ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2013) 32 P8 | DOI: 10.1530/endoabs.32.P8

Plasma metanephrine for assessing the selectivity of adrenal venous sampling

Tanja Dekkers1, Jaap Deinum1, Leo Schultze Kool1, Dirk Blondin2, Oliver Vonend2, Ad Hermus1, Mirko Peitzsch3, Lars Rump2, Gerald Antoch2, Fred Sweep1, Jacques Lenders1,3, Stefan Bornstein3, Holger Willenberg2,3 & Graeme Eisenhofer3

1Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands; 2University Medical Center Düsseldorf, Dusseldorf, Germany; 3University Hospital Carl Gustav Carus, Dresden, Germany.

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.