What is Catheter Angiography?

A type of x-ray done to image blood vessels in various parts of the body, including the heart, brain and kidneys, so as to determine whether the vessels are diseased, narrowed, enlarged or blocked altogether. After passing a catheter through an artery leading to the body area of interest, a contrast material is injected to highlight the vessels when x-rays are taken.
 

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What are some common uses of the procedure?

• Detect narrowing or blockages of a blood vessel, identify abnormally dilated blood vessels, and determine the site of internal bleeding.
• Detect the narrowing or blockage of a blood vessel of the legs, this pain is usually caused in the lower/ upper limb.
• Detect atherosclerotic disease in the carotid artery of the neck, which may limit blood flow to the brain and even cause a stroke.
• Identify an intracranial aneurysm or other disorders of the blood vessels in the brain.
• Evaluate disease in the renal artery or help prepare for a kidney transplant.
• Determine the state of the aorta and detect an aneurysm of this vessel.
• Identify a source of bleeding, such as a stomach ulcer.
• Help prepare for surgery on diseased blood vessels in the legs of patients who have severe leg pain when walking.
• Show the extent and severity of atherosclerosis in the coronary arteries.

Surgeons sometimes use angiography to plan an operation, like coronary bypass surgery, or to decide on the best surgical procedure. Using catheter angiography as an aid to see inside blood vessels, surgeons can repair diseased vessels from within using tiny instruments and inserting a stent to keep the vessel open. Furthermore, a radiologist can treat anomalies that were detected.
 

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How should I prepare for the procedure?

• Fast: if you are to have a sedative before the procedure, you may be asked not to eat or drink anything (except sips of water to take pills) for four to eight hours ahead of time. Some hospitals, however, allow clear fluids until shortly before the examination.
• Safe return: if you will be going home the same day, you should arrange alternative transportation.
• Clothing: after removing jewellery and donning a hospital gown, you should empty your bladder.
• Blood sample: a small amount of blood will be drawn before starting to make sure that your kidneys are working and that your blood will clot normally, and an IV line will be set up.
• Consent: before the procedure you will have to give your consent. This usually involves a face-to-face talk with a physician, but in some cases you will read a brief description of angiography or view a videotape instead.
• Allergies: you should tell the physician before the exam begins.
• Pregnancy: the radiology staff should know if there is a possibility that you may be pregnant.

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What does the angiography equipment look like?

The angiographic catheter is a long plastic tube about as thick as a strand of spaghetti. The x-ray equipment is mounted on a C-shaped gantry with the x-ray tube itself beneath the table on which the patient lies. Over the patient is an image intensifier that receives the x-ray signals after they pass through the patient, amplifies them, and sends them to a TV monitor.

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How does the procedure work?

The x-rays passed through the patient's body are absorbed to different degrees by various tissues, and each type of tissue has its own distinctive appearance. A stream of dye, or contrast material, is injected into the catheter to obtain a detailed picture from inside the blood vessel. X-ray images are stored in a computer or captured on film.

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How is the procedure performed?

A small dose of sedative usually is given through the IV line, not to make the patient sleep but to "take the edge off." Local anaesthesia is injected into the skin at the site of puncture, which most often is at the top of the leg at the site of the femoral artery. A small incision is made after cleaning and shaving the skin at this site in order to introduce the catheter into the artery. The radiologist threads the catheter through the arterial system to the desired location, and then injects the contrast material. Usually several sets of x-rays are taken and, after the procedure is completed, the catheter is removed and the puncture site closed by compressing it for about 10 minutes (or by using a special closure device). You will have to lie flat for two to six hours after angiography, depending on the reason for the exam, the catheter size, and the type of device used to close up the artery. During this time you should inform the nurse if you notice any bleeding, swelling or pain at the site where the catheter entered the skin. The entire procedure may take less than an hour or as long as several hours.

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What will I experience during the procedure?

Injecting a local anaesthetic may sting briefly but makes the rest of the procedure pain-free. You will not feel the catheter in your artery, but when contrast material is injected you may have a feeling of warmth or, occasionally, a slight burning sensation. The most difficult part of the procedure may be lying flat for several hours.

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Who interprets the results and how do I get them?

The radiologist will examine all of the images and report his findings to your physician, who in turn will discuss them with you.

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What are the benefits vs. risks?

Benefits

• 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.
• Assess vessels in several specific body sites.
• Possibility to combine diagnosis and treatment in a single procedure.
• Degree of detail displayed may not be available by any non-invasive procedure.

Risks

• Allergic reaction to the dye, and this could lead to a skin reaction, a drop in blood pressure, difficulty breathing, or even loss of consciousness.
• Blood forming a clot about the tip of the catheter, blocking the artery and making it necessary to operate to reopen the vessel.
• Kidneys may be injured when contrast material is eliminated through the urine. If kidney disease is already present it may become worse.
• 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 "down stream."
• Special care is taken during x-ray examinations to ensure maximum safety for the patient by shielding the abdomen and pelvis with a lead apron, with the exception of those examinations in which the abdomen and pelvis are being imaged. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.

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What are the limitations of Catheter Angiography?

Patients with impaired kidney function, especially those who also have diabetes, are not good candidates for this procedure. Patients who previously have had allergic reactions to x-ray contrast materials are at risk of having a reaction to contrast materials that contain iodine. But, if angiography is essential, giving a dose of steroid ahead of time may reduce the risk. Catheter angiography should be done very cautiously—if at all—in patients who have a tendency to bleed.

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