Squeeze flow measurements in mechanical heart valves

doi:10.1097/MAT.0b013e3181648da0

機構典藏 > College of Engineering > Graduate Institute & Department of Water Resources and Environmental Engineering > Journal Article > Item 987654321/50732

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Title:	Squeeze flow measurements in mechanical heart valves
Authors:	Lo, Chi-wen;盧博堅;Lu, Po-chien;Liu, Jia-shing;Li, Chi-pei;Hwang, Ned H.
Contributors:	淡江大學水資源與環境工程學系
Date:	2008-03
Issue Date:	2010-08-10 15:53:25 (UTC+8)
Publisher:	Philadelphia: Lippincott Williams & Wilkins
Abstract:	High-speed squeeze flow during mechanical valve closure is often thought to cause cavitation, either between the leaflet tip and flat contact area in the valve housing, seating lip, or strut flat seat stop, depending on design. These sites have been difficult to measure within the housing, limiting earlier research to study of squeeze flow outside the housing or with computational fluid dynamics. We directly measured squeeze flow velocity with laser Doppler velocimetry at its site of occurrence within the St. Jude Medical (SJM), Omnicarbon (OC), and Medtronic Hall Standard (MHS) 29 mm valves in a mock circulation loop. Quartz glass provided an observation window to facilitate laser penetration. Our results showed increasing squeeze flow velocity at higher heart rates: 2.39-3.44 m/s for SJM, 3.07-4.33 m/s for OC, and 3.87-5.33 m/s for MHS. Strobe lighting technique captured the images of cavitation formation. Because these results were obtained in a mock circulation loop, one can assume this may occur in vivo resulting in valve damage, hemolysis, and thromboembolism. However, velocities of this magnitude alone cannot produce the pressure drop required for cavitation, and the applicability of the Bernoulli equation under these circumstances requires further investigation.
Relation:	ASAIO Journal 54(2), pp.156-162
DOI:	10.1097/MAT.0b013e3181648da0
Appears in Collections:	[Graduate Institute & Department of Water Resources and Environmental Engineering] Journal Article

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