Calculated Right Adrenal Vein Aldosterone Levels in Patients Undergoing Adrenal Vein Sampling: The Potential to Lateralize Despite Unsuccessful Selection of the Right Adrenal Vein.

PURPOSE

The aim of this study was to use calculated aldosterone level in the right adrenal vein (RAV) (cAldo) rather than measured level for identifying the dominant side of aldosterone secretion in patients with primary aldosteronism undergoing adrenocorticotropic hormone-stimulated adrenal venous sampling (AVS).

MATERIALS AND METHODS

Patients with primary aldosteronism who had successful AVS (selectivity index, >3) were studied. Based on the assumption that cortisol production from both adrenal glands is equal, aldosterone level in the RAV was calculated using the data from the left adrenal vein and inferior vena cava. The aldosterone level in the left adrenal vein (Aldo) compared with the cAldo (Aldo:cAldo ratio) was then used to determine the dominant side of aldosterone secretion compared with standard AVS interpretation using lateralization index (LI). LI ≥4 indicated unilateral disease, and LI ≤3 indicated bilateral disease. The LI between 3 and 4 was diagnosed as indeterminate.

RESULTS

Sixty-eight patients with concordant results between AVS and adrenal imaging study (32 were left-sided, 22 were right-sided, and 14 were bilateral) were selected for studying diagnostic performance. The Aldo:cAldo ratio with the cutoff values of ≥3 and ≤0.33 could identify unilateral diseases (left-sided and right-sided disease, respectively) with 92.6% sensitivity and 100% specificity.

CONCLUSIONS

The calculated Aldo:cAldo ratio can determine the dominant side of aldosterone secretion with high sensitivity and specificity when compared with standard AVS interpretation of measured levels. It provides an option for identification of unilateral and bilateral disease in select patients in whom right adrenal vein selection is unsuccessful.