About the Procedure
Angiography is a diagnostic procedure where a small tube [catheter] is inserted into a blood vessel through a pinhole puncture in the skin usually in the thigh. The tube is then navigated under imaging guidance to the blood vessel that has to be studied. The procedure is done under local anesthesia and the patient is generally discharged the same day. Patients with impaired kidney function, especially those who also have diabetes, may have further deterioration in the kidney function with iodinated contrast. In these cases carbon dioxide angiography is a safe option.However, CO2 gas cannot be used to study the blood vessels of the chest and the brain. In these cases MR angiography may be a better choice.
Procedures Details
What are some common uses of the procedure?
Catheter angiography is used to examine blood vessels in key areas of the body, including the:
- brain
- kidneys
- pelvis
- legs
- lungs
- heart
- neck
Interventional Radiologist’s use this procedure to:
- identify disease and aneurysms in the aorta or in other major blood vessels
- detect atherosclerosis disease in the carotid artery of the neck, which may limit blood flow to the brain and cause a stroke
- identify a small aneurysm or arteriovenous malformation inside the brain
- detect atherosclerotic disease that has narrowed the arteries to the legs and help prepare for surgery
- indicate disease in the renal artery or visualize blood flow to help prepare for a kidney transplant
- guide surgeons making repairs to diseased blood vessels, such as implanting or evaluating a stent
- detect injury to one of more arteries in trauma patients
- evaluate the details of arteries feeding a tumor prior to surgery
- identify dissection in the aorta or its major branches
- show the extent and severity of atherosclerosis in the coronary arteries
- plan for a surgical operation, such as coronary bypass
- identify the source of internal bleeding, such as a stomach ulcer
How should you prepare for the procedure?
You should inform us of any medications you are taking and if you have any allergies, especially to contrast material. Also inform your doctor about recent illnesses or other medical conditions.
You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, eye glasses and any metal objects or clothing that might interfere with the x-ray images.
Women should always inform their physician if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy because radiation can be harmful to the fetus. If an x-ray is necessary, precautions will be taken to minimize radiation exposure to the baby.
If you are breastfeeding at the time of the exam, you should ask your radiologist how to proceed. It may help to pump breast milk ahead of time and keep it on hand for use after contrast material has cleared from your body.
If you are going to be given a sedative during the procedure, you may be asked not to eat or drink anything for four to eight hours before your exam.
You should not drive for 24 hours after for your exam and you should arrange for someone to drive you home. Because an observation period is necessary following the exam, you may be admitted to the hospital for an overnight stay.
What does the equipment look like?
The equipment typically used for a fluoroscopy examination consists of a box-like structure containing the x-ray tube and an image intensifier at the other end that converts the x-ray images into a video image and sends them to a television-like monitor that is located in the examining room or in a nearby room. The image intensifier is suspended over a table on which the patient lies. A unit under the table holds the x-ray film or image recording plate that captures the images.
How does the procedure work?
Catheter angiography works much the same as a regular x-ray exam.
X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small burst of radiation that passes through the body, recording an image on photographic film or a special image recording plate.
Different parts of the body absorb the x-rays in varying degrees. Dense bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow more of the x-rays to pass through them. As a result, bones appear white on the x-ray, soft tissue shows up in shades of gray and air appears black.
When a contrast material is introduced to the bloodstream during the procedure, it clearly defines the blood vessels being examined by making them appear bright white.
How is the procedure performed?
This examination is usually done on an day care basis.
A nurse or technologist will insert an intravenous (IV) line into a small vein in your hand or arm.
A small amount of blood will be drawn before starting the procedure to make sure that your kidneys are working and that your blood will clot normally. A small dose of sedative may be given through the IV line to lessen your anxiety during the procedure.The area of the groin or arm where the catheter will be inserted is shaved.
The are most commonly the upper thigh is cleaned, and numbed with local anesthetic. The radiologist will make a small needle puncture in the skin where the catheter can be inserted into an artery. The catheter is then guided through the arteries to the area to be examined. After the contrast material is injected through the catheter and reaches the blood vessels being studied, several sets of x-rays are taken.During injection of the contast agent you may be akid to hold your breath for a few seconds. Most people get a warm feeling in the region of examination during injection of contrast.
Then the catheter is removed and the incision site is closed by placing pressure on the area for approximately 10 minutes (or by using a special closure device).
When the examination is complete, the patient will be asked to wait until the technologist determines that the images are of high enough quality for the radiologist to read.
Your intravenous line will be removed.
A catheter angiogram may be performed in less than an hour; however, it may last several hours.
Who interprets the results and how will I get them?
A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will share the results with you.
What are the benefits vs. risks? Benefits Risks What are the limitations of Catheter Angiography?
- Angiography may eliminate the need for surgery. If surgery remains necessary, it can be performed more accurately.
- Catheter angiography presents a very detailed, clear and accurate picture of the blood vessels. This is especially helpful when a surgical procedure or some percutaneous intervention is being considered.
- By selecting the arteries through which the catheter passes, it is possible to assess vessels in several specific body sites. In fact, a smaller catheter may be passed through the larger one into a branch artery supplying a small area of tissue or a tumor; this is called superselective angiography.
- Unlike computed tomography (CT) or magnetic resonance (MR) angiography, use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example is finding an area of severe arterial narrowing, followed by angioplasty and placement of a stent.
- The degree of detail displayed by catheter angiography may not be available with any other noninvasive
procedure
- No radiation remains in a patient’s body after an x-ray examination.
- X-rays usually have no side effects.
- If you have a history of allergy to x-ray contrast material, your radiologist may advise that you take special medication for 24 hours before catheter angiography to lessen the risk of allergic reaction. Another option is to undergo a different exam that does not call for contrast material injection.
- If a large amount of x-ray contrast material leaks out under the skin where the IV is placed, skin damage can result. If you feel any pain in this area during contrast material injection, you should immediately inform the technologist.
- Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant.
- Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
- The risk of serious allergic reaction to contrast materials that contain iodine is rare, and radiology departments are well-equipped to deal with them.
- There is a small risk that blood will form a clot around the tip of the catheter, blocking the artery and making it necessary to operate to reopen the vessel.
- If you have diabetes or kidney disease, the kidneys may be injured when contrast material is eliminated through the urine. In such cases Carbon dioxide gas may be used for angiography.
- Rarely, the catheter punctures the artery, causing internal bleeding. It also is possible that the catheter tip will separate material from the inner lining of the artery, causing a block downstream in the blood vessel.
Patients with impaired kidney function, especially those who also have diabetes, are not good candidates for this procedure.CO2 gas cannot be used to study the blood vessels of the chest and the brain. In these cases MR angiography may be a better choice.
Patients who have previously had allergic reactions to x-ray contrast materials are at risk of having a reaction to contrast materials that contain iodine. If angiography is essential, a variety of methods is used to decrease risk of allergy:
- You may be given one or more doses of a steroid medication ahead of time.
- Contrast material without iodine may be used instead of standard x-ray contrast.