Doctors insert a balloon-tipped catheter into a large artery (sometimes the femoral artery, but the radial artery in the wrist is now used most commonly) and thread the catheter through the connecting arteries and the aorta to the narrowed or blocked coronary artery. Then doctors inflate the balloon to force the atheroma against the arterial wall and thus open the artery. Usually, a collapsed tube made of wire mesh (a stent) is placed over the deflated balloon at the catheter’s tip and inserted with the catheter. When the catheter reaches the atheroma, the balloon is inflated, opening up the stent. Then the balloon-tipped catheter is removed, and the stent is left in place to help keep the artery open.