Cardiac Catheterization

What is a cardiac catheterization (also called cardiac cath)?

In cardiac catheterization (often abbreviated as "cath"), a very small catheter (hollow tube) is advanced from a blood vessel in the groin through the aorta into the heart.

Once the catheter is in place, several diagnostic techniques may be used. The tip of the catheter can be placed into various parts of the heart to measure the pressure within the chambers. The catheter can be advanced into the coronary arteries and a dye injected into the arteries (coronary angiography or arteriography). With the use of fluoroscopy (a special type of x-ray), the physician can tell where any blockages in the coronary arteries are located as the dye moves through the arteries. A small sample of heart tissue can be obtained during the procedure to be examined later under the microscope for abnormalities (this is called a biopsy).

You are awake during the procedure, although you will receive a small amount of sedating medication prior to the procedure.

Due to advances in knowledge, technology, and techniques, cardiac cath is often performed on an outpatient basis, meaning that the procedure is done early in the day and you may go home the same day. However, catheterization may be done on patients who are already hospitalized and thus, will remain in the hospital after the procedure. Also, some patients who were at home before the procedure are admitted to the hospital after the procedure in certain circumstances.

Why is cardiac catheterization done?

Your physician may schedule you for a cardiac catheterization if you have recently had one or more episodes of cardiac symptoms such as, but not limited to the following:

• chest pain
• shortness of breath
• dizziness
• fatigue
• a combination of any of these symptoms

A screening examination or test such as an EKG may be done to evaluate symptoms such as those listed above. If such a test suggests a possibility of some type of heart disease process that needs to be explored further, the physician may determine that a cardiac cath is necessary for more definitive diagnostic data.

Other reasons for the cath procedure include, but are not limited to, evaluation of myocardial perfusion (blood flow to the heart muscle) after heart attack, heart bypass surgery, coronary angioplasty (the opening of a coronary artery using a balloon or other method), or stent placement (a tiny expandable metal coil placed inside the artery to keep the artery open). There may be other reasons for your physician to recommend a cath procedure as well.

Cardiac catheterization is also used to detect and evaluate heart conditions or diseases, including the following:

• coronary artery disease
  Coronary artery disease (CAD) is the narrowing of the arteries caused by a buildup of fatty material within the walls of the arteries. This buildup causes the inside of the arteries to become rough and narrowed, limiting the supply of oxygen-rich blood to the heart muscle.
  
  Fortunately, the knowledge and technology exist to restore blood flow to heart tissue when the coronary artery blockages are diagnosed. One of several diagnostic procedures used to diagnose and evaluate coronary artery disease is cardiac catheterization.
  
  
• valvular heart disease
  In order to keep the blood flowing forward during its journey through the heart, there are valves between each of the heart's pumping chambers. The tricuspid valve is between the right atrium and the right ventricle; the pulmonary (or pulmonic) valve is between the right ventricle and the pulmonary artery; the mitral valve is between the left atrium and the left ventricle; and the aortic valve is between the left ventricle and the aorta.
  
  If the heart valves become damaged or diseased, they may not function properly. Dysfunction of heart valves may be either stenotic (stiff) or insufficient (leaky). When one or more valves become stiff, or stenotic, the heart muscle must work harder to pump the blood through the valve. Some reasons why heart valves become stenotic include infection (such as rheumatic fever or staph infections) and aging. If one or more valves become leaky, or insufficient, blood leaks backwards, which means that less blood is pumped in the proper direction. Cardiac catheterization is used to diagnose and evaluate the severity of valvular heart disease.
  
  
• congestive heart failure
  Congestive heart failure (CHF) is a condition that occurs when the heart is unable to pump blood sufficiently. Despite its name, a diagnosis of CHF does NOT mean the heart is about to stop beating. The term "failure" refers to the fact that the heart muscle is failing to pump blood in the normal manner because it has become weakened.
  
  CHF may appear suddenly after an acute episode such as a heart attack that severely damages and weakens the heart muscle, or it may progress over a much longer period of time. One of the several diagnostic procedures that is used to diagnose congestive heart failure is a cardiac catheterization.
  
  
• congenital heart disease
  Congenital heart disease refers to one or more of several conditions which are present at birth (birth defects). Cardiac catheterization is performed to determine the presence and severity of congenital cardiac abnormalities. Some congenital heart conditions include:
  
  
  • atrial septal defect (ASD)
    In this condition, there is a hole between the two upper chambers of the heart. Although blood from the left atrium flows into the right atrium through this defect, there may be few, if any, symptoms of this condition in infants and children, except for a possible heart murmur (an abnormal sound heard through the stethoscope when listening to the heart).
    
    
  • ventricular septal defect (VSD)
    In this condition, a hole occurs between the two lower chambers of the heart. Because of this hole, blood from the left ventricle flows back into the right ventricle, due to higher pressure in the left ventricle. This causes an extra volume of blood to be pumped into the lungs by the right ventricle, which can create congestion in the lungs.
    
    
  • patent ductus arteriosus (PDA)
    In the fetus, a hole occurs naturally between the pulmonary artery and the aorta. However, shortly after birth, this hole closes on its own. Sometimes, the hole does not close, which means that oxygenated blood from the aorta returns back to the lungs through the pulmonary artery, causing congestion in the lungs, an increased workload on the heart, and may lead to an enlarged heart.
    
    
  • obstruction defect
    This general term refers to several different congenital conditions that cause an obstruction in the flow of blood through the heart. Obstruction defects include:
    
    
    • aortic stenosis
      A stiffening of the aortic valve (the valve between the left ventricle and the aorta).
      
      
    • pulmonary stenosis
      A stiffening of the pulmonary (or pulmonic) valve (the valve between the right ventricle and the pulmonary artery).
      
      
    • bicuspid aortic valve
      A defect in the aortic valve, in which there are only two leaflets (flaps) in the valve instead of the normal three leaflets.
      
      
    • subaortic stenosis
      A narrowing of the left ventricle just below the aortic valve.
      
      
    • coarctation of the aorta
      A narrowing or constriction of the aorta, which obstructs blood flow from the heart to the rest of the body tissues.

• tetralogy of Fallot
  In this condition, there are actually four separate defects occurring at the same time: ventricular septal defect, pulmonary stenosis, overriding aorta (the outflow tract of the aorta begins just above the ventricular septal defect instead of at the normal location in the left ventricle), and right ventricular hypertrophy (enlargement of the muscle of the right ventricle).
  
  
• transposition of the great vessels
  In this condition, the outflow tracts of the aorta and the pulmonary artery are switched during fetal development. This means that unoxygenated blood flows out to the body through the pulmonary artery and oxygenated blood flows back into the lungs through the aorta. By itself, this condition cannot sustain life after birth. However, there are usually accompanying defects that permit some oxygenated blood to get out to the body tissues.
  
  
• tricuspid atresia
  In this condition, the tricuspid valve between the right atrium and right ventricle is missing. By itself, this would mean that no blood can be pumped into the lungs to receive oxygen; however, there are usually accompanying defects that allow some blood to go to the lungs.

How is a cardiac catheterization done?

Before the cardiac cath procedure, you will receive instructions on what to do the night before the test. These instructions may include nothing to eat or drink for a period of six or more hours before the procedure and changes in the directions for taking some of your medications.

Once you arrive for your procedure, an intravenous (IV) line will be started in your hand or arm prior to the procedure for injection of medication and to administer IV fluids if needed. The area designated as the cath site (groin or arm) will be shaved and washed with an antiseptic soap. You will receive a sedative medication in your IV before the procedure to help you relax. The pulses in your feet will be checked and the location where the pulses are felt will be marked on the skin with a marker. This is done in order to be able to compare the strength of these pulses after the procedure.

Once the preparations for the procedure have been completed, you will be taken to the room where the procedure will actually take place. The room will feel cool. You will lie on a firm but padded x-ray table and will be connected to equipment that will monitor your heart rhythm, blood pressure, and oxygen levels. A nurse will accompany you at all times. Please feel free to ask questions at any time.

You will lie flat on your back during the entire procedure. There will be several monitor screens in the room, showing your vital signs (EKG, heart rate, blood pressure, breathing rate, and oxygen level), the images of the catheter being moved through the body into the heart, and the structures of the heart as the dye is injected.

The cath lab is a sterile area, so everyone in the room will wear gowns, masks, and caps. The physician and assistants actually performing the procedure will wear sterile gloves. A large x-ray camera will be above the table to make pictures of the procedure.

The cath site (groin or arm) will be cleansed again with antiseptic soap, and then sterile towels and a sheet will be placed around this area. A numbing medication (lidocaine, or xylocaine) will be injected into the cath site.

click image to enlarge

Once the numbing medication has taken effect, the physician will make a small incision at the insertion site. A sheath, or introducer, is inserted into the blood vessel exposed by the incision. The sheath is a plastic tube through which the catheter will be inserted into the blood vessel and advanced into the heart. It will be very important for you to remain still during the procedure so that the catheter placement is not disturbed and to keep from causing damage to the insertion site.

The catheter is inserted through the introducer into the blood vessel. The physician advances the catheter through the blood vessels into the heart. This is done by watching the catheter on the monitor and guiding it into the proper structures. The catheter may be advanced into either the right or left side of the heart, or both sides, depending on what the physician is looking for.

Pressures are obtained at various locations within the heart structures. Blood samples may be withdrawn to assess oxygen levels at various places in the heart. Dye may be injected into one or more of the heart's chambers to assess blood flow and the heart's structure. When the dye is injected, you may notice a feeling of warmth or even a hot flash. This sensation will last for only a few seconds. The catheter may be advanced into the coronary arteries, where dye is injected to determine if there are any blockages and where the blockages, if any, are located.

At certain points during the procedure, you may be asked to take in a deep breath and hold it for a few seconds. You may also be asked to cough during the procedure. If you notice any discomfort or pain, such as chest pain, neck or jaw pain, back pain, arm pain, shortness of breath, or breathing difficulty, let the physician know.

Once the physician has obtained the information he/she was looking for during the procedure, the catheter will be removed from the insertion site.

The physician or an assistant will hold pressure on the insertion site for about 15 to 20 minutes, so that the blood can begin to form a clot at the site and stop the bleeding. Once the physician or assistant is satisfied that the bleeding has stopped, a very tight bandage will be placed on the site. A sandbag may be placed on top of the bandage for additional pressure on the site, especially if the site is the groin.

You will be assisted to slide from the table onto a stretcher so that you can be taken to the recovery area. NOTE: You will not be allowed to bend your leg nearest the insertion site, if the insertion was done in the groin, for several hours. To help you remember to keep your leg straight, the knee of the affected leg will be covered with a sheet and the ends will be tucked under the mattress on both sides of the bed to form a type of loose restraint.

Once the procedure is complete, you will go to a recovery area for a few hours, where a nurse will monitor the circulation of your arm or leg, and check your dressing for signs of bleeding. The nurse will also monitor your heart rhythm and blood pressure.

Notify your nurse immediately if you notice warmth, bleeding, pain at the catheter site, chest pressure or tightness, or other pain after the procedure. If you need to cough, sneeze, or laugh, hold pressure on the bandage on the insertion site. During this time, you will still have your leg or arm immobilized, and will need to remember not to bend the leg or arm.

You will be encouraged to drink fluids after the procedure to aid in flushing the cath dye from your system. The cath dye will remain in your system for some time and will cause you to urinate frequently. Please ask the nurse to assist you, as it is essential that the cath site not be bent during this time. You may also be given a light meal after the procedure.

You may raise the head of the bed and move around once you have completed the mandatory time for bed rest. You will require a nurse's assistance when you initially stand up to walk. Before you are discharged home, your nurse will give you instructions on care of the catheter site, problems or symptoms to report, and instructions regarding activities and medications.

If the procedure is done on an outpatient basis, you will be allowed to leave after you have completed the recovery process, usually about six to eight hours after the procedure is finished.

You will most likely feel tired for a day or so after the procedure. The catheter site in your leg or arm may be sore for a few days. You may have other pain or discomfort for a day or so due to lying still for a long period of time during the procedure and the recovery period.

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