Ventricular Assist Devices Utilizing Magnetic Bearing Systems

Abstract

This chapter discusses the principles of magnetic bearings, which are key components for third-generation Ventricular Assist Devices (VADs). Furthermore, prototypes of implantable magnetically levitated VADs and disposable VADs for extracorporeal circulation are shown. In the early stages of development of continuous flow VADs, problems with durability, hemolysis, and thrombus formation also occurred. The chapter also discusses the principles, configurations, and prototypes of magnetic bearings for VADs are introduced. In centrifugal-type VADs, a magnetic bearing and a motor are combined in various ways, and the different combinations result in different sizes and control methods. Industrial magnetic bearing systems usually adopt two sets of active radial magnetic bearings and an active thrust magnetic bearing. Some magnetic bearing structures that combine active and passive magnetic bearings have been proposed in order to minimize the number of controlled degrees of freedom and simplify the magnetic bearing system.