An aortic cannula comprises a main body portion and a distal end portion. A lumen extends through the main body portion and the distal end portion to allow fluid communication between the main body portion and the distal end portion. The distal end portion has an inner wall and an outer wall. There is a passageway disposed between the inner wall and the outer wall of the distal end portion. The passageway has an inlet and an outlet, and the passageway is fluid communication with a surrounding environment. There may be a stop ring disposed about the distal end portion between the inlet of the passageway and the outlet of the passageway.
