Approximately 70 percent of angioplasty procedures also involve stenting, which is the insertion of a small metal cylinder called a stent into a blood vessel. In this procedure, a collapsed stent is placed over the balloon at the tip of the catheter. When the balloon inflates, the stent pops open and reinforces the artery walls. The balloon and catheter are then withdrawn and the stent remains permanently. In a few weeks, tissue from the artery lining grows over the stent.
There are two types of stents. Bare-metal stents are plain, untreated metal cylinders. Drug-eluting stents (also called drug-coated stents) are coated with medication before they are placed in the artery. This medication helps prevent scarring and lowers the risk for restenosis (re-narrowing of the artery). Drug-eluting stents may present a higher risk for blood clot formation than bare-metal stents.