SAT-LB41 Surgery Outcomes for Patients With Primary Aldosteronism Who Show Normal-Appearing Adrenals on Computed Tomography but Unilateral Disease on Adrenal Venous Sampling

Background: The primary aldosteronism (PA) subtype is usually confirmed by computed tomography (CT) and adrenal venous sampling (AVS). However, the subtype diagnosis by AVS is not necessarily consistent with the subtype diagnosis by CT. Patients with PA who show normal-appearing adrenals on CT but unilateral disease on AVS (CT-negative and AVS-unilateral group) are often found. However, few studies have focused on them, despite a discrepancy between CT and AVS subtype diagnosis. Objective: The aim of this study was to evaluate the clinical features of CT-negative and AVS-unilateral group and assess whether they obtain benefits from surgery. Methods: We retrospectively analyzed 362 consecutive patients with PA who underwent both CT and adrenocorticotropic hormone (ACTH)-unstimulated AVS at Kanazawa University Hospital. First, the patients were divided into normal-appearing adrenals, bilateral adrenal nodules, or unilateral adrenal nodules based on CT findings. Second, they were classified as having unilateral or bilateral disease based on ACTH-unstimulated AVS. The criterion for successful selective catheterization was selectivity index >2 and unilateral aldosterone overproduction was confirmed by lateralized index ≥2. Among the group with normal appearing-adrenals on CT, we examined preoperative clinical characteristics between those with unilateral disease on AVS and those with bilateral disease on AVS. In addition, we compared surgical outcomes of CT-negative and AVS-unilateral group with those of CT-unilateral and AVS-ipsilateral group (patients with unilateral lesions on CT and ipsilateral disease on AVS). The Surgical outcomes for unilateral PA were evaluated according to the criteria of the Primary Aldosteronism Surgical Outcome study. Results: The success rate of AVS in patients with normal-appearing adrenals on CT was 88% (167/190). Furthermore, the discordance rate between CT and AVS in patients with normal-appearing adrenals on CT was 36% (60/167). There were no significant differences in preoperative clinical characteristics between the CT-negative and AVS-unilateral group (n=60) and the CT-negative and AVS-bilateral group (n=107). After surgery, the CT-negative and AVS-unilateral group (n=14) had a lower complete biochemical success rate than the CT-unilateral and AVS-ipsilateral group (n=30) (43% vs. 80%, p=0.02), but clinical and biochemical benefits (the complete and partial success combined) were not significantly different between them (71% vs. 93% (p=0.07) and 71% vs. 90% (p=0.13), respectively). Conclusion: The clinical features of CT-negative and AVS-unilateral group were significantly similar to those of CT-negative and AVS-bilateral group. They benefited from surgery, and AVS should be performed for patients who pursue surgical management when the CT findings suggest normal-appearing adrenals.