Interventional Diagnostics of Primary Hyperaldosteronism – Advocacy of an additional sampling site for incomplete adrenal venous sampling

Background: Adrenal venous sampling (AVS) is the gold standard for localizing aldosterone-producing adenomas in primary aldosteronism. However, unsuccessful cannulation of the right adrenal vein frequently results in inconclusive findings. This study evaluates the diagnostic utility of partial AVS data and the potential value of an additional sampling site. Methods: In this retrospective, single-institution diagnostic study, we analyzed all patients who underwent non-stimulated, bilaterally selective AVS for primary aldosteronism between November 2008 and January 2017. Univariable logistic regression was performed to assess the association between AVS measurements and lateralization. To simulate incomplete AVS data, missing values from the right adrenal vein were modeled, and multivariable analyses, including Receiver Operating Characteristic (ROC) curve analysis, were conducted to determine whether alternative sampling sites could improve diagnostic accuracy. Results: 59 patients were included: 16 with left-sided APA, 15 with right-sided APA, and 28 with idiopathic hyperaldosteronism. In multivariable multinomial logistic regression models, the aldosterone-to-cortisol ratio obtained from the suprarenal inferior vena cava (IVC) and the ratio derived from the left adrenal vein and infrarenal IVC were the strongest predictors of lateralization in cases with missing right adrenal vein data (p < 0.001). The predictive models achieved an area under the ROC curve (AUC) of 86% for identifying unilateral APAs. Conclusions: Alternative sampling sites, particularly the suprarenal IVC, can provide valuable diagnostic information when right adrenal vein cannulation is unsuccessful. These findings support a modified AVS protocol to improve diagnostic yield in patients with primary aldosteronism.