Introduction to Adrenal Vein Sampling
Adrenal vein sampling is performed by an interventional radiologist in an interventional radiology (IR) suite. These types of doctors are radiologists with special training in using X-rays and performing procedures with tiny catheters.
Adrenal vein sampling is an X-ray study to figure out:
a) Does the patient have too much aldosterone production from one or both adrenal glands? b) Which adrenal gland harbors the tumor, the left or right?
Adrenal vein sampling is an interventional radiology study performed by radiologists trained specifically in performing invasive procedures using catheters. Adrenal vein sampling is recognized by Endocrine Society (U.S.) guidelines as the only reliable way to correctly diagnose the subtypes of primary hyperaldosteronism. Adrenal vein sampling is needed when the adrenal CT scan does not show a tumor (the tumor is too small to be detected on a CT or MRI scan) or in patients who have adrenal tumors on both the right and the left side. Through small catheters, blood samples are obtained from each adrenal vein and the inferior vena cava. In experienced centers, the bilateral adrenal veins are catheterized and sampled with a technical success rate exceeding 90%. The technical success rate of adrenal vein sampling is directly related to the operator experience. This is a test you want to travel for.
Remember, not all patients need to have adrenal vein sampling. Dr. Carling, Editorial note: Again, if you have primary hyperaldosteronism, let us review your scan (CT or MRI). We have more experience scrutinizing adrenal tumors on CT scans (and have published widely about it) than any endocrinologist or radiologist (X-ray) doctor. We have seen it all. We have published extensive scientific studies, proving which patients need and do not need adrenal vein sampling. Let us review all your information, and help you make the best decision if you need adrenal vein sampling, or not.
Again, technical success of adrenal vein sampling is directly associated with operator experience. You want the best possible interventional radiologist to perform your adrenal vein sampling. The Carling Adrenal Center in Tampa has the world’s best IR doctor and team to perform adrenal vein sampling. A positive adrenal vein sampling enables curative adrenal surgery for primary hyperaldosteronism (Conn’s syndrome).
Experience matters! You need the most experienced interventional radiologist to perform your adrenal vein sampling
Similar to adrenal surgery, performing adrenal vein sampling is both an art and science. There is a very strong correlation between the expertise and experience of the interventional radiologist and the results of adrenal vein sampling. The most expert centers for adrenal vein sampling have a technical success rate exceeding 90%. An expert interventional radiologist has a much higher success rate, lower complication rates and can perform the procedure much faster than somebody who is not an expert. There are very few experts performing adrenal vein sampling in the United States, less than a dozen. If you have primary hyperaldosteronism, it is definitely worth traveling to an expert center for your adrenal vein sampling. Every week we see cases where the patient has had an adrenal vein sampling performed erroneously and the results become meaningless. Even worse, we sometimes see patients who have suffered major complications with bleeding, hematomas, and rupture of the adrenal veins. You do want to travel for your adrenal vein sampling. It is very unlikely that your local hospital has any expertise in performing adrenal vein sampling. In fact, the experience at most major Ivy League university hospitals is not good enough. Fortunately, at the Carling Adrenal Center in Tampa, we have the best interventional radiology team to perform adrenal vein sampling.
The best adrenal operation for primary hyperaldosteronism is the Mini Back Scope Adrenalectomy (MBSA). Read more about the MBSA surgery here Mini-Back-Scope-Surgery.
Some, but not all, patients with primary hyperaldosteronism (Conn’s Syndrome) need adrenal vein sampling
Not all patients with primary hyperaldosteronism need adrenal vein sampling. Patients who are young, have an obvious tumor on the CT scan, and with a completely normal adrenal gland on the other side, do not need the study. They can go straight to curative adrenalectomy and skip this step. Similarly, patients who respond very well to spironolactone and similar drugs and have very high aldosterone levels almost never need adrenal vein sampling. They can go straight to adrenal surgery. What do I do if I am unsure if I need adrenal vein sampling, or not? After you have had your CT scan of your adrenal glands, you can contact the Carling Adrenal Center and will be happy to evaluate your case and your CT scan and determine whether or not you need adrenal vein sampling. If you need to have the procedure, we can perform both the adrenal vein sampling and the surgery during the same visit. We are the only center in the world that can provide this service.
Having a specific adrenal-protocol pre-procedure CT scan prior to adrenal vein sampling improves the results and success rate
A special pre-procedure adrenal CT scan protocol developed by Dr. Carling and his radiology colleagues clearly identifies the right adrenal vein (arrow) draining into the inferior vena cava (IVC)
It is very important to have a specific adrenal-protocol CT scan prior to adrenal vein sampling since it improves the technical success rate dramatically. The reason for this is that the CT scan gives very detailed anatomical information about the tiny adrenal veins, specifically the right adrenal vein. The CT scan guides the interventional radiologist during the procedure and allows him to accurately identify the tiny vessels. Dr. Carling and his radiology colleagues at the Carling Adrenal Center have developed a very specific pre-procedure CT scan protocol that dramatically improves the success rate of adrenal vein sampling. If your center does not offer an adrenal protocol pre-procedure CT scan in preparation of your adrenal vein sampling, chances are the success rate is very low and you should consider going elsewhere.
Do not let your doctor just treat you with blood pressure pills because he or she cannot find a center to perform adrenal vein sampling
IMPORTANT. Every single week, we talk to patients that have been told that they will have to be treated with blood pressure pills for their primary hyperaldosteronism for the rest of their lives. Their doctor does not know what to do next, or how to find someone to perform adrenal vein sampling. The doctor has given up. They settle for treating the patient just with blood pressure pills. This is terrible medicine. The path of least resistance is often treating the patient with blood pressure pills. This is terrible advice. Patients with primary hyperaldosteronism (even when the high blood pressure is treated) have a more than 1,000% increased risk of heart attacks, strokes, and heart arrhythmias. Patients die prematurely from primary hyperaldosteronism. Putting patients on pills for primary hyperaldosteronism does not fix the problem. The problem is the tumor producing toxic levels of aldosterone. Even if your CT scan shows tumors on both adrenals, or if the CT scan shows no tumor at all, do not let your doctors just treat you with pills. You need adrenal vein sampling.
The risks of adrenal vein sampling are low, but not zero
Adrenal vein sampling is not without risks. This is an invasive procedure. Again, the risk of complication is directly related to the experience and mastery of the interventional radiologist. The most common risks with the procedure are bleeding causing a hematoma, adrenal infarction, adrenal vein thrombosis and perforation (or rupture) of the adrenal vein. At the Carling Adrenal Center, we use very small amounts of contrast dye injection and have an extremely favorable safety profile. In fact, we have never had bleeding or injury to the adrenal veins during this procedure. But because there are some (although very low in our hands) risks associated with the procedure, it is important that adrenal vein sampling is performed only in patients who truly need it. This is where the expertise of an adrenal surgeon and the team is very important to identify the patients that truly benefit from the procedure.
Typical results from a positive adrenal vein sampling demonstrate an aldosterone-producing adrenal tumor in the left adrenal gland. The adrenal vein sampling results need to be interpreted by an expert. The aldosterone levels are corrected for the cortisol concentration (A/C ratio). This patient had a 17-minute Mini Back Scope Adrenalectomy (MBSA) and was completely cured of her Conn’s syndrome. She came off all her blood pressure medications and all potassium pills.
Adrenal surgery still can be the best option even if the adrenal vein sampling demonstrates that there is no obvious tumor on one of the adrenal glands
In the ideal scenario the adrenal vein sampling demonstrates significantly higher aldosterone production from one of the two adrenal glands. This makes surgery and adrenalectomy curative in nature. If there is overproduction of aldosterone from both adrenal glands, surgery still may be a very favorable option as opposed to just treating the patient with blood pressure pills for life. There is emerging data that the combination of adrenal surgery and maximal medical therapy is better than just treating the patient with blood pressure medications. Surgery not only improves the blood pressure and potassium levels, but liberates the patients of debilitating symptoms, and improves the quality of life. Surgery can be particularly helpful in patients who are on several blood pressure medications, respond poorly to blood pressure medication or have developed resistance to blood pressure medications. Sometimes performing bilateral partial adrenalectomy may be the best option. The goal is to remove the aldosterone overproducing part of the adrenals, but leave enough normal adrenal cortex where the patients does not need to take cortisol supplementation (usually hydrocortisone).
Read more about the partial adrenal surgery here partial-cortical-sparing-adrenalectomy.
An allergy to contrast dye is a contraindication to adrenal vein sampling
Adrenal vein sampling is very safe. However, some patients have an allergy to intravenous iodinated contrast dye. This is the same contrast dye used in CT scans. Severe reactions to iodinated contrast media is very rare (about 1/10,000 or 0.01%). Sometimes patients can be pre-treated with steroids, and antihistamines if they have had previous problems with contrast media. However, if you have had a serious reaction (swelling, erythema, low blood pressure, anaphylactic shock, raising heart rate, and wheezing) to contrast media, avoiding adrenal vein sampling may be the best option. In this case, it is preferable to let the CT scan (without contrast) guide the plan for adrenalectomy instead of adrenal vein sampling.What are the top 10 Things to Know About Adrenal Vein Sampling for Primary Hyperaldosteronism (Conn's Syndrome)? Read more on our adrenal surgery blog