AVS is a common medical abbreviation representing several different concepts, which can lead to confusion. The most clinically significant meaning in advanced medicine is Adrenal Vein Sampling. This diagnostic procedure is typically performed in specialized medical centers to manage a specific hormonal disorder. This discussion will focus primarily on Adrenal Vein Sampling before outlining other medical applications of the AVS abbreviation.
The Primary Medical Meaning of AVS
Adrenal Vein Sampling (AVS) is a specialized, minimally invasive radiological procedure. It is used to diagnose the precise source of hormone overproduction in the adrenal glands, which are small organs situated atop the kidneys. AVS is the gold standard for subtyping Primary Aldosteronism (Conn’s syndrome), a common cause of secondary hypertension. The procedure involves an interventional radiologist threading a catheter into the adrenal veins to collect blood samples. By measuring aldosterone concentration, physicians determine if the excessive hormone is produced by one gland (unilateral) or both (bilateral), which dictates the treatment approach.
Why Adrenal Vein Sampling is Necessary
AVS is necessary because standard, non-invasive imaging techniques, such as CT or MRI, often fail to provide definitive information for treatment planning. Imaging can identify nodules but cannot confirm which gland is functionally overproducing aldosterone. AVS is the only reliable method to distinguish between unilateral disease (e.g., an aldosterone-producing adenoma) and bilateral adrenal hyperplasia. If AVS shows unilateral overproduction, the patient is a candidate for curative surgery, typically a laparoscopic adrenalectomy. If results show bilateral overproduction, the patient is managed with lifelong medication, such as mineralocorticoid receptor antagonists.
Understanding the Adrenal Vein Sampling Procedure
Preparation for AVS requires patients to discontinue or adjust certain medications, such as mineralocorticoid receptor antagonists and some blood pressure drugs, for several weeks. This adjustment prevents interference with hormone levels. Patients must also normalize their serum potassium level and maintain an unrestricted sodium intake. Most patients are instructed to fast for several hours prior to the procedure.
The procedure is usually performed on an outpatient basis by a skilled interventional radiologist. The patient receives a local anesthetic and light sedation. Access to the venous system is gained through a small puncture in the groin, where a catheter is inserted into the femoral vein.
Using continuous X-ray guidance (fluoroscopy), the radiologist navigates the catheter up to the adrenal veins. The right adrenal vein is technically challenging because it is short and drains directly into the inferior vena cava at a steep angle. A small amount of contrast dye is injected through the catheter to visualize the intricate anatomy of the veins on the X-ray images.
Many centers administer a continuous infusion of Cosyntropin (synthetic ACTH) during the procedure. This stimulates the adrenal glands and stabilizes hormone secretion, ensuring accurate comparison of aldosterone levels. Blood samples are collected from the left adrenal vein, the right adrenal vein, and a peripheral vein.
These samples are immediately sent for laboratory analysis to measure aldosterone and cortisol concentrations. The cortisol measurement acts as an internal control, confirming successful cannulation of the adrenal vein. After samples are drawn, the catheter is removed, and pressure is applied to the groin site. Patients are monitored for a few hours before being discharged, typically with instructions to rest for a day or two.
Other Important AVS Meanings in Medicine
While Adrenal Vein Sampling is the primary reference in endocrinology, the abbreviation AVS appears in other medical contexts.
Cardiology
In cardiology, AVS commonly stands for Aortic Valve Stenosis. This is a progressive heart condition where the aortic valve narrows, impeding blood flow from the heart. A less severe form is Aortic Valve Sclerosis, which represents early-stage thickening and stiffening of the valve leaflets.
Other Uses
Another use of the acronym is Arteriovenous Shunt, an abnormal connection between an artery and a vein. This connection can be congenital, develop due to trauma, or be created surgically for hemodialysis treatment. Finally, in patient care, AVS often stands for After Visit Summary, a document summarizing a patient’s visit findings, medications, and follow-up instructions.