Bioerodable stents

Coronary stents have revolutionized the treatment of coronary artery disease. Improvement in clinical outcomes requires detailed evaluation of the performance of stent biomechanics and the effectiveness as well as safety of biomaterials aiming at optimization of endovascular devices. Stents need to harmonize the hemodynamic environment and promote beneficial vessel healing processes with decreased thrombogenicity. Stent design variables and expansion properties are critical for vessel scaffolding. Drug-elution from stents, can help inhibit in-stent restenosis, but adds further complexity as drug release kinetics and coating formulations can dominate tissue responses...

Nitric oxide (NO) occurs naturally in mammalian biochemistry as a critical signaling molecule and exhibits antithrombotic, antibacterial, and wound-healing properties. NO-forming biodegradable polymers have been utilized in the development of antithrombotic or antibacterial materials for biointerfacial applications, including tissue engineering and the fabrication of erodible coatings for medical devices such as stents. Use of such NO-forming polymers has frequently been constrained by short-term release or limited NO storage capacity and has led to the pursuit of new materials with improved NO release function...

This paper reviews the latest research and development of drug-eluting stents. The emphasis is on coronary stenting, and both biostable and bioerodible stents are covered in this review. The advantages and shortcomings of the bioactive molecules used in these stents are analyzed, along with the rationale for using bioerodible coatings. The overall emphasis is on the performance of these stents in the clinic. Based on the evaluation of the different stent types, we conclude that fully-erodible stents with a coating of antiproliferative drug will slowly gain market share in the near future, and that the search for a more selective anti-proliferative compound will continue...

OBJECTIVES: The present study was designed to evaluate a novel bioerodible sol-gel film coated paclitaxel-eluting stent (sol-gel-PES, 3 microg per stent) in a porcine coronary artery model. BACKGROUND: Although current polymer-based PES decrease restenosis, the permanent polymer and bound drug have raised concerns regarding delayed vessel healing and late stent thrombosis. METHODS: Polymer-based PES (poly-PES, n = 8), sol-gel-PES (n = 15), bare metal (BMS, n = 14), and sol-gel film only (sham, n = 12), stents were implanted in 17 juvenile pigs...

PURPOSE: To evaluate effect of controlled stent-based release of an NO donor to limit in-stent restenosis in rabbits. MATERIALS AND METHODS: Bioerodable microspheres containing NO donor or biodegradable polymer (polylactide-co-glycolide-polyethylene glycol) were prepared and loaded in channeled stents. Daily concentrations of NO release from NO-containing microspheres were assayed in vitro. NO- and polymer-containing (control) microsphere-loaded stents were deployed in aortas of New Zealand white rabbits (n = 8)...

The objective of this work was to develop a platform to evaluate and deliver putative therapeutic agents for in-stent restenosis. Arterial stenting is applied in more than 60% of balloon angioplasties for treating cardiovascular disease. However, stented arteries encounter accelerated rates of restenosis. No prior platform has allowed evaluation or local management of in-stent restenosis without perturbing the very system being examined. A stainless steel, balloon-expandable stent was modified to serve as an ablumenal drug delivery platform...

OBJECTIVES: The purpose of this study was to determine long-term effects of stent-based paclitaxel delivery on amount, rate and composition of neointimal thickening after stent implantation. BACKGROUND: Paclitaxel prevents vascular smooth muscle cell proliferation and migration in vitro and in vivo. These actions, coupled with low solubility, make it a viable candidate for modulating vascular responses to injury and prolonged effects after local delivery. We asked whether local delivery of paclitaxel for a period of weeks from a stent coated with a bioerodible polymer could produce a sustained reduction in neointimal hyperplasia for up to six months after stenting...