How Many Types of Cardiac Catheterization Are There?

During a heart catheterization, doctors insert the tube into a blood vessel. There are two types of cardiac catheterization, left and right heart catheterization.

You may not have had a cardiac catheterization, but you probably know someone who has. Each year in the United States, around 1 million people have cardiac catheterizations. People also refer to these procedures as cardiac caths or heart caths. 

You may be familiar with catheters that drain the bladder. A catheter is any flexible tube with a medical purpose. In cardiac caths, doctors place a catheter in the heart. There are two main types of cardiac catheterizations: left and right, depending upon whether the doctor enters the right or the left side of the heart. These two procedures are similar but have significant differences.

During a heart catheterization, doctors insert the tube into a blood vessel. They thread it through the blood vessel until it enters the heart. Once the catheter is in place, doctors use different techniques to tell how well the heart is working. They can also do some repairs.

Your doctor may suggest that you have a cardiac cath based on test results. Your stress test, electrocardiogram, or other diagnostic tests may indicate a problem. You may need a cardiac cath if you have chest pain (angina), shortness of breath, extreme fatigue, or dizziness. Your doctor may suggest one if you have a known heart condition, including:

• Clogged arteries
• Enlarged heart
• Heart defects that are congenital (existing at birth)
• Heart valve disease
• Heart failure from a weakened heart
• Heart transplant rejection

You can think of the heart as two pumps combined to form one organ. The right side of the heart takes in oxygen-poor blood and pumps it to the lungs to receive oxygen. The left side of the heart takes in the oxygenated blood from the lungs and pumps it to the rest of the body. What we call a heartbeat is the heart contracting to push the blood along. Although the two sides have separate purposes, they contract at the same time. 

Because the left and right sides of the heart are separate pumps, a wall of muscle divides them. This barrier makes it difficult to check both sides of the heart at once. Usually, doctors check the left side of the heart during a left heart cath and the right side during a right heart cath. Occasionally doctors doing a right heart cath may puncture the muscular wall to access the left side.

Left and right catheterizations have these similarities and differences:

• In a left heart cath, the catheter is placed in an artery. In a right heart cath, it's placed in a vein.
• In a right heart cath, the catheter is tipped with a small balloon. Blood flowing through the vein carries it to the heart. This isn't possible in a left heart cath because arterial blood flows away from the heart. 
• Both are invasive procedures, but medical experts consider them safe.
• You'll get a local anesthetic for the entry site in both procedures.
• Both types usually take around 45 minutes. They can take longer if doctors add other procedures. 

Knowing the anatomy of the heart can help you understand heart catheterizations. Oxygenated blood flows through the left side of the heart in this order:

• Blood flows into the left atrium from the lungs.
• It passes through the mitral valve into the left ventricle.
• The left ventricle pumps it through the aortic valve to the main artery, the aorta.
• It flows to the rest of the body. 

Left heart catheterizations have several purposes. Doctors perform these to check the function of the left ventricle, the mitral valve, and the aortic valve. They can check the pressure in different places. They can measure the resistance that the blood must overcome to flow through the heart. 

The most frequent use of a left heart catheterization is to check for clogged arteries, a sign of coronary heart disease. Doctors often inject dye to get a better look using an angiogram procedure. Any blockages found can be treated with:

• Medical management
• Percutaneous coronary intervention (PCI), which opens the arteries with stenting or other methods
• Heart surgery

Sometimes doctors can put in stents or use other forms of PCI during the cardiac cath procedure. 

Blood coming into the right side of the heart follows this path:

• It enters the right atrium through the two largest veins. 
• It passes through the mitral valve into the right ventricle.
• It leaves the heart through the pulmonary arteries and goes to the lungs to get oxygen.

Doctors use right heart catheterization to check the pressure in the heart's two right chambers and the pulmonary arteries. One common use of a right heart catheterization is to check for pulmonary hypertension. 

Pulmonary hypertension is high blood pressure in the arteries that take blood to the lungs. Pressure in this area is ordinarily low because the blood does not have far to travel. When it is high, blood flow to the lungs decreases, and the blood may not get enough oxygen. Pulmonary hypertension is a severe condition that can lead to heart failure.

The results of right heart catheterization can help doctors diagnose and treat several serious heart conditions. It can help them decide whether a person needs a heart transplant.    

Another way of classifying cardiac catheterizations is by point of entry. Doctors can use blood vessels in the groin, arm, wrist, or neck. 

Left cardiac catheterizations have traditionally used the femoral artery in the groin. The term for this method is transfemoral access. In the late 1980s, some doctors began using the radial artery in the arm, entering at the wrist or elbow. This is called transradial access. Using the arm reduces discomfort and can shorten hospital stays. 

If you don't have enough blood flow in your arms, doctors won't be able to use your arm for your heart cath. But if they can, your recovery time should be shorter. Because the femoral artery is so large, if used for a heart cath, the person must lie still for at least 5 hours. Otherwise, there is a risk of bleeding. The radial artery is smaller. If it is used, the person can usually walk soon after the procedure and go home the same day. 

One meta-analysis of 48 studies found that using the arm reduced complications. However, it also increased the chances that the procedure would fail.

Doctors use the arm, neck, or leg for access during right heart catheterization. Each point of access has advantages and disadvantages.