(Angiogram-Kidneys, Renal Angiography, Renal Arteriogram, Renal Arteriography)
What is a renal angiogram?
An angiogram, also called an arteriogram, is an X-ray image of the blood vessels. It is performed to evaluate various vascular conditions, such as an aneurysm (ballooning of a blood vessel), stenosis (narrowing of a blood vessel), or blockages.
A renal angiogram is an angiogram of the blood vessels of the kidneys. A renal angiogram may be used to assess the blood flow to the kidneys.
Fluoroscopy is often used during a renal arteriogram. Fluoroscopy is the study of moving body structures similar to an X-ray "movie." A continuous X-ray beam is passed through the body part being examined, and is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail.
How is an angiogram performed?
In order to obtain an X-ray image of a blood vessel, an intravenous (IV) or intra-arterial (IA) access is necessary so that contrast, also known as X-ray dye, can be injected into the body's circulatory system. This contrast dye causes the blood vessels to appear opaque on the X-ray image, thus allowing the physician to better visualize the structure of the vessel(s) under examination.
Many arteries can be examined by an angiogram, including the arterial systems of the legs, kidneys, brain, and heart.
For a renal angiogram, arterial access may be obtained through a large artery such as the femoral artery in the groin. Once access is obtained, the catheter is advanced to the renal artery, contrast is injected, and a series of X-ray pictures is made. These X-ray images show the arterial, venous, and capillary blood vessel structures and blood flow in the kidneys.
Other related procedures that may be used to diagnose kidney problems include kidney, ureters, and bladder (KUB) X-ray, computed tomography (CT scan) of the kidneys, intravenous pyelogram, kidney biopsy, kidney scan, kidney ultrasound, magnetic resonance imaging (MRI), and renal venogram. Please see these procedures for additional information.
How do the kidneys work?
The body takes nutrients from food and converts them to energy. After the body has taken the food that it needs, waste products are left behind in the bowel and in the blood.
The kidneys and urinary system keep chemicals, such as potassium and sodium, and water in balance, and remove a type of waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.
Two kidneys, a pair of purplish-brown organs, are located below the ribs toward the middle of the back. Their function is to:
Remove liquid waste from the blood in the form of urine
Keep a stable balance of salts and other substances in the blood
Produce erythropoietin, a hormone that aids the formation of red blood cell
Release calcitriol, the active form of vitamin D, which helps maintain calcium for bones and for normal chemical balance in the body
Regulate blood pressure
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule.
Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.
Reasons for the procedure
A renal angiogram may be performed to detect abnormalities of the blood vessels of the kidneys. Such abnormalities may include, but are not limited to, the following:
Stenosis or vasospasm (spasm of the blood vessel)
Arteriovenous malformation (an abnormal connection between the arteries and veins)
Thrombosis (a blood clot within a blood vessel) or occlusion (blockage of a blood vessel)
Renovascular hypertension (systemic high blood pressure caused when the renal artery is narrowed)
Other conditions that may be detected by a renal angiogram include tumors, hemorrhage (bleeding), complications of kidney transplantation, and the invasion of a tumor into the blood vessels. An angiogram may be used to deliver medications directly into the tissue or organ needing treatment, such as the administration of a clotting medication to a bleeding site or cancer medication into a tumor.
Renal angiograms are less frequently use with CT and MRI scans being more commonly used for diagnosing these conditions. Renal angiogram may also be recommended after a previous procedure, such as a CT scan, indicates the need for further information.
There may be other reasons for your doctor to recommend a renal angiogram.
Risks of the procedure
You may want to ask your doctor about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of X-rays, so that you can inform your doctor. Risks associated with radiation exposure may be related to the cumulative number of X-ray examinations and/or treatments over a long period of time.
If you are pregnant or suspect that you may be pregnant, you should notify your health care provider. Radiation exposure during pregnancy may lead to birth defects.
There is a risk for allergic reaction to the contrast. Patients who are allergic to or sensitive to medications, contrast dye, or iodine should notify their doctor. Also, patients with kidney failure or other kidney problems should notify their doctor as contrast can worsen existing kidney disease.
Because the procedure involves the blood vessels and blood flow of the kidneys, there is a small risk for complications involving the kidneys. These complications may include, but are not limited to, the following:
Hemorrhage due to puncture of a blood vessel
Injury to nerves
Thrombus. A clot in the blood vessel
Hematoma. An area of swelling caused by a collection of blood
Transient kidney failure
Damage to artery or arterial wall, which can lead to blood clots
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
Certain factors or conditions may interfere with the accuracy of a renal angiogram. These factors include, but are not limited to, the following:
Remaining contrast substances from recent contrast studies, such as a barium enema
Gas or stool in the intestines
Before the procedure
Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
You will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.
Notify your doctor if you have ever had a reaction to any contrast, or if you are allergic to iodine
Notify your doctor if you have or have had any prior kidney problems or kidney disease
Notify your doctor if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
You will need to fast for a certain period of time prior to the procedure. Your doctor will notify you how long to fast, whether for a few hours or overnight.
Notify your health care provider if you are pregnant or suspect you may be pregnant.
Notify your doctor of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
Notify your doctor if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
You may receive a sedative prior to the procedure if necessary. You may also receive an anticholinergic medication, which acts to slow down the production of saliva in the mouth, inhibit the production of acid in the stomach, and slow down the activities of the intestinal tract, among other effects. If you receive this medication, you may notice that your mouth feels dry.
Depending on the site used for injection of the contrast, the recovery period may last up to 12 to 24 hours. You should be prepared to spend the night if necessary.
Your doctor may request a blood test prior to the procedure to determine how long it takes your blood to clot. Other blood tests may be done as well.
Based on your medical condition, your doctor may request other specific preparation.
During the procedure
A renal angiogram may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.
Generally, a renal angiogram follows this process:
You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
You will be given a gown to wear.
You will be asked to empty your bladder prior to the start of the procedure.
You will be positioned on the X-ray table.
An intravenous (IV) line will be inserted in your arm or hand.
You may have a blood test done to test your kidney function.
You will be connected to an EKG monitor that records the electrical activity of the heart and monitors the heart during the procedure using small, adhesive electrodes. Your vital signs (heart rate, blood pressure, and breathing rate) will be monitored during the procedure.
The radiologist will check your pulses below the puncture site and mark them with a marker so that the circulation to the limb below the site can be checked after the procedure.
A needle will be inserted into an artery in your groin after the skin is cleansed and a local anesthetic is injected. On occasion, an artery in the elbow area of the arm may be used. If the groin or arm site is used, the site will be shaved prior to insertion of the IV. If the arm site is used, a blood pressure cuff will be applied to the arm below the IV site and inflated to prevent flow of the contrast dye into the lower arm.
Once the needle has been placed, a catheter (a long, thin tube) will be inserted into the artery at the groin or arm site. The catheter will be advanced into the aorta near the renal arteries. Fluoroscopy will be used to verify the location of the catheter.
An injection of contrast will be given. You may feel some effects when the dye is injected into the line. These effects include a flushing sensation, a salty or metallic taste in the mouth, a brief headache, or nausea and/or vomiting. These effects usually last for a few moments.
You should notify the radiologist if you feel any breathing difficulties, sweating, numbness, or heart palpitations.
After the contrast dye is injected, a series of X-rays will be taken. The first series of X-rays shows the arteries, and the second series shows capillary and venous blood flow.
Depending on the specific study being performed, there may be one or more additional injections of contrast dye.
Once sufficient information has been obtained, the catheter will be removed and pressure will be applied over the area to keep the artery from bleeding.
After the bleeding stops, a dressing will be applied to the site. A sandbag or other heavy item may be placed over the site for a period of time to prevent further bleeding or the formation of a hematoma at the site.
After the procedure
After the procedure, you will be taken to the recovery room for observation. The circulation and sensation of the leg where the injection catheter was inserted will be monitored. A nurse will monitor your vital signs and the injection site.
You will remain flat in bed in a recovery room for several hours after the procedure. If the groin or arm site was used, the leg or arm on the side of the injection site will be kept straight for up to 12 hours.
You may be given pain medication for pain or discomfort related to the injection site or to having to lie flat and still for a prolonged period.
You will be encouraged to drink water and other fluids to help flush the contrast dye from your body.
You may resume your usual diet and activities after the procedure, unless your doctor advises you differently.
When you have completed the recovery period, you may be returned to your hospital room or discharged to your home. If this procedure was performed as an outpatient, you should have another person drive you home.
Once at home, you should monitor the injection site for bleeding. A small bruise is normal, as is an occasional drop of blood at the site.
If the groin or arm was used, you should monitor the leg or arm for changes in temperature or color, pain, numbness, tingling, or loss of function of the limb.
Drink plenty of fluids to prevent dehydration and to help pass the contrast.
You may be advised not to do any strenuous activities or take a hot bath or shower for a period of time after the procedure.
Notify your doctor to report any of the following:
Fever and/or chills
Increased pain, redness, swelling, or bleeding or other drainage from the groin injection site
Coolness, numbness and/or tingling, or other changes in the affected extremity
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.