| Budget Amount *help |
¥27,000,000 (Direct Cost: ¥27,000,000)
Fiscal Year 1985: ¥10,000,000 (Direct Cost: ¥10,000,000)
Fiscal Year 1984: ¥17,000,000 (Direct Cost: ¥17,000,000)
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| Research Abstract |
The overall objective of this research was 1) to perform total heart replacement study in animals using high performance pusher-plate type blood pumps, 2) to evaluate feasibility of temporarily using total artificial heart(TAH) as a bridge to heart transplantation, and 3) to establish basis for future development of permanent-use totally implantable TAH system.
The heart replacement was performed in adult goats with a pair of pusherplate type blood pumps(left stroke volume 65cc, right 50cc). Under gas anesthesia, right 4th intercostal thoracotomy was performed, followed with start-up of CP-bypass. The heart was then removed and inflow and outflow connectors were positioned in the appropriate places. The left pump was first connected and started, then the start-up of the right pump, followed with termination of CP-bypass. Postoperatively, both atrial, and pulmonary and aortic pressures, both pump flows derived from the Hall effect signal were continuously monitored. The blood samples were intermittently taken, and blood gases, lactate level were analyzed to evaluate status of the lungs and peripheral circulation. As a control strategy, both perload and afterload of the TAH were adjusted to yield pump flows above 70 ml/kg/min and also to maintain mixed venous saturation above 65% and blood lactate level to a minimum level. To date, a total of 16 goats were implanted with the pusherplate type TAH; the longest survival time was 48 hours mainly due to poor lung function and also to failure of peripheral circulation. So, the animal was changed to calves which may be able to tolerate long CP-bypass time and larger calf size pumps(left 90cc, right 80cc) were designed and fabricated. The TAH study continues with the calves. As for totally implantable TAH system, motor driven TAH system was designed and its anatomical fit was confirmed in 60kg goat. The system is under bench testing.
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