Journal articles: 'Stent coating'

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Antonowicz, Magdalena, Janusz Szewczenko, Joanna Jaworska, Katarzyna Jelonek, Kamil Joszko, Bożena Gzik-Zroska, Paweł M. Nuckowski, et al. "Functional Properties of Polyurethane Ureteral Stents with PLGA and Papaverine Hydrochloride Coating." International Journal of Molecular Sciences 22, no. 14 (July 19, 2021): 7705. http://dx.doi.org/10.3390/ijms22147705.

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Despite the obvious benefits of using ureteral stents to drain the ureters, there is also a risk of complications from 80–90%. The presence of a foreign body in the human body causes disturbances in its proper functioning. It can lead to biofilm formation on the stent surface, which may favor the development of urinary tract infections or the formation of encrustation, as well as stent fragmentation, complicating its subsequent removal. In this work, the effect of the polymeric coating containing the active substance-papaverine hydrochloride on the functional properties of ureteral stents significant for clinical practice were assessed. Methods: The most commonly clinically used polyurethane ureteral Double-J stent was selected for the study. Using the dip-coating method, the surface of the stent was coated with a poly(D,L-lactide-glycolide) (PLGA) coating containing the papaverine hydrochloride (PAP). In particular, strength properties, retention strength of the stent ends, dynamic frictional force, and the fluoroscopic visibility of the stent during X-ray imaging were determined. Results: The analysis of the test results indicates the usefulness of a biodegradable polymer coating containing the active substance for the modification of the surface of polyurethane ureteral stents. The stents coated with PLGA+PAP coating compared to polyurethane stents are characterized by more favorable strength properties, the smaller value of the dynamic frictional force, without reducing the fluoroscopic visibility.

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Rebelo, Rita, Jorge Padrão, Margarida M. Fernandes, Sandra Carvalho, Mariana Henriques, Andrea Zille, and Raul Fangueiro. "Aging Effect on Functionalized Silver-Based Nanocoating Braided Coronary Stents." Coatings 10, no. 12 (December 16, 2020): 1234. http://dx.doi.org/10.3390/coatings10121234.

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A previously developed fiber-based polyester (PES) stent, with mechanical properties comparable to commercial nitinol stents, was coated with metallic silver (Ag0) and silver oxides (AgxO) thin films through direct current (DC) magnetron sputtering. Ag0 and AgxO coatings provide antimicrobial properties to the stents to minimize the occurrence of coronary stent infections. Nevertheless, the stent interacts with the atmosphere and then with the biological fluids and may lead to the generation of silver species with diminished antimicrobial efficiency and/or prone to induce cytotoxicity. Therefore, stent coating nanostructures aged 3 months were thoroughly analyzed by X-ray photoelectron spectroscopy (XPS) and their antimicrobial and cytotoxicity properties were assessed. Aging led to the presence of silver carbonate and bicarbonate as well as chemisorbed oxygen species in Ag0 and AgxO coatings. Bactericidal efficacy was tested against an important nosocomial bacterium, particularly associated to indwelling devices: Staphylococcus epidermidis. Aged Ag0 and AgxO coating presented a Log reduction of 1 and 2 at their surface; respectively. However, aged stents were able to induce a Log reduction of 2 (Ag0) and 4 (AgxO) on the surrounding medium. Only aged AgxO stent was able to provide a mild reduction of the bacterium at its surface and a clear antimicrobial effect (Log reduction >3) within its vicinity. More importantly, both aged Ag0 and AgxO stents were shown to be compatible with fibroblasts cells indicating that they can be safely used as indwelling devices, despite the aging effect.

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Xu, Xiangshan, Lijie Wang, Guofeng Wang, and Yuanzhe Jin. "The effect of REDV/TiO2 coating coronary stents on in-stent restenosis and re-endothelialization." Journal of Biomaterials Applications 31, no. 6 (November 10, 2016): 911–22. http://dx.doi.org/10.1177/0885328216675829.

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The coronary artery stent has been widely used in clinic. In-stent restenosis was mainly caused by the excessive proliferation of smooth muscle cell and the inflammation due to the metal ion released from stent scaffold of the drug-eluting stent. Thus, to reduce the in-stent restenosis and promote the vascular endothelialization have become a hot research point in this area. In this paper, a nano-TiO2 ceramic coating was deposited on 316L stainless steel to reduce the metal ion release and to inhibit the inflammation reaction. An endothelia cell selective adhesion peptide Arg-Glu-Asp-Val (REDV) coating was prepared on the ceramic coating by a polydopamine technology to promote the endothelialization. The corrosion test indicated that nano-TiO2 ceramic film could effectively decrease the nickel ion released from 316L stainless steel. REDV/TiO2 coating could promote the endothelial cell adhesion and proliferation, meanwhile REDV/TiO2 coating could also increase the nitric oxide concentration. Bare metal stent, TiO2-coated stent and REDV/TiO2-coated stent were implanted in the iliac arteries of rabbit model. In-stent restenosis and re-endothelialization were evaluated at 28 days post-implantation of the stents. The results showed that REDV/TiO2-coated stents could effectively reduce in-stent restenosis and promote re-endothelialization in comparison with TiO2-coated drug-eluting stent and bare metal stent. These results suggest that REDV/TiO2-coated drug-eluting stent maybe a good choice of the application for coronary artery disease.

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Curcio, Antonio, Daniele Torella, Giovanni Cuda, Carmela Coppola, Maria Concetta Faniello, Francesco Achille, Viviana G. Russo, Massimo Chiariello, and Ciro Indolfi. "Effect of stent coating alone on in vitro vascular smooth muscle cell proliferation and apoptosis." American Journal of Physiology-Heart and Circulatory Physiology 286, no. 3 (March 2004): H902—H908. http://dx.doi.org/10.1152/ajpheart.00130.2003.

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Synthetic polymers, like methacrylate (MA) compounds, have been clinically introduced as inert coatings to locally deliver drugs that inhibit restenosis after stent. The aim of the present study was to evaluate the effects of MA coating alone on vascular smooth muscle cell (VSMC) growth in vitro. Stainless steel stents were coated with MA at the following doses: 0.3, 1.5, and 3 ml. Uncoated/bare metal stents were used as controls. VSMCs were cultured in dishes, and a MA-coated stent or an uncoated bare metal stent was gently added to each well. VSMC proliferation was assessed by bromodeoxyuridine (BrdU) incorporation. Apoptosis was analyzed by three distinct approaches: 1) annexin V/propidium iodide fluorescence detection; 2) DNA laddering; and 3) caspase-3 activation and PARP cleavage. MA-coated stents induced a significant decrease of BrdU incorporation compared with uncoated stents at both the low and high concentrations. In VSMCs incubated with MA-coated stents, annexin V/propidium iodide fluorescence detection showed a significant increase in apoptotic cells, which was corroborated by the typical DNA laddering. Apoptosis of VSMCs after incubation with MA-coated stents was characterized by caspase-3 activation and PARP cleavage. The MA-coated stent induced VSMC growth arrest by inducing apoptosis in a dose-dependent manner. Thus MA is not an inert platform for eluting drugs because it is biologically active per se. This effect should be taken in account when evaluating an association of this coating with antiproliferative agents for in-stent restenosis prevention.

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Robák, Beáta, Péter Szabadíts, Eszter Bognár, Zsolt Puskás, and Andrea Toldy. "Analysis of the Polymer Coatings of Coronary Stents from the Aspect of Drug Absorbing and Eluting." Materials Science Forum 659 (September 2010): 245–50. http://dx.doi.org/10.4028/www.scientific.net/msf.659.245.

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The rate of restenosis can be decreased by the usage of drug eluting stents compared to bare metal stents. The aim of this work was the optimization of micro sprayed polymer coatings for medical applications and the examination of drug absorbing and releasing properties of these coatings. Control groups were bare metal stent models (316 LVM type austenitic stainless steel tube slices). Different types of medical grade polyurethane granules were applied onto the stent surface. Various methods were used for the examination of the surface and coating quality, such as optical microscopy, scanning electron microscopy and atomic force microscopy.

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Bognár, Eszter, György Ring, Hilda Zsanett Marton, János Dobránszky, and János Ginsztler. "Polyurethane Coating on Coronary Stents." Key Engineering Materials 345-346 (August 2007): 1269–72. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1269.

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Stents are special metallic or polymer endoprostheses of meshed structure and tube shape. Their function is to prevent restenosis in the arteries. Stents can be coated or uncoated. In the expanded part of the artery the chance of restenosis is bigger even without a stent so it is practical to coat the stents. The aim of this work is to present the results of the coating experiments made on the coronary stents. Three types of commercially available polyurethanes were used for these experiments. The coatings were produced by a dipping method. Electro-polished and non-electro-polished metallic sheets and stents were used for these experiments. Contact angle measurements were done to examine the wetting properties of the three different polyurethane coatings. The quality and the changing of the coatings were examined by different methods (stereomicroscope, scanning electron microscope and energy dispersive spectrometry).

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Gallino, Enrico, Michael Tatoulian, Farzaneh Arefi-Khonsari, and D. Mantovani. "Plasma Surface Modification of 316L Stainless Steel for Cardiovascular Stent Coating." Advanced Materials Research 89-91 (January 2010): 196–201. http://dx.doi.org/10.4028/www.scientific.net/amr.89-91.196.

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Coronary stents are metallic (316L stainless steel) devices employed during balloon angioplasty to reopen and prevent the re-obstruction of a diseased narrowed area within a coronary artery. To reduce restenosis rate, bare metal stent coating is a promising solution. The coating can act as an anticorrosive barrier against the aggressive properties of biological environment, improving the long-term safety of the device. The goal of this study is to develop a dry process to isolate metallic surface from the biological environment by depositing a thin plasma polymerized allylamine (CH2=CH-CH2-NH2) film on the metallic surface. Plasma polymerized allylamine films were deposited on flat electropolished 316L stainless steel samples in a low pressure plasma reactor (70 kHz). Chemical composition of the coatings has been analysed as a function of the discharge power and treatment time. Moreover, special attention has been paid on the stability of the coating after immersion during 24 hours in D.I. water. Finally, to mimic stent expansion conditions, a “small punch test” has been used to investigate the adhesive properties of the coating. Our results demonstrate that is possible to deposit a stable, cohesive and adhesive plasma polymerized allylamine thin film which can be used as a coating for cardiovascular stents

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Diaz-Rodriguez, Sergio, Charlotte Rasser, Jules Mesnier, Pascale Chevallier, Romain Gallet, Christine Choqueux, Guillaume Even, et al. "Coronary stent CD31-mimetic coating favours endothelialization and reduces local inflammation and neointimal development in vivo." European Heart Journal 42, no. 18 (February 13, 2021): 1760–69. http://dx.doi.org/10.1093/eurheartj/ehab027.

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Abstract Aims The rapid endothelialization of bare metal stents (BMS) is counterbalanced by inflammation-induced neointimal growth. Drug-eluting stents (DES) prevent leukocyte activation but impair endothelialization, delaying effective device integration into arterial walls. Previously, we have shown that engaging the vascular CD31 co-receptor is crucial for endothelial and leukocyte homeostasis and arterial healing. Furthermore, we have shown that a soluble synthetic peptide (known as P8RI) acts like a CD31 agonist. The aim of this study was to evaluate the effect of CD31-mimetic metal stent coating on the in vitro adherence of endothelial cells (ECs) and blood elements and the in vivo strut coverage and neointimal growth. Methods and results We produced Cobalt Chromium discs and stents coated with a CD31-mimetic peptide through two procedures, plasma amination or dip-coating, both yielding comparable results. We found that CD31-mimetic discs significantly reduced the extent of primary human coronary artery EC and blood platelet/leukocyte activation in vitro. In vivo, CD31-mimetic stent properties were compared with those of DES and BMS by coronarography and microscopy at 7 and 28 days post-implantation in pig coronary arteries (n = 9 stents/group/timepoint). Seven days post-implantation, only CD31-mimetic struts were fully endothelialized with no activated platelets/leukocytes. At day 28, neointima development over CD31-mimetic stents was significantly reduced compared to BMS, appearing as a normal arterial media with the absence of thrombosis contrary to DES. Conclusion CD31-mimetic coating favours vascular homeostasis and arterial wall healing, preventing in-stent stenosis and thrombosis. Hence, such coatings seem to improve the metal stent biocompatibility.

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Hernandez Marulanda, Andres Felipe, Jairo Alonso Perez Arrieta, Lina Marcela Hoyos Palacios, and Raul Adolfo Valencia. "Fluid-structure study of a polymeric coating reinforced with carbon nanotubes (CNT) for potential application in stents." DYNA 86, no. 211 (October 1, 2019): 300–307. http://dx.doi.org/10.15446/dyna.v86n211.80730.

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The therapeutic approach of the atherosclerotic plaque has been visualized from multiple perspectives, which include from the handling of drugs until the implantation of medical devices like stents. A current alternative to restenosis appearance, is the use of stents with drugreleasing coatings. The present work seeks to analyze the structural and hemodynamic behavior and to understand the effects between the interaction of a stent coating manufactured in PVOH with and without the presence of carbon nanotubes with concentrations of CNT varying from 0.1 to 0.3% (Wt), through a computational study. The computational study is based on a Fluid-Structure (FSI) model in one way and with a scheme partitioned using the finite element method. In conclusion, predicting the mechanical behavior and local flow patterns of these devices may provide criteria elements that allow the improvement of the design of a stent coating

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Beshchasna, Natalia, Muhammad Saqib, Honorata Kraskiewicz, Łukasz Wasyluk, Oleg Kuzmin, Oana Cristina Duta, Denisa Ficai, et al. "Recent Advances in Manufacturing Innovative Stents." Pharmaceutics 12, no. 4 (April 13, 2020): 349. http://dx.doi.org/10.3390/pharmaceutics12040349.

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Cardiovascular diseases are the most distributed cause of death worldwide. Stenting of arteries as a percutaneous transluminal angioplasty procedure became a promising minimally invasive therapy based on re-opening narrowed arteries by stent insertion. In order to improve and optimize this method, many research groups are focusing on designing new or improving existent stents. Since the beginning of the stent development in 1986, starting with bare-metal stents (BMS), these devices have been continuously enhanced by applying new materials, developing stent coatings based on inorganic and organic compounds including drugs, nanoparticles or biological components such as genes and cells, as well as adapting stent designs with different fabrication technologies. Drug eluting stents (DES) have been developed to overcome the main shortcomings of BMS or coated stents. Coatings are mainly applied to control biocompatibility, degradation rate, protein adsorption, and allow adequate endothelialization in order to ensure better clinical outcome of BMS, reducing restenosis and thrombosis. As coating materials (i) organic polymers: polyurethanes, poly(ε-caprolactone), styrene-b-isobutylene-b-styrene, polyhydroxybutyrates, poly(lactide-co-glycolide), and phosphoryl choline; (ii) biological components: vascular endothelial growth factor (VEGF) and anti-CD34 antibody and (iii) inorganic coatings: noble metals, wide class of oxides, nitrides, silicide and carbide, hydroxyapatite, diamond-like carbon, and others are used. DES were developed to reduce the tissue hyperplasia and in-stent restenosis utilizing antiproliferative substances like paclitaxel, limus (siro-, zotaro-, evero-, bio-, amphi-, tacro-limus), ABT-578, tyrphostin AGL-2043, genes, etc. The innovative solutions aim at overcoming the main limitations of the stent technology, such as in-stent restenosis and stent thrombosis, while maintaining the prime requirements on biocompatibility, biodegradability, and mechanical behavior. This paper provides an overview of the existing stent types, their functionality, materials, and manufacturing conditions demonstrating the still huge potential for the development of promising stent solutions.

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Liu, Lan Xia, Xiao Hong Li, Chao Zhang, Xi Gang Leng, and Cun Xian Song. "Surface Modification of Coronary Stents for Intravascular Gene Delivery." Advanced Materials Research 668 (March 2013): 265–68. http://dx.doi.org/10.4028/www.scientific.net/amr.668.265.

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The present study investigated a novel surface modification on metal coronary stent for antibody immobilization. Methods: 316L stainless steel stents were surface modified with protein coatings. An Anti-DNA antibody was covalently bound to the protein surface using a bi-functional cross-linking agent SPDP. The artwork and binding stability of protein coatings were evaluated by in-vitro eluting. The feasibility and stability of anti-DNA antibody covalently bound to the stent were evaluated by means of 125I labeling. Results: We observed that pre-treating the steel surface using diluted HCL and increasing the ratio of cross-linking agent caused significantly increased binding stability of the protein coatings (p﹤0.001). The amount of chemically coupled antibody on the stents was 8 times higher than that of physically absorbed control stents. The stability of chemically coupled antibody on the stent was significantly better than physically absorbed control. Conclusion: It is concluded that we optimized the technique of protein coating on stainless steel and achieved stable anti-DNA antibody immobilization, therefore enabled efficient and highly localized non-viral gene delivery.

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Bocharov, Aleksandr V., and Leonid V. Popov. "Long-term results of stenting of long coronary artery stenosis with consecutive implantation of stents of different types with overlapping edges in patients with acute coronary syndrome without ST-segment elevation and multivessel coronary artery disease." Journal of Clinical Practice 10, no. 2 (August 17, 2019): 53–59. http://dx.doi.org/10.17816/clinpract10253-59.

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Introduction. In urgent interventional cardiology practice, combinations of drug-eluting stents and bare-metal stents are sometimes forced to treat extended stenosis in a clinic-dependent artery. Objective. A comparison of long-term results of treatment of patients with coronary heart disease and multivessel coronary lesions, which performed stenting of the clinic-dependent artery by two successive partially overlapping stents using stents of the 3rd generation with drug coating or a combination of the 3rd generation stent with drug coating and a bare-metal stent for acute coronary syndrome without St segment elevation and later — complete functional myocardial revascularization by endovascular method. Methods. The minimum overall length sentiremos section was made 55 mm. In main group included 32 patients for whom revascularization clinic-dependent artery performed endovascular intervention with the use of 2 stents 3-generation drug-coated sirolimus and biodegradable polymer implanted overlap. In 30 patients (control group), clinic-dependent artery revascularization was also performed by a combination of implanted overlap stents, one of which was a 3rd generation stent with sirolimus drug coating and biodegradable polymer, and the other was a bare-metal stent. There were no statistically significant differences between the groups in clinical, demographic and operational characteristics. Results. The analysis of the results revealed a significant difference between the groups in the frequency of repeated revascularization of the target artery, which were observed more often in the control group. Conclusion. When performing an extended stenting of the clinic-dependent artery in patients with acute coronary syndrome without ST segment elevation, overlapping of the drug-coated stent and the bare-metal stent should be avoided, since the antirestenotic effect of the drug-coated stent is leveled when overlapping with the bare-metal stent, but this strategy can be used in case of full coverage of the stenotic lesion or closure of the dissection.

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Asztalos, Lilla, and Krisztina Horicsányi. "Examination of Drug-eluting Coatings of Coronary Artery Stents." Acta Materialia Transylvanica 2, no. 2 (October 1, 2019): 73–78. http://dx.doi.org/10.33924/amt-2019-02-02.

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Abstract Drug-eluting stents provide a solution for treating restenosis in arteries expanded by using conventional bare metal stents, but there are a small number of publications on the processes of coating damage established due to the various effects that occur during the life cycle of the stent. In the current research damage to the coating was investigated along with the effects of damage on the corrosion resistance of the stent in multiple ways. This research investigates not only traditional drug eluting stents with polymer matrix, but also the new generation of polymer-free types.

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Gao, Lijian, Ce Zhang, Huanhuan Wang, Yiqun Zhang, Zhan Gao, Bo Xu, Jue Chen, Jinqing Yuan, Shubin Qiao, and Jilin Chen. "Scanning Electron Microscopic Assessment of Stent Coating Integrity in Jailed Wire Technique for Bifurcation Treatment." Journal of Interventional Cardiology 2021 (May 24, 2021): 1–5. http://dx.doi.org/10.1155/2021/2629393.

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Objectives. To assess the impact of different guidewires on stent coating integrity in jailed wire technique (JWT) for bifurcation treatment. Background. JWT is commonly adopted to protect side branch in provisional one-stent strategy for coronary bifurcation lesions. However, this technique may cause defects in stent coatings. The degree of coating damage caused by different types of jailed wires remains unknown. Methods. A fluid model with a bifurcation was established to mimic the condition in vivo. One-stent strategy was performed with three types of guidewire (nonpolymer-jacketed wire, intermediate polymer-jacketed wire, and full polymer-jacketed wire) tested for JWT. Scanning electron microscopy (SEM) was used to evaluate stent coating integrity and wire structure. The degrees of coating defects were recorded as no, slight, moderate, and severe defects. Results. A total of 27 samples were tested. Analyses of SEM images showed a significant difference in the degree of coating damage among the three types of wire after the procedure of JWT ( P < 0.001 ). Nonpolymer-jacketed wire could inevitably cause a severe defect in stent coatings, while full polymer-jacketed wire caused the least coating damages. Besides, there were varying degrees of coil deformation in nonpolymer-jacketed wires, while no surface damage or jacket shearing was observed in full polymer-jacketed wires. Conclusions. Although nonpolymer-jacketed wire has long been recommended for JWT, our bench-side study suggests that full polymer-jacketed wire may be a better choice. Further clinical studies are needed to confirm our findings.

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Delattre, Cécilia, Diego Velazquez, Caroline Roques, Graciela Pavon-Djavid, Véronique Ollivier, Anna Lokajczyk, Thierry Avramoglou, et al. "In vitro and in vivo evaluation of a dextran-graft-polybutylmethacrylate copolymer coated on CoCr metallic stent." BioImpacts 9, no. 1 (October 2, 2018): 25–36. http://dx.doi.org/10.15171/bi.2019.04.

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Introduction: The major complications of stent implantation are restenosis and late stent thrombosis. PBMA polymers are used for stent coating because of their mechanical properties. We previously synthesized and characterized Dextrangraft-polybutylmethacrylate copolymer (Dex-PBMA) as a potential stent coating. In this study, we evaluated the haemocompatibility and biocompatibility properties of Dex-PBMA in vitro and in vivo. Methods: Here, we investigated: (1) the effectiveness of polymer coating under physiological conditions and its ability to release Tacrolimus®, (2) the capacity of Dex-PBMA to inhibit Staphylococcus aureus adhesion, (3) the thrombin generation and the human platelet adhesion in static and dynamic conditions, (4) the biocompatibility properties in vitro on human endothelial colony forming cells ( ECFC) and on mesenchymal stem cells (MSC) and in vivo in rat models, and (5) we implanted Dex-PBMA and Dex-PBMATAC coated stents in neointimal hyperplasia restenosis rabbit model. Results: Dex-PBMA coating efficiently prevented bacterial adhesion and release Tacrolimus®. Dex-PBMA exhibit haemocompatibility properties under flow and ECFC and MSC compatibility. In vivo, no pathological foreign body reaction was observed neither after intramuscular nor intravascular aortic implantation. After Dex-PBMA and Dex-PBMATAC coated stents 30 days implantation in a restenosis rabbit model, an endothelial cell coverage was observed and the lumen patency was preserved. Conclusion: Based on our findings, Dex-PBMA exhibited vascular compatibility and can potentially be used as a coating for metallic coronary stents.

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Bhambri, Pallavi, Ali Sarvi, John H. Wong, Uttandaraman Sundararaj, and Alim P. Mitha. "Verapamil eluting stents as a possible treatment for vasospasm after subarachnoid hemorrhage." Journal of NeuroInterventional Surgery 9, no. 9 (July 29, 2016): 875–79. http://dx.doi.org/10.1136/neurintsurg-2016-012521.

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ObjectiveThe only pharmacologic prophylaxis for cerebral vasospasm after subarachnoid hemorrhage is oral nimodipine. A novel way to mitigate this risk may be to design a drug eluting stent that elutes verapamil over the time period typically associated with vasospasm. In this study, we explore different methods of coating nitinol stents with a bioabsorbable polymer and determine the release profile of various verapamil coated stents for the potential treatment of vasospasm.MethodsNitinol stents were coated with different concentrations of poly(lactic acid-co-glycolic acid) (PLGA) in chloroform solution and using three coating techniques: dip coating, spin coating, and electrospinning. Morphology of the coatings were studied with scanning electron microscopy. 12 verapamil eluting stents were then prepared using different verapamil concentrations and coatings with different numbers of layers. Drug release behaviors were studied using UV spectroscopy for 21 days.ResultsElectrospinning at 20% w/v resulted in a smooth uniform coating without significant surface irregularities, and may be the most effective technique to coat stents. Stents with a single layer of PLGA/verapamil coating showed a two phase release profile (initial burst release followed by a slow rate of release) whereas stents with a bilayer coating showed a lower level of initial release followed by a slower sustained release phase.ConclusionsDevelopment of verapamil eluting stents that elute drug over the time course typical of cerebral vasospasm, and for either immediate or prophylactic treatment, is technically feasible. Further in vitro and in vivo studies are required to determine whether this can improve the outcome of patients after subarachnoid hemorrhage.

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Gu, Xing Zhong, Hong Yi, Zhong Hua Ni, and Jian Hua Fang. "Drug-Eluting Coronary Stents Coated with Polysulfone-Poly(ethylene Oxide) Block Copolymer by Ultrasonic Spray." Key Engineering Materials 373-374 (March 2008): 633–36. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.633.

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Amphiphilic polysulfone-poly(ethylene oxide) block copolymers (PSF-b-PEOs) with different contents of PEO, have been successfully synthesized and employed as the drug carrier for use in drug-eluting stent (DES) systems. They are well soluble in organic solvents such as tetrahydrofuran (THF). Cell growth, hemolysis, cell hyperplasia, toxicity and sensitization tests revealed that PSF-b-PEOs have good biocompatibility. Silolimus was selected as the drug and the loading level was controlled at 10 or 20 wt%. PSF-b-PEO-coated stents were fabricated by the widely used ultrasonic spray coating technique. Pre- and post-expansion morphologies of the coatings were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Under the optimal operation conditions, the stents have uniform and smooth coating surface. No cracks or peels were observed when the coating stents were expanded. No drug particles were observed on the stent surface. PEO content in PSF-b-PEOs greatly influences drug release rate, and the higher the PEO content, the faster the release rate. PSF-b-PEO film comprising 30% PEO displayed relatively reasonable drug release rate, i.e., about 80% silolimus were released from the film after release tests in phosphate buffer solutions (PH = 7.4) containing 10 v% ethanol at 37 °C for 24 days.

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Pavlinich, Sergey, Xi Wei Liu, Li Da Hou, Hong Zhao, Zhen Li, and Li Li. "In Vitro Drug Release and Hemocompatibility of Biodegradable Plga/Peg Coated Paclitaxel-Eluting Stents." Advanced Materials Research 651 (January 2013): 49–53. http://dx.doi.org/10.4028/www.scientific.net/amr.651.49.

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The Paclitaxel-eluting stents (PTX) with biodegradable copolymer coating were studied in investigations. The polymer blend composition of PLGA (polylactic acid-co-glycolic acid) and PEG (poly ethylene glycol) have been applied as drug carrier and fabricated on the surface of 316L stainless steel stents by ultrasonic atomization spraying method. Were explored three doses: low-dose (~80μg per stent, 10 wt%), moderate-dose (~150μg per stent , 20 wt%), and high-dose (~220μg per stent , 30 wt%). The weight ratio of Paclitaxel to PLGA/PEG blends was 10:90, 20:80, and 30:70. Pre- and post-expansion surface morphologies of the Paclitaxel-eluting copolymer coating stents were examined by scanning electron microscopy (SEM). The quantitative analysis of Paclitaxel release in vitro and hemocompatibility by hemolysis ratio and dynamic clotting time measurement also were investigated.

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Grigore, Nicolae, Valentin Pirvut, Ionela Mihai, Adrian Hasegan, and Sebastian Ioan Cernusca Mitariu. "Side-Effects of Polyurethane Ureteral Stents with or without Hydrogel Coating in Urologic Pathology." Materiale Plastice 54, no. 3 (September 30, 2017): 517–19. http://dx.doi.org/10.37358/mp.17.3.4884.

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Ureteral stents represent one of the most utilized medical device in urology, as a minimally invasive alternative to preserve urine outflow. The ideal ureteral stent which combines long-term efficacy with a very low rate of side effects is still missing from the urologist armamentarium. The main material for ureteral stents production is polyurethane. In order to improve the side-effects and complications of polyurethane stents, special coatings were developed. The aim of this study is to evaluate short-term side-effects and complications of different polyurethane stents with or without coating used in urologic field.

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Gao, Junqing Q., Jianpu P. Zheng, Huigen G. Jin, Wenquan Q. Zhang, Pengyong Y. Yan, Tao Chen, and Zongjun J. Liu. "A new rapamycin-abluminally coated chitosan/heparin stent system accelerates early re-endothelialisation and improves anti-coagulant properties in porcine coronary artery models." Clinical & Investigative Medicine 37, no. 6 (December 1, 2014): 395. http://dx.doi.org/10.25011/cim.v37i6.22244.

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Purpose: Drug-eluting stents (DES) in percutaneous coronary intervention are more effective in preventing in-stent restenosis compared with bare metal stents (BMS); however, DES may cause late stent thrombosis, which has limited its use. In this study, the functional properties of a newly developed DES (RAP/CS/HEP), in which rapamycin was abluminally-loaded onto a chitosan/heparin coating stent (CS/HEP), were investigated in large animal artery injury models. Methods: The effectiveness of BMS, RAP (the traditional version of rapamycin DES), CS/HEP and RAP/CS/HEP stents in preventing coagulation and promoting re-endothelialisation was examined and compared in the porcine coronary artery models with arteriovenous shunt, high load thrombus and coronary balloon injury at day 7 and 28, respectively, after stent implantation. The re-endothelialisation on these stents was further evaluated in terms of endothelial gene expression using quantitative RT-PCR. Results: In the porcine coronary artery injury models, both RAP and RAP/CS/HEP stents were potent in reducing neointimal thickness, thus enlarging lumen area efficiently in the stented artery region compared with BMS and CS/HEP. RAP/CS/HEP stents facilitated re-endothelialisation and inhibited thrombosis more efficiently than BMS and RAP. Consistent with this, the expression of endothelial genes, such as CD31, CD34, eNOS and VEGF, was significantly elevated with RAP/CS/HEP stents compared with RAP and BMS stents. Conclusion: Abluminal coating of rapamycin onto the endothelialisation-accelerated CS/HEP stent and may prove to be an efficient treatment for tackling the late stent thrombosis associated with the traditionally circumferential RAP stent. This new RAP/CS/HEP stent system exhibits considerably improved therapeutic activity.

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Cirioni, Oscar, Roberto Ghiselli, Daniele Minardi, Fiorenza Orlando, Federico Mocchegiani, Carmela Silvestri, Giovanni Muzzonigro, et al. "RNAIII-Inhibiting Peptide Affects Biofilm Formation in a Rat Model of Staphylococcal Ureteral Stent Infection." Antimicrobial Agents and Chemotherapy 51, no. 12 (September 17, 2007): 4518–20. http://dx.doi.org/10.1128/aac.00808-07.

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ABSTRACT Ureteral stents coated with the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP) were implanted in rat bladders and shown to suppress Staphylococcus aureus formation on the stent and in urine and was especially effective when combined with teicoplanin. Coating ureteral stents with RIP thus increases the efficacy of teicoplanin in preventing ureteral stent-associated staphylococcal infections.

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Nazarkina, Zhanna K., Boris P. Chelobanov, Konstantin A. Kuznetsov, Alexey V. Shutov, Irina V. Romanova, Andrey A. Karpenko, and Pavel P. Laktionov. "Influence of Elongation of Paclitaxel-Eluting Electrospun-Produced Stent Coating on Paclitaxel Release and Transport through the Arterial Wall after Stenting." Polymers 13, no. 7 (April 5, 2021): 1165. http://dx.doi.org/10.3390/polym13071165.

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It was previously shown that polycaprolactone (PCL)-based electrospun-produced paclitaxel (PTX)-enriched matrices exhibit long-term drug release kinetics and can be used as coatings for drug-eluting stents (DES). The installation of vascular stents involves a twofold increase in stent diameter and, therefore, an elongation of the matrices covering the stents, as well as the arterial wall in a stented area. We studied the influence of matrix elongation on its structure and PTX release using three different electrospun-produced matrices. The data obtained demonstrate that matrix elongation during stent installation does not lead to fiber breaks and does not interfere with the kinetics of PTX release. To study PTX diffusion through the expanded artery wall, stents coated with 5%PCL/10%HSA/3%DMSO/PTX and containing tritium-labeled PTX were installed into the freshly obtained iliac artery of a rabbit. The PTX passing through the artery wall was quantified using a scintillator β-counter. The artery retained the PTX and decreased its release from the coating. The retention of PTX by the arterial wall was more efficient when incubated in blood plasma in comparison with PBS. The retention/accumulation of PTX by the arterial wall provides a prolonged drug release and allows for the reduction in the dose of the drugs in electrospun-produced stent coatings.

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Bae, In-Ho, Kyung Seob Lim, Dae Sung Park, Jae-Won Shim, So-Youn Lee, Eun-Jae Jang, Jun-Kyu Park, Ju-Han Kim, and Myung Ho Jeong. "Sirolimus coating on heparinized stents prevents restenosis and thrombosis." Journal of Biomaterials Applications 31, no. 10 (April 24, 2017): 1337–45. http://dx.doi.org/10.1177/0885328217706222.

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The aim of this study was to evaluate the inhibitory effect of sirolimus coating on the occurrence of restenosis and thrombosis with heparinized stents. Heparin and dopamine were conjugated by chemical bonding and anchored on the stent surface by a mussel-inspired adhesion mechanism. Subsequently, sirolimus was coated with poly lactic-glycolic acid on the heparinized stent surface. The heparin was well attached to the surface, and the surface was smooth after sirolimus coating. The smoothness of the surface was maintained after expansion of the stent. The amount of sirolimus released from the stent was 67.3% ± 4.55% within 7 days, followed by continual release up to day 28. The proliferation of smooth muscle cells was successfully arrested (51.3% ± 2.25% at 7 days of culture) by sirolimus released from the stent. Platelet adhesion was clearly prevented in the heparin-coated group (78.0 ± 8.00/1.8 cm2) compared to that in the heparin noncoated group (5.0 ± 1.00/1.8 cm2). Animal studies showed that the heparin and sirolimus-coated stent group had no obvious inflammatory response and no change in the fibrin score compared to those in the other groups. However, restenosis clearly decreased in the heparin and sirolimus-coated group (12.3% ± 3.54%) compared to the bare-metal stent group (27.5% ± 8.52%) and the heparin-coated group (25.3% ± 11.79%). These results suggest that heparinized surface-based sirolimus coating may be a useful approach for the prevention of restenosis and stent thrombosis.

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Ge, Shuang, Yadong Xi, Ruolin Du, Yuzhen Ren, Zichen Xu, Youhua Tan, Yazhou Wang, Tieying Yin, and Guixue Wang. "Inhibition of in-stent restenosis after graphene oxide double-layer drug coating with good biocompatibility." Regenerative Biomaterials 6, no. 5 (March 19, 2019): 299–309. http://dx.doi.org/10.1093/rb/rbz010.

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Abstract In this study, we designed a double layer-coated vascular stent of 316L stainless steel using an ultrasonic spray system to achieve both antiproliferation and antithrombosis. The coating included an inner layer of graphene oxide (GO) loaded with docetaxel (DTX) and an outer layer of carboxymethyl chitosan (CMC) loaded with heparin (Hep). The coated surface was uniform without aggregation and shedding phenomena before and after stent expanded. The coating treatment was able to inhibit the adhesion and activation of platelets and the proliferation and migration of smooth muscle cells, indicating the excellent biocompatibility and antiproliferation ability. The toxicity tests showed that the GO/DTX and CMC/Hep coating did not cause deformity and organ abnormalities in zebrafish under stereomicroscope. The stents with GO double-layer coating were safe and could effectively prevent thrombosis and in-stent restenosis after the implantation into rabbit carotid arteries for 4–12 weeks.

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Flight, Monica Hoyos. "A protective stent coating." Nature Reviews Drug Discovery 10, no. 12 (December 2011): 902. http://dx.doi.org/10.1038/nrd3604.

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Horicsányi, Krisztina, Lilla Asztalos, Dóra Károly, and Éva Fazakas. "Effect of Expansion Pressure on the Drug Eluting Coating and the Corrosion Characteristics of Coronary Stents." Acta Materialia Transilvanica 1, no. 1 (April 1, 2018): 37–40. http://dx.doi.org/10.2478/amt-2018-0012.

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Abstract During implantation, stents are delivered in crimped state to the narrowed lesion, where they are expanded to the desired size by the balloon. Due to insufficient size selection or high resistance to plaque, the stent is often widened by the expansion pressure to a level greater than the nominal pressure specified by the manufacturer. Depending on the degree of overpressure, the nominal diameter of the stent may change by several tenths of a millimetre. Numerous studies have dealt with the physiological effects of overexposure and stenogenic stress, but so far no studies have been carried out to investigate the stent coating and corrosion properties of the stent. In our research a widely used drug-eluting, platinum-chromium alloyed steel stent was observed with an inflation pressure of 12 and 18 bar. Scanning electron microscopy revealed lesions of the coating and potentiodynamic tests were performed to determine the corrosion rate.

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Michel, Eléonore, P. Chevallier, Amélie Barrère, Didier Letourneur, and D. Mantovani. "Polysaccharides Grafting on Fluorocarbon Films Deposited by Plasma on 316L Stainless Steel for Long Term Stable Stent." Advanced Materials Research 409 (November 2011): 164–69. http://dx.doi.org/10.4028/www.scientific.net/amr.409.164.

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Metallic intravascular stents are medical scaffolds commonly used to heal diseased arteries and to restore blood flow in vessels after a balloon angioplasty. Although clinical complications occurs (mainly in-stent-restenosis, representing 30-40% of cases within six months after angioplasty), this clinical procedure reduces the risk of restenosis. In order to improve the long-term clinical performances of stents, different coatings, bioactives or not, are investigated. However, the adhesion of the coating within the substrate is often weak and delamination after stent deployment could be observed. Therefore, our approach was to consider a plasma fluorocarbon film deposit on stainless steel substrates, improving adhesion and providing protection against the stent corrosion, as a carrier for the subsequent grafting of a polysaccharide (dextran). Indeed, a copolymer made of dextran and metacrylate has already demonstrated interesting results toward cell proliferation and appropriate mechanical properties regarding stent deployment. Hence, the aim of this project is to covalently graft the copolymer of dextran-methacrylate to plasma-aminated fluorocarbon film. In this study, dextrans were functionalized in order to conjugate them to amino groups. Two different ways of functionalization were investigated: by carboxylmethylation reaction and by periodate oxidation. Characterizations were performed by FTIR, for organic syntheses and by XPS for the subsequent grafting on the surface. Coatings topography and stability were also investigated. Preliminary results suggest the use of polysaccharides grafted by plasma on fluorocarbon films to provide a stable stent surface.

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Spinu, Arsenie Dan, Radu Dragos Marcu, Bogdan Socea, Camelia Cristina Diaconu, Ioan Scarneciu, Camelia Scarneciu, Oana Maria Bodean, et al. "Ureteral JJ Stent � Which One is Better?" Revista de Chimie 69, no. 8 (September 15, 2018): 2061–63. http://dx.doi.org/10.37358/rc.18.8.6473.

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Ureteral stents represent a minimally invasive alternative to preserve urinary drainage whenever the ureter is damaged or is under a significant risk to be occluded due to extrinsic or intrinsic etiology, even due to iatrogenic cause. Ureteral obstruction caused by extrinsic compression is often associated with intra-abdominal neoplasms. The first-line therapy to relieve such obstructions is usually internal drainage with ureteral stents. Ureteral stents made of different materials have been designed to achieve the best drainage possible. In this study, we tried to compare different JJ stent materials � which are better and their pros and cons. The ideal stent that would combine perfect long-term efficacy with no stent-related morbidity is still lacking and stent usage is associated with several adverse effects that limit its value as a tool for long-term urinary drainage. Several new ideas on stent design, composition material and stent coating are currently under evaluation, and are trying to eliminate the drawbacks of ureteral stent usage. Almost every clinician is familiar with the drawbacks that are associated with stents, including infection, encrustation, pain and discomfort.

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Jang, Sung Ill, and Dong Ki Lee. "Drug-eluting Biliary Stent." Korean Journal of Pancreas and Biliary Tract 25, no. 1 (January 31, 2020): 11–17. http://dx.doi.org/10.15279/kpba.2020.25.1.11.

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Biliary drainage is necessary to improve the survival or quality of life of patients with malignant biliary obstruction. In the past, surgery was the primary treatment for biliary drainage, but recently, endoscopic or percutaneous stent implantation has been recognized as the main treatment. Various materials and structures have been devised and developed to increase the patency of the biliary stent. In the development of these stents, drug-eluting biliary stents with an anti-tumoral agent (DES) have emerged to increase the stent patency period by chemically inhibiting tumor growth in the stent through the change of the coating material. The DESs have been proved to be stable through several animal and clinical trials, but their effectiveness has not been demonstrated. We will discuss the development process, problems, and future directions of DES that has been clinically applied.

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Strohbach, Anne, and Raila Busch. "Polymers for Cardiovascular Stent Coatings." International Journal of Polymer Science 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/782653.

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Polymers have found widespread applications in cardiology, in particular in coronary vascular intervention as stent platforms (scaffolds) and coating matrices for drug-eluting stents. Apart from permanent polymers, current research is focussing on biodegradable polymers. Since they degrade once their function is fulfilled, their use might contribute to the reduction of adverse events like in-stent restenosis, late stent-thrombosis, and hypersensitivity reactions. After reviewing current literature concerning polymers used for cardiovascular applications, this review deals with parameters of tissue and blood cell functions which should be considered to evaluate biocompatibility of stent polymers in order to enhance physiological appropriate properties. The properties of the substrate on which vascular cells are placed can have a large impact on cell morphology, differentiation, motility, and fate. Finally, methods to assess these parameters under physiological conditions will be summarized.

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Lukman, Siti Khadijah, Rania Hussien Al-Ashwal, Ahmad Zahran Md. Khudzari, and Syafiqah Saidin. "Emerging of cardiovascular metal stent: A review on drug-eluting stent towards the utilisation of herbal coating." Malaysian Journal of Fundamental and Applied Sciences 15, no. 2 (April 16, 2019): 225–31. http://dx.doi.org/10.11113/mjfas.v15n2.1115.

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Metal stents used in the treatment of percutaneous coronary intervention (PCI) have revolutionized in treating atherosclerosis disease. Starting from the emergence of bare metal stent (BMS), this stent has been progressively developed into drug-eluting stent (DES) and biodegradable stent. By focusing on DES, various drugs have been used to coat metal stent with the aims to overcome in-stent restenosis and stent thrombosis. Even though, both problems are covered successfully by DES, however, DES projects long term complications including late stent thrombosis and delayed endotheliasation. Therefore, the utilisation of various drugs and polymers as a coating material was reviewed in this study to identify possible alternative to overcome the current DES problems. Ginseng is one of the drugs which possess several beneficial properties for the development of DES. Review on its implementation in cardiovascular applications suggests its potential in promoting endotheliasation while inhibiting the growth of smooth muscle cell to prevent late stent thrombosis.

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Nelson, Stephen R., Nandita M. deSouza, and David J. Allison. "Endovascular Stents and Stent-Grafts: Is Heparin Coating Desirable?" CardioVascular and Interventional Radiology 23, no. 4 (June 15, 2000): 252–55. http://dx.doi.org/10.1007/s002700010064.

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Nazarkina, Zhanna K., Boris P. Chelobanov, Vera S. Chernonosova, Irina V. Romanova, Andrey A. Karpenko, and Pavel P. Laktionov. "Sirolimus-Eluting Electrospun-Produced Matrices as Coatings for Vascular Stents: Dependence of Drug Release on Matrix Structure and Composition of the External Environment." Materials 13, no. 12 (June 12, 2020): 2692. http://dx.doi.org/10.3390/ma13122692.

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Although a number of drug-eluting coatings for vascular stents (VSs) have been developed and are in commercial use, more efficient stent coatings and drug delivery systems are needed. Sirolimus (SRL) is a clinically important drug with antiproliferative and immunosuppressive activities that is widely used for coating stents. Here, we characterized SRL-enriched matrices, intended for coating vascular stents, that were produced by electrospinning (ES) on a drum collector from a solution of polycaprolactone (PCL) and human serum albumin (HSA), 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), dimethyl sulfoxide (DMSO), and SRL. The release of tritium-labeled SRL (3H-SRL) from matrices in phosphate-buffered saline (PBS) or human blood plasma (BP) was studied. The introduction of DMSO in the ES blend decreased SRL release. The use of BP significantly accelerated SRL release through binding with serum biomolecules. The exchange of PBS or BP after every time point also increased SRL release. The maximum SRL release in BP was observed at 3 days. The matrices produced from the ES solution with DMSO and HSA released no more than 80% SRL after 27 days in BP, even under medium exchange conditions. Therefore, PCL-based matrices containing HSA, SRL, and DMSO can be used for coating VSs with prolonged SRL delivery.

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Hou, Ruixia, Leigang Wu, Jin Wang, Zhilu Yang, Qiufen Tu, Xingcai Zhang, and Nan Huang. "Surface-Degradable Drug-Eluting Stent with Anticoagulation, Antiproliferation, and Endothelialization Functions." Biomolecules 9, no. 2 (February 18, 2019): 69. http://dx.doi.org/10.3390/biom9020069.

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Drug-eluting stents (DES) have been widely applied for saving the life of patients with coronary artery diseases (CADs). However, conventional polymers such as polylactic acid (PLA) and poly (lactic-co-glycolic acid) (PLGA), which are widely applied for drug-eluting stents studies, have serious bulk erosion problems, like high local acidity and poor mechanical properties. Instead, we chose surface erosion polymer poly (1, 3-trimethylene carbonate) (PTMC) as a drug carrier in this study. Here, we fabricated and characterized a novel durable-polymer drug-eluting 316 L stainless steel (SS) stent, in which the inner surface was coated with a Ti–O film using the magnetron sputtering method to promote the growth of endothelial cells (ECs). On the outer layer of the stent, first, a Ti–O film was deposited and, then, on top of it a rapamycin-loaded PTMC coat was deposited using the ultrasonic atomization spray method. This dual coating inhibited the migration and expansion of smooth muscle cells (SMCs). The drug coating also inhibited the adhesion/activation of platelets. In tests on dogs, it was found the novel stent promoted re-endothelialization and reduced restenosis, in contrast to the plain SS stent. Thus, the novel stent may have promise for use in treating patients with CAD.

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Feng, Hai Quan, Zhi Guo Wang, Yamashita Shuzou, and Nakatani Tatsuyuki. "Evaluation of the Adhesion of Diamond-Like-Carbon Coronary Stent." Advanced Materials Research 228-229 (April 2011): 714–18. http://dx.doi.org/10.4028/www.scientific.net/amr.228-229.714.

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The excellent biocompatibility and antithrombotic properties of Diamond-like Carbon films (DLC) have been widely confirmed in several clinical trials of artificial heart valves and blood vessels. In recent years many researchers were doing a lot of research coating DLC as the surface of coronary stents. Considering coronary stents’ plastic deformation occurred in installation and expansion process, surface coating was required to follow the plastic deformation of substrate materials, and it should be with excellent adhesion, without cracking and falling off. According to this, we created a method with different concentration gradient of silicon content on different thickness of DLC coating, and found a plastic deformation required by DLC coated stent, which with excellent adhesion and not cracking. In order to facilitate analysis and comparison, we compared it with two products abusing on the market under the same conditions and got a good result, which provided strong evidence for the product development of DLC coated coronary stents.

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Tan, Li-Li, Ke Yang, Bing Chun Zhang, and Yong Liang. "Study on Adhesion and Biocompatibility of Copolymer of MMA-BMA-MAA for Coronary Stents Coatings." Materials Science Forum 475-479 (January 2005): 2395–98. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.2395.

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Implantation of drug releasing coronary stents has been developed as an useful method for prevention of the restenosis in blood vessels. Copolymers of methyl methacrylate (MMA), butyl methacrylate (BMA) and methacrylic acid (MAA) were prepared as the coating polymer for drug releasing stent. The adhesion of the polymer with metal substrate and the biocompatibility were studied. Effect of the polymer composition on the adhesion between polymer coatings and metal substrate, as well as the effect of the polymer purification method on biocompatibility of the polymer, was studied. The results showed that the copolymer coating has good dry and wet adhesion properties, which can be improved by control of the polymer compositions. Biocompatibility of the prepared copolymer comes within the permission limit.

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Lewis, François, Benoit Maheux-Lacroix, Stephane Turgeon, and D. Mantovani. "Evaluation of the Adhesion of Ultra-Thin Teflon-Like Films Deposited by Plasma on 316L Stainless Steel for Long-Term Stable Drug-Eluting Stents." Advanced Materials Research 15-17 (February 2006): 119–24. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.119.

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Metallic intravascular stents are medical devices commonly made of 316L stainless steel or nitinol used to scaffold a biological lumen, most often diseased arteries, after balloon angioplasty. Stenting procedures reduce the risk of restenosis, but do not eliminate it completely. Indeed, restenosis remains the principal cause of clinical complications, leading to up to 30 % of failure after 3 months of implantation. During the last few years, several works have been focused on the development of an appropriate coating able to act as a carrier for specific anti-restenosis drugs. Moreover, this coating would act as an anti-corrosive barrier, thus inhibiting the release of potentially toxic ions. Actually, the main challenges in stent coatings are to synthesize a biocompatible polymer coating resistant to blood flow, wall shear stress and tensile force after the stent deployment which results in a permanent strain of up to 25%. The adhesion and chemical resistance after deployment are critical properties to investigate for the improvement of the long-term reliability of polymer coated stent. The aim of this study was to evaluate the effect of a 25% equivalent plastic deformation on chemical, mechanical and adhesion properties of Teflon-like films deposited on 316L stainless steel. These properties were studied by chemical spectroscopy and atomic force microscopy. Teflon-like films were deposited by pulsed plasma glow discharges on flat electropolished 316L stainless steel. An original method has been developed to induce the deformation, and preliminary results have showed that the 12 nm thick Teflon-like films successfully resist to deformations of up to 25%.

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Heublein, Bernd, Cem Özbek, and Klaus Pethig. "Silicon Carbide-Coated Stents: Clinical Experience in Coronary Lesions with Increased Thrombotic Risk." Journal of Endovascular Therapy 5, no. 1 (February 1998): 32–36. http://dx.doi.org/10.1177/152660289800500107.

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Purpose: To report the results of a prospective, nonrandomized, multicenter study of a semiconductor-coated stent in coronary lesions at high risk for stent thrombosis. Methods: A balloon-expandable tantalum stent was coated with silicon carbide to enhance thromboresistance (Tensum). Patients were enrolled in an observational study that compared coronary stenting with the Tensum stent in patients at low risk for stent thrombosis against those with factors predisposing to local thrombosis (acute myocardial infarction, small vessel diameter, recanalized chronic total occlusion, saphenous vein bypass grafts, and coronary allograft vascular disease). Results: In 294 patients with 364 coronary lesions, 111 patients with 142 lesions were assigned to the high-risk group. Overall, 406 Tensum stents were implanted (94% procedural success) using antiplatelet medication only after the procedure. The stent thrombosis rate (2.7% overall) in the high-risk group (3.6%) was not significantly different from that of the low-risk patients (2.1%). Conclusions: Silicon carbide coating on coronary stents may inhibit acute/subacute stent thrombosis even in patients at high risk. Randomized trials are underway for further evaluation of this promising coated stent.

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Touzin, Maryse, P. Chevallier, Stéphane Turgeon, Paula Horny, and D. Mantovani. "Evaluation of the Corrosion Protection of Ultra-Thin Plasma Fluorocarbon Film Deposited on 316L Stainless Steel for Long-Term Stable Stents." Materials Science Forum 638-642 (January 2010): 10–15. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.10.

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Commonly made of 316L stainless steel and nitinol, metallic intravascular stents are medical devices used to scaffold a biological lumen, most often diseased arteries. While stenting procedures reduce the risk of restenosis, they do not eliminate it completely. Furthermore, other common complications observed are thrombosis, inflammation and corrosion of the stents. The corrosion of the device is induced by blood flow which provokes a degradation of its mechanical properties and leads to a high risk of release of potentially toxic metallic compounds, such as nickel-based oxides and metal ions. To lower these clinical complication rates and to prevent the corrosion of the metallic stent structure, coated stents have been developed during the last decade. Indeed, the coating is expected to improve the surface biocompatibility and corrosion resistance without compromising the stainless steel mechanical properties required for the stent implantation. The Food and Drug Administration (FDA) has already provided guidance on a series of non-clinical test protocols, methods and reports to evaluate the safety and effectiveness of intravascular stents. Properties such as the stability, durability, and adhesion of a stent coating, prior and after deployment, must be clearly assessed to demonstrate its efficiency. This study wants to evaluate the effectiveness against general and local corrosion of an ultra-thin fluorocarbon film deposited by plasma on pre-treated stainless steel. Cyclic polarization tests were used to measure the coating capacity to protect the substrate from localized corrosion and Tafel plot corrosion measurements were used to evaluate the general corrosion behaviour of uncoated and coated, flat and deformed samples.

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Heublein, B., E. G. Evagorou, R. Rohde, S. Ohse, R. R. Meliss, S. Barlach, and A. Haverich. "Polymerized Degradable Hyaluronan – a Platform for Stent Coating with Inherent Inhibitory Effects on Neointimal Formation in a Porcine Coronary Model." International Journal of Artificial Organs 25, no. 12 (December 2002): 1166–73. http://dx.doi.org/10.1177/039139880202501208.

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Biodegradable hyaluronan (hyaluronic acid, HA) made insoluble by self-cross-linking in the presence of N-(3-dimethylaminopropyl)-N′-ethyl carbodiimide (EDC) has been used to cover stents. The maximum polymer-mass on a 16-mm stainless steel stent is approximately 2 mg. During manual crimping and simulated application, the loss of polymerized HA is negligible. The insoluble HA coating has an advantageous inherent antiproliferative effect regarding neointimal formation after local vessel wall injury (overstretch model) and leads to a reduced inflammatory response compared to uncoated stainless-steel stents, used as control, in undiseased pig coronary arteries, over a follow-up period of four weeks. Thus, cross-linked HA stent coating warrants further research as an interactive degradable biomaterial with an inherent inhibitory effect on neointimal formation as a possible biomatrix for local drug delivery to reduce restenosis rate.

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Bognár, Eszter, Tibor Balázs, György Ring, Barnabás Szabó, and Péter Nagy. "Stent Retention Measurement." Materials Science Forum 659 (September 2010): 283–88. http://dx.doi.org/10.4028/www.scientific.net/msf.659.283.

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This article introduces two original measurement methods (i.e. adhesive layer and pulloff edge) for the determination of the stent retention force, together with the results from these measurements. The measurement with the adhesive layer models and quantifies the stentobstruction occurring in the constrictions; meanwhile the pull-off edge method is based on modelling and quantifying the collisions and constrictions in the main catheter. For the evaluation of the measurements our research introduced the specific ‘stent pull-off’ force, which shows the force required for the ‘pull-off’ of the stent from the balloon, which is referred to as the stent unit length. This is the maximum force value shown on the retention diagram (insert diagram reference here). It is ascertainable, that the presence of the polyurethane coating and the increase of the pulling-speed are increasing the ‘stent pull-off’ force. During the test interval of the pull-off speed, the ‘stent pull-off’ force for the Chronoflex®-coated stents increased from 0.45 N/mm to 0.76 N/mm.

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das Neves, Rogério Coutinho, Márcia Renata Mortari, Elisabeth Ferroni Schwartz, André Kipnis, and Ana Paula Junqueira-Kipnis. "Antimicrobial and Antibiofilm Effects of Peptides from Venom of Social Wasp and Scorpion on Multidrug-Resistant Acinetobacter baumannii." Toxins 11, no. 4 (April 10, 2019): 216. http://dx.doi.org/10.3390/toxins11040216.

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Intravascular stent infection is a rare complication with a high morbidity and high mortality; bacteria from the hospital environment form biofilms and are often multidrug-resistant (MDR). Antimicrobial peptides (AMPs) have been considered as alternatives to bacterial infection treatment. We analyzed the formation of the bacterial biofilm on the vascular stents and also tested the inhibition of this biofilm by AMPs to be used as treatment or coating. Antimicrobial activity and antibiofilm were tested with wasp (Agelaia-MPI, Polybia-MPII, Polydim-I) and scorpion (Con10 and NDBP5.8) AMPs against Acinetobacter baumannii clinical strains. A. baumannii formed a biofilm on the vascular stent. Agelaia-MPI and Polybia-MPII inhibited biofilm formation with bacterial cell wall degradation. Coating biofilms with polyethylene glycol (PEG 400) and Agelaia-MPI reduced 90% of A. baumannii adhesion on stents. The wasp AMPs Agelaia-MPI and Polybia-MPII had better action against MDR A. baumannii adherence and biofilm formation on vascular stents, preventing its formation and treating mature biofilm when compared to the other tested peptides.

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Tittelbach, Michael, and Tobias Diener. "Orsiro – The First Hybrid Drug-eluting Stent, Opening Up a New Class of Drug-eluting Stents for Superior Patient Outcomes." Interventional Cardiology Review 6, no. 2 (2011): 142. http://dx.doi.org/10.15420/icr.2011.6.2.142.

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The Orsiro device is a hybrid drug-eluting stent that represents a new strategy in the treatment of coronary artery stenosis. Orsiro features a hybrid coating of passive and active components: the PROBIO passive coating seals the metal surface of the stent and prevents interaction with the surrounding blood and tissue, while the BIOlute active coating contains a highly biocompatible polymer that delivers a -limus drug over 12–14 weeks and degrades gently over one to two years, thereby avoiding increased inflammation. The stent backbone is the PRO-Kinetic Energy platform, which has a double-helix stent design and thin struts, bringing flexibility and ease of deliverability.

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Sudhir, Krishnankutty, James B. Hermiller, Joanne M. Ferguson, and Charles A. Simonton. "Risk Factors for Coronary Drug-Eluting Stent Thrombosis: Influence of Procedural, Patient, Lesion, and Stent Related Factors and Dual Antiplatelet Therapy." ISRN Cardiology 2013 (June 23, 2013): 1–8. http://dx.doi.org/10.1155/2013/748736.

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The complication of stent thrombosis (ST) emerged at a rate of 0.5% annually for first-generation drug-eluting stents (DES), often presenting as death or myocardial infarction. Procedural factors such as stent underexpansion and malapposition are risk factors for ST in patients. The type of lesion being treated and lesion morphology also influence healing after treatment with DES and can contribute to ST. Second-generation DES such as the XIENCE V everolimus-eluting stent differ from the first-generation stents with respect to antiproliferative agents, coating technologies, and stent frame. Improvements in stent structure have resulted in a more complete endothelialization, thereby decreasing the incidence of ST. Bioresorbable scaffolds show promise for restoring vasomotor function and minimizing rates of very late ST. Post-PCI treatment with aspirin and clopidogrel for a year is currently the standard of care for DES, but high-risk patients may benefit from more potent antiplatelet agents. The optimal duration of DAPT for DES is currently unclear and will be addressed in large-scale randomized clinical trials.

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Yamabe, Akane, Atsushi Irisawa, Yasuhito Kunogi, Ken Kashima, Kazunori Nagashima, Takahito Minaguchi, Akira Yamamiya, et al. "Development of biliary stent applying the antibacterial activity of silver: A literature review." Bio-Medical Materials and Engineering 32, no. 2 (March 23, 2021): 63–71. http://dx.doi.org/10.3233/bme-201163.

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BACKGROUND: Endoscopic transpapillary stenting is commonly performed in patients with obstructive jaundice caused by a biliary stricture. Although the plastic stent (PS) is widely used for biliary drainage because of the low-cost and easy procedure, patency is short after placement in the bile duct because of the small diameter. Dysfunction of PS is primarily caused by biliary sludge that forms as a result of bacterial adhesion and subsequent biofilm formation on the inner surface of the stent. It is well known that silver ions have excellent antibacterial activity against a wide range of microorganisms. OBJECTIVE: This review provides an overview and perspective of the significance of silver-coated biliary stents. METHODS: We collected literature regarding silver-coated biliary stents, reviewed the current research/development status and discussed their possible usefulness. RESULTS: To date, several in vivo/vitro studies evaluated the patency of silver-blended or silver-coated biliary stents. These studies suggested that the silver coating on a PS was likely to prolong the patency period. CONCLUSION: The development of biliary stents using silver is expected to prolong stent patency and prevent frequent stent replacement.

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Wieneke, Heinrich, Axel Schmermund, Clemens von Birgelen, Michael Haude, and Raimund Erbel. "Therapeutic potential of active stent coating." Expert Opinion on Investigational Drugs 12, no. 5 (May 2003): 771–79. http://dx.doi.org/10.1517/13543784.12.5.771.

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Trusov, Ivan S., Evgeniy M. Nifontov, Alexey V. Biryukov, Roman D. Ivanchenko, and Vadim V. Dobrovolskiy. "EFFECT OF THE DRUG COATING CHARACTERISTICS ON VASCULAR REMODELING: COMPARING THE LATEST GENERATIONS OF STENTS." Scientific Notes of the Pavlov University 26, no. 1 (August 23, 2019): 74–80. http://dx.doi.org/10.24884/1607-4181-2019-26-1-74-80.

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The basic method of myocardial revascularization in acute coronary syndrome is coronary stenting. Due to the high risk of later coronary events such as restenosis and late coronary thrombosis, studies on the different types of stents are currently underway.The objective was to evaluate the degree of neointimal coverage of stents with a permanent and biodegradable polymer in one patient.The patient with unstable angina was implanted 2 everolimus-containing stents with a constant polymer (Promus Premier) and a biodegradable polymer (Synergy). After 9 months, optical coherence tomography (OCT) was performed with the calculation of indicators.774 struts of the Synergy and 701 struts of the Promus Premier were analyzed. When evaluating the thickness of the formed neointima, no significant differences was obtained (p=0.47). At the same time, a greater number of uncovered struts were detected in the Promus Premier stent compared with Synergy stent (1.14 vs. 0 %, p = 0.002). The number of malposed uncovered struts was not statistically different (0.14 versus 0.13, p = 1.00), the difference in the number of malposed struts covered approaches statistically significant (1.14 versus 0.26, p = 0.0545).According to the results of optical coherence tomography, no significant differences between the studied platforms was obtained when assessing the late lumen loss. A greater number of uncovered struts in the stent with permanent polymer was detected, which could be considered as a risk factor for the development of late coronary thrombosis.

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Izsó, Izabella, and Lilla Asztalos. "Development Options for Coronary Stent Coatings." Acta Materialia Transylvanica 3, no. 2 (October 1, 2020): 70–75. http://dx.doi.org/10.33924/amt-2020-02-03.

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Abstract In our research we investigated the effect of different surface qualities on the adhesion of polylactic acid coating on 316L steel. During the study, samples were electropolished and surface treated with aqua regia and Vilella reagent, and the coating was applied by dipping technology using a Yaskawa robot arm. Tribology tests were carried out to determine the adhesion, in addition to the force and friction conditions, the coating damage resulting from the measurements was also recorded. In addition to the coating adhesion assay, contact angle measurements were also performed. Based on our measurement results, it was found that compared to the three different surface treatment methods, the surface of the samples treated with Villella was more adherent to the polymer than to the conventional electropolished surface. In this case, the frictional force was also much lower than that of the polished specimens, therefore this surface treatment method may be suitable for improving the adhesion of the coating.

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Ma, Ji, Teng-Fei Li, and Hui-Feng Yuan. "Novel Copper Nanoparticles Intercalated Polyurethane Heparin/Poly-L-Lysine Chelates Coated Stents: Viability Study for Coronary Vascular Cells and Aneurysms Treatments." Journal of Biomedical Nanotechnology 17, no. 2 (February 28, 2021): 216–29. http://dx.doi.org/10.1166/jbn.2021.3023.

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Continuous delayed endothelium regeneration and continues thrombosis development designate a task for coronary artery stent rehabilitation. To progress the direct vascular cell behavior, aneurysms treatments and compatibility of cardiovascular implants novel copper intercalated polyurethane heparin/poly-L-lysine chelates treated stent has established in this report. The functional group modifications, structural characteristics, and stability of the chelates have investigated for polyurethane heparin: poly-L-lysine, copper intercalated polyurethane heparin/poly-L-lysine coated stents. The FTIR results showed the copper intercalation at 446 cmr and the Cu 2s peak at 932 eV from XPS also indicated that the successful coating of copper, polyurethane heparin, poly-L-lysine. The relative surface geomorphology of the chelates displayed the uniform Cu coating consisting of multilayer poly-L-lysine on the substrate. The stability and biocompatibility studies indicated the significantly enhanced performance with clot the APTT and TT periods as clotting and cell proliferation assessments. This type of composite proposes a stage on a stent external area for discerning track of vascular cell performance and aneurysms treatments with low side effects.

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Gayle, Jessica, and Anil Mahapatro. "Magnesium Based Biodegradable Metallic Implant Materials: Corrosion Control and Evaluation of Surface Coatings." Innovations in Corrosion and Materials Science (Formerly Recent Patents on Corrosion Science) 9, no. 1 (September 24, 2019): 3–27. http://dx.doi.org/10.2174/2352094909666190228113315.

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Background:Magnesium and magnesium alloys are currently being explored for biodegradable metallic implants. Magnesium’s biocompatibility, low density, and mechanical properties could offer advantages in the development of low-bearing orthopedic prosthesis and cardiovascular stent materials.Objective:Magnesium’s susceptibility to corrosion and increased hydrogen evolution in vivo compromises the success of its potential applications. Various strategies have been pursued to control and subsequently evaluate degradation.Methods:This review provides a broad overview of magnesium-based implant materials. Potential coating materials, coating techniques, corrosion testing, and characterization methods for coated magnesium alloys are also discussed.Results:Various technologies and materials are available for coating magnesium to control and evaluate degradation. Polymeric, ceramic, metallic, and composite coatings have successfully been coated onto magnesium to control its corrosion behaviour. Several technologies are available to carry out the coatings and established methodologies exist for corrosion testing. A few magnesium-based products have emerged in international (European Union) markets and it is foreseen that similar products will be introduced in the United States in the near future.Conclusion:Overall, many coated magnesium materials for biomedical applications are predominantly in the research stage with cardiac stent materials and orthopaedic prosthesis making great strides.

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Journal articles on the topic 'Stent coating'

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