A completely implantable left- and biventricular cardiac assist system
Cardiovascular failure is the most frequent death cause in Germany. In Bavaria, about 60.000 annually die of cardiovascular diseases, corresponding to approx. 50% of all deaths. A possible treatment is the implantation of ventricular assist devices. Such "artificial hearts " do not entirely substitute the natural organ. Rather it is enough to support the left ventricle, which pumps the fresh, oxygen-enriched blood into the systemic cycle.
The draft and the integration of a left ventricular assist system (LVAS) is a task in which primarily fluid mechanical, mechanical, and energy-technical problems must be solved. Blood pumping should be done as carefully as possible to avoid hemolysis and thromboembolism.
The DLR-Heart is designed as a completely implantable assist device (VAD). For left ventricular assistance, it is connected to the left heart chamber and pumps blood back to the aorta using high pressure. For bi-ventricular assistance, each chamber of the device is connected to one ventricle of the native heart. The DLR heart works on the pumping principle of simultaneous suction and forward pumping with the aid of two chambers located on top of each other. This arrangement makes it possible for the unit to intake blood and pump it out simultaneously as one chamber is compressed and the other concurrently released. The two chambers lie very close together. Only if one chamber is compressed, the other can open. This allows for an extremely flat construction. Due to a special designed drive unit and flow-optimized pumping chambers, the energy consumption of the implantable device could be reduced to less then 6 Watt. For transcutaneous energy and data transfer, a wireless transfer system was developed. This system is able to transmit up to 50 Watt to a small, implanted energy reservoir. The transmitted energy is automatically adapted to the requirement of the implant as well as to the load of the implanted accumulator. Due to the new concept and the high efficiency, the DLR Assist Device was awarded with the 2003 Innovation Award of the European Society of Artificial Organs (ESAO).
Prof. Dr. med. Armin Welz, Dr. med. Wolfgang SchillerKlinik und Poliklinik für Herzchirurgie, Rheinische Friedrich-Wilhelms-Universität, Bonn
Prof. Dr.-Ing. Dieter LiepschLeiter Labor für Fluidmechanik, Fachhochschule München, Technische Universität, München, Institut für Biotechnik