Effect of Intraprocedural Cortisol Measurement on ACTH-stimulated Adrenal Vein Sampling in Primary Aldosteronism

CONTEXT: Adrenocorticotropin (ACTH) loading is used to increase the success rate of adrenal vein sampling (AVS). OBJECTIVE: We aimed to determine the effect of intraprocedural cortisol measurement (ICM) on ACTH-stimulated AVS (AS-AVS) owing to a lack of reliable data on this topic. METHODS: This multicenter, retrospective, observational study took place in 28 tertiary centers in Japan. Among 4057 patients enrolled, 2396 received both basal AVS (B-AVS) and AS-AVS and were divided into 2 groups according to whether ICM was used. The effect of ICM on AS-AVS was measured. RESULTS: In patients who underwent both AVS procedures, the ICM group had significantly higher success rates for both B-AVS and AS-AVS than the non-ICM group did. However, the probability of failure of AS-AVS after a successful B-AVS and the probability of success of AS-AVS after a failed B-AVS were not significantly different in the 2 groups. For subtype diagnosis, propensity-score matching revealed no significant difference between the 2 groups, and the discrepancy rate between B-AVS and AS-AVS for subtype diagnosis was also not significantly different. CONCLUSION: ICM significantly increased the success rate of B-AVS and AS-AVS in protocols in which both AVS procedures were performed and had no effect on subtype diagnosis. However, in protocols in which both AVS procedures were performed, the results suggest ICM may not be necessary when performing AS-AVS if ICM is used only when B-AVS is performed. Our study suggests that ICM during AVS plays an important role and should be recommended.