Cools Bjorn, Brown Stephen, Wevers Martine, Humbeeck Jan Van, Boshoff Derize, Verdonckt Cis, Gewillig Marc
Pediatric and Congenital Cardiology, UZ Leuven, Leuven, Belgium.
Pediatric Cardiology, University of the Free State, Bloemfontein, South Africa.
Catheter Cardiovasc Interv. 2018 Feb 1;91(2):285-291. doi: 10.1002/ccd.27320. Epub 2017 Sep 12.
The aim of this study was to assess the resistance to compression (stiffness) of frequently used stents for right ventricular outflow tract prestenting. In addition, to assess the corrosion potential when different types of stent alloys come into contact with each other.
Different stents were tested in vitro in various combinations at specialized metallurgic laboratories. A bench compression test was used to assess resistance to compression of singular and joined combinations of stents. Corrosion was evaluated by standardized electrochemical galvanic tests in physiological solutions at 37°C. Single stents and combinations of stents were evaluated over a period of 4-12 weeks.
Relative stiffness of the stents Optimus/Andrastent XXL/Intrastent LD Max/8zig Cheatham-Platinum, expressed as load per length to deform the stent for 1 mm at 22 mm was 100/104/161/190. Adding additional stents to a single stent significantly strengthened the joined couples (P < 0.001). The lowest galvanic corrosion rates (about 0.000001 mm/year) were observed for the joined CP-Andrastent, Andra-Sapien, and Andra-SapienXT. The corrosion rate for coupled CP-Sapien and CP-SapienXT was somewhat higher (about 0.000003 mm/year). The materials with the highest corrosion rates resulted in material losses of, respectively, 17 and 24 µg/year, which is negligible over a lifetime.
Adding stents to a single stent significantly increases stiffness which will reduce the risk of metal fatigue failure. Corrosion of individual stents or stent combinations occurs, but is negligible over a human lifetime with low risk of biological effects. No mechanical integrity problems are thus expected as there is only 0.3% of the initial diameter of the struts of a stent that will be lost as a consequence of corrosion after 100 years.
本研究的目的是评估常用于右心室流出道预置入的支架的抗压缩性（刚度）。此外，评估不同类型的支架合金相互接触时的腐蚀电位。
在专业冶金实验室对不同的支架进行体外多种组合测试。采用台式压缩试验评估单个支架及连接组合的抗压缩性。通过在37℃生理溶液中的标准化电化学原电池试验评估腐蚀情况。对单个支架和支架组合进行4至12周的评估。
Optimus/Andrastent XXL/Intrastent LD Max/8zig Cheatham - Platinum支架的相对刚度，以在22mm处使支架变形1mm的每长度负载表示为100/104/161/190。在单个支架上添加额外的支架显著增强了连接对（P < 0.001）。连接的CP - Andrastent、Andra - Sapien和Andra - SapienXT观察到最低的原电池腐蚀率（约0.000001mm/年）。耦合的CP - Sapien和CP - SapienXT的腐蚀率略高（约0.000003mm/年）。腐蚀率最高的材料分别导致每年17和24μg的材料损失，在一生中可忽略不计。
在单个支架上添加支架显著增加刚度，这将降低金属疲劳失效的风险。单个支架或支架组合会发生腐蚀，但在人类一生中可忽略不计，生物效应风险低。因此预计不会出现机械完整性问题，因为100年后由于腐蚀，支架支柱初始直径仅会损失0.3%。
