A stent is a small, coiled wire-mesh tube that can be inserted into a blood vessel and expanded using a small balloon during a procedure called angioplasty. A stent is used to open a narrowed or clotted blood vessel, most often an artery in the heart.

When the balloon inside the stent is inflated, the stent expands and presses against the walls of the artery. This traps any fat and calcium buildup against the walls of the artery, allows blood to flow through the artery, and helps prevent the artery from closing again (restenosis). It can also help prevent small pieces of plaque from breaking off and causing a heart attack.

To insert the stent, a flexible, thin tube (catheter) is passed through an artery in the groin or arm into the narrowed artery. Then the balloon inside the stent is inflated.

Some stents are coated with a medicine to more effectively prevent restenosis.