Cardiac catheterization (KATH-eh-ter-ih-ZA-shun) is a medical procedure used to diagnose and treat some heart conditions.
A long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck and threaded to your heart. Through the catheter, your doctor can do diagnostic tests and treatments on your heart.
For example, your doctor may put a special type of dye in the catheter. The dye will flow through your bloodstream to your heart. Then, your doctor will take x-ray pictures of your heart. The dye will make your coronary (heart) arteries visible on the pictures. This test is called coronary angiography (an-jee-OG-rah-fee).
The dye can show whether a waxy substance called plaque (plak) has built up inside your coronary arteries. Plaque can narrow or block the arteries and restrict blood flow to your heart.
The buildup of plaque in the coronary arteries is called coronary heart disease (CHD) or coronary artery disease.
Doctors also can use ultrasound during cardiac catheterization to see blockages in the coronary arteries. Ultrasound uses sound waves to create detailed pictures of the heart's blood vessels.
Doctors may take samples of blood and heart muscle during cardiac catheterization or do minor heart surgery.
Cardiologists (heart specialists) usually do cardiac catheterization in a hospital. You're awake during the procedure, and it causes little or no pain. However, you may feel some soreness in the blood vessel where the catheter was inserted.
Cardiac catheterization rarely causes serious complications.
Doctors may recommend cardiac catheterization for various reasons. The most common reason is to evaluate chest pain.
Chest pain might be a symptom of coronary heart disease (CHD). Cardiac catheterization can show whether plaque is narrowing or blocking your coronary arteries.
Doctors also can treat CHD during cardiac catheterization using a procedure called percutaneous coronary intervention (PCI), also known as coronary angioplasty.
During PCI, a catheter with a balloon at its tip is threaded to the blocked coronary artery. Once in place, the balloon is inflated, pushing the plaque against the artery wall. This creates a wider path for blood to flow to the heart.
Sometimes a stent is placed in the artery during PCI. A stent is a small mesh tube that supports the inner artery wall.
Most people who have heart attacks have narrow or blocked coronary arteries. Thus, cardiac catheterization might be used as an emergency procedure to treat a heart attack. When used with PCI, the procedure allows your doctor to open up blocked arteries and prevent further heart damage.
Cardiac catheterization also can help your doctor figure out the best treatment plan for you if:
- You recently recovered from a heart attack, but are having chest pain
- You had a heart attack that caused major heart damage
- You had an EKG (electrocardiogram), stress test, or other test with results that suggested heart disease
Cardiac catheterization also might be used if your doctor thinks you have a heart defect or if you're about to have heart surgery. The procedure shows the overall shape of your heart and the four large spaces (heart chambers) inside it. This inside view of the heart will show certain heart defects and help your doctor plan your heart surgery.
Sometimes doctors use cardiac catheterization to see how well the heart valves work. Valves control blood flow in your heart. They open and shut to allow blood to flow between your heart chambers and into your arteries.
Your doctor can use cardiac catheterization to measure blood flow and oxygen levels in different parts of your heart. He or she also can check how well a man-made heart valve is working and how well your heart is pumping blood.
If your doctor thinks you have a heart infection or tumor, he or she may take samples of your heart muscle through the catheter. With the help of cardiac catheterization, doctors can even do minor heart surgery, such as repair certain heart defects.
Before having cardiac catheterization, discuss with your doctor:
- How to prepare for the procedure
- Any medicines you're taking, and whether you should stop taking them before the procedure
- Whether you have any conditions (such as diabetes or kidney disease) that may require taking extra steps during or after the procedure to avoid problems
Your doctor will let you know whether you need to arrange for a ride home after the procedure.
Cardiac catheterization is done in a hospital. During the procedure, you'll be kept on your back and awake. This allows you to follow your doctor's instructions during the procedure. You'll be given medicine to help you relax, which might make you sleepy.
Your doctor will numb the area on the arm, groin (upper thigh), or neck where the catheter will enter your blood vessel. Then, a needle will be used to make a small hole in the blood vessel. Your doctor will put a tapered tube called a sheath through the hole.
Next, your doctor will put a thin, flexible guide wire through the sheath and into your blood vessel. He or she will thread the wire through your blood vessel to your heart.
Your doctor will use the guide wire to correctly place the catheter. He or she will put the catheter through the sheath and slide it over the guide wire and into the coronary arteries.
Special x-ray movies will be taken of the guide wire and the catheter as they're moved into the heart. The movies will help your doctor see where to put the tip of the catheter.
When the catheter reaches the right spot, your doctor will use it to do tests or treatments on your heart. For example, your doctor may perform a percutaneous coronary intervention (PCI), also known as coronary angioplasty, and stenting.
During the procedure, your doctor may put a special type of dye in the catheter. The dye will flow through your bloodstream to your heart. Then, your doctor will take x-ray pictures of your heart. The dye will make your coronary (heart) arteries visible on the pictures. This test is called coronary angiography.
Coronary angiography can show how well the heart's lower chambers, called the ventricles (VEN-trih-kuls), are pumping blood.
When the catheter is inside your heart, your doctor may use it to take blood and tissue samples or do minor heart surgery.
To get a more detailed view of a blocked coronary artery, your doctor may do intracoronary ultrasound. For this test, your doctor will thread a tiny ultrasound device through the catheter and into the artery. This device gives off sound waves that bounce off the artery wall (and its blockage). The sound waves create a picture of the inside of the artery.
If the angiogram or intracoronary ultrasound shows blockages in the coronary arteries, your doctor may use PCI to treat the blocked arteries.
After your doctor does all of the needed tests or treatments, he or she will pull back the catheter and take it out along with the sheath. The opening left in the blood vessel will be closed up and bandaged.
A small weight might be put on top of the bandage for a few hours to apply more pressure. This will help prevent major bleeding from the site.
After cardiac catheterization, you will be moved to a special care area. You will rest there for several hours or overnight. During that time, you'll have to limit your movement to avoid bleeding from the site where the catheter was inserted.
While you recover in this area, nurses will check your heart rate and blood pressure regularly. They also will check for bleeding from the catheter insertion site.
A small bruise might form at the catheter insertion site, and the area may feel sore or tender for about a week. Let your doctor know if you have problems such as:
- A constant or large amount of bleeding at the insertion site that can't be stopped with a small bandage
- Unusual pain, swelling, redness, or other signs of infection at or near the insertion site
Talk to your doctor about whether you should avoid certain activities, such as heavy lifting, for a short time after the procedure.
Cardiac catheterization is a common medical procedure. It rarely causes serious problems. However, complications can include:
- Bleeding, infection, and pain at the catheter insertion site.
- Damage to blood vessels. Rarely, the catheter may scrape or poke a hole in a blood vessel as it's threaded to the heart.
- An allergic reaction to the dye that's used during coronary angiography.
Other, less common complications include:
- Arrhythmias (irregular heartbeats). These irregular heartbeats often go away on their own. However, your doctor may recommend treatment if they persist.
- Kidney damage caused by the dye used during coronary angiography.
- Blood clots that can trigger a stroke, heart attack, or other serious problems.
- Low blood pressure.
- A buildup of blood or fluid in the sac that surrounds the heart. This fluid can prevent the heart from beating properly.
As with any procedure involving the heart, complications sometimes can be fatal. However, this is rare with cardiac catheterization.
The risks of cardiac catheterization are higher in people who are older and in those who have certain diseases or conditions (such as chronic kidney disease and diabetes).
The National Heart, Lung, and Blood Institute (NHLBI) leads or sponsors many studies aimed at preventing, diagnosing, and treating heart, lung, blood, and sleep disorders.