Adrenal venous sampling

I had today what I thought was going to be the decisive meeting with my nephrologist: the CT scan from a week and a half ago showed a small (1 cm) adenoma on the left adrenal gland. I feared that the next step would be surgery, but no, there is another test that can be performed before this final step.

Incidentally, I praised the doctor for his approach to the problem: although there have been many steps, there has been a gradual progression from a minor, no inconvenience, test (blood), through a slightly more complicated test (urine collection with salt loading) followed by a more complicated, but still non-invasive test, the CT. Now the gloves are coming off: the next step is invasive as is (of course) the final step. Here is a very good web site that explains the various steps in the diagnosis, so to be fair, the doctor was following their advice.

So what is the next stage? Adrenal venous sampling. There's a somewhat learned web page that discusses this, but an easier explanation can be found here. In simple terms, even though there is an adenoma on the left adrenal gland, it may not be producing aldosterone (which is upsetting the balance). The way to test this is to compare blood taken from the left adrenal gland to that taken from the right adrenal gland; if both samples have the same aldosterone level, then the adenoma is non-producing and can be left as it is. But should the sample from the left gland have a higher aldosterone level, then ....

Here's a nice picture of what's going to happen. For the patient, it's similar to catherisation, where a catheter is inserted into the femoral vein and then travels up to the heart. In this case (AVS), the catheter doesn't have to travel far, and in the words of the nephrologist, it's a much easier procedure as there's no need to battle with the blood pressure found in the aorta.