A high efficiency blood pump includes a pump housing (15), wherein the pump housing (15) provides an inlet (20) and outlet (25). The pump includes a motor housing (35), wherein the motor housing (35) contains a motor (40). An impeller (75) is housed in the pump housing (15), wherein the impeller (75) is radially supported by a hydrodynamic bearing providing at least one row of pattern grooves. A diaphragm (60) provided by the pump housing (15) separates the impeller (75) from the motor (40). A magnetic coupling is provided between the motor (40) and the impeller (75), wherein the magnetic coupling causes the impeller (75) to rotate when the motor (40) rotates and provides axial restraint of the impeller (75).
