Adrenal Vein Sampling to Distinguish Between Unilateral and Bilateral Primary Hyperaldosteronism: To ACTH Stimulate or Not?

The aim of this study is to determine the accuracy of adrenal vein sampling (AVS) with and without adrenocorticotropic hormone (ACTH) stimulation to distinguish between unilateral and bilateral primary hyperaldosteronism (PA). Retrospective analysis of a prospective database from a referral center between 1984 and 2009, 76 patients had simultaneous cannulation of bilateral adrenal veins and AVS with and without ACTH stimulation. All patients had adrenalectomies. The selectivity index (SI, cut-off value >= 2) was used for confirmation of successful cannulation of the adrenal vein. The lateralization index (LI, cut-off value >2 and >4) was used for distinguishing between unilateral and bilateral PA. The SI ratio was higher with ACTH stimulation compared to without for the right adrenal vein (p = 0.027). The LI > 2 ratio was higher with ACTH stimulation compared to without (p = 0.007). For the LI > 4 ratio, there was no difference between with and without ACTH stimulation (p = 0.239). However, for a LI > 4, 7 patients (9.2%) were not lateralized with ACTH stimulation, but they did lateralize without ACTH stimulation. AVS with ACTH stimulation is associated with a higher SI ratio compared to AVS without ACTH stimulation. However, when using LI > 4 for AVS, samples without ACTH stimulation should also be included to detect a subset of patients with unilateral disease that are not detected with ACTH stimulation.