Utility of Adrenal Vein Sampling With and Without Ultra-Low Dose ACTH Infusion in the Diagnostic Evaluation of Primary Aldosteronism.

BACKGROUND: Adrenal vein sampling (AVS), integral to identifying surgically remediable unilateral primary aldosteronism (PA), is technically challenging and subject to fluctuations in cortisol and aldosterone secretion. Intra-procedural adrenocorticotropic hormone (ACTH), conventionally administered as a 250-µg bolus and/or 50 µg per hour infusion, increases cortisol and aldosterone secretion and can improve AVS success, but may cause discordant lateralisation compared to unstimulated AVS. AIMS: To assess if AVS performed with ultra-low dose ACTH infusion causes discordant lateralisation. METHODS: Here, we describe our preliminary experience using an ultra-low dose ACTH infusion AVS protocol. We retrospectively reviewed the results of consecutive AVS procedures (n = 37) performed with and without ultra-low dose ACTH (1-µg bolus followed by 1.25 µg per hour infusion). RESULTS: Bilateral AV cannulation was successful in 70% of procedures pre-ACTH and 89% post-ACTH (p < 0.01). Sixty-nine percent of studies lateralised pre-ACTH and 55% post-ACTH, improving to 79% when both groups were combined. Lateralisation was discordant in 11 cases, including eight in which lateralisation was present only on basal sampling, and three in which lateralisation occurred only with ACTH stimulation. DISCUSSION: Overall, the decrease in lateralisation rates with ACTH was higher than previously reported for some protocols utilising conventional doses of ACTH. Our results suggest that AVS performed with ultra-low dose ACTH can cause discordant lateralisation similar to AVS performed with conventional doses of ACTH. CONCLUSION: Prospective studies directly comparing low and conventional dose ACTH AVS protocols and long-term patient outcomes are needed to help define the optimal ACTH dose for accurate PA subtyping.

Utility of semi-quantitative quick cortisol assay with low-dose adrenocorticotropic hormone infusion adrenal vein sampling.

BACKGROUND: Adrenal vein sampling (AVS) is integral to identifying surgically remediable unilateral primary aldosteronism (PA). However, right adrenal vein (AV) cannulation can be challenging, limiting its success. Intra-procedural cortisol assays can improve the reliability of AVS. The aim of this study was to validate the use of semi-quantitative cortisol estimates obtained utilizing a quick cortisol assay (QCA) during AVS procedures at our institution. METHODS: Retrospective review of results of AVS procedures before and after the introduction of the QCA. Twenty-three AVS procedures were performed with the provisional success determined by intra-procedural QCA. Successful AV cannulation was defined by an AV to peripheral vein cortisol ratio ≥ 4.0 (the selectivity index) from laboratory measurements. The control cohort consisted of 23 consecutive procedures prior to introduction of the QCA. RESULTS: QCA correctly predicted all AV cannulation attempts. Successful bilateral AV cannulation increased from 52% to 91% of procedures when performed with the QCA (P = 0.01) and adequate cannulation of the right AV increased from 61% to 91% (P = 0.03). There was no increase in procedural time, number of AV cannulation or sampling attempts. CONCLUSIONS: Point-of-care, semi-quantitative cortisol estimates can be performed accurately during AVS with QCA, facilitating improvements in AVS success rates without increasing procedural time.