If symptoms of atherosclerosis are severe or if a life-threatening blockage is present, aggressive measures may be taken to open up clogged vessels. In addition to angioplasty and coronary artery bypass graft (CABG) surgery, endarterectomy may be performed or thrombolytic therapy given. In endarterectomy, plaques are surgically removed from the walls of the affected artery using a scalpel. Thrombolytic therapy attempts to break up the clot by inserting a clot-dissolving drug into the artery at the point where it is blocked.