Primary aldosteronism caused by unilateral adrenal disease can be identified by adrenal vein sampling (AVS) and treated by adrenalectomy1. A recent study suggested that patients whose resected adrenal tissue contains a CYP11B2 (aldosterone synthase) staining adenoma (classical pathology) are more likely to be cured than those whose resected adrenal contains micronodules (non-classical pathology)2. We have reported that AVS outcomes before and after the use of ACTH stimulation can be discordant (median lateralisation index ≥ 4 pre-ACTH to <4 post-ACTH), with the loss of lateralisation post-ACTH affecting 18% of patients3. We hypothesise that AVS discordance may predict both adrenal histopathology and surgical outcomes.
We performed a retrospective analysis of AVS results, histopathology, and surgical outcomes in 41 patients who underwent AVS and adrenalectomy at Monash Health between 2009-2020.
Of the 32 patients with concordant lateralisation on AVS both pre- and post-ACTH, 9 demonstrated classical pathology, 6 had non-classical pathology and 11 had mixed pathology. 6 did not stain for CYP11B2. 18 patients achieved complete biochemical cure with a normalised aldosterone renin ratio at 3 – 12 months post-surgery, while 8 patients had missing post-operative data. Of the 9 patients with discordant lateralisation on AVS, none had pure classic pathology while 1 had non-classical and 7 had mixed pathology. Among this group, from 5 patients with post-operative biochemical data, 4 achieved complete cure while 1 had partial cure with persistently abnormal aldosterone to renin ratio.
In summary, patients with concordant results pre- and post-ACTH stimulated AVS are more likely to display a CYP11B2 positive adenoma and achieve complete surgical cure. Conversely, patients with AVS discordance are more likely to display non-classical or mixed pathology and lower rates of clinical cure. Hence, ACTH stimulation may be a valuable tool in AVS to identify “falsely lateralising” PA and decrease the risk of unsuccessful surgery.