Clinical outcomes of primary aldosteronism based on lateralization index and contralateral suppression index after adrenal venous sampling in real-world practice: a retrospective cohort study

Background: We investigated whether the contralateral suppression index in aldosterone-producing adrenal adenoma could be used as a diagnostic criterion when catheterization in either right or left adrenal vein fails or when a discrepancy in the adrenal vein sampling (AVS) results and imaging findings occurs in the real-world practice. Methods: We retrospectively reviewed 48 patients who had resistant hypertension (HTN) or hypokalemia with a biochemical diagnosis of primary aldosteronism and who underwent AVS from January 2009 to June 2017 at a tertiary referral hospital. Selection index (SI), lateralization index (LI), and contralateral suppression index (CSI) were calculated based on AVS results and the final clinical outcomes were evaluated. Results: The catheterization of both adrenal veins was successful in 43 of 48 (89.6%) patients. The lateralization based only on LI was performed in 23 out of 43 (53.5%) patients. When CSI and LI were combined in decision making, the concordance between adrenal computed tomography scan and AVS for unilateral lesion improved from 59.3% (19/32) to 75.0% (24/32). CSI also correlated well with unilateral adrenal disease in the catheterization failure group. The final outcomes of HTN were better in the contralateral suppression group. Conclusion: CSI combined with LI could be a supplementary diagnostic tool in patients with non-lateralization or catheterization failure and predict the clinical outcomes of HTN in patients with primary aldosteronism.