Advantages and disadvantages of biodegradable platforms in drug eluting stents

Abstract

Coronary angioplasty with drug-eluting stent (DES) implantation is currently the most common stent procedure worldwide. Since the introduction of DES, coronary restenosis as well as the incidence of target vessel and target lesion revascularization have been significantly reduced. However, the incidence of very late stent thrombosis beyond the first year after stent deployment has more commonly been linked to DES than to baremetal stent (BMS) implantation. Several factors have been associated with very late stent thrombosis after DES implantation, such as delayed healing, inflammation, stent mal-apposition and endothelial dysfunction. Some of these adverse events were associated with the presence of durable polymers, which were essential to allow the elution of the immunosuppressive drug in the first DES designs. The introduction of erodable polymers in DES technology has provided the potential to complete the degradation of the polymer simultaneously or immediately after the release of the immunosuppressive drug, after which a BMS remains in place.Several DES designs with biodegradable (BIO) polymers have been introduced in preclinical and clinical studies, including randomized trials. In this review, we analyze the clinical results from 6 observational and randomized studies with BIO polymers and discuss advantages and disadvantages of this new technology.

Efficacy and safety of a biodegradable polymer Cobalt‐Chromium sirolimus‐eluting stent (EXCEL2) in treating de novo coronary artery disease: A pooled analysis of the CREDIT II and CREDIT III trials

“…Drug‐eluting stents (DES) effectively prevent intimal re‐proliferation after stent implantation compared with bare metal stents; therefore, they significantly reduce restenosis and associated adverse cardiovascular events such as cardiac death and myocardial infarction . However, DES with durable polymer (DP‐DES) was proven to be responsible for persistent vascular wall inflammation and markedly delayed endothelialization; this led to an increased risk of late or very late stent thrombosis , and consequently, a prolonged duration of double anti‐platelet therapy . Biodegradable polymer DES (BP‐DES) is characterized by a coating that completely degrades within 6–9 months and was recently reported to strongly attenuate the risk of late stent thrombosis compared to DP‐DES in several clinical trials .…”

Stent Thrombosis in Patients With Coronary Artery Disease Treated With Biodegradable Polymer Drug-Eluting Stents

“…4) Durable polymer-induced chronic infl ammation has been identifi ed as a possible contributor to late or very late ST, especially because late and very late ST occurred long after antiproliferative drugs have been eluted from the polymer. Biodegradable polymers, which are composed of PLA or PLGA, can be metabolized in the body (breaking down into monomers, water and carbon dioxide), reduce the infl ammatory response, and decrease the risk of late complications such as stent uncovering, mal-apposition, and endothelial dysfunction, 23) so biodegradable polymer stents are associated with more complete strut coverage. 24) Furthermore, biolimus, which is used as the antiproliferative agent in most biodegradable polymer stents, is a highly lipophilic, semisynthetic sirolimus analogue, and has been shown to reduce insegment 11,14,15) and in-stent late loss, 11,14,15) and subsequent revascularization.…”

Influence of fibre diameter and orientation of electrospun copolyetheresterurethanes on smooth muscle and endothelial cell behaviour

“…Additionally, DES are associated with increased platelet activation and aggregation compared to bare metal stents (BMS) [20]. Synergistically, these effects can promote adverse events like LST limiting the long term performance of DES.…”