Heart valve surgery. Artificial heart valve being stitched ready to be pulled into position in the heart during heart valve replacement surgery. This is heartport surgery, a type of keyhole (minimally-invasive) surgery used as an alternative to open heart surgery (where the chest is opened by sawing through the breast bone). The small hole (port) is seen at lower centre. The advantages of heartport surgery are improved patient comfort and a reduced period of convalescence. Heart valves prevent blood from flowing back into the heart chamber from which it has just been pumped. Valve failure may be life- threatening.