Dados do Trabalho

Título

Comparison of metanephrine and cortisol to assess selectivity and lateralization of adrenal vein sampling in primary aldosteronism

Introdução

Adrenal vein sampling (AVS) is the gold standard approach to define lateralization of aldosterone (A) secretion in primary aldosteronism (PA). However, AVS is a challenging procedure. Cortisol (C) level in adrenal veins (AV) and inferior vena cava (IVC) is used to determine successful catheterization and to normalize A level. Cosyntropin stimulation in AVS significantly increases the recognition of successful cannulation of AV. Moreover, cortisol co-secretion may affect the interpretation of AVS. Few studies demonstrated a high accuracy of plasma metanephrine (MN) to define AVS successful catheterization and lateralization.

Objetivo

In this study, we aimed to compare the usefulness of MN and C to assess AVS selectivity and lateralization in PA patients with or without cortisol co-secretion.

Método

We prospectively evaluated 15 patients with confirmed diagnosis of PA that underwent AVS. Sequential AVS under cosyntropin continuous infusion was performed by an experienced interventional radiologist. C, A and MN were measured in AV and IVC samples. Successful catheterization was defined by a selectivity index ≥5 [SI= C or MN concentrations in AV/IVC]. Unilateral aldosterone secretion was defined by a lateralization index ≥4 [LI= A/C or A/MN ratio in the dominant AV divided by A/C or A/MN in the non-dominant AV].

Resultados

Among 15 patients with PA, 60% were male and the median age at diagnosis was 56 years old (range, 38 to 73). The median age at the diagnosis of hypertension was 32 years of old (17 to 45). Hypokalemia was evidenced in 57% of the cases. Cortisol co-secretion was diagnosed in 4 out of 14 PA patients (28.5%). SI using MN was 4.4 (1.2 to 22.7) and 3.5 (1.1 to 10) higher than SI using C in the right and left side, respectively (p = 0.002 for the right and p < 0.001 for the left side). The catheterization success rate was 86.6% (13 out of 15) with MN and 80% (12 out of 15) with cortisol. LI using MN was significantly correlated with LI using C (r= 0.866, p < 0.001). AVS lateralization (LI >4) was identified in 54% (7 out of 13) of the cases using C and in 46% (6 out of 13) of the cases using MN. The only discordant case lateralized to the right AV using C and was bilateral using MN. Among the cases with cortisol co-secretion, AVS result was concordant in all cases using C or MN.

Conclusão

In conclusion, MN had a very high correlation with C to define AVS selectivity and lateralization. Therefore, MN is very useful for AVS analysis, specially in the absence of ACTH stimulation.