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stent AND Fe

Ziyang Jin, Xufeng Yan, Guiyong Liu, Min Lai
Cardiovascular disease has become a great threat to the health of mankind; current titanium (Ti) stents fail due to late stent thrombosis caused by the lack of re-endothelialization of the Ti stent. The objective of this study was to design a novel cardiovascular Ti implant with improved surface biocompatibility. TiO2 nanotubes with a diameter of 110 nm were anodized at a constant voltage of 30 V, and fibronectin was immobilized onto the TiO2 nanotubes using polydopamine. The element composition, morphology, and wettability of the different substrate surfaces were characterized by x-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and contact angle measurements, respectively, confirming the successful immobilization of fibronectin...
January 1, 2018: Journal of Biomaterials Applications
Ehsan Mostaed, Malgorzata Sikora-Jasinska, Jaroslaw W Drelich, Maurizio Vedani
The search for biodegradable metals with mechanical properties equal or higher to those of currently used permanent biomaterials, such as stainless steels, cobalt chromium and titanium alloys, desirable in vivo degradation rate and uniform corrosion is still an open challenge. Magnesium (Mg), iron (Fe) and zinc (Zn)-based alloys have been proposed as biodegradable metals for medical applications. Over the last two decades, extensive research has been done on Mg and Fe. Fe-based alloys show appropriate mechanical properties, but their degradation rate is an order of magnitude below the benchmark value...
April 15, 2018: Acta Biomaterialia
Giorgia M Bosi, Claudio Capelli, Mun Hong Cheang, Nicola Delahunty, Michael Mullen, Andrew M Taylor, Silvia Schievano
Patient-specific computational models are an established tool to support device development and test under clinically relevant boundary conditions. Potentially, such models could be used to aid the clinical decision-making process for percutaneous valve selection; however, their adoption in clinical practice is still limited to individual cases. To be fully informative, they should include patient-specific data on both anatomy and mechanics of the implantation site. In this work, fourteen patient-specific computational models for transcatheter aortic valve replacement (TAVR) with balloon-expandable Sapien XT devices were retrospectively developed to tune the material parameters of the implantation site mechanical model for the average TAVR population...
April 11, 2018: Journal of Biomechanics
Brandon J Tefft, Susheil Uthamaraj, Adriana Harbuzariu, J Jonathan Harburn, Tyra A Witt, Brant Newman, Peter J Psaltis, Ota Hlinomaz, David R Holmes, Rajiv Gulati, Robert D Simari, Dan Dragomir-Daescu, Gurpreet S Sandhu
Incomplete endothelialization of intracoronary stents has been associated with stent thrombosis and recurrent symptoms, whereas prolonged use of dual antiplatelet therapy increases bleeding-related adverse events. Facilitated endothelialization has the potential to improve clinical outcomes in patients who are unable to tolerate dual antiplatelet therapy. The objective of this study was to demonstrate the feasibility of magnetic cell capture to rapidly endothelialize intracoronary stents in a large animal model...
March 13, 2018: Tissue Engineering. Part A
C Ganesh Pai, M Ganesh Kamath, Mamatha V Shetty, Annamma Kurien
AIM: To assess the outcomes of drug therapy (DT) followed by pancreatic endotherapy for continuing painful episodes in recurrent acute pancreatitis. METHODS: DT comprised of pancreatic enzymes and anti-oxidants failing which, endotherapy (ET; pancreatic sphincterotomy and stent placement) was done. The frequency of pain, its visual analogue score (VAS), quality of life (QoL), serum C peptide and faecal elastase were compared between baseline and after 1 year of follow up in all patients and in the two subgroups on DT and ET...
May 21, 2017: World Journal of Gastroenterology: WJG
Qiang Wang, Yibin Ren, M Babar Shahzad, Wei Zhang, Xumeng Pan, Song Zhang, Dan Zhang
Co-Cr-W-Ni alloy (L605) with high tensile strength is used in coronary stents. The thickness of individual strut of the stent is reduced which can decrease the stent restenosis rate. However, about 10% Ni element content in L605 is found to cause allergic reactions and pulmonary embolism, similar to the traditional 316L stainless steel. In this study, a novel nickel-free cobalt-base alloy Co-20Cr-12Fe-18Mn-2Mo-4W-N (wt%) was designed and fabricated in order to efficiently avoid the potential hazards of Ni element...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
E Galvin, D O'Brien, C Cummins, B J Mac Donald, C Lally
This paper presents a strain-mediated phenomenological corrosion model, based on the discrete finite element modelling method which was developed for use with the ANSYS Implicit finite element code. The corrosion model was calibrated from experimental data and used to simulate the corrosion performance of a WE43 magnesium alloy stent. The model was found to be capable of predicting the experimentally observed plastic strain-mediated mass loss profile. The non-linear plastic strain model, extrapolated from the experimental data, was also found to adequately capture the corrosion-induced reduction in the radial stiffness of the stent over time...
June 2017: Acta Biomaterialia
Wenjiao Lin, Li Qin, Haiping Qi, Deyuan Zhang, Gui Zhang, Runlin Gao, Hong Qiu, Ying Xia, Ping Cao, Xiang Wang, Wei Zheng
Pure iron as a potential bioresorbable material for bioresorbable coronary scaffold has major disadvantages of slow corrosion and bioresorption. However, so far, there are neither quantitative data of long-term in vivo corrosion nor direct experimental evidence for bioresorption of pure iron and its alloys, which are fundamental and vital for developing novel Fe-based alloys overcoming the intrinsic drawbacks of pure iron. This work systemically investigated scaffold performance, long-term in vivo corrosion behavior and biocompatibility of a nitrided iron coronary scaffold and explored its bioresorption mechanism...
May 2017: Acta Biomaterialia
Arezoo Khosravi, Hossein Bahreinizad, Milad Salimi Bani, Alireza Karimi
Undesirable deformation of the stent can induce a significant amount of injure not only to the blood vessel but also to the plaque. The objective of this study was to reduce/minimize these undesirable deformations by the application of Functionally Graded Materials (FGM). To do this, Finite Element (FE) method was employed to simulate the expansion of a stent and the corresponding displacement of the stenosis plaque. Three hyperelastic plaque types as well as five elastoplastic stents were simulated. Dogboning, foreshortening, maximum stress in the plaque, and the pressure which is needed to fully expand the stent for different stent materials, were acquired...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Can Gökgöl, Nicolas Diehm, Philippe Büchler
Oversizing of the Nitinol stents in the femoro-popliteal arterial tract is commonly performed by clinicians and further encouraged by stent manufacturers. However, in spite of the procedure's supposed benefits of strong wall apposition and increased luminal gain, its effects on the mechanical behavior of arteries with peripheral arterial disease are not fully clear. In this study, finite element (FE) analyses of endovascular revascularization of an idealized artery with 70% stenosis and three different plaque types have been performed to examine the influence of Nitinol stent oversizing on the arterial stresses and acute lumen gain...
June 2017: Annals of Biomedical Engineering
Mónica Echeverry-Rendon, Lisa M Reece, Fernando Pastrana, Sandra L Arias, Akshath R Shetty, Juan Jose Pavón, Jean Paul Allain
Current treatments for brain aneurysms are invasive, traumatic, and not suitable in most patients with increased risks. A new alternative method is using scaffold stents to create a local and focal attraction force of cells for an in situ reconstruction of the tunica media. For this purpose, a nanostructured bioactive coating is designed to render an asymmetric region of the stent scaffold magnetic and biomimetic, which utilizes bacterial nanocellulose (BNC) as a platform for both magnetic and cell attraction as well as proliferation...
January 24, 2017: Macromolecular Bioscience
Chunling Qin, Qingfeng Hu, Yongyan Li, Zhifeng Wang, Weimin Zhao, Dmitri V Louzguine-Luzgin, Akihisa Inoue
We demonstrate, for the first time, that the (Fe0.75B0.15Si0.1)100-xNbx (x=0, 1 and 3at.%) metallic glasses without toxic and allergic elements exhibit excellent apatite-forming ability in simulated body fluids (SBF), which is expected to be a new generation of biomaterials in stents and orthopedic implants. For the alloys without any surface treatment, spherical particles corresponding to octacalcium phosphate are spontaneously nucleated and precipitated throughout the alloy surface after immersion only for 1day, indicating that the present alloys possess an unusual high bioactivity...
December 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
E Mostaed, M Sikora-Jasinska, A Mostaed, S Loffredo, A G Demir, B Previtali, D Mantovani, R Beanland, M Vedani
The search for a degradable metal simultaneously showing mechanical properties equal or higher to that of stainless steel and uniform degradation is still an open challenge. Several magnesium-based alloys have been studied, but their degradation rate has proved to be too fast and rarely homogeneous. Fe-based alloys show appropriate mechanical properties but very low degradation rate. In the present work, four novel Zn-Mg and two Zn-Al binary alloys were investigated as potential biodegradable materials for stent applications...
July 2016: Journal of the Mechanical Behavior of Biomedical Materials
Ali I Alherz, Omar Tanweer, Vittoria Flamini
Dual-layer stents and multi-layer stents represent a new paradigm in endovascular interventions. Multi-layer stents match different stent designs in order to offer auxiliary functions. For example, dual-layer stents used in the endovascular treatment of intracranial aneurysms, like the FRED(TM) (MicroVention, CA) stent, combine a densely braided inner metallic mesh with a loosely braided outer mesh. The inner layer is designed to divert blood flow, whereas the outer one ensures microvessels branching out of the main artery remain patent...
August 16, 2016: Journal of Biomechanics
Essowè Mouzou, Carlo Paternoster, Ranna Tolouei, Agung Purnama, Pascale Chevallier, Dominique Dubé, Frédéric Prima, Diego Mantovani
High manganese austenitic steels such as Fe-20Mn-1.2C alloys are among the most promising candidates for biodegradable stents applications due to their high strength, high ductility and their chemical composition. In the current work, 14 day static in-vitro tests were performed in controlled atmosphere to assess the degradation behavior in three common pseudo-physiological solutions, i.e. commercial Hanks' (CH), modified Hanks' (MH) and albumin-enriched Dulbecco's modified phosphate buffered saline (DPBS) solutions...
April 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Francesco Iannaccone, Matthieu De Beule, Sander De Bock, Imramsjah M J Van der Bom, Matthew J Gounis, Ajay K Wakhloo, Matthieu Boone, Benedict Verhegghe, Patrick Segers
Clinical studies have demonstrated the efficacy of stent supported coiling for intra-cranial aneurysm treatment. Despite encouraging outcomes, some matters are yet to be addressed. In particular closed stent designs are influenced by the delivery technique and may suffer from under-expansion, with the typical effect of "hugging" the inner curvature of the vessel which seems related to adverse events. In this study we propose a novel finite element (FE) environment to study potential failure able to reproduce the microcatheter "pull-back" delivery technique...
February 2016: Annals of Biomedical Engineering
Jennifer Frattolin, Rajib Barua, Huseyin Aydin, Sriraman Rajagopalan, Luca Gottellini, Richard Leask, Stephen Yue, David Frost, Olivier F Bertrand, Rosaire Mongrain
The implementation of biodegradable stents has the potential to revolutionize obstructive coronary artery disease treatment. Limitations still currently exist, however, that prevent biodegradable stents from replacing permanent metallic stents in the global market. The ideal combination of stent properties, including sufficient mechanical strength, controlled degradation, and biocompatibility, has yet to be realized. A novel manufacturing process is proposed that utilizes cold gas-dynamic spraying to fabricate a metal structure with significantly reduced grain size...
February 2016: Annals of Biomedical Engineering
Daria Cosentino, Claudio Capelli, Graham Derrick, Sachin Khambadkone, Vivek Muthurangu, Andrew M Taylor, Silvia Schievano
AIMS: We report the application of patient-specific computational models to plan the treatment of complex aortic re-coarctation (rCoA) with a proximal aberrant right subclavian artery in a patient who had previously undergone bare metal stenting. METHODS AND RESULTS: Clinically acquired images were used to set up patient-specific computational models for finite element (FE) and fluid dynamics (CFD) analyses. The 3D geometry was reconstructed from computed tomography and echocardiography images...
October 2015: EuroIntervention
Sufia Islam, Stefan Jarosch, Juan Zhou, Maria del Carmen Parquet, James Thomas Toguri, Patricia Colp, Bruce E Holbein, Christian Lehmann
BACKGROUND: Sepsis is the systemic inflammatory response to an infection. Generation of reactive oxygen species represents an important part of the inflammatory cascade in sepsis. Dysregulation of iron homeostasis can further promote the generation of radicals and amplify the damage caused by systemic immune activation. This can potentially be suppressed or prevented by iron chelation. Therefore, this study was designed to examine the effects of a novel iron chelator (DIBI) with or without standard antibiotic treatment in colon ascendens stent peritonitis (CASP)-induced experimental sepsis...
January 2016: Journal of Surgical Research
Jan-Marten Seitz, Martin Durisin, Jeremy Goldman, Jaroslaw W Drelich
Sutures that biodegrade and dissolve over a period of several weeks are in great demand to stitch wounds and surgical incisions. These new materials are receiving increased acceptance across surgical procedures whenever permanent sutures and long-term care are not needed. Unfortunately, both inflammatory responses and adverse local tissue reactions in the close-to-stitching environment are often reported for biodegradable polymeric sutures currently used by the medical community. While bioabsorbable metals are predominantly investigated and tested for vascular stent or osteosynthesis applications, they also appear to possess adequate bio-compatibility, mechanical properties, and corrosion stability to replace biodegradable polymeric sutures...
September 16, 2015: Advanced Healthcare Materials
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