USING HYBRID MAGNETIC BEARINGS TO COMPLETELY SUSPEND THE IMPELLER OF A VENTRICULAR ASSIST DEVICE

Clinically available blood pumps and those under development suffer fr om poor mechanical reliability and poor biocompatibility related to an atomic fit, hemolysis, and thrombosis. To alleviate these problems con currently in a long-term device is a substantial challenge. Based on t esting the performance of a prototype, and on our judgment of desired characteristics, we have configured an innovative ventricular assist d evice, the CFVAD4, for long-term use. The design process and its outco me, the CFVAD4 system configuration, is described. To provide unpreced ented reliability and biocompatibility, magnetic bearings completely s uspend the rotating pump impeller. The CFVAD4 uses a combination of pa ssive (permanent) and active (electric) magnetic bearings, a mixed flo w impeller, and a slotless 3-phase brushless DC motor. These component s are shaped, oriented, and integrated to provide a compact, implantab le, pancake-shaped unit for placement in the left upper abdominal quad rant of adult humans.