Effects of a rapamycIn-eluting carboNized Stent With a Completely biodEgradable polymeR Coating on inflammaTory Biomarkers and Endothelial Damage

Percutaneous coronary intervention with stenting may induce endothelial damage/dysfunction and inflammatory reactions, which in turn delay healing and endothelialization and may lead to the occurrence of major adverse cardiac events (MACE), such as restenosis, atherosclerosis, and stent thrombosis.

Drugs, platforms and polymers are considered the protagonists of these pathophysiologic processes.

Platforms Due to advances in stent technology, several stent platforms are now available, including the stainless steel, the cobalt-chromium, and the platinum-chromium stent series. Pre-clinical animal studies suggest that some platforms might have important advantages in terms of vascular compatibility and early and late healing. In a rabbit denudation model, it was shown that at 14 days the luminal surface area is incompletely endothelialised with the CrCo stents but nearly complete for other metals. Additionally, it has been shown that a thinner-strut stent is associated with reduced fibrin deposition and more rapid fibrin clearance in porcine coronary arteries compared with thicker stents, thus suggesting that the thin stent platforms may induce less injury. As a matter of fact, The second-generation DESs, with thinner struts, are obviously associated with a suppression of the neointimal response and a more rapid re-endothelialization but stainless steel based stent design might have a better conformability to the vessel wall which results to less malposition.

Polymers The polymer coating that elutes the antiproliferative drug has been linked to complications including delayed vessel healing, hypersensitivity reactions, atheroma, and restenosis, with the potential for repeat intervention, stent thrombosis, acute myocardial infarction, and sudden death.

The link between the permanent polymer and late adverse events has prompted the development of a variety of biodegradable polymer coatings. Absorption of the polymer may lower the rates of stent thrombosis, particularly beyond 1 year after stent implantation. In addition, stents with absorbable polymers may allow a shorter duration of dual antiplatelet therapy (DAPT) than currently recommended The incidence of late adverse events is likely to be lower after the absorption of the polymer than after the implantation of drug-eluting stents coated with a permanent polymer, as there is less ongoing inflammation than with permanent polymers. In a meta-analysis of randomized trials, metal stents that release an antiproliferative drug from an absorbable polymer coating had lower rates of MACE out to 4 years than metal stents that released a drug from a durable polymer. The randomized LEADERS (Limus Eluted from A Durable versus ERodable Stent) trial studies showed that a biolimus eluting stent coated with a biodegradable polymer had a lower risk of adverse cardiac events associated with very late ST through 5 years of follow-up, improving the long-term clinical outcomes compared with sirolimus-eluting stents coated with a durable polymer