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

Mace, Amber

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

dc.contributor.author	Mace, Amber	en
dc.contributor.committeechair	Telionis, Demetri P.	en
dc.contributor.committeemember	Pyle, Robert Lee	en
dc.contributor.committeemember	Vlachos, Pavlos P.	en
dc.contributor.committeemember	Grant, John Wallace	en
dc.contributor.department	Engineering Science and Mechanics	en
dc.date.accessioned	2014-03-14T20:32:51Z	en
dc.date.adate	2003-05-07	en
dc.date.available	2014-03-14T20:32:51Z	en
dc.date.issued	2002-12-16	en
dc.date.rdate	2004-05-07	en
dc.date.sdate	2003-03-25	en
dc.description.abstract	Mechanical 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.degree	Master of Science	en
dc.identifier.other	etd-03252003-124256	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-03252003-124256/	en
dc.identifier.uri	http://hdl.handle.net/10919/31540	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	porcine_vorticity.avi	en
dc.relation.haspart	bileaflet_vorticity.avi	en
dc.relation.haspart	combination_vorticity.avi	en
dc.relation.haspart	thesis_mace.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	mitral leaflets	en
dc.subject	DPIV	en
dc.subject	St. Jude Medical	en
dc.subject	chordae tendineae	en
dc.subject	vorticity	en
dc.subject	mechanical heart valves	en
dc.title	A Comparative In Vitro Study of the Flow Characteristics Distal to Mechanical and Natural Mitral Valves	en
dc.type	Thesis	en
thesis.degree.discipline	Engineering Science and Mechanics	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en