Influence of the Implant Location on the Hinge and Leakage Flow Fields 
Through Bileaflet Mechanical Heart Valves

Simon, Helene A.

Title:

Influence of the Implant Location on the Hinge and Leakage Flow Fields Through Bileaflet Mechanical Heart Valves

dc.contributor.advisor	Yoganathan, Ajit P.
dc.contributor.author	Simon, Helene A.	en_US
dc.contributor.committeeMember	Sambanis Athanassios
dc.contributor.committeeMember	Sotiropoulos Fotis
dc.contributor.department	Chemical Engineering	en_US
dc.date.accessioned	2005-03-03T21:53:24Z
dc.date.available	2005-03-03T21:53:24Z
dc.date.issued	2004-04-08	en_US
dc.description.abstract	Native heart valves that have limited functionality due to cardiovascular disease or congenital birth defects are commonly replaced by prosthetic heart valves. Bileaflet mechanical heart valves (BMHV) are the most commonly implanted valve design due to their long-term durability. However, their unnatural hemodynamics promote thrombosis and thromboembolic events. Clinical reports and in vitro experiments suggest that the thrombogenic complications in bileaflet valves are related to the stress imposed on blood by the valves during the closing phase. Additionally, animal and clinical studies have shown that BMHV in the aortic position demonstrate reduced failure rates compared to identical valves in the mitral position. The present study aimed to investigate the leakage, hinge, and near hinge flow fields of two BMHV under simulated physiologic aortic flow conditions and to compare these results with previous findings in the mitral position to better understand how the implant location influences the valve performance and the subsequent risk of blood damage. Two and three-component Laser Doppler Velocimetry techniques were used to quantify the velocity and turbulent shear stress fields in both the hinge and the upstream leakage flow regions. The study focused on the 23 mm St. Jude Medical Regent (SJM) and the 23 mm CarboMedics (CM) valves. Although they were tested under similar physiologic conditions, shape and location of the leakage jets were dependent on valve design. Nevertheless, turbulent shear stress levels recorded within all jets were well above the threshold shear stress for the onset of blood cell damage. Within the hinge region, the flow fields were complex and unsteady. The angulated hinge recess of the CM valve appeared to promote blood damage while the streamlined geometry of the SJM valve contributed to better washout of the hinge region. Animations of the velocity flow fields are given in QuickTime or MPEG format. Comparison of the present findings with previously published results for the mitral position suggests that the superior clinical results of the mechanical valves in the aortic position may be due to less severe leakage flow upon valve closure as well as to enhanced hinge washout during the forward flow phase.	en_US
dc.description.degree	M.S.	en_US
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dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/mpeg
dc.format.mimetype	video/quicktime
dc.format.mimetype	video/mpeg
dc.format.mimetype	video/quicktime
dc.format.mimetype	application/pdf
dc.identifier.uri	http://hdl.handle.net/1853/5159
dc.language.iso	en_US
dc.publisher	Georgia Institute of Technology	en_US
dc.subject	Laser Doppler velocimetry	en_US
dc.subject	Thrombosis
dc.subject	Hinge
dc.subject	Implant location
dc.subject	CarboMedics valve
dc.subject	St. Jude Medical Regent valve
dc.subject	Leakage jets
dc.title	Influence of the Implant Location on the Hinge and Leakage Flow Fields Through Bileaflet Mechanical Heart Valves	en_US
dc.type	Text
dc.type.genre	Thesis
dspace.entity.type	Publication
local.contributor.advisor	Yoganathan, Ajit P.
local.contributor.corporatename	School of Chemical and Biomolecular Engineering
local.contributor.corporatename	College of Engineering
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