Intravascular ultrasound (IVUS) or intravascular echocardiography is a combination of echocardiography and a procedure called cardiac catheterization. IVUS uses sound waves to produce an image of the coronary arteries and to see their condition. The sound waves travel through a tube called a catheter. The catheter is threaded through an artery and into your heart. This test lets physicians look at your blood vessels from the inside out. IVUS images highlight the artery walls and can show if there are cholesterol and fat deposits (plaques).
IVUS is rarely done alone or as a strictly diagnostic procedure. It is usually done at the same time that a percutaneous coronary intervention, such as angioplasty, is being performed.
IVUS uses high-frequency sound waves (also called ultrasound) that can provide a moving picture of your heart. The pictures come from inside the heart rather than through the chest wall. The sound waves are sent with a device called a transducer. The transducer is attached to the end of a catheter, which is threaded through an artery and into your heart. The sound waves bounce off of the walls of the artery and return to the transducer as echoes. The echoes are converted into images on a video monitor to produce a picture of your coronary arteries and other vessels in your body for your physician to see.
In the catheterization laboratory (also called the cath lab), you will see video monitors, heart monitors, and blood pressure machines. You will lie on an examination table, which is usually near an x-ray camera.
Electrodes will be placed on your chest. These electrodes have wires called leads, which hook up to an electrocardiogram machine. This machine will monitor your heart rhythm during the test. To prevent infection, you will be shaved and cleansed around the area of your groin or arm where the catheter will be inserted.
A needle with a tube connected to it will be put in your arm. This is called an intravenous line or IV. You will get a mild sedative through the IV to relax you throughout the test.
You will be given an anesthetic medicine with a needle to numb the area around where the catheter will be inserted. Next, a small incision will be made in the skin allowing your physician to put the catheter into the artery or vein in your groin or arm. You should not feel pain during this part of the test.
The catheter is gently threaded through the artery and into your heart. On the end of the catheter is the transducer, which takes pictures of your heart. Physicians can move the catheter to get pictures of the inside of your heart from different angles.
After enough pictures have been taken, the catheter and IV line will be removed and you will be disconnected from the electrocardiogram machine. After the test, the catheter is removed. A bandage is placed on the area. You will usually be asked to lie flat on your back with pressure on your groin area for a few hours after the test to prevent bleeding.
If IVUS was done during cardiac catheterization, you will normally stay in the hospital for about 3 to 6 hours. If IVUS was done during angioplasty, you may need to stay in the hospital for 12 to 24 hours.