ADVANCEMENT OF THE UNDULATION PUMP TOTAL ARTIFICIAL HEART(UPTAH)

Abstract

UPTAH is an implantable TAH developing in our laboratory in these 6 years. Many achievements concerning to the hard and software could survive TAH animal for long-term. Mechanism and merits: UPTAH is composed of 2 UPs 2 conversion mechanisms and 2 brushless DC motors, in which the motor revolution converts to the undulation motion of a disc by the conversion mechanism. The disc can squeeze blood from the inlet to the outlet of the pump. UPTAH has the following merits; very compact(76mm in diameter, 78mm in long), arbitrary flow pattern can be produced, the right and left heart can control independently, only one valve in the aortic cannula is required for the safety and no compliance chamber is required. Materials: Pump housing and disc was made of urethane resin. Atrial cuff was made of Gore-Tex sheet. Aortic cannula in which a jellyfish valve was incorporated, was attached Gore-Tex vascular graft. All blood contact surfaces were coated with segmented polyurethane. Measurement and control: Electromagnetic flow probes were installed into aortic and pulmonary artery cannulae to control the pump flow. The right and the left atrial pressure, aortic pressure and pulmonary artery pressure were measured by pressure transducers. The flow patterns, continuous, pulsatile and pulsatile on continuous, could change pulse width modulation(PWM) of the motor current. The basic control method was an automatic left atrial pressure control in which the sucking of the atrial wall and elevation of the left atrial pressure were automatically protected. I / R control which had succeeded to survive pneumatic driven TAH goat for more than 500 days without pathophysiological abnormality, was also applied after several days of the surgical operation. Animal experiments: UPTAH has been implanted into 40 goats' chest cavity weighing between 40 and 79 Kg since 1995. No anticoagulant was used after the surgery in these experiments. Until now, 7 goats survived over 2 weeks and 4 goats survived over one month including 50 days as the longest. And one goat is on going with a very good condition over 35 days