1989 Fiscal Year Final Research Report Summary
BASIC RESEARCH ABOUT THE CLINICAL APPLICATION OF THE ARTIFICIAL HEART FOR THE BRIDGING USE OF THE HEART TRANSPLANTATION
| Project/Area Number |
63570656
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thoracic surgery
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| Research Institution | Tohoku University |
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Principal Investigator |
NITTA Shin-ichi Dept. of Medical Engineering & Cardiology, Research Institute Chest Diseases & Cancer, Associate Professor, 抗酸菌病研究所, 助教授 (90101138)
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| Co-Investigator(Kenkyū-buntansha) |
SEKINO Yoshihito Dept. of Thoracic Cardiovascular Surgery, School of Medicine, Associate, 医学部附属病院, 助手 (30206635)
SUZUKI Yasuyuki Dept. of Thoracic Cardiovascular Surgery, School of Medicine, Associate Professo, 医学部, 助教授 (50004924)
MOHRI Hitoshi Dept. of Thoracic Cardiovascular Surgery, School of Medicine, Professor, 医学部, 教授 (60108503)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Heart Transplantation / Ventricular Assist Device / Total Artificial Heart / Bridge Use / Renal Sympathetic Nerve Activity / Automatic Control System for the Artificial Heart |
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| Research Abstract |
We have been engaged in the development and evaluation of clinical ventricular assist device including micro sensors and optimal automatic drive system for bridge use of heart transplantation. Our sac-type air driven VAD was composed of sac, inflow and outflow cannulae and valve-built-in connector which connects sac and cannula. So we can always develop, improve and exchange any parts independently once some disadvantageous episode happens. Recently, we have been evaluating silatic ball valve for VAD in the chronic animal experiments for 2-3 month and in the mock circulation for over 6 month showing any thrombus formation and any breakage of entire VAD. The flow behavior within our different several types of ventricular assist devices (VADs) had been analyzed with the numerical method based on the quantitative flow visualization technique.
In the in vitro and chronic animal experiments for more than a week, reliable stability and sensitively without any thrombus formation on the blood c
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ontacting surface of the sensors were recognized. After chronic experiments, the sensors were recognized. After chronic experiments, the sensors were reevaluated in the mock circulatory system as compare to reference value. The relationship between the output of the micro-sensors and the reference value were linear and correlated well.
As an automatic control system, a new hemodynamic measurement system has been developed using micro pressure sensors on the wall of both inflow and outflow cannulae to have an adaptive controller of VAD system. With this automatic control system, we newly designed the wean-off method without any volume administration and any cease of VAD drive by changing the drive phase from diastole to systole automatically which resulted in increase of LV outflow impedance. This new method was evaluated in the 7 animal experiments to obtain a LV pressure-volume loop by pressure sensor and conductance catheter in the LV cavity which revealed the usefulness to estimate the cardiac function during bridge used VAD pumping.
To determine the effect of Left Ventricular Assist Device(LAVD) pumping on sympathetic nerve activity, Renal Sympathetic Nerve Activity(RSNA) was detected in acute animal experiments.
During LVAD pumping, RSNA decreased in parallel to the increase in aortic pressure and pulmonary artery flow and decrease in left atrial pressure. These data suggest that LVAD has an effect on the sympathetic nerve system by increase or decrease in tone which mediated by the aortic and cardiopulmonary baroreflex system.
We conclude that our VAD system may offer complete cardiac function for replacing a failing heart until a donor heart can be used as a VAD or a total artificial heart. Less
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Research Products
(8 results)
