In this episode, host Dr. Aparna Baheti interviews Dr. Fritz Angle about adrenal vein sampling, including indications, workup, and his technique for accessing the right adrenal vein.
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SHOW NOTES
Dr. Fritz Angle is the Director of Interventional Radiology at the University of Virginia. He frequently performs adrenal vein sampling for primary hyperaldosteronism, and has developed a specific technique. The patient is usually referred from an endocrinologist or primary care doctor. The IR should review the labs to verify the aldosterone-to-renin ratio is greater than 20. Additionally, it is important to review medications and stop all potassium sparing diuretics at least two weeks before the procedure. If they haven’t had a CT scan, the IR should order one to assess the position of the right adrenal vein, the hardest to access due to its variable anatomy.
The morning of the procedure, Dr. Angle always checks a potassium level to know whether to give potassium supplements. He gets dual femoral access, so that he can obtain both non-stimulated and ACTH-stimulated samples. He obtains the sample from the left adrenal vein first. For the right side, he starts with a C2 catheter, to which he adds side holes using a biopsy needle. The left adrenal vein is almost always one vertebral body above the right renal vein, so he begins here, with the catheter pointing directly posterior. He searches around the entire back wall of the IVC by puffing contrast and rotating the catheter. He moves up and down by half a vertebral level. If he still cannot locate it, he begins looking to the left and right. When injecting, it is important to be gentle. To do this, he inserts an 014 wire through his catheter, then does a dry scan to see if the vein is pointing toward the liver or the right adrenal gland. If the vein is injected too hard, it can cause a venous infarct and adrenal insufficiency. The right adrenal vein forms an upside down Y shape. Dr. Angle draws two sets each from the right and left adrenal veins and two peripheral samples.
To interpret results, look for a cortisol of 2-3x greater (3-4x greater in stimulated samples) compared to the peripheral blood to confirm correct placement in the adrenal veins. Once you correct aldosterone levels to cortisol levels, the aldosterone-to-cortisol ratio should be about 5x greater on one side (compared to the other side) to confirm the diagnosis and lateralize the hyperaldosteronism to one side. About 2 ⁄ 3 cases lateralize, but Dr. Angle has found many patients’ symptoms are actually due to bilateral adrenal hyperplasia. Finally, Dr. Angle emphasizes that this is an easy, safe procedure that all IRs should offer.
