A stent is a small, tube-like device used in medicine to keep blood vessels or other passages open. It is often made of metal or plastic and is inserted into narrowed or blocked areas, such as arteries, to improve blood flow. This procedure is commonly performed during a treatment called angioplasty, where a balloon is used to widen the blocked area before placing the stent. Stents are crucial in treating conditions like coronary artery disease, where the heart's arteries become narrowed due to plaque buildup. By keeping these arteries open, stents help reduce the risk of heart attacks and improve overall heart health, allowing patients to lead more active lives.