This 3D animation from The Human Atlas explains Angioplasty and Stent porcedures.

The heart is a beating muscle that continually pumps blood to the rest of the body. The coronary arteries supply the heart itself with the necessary oxygen and nutrients it needs to function effectively.

Over time, fatty deposits called plaque can build up inside the arteries, clogging the passages and reducing the flow of blood. If the coronary arteries develop plaque, blood flow to the heart can be compromised.

Balloon angioplasty is a procedure which opens arteries that have become narrowed or clogged from plaque buildup. During this procedure, a small incision is made in the thigh to gain access to the femoral artery. A guide wire is then inserted into the femoral artery and is threaded through the artery to the site of the blockage.

A catheter that is attached to a deflated balloon moves along the guide wire to the site of the blockage. When the balloon is inflated, it compresses the plaque against the arterial wall enlarging the opening of the artery. This enables blood to move normally through the artery.

Oftentimes during angioplasty, a stent is inserted at the site of the blockage to help the artery from reclosing. A stent is a wire mesh tube placed around the deflated balloon catheter. When the catheter is guided to the blockage site and is inflated, the stent expands and adheres to the artery wall. The catheter and guide wire are then removed and the stent remains in place.

Both angioplasty and angioplasty with stenting may need to repeated if the plaque buildup returns.