Laterality Diagnosis of Adrenal Vein Sampling for Primary Aldosteronism Using Aldosterone Alone

Background: In adrenal vein sampling (AVS) for primary aldosteronism (PA), cortisol concentration is used to determine successful AVS, and laterality diagnosis is performed using a combination of aldosterone and cortisol concentrations. In this study, we examined the comparison with the conventional method when AVS was determined by aldosterone alone. Subjects and methods: We studied the data from 277 patients with PA who underwent AVS in Sapporo City General Hospital from July 2007 to April 2020. The patients with autonomous cortisol production were excluded. Using the blood samples from adrenal veins and inferior vena cava (IVC) after ACTH stimulation, the predicting ability of the left and right ratio of aldosterone concentration (aldosterone ratio, AR) for lateralization Index (LI) was examined by Receiver operating characteristic (ROC) analysis. The predicting abilities of the ratio of aldosterone concentration between adrenal vein and IVC (aldosterone index, AI) and aldosterone concentration for selectivity index (SI) and contralateral ratio (CR) were also examined by ROC analysis. Results: Six samples (0.01%) with SI <5 after ACTH stimulation those were determined unsuccessful AVS. The results of the area under the curve (AUC) in ROC analysis of aldosterone concentration and AI for prediction of SI>5 was 0.998, 0.990, respectively, p=0.39. The optimal cut-off values of aldosterone concentration and AI for prediction successful AVS were 1700 pg/ml (sensitivity 99.5%, specificity 100%), 7.44 (sensitivity 94.0%, specificity 100%), respectively. Seventy-two patients (27.3%) had LI >4 who were diagnosed as unilateral aldosterone excess. AR had 0.94 of AUC for prediction of LR >4. The optimal cut-off value of AR was 3.53 (sensitivity 86.1%, specificity 94.8%). Eighty-two patients (31.1%) had unilateral CR<1. The AUC of aldosterone concentration and AI for prediction of CR<1 was 0.96, 0.98, respectively, p=0.07. The optimal cut-off values of aldosterone concentration and AI were 13600 pg/ml, 42, respectively. The sensitivity and the specificity at the optimal cut-off points of aldosterone concentration and AI were 91.5%, 91.5% and 91.5%, 94.8%, respectively. Conclusions: The determination of successful AVS and unilateral result in AVS can be predicted using aldosterone alone. It was suggested that AR is useful for tentative interpretation in the cases where the results of aldosterone were previously reported and lateralizing diagnosis of the cases with autonomous cortisol production.