Drug-Eluting Stents
Stents are tiny wire-mesh tubes made of surgical grade stainless steel, cobalt chromium, or other metal alloys designed to keep arteries open. The stent material is not native to the body and its presence in a vascular environment incites an immune response. This response often demonstrates itself in abnormal cell proliferation resulting in the scar tissue excessively overgrowing the stent. Additionally, blood clots may form. Hence, as a routine procedure the patients must take antiplatelet drugs, such as clopidogrel together with aspirin which has known anticoagulant properties. Since patients receiving stents remain at risk for the aforementioned problems, doctors continue to explore more efficient and longer-lasting stenting solutions. One of the more effective methods involves employing stents that are covered with medicines that can be released once inside the body. The so called drug-eluting stents carry and may release anti-proliferative and anti-inflammatory drugs or immunosuppressant’s. To lessen this problem of excessive tissue re-growth or in-stent restenosis (re-narrowing), and reduce the need for revascularization.
Drug-eluting stents successfully counter measured post-deployment inflammatory reactions and considerably reduced the incidence of restenosis to only approximately 8% from 25% experienced with leading “bare metal” stents. Drug-eluting stents have become, after approximately one year on the market, the most widely used modality for coronary revascularization. More than three million heart patients received drug eluting stents since their introduction. Drug-coated stents, which cost about $2,000 - $2,300 per stent, generated $5.3 billion in sales last year alone, in a field dominated by Boston Scientific Corp. and Johnson & Johnson. More recently the uncoated, “bare metal” stents, which sell for about $700 also experienced growth in demand, due to the concerns related to the long term effectiveness of drug eluting stents and the cases of clotting (late thrombosis) attributed to the presence of polymers which trigger the reaction of the body immune system to their imperfect biocompatibility .
All MIVT’s HAp based surface modifications and drug delivery systems are completely polymer-free and extremely thin ranging from 150 nanometers to 700 nanometers. At 700 nanometers or 0.7 microns MIVT drug-eluting coatings are over 10 times thinner than the coatings found on today’s leading drug-eluting stents. When combining MIVT drug-eluting coatings with the GenX Thin Strut Stent the total strut thickness is less than 66 microns over 30% thinner than Medtronic’s Endeavor (96 microns) and over 25% thinner than Abbott’s Xience V (89 microns). When combined with the GenX stent the total strut thickness is 106 microns which not only compares favorably with the Endeavor and the Xience V but is meaningfully thinner than other leading drug eluting stainless steel stents such as Boston Scientific’s Taxus Liberte’ (148 microns) and Johnson and Johnson’s Cypher (154 microns). MIVT proprietary technologiesh match biocompatibility with deliverability, flexibility and optimal drug release and delivery and should provide an attractive alternative to today’s polymer based drug eluting stents.
