Adrenal venous sampling

This leaflet is designed for patients who have been advised to have an adrenal venous sampling procedure as part of the treatment for high blood pressure.

What is adrenal venous sampling?

Adrenal venous sampling is a procedure which involves inserting a small plastic tube into the veins from the adrenal glands and taking a small sample of blood. This sample is then sent to the laboratory for testing.

Normally veins do not show up on an ordinary x-ray so a special dye, called contrast medium, is injected into the veins through a fine plastic tube called a catheter to make them visible.

Why do I need adrenal venous sampling?

Your doctors have asked for you to have adrenal venous sampling because they suspect that you may have high blood pressure related to the adrenal glands. This can also be related to low levels of potassium in the blood. This disorder is sometimes called primary hyperaldosteronism, or Conn’s syndrome.

Occasionally, adrenal venous sampling might be performed for other reasons, usually related to high levels of hormones produced by the adrenal glands.

Who has made the decision?

The consultant in charge of your case and the radiologist performing the adrenal venous sampling will have reviewed your medical history, and come to the conclusion that this is the best way of diagnosing your condition.

However, you will also have the opportunity for your opinion to be taken into account, and if, after discussion with your doctors, you do not want the procedure carried out, you can decide against it.

What are the benefits?

Adrenal venous sampling can provide important information about the possible causes of high blood pressure. This information can be used to guide further care, including planning for possible surgery to treat an adrenal cause of high blood pressure.

What happens before the procedure?

Sometimes your blood pressure medication will need to be altered in advance of the procedure, as certain types can interfere with the results. If this is the case your medical team will get in touch beforehand. You will be asked to attend the hospital on the day of the procedure, either to the Endocrine Investigation Unit, or to the Radiology Day Unit.

A doctor or nurse will take a history from you.

• You might have a small needle put into a vein in your arm for a medication drip to be set-up. This infusion is called synacthen, or ACTH.
• Standard blood tests might be carried out.
• You may eat a light meal beforehand.
• If you have any allergies you must let your doctor know.
• If you take any medications to thin the blood (anticoagulants or antiplatelets) please let us know beforehand, as these will need to be stopped a certain length of time before the procedure. Examples include:
  • warfarin, dalteparin, enoxaparin, tinzaparin, dabigatran, rivaroxaban, apixaban, clopidogrel, ticagrelor.
  • Low dose aspirin (75mg) is safe to continue.
  • Please discuss with a doctor before stopping any medicines, as sometimes other treatment will need to be given.
• If you have previously reacted to intravenous contrast medium (the dye used for CT scans), you must also tell your doctor about this.

Who will be performing the adrenal venous sampling?

A specially trained doctor called an interventional radiologist will be performing your adrenal venous sampling.

Radiologists have special expertise in using x-ray equipment and in interpreting the images produced. They will look at these images while carrying out the procedure. The radiologist will be assisted by a radiographer and nurses.

What happens during the adrenal venous sampling?

• You will get dressed into a hospital gown.
• You will lie on the x-ray table, generally flat on your back.
• You will have a monitoring device attached to your finger, and will have a blood pressure cuff placed around your arm.
• The procedure is performed under sterile conditions and the radiologist and scrub nurse will wear sterile theatre gowns and operating gloves.
• Your groin area will be cleaned with an antiseptic solution.
• Local anaesthetic will be injected to numb the area and stop any pain.
• A small tube will then be inserted into the groin vein.
• Smaller tubes will be inserted into the adrenal veins to take the samples.
• When the tubes are in the right position, some contrast dye will be injected to confirm the position before the samples are taken.
• Once all the samples have been taken the tube in the groin vein will be removed and pressure will be applied to stop any bleeding.

Will the adrenal venous sampling hurt?

Some discomfort might be felt in the skin and deeper tissues during injection of the local anaesthetic. You may feel a warm sensation for a few seconds when the dye is injected and feel like you are passing urine.

There will be a nurse, or another member of the clinical staff, in the room looking after you.

If the procedure does become uncomfortable, please let a member of staff know, and more pain relief can be given.

How long does the adrenal venous sampling take?

Every patient’s situation is different, and it is not always easy to predict how complex or how straightforward the procedure will be. Typically, the procedure will last one hour.

What will happen after the adrenal venous sampling?

You will be taken back to the Radiology Day Unit for two hours of bed rest after the procedure.

Nursing staff might carry out routine observations including taking your pulse and blood pressure and will also check the treatment site.

If you experience pain or sickness let the nursing staff know.

You will need someone to pick you up and take you home. You must not drive or use public transport to get home.

You should rest for the rest of the day of the procedure, and possibly the next day depending on your recovery. You can then resume normal activities. Please avoid heavy lifting for 48 hours following the procedure.

What are the possible risks?

Adrenal venous sampling is a very safe procedure, but as with all procedures there are some possible risks.

The adrenal veins are very small, so there is a chance that samples will not be able to be obtained from the veins, or that the samples that are taken cannot provide enough information to make a diagnosis. If this happens then your doctors will discuss whether the procedure should be repeated, or if another test might be required.

Other risks from the procedure include:

• A small risk of bleeding and bruising at the site of venous access in the groin.
• A very small risk of infection.
• A very small risk of causing a blood clot to form in the vein, which can move to the lungs (known as a pulmonary embolism).
• A very small risk of injury to the adrenal glands.

Your doctor will discuss the risks with you, and give you the opportunity to ask any questions.

Radiation

You have been referred for an interventional radiology procedure to help deliver your treatment. A specialist in radiology agrees that this is the best procedure to treat your clinical condition and that the benefit of the examination is greater than the risk.

The x-ray involves a dose of ionising radiation equivalent to a few months or years of natural background radiation which we are all exposed to every day.

Ionising radiation can cause cell damage that may turn cancerous however the risk of this happening from your examination is considered low.

Depending on the length of the procedure there might also be a small risk of an excess radiation dose to the skin leading to short- and long-term effects such as reddening of the skin, and burns. If this happens as a result of this procedure, you will receive further advice following the procedure. The dose delivered will be kept as low as is practicable.

For further information, please visit the Imaging-radiology page.

Conclusion

Some of your questions about adrenal venous sampling should have been answered by this leaflet, but remember that this is only a starting point for discussion about your treatment with the doctors looking after you.

This document has been adapted from one prepared by the British Society of Interventional Radiology (BSIR).

Medication

Bring all of your medicines (including inhalers, injections, creams, eye drops or patches) and a current repeat prescription from your GP.

Please tell the ward staff about all of the medicines you use. Please speak with your nurse if you wish to take your medication yourself (self-medicate) during your stay. Pharmacists visit the wards regularly and can help with any medicine queries.

MyChart

We strongly encourage you to sign up for MyChart. This is the electronic patient portal at Cambridge University Hospitals that enables patients to securely access parts of their health record held within the hospital’s electronic patient record system (Epic). It is available via your home computer or mobile device

More information is available on our website: CUH - MyChart.

Contacts/further information

Angiography Department: 01223 348920.