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Squeeze flow measurements in mechanical heart valves
Chi-Wen Lo1, Po-Chien Lu, Jia-Shing Liu
1Department of Water Resources and Environmental Engineering, Tamkang University, Taipei, Taiwan.
ASAIO Journal (American Society for Artificial Internal Organs : 1992)
|March 22, 2008
Summary
Directly measured high-speed squeeze flow in mechanical heart valves. Velocities increased with heart rate, but may not solely cause cavitation, requiring further study.
Area of Science:
- Biomedical Engineering
- Cardiovascular Research
- Fluid Dynamics
Background:
- Mechanical heart valve closure generates high-speed squeeze flow.
- Cavitation is a suspected complication but difficult to measure in situ.
- Previous research relied on external measurements or computational fluid dynamics.
Purpose of the Study:
- To directly measure squeeze flow velocity within different mechanical heart valves.
- To investigate the relationship between heart rate and squeeze flow velocity.
- To explore the potential for cavitation during valve closure.
Main Methods:
- Utilized laser Doppler velocimetry for direct velocity measurements.
- Employed a mock circulation loop with St. Jude Medical (SJM), Omnicarbon (OC), and Medtronic Hall Standard (MHS) 29 mm valves.
- Incorporated quartz glass for laser penetration and strobe lighting for cavitation imaging.
Main Results:
- Squeeze flow velocity increased with higher heart rates across all tested valves.
- Measured velocities ranged from 2.39-3.44 m/s (SJM), 3.07-4.33 m/s (OC), and 3.87-5.33 m/s (MHS).
- Observed cavitation formation using strobe lighting.
Conclusions:
- Direct in-situ measurements of high-speed squeeze flow are feasible.
- Elevated velocities during valve closure may have implications for in vivo performance.
- Further investigation is needed to understand the pressure dynamics and cavitation mechanisms.
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