Document Detail

The effect of tip angle on cavitation potential during closure of a bileaflet prosthesis model.
MedLine Citation:
PMID:  17702370     Owner:  NLM     Status:  MEDLINE    
BACKGROUND AND AIM OF THE STUDY: Mechanical heart valve (MHV) cavitation has been widely investigated by negative pressure transient (NPT) measurements. Whilst NPT is believed to be the cause of cavitation as the valve occluder approaches its fully closed position, some valves are also more prone to cavitation initiation. The study aim was to determine the effect of tip angle on the occluder trailing edge for the MHV closure flow field and cavitation potential. METHODS: Three pairs of 1:1 transparent bileaflet models, with different tip angles (30 degrees, 60 degrees and 90 degrees), were used in a pulsatile mock loop. Particle image velocimetry (PIV) and micro-tip pressure catheters were applied respectively for the closure flow and transient pressure investigations. A mechanism was designed to enable triggering when the valve occluder approached its closing position. RESULTS: The transient pressure showed two maximum pressure drops, the magnitudes of which differed with various angle designs. A series of flow fields with continuously narrowing gap channels was captured. Different flow features were demonstrated for the three valve models. CONCLUSION: The tip angle design on the occluder trailing edge affected both the NPT magnitude and MHV closure flow field. The 60 degrees and 30 degrees valves had higher vorticity and fluid deceleration rate within the squeeze flow and occluder sudden stop respectively, which correlated with their larger pressure drops for the first and second NPT peaks.
Pei Zhang; Joon Hock Yeo; Ping Qian; Ned H C Hwang
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of heart valve disease     Volume:  16     ISSN:  0966-8519     ISO Abbreviation:  J. Heart Valve Dis.     Publication Date:  2007 Jul 
Date Detail:
Created Date:  2007-08-17     Completed Date:  2007-10-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9312096     Medline TA:  J Heart Valve Dis     Country:  England    
Other Details:
Languages:  eng     Pagination:  430-9     Citation Subset:  IM    
School of Mechanical & Automation Engineering, Shanghai Institute of Technology, China.
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MeSH Terms
Blood Flow Velocity / physiology*
Equipment Failure Analysis
Heart Valve Prosthesis*
Models, Cardiovascular
Prosthesis Design
Pulsatile Flow / physiology*
Ventricular Pressure / physiology

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

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