LAUSR

OBJECTIVE Adrenal vein sampling (AVS) and CT often show confusingly discordant lateralization results in primary aldosteronism (PA). We tested a biochemical algorithm using AVS data to detect cortisol co-secretion as a potential explanation for discordant cases. DESIGN Retrospective analysis from a large PA + AVS database. PATIENTS All patients with PA and AVS, 2005-2020. MEASUREMENTS An algorithm using biochemical data from paired AVS + CT images was devised from physiological first principles and informed by data from unilateral, AVS-CT concordant patients. The algorithm involved calculations based upon the expectation that low cortisol levels exist in adrenal vein effluent opposite an aldosterone-and-cortisol-producing adrenal mass and may reverse lateralization due to inflated aldosterone/cortisol ratios. MAIN OUTCOMES The algorithm was applied to cases with discordant CT-AVS lateralization to determine whether this might be a common or explanatory finding. Clinical and biochemical characteristics of identified cases were collected via chart review and compared to CT-AVS concordant cases to detect evidence of biological plausibility for cortisol co-secretion. RESULTS From a total of 588 AVS cases, 141 AVS + CT pairs were clear unilateral PA cases, used to develop the 3-step algorithm for AVS interpretation. Applied to 88 AVS + CT discordant pairs, the algorithm suggested possible cortisol co-secretion in 40%. Case review showed that the proposed cortisol co-secretors, as identified by the algorithm, had low/suppressed ACTH levels, larger average nodule size, and lower plasma aldosterone. CONCLUSIONS Pending external validation and outcome verification by surgery and tissue immunohistochemistry, cortisol co-secretion from aldosteronomas may be a common explanation for discordant CT-AVS results in PA. This article is protected by copyright. All rights reserved.