While adrenal vein sampling (AVS) is the gold standard for diagnosing subtypes of primary hyperaldosteronism (Conn’s syndrome), it is not always necessary for every patient. The decision to perform AVS depends on individual circumstances, and many patients may not need it at all. This is where consulting with an expert adrenal surgeon and team becomes crucial, as they can help determine whether the procedure is appropriate or could be avoided altogether. 

Why Adrenal Vein Sampling Isn’t Always Necessary

Conditions Where Adrenal Vein Sampling Is NOT Needed 

In certain cases, AVS may not be required, particularly when the diagnosis is already clear or other diagnostic tools provide sufficient information. These are patients we often refer to as an “ALDO slam dunk”. This means that the diagnosis is so obvious that no further confirmatory testing and procedures are needed. These patients may go straight to curative adrenal surgery.  

Here are some instances where AVS might be unnecessary: 

1) Patients with Clear Imaging Evidence: For patients with unilateral adrenal adenomas (tumors) seen on imaging scans, surgery may be the obvious next step without needing AVS. If the clinical presentation and imaging suggest an aldosterone-producing adenoma (and the other gland is completely normal), surgery can be performed directly without the need for adrenal vein sampling. The patients also tend to have favorable prognostic markers (i.e. features that make them likely to have an excellent response to surgery).  

Some of these prognostic factors include: 

• Female gender 

• Young age (<60 years old) 

• Shorter duration of hypertension 

• Good response to Spironolactone/Eplerenone 

• High plasma aldosterone concentration (PAC) level 

• Very low renin level 

• High ARR (aldosterone renin ratio) 

• Absence of target organ damage (primarily absence of chronic kidney disease, i.e. elevated creatinine, and GFR) 

2) Patients with Bilateral Disease: If imaging or tests suggest that both adrenal glands are producing excess aldosterone, AVS may be unnecessary, especially if the tumors on both sides need to be addressed by surgery. In these cases, a bilateral, partial (also known as function-preserving) adrenalectomy may be the treatment path and AVS would not alter the course of treatment.

3) Clear Surgical Candidates: When a patient has clear evidence of unilateral hyperaldosteronism and imaging shows an unequivocal tumor, especially if the patient has classic symptoms of Conn’s syndrome, surgery is the most straightforward approach. In such cases, AVS may only add unnecessary risk and expense.

4) Patient preference: Some patients prefer to avoid AVS, which is a reasonable consideration. Since Dr. Carling at the Carling Adrenal Center performs immunohistochemistry (technical name is CYP11B2 staining), evaluating aldosterone-producing cells on the pathology in all cases of primary hyperaldosteronism, he knows whether unilateral adrenal surgery is sufficient or if partial (function-preserving) adrenal surgery may be necessary in the future. Pathology provides much more accurate information than what is obtained with AVS. However, the obvious downside is you don’t have this information until the adrenal tissue has been evaluated by our adrenal pathologist. 

5) Previous adrenalectomy: In patients who have previously had adrenal surgery, there is no need for AVS. Since the study depends on the ability to compare one side to the other, AVS in this scenario renders the study useless.  

Risks of Unnecessary Adrenal Vein Sampling 

Performing adrenal vein sampling when it is not necessary can not only waste time and resources but also increase the risk of complications. Since AVS is an invasive procedure, it carries risks such as bleeding, adrenal infarction, or vein rupture. For this reason, it’s critical to have the procedure done only when truly indicated and by the most experienced hands. If performed incorrectly or unnecessarily, the patient’s condition could worsen. We see cases where a subsequent adrenalectomy is not feasible due to significant damage to the adrenal glands during AVS. 

Importance of Seeking Expert Care 

Deciding whether AVS is necessary requires a careful evaluation of each patient’s specific condition. An expert in adrenal diseases, such as Dr. Carling, can help prevent unnecessary procedures and guide patients toward the best treatment options. Specialists in adrenal surgery and primary hyperaldosteronism are more likely to use a conservative approach to AVS, ensuring that it’s only done when necessary.  

Other doctors and patients often ask Dr. Carling a variation of the question: “Do you use AVS in primary hyperaldosteronism, routinely or rarely or ever or selectively?” Dr. Carling usually responds: “I use AVS in primary hyperaldosteronism, intelligently?”. This is not an attempt to be clever or smug. Rather, it displays a deep understanding of all the intricacies and subtleties that factor into making the best decision for each individual patient. This may include a recommendation for AVS, and it may not. In addition, sometimes the information from AVS is incomplete (especially failure to get accurate readings from the short right adrenal vein), but Dr. Carling can often use the data even from incomplete studies to give recommendations for further therapy. 

When You Should Seek AVS 

If the diagnosis is unclear, especially in older patients with negative or ambiguous imaging, or those with bilateral adrenal abnormalities, AVS becomes crucial in determining the correct treatment path. In these cases, skipping AVS could result in inappropriate treatment, either surgery or lifelong medication, neither of which may address the root cause effectively.

If adrenal vein sampling is determined to be needed, it will be performed in an interventional radiology (IR) suite similar to the one shown.

Real Patient Examples 

Example 1: When Adrenal Vein Sampling (AVS) is Needed 

Case: A 55-year-old woman, Sarah, presents with high blood pressure that has been difficult to control, despite being on multiple medications. She also has low potassium levels, which is a classic sign of primary hyperaldosteronism (Conn's syndrome). Other symptoms include sleep apnea and fatigue. Her blood tests show normal aldosterone levels, but a completely suppressed (low) renin. This proves primary hyperaldosteronism, but her imaging scans reveal nodules on both adrenal glands, making it unclear which gland is causing the issue. 

Why AVS is Needed: Because both adrenal glands show abnormalities on imaging, it’s crucial to determine which gland is responsible for the aldosterone overproduction. AVS can identify if one or both glands are overproducing the hormone, which will guide treatment. If one gland is the problem, surgery to remove the overproducing gland can cure her condition. If both glands are involved, either bilateral partial (function-preserving) adrenalectomy or medical management may be a better option. Without AVS, Sarah's treatment could be incorrect, potentially leading to unnecessary surgery or improper medication management​. 

Example 2: When Adrenal Vein Sampling is NOT Needed 

Case: A 34-year-old man, David, has been diagnosed with high blood pressure and normal potassium levels. After extensive testing, it’s clear from blood work (high aldosterone, and low renin, with an aldosterone renin ratio (ARR) greater than 100) and imaging that he has a unilateral aldosterone-producing adenoma (APA) on his left adrenal gland. David's symptoms (muscle cramps, fatigue, anxiety, frequent urination) and lab results strongly point to this adenoma as the cause of his primary hyperaldosteronism. 

Why AVS is NOT Needed: In David’s case, the imaging and lab results are so clear that AVS would not provide additional information. David is what we refer to as an “ALDO slam dunk”. His adenoma is visibly producing excess aldosterone, and surgery to remove the left adrenal gland is the straightforward solution. If David were told to undergo AVS, it would add unnecessary risk and expense to his treatment without changing the outcome​. 

Example 3: When Adrenal Vein Sampling (AVS) is Needed 

Case: A 45-year-old woman, Rebecca, presents with moderately high blood pressure. She is a very active triathlete and is confused and frustrated as to why she has developed blood pressure problems requiring medications. Her potassium levels are normal, but she is experiencing fatigue, excessive thirst, and muscle cramping, which are common in primary hyperaldosteronism (Conn's syndrome). Her blood tests show elevated aldosterone levels and suppressed (low) renin, but to her further confusion and frustration, her CT scan of the adrenal glands are reported as completely normal. There is no adrenal tumor on the scan. 

Why AVS is Needed: In patients with primary hyperaldosteronism (Conn's syndrome), where the scan (CT or MRI) show no tumor, it does not mean the patient does not have a tumor. YES! You can have a tumor that is so small it is not visualized on imaging. These patients should undergo AVS, since AVS can identify if one or both glands are overproducing the hormone, which will guide treatment. If one gland is the problem, surgery to remove the overproducing gland can cure her condition. If both glands are involved, medical management may be a better option. Without AVS, Rebecca’s treatment could be incorrect, potentially leading to improper medication management​, and the better surgical option is never explored.. 

Example 4: Unnecessary Adrenal Vein Sampling Avoided by Consulting an Expert 

Case: A 60-year-old woman, Patricia, was referred to undergo AVS after her general endocrinologist saw an abnormality on her adrenal gland on a CT scan. Although her blood pressure was elevated, her potassium levels were normal, and she didn’t have the typical symptoms of primary hyperaldosteronism. She sought a second opinion from Dr. Carling at the Carling Adrenal Center, and after careful review, primary hyperaldosteronism was ruled out.  

Outcome: After reviewing her case, Dr. Carling determined that Patricia did not need AVS. Her condition was not likely to be caused by primary hyperaldosteronism, and proceeding with AVS would have exposed her to unnecessary risks. Instead, her blood pressure was managed with medication, and she avoided a potentially harmful and unnecessary procedure. This case illustrates the importance of consulting with an adrenal expert who can provide a precise diagnosis and avoid unnecessary tests​. 

By seeking expert care from the start, Patricia avoided an invasive procedure and received the proper treatment for her condition. 

Conclusion 

Adrenal vein sampling is a valuable tool, but it is not needed for every patient. Seeking care from a high-volume adrenal specialist ensures that AVS is only performed when truly necessary, preventing potential risks and ensuring the best treatment outcomes.  

On this National Day of Radiology, we celebrate the role of radiologists like Dr. Karan Patel, who help ensure patients receive the care they need while avoiding unnecessary procedures. By the way, Dr. Carling’s younger brother is a famous interventional radiologist focusing on cancer treatments in Oslo, Norway. 

For more information, visit the Carling Adrenal Center and learn about how expert adrenal care can make all the difference in your diagnosis and treatment. 

Additional Resources: 

• Learn more about the Carling Adrenal Center
• Learn more about Dr. Tobias Carling
• Learn more about our sister surgeons at the Norman Parathyroid Center, Clayman Thyroid Center and Scarless Thyroid Surgery Center
• Learn more about the Hospital for Endocrine Surgery