Beyond the Lateralization Threshold: Outcomes in Primary Aldosteronism with Borderline Adrenal Vein Sampling Lateralization Index

Background: A lateralization index (LI) ≥4 on adrenal vein sampling (AVS) commonly distinguishes unilateral primary aldosteronism treated surgically from bilateral disease treated medically. Whether patients with LI Study Design: We performed a retrospective cohort study of patients with primary aldosteronism undergoing AVS from 2002–2022. Patients were classified as Classic Medical (CM; LI Results: Among 491 patients, NCS patients were younger and more frequently male than CS and CM patients. Baseline SBP and hypertension duration did not differ across groups. Adrenalectomy was associated with greater antihypertensive medication reduction (p Conclusions: In selected patients with primary aldosteronism and LI<4, adrenalectomy was associated with reduced antihypertensive medication burden compared with medical management. These findings support individualized surgical consideration beyond a strict LI≥4 threshold.