Stents are metallic slotted tubes that are placed at the site of a coronary blockage to open up the inside of the artery to allow for increased blood flow through the artery. These metal tubes are crimped onto a balloon. The balloon with the crimped stent on it are then advanced over a wire (like a train on tracks). Once the stent reaches the area of blockage (or stenosis), the balloon is expanded so the stent gets deployed in the artery. In order to be effective, the stent must be fully touching the internal artery wall on all sides. The stent is permanent. It never comes out. Although its metallic, stents don’t set off metal detectors at security screening stations and are safe from MRI after 6-8 weeks of intial implantation.