A preliminary durability study of two types of low-profile pericardial bioprosthetic valves through the use of accelerated fatigue testing and flow characterization
✍ Scribed by Schuster, Paul R. ;Wagner, James W.
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 908 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Bioprosthetic heart valves are being used more often because of certain advantages they have over artificial valves. The bioprostheses are less thrombogenic, cause a lower incidence of hemolysis, and usually fail in a slow progressive manner. A combination of flow characterization and accelerated testing was used to assess the durability of two types of pericardial valves, the Ionescu-Shiley Low Profile Mitral and the Carpentier-Edwards Low Profile Aortic valve. The flow characterization work was done in an aortic chamber designed for in vivo simulation. The function of the valve was monitored be-tween different stages of the accelerated testing using laser Doppler anemometry. Accelerated testing was performed at 1300 cardiac cycles per minute, and physiologic conditions both in closing pressures and the ambient temperature were maintained. Results indicated a change in flow characteristics owing to cyclic loading of the leaflet tissue. The flow orifice increased over time leading to a decrease in peak velocity. Future developments in Doppler ultrasound may facilitate non-invasive assessment of these peak velocity variations. Calcification of the tissue was not considered, since this was an in vitro study.