Information for patients scheduled for cerebral or spinal angiography
Your doctor has requested that we perform a procedure called an angiogram to evaluate some of your blood vessels. The angiograms we perform are to evaluate the blood vessels of the head, neck, brain, or spine. The angiogram you have performed will be specifically designed to answer the questions important for your care, so only certain blood vessels will be studied. These may include arteries such as the aorta, the carotid arteries, the vertebral arteries, the subclavian arteries, the spinal arteries, and the capillaries and veins of the head, neck, or spine, depending upon what parts of your circulatory or central nervous system are to be examined. The interventional neuroradiologist who performs your examination will discuss the specific reasons for your procedure and what blood vessels we plan to study during the course of the examination.
Method: This type of examination is called an "invasive procedure" because we must put a catheter (a long, narrow, flexible plastic tube) into a blood vessel in order to perform the procedure. Usually, this catheter is introduced through an artery in your groin and then directed to the vessels to be examined. Once the catheter is in position, a contrast agent ("dye") is injected which makes the selected blood vessels visible on X-ray. Let us know about any allergy you have to drugs, contrast agents, or dyes. Many images are taken during each injection using cameras above and beside you. The number of vessels studied and the number of injections performed will depend upon the questions we are trying to answer with the examination. The length of the examination will also vary from patient to patient, from 30 minutes to several hours, with the average length being about 1-1.5 hours.
This procedure is most often performed using "local anesthesia" (numbing medication injected into the area before the needle and catheter are placed into the artery or vein) and intravenous sedation (medication injected into your IV line to make you comfortable and a little drowsy). At various points during the examination, you will be asked to hold still and to hold your breath while the pictures of the blood vessels are being recorded. Since motion will blur the images, it is important to remain as still as possible when you are asked.
After the necessary blood vessels have been studied, the catheter will be removed, and in most cases, the radiologist will hold pressure over the puncture site for at least 10 minutes so that you will not bleed from the small hole the catheter created in the artery or vein. In selected cases, a special device may be used to close the hole in the artery. You will need to stay in bed following the procedure and keep your leg or arm (depending on where the catheter was inserted) straight and still in order to avoid bleeding. You will be observed for a short time after the procedure in our area, then go back to your room or to a treatment or recovery area, depending on your schedule for the remainder of the day. The nurses will be checking on you from time to time to be certain that you are not bleeding, but should you notice any bleeding, be certain to inform your nurse so that pressure can be re-applied to the puncture site. Side effects: You will initially feel some needle sticks where the catheter is to be placed. These are for the local anesthetic, which will sting some when first injected but will then make the area numb. You may feel the needle stick that punctures the artery and the initial placement of the catheter at its insertion site, but you will not feel the catheter inside your blood vessels and you should not feel any further discomfort with catheter movement after it is first inserted. When the contrast ("dye") is injected, you will probably feel a sensation of heat in the area of the body the blood vessel feeds, but only for a few seconds until the contrast washes out. The degree of heat felt varies from person to person and from blood vessel to blood vessel. It is not unusual to have some mild tenderness or bruising for a few days at the site the catheter was introduced.
Potential risks: Just as with any invasive procedure, there are some risks involved in undergoing an angiographic procedure.
The contrast agent ("dye") is eliminated from your body in a matter of hours through your kidneys. If you have poor kidney function (e.g. have an elevated creatinine level, require dialysis, or need a special renal diet) the contrast agent could injure your kidneys temporarily or permanently. If you have clotting abnormalities, you could bleed more than a normal amount from the hole in the artery or vein punctured for catheter introduction. Even with normal clotting functions, about 5% of people have enough bleeding under the skin to form a "hematoma", a collection of blood that could cause more extensive tenderness and bruising than normal.
Less than 1% of people experience temporary neurologic deficits (weakness, numbness, or impaired speech or vision lasting from a few seconds for up to 24 hours) after the procedure. About 0.3% of people (3 in 1000) suffer permanent neurologic deficits (a stroke, which can range from minor to major) from diagnostic angiographic procedures such as these. Rarely, other complications may occur. For example, clots may form on catheters, the procedure may damage arteries, or severe allergic reactions to the contrast may cause breathing or circulatory problems. Fortunately, serious complications are rare, and this institution has the most experienced staff, the highest caseload, and best neuroangiographic facility in the region to perform these procedures.
Alternatives: There is currently no ideal substitute for conventional angiography. Doppler ultrasound (sonography), CT scanning, CT angiography (CTA), MR scanning, and MR angiography (MRA) provide some useful information about blood vessels, but cannot provide the accuracy and resolution provided by catheter angiography.