Postoperative ACTH-stimulated aldosterone predicts biochemical outcome in primary aldosteronism.

Abstract

Primary aldosteronism (PA) is the most common surgically curable cause of hypertension. Unilateral aldosterone-producing adenoma can be treated with adrenalectomy. Clinical and biochemical outcomes are assessed 6-12 months after adrenalectomy according to PASO consensus criteria. Earlier prediction of biochemical remission would be desirable as it could reduce cumbersome follow-up visits. We hypothesized that postoperative ACTH stimulated plasma aldosterone concentrations (PAC) measured shortly after adrenalectomy can predict PASO outcomes. Retrospective cohort study. We analyzed 100 patients of the German Conn's registry who underwent ADX and postoperative ACTH stimulation tests within the first week after adrenalectomy. 6-12 months after adrenelectomy we assessed clinical and biochemical outcomes according to PASO criteria. Serum cortisol and PAC were measured by immunoassay at baseline and 30 min after the intravenous ACTH infusion. We used receiver operating characteristics (ROC) curve analysis and matched the parameters to PASO outcomes. 81% of patients had complete, 13% partial and 6% absent biochemical remission. Complete clinical remission was observed in 28%. For a cut-off of 58.5pg/ml, stimulated PAC could predict partial/absent biochemical remission with a high sensitivity (95%) and reasonable specificity (74%). Stimulated PAC's area under the curve (AUC) (0.89; CI 0.82-0.96) was significantly higher than other investigated parameters. Low postoperative ACTH stimulated PAC was predictive of biochemical remission. If confirmed, this approach could reduce follow-up visits to assess biochemical outcome.