8562 Mineralocorticoid Receptor Antagonist Do Not Prevent Primary Aldosteronism Subtyping by Adrenal Vein Sampling

Abstract Disclosure: G. Pintus: None. T.M. Seccia: None. G. Rossitto: None. B. Caroccia: None. G. Ceolotto: None. L. Lenzini: None. G. Rossi: None. Background. Current guidelines suggest withdrawal of mineralocorticoid receptor antagonists (MRA) before subtyping primary aldosteronism (PA) by adrenal venous sampling (AVS), but this practice can cause severe hypokalemia and/or uncontrolled high blood pressure (BP) values. Aims. To investigate the feasibility of unilateral PA (uPA) identification by AVS in patients on MRA treatment. Methods. We compared the rate of uPA identification between patients with and without MRA treatment, using two large datasets of patients who were submitted to AVS from 2000 to 2023 in absence of interfering drugs. The rate of uPA identification was also compared between patients with suppressed renin levels (DRC < 2 mUI/L) and unsuppressed renin levels (DRC > 2 mUI/L or DRC > 8.2 mUI/L). Results. Compared to non-MRA PA patients (n = 779), those with MRA (n = 61) showed a higher daily drug dose (2.25 vs 1.5, p = 0.001), a higher rate of adrenal nodules at imaging (82 vs 67, p = 0.022) and of adrenalectomy (72 vs 54%, p = 0.01). The AUROC of lateralization index (LI) did not show significant differences between groups, neither under unstimulated conditions (0.960 vs 0.937, p = 0.590) nor after cosyntropin (0.923 vs 0.917, p = 0.938). Sensitivity analyses confirmed these results 1) after propensity score matching in several adjusted models and 2) in patients with undetectable, suppressed or unsuppressed renin levels. Conclusions. MRAs, at doses that controlled blood pressure and potassium levels in PA patients, did not preclude the identification of uPA at AVS. Moreover, unsuppressed renin levels were not associated with lower rate of uPA identification. Presentation: 6/3/2024