Document Detail


Reduction of procoagulant potential of b-datum leakage jet flow in bileaflet mechanical heart valves via application of vortex generator arrays.
MedLine Citation:
PMID:  20590289     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Current designs of bileaflet mechanical heart valves put patients at an increased risk of thromboembolism. In particular, regurgitant flow through the b-datum line is associated with nonphysiologic flow characteristics such as elevated shear stresses, regions of recirculation, and increased mixing, all of which may promote thrombus formation. We have previously shown that passive flow control in the form of vortex generators mounted on the downstream leaflet surfaces can effectively diminish turbulent stresses. The objective of the current work is thus to determine the effect of vortex generators on the thromboembolic potential of the b-datum line leakage jet and to correlate that effect with the vortex generator-induced changes to the flow structure. Flow experiments were performed using a steady model of the transient b-datum line jet. These experiments encompassed flow visualization to gain an overall picture of the flow system, particle image velocimetry to quantify the flow field in detail, and in vitro experiments with human blood to quantify thrombus formation in response to the applied passive flow control. Thrombus formation was quantified over time by an assay for thrombin-antithrombin III (TAT III). In comparing results with and without vortex generators, significantly lower mean TAT III levels were observed at one time point for the case with vortex generators. Also, the TAT III growth rate of the case with vortex generators was significantly lower. While no differences in jet spreading were found with and without vortex generators, lower peak turbulent stresses were observed for the case with vortex generators. The results thus demonstrate the potential of applying passive flow control to cardiovascular hardware in order to mitigate the hemodynamic factors leading to thrombus formation.
Authors:
David W Murphy; Lakshmi P Dasi; Jelena Vukasinovic; Ari Glezer; Ajit P Yoganathan
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of biomechanical engineering     Volume:  132     ISSN:  1528-8951     ISO Abbreviation:  J Biomech Eng     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-07-01     Completed Date:  2010-10-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7909584     Medline TA:  J Biomech Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  071011     Citation Subset:  IM    
Affiliation:
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Female
Heart Valve Prosthesis / adverse effects*
Heart Valves
Hematologic Agents / adverse effects*
Hemodynamics
Humans
Male
Physical Processes
Rheology / instrumentation*
Stress, Mechanical
Thromboembolism / complications,  etiology*
Thrombosis / etiology
Chemical
Reg. No./Substance:
0/Hematologic Agents

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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