Lévesque Julie, Hermawan Hendra, Dubé Dominique, Mantovani Diego
Laboratory for Biomaterials and Bioengineering, Department of Mining, Metallurgical and Materials Engineering, University Hospital Research Center, Laval University, Quebec City, Canada G1K 7P4.
Acta Biomater. 2008 Mar;4(2):284-95. doi: 10.1016/j.actbio.2007.09.012. Epub 2007 Oct 22.
Endovascular stents have proven effective in treating coronary and peripheral arterial occlusions. Since the first attempts, metals used to make these devices have been generally selected, and designed to be highly resistant to corrosion. Therefore, as almost the totality of metallic biomaterials, they are implanted on a long-term basis. However, complications associated with permanent stents, such as in-stent restenosis and thrombosis, have often been reported. In order to reduce those complications, it would be clinically useful to develop a new family of degradable stents. An interesting material for fabrication of degradable stents is based on magnesium, an essential element involved in human metabolism. Success in using magnesium alloys for the fabrication of endovascular devices is closely related to the properties of the selected alloy. In this context, a test bench was specifically designed to reproduce the physiological conditions to which stents are submitted when implanted in the coronary arteries. Then the test bench was validated using a magnesium-based alloy. Results showed that the corrosion rate and the corrosion mechanisms vary with the applied shear stress and that corrosion products strongly depend on the composition of the corrosive solution. This test bench will thus be useful in further investigations for the development of metallic alloys as degradable biomaterials.
血管内支架已被证明在治疗冠状动脉和外周动脉闭塞方面有效。自首次尝试以来，用于制造这些装置的金属通常经过挑选，并设计成具有高度耐腐蚀性。因此，与几乎所有金属生物材料一样，它们是长期植入的。然而，与永久性支架相关的并发症，如支架内再狭窄和血栓形成，经常被报道。为了减少这些并发症，开发一种新型可降解支架在临床上将是有用的。一种用于制造可降解支架的有趣材料是基于镁，镁是人体新陈代谢中涉及的一种必需元素。成功使用镁合金制造血管内装置与所选合金的性能密切相关。在这种情况下，专门设计了一个试验台来重现支架植入冠状动脉时所面临的生理条件。然后使用一种镁基合金对试验台进行了验证。结果表明，腐蚀速率和腐蚀机制随施加的剪切应力而变化，并且腐蚀产物强烈依赖于腐蚀溶液的成分。因此，这个试验台将有助于进一步研究开发作为可降解生物材料的金属合金。
