Session: SAT 53-73-Primary Aldosteronism & Mineralocorticoid Excess
Poster Board SAT-60
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 versus 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 (SI=3.0) and metanephrine (SI=10) in ACTH-stimulated AVS. Without stimulation, the concordance was 82% and 59% at respective cortisol-derived SIs of 2.0 and 3.0; AVS success rates determined by metanephrine (91%) were higher (P<0.01) than those determined by cortisol at an SI of 3.0 (56%), but not 2.0 (79%).
Conclusions: Metanephrine provides an alternative analyte to cortisol for sensitive assessment of AVS selectivity that appears particularly advantageous in sampling performed without ACTH stimulation.
Nothing to Disclose: JWML, TD, JD, LJS, DB, OV, ARMMH, MP, LR, GA, FCJS, SRB, HW, GE
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