Left-right differences in adrenal vein sampling for primary aldosteronism

In adrenal venous sampling (AVS) for patients with primary aldosteronism (PA), adrenocorticotropic hormone (ACTH) stimulation generally increased the success rate. The effect of ACTH stimulation on the left-right differences of laterality diagnosis in AVS remains unclear. A total of 167 patients with PA underwent successful AVS were examined. Patients with autonomous cortisol secretion were excluded. The proportion of dominant side in AVS was compared before and after ACTH stimulation. Unilateral disease on AVS was defined as a lateralization index of more than 4, both before and after ACTH stimulation. Before ACTH stimulation, unilateral disease was more frequently observed on the right side than the left side (right 33.5% vs. left 13.8%, p < 0.01). After ACTH stimulation, unilateral disease was more frequently observed on the left side than the right side, without statistical significance (left 15.6% vs. right 10.8%, p = 0.20). Among the 56 patients who had right unilateral disease before ACTH stimulation, 17 patients (30.0%) also had right unilateral disease after ACTH stimulation. The affected side of AVS was changed from right unilateral to bilateral after ACTH stimulation in 34 (60.7%) out of 56 patients. These patients had milder PA and CT scans showed no nodular lesions on the right side. In AVS, ACTH stimulation not only decreased unilateral results but also shifted to the dominant side. Overestimation should be carefully considered when the surgical indication for the right adrenal gland was decided based on AVS results without ACTH stimulation.