FRI173 Investigation Of Cut Off Values For Identifying Cortisol Excess In Adrenal Venous Blood Sampling

Abstract Disclosure: K. Watanabe: None. K. Nakai: None. Y. Tsurutani: None. R. Hirose: None. J. Saito: None. T. Nishikawa: None. Objective: Primary aldosteronism (PA) is sometimes accompanied by subclinical Cushing’s syndrome (SCS). However, there is no defined cutoff value for excess cortisol (Cort) in adrenal venous blood sampling (AVS). Meanwhile, some reports have shown AVS usefulness in overt Cushing’s syndrome. This study analyzed AVS parameters to determine the cutoff value of excess Cort in AVS. Methods: The Cort-producing adenoma (CPA) group included patients with adrenal tumors who had a Cort level of ≥ 5 mg/dL after a 1 mg dexamethasone suppression test (DST) and underwent segmental AVS (sAVS) at our hospital from 2009-2020 (n = 75). Patients who underwent AVS on only one side had an adrenocorticotropic hormone (ACTH) level of > 10 pg/mL after 1 mg DST, a midnight Cort level of < 5.0 mg/dL, bilateral cortisol-producing tumors, and/or adrenal cancer, were excluded (n = 26). The control group with normal Cort secretion included patients with Cort level of < 1.8 mg/dL after 1 mg DST who underwent sAVS and whose resected adrenal tumor was negative or weakly positive in 11β-hydroxylase cytochrome P450 staining (n = 45). We compared the various sAVS values between the CPA and control groups. Results: Forty-nine patients in the CPA and 45 in the control groups were analyzed. Compared with the control, the CPA group had a significantly higher maximum Cort level in the tributary veins flowing from the tumor (1220 [860.1-1584.4] vs. 928 [695.5-1350.0], p = 0.016). Meanwhile, Cort levels in the central vein on the tumor side were not significantly different between the two groups (895 [614.7-1312.7] vs. 820 [590.5-1065.0], p = 0.202). The CPA group had a significantly lower minimum Cort level in all tributary veins (117 [73.1-241.5] vs 559 [386.0-794.0], p < 0.001), and Cort level in the central vein on the non-tumor side (176 [93.9-394.0] vs 766 [499.5-1090.0], p < 0.001). The ratio of each value showed that the maximum Cort level in tributary veins flowing from the tumor/minimum Cort level in all tributary veins (9.59 [3.75-21.23] vs 1.65 [1.45-2.06], p < 0.001) and Cort level in the central vein on the tumor side/Cort level in the central vein on the non-tumor side (4.44 [1.95-11.35] vs 1.04 [0.73-1.34], p < 0.001) were significantly higher in the CPA group. The former had the largest area under the curve for the receiver operating characteristic curve in various indices (AUC = 0.948, 81.6% sensitivity and 97.8% specificity when 3.28 was set as the cut-off value). Conclusion: Novel cutoff values were proposed to identify excess cortisol in AVS. Presentation: Friday, June 16, 2023