An axial-flow
blood pump for pumping blood includes a substantially cylindrical outer
enclosure. A tubular housing concentric with and located within the outer
enclosure has at one end an inlet and at an opposite end an outlet. A motor
stator is concentric with and located between the outer
enclosure and the tubular housing. An
impeller is concentric with and located within the tubular housing. The
impeller is suspended in operation by a combination of passive magnetic forces between magnets within the
impeller or magnetized regions of the impeller and the motor
stator and hydrodynamic thrust forces generated as blood flows between the tubular housing and a plurality of hydrodynamic
thrust bearing surfaces located on the impeller. A
volute may be in fluid-tight connection with the outlet of the tubular housing for receiving blood in the axial direction and directing blood in a direction normal to the axial direction. The
volute has a flow-improving member extending axially from the
volute and into and coaxially with the tubular housing.