A flow thru mechanical bearing system can be used in an implantable rotary blood pump that includes a pump housing. An impeller housed in the pump housing can be radially supported by a row of at least three low friction contact points located on an inside bore of the impeller. The impeller may be axially supported by a second mechanical bearing. The second mechanical bearing may provide at least three axial contact points on the top surfaces of the impeller. The impeller is driven by a magnetic coupling which functions mainly to transmit torque to the impeller. Further, in some cases, the magnetic coupling may restrain axial motion of the impeller.
