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Abstracts: ASAIO Bioengineering/tissue Engineering Abstracts

CHARACTERIZATION OF NUCLEI CONTENT FOR MECHANICAL HEART VALVE CAVITATION

Barrett, Brian C1; Manning, Keefe B1; Fontaine, Arnold A1; Tarbell, John M2; Deutsch, Steven1

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Cavitation occurs in vivo as a result of mechanical heart valve closure. Controversy exists regarding the cause of cavitation and whether blood has enough nuclei for cavitation formation. The nuclei content of blood and blood analogs has not been studied in great detail. The goal is to address this problem and better characterize the nuclei content. In order to do this, cavitation is induced in a controlled environment using a Cavitation Susceptibility Meter (CSM) or venturi. The fluids are run through the CSM and the flow rate and pressure measured. Cavitation occurs in the throat region of the CSM and the acoustical signal of each event can be detected using an accelerometer mounted at the throat. Nuclei of different size and number are detected. The initial and critical radii are calculated. Once the fluids have been characterized, they are tested in a mechanical heart valve single shot chamber, which simulates mitral valve closure dynamics, in order to make correlations to cavitation in vitro. Data is present for tap water, degassed tap water, and carbon dioxide supplemented degassed water. As suspected, degassing the tap water reduced the number of nuclei per liter by more than half. The majority of nuclei in both cases are in the range of 0.5–1.0 μm. Supplementing the degassed water with carbon dioxide results in increased nucleation sites, in the range of 0.8–1.6 μm.

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