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 use the test to find out what is causing your high blood pressure. They may look for a blood clot or tumor blocking your renal vein. If you may have renal hypertension, the radiologist will take blood samples from the vein.

This test is done by a radiologist. This is a doctor who specializes in radiology. For the test, the radiologist injects a contrast dye into the vein of your kidney. They use X-ray images to watch the dye as it flows through the blood vessels in the kidneys.

X-rays use a small amount of external radiation to create images of the insides of your body. A renal venogram is a type of X-ray.

Fluoroscopy is used during a renal venogram. Fluoroscopy is a kind of X-ray movie that shows organs and other internal structures in motion.

During the test, the radiologist may also take a blood sample (renin assay) from each vein in your kidneys. This is to see how much of a certain enzyme (renin) is in each sample. This can help them 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)

• Tumor

• High blood pressure caused by disease in the kidneys (renovascular hypertension)

Your healthcare provider may have other reasons to advise a renal venogram. CT scans and MRIs are used more often in place of a renal venogram. It is mainly used now as part of an exam to treat varicose veins of the testicles or ovaries. Talk with your provider about the reason for your test.

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 of 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:

• Bleeding

• Injury to nerves

• Blood clot

• Swelling caused by a collection of blood (hematoma)

• Infection

• Temporary kidney failure

• Damage to a vein or nearby artery. This can cause bleeding, blood clots, or an abnormal opening between the vein and artery.

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 health . Be sure to talk with your provider about any concerns you have before the procedure.

Some things can make a renal venogram less accurate. These include:

• Having oral contrast still in your body from a recent imaging test such as a CT scan, barium enema, or barium swallow (upper GI) X-ray

• Gas or stool in the intestines

How do I get ready for a renal venogram?

• Your healthcare provider will explain the procedure to you. Ask them any questions you 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 anything is not clear.

• You may be asked not to eat or drink for about 6 hours before the test.

• 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.

• Arrange to have someone drive you home afterward.

• Follow any other instructions your provider gives you to get ready.

Tell your healthcare provider:

• If you are pregnant or think you may be

• If you are allergic to contrast dye or iodine

• If you are sensitive to or are allergic to any medicines, latex, tape, or anesthetic medicines (local and general)

• All medicines you take. This includes prescription and over-the-counter medicines, all vitamins and herbal supplements you take.

• If you have had a bleeding disorder

• If you are taking blood-thinning medicine (anticoagulant), aspirin, or other medicines or herbal supplements that affect blood clotting. You may need to stop these medicines before the test.

What happens during a renal venogram?

You may have a renal venogram as an outpatient. This means you go home the same day. Or the test may be part of your stay in the hospital.

Generally, a renal venogram follows this process:

1. You will be asked to remove your jewelry or other objects that may get in the way of the test

2. If you are asked to remove clothing, you will be given a hospital gown to wear.

3. An IV (intravenous) line will be started in your arm or hand.

4. You may get medicine to help you relax (sedative) before the test.

5. You will lie on the X-ray table.

6. The nurse or technician will shave the skin in an area of your groin. They will clean the skin and inject local pain medicine. The radiologist will put a needle into a vein in your groin. This will be used to inject the contrast dye.

7. The radiologist will check your pulses below the injection site for the contrast dye. They will use a marker to note them. This is so that staff can check the circulation to the leg after the test.

8. The radiologist will put a long thin tube (catheter) into the vein. They will move the catheter until it reaches the renal vein. The radiologist will use fluoroscopy to see where the catheter is.

9. The radiologist will inject the contrast dye into the catheter. 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.

10. Tell the radiologist if you have trouble breathing, or if you have sweating, numbness, or heart palpitations.

11. The radiologist will take X-ray pictures. They will look at the X-rays on a screen.

12. Your radiologist may take a blood sample from the vein in your kidney and the IV in your arm or hand.

13. Once the test is done, the radiologist will remove the catheter. They will put pressure on the site to keep it from bleeding.

14. After the bleeding stops, they 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 check the injection site. They will also check the blood flow and feeling in the leg where the catheter was used.

You will need to lie flat in bed for at least 2 hours. Once your vital signs are stable and your injection site dressing is clean and dry, you will be taken to your hospital room or sent home.

You may be given pain medicine to ease pain or discomfort.

Once at home, watch the injection site for bleeding. A small bruise is normal. So is an occasional drop of blood at the site.

You should also watch the leg where the catheter was inserted for changes in temperature or color, pain, numbness, tingling, or loss of movement.

It's important to 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 you have any of these:

• Fever or chills

• Worse pain, redness, or swelling at the groin site

• Blood or other fluid coming from the groin site

• Coolness, numbness, tingling, or other changes in the leg

Your healthcare provider may give you other instructions.

Next steps

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 you will get the results

• Who to call after the test or procedure if you have questions or problems

• How much you will have to pay for the test or procedure