Endocrine Abstracts

Adrenal vein sampling (AVS) is the gold standard for detecting aldosterone production in bilateral adrenal hyperplasia and for distinguishing the lateralization of aldosterone secretion. Successful AVS is determined by calculating the selectivity index (SI). The cut off value for the SI is ≥2.0 under un-stimulated conditions. The aldosterone level (AL) is corrected for cortisol level (CL) and adjusted values are then compared to determine the lateralizing index (LI). Most centres use LI between 2.0 and 4.0. LI ≥4 is compatible with a unilateral source of aldosterone. Contralateral gland suppression can also confirm the diagnosis. There is also an increase in the detection of synchronous excretion of aldosterone and cortisol from adrenal masses. AVS is not routinely used in the diagnostic workup of adrenal hypercortisolism. AV: IVC cortisol ratio and the gradient can be used to differentiate unilateral from bilateral cortisol overproduction. Young et al. suggested the cortisol gradient of AV to PV or IVC greater than 6.5. Predominant cortisol secretion was considered if the cortisol lateralization ratio was ≥ 2.3. We present a series of 10 cases with biochemically functional bilateral adenomas. Seven patients had successful cannulation and two had difficulty in cannulating right side, one result was equivocal. Five had hyperaldosteronism. Two had hypercortisolemia. One of these patients had synchronous excretion of aldosterone and cortisol. 8 patients had adrenalectomy. The histology showed discrete adenoma in five cases and hyperplasia in 3. 1 case with difficult cannulation of right adrenal vein had adrenalectomy, with removal of adrenal gland that had larger adenoma. All patients have been cured. Our analysis show AVS is a useful tool in expert hands to accurately diagnose and lateralise the hyperaldosteronism, hypercortisolemia and synchronous excretion of aldosterone and cortisol accompanied by bilateral adrenal masses. It can help to provide guidance to the treatment.