What is cardiac catheterization?
Cardiac catheterization allows the doctor to assess the pressures within the heart, to evaluate the pumping function of the heart and to obtain a “road map” of the coronary arteries (the vessels that supply the oxygen-rich blood to the heart muscle). A cardiac catheterization may also be called a coronary angiography, angiogram or heart catheterization.
During a cardiac catheterization, your cardiologist will insert a very narrow, soft flexible plastic tube called a catheter, through an artery and/or vein in your groin. The cardiologist will then thread the catheter through your aorta into your heart. Special X-ray equipment is used to watch the arteries and the left ventricle.
Why is catheterization important?
A cardiac catheterization provides more precise information about the presence or absence of blockages in the coronary arteries. It also gives more accurate, detailed information about the heart’s function than any other test allowing your cardiologist to choose the most effective treatment.
How your heart works
Your heart is a muscular, hollow organ that is approximately the size of your closed fist. The heart rests directly under the breastbone and it tilts toward the left side of the chest. The heart has four chambers or compartments. There are two chambers on the left side and two on the right side. The upper chambers on each side are called atriums. These chambers receive and collect blood. The lower chambers are called ventricles. The left ventricle, the heart’s main pumping chamber, is made up of strong muscle and pumps blood to the body. The right ventricle pumps blood to the lungs.
The heart has four valves to control the flow of blood. The blood in your body flows in only one direction. Veins bring the blood back to the right side of the heart where it is pumped into the lungs to pick up oxygen. The oxygen-rich blood flows from the lungs into the left side of the heart before it is pumped back through to the body by the arteries.
The coronary arteries carry oxygen-rich blood to the heart muscle. When blood leaves the left ventricle, it enters the aorta--the body’s main artery. At the beginning of the aorta are the two coronary arteries, one on the left side of the heart and one on the right. The first segment of the left coronary artery is called the left main artery. It branches into two smaller arteries, the left anterior descending and the circumflex artery. The left anterior descending travels down the front of the heart while the circumflex circles around the right side and back of the heart. The coronary arteries penetrate deep into the heart muscle to deliver oxygen-rich blood to the cells.
Heart conditions that cardiac catheterization can diagnose
- Coronary Heart Disease
Inside a normal artery the walls are smooth and flexible, allowing blood to flow through them easily. The inside walls may become plugged with fatty deposits that build up over years. These deposits, known as plaque, can lead to a heart attack or angina (pain or discomfort in the chest, arm or neck). During a cardiac catheterization, dye is injected into the coronary arteries. Pictures are taken that show how severe any blockages may be.
- Defective heart valves
When one or more of the heart’s valves do not work properly, a valve disease is present. For example, a valve may be narrowed or leaky. Most defects are minor and have little effect on the pumping function of the heart. But some defects may worsen over time. A heart catheterization can accurately measure how narrow the valve is, or how much it is leaking.
- Congenial heart defects
Deformities of the heart (such as a hole between the chambers or a narrow valve) that are present at birth are called congenial heart defects. A severe defect can cause the heart to work harder, and might weaken the heart causing other symptoms. A cardiac catheterization can confirm and assess the extent of the problem.
Preparing for catheterization
It is very important that you do not eat or drink anything after midnight the night before the procedure. You may take your usual morning medications with a sip of water before going to the hospital. If you usually take insulin in the morning, check with your doctor for any adjustments in the dose the morning of the procedure. Be sure to bring a list of all the medications you are taking, along with the dosages, and any allergies you may have. If you have ever had an allergic reaction to X-ray, dye, iodine or seafood, be sure to inform your nurse.
Unless you are hospitalized, you will probably be able to go home the day of the procedure. Be sure to arrange to have someone drive you home—you will not be allowed to drive the day of the procedure.
You should come to the catheterization lab at your designated time. Prior to the procedure, your pulse, respiration rate, temperature and blood pressure will be taken. Electrodes will be placed on your chest to monitor your heart rhythm and an intravenous (IV) needle will be inserted into a vein in your arm. This IV allows medications to be injected directly into the vein for sedation during the procedure. Some routine tests will also be performed, including an ECG, blood tests and a chest X-ray. Prior to the procedure, you may also have had some blood tests done at your doctor’s office.
Next, the staff will explain the procedure to you and your family. This is a good time to ask questions and share any concerns you have. You are allowed to have one family member at your bedside. Children under the age of 12 are not allowed in the catheterization lab area. When you are ready, your family will be directed to the waiting area where the cardiologist will talk to them after the procedure. Telephones are available in the recovery area for you and your family to use. (Cellular phones cannot be used anywhere in the hospital because they can cause interference with sensitive electronic equipment.)
Immediately before the procedure, you will need to empty your bladder. You may wear your denture, hearing aids and eyeglasses during the procedure if you wish.
During the procedure
The catheterization is performed in a specially equipped X-ray room. The staff will be wearing surgical hats and masks because it is a sterile procedure. You will be transported to the catheterization lab on a cart and asked to scoot onto the X-ray bed. You will be positioned on the bed and connected to an ECG monitor and automatic blood pressure cuff. You will also have an oxygen monitor placed on your fingertip.
The bed you are in will have a tube above it containing the camera. The room will be equipped with several television screens, allowing the doctor “live” viewing of the pictures. The catheterization lab team includes the doctor, two or three technicians and a nurse. The nurse will give you a sedative through the IV. It will make you feel sleepy and relaxed. After receiving the medication, you may require oxygen from a plastic tube that fits in your nose. Now it is time to begin the catheterization.
First, the groin will be shaved and cleansed with surgical soap and a sterile drape will be placed over your body. The doctor will inject a local anesthetic, which may burn or sting until the site becomes numb.
Next, a small incision will be made and a needle will puncture the artery where the catheter is inserted. The doctor will advance the catheter toward the heart by following its progress on the television screen.
After the catheter is in place, dye is injected into the arteries (also called a coronary angiogram) several times. The camera above you will take moving pictures to record the flow of the dye. These pictures show areas of narrowing or blockages of the arteries and will assess their severity. It is possible to feel a brief warm sensation in the chest from the dye.
Next, the catheter is directed into the left ventricle of the heart where more dye is injected. This is called a left ventriculogram. These injections give a detailed moving picture of the left ventricle during its pumping action. If patients have leaky valves or holes in the heart, this injection shows the abnormal flow of dye going in the wrong direction. You may feel a brief warm, flushed feeling over your body with this injection.
The catheter will also measure the pressures inside the heart, allowing your cardiologist to assess the heart’s pumping function and estimate the severity of valve defects. You may notice that the camera moves around your head and chest. Tilting the camera allows multiple shots to be taken at different angles and gives a more detailed study.
You may be awake during the procedure and see some of the pictures on the television screen. You might also be asked to take a deep breath and hold it for a few seconds. This is not painful, although you may feel some pressure at the groin site during the exchange of catheters. You will not feel the catheters moving through the blood vessels and into the heart.
Is catheterization safe?
Cardiac catheterization is an invasive procedure; therefore it has some risk. The risk is small, and the procedure is considered safe.
Some minor complications are nausea, allergic skin rash and heartbeat irregularity. Some patients develop bleeding at the insertion side and blood collects under the skin resulting in a local swelling or bruise. Rarely, catheterization is associated with more serious complications such as damage to blood vessels, blood clots, infection, abnormal heart rhythms, heart attacks or stroke. Death is extremely rare. Although most patients who have catheterizations do not experience any complications, you should be aware of the risk.
After your catheterization
After the procedure is completed, the catheters are removed. There are several ways to close the puncture made in the artery. The cardiologist may insert a collagen plug between the skin and the artery to seal it off. Or, the artery may be closed with an internal dissolvable stitch. If these methods are used, you will have 1—2 hours of bed rest following the procedure. Sometimes these methods cannot be used and the artery is sealed by manual pressure for 15—20 minutes. This requires 4—6 hours of bed rest. When the procedure is finished, your nurse will tell you what kind of method was used and what your recovery time will be.
You will be lifted onto a cart and transported to the recovery area where your nurse will continue to frequently monitor your vital signs and groin site. At this time, your family will be able to see you. Your cardiologist will come in and explain the findings of the catheterization and give you a picture of the results. In most cases, you will be able to have something to eat and drink shortly after returning to the recovery area.
After your have completed your bed rest, you will be asked to walk around. Your nurse will continue to monitor the groin site to make sure it is normal. If the incision site is normal, you will be given written discharge instructions. Generally, your activity will be limited during the first 24—48 hours after the procedure. You will also be given specific instructions on site care.
The doctor will inform you of your treatment, depending on the results of the catheterization and the severity of your symptoms. Some possible treatments are:
- Medications—A variety of medications are available to treat heart disease. Medications can be quite helpful in reducing symptoms and improving the quality of life in patients with heart disease.
- Coronary angioplasty—This is a non-surgical procedure used to open narrowed arteries. It is the same type of procedure as catheterization. A catheter with a balloon at its tip is passed into the narrow artery. The balloon is inflated, compressing the fatty deposits against the artery’s wall. This allows for better blood to flow to the heart muscle. Often, a stent is placed in the area to keep the artery walls propped open.
- Heart surgery—During coronary surgery, a blood vessel from the leg or chest is used to bypass the blockage. One end of the blood vessel is attached to the aorta, the other end is then attached to the artery just beyond the blockage. This creates a detour for the blood to flow freely to the heart muscle. During heart valve surgery, the defective valve is repaired or replaced with an artificial one.
No matter what treatment your cardiologist prescribes, it is important for you to take responsibility to care for your heart and your health. You can do this by reducing or eliminating certain risk factors such as:
- reducing fat and cholesterol in your diet
- lose weight
- exercise regularly—ask your cardiologist about enrolling in cardiopulmonary rehabilitation
- monitor your blood pressure
- reduce stress in your life