Diagnostic Utility of Plasma Metanephrine in Adrenal Venous Sampling for Subtyping of Primary Aldosteronism
Rakesh Garg, Manasvini Bhatt, Devasenathipathy Kandasamy, Shipra Agarwal, Ashutosh K. Arya, Sarah Alam, Rajesh KhadgawatAbstract
Introduction:
Primary aldosteronism (PA) is the most common endocrine cause of secondary hypertension and is associated with elevated cardiovascular and renal risks independent of blood pressure levels. Adrenal venous sampling (AVS) remains the gold standard for PA subtyping; however, cortisol-based normalisation can be confounded by autonomous cortisol secretion, thereby affecting diagnostic accuracy. This study investigates the utility of plasma metanephrine compared to cortisol during AVS in patients with PA.
Methods:
This was a retrospective analysis of 35 patients with biochemically confirmed PA who underwent AVS. Plasma cortisol and metanephrine were simultaneously measured to assess selectivity and lateralisation.
Results:
Among 35 patients, 20 underwent unstimulated AVS and 15 underwent stimulated AVS. Bilateral successful cannulation was achieved in 91.4% of patients when a metanephrine-based selectivity index (SI) was used, compared with 74.28% with a cortisol-based SI. In 92.3% of patients, the lateralisation results were consistent with both cortisol- and metanephrine-based indices. Ten patients underwent unilateral adrenalectomy; in all cases, histopathological analyses confirmed the presence of
Conclusion:
Plasma metanephrine outperforms serum cortisol for determining successful catheterisation during AVS. Unstimulated AVS, using either biomarker, achieves procedural success comparable to stimulated AVS but with higher lateralisation rates. These findings support the use of plasma metanephrine and unstimulated protocols to enhance diagnostic accuracy in PA.