolimus Base Polymer: PLLA Coating: PDLLA Releases 80% of its drug in 28 days Maintains radial strength for 3
months Mass loss after 6 months, complete
resorption in two years Good clinical outcomes with two
years follow-up No occurrence of thrombosis
between 6 and 24 months
Source: Abbott Vascular, AP2929018Rev A
Stent Functionality phases
Richard J Rapoza, PhD presented at the ICI meeting of 2009, Tel Aviv, Israel
REVA Drug Eluting BDS
Drug: Paclitaxel Base polymer: Tyrosine-
derived polycarbonate platform Low recoil (<1%) Slide and lock design Tunable resorption rate Radiopacity is achieved by the
incorporation of iodine molecules
Absorbable Magnesium Stent (Medtronic) Radial strength and recoil
is similar to BMS 4-month clinical results: late
loss is comparable to BMS Further improvement in stent
design due to: Early recoil Fast degradation Neointima formation
BDS Summary
New Concepts
Pro-healing approach Drug eluting balloon
Endothelial Progenitor Cells Capture
Genous Stent
Precilinical trials 1 hour post- deployment:
90% cell coverage 1st Clinical trial
demonstrated safety and feasibility
2nd Clinical trial demonstrated late loss is comparable to BMS
Endothelial Progenitor Cell Capture by Stents Coated With Antibody Against CD34 : The HEALING-FIM Registry, Aoki et al, J. Am. Coll. Cardiol. 2005;45;1574-1579
Drug eluting balloon
Provides uniform drug dose Reduces thrombosis risk and
enables shorter dual anti-platelet regimen
Allows significantly lower drug dose compared with DES
Two forms of release Drug and spacer Nanoparticles
SeQuent® Please
Core/shell fiber structure concept
I. Good mechanical propertiesII. Effective drug release profileIII. Porous structured coating
allows controlled release
In-Vitro FTS Release
Porous coating
Porous coating
Dense coatingDense coating
Effect of coating’s porosity
50/50 PDLGA50/50 PDLGA 75/25 PDLGA75/25 PDLGA
References
Amir Kraitzer, Yoel Kloog, Meital Zilberman, Approaches for Prevention of Restenosis, J Biomed Mater Res Part B: Appl Biomater 85B: 583–603, 2008
Gladius Lewis, Review: Materials, Fluid Dynamics, and Solid Mechanics Aspects of Coronary Artery Stents: A State-of-the-Art Review, Biomed Mater Res Part B: Appl Biomater 86B: 569–590, 2008
Meital Zilberman, Amir Kraitzer, Orly Grinberg and Jonathan J. Elsner, Drug-Eluting Medical Implants, In : Handbook of European Pharmacology, 2008
Update on Bioabsorbable Stents: From Bench to Clinical, RON WAKSMAN, Journal of Interventional Cardiology, Vol. 19, No. 5, 2006
Thank you