Artherectomy is a procedure for opening a coronary artery blocked by plaque, the buildup of cholesterol and other fatty substances in the inner lining of the artery. A catheter is introduced into the body through a blood vessel in the leg or arm and is threaded through the blood vessels to the blocked artery. The tip of the catheter is a high speed rotating device which grinds the plaque up into minute particles. Balloon angioplasty may then be used to help re-open the narrowed area of the artery.