Context: More reliable parameters than cortisol are needed for assessing correct catheter positioning during adrenal vein sampling (AVS). Plasma metanephrine represents one such alternative.
Objective: To determine the utility of adrenal venous (AV) plasma concentrations of metanephrine to establish correct catheter positioning during AVS.
Design and methods: We included 86 AVS procedures: 52 ACTH-stimulated and 34 non-stimulated sequential procedures. Plasma cortisol, metanephrine, normetanephrine, epinephrine and norepinephrine concentrations were measured in AV and peripheral venous (PV) samples. AVS success rates, according to cortisol AV:PV selectivity indices of 2.0 and 3.0, were compared with that for metanephrine using a selectivity index (SI) determined by ROC curve analysis.
Results: Among AVS procedures assessed as selective using a cortisol SI of 3.0, the median AV:PV plasma metanephrine ratio was 6-fold higher than that for cortisol (94.0 vs 15.5, P<0.0001). There were significant positive relationships between AV:PV ratios for cortisol and metanephrine for ACTH-stimulated samplings, but not for non-stimulated samplings. ROC curve analysis indicated a plasma metanephrine SI cut-off of 10. There was 96% concordance in AVS success rates determined by cortisol and metanephrine derived SIs in ACTH-stimulated AVS. Without stimulation, the concordance was 82 and 56% for at respective SIs of 2.0 and 3.0; AVS success rates determined by metanephrine (91%) were higher than those determined by cortisol (56 and 79% for respective SIs of 3.0 and 2.0).
Conclusions: Metanephrine provides an alternative analyte to cortisol for sensitive assessment of AVS selectivity that appears particularly advantageous in sampling performed without ACTH stimulation.
27 Apr - 01 May 2013
European Society of Endocrinology