Adrenal Venous Sampling (AVS)

What is adrenal venous sampling?

Adrenal venous sampling (AVS or adrenal vein sampling) is a procedure that helps your healthcare provider determine if one or both of your adrenal glands are producing too much aldosterone. Aldosterone is an important hormone because it regulates blood pressure and electrolyte balance. If you have too much of it, it can cause high blood pressure and low potassium levels.

It involves an interventional radiologist using contrast dye to map the veins of your adrenal gland, then taking a sample of your blood from both your left and right adrenal veins. Then, they compare the blood samples to see if excess aldosterone is coming from the right, left or both adrenal glands. Your healthcare provider uses the results to determine your treatment plan.

Why is adrenal venous sampling done?

Healthcare providers perform AVS when you have primary aldosteronism (Conn’s syndrome). AVS tells your provider which adrenal gland is producing too much aldosterone. Knowing this lets them determine how they want to treat the condition.

Less commonly, adrenal vein sampling can locate a pheochromocytoma, which is a rare tumor that forms on your adrenal gland. Your provider may also recommend AVS for other hormonal imbalances that can result from adrenal gland dysfunction, but this is rare.

How should I prepare for adrenal vein sampling?

Adrenal venous sampling is an outpatient procedure that takes place in a hospital or surgical center. You’ll be awake for the procedure, but not feel any pain. This is performed with local anesthetic or conscious/light sedation. If you receive sedation, someone will need to drive you home after AVS.

Your healthcare provider may ask you to stop taking certain medications in the days leading up to AVS. Be sure to let your provider know which medications you take. You’ll also have to avoid eating or drinking the morning of the procedure.

What happens during adrenal venous sampling?

You can expect the following to occur during AVS:

1. Your healthcare provider will give you medication through an IV to stimulate your adrenal glands. An IV is a thin tube with a needle on the end. It can deliver medication directly into your bloodstream (through a vein).
2. You may also receive medication through the IV to relax you (sedation).
3. Your provider will apply an anesthetic to your groin to numb the area. This is where they’ll place the catheter. You won’t feel pain when they insert the catheter since your groin will be numb.
4. The interventional radiologist will make a cut in your groin. Then, they’ll pass a catheter into one of the veins in your groin. They’ll use an ultrasound to make sure they’re finding the right vein.
5. Next, they’ll insert a contrast material through the catheter. They’ll use an X-ray to guide the catheter up to your adrenal gland veins. (The X-ray will show them where the veins are.)
6. Once they find the veins, they’ll take a blood sample from both the right and left adrenal veins.
7. Then, they’ll remove the catheter from your groin and cover the incision with a bandage.

Does adrenal vein sampling hurt?

No, it shouldn’t hurt. You’ll receive medication so you don’t feel pain during the procedure. Some people say they feel warmth when the contrast material spreads through their veins. This is brief and shouldn’t be painful.

How long does AVS take?

The procedure can take up to two hours. Afterward, you’ll rest in a recovery room, which could take another two to four hours. Since everyone is different, you should always ask your healthcare provider how long you can expect AVS to last.

What happens after adrenal vein sampling?

After your healthcare provider gets the blood samples from your adrenal veins and removes the catheter, you’ll go to a recovery room. The blood samples are sent to a lab. A lab technician studies both samples to determine which gland is producing excess aldosterone.

Your healthcare team will monitor your vital signs while in the recovery room. Once this happens, and if your vitals remain stable, you’ll be discharged and sent home.

You should plan on resting for at least the next 24 to 72 hours. Your provider may give you rules to follow so your recovery goes smoothly. Ask your healthcare provider if you need to modify your daily routine while you recover.

What do the results of AVS tell you?

The results tell your provider if primary aldosteronism comes from one adrenal gland or both adrenal glands.

• If just one adrenal gland is producing too much aldosterone, your provider may recommend removing the gland (adrenalectomy) as treatment for primary aldosteronism.
• If both glands are overproducing aldosterone, medication is usually the best treatment.

What are the benefits of adrenal venous sampling?

AVS is a useful tool that can pinpoint if excess aldosterone is coming from one or both adrenal glands. While imaging tests can show tumors or enlarged glands, only this test can tell providers which gland is overproducing the hormone. This helps them determine the right treatment.

What are the risks of AVS?

Adrenal venous sampling is safe and effective, but it does carry risks. Possible risks include:

• Bleeding: Bleeding due to rupturing a vein is possible, but rare.
• Infection: There’s a small risk of infection where your provider cut your skin to insert the catheter.
• Allergic reaction: While rare, you could have an allergic reaction to the contrast material.
• Kidney damage: Contrast material can increase your risk of kidney damage if you already have a kidney condition.
• Vein rupture: This is when damage occurs to your vein when your provider insiders the needle. They may need to reschedule or repeat the procedure.
• Difficulty locating the veins: If your provider is unable to access one of your adrenal veins, they may need to reschedule or repeat the procedure.

What is the recovery time for adrenal vein sampling?

It can take a few days to recover from AVS. While it may be hard to sit still, allow yourself time to recover and relax. Jumping into your typical activities too soon could lead to complications like bleeding from the incision. Your groin area may feel a little tender from the catheter, and you may feel tired from the sedation.

Your healthcare provider will give you recovery instructions. They may ask you to avoid the following for up to three days:

• Driving a car.
• Operating heavy machinery.
• Lifting heavy objects.
• Doing strenuous physical activity.
• Bathing, swimming or sitting in water.
• Signing any legal documents.

If you have questions about what to avoid while you recover, ask your healthcare provider before you go home.

When should I call my healthcare provider?

Contact your provider if you have signs of complications after AVS like:

• Bleeding from the incision in your groin.
• Worsening pain.
• Fever.
• Nausea or vomiting.