Sensorless measurement of biological information in a magnetically levitated artificial heart and its application to QOL improvement technology

Abstract

Heart disease is the leading cause of death in men and women around the world and it is a significant problem that requires remedy. Heart failure is where the heart is not pumping blood around the body as effectively as it should. Importantly, heart failure does not mean that the heart has stopped working, but it does require support in order to get it working better. Over the past few decades, there have been many innovations to help address the problems with heart failure, including developing ventricular assist devices (VADs). A VAD is a mechanical pump that is placed inside the body to support heart function and blood flow in heart patients. It works by taking blood from a lower chamber in the heart and pumping it to the body and vital organs, in the same way that a healthy heart would. Dr Wataru Hijikata is an expert in mechanical engineering and technology with a focus on healthcare outcomes. He explains that the first generation of VADs was a pulsatile flow type, but because of the complicated mechanical structure, the size of them was large and they had low durability. He notes that the second generation VAD was a continuous flow type. Because the blood flow was generated by the rotation of an impeller, the mechanical structure was simple and the size was small. However, the bearings to support the rotating impeller led to low durability. 'Third generation VADs are continuous flow types with contactless support of the impeller by magnetic bearing or hydrodynamic bearings,' Hijikata outlines. Owing to the contactless support technology, the durability of VADs has been enhanced and the size of the device is small. 'However, while there has been significant progress over the years, VADs are still far from perfect and there is much room for improvement,' he concludes. With that in mind, a team of researchers based at the Department of Mechanical Engineering in the Tokyo Institute of Technology, Japan, is investigating a means of improving VADs.