Preclinical Studies on the Use of a Pulsatile Paracorporeal Assist Devices

An assistance artificial heart was fabricated with blood compatible polyurethane　having 3 different sizes and was evaluated by a series of preclinical experiment in　calves. The following results were obtained.

1) The artificial heart was constructed in 3 sizes of 60, 80 and 100 cc in capacity　and is activated by a pneumatic heart driver console.

2) The mock circulation revealed that this assistance heart has ejection fraction of　80-95%.

3) Safe use of assistance heart has been confirmed by implantation in 18 calves　with intact or failured hearts over a period of 3 months.

4) Weaning could be performed in cases where myocardial necrosis of the left　ventricle is induced less than 35% utilizing myocardial injection of 5N-NaOH. However　pump dependency develops for a necrosis exceeding 35 %.

5) Thus we concluded that this system can be safely employed for a one month　cardiac assistance clinically and at most for a 3 months support in pump dependent　cases.

6) The technique was developed to make the instant shift possible within a few　minutes from the conventional non-pulsatile bypass assistance to the assistance heart.