Improvement of durability in the undulation pump total artificial heart

The undulation pump total artificial heart (UPTAH) is a unique implantable total artificial heart using undulation pumps, small size continuous flow displacement-type blood pumps. The principle of undulation pump was proved to work well in 1992. After several improvements and developments, the second model (UPTAH2) could be implanted in the chest of 14 goats weighting 41.3-79.2kg. The longest survival period with UPTAH2 was 10 days limited by the insufficient durability in drive mechanism. To improve the durability, the third model (UPTAH3) was newly designed. The drive mechanisms of UPTAH3 were designed separately for the left and right pumps. That in left pump was designed more durable than that in right pump. The undulation pumps were also redesigned to match these drive mechanisms. Additionally, the new undulation pumps were designed to have a little narrow angle between the inlet and outlet ports to acquire better anatomical fitting. The central connecting part in the disk was designed to be hard using metal core. The completed UPTAH3 was 76 mm in diameter, 79 mm in length, 292 ml in total volume and 620 grams in weight. The atrial cuffs and outflow canulae were redesigned for UPTAH3. The maximum continuous output was 15 L/min. The maximum pump efficiency was about 15%. The maximum total efficiency excluding controller was about 10%. To date, the implantation of UPTAH3 was performed in 8 goats weighting 41.7-49.1kg. The UPTAH3 was driven with pulsatile mode by switching the motor speed making systolic and diastolic phases. The longest survival period with UPTAH3 was prolonged to 46 days without giving any anticoaglant and antiplatlet drug systematically. The cause of termination was the disconnection of cord from the right motor inside the chest. The results showed that the improvement of the durability was effective in the third model.