Cardiac Catheterization and Coronary Angiography

What is Cardiac Catheterization and Coronary Angiography?

Cardiac catheterization is a test to check your heart and coronary arteries. It is used to check blood flow in the coronary arteries, blood flow and blood pressure in the chambers of the heart, find out how well the heart valves work, and check for defects in the way the wall of the heart moves. This test is also used to check for heart problems that have been present since birth (congenital heart defect).

One of the more common diseases that a heart patient can have is coronary artery disease, or plaque build-up with obstruction in the coronary arteries. Coronary angiography is a component of a cardiac catheterization procedure in which dye is injected into the opening of the coronary arteries in order to find out if you have disease in your coronary arteries, and, if so, pinpoint the location of the plaque and the severity of the blockage that may have built up. This is generally done to determine whether you may need bypass surgery or angioplasty.

Why It Is Done?

Cardiac catheterization and coronary artery disease

Most commonly cardiac catheterization is done to:

• Check blood flow and blood pressure in the chambers of the heart.
• Check blood flow in the coronary arteries and, if you have coronary artery disease (CAD), determine whether surgery or another type of procedure is needed to open the blocked blood vessels.

Other reasons for having a cardiac catheterization

Cardiac catheterization is also done to:

• Check the pumping action of the heart.
• Find out if a congenital heart defect is present and how severe it is.
• Check blood flow through the heart after surgery.
• Fine out how well the heart valves work.
• Check the pumping action of the heart.
  
  

How Do I Prepare for the Test

Tell your doctor if you:

• Are allergic to the iodine dye used in the contrast material or any other substance that contains iodine, or have ever had a serious allergic reaction (anaphylaxis) from any substance.
• Are allergic to any medicines.
• Have any bleeding problems or take blood-thinning medicine.
• Are or might be pregnant.
• Have kidney disease. The contrast material used during cardiac catheterization can cause kidney damage in people who have poor kidney function. If you have a history of kidney problems, blood tests (creatinine, blood urea nitrogen) may be done before the test to confirm that your kidneys are functioning properly.
• Have diabetes, especially if you take metformin (Glucophage). Your doctor may instruct you to stop the medicine before the test.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will indicate.

Most cardiac catheterization and coronary angiography tests are performed as an outpatient procedure. Therefore, you may have to arrange for someone to take you home after the test. You should not drive yourself home on the day of the test.

Do not eat or drink (except for a small amount of water) after midnight before the test. If you are taking any medicines, ask your doctor whether you should take them on the day of the test.

Before the test, remove any necklaces, bracelets, rings, or other jewelry.

Be sure to empty your bladder completely just before the test

How Is Cardiac Catheterization Done

This test is performed in the cardiac catheterization laboratory
("cath lab").

You will be asked to lie on a flat table under a large X-ray machine. Several small metal leads (electrodes) will be attached to your chest and arms with a special paste. These leads are connected to an electrocardiogram (EKG, ECG) machine that continuously records the electrical activity of your heart during the test.

A device called a pulse oximeter that measures oxygen levels in your blood and monitors your pulse may be clipped to your finger.

An intravenous (IV) needle will be inserted into a vein in one of your arms to give you fluids or medicine during the procedure. You will receive a medicine to help you relax (sedative) through the IV line. You will be awake during the procedure but, because of the sedative, you may not be able to remember much about the procedure.

The thin flexible tube (cardiac catheter) is usually inserted in your groin where an artery and vein, the femoral artery and vein are usually close to the skin surface. Other sites that may be used are the crease of your elbow (brachial artery) or your wrist (radial artery). The catheter insertion area will be shaved and cleansed with an antiseptic solution before the test. Sterile towels will be draped over your arm or leg, except for the area over the catheter insertion site.

A local anesthetic will be injected into the skin at the insertion site. A blood vessel is punctured by a special needle or exposed by making a small incision in the skin so that the catheter can be passed into the blood vessel. The catheter is slowly advanced through the blood vessel into your body. The catheter tip is moved into various positions in the heart's vessels and chambers while the doctor watches its progress on the imaging screen. Pressures within the heart chambers can be measured, and blood samples may also be obtained through the catheter..

A small amount of dye (contrast material) will be injected through the catheter into your heart chamber or one of your coronary arteries. Pictures show the arteries as the dye moves through them. You may be asked to cough to help clear the contrast material out of your heart or breathe deeply and hold your breath.

If you desire, your doctor may allow you to watch the video monitor so you can see the images of your heart and coronary arteries.

You may be given nitroglycerin under your tongue to help open up your coronary arteries and obtain optimal pictures of you coronary arteries.  Other medications may be administered during the test for greater relaxation or other reasons as needed.

The entire procedure usually takes about one hour, but it may take longer if additional tests are required. The length of the test is not an indication of the seriousness of your condition.

What Can I Expect After the test?

The catheter will be removed from the insertion site. To prevent bleeding, the site may need to be closed using pressure, stitches, or another method or special seal. For example, if the catheter was inserted in your wrist or groin, firm pressure will be applied to the area for about 10 to 15 minutes to seal the tiny opening in the artery that the catheter produced and prevent bleeding. Then a pressure dressing may be placed over the area. If the catheter was inserted in your elbow, a few stitches will be used to close the wound.

After the test, you will be taken to an observation room and a health professional will periodically monitor your heart rate, blood pressure, and temperature and check for signs of bleeding at the insertion site. The pulse, color, and temperature of the arm or leg in which the catheter was inserted will also be checked periodically.

If the catheter was inserted in your leg, you will have to lie in bed with your leg extended for 4 to 6 hours, and occasionally longer depending on the exact procedure done and your medical condition. After that, you can move about freely, but you should avoid strenuous activity for at least 3 days.

You should drink plenty of liquids for several hours after the test. This will help flush the contrast material out of your body.

Depending on the results of the test, you may be sent home either after a 4 to 6-hour observation period or on the next day. If any stitches were placed in your arm, they may be removed in 5 to 7 days.

What are the Risks of the Procedure

Cardiac catheterization and coronary angiography are invasive tests which are performed with remarkable safety in most cases.  Complications of cardiac catheterization are rare, but they can be life-threatening. Serious complications are more likely to occur in people who are critically ill or elderly. Serious complications may include:

• Heart attack or stroke. On rare occasions, the catheter tip can dislodge a blood clot or some debris from the inside wall of the artery.
• Blockage of blood flow to the arm or leg below the area where the catheter was inserted. Surgery may be needed to restore the blood circulation.
• Irregular heartbeats (arrhythmias). In rare cases, this procedure may produce a persistent abnormal heart rhythm. The abnormal rhythm usually corrects itself or becomes normal after treatment with medicine.
• Kidney damage. In rare cases, the contrast material can damage the kidneys, possibly causing kidney failure. People with diabetes and kidney disease are at greatest risk for kidney damage.
• An abnormal collection of fluid in the space between the heart and the sac that surrounds it (cardiac tamponade).
• Puncture of the heart or one of its blood vessels. This could require immediate open-heart surgery to repair.
• Allergic reaction to the contrast material, with hives and itching and, rarely, shortness of breath, fever, and shock. These allergic reactions can usually be controlled with medicines.

Less serious complications include:

• Pain, swelling, and tenderness at the catheter insertion site.
• Irritation of the vein by the catheter (superficial thrombophlebitis). This can usually be treated with warm compresses.
• Bleeding at the catheter site.
• A collection of blood under the skin where the catheter was inserted (hematoma). This usually goes away in a few days.
• Difficulty urinating after the procedure.

There is always a slight risk of damage to cells or tissues from being exposed to any radiation, including the low levels of X-ray used for this test. However, the risk of damage from the X-rays is usually very low compared with the potential benefits of the test.

How Will I Get the Results of the Test

Your doctor will often be able to talk to you about some of the results during or immediately after the test.  In some instances, findings are made which require immediate attention.  This possibility will be discussed prior to your consenting to the procedure.  For example, some patients with unstable heart conditions who are found to have serious blockage in the coronary arteries during the cardiac catheterization may need to undergo percutaneous coronary intervention, or angioplasty, to open the blockage immediately.

Under more typical and stable situations, your doctor will review the findings of the procedure before you go home.  Occasionally, when further study or calculations are needed, the final results may take several days to review with you.

Many conditions can affect the results of a cardiac catheterization. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and medical history.

What Should I Do When I Get Home After an Outpatient Procedure

• Someone should drive you home.
• You should rest that evening, either in bed or in a chair. 
• Avoid excess walking
• Watch for any of the complications listed under “less serious complications” above.  Call your doctor if you suspect a problem.

Cardiac catheterization and coronary angiography are amongst the most common procedures performed.  You should not be fearful of the test, but it is important to understand the importance of the test and test results.  Any concerns before the test should be discussed with your doctor.  It many instances, the findings of this test could be life-saving to you.