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1
Content available remote Analysis of selected utility properties of biomaterials used in coronary stents
Jurkiewicz W., Paszenda Z., Basiaga M., Walke W.
Journal of Achievements in Materials and Manufacturing Engineering
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2013
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Vol. 56, nr 1
7--13
EN
Purpose: The study analysed influence of the selected functional properties of metallic biomaterials on selected functional properties of coronary stents used in invasive cardiology. Design/methodology/approach: Pitting corrosion resistance tests were performed by means of potentiodynamic method. Corrosion resistance tests were performed on the ground of registered anodic polarisation curves and Stern method. The research also comprised galvanic corrosion resistance tests with application of Evans method. Measurements were made with VoltaLab® PGP 201 system. Tests were performed in artificial blood plasma at the temperature T = 37.0±1°C and pH = 7.0±0.2. Measurements of fluoroscopic visibility with application of cardiovascular imaging system Integris 5000 by Philips were also performed. Findings: Application of Ta layer in composite stents made of Cr-Ni-Mo steel is an effective method used for improvement of their functional properties, and in particular of their fluoroscopic visibility, at the same time decreasing their corrosion resistance. It is of crucial meaning for increasing effectiveness and safety of low-invasive percutaneous transluminal coronary angioplasty. Practical implications: Improvement of fluoroscopic visibility of coronary stents is possible through application of materials with increased X-ray absorptivity for their production. Within this scope you can consider certain form of implant created as a whole from one biomaterial or mixture of two biomaterials (layer implants), on the assumption that one of them features greater X-ray absorptivity. Originality/value: Application of middle layer made of tantalum in composite stent does not influence initiation of galvanic corrosion process but it produces better fluoroscopic visibility that brings forth improved safety of coronary angioplasty.
2
Content available remote Physical properties and haemocompatibility of passive-carbon layer
Paszenda Z., Tyrlik-Held J., Jurkiewicz W.
Journal of Achievements in Materials and Manufacturing Engineering
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2008
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Vol. 31, nr 2
348-355
EN
Purpose: In the paper physical (surface topography, electrical properties) and antithrombogenic properties of the passive-carbon layer used for enhancing the surface properties of vascular stents made of Cr-Ni-Mo steel have been investigated. Design/methodology/approach: To characterize the electrical properties of carbon layer the silicon plate was used. The resistivity ρ and relative permittivity of the layer ε r have been determined on the basis of currentvoltage and capacitance-voltage characteristics. In vitro tests of biotolerance evaluation of the passive-carbon layer in blood environment have been carried out in the haemolysis tests (in the direct contact and from the extract) and in the blood clotting tests. Findings: The results of investigations have shown that deposition process of the passive-carbon layer of dielectric properties on the surface of implants made of Cr-Ni-Mo steel and used in interventional cardiology is an effective way of limiting the reactivity of their surface in blood environment and the blood clotting process in consequence. Research limitations/implications: Usefulness of the passive-carbon layer for interventional cardiology applications should be verified in in vivo tests. Originality/value: Modification of physical properties of surface of the metallic biomaterials applied in cardiovascular system by deposition of the passive-carbon layer which has dielectric properties limits the blood clotting process.
3
Content available Odporność korozyjna stentów naczyniowych z biomateriałów metalowych
Walke W., Jurkiewicz W., Paszenda Z., Pochrząst M.
Engineering of Biomaterials
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2008
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Vol. 11, no. 77-80
43--45
4
Content available remote Biomechanical behaviour of coronary stent design with OCC technology
Walke W., Paszenda Z., Jurkiewicz W.
Journal of Achievements in Materials and Manufacturing Engineering
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2007
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Vol. 20, nr 1-2
199-202
EN
Purpose: The work presents results of stresses and strains of three-layer vascular stent (Cr-Ni-Mo - Ta - Cr-Ni-Mo) and one-layer uniform one (Cr-Ni-Mo) used in operative cardiology. Design/methodology/approach: On the basis of the geometrical model a finite element mesh was generated. The discretization process was realized with the use of the SOLID95 element. The set boundary conditions represented the phenomena which occur during baloon expanding. Findings: The numerical analysis of the three-layer stent showed diverse distribution of stresses and strains in the individual layers. Minimum stresses in the analyzed range of expansion diameters (d=2.25-3.50 mm) were observed in the middle layer made of tantalum. Maximum stresses were observed in the layer made of the stainless steel. Research limitations/implications: Values of stresses and strains in different stents' regions caused by applied displacements are valuable information for appropriate design of the geometry, hardening of the metallic biomaterial and forming of physio-chemical properties of surface layer. Originality/value: The obtained results are valuable for selection of surface layer which is mainly responsible for ensuring proper hemocompatibility of the stent. The deformable surface layer is an effective way to reduce the surface reactivity of the stent in blood environment and in consequence coagulation.
5
Content available remote Investigations of antithrombogenic properties of passive-carbon layer
Paszenda Z., Tyrlik-Held J., Jurkiewicz W.
Journal of Achievements in Materials and Manufacturing Engineering
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2006
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Vol. 17, nr 1-2
197--200
EN
Purpose: The main purpose of the paper was evaluation of antithrombogenic properties of the passive-carbon layer used for enhancing the surface properties of vascular stents made of Cr-Ni-Mo steel. Design/methodology/approach: In vitro tests of biotolerance evaluation of the passive-carbon layer in blood environment have been carried out on the basis of haemolysis tests (in the direct contact and from the extract) and blood clotting tests. Findings: The carried out investigations have shown that deposition process of the passive-carbon layer which has dielectric properties on the surface of implants made of Cr-Ni-Mo steel and used in interventional cardiology is an effective way in limiting the reactivity of their surface in blood environment and the blood clotting process in consequence. Research limitations/implications: The carried out investigations should be completed with biotolerance in vivo investigations. Originality/value: Modification of physical properties of surface of the metallic biomaterials applied in cardiovascular system by deposition of the passive-carbon layer of dielectric properties limits the blood clotting process.
6
Content available Charakterystyka biomechaniczna stentu wieńcowego z technologią OCC
Walke W., Paszenda Z., Jurkiewicz W.
Inżynieria Biomateriałów
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2006
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R. 9, nr 58-60
209-211
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