A stent is a wire mesh tube intended to prop open an artery. When made from stainless steel or nickel-titanium (nitinol), stents are intended to be permanent. More recent stents are made of polymers designed to dissolve over a period of months.
Fatty deposits called plaque can build up in an artery and reduce the flow of blood. When this happens in a coronary artery – one that directs blood from the heart – chest pain or angina can result. A complete blockages of blood flow to a part of the heart muscle results in a heart attack. Stents help keep coronary arteries open, reducing the chance of a heart attack.
To open a narrowed artery, percutaneous coronary intervention or angioplasty may be used. A balloon-tipped catheter is inserted into an artery and moved to the point of blockage. The balloon is inflated, compressing the plaque to restore flow. When the opening in the vessel has been widened, the balloon is deflated and the catheter withdrawn.
During manufacturing, stents are collapsed over a balloon catheter. In a placement procedure, the balloon catheter-stent is moved into the area of blockage. When the balloon is inflated, the stent expands and stays in place when the ballon is deflated and withdrawn, providing a scaffold to hold the artery open.