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Pulmonary Angiography
What is the test?An angiogram is an x-ray of your blood vessels that shows blockages or other abnormalities in veins or arteries. It uses a contrast dye (usually iodine dye), a liquid that helps blood vessels show up clearly on x-rays. The dye is injected into the body, and its movement is tracked by a series of x-rays. Two common types of angiography are cardiac catheterization with an angiogram of the coronary arteries, which supply blood to the heart, and pulmonary angiography, which examines arteries supplying blood to the lungs. Most often, a pulmonary angiogram is performed to see whether a pulmonary embolus, or blood clot, has traveled through the veins from the legs or pelvis into the lungs, blocking blood flow to a part of your lungs. A pulmonary angiogram is used if a less invasive test such as a ventilation-perfusion (V-Q) scan or a chest CT scan is inconclusive. How do I prepare for the test?During this procedure, local anesthetics (numbing agents) are used to minimize pain. Tell the cardiologist if you have ever had an allergic reaction to a local anesthetic or to contrast dyes. Also let your doctor know if you could be pregnant, since the x-rays used during this procedure can damage a fetus. You might be asked not to eat anything for six to eight hours before the test, to reduce the risk that you might become nauseated and vomit during the procedure. Tell the cardiologist if you're taking a nonsteroidal anti-inflammatory drug (NSAID) or other medicines that affect blood clotting and could increase the chance of bleeding from the procedure. You should also tell your doctor if you take insulin shots or blood sugar-lowering pills so that you can take steps to avoid dangerously low blood sugar, or hypoglycemia. What happens when the test is performed?You lie on your back as a medical technician connects you to a heart monitor and places an intravenous (IV) line in your arm. You may be given a sedative through the IV so that you are relaxed during the test. First, the doctor injects a local anesthetic into the skin. This might sting momentarily. After the skin is numb, the cardiologist inserts a catheter (a thin, hollow plastic tube) into a large vein-usually in your groin. Using live x-rays displayed on a video monitor as a guide, your doctor moves the catheter along the vein until it reaches your vena cava (the large blood vessel that carries blood to your heart from the rest of your body). then into the right side of your heart and finally into the pulmonary arteries that carry blood from the heart to your lungs. When the tip of the catheter is pointed into the pulmonary arteries, the doctor injects contrast dye, illuminating the arteries on an x-ray. If there is a blood clot in the lung arteries, it will show up on the x-ray. The procedure is repeated to visualize the other pulmonary arteries. What risks are there from the test?There are several potential risks. First, the catheter can irritate the heart, in rare cases causing a disturbance in the heart rhythm. Should this happen, the doctor can immediately use devices and medicines to restore a normal heart rhythm. Alert the doctors and nurses if you develop any chest discomfort, trouble breathing, or any other problem during the test. In addition, the contrast medium can sometimes impair kidney function. This effect is almost always temporary, but some people have permanent damage. Another possible complication is bleeding at the place where the catheter was inserted. If blood collects under the skin, it can form a large painful bruise called a hematoma. This usually resolves on its own, without requiring additional treatment. Occasionally, people are allergic to the contrast dye and develop a rash, hives, or difficulty breathing after the dye is injected. If this should occur, the medical staff in the catheterization laboratory have medicines available to treat the allergic reaction. The amount of radiation from this test is too small to be likely to cause harm. Must I do anything special after the test is over?Your doctor may ask you to lie flat for a few hours following the procedure or just keep your leg straight for up to 12 hours after the procedure. Often, a small plug or stitch is used to prevent bleeding from the artery that was entered to perform the catheterization. If you received a sedative, you might feel sleepy and shouldn’t drive or drink alcohol for one day after the catheterization. How long is it before the result of the test is known?As soon as the test is completed, your doctor will be able to look at the x-rays and determine whether there is a blood clot in your lungs. |
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