Clarification of the pathophysiological mechanism associated with a total artificial heart (TAH) and establishment of optimum control method of TAH

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The objectives of this study are to clarify the mechanism of pathophysiological problems such as anemia, CVP elevation, low thyroid hormone, etc., generated during the total artificial heart pumping, and to establish an optimum control method of total artificial heart. The following results has been obtained in these 4 years.1. To improve the antithrombogenicity of the blood pump, a new polymer membrane valve, jellyfish valve, was developed. By using this valve the antithrombogenicity of the blood pump was improved greatly and many pathophysiological problems were disappeared, which would give us a hint to clarify the mechanism of pathophysiological problems. The valve was attracted attention internationally, and the cooperative research has begun with many laboratories in USA and Europe.2. We found that a strong nervous reflex occured in the goat when we cutoff an ascending aorta to connect a left outflow cannula, which had never been experienced when we connected the cannula to a des … More cending aorta.3. Concerning the renal functions, we found that renal plasma flow, renal blood flow, and glomerular filtration rate showed significantly decreases after TAH implantation and that the cause of these phenomena would be due to a CVP elevation.4. To seek the cause of CVP elevation, the influence of TAH on the dynamics of atrial natriuretic peptide (ANP) was studied. We found that although the secretion of ANP was not changed by TAH pumping, it did not increase when CVP increased, and that the natriuretic effect of ANP on the kidney was strongly suppressed in. TAH goats.5. As for the control of artificial heart, total right heart bypass and separate circulation between upper and lower half body with an artificial heart were carried out to clarify the control mechanism of the circulatory system and natural heart. Utilizing the results obtained from these experiments, a new automatic control method in which the output of TAH was controlled with the changes in total peripheral resistance. This method could keep a TAH animal in a good condition including exercise state and keep CVP in normal range. Less