Angioplasty & stenting

If a blockage of a blood vessel is detected during an angiograpy procedure, this can be treated during same procedure using a number of methods. Angioplasty uses a special catheter with a small deflated balloon at one end. Under x-ray guidance, the catheter is passed to the site of the blocked vessel. The balloon is then inflated to open up the vessel. This pushes the atherosclerotic plaque that is blocking the vessel to the sides of the vessel walls, effectively unblocking the artery. The balloon can then be deflated and the catheter removed. [diagrams of ballon stent, before and after ballooning]

There is usually a good success rate, as defined by the blood vessel remaining patent following angioplasty. This depends on the size and complexity of the stenosis, the skill of the operator and the location of the stenosis. Complications occur in 2-3% of patients, but are usually minor and the same as the risks of angiography.

Sometimes a stent is used after angioplasty to prevent the vessel from narrowing again. A stent is a small metal mesh that is designed to support the vessel walls mechanically. The stent sits on top of a deflated balloon catheter, which is inserted so that the ends of the stent cover the entirety of the stenosis. When the ballon is inflated, the stent expands, supporting the vessel walls. The stent remains in place even after the balloon catheter is removed, and eventually becomes integrated into the vessel wall. The success rate is very high. Complications include those of angiography as well as formation of a clot or scar tissue within the stent. This may require re-stenting later on.

A new type of stent, the drug-eluting stent, has been developed to reduce the risk of scar tissue stenosis within the stent. This is currently only used in heart procedures.