Poster Presentation ESA-SRB 2023 in conjunction with ENSA

Accuracy of point of care rapid cortisol assay to predict success of adrenal vein sampling: a real-world prospective audit of the use of a rapid cortisol assay with 50mcg/hr ACTH-infusion in a tertiary referral hospital. (#268)

Tsui Yue Ong 1 , Tavleen Kaur 1 , Hong Lin Evelyn Tan 1 2 , Michelle Kerr 1 , Shamasunder Acharya 1 2 , Richard Ruddell 3 , Christian Abel 4 , Michael Carey 4 , Christine O'Neill 2 5 6 , Emma E Croker 1 2
  1. Department of Endocrinology, John Hunter Hospital, New Lambton, NSW, Australia
  2. School of Medicine and Public Health, University of Newcastle, Newcastle, NSW, Australia
  3. Department of Anatomical Pathology, John Hunter Hospital, Newcastle, NSW, Australia
  4. Department of Medical Imaging, John Hunter Hospital, Newcastle, NSW, Australia
  5. Department of Surgery, John Hunter Hospital, Newcastle, NSW, Australia
  6. Hunter Medical Research Institute, Newcastle, NSW, Australia

Adrenal vein sampling(AVS) is the gold standard to lateralise surgically-curable primary aldosteronism(1). Point-of-care semi-quantitative rapid cortisol assay(RCA) has been shown to increase rate of successful adrenal vein cannulation in this technically challenging procedure(2-4). There is limited published prospective data on accuracy of RCA with continuous intravenous(IV)  cosyntropin(ACTH)-infusion.

Aim: Assessment of accuracy of RCA (AVS Accuracy Kit) in predicting successful cannulation during AVS with ACTH-infusion.

Methods: Prospective data was collected November 2021 to August 2023 from AVS procedures performed via sequential cannulation with continuous IV ACTH-infusion (50mcg/hr). RCA was used to predict cannulation success. RCA was inspected visually at 2 and 5 minutes. Appearance of test line indicated likely unsuccessful cannulation and procedure adjusted accordingly. Successful AVS was defined as selectivity index (SI)≥5.0 (adrenal vein cortisol:peripheral vein cortisol).

Results: Thirty-two consecutive AVS were performed with overall success rate 78% (n=25). 108 RCA were used (average 3.4/procedure). 59% (n=19) of procedures were adjusted based on RCA predicting failed cannulation. Of these, 63% (n=12) were subsequently successful. Selectivity index, cortisol levels and 2X2 contingency table are shown in table 1. Absence of RCA test line had 100% positive predictive value for successful cannulation. Presence of RCA test line had 95% negative predictive value, indicating cannulation was highly unlikely. In the 2 cases of inaccurate RCA result (2/108), a very faint line appeared at 5 minutes (adrenal venous cortisol 5004/5352/nmol/L with peripheral cortisol 901/714nmol/L) with final SI ≥5. Slight catheter adjustment was made, with subsequent samples successful with no adverse outcome. 

Conclusion: The semi-quantitative RCA can confidently be used to predict successful cannulation in AVS with ACTH-infusion. The procedure should be adjusted in the presence of a definite test line. Radiologist discretion is advised when a very faint test line on RCA is detected.

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