A cardioplegia occluder and methods of using the device during cardiac surgery are disclosed. The system typically includes a substantially rigid cannula with an occluder mounted on the distal region of the cannula that expands upon activation to occlude the aorta downstream of an infusion port which delivers cardioplegia solution to arrest the heart. Systems including cutting blades, blade guards, flanges, radiopaque markers and occluder aligners are also disclosed. In use, the distal end of the cannula is inserted through an incision into the aorta, the occluder is expanded and cardioplegia solution is infused upstream of the aorta to arrest the heart. The infusion port can alternately be used to aspirate cardioplegia or embolic debris or other unwanted material from the aorta.