We obtained informed consent in all patients.
Adrenal vein sampling was performed in 37 patients with primary aldosteronism (32 men,
5 women; mean age: 60,4 years; minimum age: 40 years; maximum age: 74 years.
(Figure 3)
The diagnosis of primary hyperaldosteronism was clinical and biochemical.
CT,
MRI and adrenal venous sampling were used to identify its etiology (CT and MRI protocols are shown in Figure 4).
CT and MRI were used to rule out malignant causes (Figure 5) and to obtain anatomical information of the adrenal glands (anatomical variants,
adrenal vein,
etc).
(Figure 6).
Adrenal vein sampling was only performed in patients with primary aldosteronism preceded by adrenal CT/MR to exclude a malignant cause.
All patients with suspected primary hyperaldosteronism were subjected to a three-step diagnostic algorithm.
(Figure 7).
Adrenal vein sampling is essential when considering surgery even if the patient has a CT/MRI with a unilateral macronodule.
Adrenal vein sampling was performed after the modification of the antihypertensive therapy according to the guidelines of the endocrinology society.
(Figure 8).
Before the procedure we administered intravenous synthetic ACTH (250 mcg of ACTH in 500 ml of 0.9% saline,
100 ml/hour from 30 minutes before the test) to minimize fluctuations in aldosterone secretion induced by stress during the non-simultaneous procedure,
to maximize the cortisol gradient of the adrenal vein with respect to the inferior vena cava and confirm the correct sampling of the adrenal vein and to maximize the aldosterone secretion of an aldosterone-producing adenoma.
We performed the procedure with the patient monitored,
in conscious sedation (Midazolam and Fentanyl) and local anaesthesia (Mepivacaine 2%) is applied at the puncture site.
Puncture of the right common femoral vein was performed and cannulated with a long introducer 6F Super Arrow-Flex (ARROW) of 35 cm that allows direct extraction of the sample from the inferior caudal cava to the renal veins.
(Figure 9)
Through the right common femoral vein,
adrenal vein sampling was performed not simultaneously: the operator started each procedure obtaining at least 5 mL first in the right adrenal vein,
then in the inferior vena cava and finally in the left adrenal vein for measurements of cortisol and aldosterone.
For cannulation of the right suprarenal vein,
Cobra1 4F Optitorque catheter (TERUMO) was often used.
While Simmons 2 (TERUMO) or Simmons 3 (CORDIS) both of 5F,
were used for the left suprarenal vein.
When the vein was not localized we used the midpoint of the gland as a theoretical position.
(Figure 10).
Then,
the selectivity index and the laterality index were calculated.
The right and left selectivity index was calculated as the ratio between the cortisol levels of each adrenal vein with the inferior vena cava.
Sampling was considered correct if the selectivity indexes were > 5.
The laterality index was calculated as the relationship between aldosterone on the dominant and non-dominant sides.
Lateralization was considered if the lateralization index was ≥ 4,
negative if <3 and indeterminate between 3 and 4.