Endocrine Abstracts

Introduction: In patients with primary aldosteronism (PA) international consensus claim that adrenal venous sampling (AVS) performs better than CT scan in determining lateralization of aldosterone secretion. The SPARTACUS study has however reported similar performances for lateralization by CT scan and AVS in patients with PA and a unilateral adrenal mass. The standard procedure for AVS uses cortisol values to validate the selectivity of catheterization and to normalize the aldosterone values before calculating lateralization index (LI). In this study we show that normalisation by cortisol in AVS can induce a wrong lateralization of aldosterone secretion in some patients with PA.

Objective: To analyze discordances between lateralization predicted by CT scan or by AVS in patients with PA and a unilateral adrenal mass.

Methods: Monocentric retrospective analysis of data of 33 selective AVS in patients with PA and a unilateral adrenal mass. AVS was performed simultaneously on both adrenal veins (AV) without stimulation and normalized with cortisol but also epinephrine. LI>4 was considered significant. Immunohistochemical analysis of CYP11B1, CYP11B2 and CYP17 was performed in the adrenal adenoma of one patient.

Results: One patient with severe hypertension and hypokalemia showed PA, no hypercortisolism and a 2 cm right adrenal mass. AVS was selective in both AV and cortisol-normalized AVS showed right/left LI = 0.8, ruling out lateralization, despite higher absolute values of aldosterone, but also cortisol, in the right AV. By contrast epinephrine-normalized AVS showed right/left LI = 6.25. The patient showed poor tolerance of anti-aldosterone treatment and eventually underwent right adrenalectomy, resulting in normalization of BP and remission of PA. Immunochemical analysis of the right adrenal adenoma showed expression of CYP11B2 but also CYP11B1 and CYP17, which allows to secrete both aldosterone and cortisol. Analysis of the 32 other patients identified five discordances between cortisol-normalized AVS lateralization and epinephrine-normalized AVS, with 2/5 patients showing concordance in epinephrine-normalized AVS and CT scan.

Conclusion: Cortisol-normalized AVS can fail to detect lateralization of aldosterone secretion by some Conn’s adenoma which secrete not only aldosterone but also cortisol. These adenoma are not necessarily detectable pre operatively as they may show a normal 1mg Dexamethasone test. They have recently been reported to be frequent and may represent one explanation for the good performances of CT scan in the SPARTACUS study. We propose that AVS aldosterone values be normalized on epinephrine or on any product secreted by the adrenal gland, but not by the adenoma.