Endocrine Abstracts

Purpose: Adrenal vein sampling (AVS) is the gold standard method for subtyping primary aldosteronism (PA). A certain number of PA patients had unilateral successful AVS, concomitant autonomous cortisol secretion or indeterminate lateralization index (LI 2.5–4), which made correct interpretation of AVS data impossible. The aim of our study was to determine whether absolute aldosterone concentration can predict the subtype of PA in patients with inconclusive AVS data.

Methods: A retrospective single-institution analysis of 60 PA patients was performed at University Hospital Centre Zagreb between 2015 and 2020. Unilateral successful AVS, autonomous cortisol secretion or patients with AVS LI 2.5–4 were excluded from the study. We calculated the cut-off value of absolute aldosterone concentration predicting healthy or unilaterally diseased glands with optimal sensitivity and specificity. ROC curve analysis was performed with P<0.01.

Results: The optimal absolute aldosterone cut-off value predicting a healthy gland was ≤ 12974 pmol/l (sensitivity 82.4%, specificity 87.2%). When we set the specificity to 91% (sensitivity 74%), the aldosterone cut-off value was ≤ 9243. On the other hand, the optimal absolute aldosterone cut-off value predicting a unilaterally diseased gland was > 44250 pmol/l (sensitivity 64.7%, specificity 80.8%). Setting the specificity at 90.4% (sensitivity 32.3%) the aldosterone cut-off value was > 66000 pmol/l.

Conclusions: Our data showed that absolute aldosterone concentration could be helpful to predict the subtype of PA in a subset of patients with inconclusive AVS data.