Third‐generation Blood Pumps With Mechanical Noncontact Magnetic Bearings

Abstract

This article reviews third-generation blood pumps, focusing on the magnetic-levitation (maglev) system. The maglev system can be categorized into three types: (i) external motor-driven system, (ii) direct-drive motor-driven system, and (iii) self-bearing or bearingless motor system. In the external motor-driven system, Terumo (Ann Arbor, MI, U.S.A.) DuraHeart is an example where the impeller is levitated in the axial or z-direction. The disadvantage of this system is the mechanical wear in the mechanical bearings of the external motor. In the second system, the impeller is made into the rotor of the motor, and the magnetic flux, through the external stator, rotates the impeller, while the impeller levitation is maintained through another electromagnetic system. The Berlin Heart (Berlin, Germany) INCOR is the best example of this principle where one-axis control combination with hydrodynamic force achieves high performance. In the third system, the stator core is shared by the levitation and drive coil to make it as if the bearing does not exist. Levitronix CentriMag (Zürich, Switzerland), which appeared recently, employs this concept to achieve stable and safe operation of the extracorporeal system that can last for a duration of 14 days. Experimental systems including HeartMate III (Thoratec, Woburn, MA, U.S.A.), HeartQuest (WorldHeart, Ottawa, ON, Canada), MagneVAD (Gold Medical Technologies, Valhalla, NY, U.S.A.), MiTiHeart (MiTi Heart, Albany, NY, U.S.A.), Ibaraki University's Heart (Hitachi, Japan) and Tokyo Medical and Dental University/Tokyo Institute of Technology's disposable and implantable maglev blood pumps are also reviewed. In reference to second-generation blood pumps, such as the Jarvik 2000 (Jarvik Heart, New York, NY, U.S.A.), which is showing remarkable achievement, a question is raised whether a complicated system such as the maglev system is really needed. We should pay careful attention to future clinical outcomes of the ongoing clinical trials of the second-generation devices before making any further remarks. What is best for patients is the best for everyone. We should not waste any efforts unless they are actually needed to improve the quality of life of heart-failure patients.

Devices in Heart Failure

“…71- 73 The other technologies in development have modified the design of the suspension system and testing, a combination of magnetic and hydraulic bearings, and more durable as well as stable sensors and instruments. 74 Total artificial hearts (TAH) are a developing option for those requiring biventricular support. One such device is the CardioWest TAH (TAH-t; SynCardia, Inc, Tucson, AZ, USA).…”

Magnetic levitation performance of miniaturized magnetically levitated motor with 5-DOF active control

“…and high share stress at mechanically contacting region. In contrast, due to removing the need for contact bearing, magnetically levitated rotary VADs have significant advantages such as long life expectancy, low thrombosis, less hemolysis and high-speed operation compare to conventional blood pumps with mechanical bearings and seals contacting with the blood (Hoshi, et al, 2006, Timms, et al, 2011, Yumoto, et al, 2009. In this study, a tiny double-stator axial gap type magnetically levitated motor that can control 5 degrees of freedom (5-DOF) of rotor impeller postures have been developed for use in pediatric continuous flow rotary VAD.…”

Study on Driving Motor for Magnetic Levitated Artificial Heart Pump

“…Performance and the size of a driven motor directly determines the performance and the size of a heart pump. Direct-drive pump has low power consumption and high energy conversion efficiency, so the application is mature and widely [1]. In terms of the choice of drive motor, DC motor and permanent magnet synchronous motor are used widely in domestic products.…”