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Ultrasonic and optical evaluation of surgical implant materials and devices. A durability study of pericardial bioprosthesesLaser Doppler Anemometry (LDA) and accelerated fatigue testing were used in an attempt to assess the durability of two cardiac value bioprostheses. The LDA system was used to monitor the function of the cardiac valves over time. This was done through flow characterization in an aortic flow chamber, designed to closely simulate in vivo conditions, both in the near vicinity (sinuses of valsalva region) and also somewhat downstream (aortic region) from the values. The accelerated fatigue tester was operated by opening and closing the valves at a rate of 1300 R.P.M., about 18 x the normal rate. The results from the two test valves indicate a definite change in the flow characteristics downstream from the valve after certain accelerated test intervals. The high velocity cross-sectional flow area seems to increase over time in use, causing a decrease in the peak velocity. The tissue became more flaccid in certain areas, and tears were apparent at about 9.4 million cycles for the Ionescu-Shiley valve and at 24 million cycles for the Carpentier-Edwards valve. The use of Doppler ultrasound as a technique for monitoring the function of bioprostheses over time in vivo is also discussed.
Document ID
19840018206
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Schuster, P. R. (Johns Hopkins Univ. Baltimore, MD, United States)
Date Acquired
September 4, 2013
Publication Date
May 1, 1984
Subject Category
Aerospace Medicine
Report/Patent Number
NASA-CR-173437
NAS 1.26:173437
Accession Number
84N26274
Funding Number(s)
CONTRACT_GRANT: NAG1-211
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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