Document Detail

Pressure field in the vicinity of mechanical valve occluders at the instant of valve closure: correlation with cavitation initiation.
MedLine Citation:
PMID:  8061871     Owner:  NLM     Status:  MEDLINE    
In order to analyse cavitation dynamics during the closing phase of mechanical heart valve prostheses, an experimental study was performed to simulate a single closing event of the occluder with pressure measurements close to the occluder surface on the inflow side at the instant of valve closure. Cavitation bubble visualization was also performed using a stroboscopic lighting technique and photographic recording with tilting disc and bileaflet valve geometries. Large negative pressure transients were measured in the major orifice region of tilting disc valves and in the peripheral edges of bileaflet valves. The intensity of cavitation increased with increasing loading rate (transvalvular pressure rise rate) during the closing phase and with increasing valve size. The squeezing of fluid between the occluder and the seat stop or seating lip in the region where the occluder velocity at closure is at its maximum, and the resulting local flow dynamics are suggested as mechanisms for initiation of cavitation. The fluid forced through the clearance region due to the instantaneous large pressure difference across the occluder may be another source of large negative pressures and cavitation. The present in vitro study also suggests that cavitation may be the cause of platelet and red blood cell destruction, and ensuing thrombus formation associated with mechanical heart valves.
K B Chandran; C S Lee; L D Chen
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of heart valve disease     Volume:  3 Suppl 1     ISSN:  0966-8519     ISO Abbreviation:  J. Heart Valve Dis.     Publication Date:  1994 Apr 
Date Detail:
Created Date:  1994-09-22     Completed Date:  1994-09-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9312096     Medline TA:  J Heart Valve Dis     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  S65-75; discussion S75-6     Citation Subset:  IM    
Department of Biomedical Engineering, University of Iowa, Iowa City 52242.
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MeSH Terms
Blood Pressure
Heart Atria
Heart Valve Prosthesis*
Mitral Valve*
Models, Cardiovascular
Prosthesis Design
Stress, Mechanical
Surface Properties
Transducers, Pressure
Ventricular Pressure

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

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