Axial flow pump with multi-grooved rotor

An axial-flow blood pump includes a housing having an inlet and an outlet opposite therefrom. An impeller located within the housing is suspended during operation by magnetic forces between magnets or magnetized regions of the impeller and a motor stator surrounding the housing, and hydrodynamic thrust forces generated by a flow of blood between the 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 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 the housing in a coaxial direction of the housing.