A coronary artery stent is a small, metal mesh device that is placed inside a coronary artery, it acts as a support or scaffold, to keep the vessel open. By keeping the vessel open, the stent helps improve blood flow to the heart muscle and reduce chest pain. Stent procedures are usually used along with balloon angioplasty. In fact, approximately 80% of patients who have balloon angioplasty will have a stent placed in as well.