钴铬合金冠脉药物洗脱支架的弯曲疲劳实验

Experimental Study on Bent Fatigue Property of Co-Cr Coronary Drug Coated Stent

血管支架在经历4亿次体外循环加载后(等效于10年寿命周期),须保持长期的完整性而不会断裂或塌陷。由有限元分析得知Bu MA Supreme 4 mm×35 mm尺寸支架具有最差的疲劳寿命。本实验采用两种带有不同涂层的Bu MA Supreme 4 mm×35 mm支架以最大标签压依次打开呈15 mm曲率半径重叠放置在模拟血管中进行应变控制疲劳测试,实验频率分为加速55 Hz和实时1.2 Hz两种。实验结果表明Bu MA Supreme支架满足疲劳寿命的要求,实验中检测到极少量的微粒且几乎没有大尺寸微粒,验证了涂层支架在径向载荷下的长期完整性。

The stent must have long-term integrity without collapse or fracture after in vitro testing of at least 400 million cycles（10 year equivalent real time）. Stents were preconditioned prior to deployment in tubes of appropriate compliance. Overlapped Bu MA 4 mm×35 mm stents determined by FEA that represent the worst case size（with base layer and top coating） were subjected to strain controlled cycles under accelerated（55 Hz） and real time（1.2 Hz） conditions deployed to the maximum labeled diameter in mock tubes with a 15 mm radius of curvature static bent. Based on the test results, the Bu MA base-layer only coated stent passed the accelerated durability study and met the product specification. Chronic particulate testing of the Bu MA DES and BLO-coated stent demonstrate very low particle shedding with negligible release of large particles. Long-term integrity of the stent and any coating was demonstrated under cyclic radial loading conditions.