A temporary cardiac-assist device (110) is disclosed. The device (110) includes a pump assembly (118) that is deployed in the ascending aorta (222) or the heart. A torque transmission line (116) couples the pump assembly (118) to an external motor for driving impeller blades within the pump assembly. The pump assembly (118) expands in size at its destination site for operation. In operation, neither the torque transmission line (116) nor elements that, support the impeller blades (570) are under axial forces.