Low-grade Cortisol Cosecretion Has Limited Impact on ACTH-stimulated AVS Parameters in Primary Aldosteronism

Context: In primary aldosteronism, cosecretion of cortisol may alter cortisol-derived adrenal venous sampling indices. Objective: To identify whether cortisol cosecretion in primary aldosteronism alters adrenal venous sampling parameters and interpretation. Design: Retrospective case-control study Setting: A tertiary referral center Patients: 144 adult patients with primary aldosteronism who had undergone both adrenocorticotropic hormone-stimulated adrenal venous sampling and dexamethasone suppression testing between 2004 and 2018. Main Outcome Measures: Adrenal venous sampling indices including adrenal vein aldosterone/cortisol ratios and the selectivity, lateralization, and contralateral suppression indices. Results: 21 (14.6%) patients had evidence of cortisol cosecretion (defined as a failure to suppress cortisol to <= 50 nmol/L post dexamethasone). Patients with evidence of cortisol cosecretion had a higher inferior vena cava cortisol concentration (P= .01) than those without. No difference was observed between the groups in terms of selectivity index, lateralization index, lateralization of aldosterone excess, or adrenal vein cannulation rate. Conclusions: Cortisol cosecretion alters some parameters in adrenocorticotrophic hormone-stimulated adrenal venous sampling but does not result in alterations in patient management.