A Comparative In Vitro Study of the Flow Characteristics Distal to Mechanical and Natural Mitral Valves

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dc.contributor.authorMace, Amberen
dc.contributor.committeechairTelionis, Demetri P.en
dc.contributor.committeememberPyle, Robert Leeen
dc.contributor.committeememberVlachos, Pavlos P.en
dc.contributor.committeememberGrant, John Wallaceen
dc.contributor.departmentEngineering Science and Mechanicsen
dc.date.accessioned2014-03-14T20:32:51Zen
dc.date.adate2003-05-07en
dc.date.available2014-03-14T20:32:51Zen
dc.date.issued2002-12-16en
dc.date.rdate2004-05-07en
dc.date.sdate2003-03-25en
dc.description.abstractMechanical heart valve (MHV) flows are characterized by high shear stress, regions of recirculation, and high levels of turbulent fluctuations. It is well known that these flow conditions are hostile to blood constituents, which could lead to thromboembolism. In the ongoing effort to reduce long-term complications and morbidity, it is imperative that we better understand the flow characteristics of the natural valve as well as that of the mechanical valve. In this study, we overcome many of the limitations imposed by other measurement techniques by employing a powerful, high-speed Time-Resolved Digital Particle Image Velocimetry (TRDPIV) system to map the flow field. We compare the flows downstream from a St. Jude Medical bileaflet MHV, a porcine mitral valve (MV), and a combination of both valves to simulate the technique of chordal preservation. Instantaneous velocity fields and vorticity maps are presented, which provide detailed information about the development of the flow. Time-averaged velocity, vorticity, and turbulent kinetic energy measurements are also discussed. Asynchronous leaflet behavior was observed in all cases involving the mechanical valve. Extensive vortex formation and propagation are present distal to the MHV, which leads to high levels of jet dispersion. The porcine mitral jet exhibits lateral oscillatory behavior, but it does not disperse like the MHV. In the MHV/porcine combination system, the native tissue limits vortex propagation and jet dispersion. The results presented provide insight on the hemodynamic characteristics of natural and MHVs, reveal the detrimental character of asynchronous leaflet opening, document the mechanism of vortex formation and interaction distal to the valve, and illustrate the importance of chordal preservation. These results may improve MHV replacement clinical practice and/or motivate and aid the design of MHVs that better mimic natural mitral flow patterns.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-03252003-124256en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-03252003-124256/en
dc.identifier.urihttp://hdl.handle.net/10919/31540en
dc.publisherVirginia Techen
dc.relation.haspartporcine_vorticity.avien
dc.relation.haspartbileaflet_vorticity.avien
dc.relation.haspartcombination_vorticity.avien
dc.relation.haspartthesis_mace.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectmitral leafletsen
dc.subjectDPIVen
dc.subjectSt. Jude Medicalen
dc.subjectchordae tendineaeen
dc.subjectvorticityen
dc.subjectmechanical heart valvesen
dc.titleA Comparative In Vitro Study of the Flow Characteristics Distal to Mechanical and Natural Mitral Valvesen
dc.typeThesisen
thesis.degree.disciplineEngineering Science and Mechanicsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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