The Utility of Plasma Metanephrines to Optimise Adrenal Vein Sampling for Primary Aldosteronism: A Single Centre Experience

Abstract

Background

Primary aldosteronism (PA) is a prevalent yet frequently underdiagnosed cause of secondary hypertension, affecting up to 10% of hypertensive individuals and contributing to increased cardiovascular risk. Accurate diagnosis is vital, as unilateral PA cases typically require surgical intervention, while bilateral disease is managed medically. Adrenal vein sampling (AVS) remains the gold standard for diagnosing subtypes of PA; however, the use of cortisol to confirm accuracy of cannulation poses challenges due to its long half-life and potential cortisol co-secretion by aldosterone-producing adenomas.

Objective

This study evaluates the diagnostic utility of plasma metanephrines (MN) as an alternative to cortisol in assessing cannulation success and lateralisation of aldosterone secretion.

Methods

Analysing 132 unstimulated AVS procedures performed by a single operator on 129 patients with confirmed PA, we established optimal cut-off values for the selectivity index (SI) and lateralisation index (LI) using MN.

Results

A MN SI cut-off of >3 achieved 99% sensitivity and 100% specificity, while an aldosterone/MN LI of >4 indicated unilateral disease with 94% sensitivity and 96% specificity.

Conclusion

Our findings demonstrate that incorporating MN measurements significantly enhances the accuracy of AVS interpretations, particularly in cases of cortisol co-secretion, thereby minimising diagnostic errors and optimising treatment strategies. This study supports the use of MN as reliable analytes to improve the diagnostic accuracy of AVS.