冠状动脉支架耐疲劳评价体系的研究

目的建立血管支架耐疲劳测试的评价体系。在我国对血管内支架体外的耐疲劳测试及相关评价还未开展,本文按照相关国际标准,设计了一套针对冠脉支架的耐疲劳的测试方法并建立相应的评价方法。方法测试条件近似模拟人体血管内环境：支架放置在乳胶管中,测试液体为37℃的NaCl溶液,径向应变接近人体自身血管内情况。整个测试在60Hz的频率下,进行了4×10^8个循环的加速疲劳试验,实验循环次数按70次.min-1的循环次数换算成人体时间相当于植入体内10年。并在此方法下,对3个厂家共12只冠脉支架进行耐疲劳测试后,分别用目视和游标卡尺检测直观形态;用扫描电镜对支架的整体结构和表面特征进行检查;用径向支撑力仪测试疲劳后支架力学强度。结果初步验证了疲劳评价方法,分别从形态学、力学的角度对疲劳试验后的支架进行了初步评价。通过研究初步建立了冠脉支架耐疲劳性能的评价体系。结论本方法对血管支架的安全性和有效性提供了合理的检测手段。

Study on the Evaluation Systems of Coronary Stents after Long Term Accelerating Fatigue Test in Vitro

Objective According to the related standards, a in vitro fatigue testing of coronary stents was designed and evaluating criteria was established. Methods The stents were fixed in latex tubes, which were full of 0. 9% saline solution and radial stress was produced so that to simulate nature vessel. The accelerated fatigue test was performed with 4×10^8 cycles at a frequency of 60 Hz, which was equal to 10 years in vivo implantation. Twelve coronary stents were adopted in the experiment. After fatigue test, the coronary stents were evaluated by four evaluating criteria. The bulk structure and surface morphology before and after fatigue test were analysed by scanning electron microscopy. The other evaluating criteria is potential and radial supporting force and holding power. Results This studay established testing methods of coronary stent fatigue. The fatigue evaluation methods were validated. Respectively, from point of the morphology and the mechanical view the stent after the fatigue test conducted a preliminary evaluation. The evaluation system of fatigue performance was initially established by studying the coronary stent. Conclusions The method provides a reasonable means for safety and efficacy testing of blood vessel stents.