Coating defects in polymer-coated drug-eluting stents

Abstract

Vascular stenting has a great attention as a treatment for coronary arteries diseases as compared with percutaneous balloon angioplasty. In-stent restenosis and thrombosis are side effects resulting from using bare metal stent (BMS). Employing platelet therapy allowed to reduce the rate of thrombosis, however, the rate of restenosis remains a major problem. In 2002, drug-eluting stents (DESs) were introduced as an effort to reduce the restenosis. The commercially available DESs continue to suffer from coating defects that might lead to a series of adverse effects. Most importantly, multiple concerns remain regarding the polymer coating integrity on metal surfaces or the relation of polymer irregularities to longterm adverse events.

Surface Modification of Biodegradable Polymers towards Better Biocompatibility and Lower Thrombogenicity

“…The introduction of drug eluting stents (DES), which allow the delivery of drugs in a controlled manner to the arterial wall significantly reduced the rate of restenosis, occurring after bare metal stent (BMS) implantation [ 7 , 8 ]. Restenosis caused by neointimal hyperplasia is a side-effect of the normal healing process, mainly resulting from uncontrolled proliferation and migration of arterial smooth muscle cells, as well as excessive expression and deposition of extracellular matrix (ECM) [ 9 , 10 ].…”

Self-protonating, plasma polymerized, superimposed multi-layered biomolecule nanoreservoir as blood-contacting surfaces

“…To achieve effective shielding, robustness of both coating itself and its conjugated biomolecules are of equal importance. Overall smoothness can greatly reduce friction and wear of surface molecules, which is especially crucial in blood-contacting devices, where drug-eluting coatings often lose their anti-coagulant molecules too quickly and cause thrombosis due to the surface roughness of coating [19]. This also potentially explains the excellent retention of biomolecules even under dynamic flow conditions in our system due to the lowered frictional drag in proximity of coating [20].…”

The role of invasive and non-invasive imaging technologies and calcium modification therapies in the evaluation and management of coronary artery calcifications

“…Electronic microscopy has shown that this can lead to phenomena of cracking, ridging, webbing, and peeling-off of the polymer. Damage of stent platform and polymer can interfere with the kinetics of drug elution and potentially cause long-term stent failure ( 6 , 7 ).…”