What is a renal venogram?
A renal venogram is an imaging test to look at the veins in and around your kidneys.
Your healthcare provider may also use the test to find out what is causing your high
blood pressure (hypertension).
This test is done by a radiologist who is a doctor that specializes in radiology.
For the test, the radiologist injects a contrast dye into the kidney. He or she uses
X-ray images to watch the dye as it flows through the blood vessels in the kidneys.
X-rays use a small amount of radiation to create images of your bones and internal
organs. A renal venogram is one type of X-ray.
Fluoroscopy is used during a renal venogram. Fluoroscopy is a kind of X-ray movie.
During the test, the radiologist may also take a blood sample (renin assay) from each
vein in your kidneys. The radiologist will see how much of a certain enzyme (renin)
is in each sample. This can help him or her find what is causing your high blood pressure.
Why might I need a renal venogram?
You may need a renal venogram to help your healthcare provider find problems in the
renal vein or with blood flow in your kidneys. These problems may include:
- Blood clot (renal vein thrombosis)
- High blood pressure in the kidneys (renovascular hypertension)
Your healthcare provider may have other reasons to recommend a renal venogram.
What are the risks of a renal venogram?
You may want to ask your healthcare provider about the amount of radiation used during
the test. Also ask about the risks as they apply to you.
Consider writing down all X-rays you get, including past scans and X-rays for other
health reasons. Show this list to your provider. The risks of radiation exposure may
be tied to the number of X-rays you have and the X-ray treatments you have over time.
Tell your healthcare provider if you:
- Are pregnant or think you may be pregnant. Radiation exposure during pregnancy may
lead to birth defects.
- Are allergic to or sensitive to any medicines, contrast dye, or iodine. Because contrast
dye is used, there is a risk for allergic reaction to the dye.
- Have kidney failure or other kidney problems. In some cases the contrast dye can cause
kidney failure. You are at higher risk for this if you take certain diabetes medicines.
Possible complications of a renal venogram include:
- Injury to nerves
- Blood clot (embolus)
- Swelling caused by a collection of blood (hematoma)
- Temporary kidney failure
- Damage to a vein. This can cause blood clots.
You should not have renal venography if you have a severe blockage (thrombosis) in
the large vein that brings blood from your lower body to your heart (inferior vena
cava) or a blockage in the renal vein.
You may have other risks depending on your specific health condition. Be sure to talk
with your provider about any concerns you have before the procedure.
Certain things can make a renal venogram less accurate. These include:
- Having contrast dye still in your body from a recent imaging test
- Gas or stool in the intestines
- Taking certain medicines. These include blood pressure medicines, water pills (diuretics),
the hormone estrogen, and birth control pills.
- Too much salt in your diet
How do I get ready for a renal venogram?
- Your healthcare provider will explain the procedure to you. Ask him or her any questions
you have about the procedure.
- You may be asked to sign a consent form that gives permission to do the procedure.
Read the form carefully and ask questions if anything is not clear.
- You'll be asked to not eat or drink liquids (fast) for several hours before the procedure.
If your provider plans to take a blood sample during the test, you will need to cut
back on the amount of salt you eat before the procedure.
- Tell your healthcare provider if you are pregnant or think you may be.
- Tell your healthcare provider if you are allergic to contrast dye or iodine.
- Tell your healthcare provider if you are sensitive to or are allergic to any medicines,
latex, tape, or anesthetic drugs (local and general).
- Tell your healthcare provider about all medicines you are taking. This includes prescriptions,
over-the-counter medicines, and herbal supplements.
- Tell your healthcare provider if you have had a bleeding disorder. Also tell your
provider if you are taking blood-thinning medicine (anticoagulant), aspirin, or other
medicines that affect blood clotting. You may need to stop these medications before
- You may get medicine to help you relax (sedative) before the test. You will need to
have someone drive you home afterward.
- Follow any other instructions your provider gives you to get ready.
What happens during a renal venogram?
You may have a renal venogram as an outpatient or as part of your stay in the hospital.
The way the test is done may vary depending on your condition and your healthcare
Generally, a renal venogram follows this process:
- You will be asked to remove your jewelry or other objects that may get in the way
of the test
- If you are asked to remove clothing, you will be given a gown to wear.
- An intravenous (IV) line will be started in your arm or hand.
- You will lay on the X-ray table.
- The nurse or technician will shave the skin in an area of your groin. He or she will
clean the skin and inject local pain medicine. The radiologist will put a needle into
a vein in your groin.
- The radiologist will check your pulses below the injection site for the contrast dye.
He or she will use a marker to note them. This is so that staff can check the circulation
to the leg after the test.
- The radiologist will put a long thin tube (catheter) into the vein. He or she will
move the catheter until it reaches the renal vein. The radiologist may use fluoroscopy to
see where the catheter is.
- The radiologist will inject the contrast dye. You may feel a flushing sensation, a
salty or metallic taste in the mouth, a brief headache, or nausea or vomiting. These
effects usually last for a few moments.
- Tell the radiologist if you have trouble breathing, or if you have sweating, numbness,
or heart palpitations.
- The radiologist will take X-ray pictures. He or she will be able to see the X-rays
on a monitor.
- You may be asked to lie face down for more X-rays.
- Your radiologist may take a blood sample from the IV.
- Once the test is done, the radiologist will remove the catheter. He or she will put
pressure on the site to keep the artery from bleeding.
- After the bleeding stops, he or she will put a dressing on the site. The radiologist
may put something heavy on the site for a period of time. This will help stop bleeding
and keep blood from collecting (hematoma) at the site.
What happens after a renal venogram?
You will be taken to the recovery room. A nurse will watch your vital signs and the
injection site. He or she will check the circulation and sensation in the leg where
the catheter was used.
You will need to lie flat in bed for at least 2 hours. Once your blood pressure, pulse,
and breathing are stable and you are alert, you will be taken to your hospital room
or sent home.
You may be given pain medicine to ease pain or discomfort from the injection site
or from having to lie flat and still.
Once at home, you should watch the injection site for bleeding. A small bruise is
normal. So is an occasional drop of blood at the site.
You should watch the leg for changes in temperature or color, pain, numbness, tingling,
or loss of movement.
Drink plenty of fluids to help the contrast dye leave your body. Fluids will also
keep you from getting dehydrated.
You may not be able to do any strenuous activities or take a hot bath or shower for
a period of time after the test.
Tell your healthcare provider if any of these occur:
- Fever or chills
- Increased pain, redness, swelling, or bleeding or other fluid draining from the groin
- Coolness, numbness, tingling, or other changes in the leg
Your healthcare provider may give you other instructions, depending on your situation.
Before you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- What results to expect and what they mean
- The risks and benefits of the test or procedure
- What the possible side effects or complications are
- When and where you are to have the test or procedure
- Who will do the test or procedure and what that person’s qualifications are
- What would happen if you did not have the test or procedure
- Any alternative tests or procedures to think about
- When and how will you get the results
- Who to call after the test or procedure if you have questions or problems
- How much will you have to pay for the test or procedure