FRI140 Impact Of Circadian Rhythm Of Aldosterone And Cortisol Levels Upon Adrenal Vein Sampling In Primary Aldosteronism

Disclosure: M. Kometani: None. M. Yoneda: None. K. Aiga: None. D. Aono: None. S. Karashima: None. Y. Takeda: None. T. Yoneda: None. Purpose: Adrenal venous sampling (AVS) is the gold standard technique for subtype differentiation of primary aldosteronism (PA). AVS is an invasive and challenging test; however, because of the high frequency of PA, it is currently performed at many institutions in Japan. Considering the effects of diurnal variations in the levels of aldosterone and cortisol, the guidelines recommends that AVS without ACTH loading should be performed in the morning. However, owing to staffing issues and general limitations, AVS is performed in the afternoon in many facilities. In this study, we examined the effects of AVS timing (AM/PM) on AVS results. Methods: This multicenter, retrospective, observational study included a total of 753 patients diagnosed with PA at four specialized institutions. The patients were divided into two groups according to the timing of the AVS procedure. The group classification of patients according to the time of the day when AVS was performed was not prospectively designed but rather determined based on feasible conditions at each facility. Among them, 504 and 249 patients underwent AVS in the morning (AM-AVS) and in the afternoon (PM-AVS), respectively. Results: The success rate of basal AVS in the AM-AVS group was 81% and that of ACTH-stimulated AVS was 92%. The success rate of basal AVS in the PM-AVS group was 74% and that of ACTH-stimulated AVS was 88%. There was no significant difference in the AVS success rate between the AM-AVS and PM-AVS groups. There was no significant difference between the AM-AVS and PM-AVS groups concerning the rate of unilateral diagnosis by AVS before ACTH stimulation, the rate of unilateral PA diagnosis by AVS after ACTH stimulation, and the percentage of cases with discrepancies between the two AVSs. Regarding patients with unilateral PA, aldosterone concentrations in adrenal venous blood did not differ between the two groups on the dominant or non-dominant side. Conversely, regarding patients with bilateral PA, aldosterone concentrations in adrenal venous blood were significantly higher in the AM-AVS than in the PM-AVS group. Conclusions: This study evaluated the effect of AVS timing. Although this was a multicenter study, there were no differences in the success rate of AVS, diagnostic rate of subtype, or frequency of deviation in the subtypes between the AM-AVS and PM-AVS groups. These results are relevant for facilities that can perform AVS only in the afternoon. Concerning aldosterone levels, no differences were observed between patients with unilateral lesions in the AM-AVS and PM-AVS groups, whereas its levels were different between patients with bilateral lesions in the AM-AVS and PM-AVS groups, suggesting the involvement of different mechanisms that regulate aldosterone secretion according to the circadian rhythm in patients with unilateral or bilateral lesions. Presentation: Friday, June 16, 2023