Types of stent

In any heart surgery stent is not directly inserted in open condition.they inserted in crimped condition. Once stent is reached at intended location it is expanded.depend up on the expanding  mechanisms defined below:

Balloon Expandable Stent
A balloon expandable stent is expanded by a balloon catheter. The diameter of the stent increases as the balloon diameter increases. The stent remains expanded after deflation of the balloon.

Self-expanding Stent
A self-expanding stent’s diameter increases from its pre-deployed size to its post-deployed size in the absence of balloon inflation or other mechanical assistance. The self-expanding quality can result from material properties or geometry or both.

Stent Delivery System
A stent delivery system delivers a stent to a target site and then deploys the stent.
A stent delivery system for a balloon expandable stent consists of a balloon catheter. Self-expanding stent delivery systems may or may not include a balloon.