Physiological Adaptation of Ventricular Assist Devices
The Zurich Heart project is a multidisciplinary and inter-institutional cooperation between the University of Zurich (UZH), the UniversityHospital Zurich (USZ), the German Heart Institute Berlin and the ETH Zurich aimed at developing new technologies for left ventricular assist devices (LVADs). The Zurich Heart project was accepted as strategic project by Download Hochschulmedizin Zürich in 2012.
Currently, more than 23 million people worldwide suffer from heart failure. Mechanical circulatory support, i.e. an implantable mechanical pump, has proved a viable solution for such patients, especially given the shortage of donor hearts for transplants.
The existing technology is mainly based on turbo-dynamic pump operating principles. One of the problems of current clinical LVADs is that they operate at a constant speed, which is chosen by the physician, without being adapted to the physiological requirements. This lack of adaptation causes various problems, which affect the patient’s heart and circulation. For instance, ventricular suction due to high unloading can lead to myocardial damage. Low unloading can also cause under-perfusion, flow stagnation or even regurgitation into the pump.
In order to solve these issues, our research concentrates on the following areas:
- Physiological control of LVADs
- Suction detection and prevention
- Investigation of pulsatile LVAD operation
- Physiological control under bi-ventricular support
The above video shows a novel versatile hybrid mock circulation (vHMC) based on the hardware-in-the-loop concept. It is divided into a hardware part and a numerical model of the cardiovascular system. The implant is connected to the hydraulic interface and interacts in real time with the mimicked cardiovascular system. The vHMC enables dynamic testing of active implants, such as ventricular assist devices for left- or biventricular support, testing of total artificial hearts or of novel pump concepts. In addition, it supports testing of passive implants, like valves or grafts. Besides characterizing implants, new control approaches like physiological controllers that allow adjusting the pump flow to the perfusion demand of the patient can be tested.