Coronary arteries are the blood vessels that supply oxygen-rich blood to the heart muscle. The coronary arteries can get blocked by the buildup of plaque. Plaque is made up of extra cholesterol, calcium, and other substances that float in blood. Over time, plaque can build up on the inside walls of the coronary arteries and block the blood flow. A procedure called angioplasty can open up a blocked artery.

An angioplasty is done using a thin, soft tube called a catheter. The catheter is guided into the blood vessels of the heart. First, your doctor inserts the catheter into a blood vessel in the groin, arm, or wrist. A very thin guide wire is inside the catheter. Your doctor carefully guides the catheter through blood vessels into the blocked portion of the coronary artery. Your doctor watches the movement of the catheter in the blood vessels on an X-ray screen.

After the catheter reaches the blocked artery, your doctor will move the guide wire farther into the blocked portion. A small balloon is slid along the guide wire into the blocked artery. In most cases, a small, expandable wire-mesh stent is placed in the artery with the balloon.

The small balloon is inflated. The balloon may stay inflated for a short time. The pressure from the inflated balloon presses the plaque against the wall of the artery, creating more room for blood to flow. The inflated balloon also expands the wire-mesh stent.

Next, the balloon is deflated. But the stent stays expanded. The stent presses against the walls of the artery and keeps the artery open. Your doctor removes the balloon, guide wire, and catheter. The stent remains in the blood vessel, allowing the blood to flow normally again.

After an angioplasty, the blocked artery is opened up and oxygen- and nutrient-rich blood flows more normally into the heart muscle.

These X-rays show a blocked coronary artery before and after an angioplasty procedure. Before angioplasty, the blood flow is blocked by a narrowed artery. After the angioplasty, blood is flowing better through the newly opened artery. These X-rays are from an angiogram. An angiogram is a test that uses a special dye and camera to take X-ray pictures of the blood flow in an artery.