Adrenal venous sampling (AVS) is the gold standard for distinguishing between unilateral aldosterone-producing adrenal adenomas and bilateral adrenal hyperplasia, and decision-making between unilateral adrenalectomy versus lifelong medical therapy. The difficulties in successful AVS, and the need for experienced personnel are generally acknowledged1. We audited the outcomes of AVS at our institution, and subsequent outcomes after modifying our AVS protocol. This aims to provide a real world review as to practical factors affecting success of AVS.
We reviewed the results of AVS from 15 consecutive patients between January 2013 to Nov 2016. Subsequent revisions in the protocol included ACTH stimulation (50ug/hr cosyntropin)1, simultaneous paired peripheral/adrenal sampling, CT mapping, greater rigour in protocol implementation, and testing of point-of-care cortisol assays. Results from a further 17 patients between Dec 2016 to Apr 2018 were subsequently analysed. Successful cannulation was defined as a selectivity index (adrenal cortisol/paired peripheral vein cortisol) of ≥ 2 (unstimulated) or ≥ 3 (ACTH stimulated). Lateralisation was defined as a Right:left (or vice versa) Aldosterone to cortisol ratio of ≥ 3 (without ACTH) or ≥ 4 (with ACTH).
Between 2013- Nov 2016, 7/15 (46%) AVS were successfully cannulated. Of these, 4 patients clearly lateralised (3.9 ±1.2, 16.1, 23.0, 43.6) but interpretation was not clear cut in the other cases due to high sample variability. Of 17 consecutive AVSs performed after Nov 2016, bilateral cannulation has been successful in 10 cases (59 %), even with the commencement of less experienced radiology personnel in transition plan. All cases which has been successfully cannulated have clearly distinguished between a unilateral vs bilateral source of hyperaldosteronism. The practicalities of the protocol will be discussed.
Ongoing local audit and rigorous implementation of AVS protocols are essential to improving the success in real world AVS for use in diagnosis and care.