August 2014

Cardiac Catheterization

Cardiac Catheterization

Cardiac catheterization is a diagnostic procedure for evaluating certain problems with the heart and its blood supply. The procedure involves the placement of a long, thin tube (called a catheter) into the heart to measure pressures, inject dye, and take X-ray pictures. This procedure normally takes two to three hours.

 

Cardiac catheterization provides information about:

  • The blood flow through the heart and coronary arteries (blood vessels that supply blood to the heart muscle) or
       other major blood vessels that carry blood to and from the heart.
  • The pressure within the various heart chambers.
  • A detailed picture of the structure of various parts of the heart and vascular (blood vessel) system.
  • The heart's pumping ability.
  •  

    This information may be necessary in order for your doctor to decide whether surgery is necessary or not and what type of problem exists within your heart and circulatory system. It allows him to create an appropriate treatment plan for you.

     

    The Normal Heart

    Information about the normal heart may help you to better understand any problem involving your heart or vascular system that may be found during cardiac catheterization.

    The heart is a hollow, muscular organ which lies in the center of the chest under the breastbone. It has four chambers. The two upper chambers (atria) receive blood, and the two lower chambers (ventricles) pump blood. A wall (septum) divides the heart into a right and left side. Four valves in the heart serve as one-way gates to keep blood flowing in the proper direction.

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    Diagram 1.

     

    Diagram 1 shows the normal pathway of blood through the heart. Blood from all parts of the body returns through veins to the right atrium (see arrow). This blood has had most of its oxygen removed by the body's tissues. From the right atrium, blood goes to the right ventricle, which pumps it to the lungs where it is replenished with oxygen. From the lungs, oxygen-rich blood (arrow) returns to the left atrium of the heart and into the larger and more muscular left ventricle.

    When the left ventricle contracts, it sends blood into the largest artery of the body, the aorta. The aorta takes this oxygenated blood to smaller arteries throughout the body.

    The heart, like all body organs, requires oxygen to perform its work. This oxygen is supplied by a system of arteries, called the coronary arteries, which branch off the aorta just after the aorta leaves the left ventricle. Although there is great variation, most people have three major coronary arteries: the right coronary artery, left anterior descending branch and left circumflex branch. These arteries run along the surface of the heart and divide into smaller branches which penetrate the muscular walls of the heart to nourish it with oxygen.

     

    Hospitalization Versus Outpatient

    Unless your medical condition requires prior hospitalization, most patients are admitted to the hospital the same day as the cardiac catheterization, then go home the following morning. In this case, the necessary blood tests, chest X-rays, and ECGs (electrocardiograms) will be obtained at a clinic visit the day prior to the procedure or the morning of the procedure.

     

    Consent

    A catheterization team physician will explain why the procedure is necessary and what risk is involved. The degree of risk is related in part to your health condition and varies with each patient. The procedure requires written consent.

    Generally your physician or the nursing staff will also review the procedure with you and your family to clarify any information and answer any questions.

     

    Allergies

    Be sure to tell your physician at least one day before the procedure if you have a history of allergies to any of the following: medications, shell fish, and/or X-ray dye.

     

    The Procedure

    The procedure itself is divided into three stages preparation, the procedure and the recovery.

     

    The Preparation Stage

    The entry site of the catheter is scrubbed with an antiseptic soap solution and covered with a sterile drape. This may also involve shaving body hair from potential catheter insertion sites. The most commonly used site is the inside part of your thigh (groin area), but occasionally the forearm is used. Skin preparation helps ensure a clean site and reduces the chance of infection where the catheter enters the skin. This drape protects the area of insertion of the catheter from being exposed to infection.

    Generally you will be asked to not eat or drink anything after midnight of the evening before the test. The only exception to this is when small amounts of water are necessary for taking medications. If the catheterization is not scheduled until the afternoon, your physician may allow you to have clear liquids for breakfast, after which you must not eat or drink.

    Before you go to the Catheterization Laboratory, you should use the bathroom because it will be a couple of hours before you return to your room. You will not be able to use the urinal or bedpan during the procedure.

    You will wear a hospital gown without pajama bottoms to permit easy access to the catheter insertion site. You may wear your glasses, and if you have dentures, please wear them.

    Before you go to the Catheterization Laboratory, you will be given medication to help you relax. The medication does not put you to sleep, because you need to be awake during the test to follow instructions.

    Your family members should wait in your room or in a nearby visitor's lounge. They will be notified when you return to your room.

     

    The Procedure Itself - Insertion Of The Catheter - Taking Measurements

    The physician first numbs the area where the catheter is to be inserted with a local anesthetic. This allows the insertion of the catheter to be virtually painless. At most you will feel a small needle prick then a slight burning sensation from the anesthetic. After that you should not have significant pain or discomfort. On occasion patients will experience some pressure sensations as the catheter is moved or changed.

    The physician then inserts a larger needle into the blood vessel that the catheter is to be inserted into. A small guide wire is passed through the needle and the needle is removed. Next, a small plastic tube (catheter) is threaded over the wire and guided through the vessel and into the chambers of the heart.

    An X-ray is soon taken to confirm that the catheter tip is in the desired location. If it is then the guide wire is removed. If not it is moved to where your surgeon wants it to be. Once in position the catheter is connected to an instrument which records pressures in the different heart chambers. The catheter is often moved about for a while to take pressure reading but eventually it is placed exactly where the surgeon wants it depending on which part of the heart he is evaluating.

    Once the catheter is in the place the surgeon wants it to be, a clear plastic hood may be placed over your head for approximately five minutes. The purpose of this is to analyze the air that you exhale. By doing this, the physician can determine the pumping efficiency of your heart. During this part of the test, you should not talk--just relax and breathe normally.

    Blood samples may also be drawn through the catheter. After this, contrast material (dye) is injected, while X-ray motion pictures are taken. During the injection of dye, you might feel a warm sensation that spreads from head to toe and lasts 30 to 60 seconds. You may be asked to cough or hold your breath at certain times during the procedure.

    When the test is finished, the physician removes the catheter and pressure is applied to the area of insertion for about 15 to 20 minutes. The insertion site is then covered with a small sterile dressing and you are returned to your room. In some cases it may be necessary to move you first to a special care area where your heart's rhythm can be carefully monitored for a while.

     

    Recovery - After The Procedure

    When you return to your room, you will be required to lie flat on your back for a minimum of six hours. The head of the bed may be elevated slightly after 2 hours, if there has been no bleeding. It is important to keep the leg that was used in the procedure straight and immobile during this time to minimize the chances of bleeding. A sheet may be placed over the knee of the affected leg to remind you not to bend that knee. After six hours, if there has been no bleeding from the catheter insertion site, the staff will assist you in turning onto your side. Most patients are allowed out of bed the next morning.

    If the procedure was done through an entry site in your forearm, you will be permitted to get out of bed with assistance in one to two hours. Your arm, however, will be kept straight on a stiff armboard.

    After you return to your room, a nurse frequently checks your blood pressure, pulse, and catheterization site for signs of bleeding. The pulse and temperature of your feet are checked, too. You are instructed to apply firm pressure to the catheter insertion site when moving or coughing. You may have difficulty with urination because of lying flat during the six hours of recovery. If so, a Foley catheter can be placed in your bladder until the following morning.

    An intravenous solution may be given to ensure that you have an adequate fluid intake. Your physicians will determine when you can eat or drink. Your initial meal is all liquids. Unless you are advised otherwise, you are encouraged to drink plenty of fluids.

     

    Discomfort

    If you experience any pain or discomfort (backaches may occur during bed rest after catheterization), ask your nurse for pain medication. If you should experience any chest discomfort or note any bleeding at the catheterization site, you should notify a nurse immediately.

     

    Results

    Your physician will discuss your test results either on the afternoon of the procedure or the next day. A plan for your therapy will be discussed.

     

    The Day After The Procedure

    The following day you may be up and about as you were before the test. It is important that a nurse be present to assist you when you first get out of bed, because you may feel lightheaded. You are encouraged to drink fluid freely. If you have any more questions or concerns, please ask your physician or nurse.