Enhancing adrenal vein sampling: the role of plasma metanephrines in diagnosing primary aldosteronism

Zin Htut; Ali Alsafi; Aditi Sharma; Daniel Foran; Tricia Tan; Sophie C Barnes; Emma L Williams; Debbie Papadopoulou; Aimee Dimarco; Fausto Palazzo; Jeannie Todd; Rami Fikri; Karim Meeran; Florian Wernig

doi:10.1530/endoabs.109.OP3.3

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Endocrine Abstracts (2025) 109 OP3.3 | DOI: 10.1530/endoabs.109.OP3.3

SFEBES2025 Poster Oral Presentations Adrenal and Cardiovascular (4 abstracts)

Enhancing adrenal vein sampling: the role of plasma metanephrines in diagnosing primary aldosteronism

Zin Htut ¹ , Ali Alsafi ² , Aditi Sharma ² , Daniel Foran ^3,2 , Tricia Tan ^1,2 , Sophie C Barnes ⁴ , Emma L Williams ² , Debbie Papadopoulou ² , Aimee Dimarco ^2,1 , Fausto Palazzo ^1,2 , Jeannie Todd ^1,2 , Rami Fikri ⁵ , Karim Meeran ^1,2 & Florian Wernig ^1,2

Author affiliations

¹Imperial College London, London, United Kingdom; ²Imperial College Healthcare NHS Trust, London, United Kingdom; ³University of Oxford, Oxford, United Kingdom; ⁴North West London Pathology, London, United Kingdom; ⁵University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom

Introduction: Adrenal vein sampling (AVS) is the gold standard for diagnosing primary aldosteronism (PA) subtypes, but cortisol’s long half-life and potential co-secretion complicate its use. Plasma metanephrines (MN), with a shorter half-life and a higher adrenal vein (AV) to peripheral vein (PV) gradient, may provide a more reliable alternative.

Method: We retrospectively analysed 131 AVS procedures (January 2018-May 2023) in patients with confirmed PA. Receiver operating characteristic (ROC) curve analyses were used to assess the utility of plasma MN using established aldosterone-to-cortisol (AC) ratios as reference criteria. Cannulation success was defined by an AV/PV cortisol ratio >2, while unilateral disease was indicated by an AV/AV AC ratio >2 with contralateral suppression <0.5 of the PV.

Results: ROC analysis revealed an optimal MN selectivity index (SI) of >3, achieving 99% sensitivity, 100% specificity, and an area under the curve (AUC) of 1.0. Successful cannulation was confirmed in 126 patients using both MN and cortisol SIs. To establish a MN lateralisation index (LI), we excluded 9 patients who did not have contralateral suppression. ROC analysis of the remaining 117 identified an optimal AM LI cut-off of >4, yielding 93% sensitivity, 95% specificity, and an AUC of 0.95, indicating unilateral disease in those confirmed by AC criteria (AC LI >2, AC CSI <0.5). Concordant results were observed in 94% of cases. Among 14 patients with cortisol co-secretion, 5 had discordant AVS results, including 1 additional patient with a post-dexamethasone cortisol level of 36 nmol/l. Four of these five patients underwent adrenalectomy, confirming adenomas, while one opted for medical therapy. All surgically treated patients achieved complete remission.

Conclusion: While not the first study to describe this approach, our findings support that incorporating aldosterone/metanephrines improves diagnostic accuracy in primary aldosteronism with cortisol co-secretion, enhancing clinical decision-making and potentially improving patients’ outcomes.