Our artificial heart research is to develop a totally implantable total artificial heart (TAH). To meet the purpose, we invented a small-size continuous-flow blood pump with high performance, high durability and good blood compatibility named the helical flow pump.  Using helical flow pumps, the helical flow total artificial heart (HFTAH) is under the development. The HFTAH is designed to be small enough to be implanted in the body of small stature like Japanese women, and is expected to be durable for more than 10 years with the hydrodynamic levitation impeller. This TAH is designed to generate quasi-pulsatile flow by changing motor speed periodically. To find out the weak points of the device in vivo and to develop a physiological flow control method for this device, the first version model of the HFTAH has been tested with animal experiments. At the present time, 100 days of survival was obtained with no systemic administration of anticoagulant and anti-platelet.

How to control the output of TAH is another big subject. We have developed our original control method, named 1/R control, in which cardiac output is controlled by the cardiovascular center through the feedback mechanism using changes in total peripheral resistance and arterial pressure. At the present time, 1/R control is the only reported method to achieve a physiological control of a TAH logically. With 1/R control, the particular problems of TAH such as venous hypertension, slight anemia, low thyroid hormone level, and so on, were not observed and the output was changed in accordance with a metabolic condition of the animal. The 1/R control equation was simplified and installed in the HFTAH and pathphysiological study is being performed.

Helical flow total artificial heart

Helical flow pump

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