Are catecholamine-derived indexes in adrenal venous sampling useful for judging selectivity and laterality in patients with primary aldosteronism?

In order to investigate retrospectively whether catecholamine concentrations obtained by adrenal venous sampling (AVS) are useful for lateralization of the aldosteronoma-bearing adrenal gland. The study population comprised 35 patients (10 men, 25 women; mean age, 49.8 years) with aldosteronoma and 18 patients (9 men, 9 women; mean age, 51.8 years) with non-functioning adenoma who underwent AVS between 1994 and 2010. In all cases, AVS was performed without administering adrenocorticotrophic hormone. Successful or unsuccessful adrenal vein blood sampling (selectivity) was judged by the ratio of plasma cortisol (C) level in each adrenal vein to that in the infra-renal inferior vena cava [C(side)/C(IVC)] as a gold standard, with successful selectivity defined using four different cut-off values [C(side)/C(IVC) ≥ 3.0, 2.0, 1.36 or 1.1]. Receiver operating characteristics (ROC) analyses were conducted to determine: (1) degree of selectivity; and (2) the best catecholamine (epinephrine, norepinephrine, and dopamine)-derived index for lateralization of the aldosteronoma-bearing adrenal gland. Among the catecholamine-derived indexes, the epinephrine concentration ratio of adrenal vein to IVC was the most reliable for all four different cut-off values in the evaluation of adrenal vein selectivity. Meanwhile, the ratio of aldosterone to norepinephrine between dominant and non-dominant sides was the most reliable index (right: area under the curve (AUC), 0.965 ± 0.024; 95 % confidence interval (CI), 0.874-0.996; left: AUC, 0.937 ± 0.033; 95 % CI, 0.834-0.985) for lateralization of the aldosteronoma-bearing gland. Catecholamine concentrations obtained by AVS are useful for not only judging selectivity, but also lateralization of the aldosteronoma-bearing gland.