Centrifugal blood pumps have been used extensively for short term circulatory assistance and perfusion pumps. Their utility for long term ventricular assistance is limited by thrombus formation at the shaft seal. Abiomed proposes to develop a magnetically suspended centrifugal blood pump which will have no shaft seal, suitable for long term circulatory support in either an implanted or extracorporeal configuration. We will utilize an attraction type magnetic bearing with a radially passive, axially active geometry. There will be a simple fluid flow path around a toroidal rotor which is the only moving solid element. The resulting pump can be small, light, simple, and very reliable, while not being limited to short term use by the shaft seal of presently used centrifugal infusion pumps. This device will be more compact and inherently simpler than valved pulsatile Ventricular Assist Devices. With only one moving part, needing no pulsatile or nonpulsatile modes, such a pump with low hemolysis and thrombogenesis levels will be an extremely reliable and widely applicable form of cardiac support.
