The overall goal of this interventional radiological examination is to precisely detect the location of macro and micronodules associated with adrenal diseases. The main advantage to a super-selective adrenal venous sampling, or ssAVS, for short, is that it can detect a tiny mass of aldosterone producing adenoma. We first had the idea for this method when we realized the conventional catheter could sometimes be inserted into a small tributary vein.
So we introduced the use of a microcatheter. Inserting this new type of catheter deeper into tributary veins is very difficult. So, the procedure is best explained by visual demonstration.
Set up the patient on an examination bed. First, attach an intravenous line in the upper arm or left leg for drug administration. Then, clean the skin at the location for blood sample.
Anesthetize the patient locally. Once anesthetized, disinfect the skin over the right femoral vein, and then insert an access sheath to perform adrenal venous sampling. Now, collect fine images using digital subtraction angiography.
Gently flush iopromide diluted in saline into the tissue via the microcatheter. And then, collect images. Place the tip of the parent catheter into left adrenal at the appropriate angle and depth.
The accuracy of the placement is essential for the delivery of the microcatheter. Now, slowly collect blood sample to collect the concentrations of plasma aldosterone and plasma cortisol. Repeat this process for the left central adrenal vein, the left renal vein, the right vein, the IVC and the right central adrenal vein.
The right adrenal vein can be sampled just like the left except the adrenal R catheter is used instead of an adrenal L catheter. After taking all of the blood samples, inject an initial bolus of 200 micrograms of a synthetic adrenocorticotropic hormone, cosyntropin, through the venous line. 30 minutes after the initial bolus of cosyntropin, start the continuous cosyntropin feed.
15 minutes after the initial bolus of cosyntropin, collect blood samples from the adrenal vein. First, use a conventional technique. Then, use the described super-selective technique.
Next, using angiography, direct the catheter tip into one of the tributary veins. Prevent the patient from breathing too deeply, or the vertical angle may change. Then, insert a saline-filled microcatheter with a guide wire.
Perform venography gently through the microcatheter with flushing a small amount of saline diluted contrast medium, then collect a blood sample. Now, direct the parent catheter tip at the next tributary vein and take another blood sample. Repeat this process for each tributary vein.
Follow the adrenal venous sampling, collect a blood sample from the left common vein and right femoral vein. Now, remove the catheter and access sheath. Then, compress and bandage the two access points and immediately proceed with the blood analysis.
A 46-year-old PA diagnosed female presented with symptoms. She had been treated with an adrenalectomy 13 years prior, however, an abdominal CT scan revealed a 22 millimeter tumor in a right adrenal vein. A venography showed the tumor extended into the lateral tributary vein, suggested a large volume of blood was flowing out from the adenoma.
Using the super-selective sampling, blood was collected from the lateral tributary vein after confirmation by a venography. The microcatheter was then inserted into the superior and inferior tributary veins for additional blood samples. Analysis revealed that the plasma aldosterone concentration, or PAC, was high in both the central vein and the lateral tributary vein, however PAC levels were normal in the superior and inferior tributary veins.
Cortisol or PCC were similar in each vessel, suggesting uniform cortisol production. The patient then underwent a partial adrenalectomy and the pathology confirmed the diagnosis. Aldosterone synthase expressed in many cells and steroid 11-beta-hydroxylase expressed in a small number of cells.
In the adjacent normal adrenal, aldosterone synthase was not expressed in the zona glomerulosa but steroid 11-beta-hydroxylase was expressed normally, suggesting that cortisol production was normal. Thus, the pathology was indeed consistent with the super-selective sampling and after performing the surgery, the patient's blood pressure normalized without the use of antihypertensive drugs. When attempting this procedure, it is very important to insert the microcatheter perfectly.
Once mastered, this technique can be performed in about 90 minutes. Since its development, this technique has improved the diagnosis and treatment of hypertension in primary aldosteronism. In fact, the research of the ssAVS test always consistent with the pathology of surgical specimens using ol-ten-oh-eez or steroidogenic enzymes.
