the doctor will insert a tiny, flexible plastic tube called a catheter through an artery in our groin, leg, or arm. A special dye is injected so blood flow through the arteries is visible on the TV monitors. The doctor moves a balloon catheter, and then a stent, to the site of the blockage. The balloon is inflated and stretched wide against the artery walls, which opens the blockage. Then the balloon is deflated and taken out, leaving the stent in place.