Role of adrenal vein sampling in primary aldosteronism: the Monash Health experience

BACKGROUND: Adrenal vein sampling (AVS) is useful for distinguishing unilateral versus bilateral hypersecretion in primary aldosteronism (PA), but is technically challenging. Furthermore, the use of adrenocorticotropic hormone (ACTH)-stimulation in AVS is controversial. We implemented a Monash Health-specific AVS protocol in 2010. AIM: The audit aimed to: (i) examine the impact of a dedicated protocol on success rates of AVS at a tertiary referral centre; (ii) evaluate the impact of AVS on sub-typing of PA; and (iii) assess the utility of ACTH stimulation in AVS. METHODS: AVS was performed on patients with PA confirmed by positive saline suppression testing (aldosterone level >140 pmol/L post-saline infusion), with sequential sampling of adrenal and peripheral veins, pre- and post-ACTH infusion. Patients with unilateral aldosterone-producing adenoma diagnosed on successful AVS were referred for adrenalectomy. RESULTS: Between 2010 and 2014 inclusive, a total of 28 AVS procedures was performed, with complete pre- and post-ACTH data for 19 procedures. Bilateral successful cannulation rates improved post-implementation of our protocol (61% vs 41%). Of the patients, 32% had discordant imaging and AVS results: four patients with unilateral adenomas did not lateralise on AVS and were managed medically; four patients with bilateral or no adenomas on imaging, lateralised on AVS and had surgery. Overall, use of ACTH did not increase successful cannulation and tended to mask lateralisation. CONCLUSION: AVS is crucial in subtype classification of PA and should be performed by a dedicated radiologist with a standardised protocol. AVS outcomes were not improved with the use of ACTH stimulation.