Until recently, angiography was the best method for assessing blood vessel function. This procedure involves injecting a contrast agent into the blood and using an X-ray to determine if a blood vessel is working properly.
Improvements in blood vessel evaluation have resulted in the development of intravascular ultrasound, or IVUS. This procedure provides more detailed information about the vessels and their function, improving patient diagnosis and treatment.
IVUS uses sound waves to map the inside of your arteries. Using a small ultrasound device mounted on a catheter, your doctor can view the inside of the arteries as the catheter passes through them. Other names for an intravascular ultrasound include:
- ultrasound-coronary artery
- endovascular ultrasound
- intravascular echocardiography
An intravascular ultrasound is typically ordered along with tests to evaluate your heart function and treat certain cardiac conditions. Specifically, IVUS is ordered to:
- ensure that a stent (a tube used to improve blood flow) was properly placed during angioplasty (a procedure to widen a narrowed blood vessel)
- view the aorta and coronary arteries to monitor the build-up of plaque
- identify vessels involved in an aortic dissection (when blood leaks into the walls of your aorta)
The advantage of the intravascular ultrasound test is that it gives your doctor a detailed look inside your blood vessels. Based on the information collected from the test, your doctor can make a quick and accurate diagnosis of your condition.
In most cases, you will be allowed to eat a small meal the night before the test, though you may be required to fast for up to 12 hours.
Depending on your specific health conditions, your doctor may ask that you stop taking certain medications before the test. Your doctor may also prescribe medication to prevent blood clots from forming during the test.
The intravascular ultrasound is typically administered in a hospital.
Before the test, you will be given a sedative medication to help you relax. You will be awake but groggy during the procedure. In addition to the sedative, a local anesthetic will be applied to the area on your groin or arm where the catheter will be inserted.
Typically, the catheter is inserted in the groin through the femoral artery (a large artery in your thigh). The catheter is pushed through the artery until it reaches the heart and the blood vessels being examined.
The ultrasound device on the tip of the catheter uses sound waves to take pictures of the vessels. These images are recorded on a computer. Once the test is completed, the catheter is removed and pressure is placed on the insertion site to prevent bleeding.
After the test, you will need to remain in the hospital under observation. This is to ensure that no bleeding occurs at the insertion site. Patients admitted for IVUS only will need to remain in the hospital for three to six hours for observation. Patients admitted for cardiac catheterization along with IVUS will need to remain in the hospital for 12 to 24 hours.
After you are released from the hospital, you will be given specific care instructions. You should avoid strenuous lifting to prevent bleeding at the catheter insertion site. The site may also be sore and bruised for several days.
Although intravascular ultrasound is a fairly routine test for monitoring cardiac health, it does carry some risks. These include:
- irregular heart rhythms (arrhythmia)
- bleeding at the site where the catheter was inserted
- a blood clot
- an allergic reaction to the anesthesia used during the procedure
- damage to the blood vessel wall
- kidney failure
- a heart attack or stroke (rarely)
Tell your doctor right away if, after the test:
- the catheter insertion site begins to bleed or swell
- you feel pain, numbness, or tingling in your leg or foot
- you have a rash, itching, sweating, or breathing problems
- you have unusual chest pain
- you have speech or balance problems or trouble using your arm or leg
How the results are interpreted depends on what your doctor finds during the test (plaque build-up in your arteries, for example). Based on the doctor’s findings, he or she may order additional tests or begin treatment.