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Acute scaffold disruption and late discontinuities
Published in Yoshinobu Onuma, Patrick W.J.C. Serruys, Bioresorbable Scaffolds, 2017
Yoshinobu Onuma, Yohei Sotomi, Takeshi Kimura, Robert-Jan M. van Geuns, Patrick W.J.C. Serruys
The current BRSs are composed of either a polymer or bioresorbable metal alloy. The key mechanical traits for candidate material in coronary indications include high elastic moduli to impart radial stiffness, large break strains to impart the ability to withstand deformations from the crimped to expanded states, and low yield strains to reduce the amount of recoil and overinflation necessary to achieve a target deployment. Primarily due to the mechanical properties of the selected materials, however, the functionality of the bioresorbable scaffold is somewhat limited (Table 8.5.1).
Drug-eluting bioresorbable scaffolds in cardiovascular disease, peripheral artery and gastrointestinal fields: a clinical update
Published in Expert Opinion on Drug Delivery, 2020
Hideyuki Kawashima, Masafumi Ono, Norihiro Kogame, Kuniaki Takahashi, Chun-Chin Chang, Hironori Hara, Chao Gao, Rutao Wang, Mariusz Tomaniak, Rodrigo Modolo, Joanna J. Wykrzykowska, Robbert J. De Winter, Faisal Sharif, Patrick W. Serruys, Yoshinobu Onuma
Bioresorbable scaffold (BRS) was designed to provide temporary scaffolding and disappear in the later phase with biodegradation of the device. Early serial angiographic follow-up after balloon angioplasty demonstrated that the constrictive remodeling or neointimal hyperplasia is a time-limited phenomenon after constructive balloon angioplasty. The peak of the vascular constriction occurs approximately 3 to 6 months after PCI. Beyond that timepoint, the scaffolding capacity of the device is no longer necessary. Therefore, BRS theoretically could restore the natural physiological function of coronary artery without compromising the early efficacy in preventing the constrictive remodeling as well as neointimal hyperplasia. The first BRS was implanted in 1999. This initial IGAKI-TAMAI scaffold was without drug elution, resulting in acceptable but significant restenosis rate similar to BMS.
Drug-eluting stents for the treatment of coronary artery disease: A review of recent advances
Published in Expert Opinion on Drug Delivery, 2022
The DES, composed of a metallic platform, specific drug, and polymers or coating for drug release, markedly reduced restenosis. However, the need for further advances still exists to improve patient survival or clinical outcomes. A metallic platform requires thinner struts but without compromising the radial strength with adequate radiopacity. A balanced stent design with trackability or crossability but without a reduction of longitudinal strength is essential. Bifurcation lesions are still complex and associated with higher rates of periprocedural complications, in-stent restenosis, and stent thrombosis. Therefore, dedicated bifurcation stents require to overcome a limitation of procedural complexity and the limited choice and sizes of device available. Besides the metallic platform, bioresorbable coronary scaffolds are developed to provide transient mechanical vessel support against acute recoil and drug delivery followed by complete resorption with an expectation of the potential benefits of a reduction in long-term adverse events from permanent materials, restoration of the arterial physiology of the treated vessel through bioresorption, and maintenance of suitability for future possible treatment options of either percutaneous or surgical revascularization. However, technological refinement and progress in manufacturing to improve mechanical integrity are still needed because of current issues identified by histopathologic evaluation of bioresorbable scaffold in preclinical and clinical studies; mild increases in inflammation during bioresorption, greater acute thrombogenicity, delayed endothelialization of thicker struts, and a higher risk of device thrombosis and other clinical events than DES.
Magmaris resorbable magnesium scaffold for the treatment of coronary heart disease: overview of its safety and efficacy
Published in Expert Review of Medical Devices, 2019
Johan Bennett, Quentin De Hemptinne, Keir McCutcheon
Despite the compelling evidence of metallic DES efficacy in a large proportion of patients, important limitations remain such as hypersensitivity reactions, late stent thrombosis, and neoatherosclerotic stent failure. Bioresorbable scaffold technology was therefore introduced to overcome some of these limitations by enabling transient mechanical vessel support before complete resorption of the scaffold. The AMS, DREAMS-1G, and DREAMS-2G (Magmaris) represent an iterative progression of absorbable metal scaffolds, with each successive generation implementing changes to improve device performance, efficacy, and safety. Results of Magmaris RMS in the treatment of simple coronary artery disease demonstrate favorable clinical efficacy and safety outcome data with respect to low target lesion failures and ischemia-driven TLR rates with just one published case of scaffold thrombosis to date in the BIOSOLVE studies. Further improvements in the magnesium scaffold device characteristics in the next generation DREAMS 3-G will potentially lead to further advancements in performance in terms of safety and efficacy. Within 5 years, the next generation magnesium scaffold DREAMS 3-G will have likely obtained CE marking and will be under evaluation in large-scale clinical trials including randomized studies where its efficacy will be compared against metallic DES. It is also probable that during the next 5 years more fourth-generation devices with ever-increasing biocompatibility and safety profiles will be investigated and released commercially. Although biodegradable devices will not replace the conventional metallic DES in the foreseeable future, in the next 5 to 10 years they will start to play a much more prominent role, especially in the treatment of simple coronary artery disease in younger patients. Whether there will be a place for this technology in complex coronary interventions remains to be seen.