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A Physical Model Describing the Mechanism for Formation of Gas Microbubbles in Patients with Mitral Mechanical Heart Valves

Rambod, Edmond and Beizaie, Masoud and Shusser, Michael and Milo, Simcha and Gharib, Morteza (1999) A Physical Model Describing the Mechanism for Formation of Gas Microbubbles in Patients with Mitral Mechanical Heart Valves. Annals of Biomedical Engineering, 27 (6). pp. 774-792. ISSN 0090-6964. doi:10.1114/1.231.

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This study was aimed at developing a physical model, supported by experimental observations, to describe the formation and growth of microbubbles seen in patients with mitral mechanical heart valves (MHV). This phenomenon, often referred to as high intensity transient signals (HITS), appears as bright, intense, high-velocity and persistent echoes detected by Doppler ultrasonography at the instant of closure. The long-term clinical implications of HITS has yet to be determined. However, there are reports of a certain degree of neurological disorder in patients with mitral MHV. The numerical analysis has shown the existence of a twofold process (1) nucleation and (2) microbubble growth as a result of cavitation. While mild growth of nuclei is governed by diffusion, explosive growth of microbubbles is controlled by pressure drop on the atrial side of mitral MHV. It was demonstrated that there exist limits on both microbubble size and regurgitant velocity, above which microbubbles grow explosively, and below which growth is almost nonexistent. Therefore, prevention of excessive pressure drops induced by high closing velocities related to the dynamics of closure of mitral MHV may offer design changes in the future generations of mechanical valves.

Item Type:Article
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URLURL TypeDescription DOIArticle
Gharib, Morteza0000-0003-0754-4193
Additional Information:© 1999 Biomedical Engineering Society. Received 1 March 1999; accepted 23 August 1999. The authors would like to acknowledge the CVS Division of Baxter Healthcare Corporation in Irvine, California for providing some of the valves studied in this work. This study was conducted under a general research grant from the Powell Foundation.
Funding AgencyGrant Number
Charles Lee Powell FoundationUNSPECIFIED
Subject Keywords:mechanical heart valves; cavitation; nucleation; microbubble growth; HITS
Issue or Number:6
Record Number:CaltechAUTHORS:20130912-080452185
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41268
Deposited By: Tony Diaz
Deposited On:13 Sep 2013 16:25
Last Modified:10 Nov 2021 04:27

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