MON-290 Effects of Hypokalemia on Adrenal Vein Sampling in the Evaluation of Primary Hyperaldosteronism

Abstract Disclosure: S. Dotson: None. B.D. Anawalt: None. R.R. Narla: None. T.S. Tylee: None. Background: Hypokalemia suppresses serum aldosterone concentrations, even in patients with primary hyperaldosteronism. Although guidelines recommend correcting hypokalemia before adrenal venous sampling (AVS), the effect of hypokalemia (or its correction) impact on lateralization is unclear. We hypothesized that the effect of hypokalemia on lateralization would be minimal during AVS sampling done during continuous cosyntropin infusion. Methods: We retrospectively analyzed 102 consecutive patients who underwent AVS for hyperaldosteronism between 2017 and 2024. Patients had a serum potassium level measured immediately prior to AVS; only one patient received potassium supplementation based on these results. We compared lateralization rates between those with potassium ≤3.5 meq/L (low K) and those with >3.5 meq/L (nl K) to assess the impact of hypokalemia on lateralization. Results: Of the 102 patients who underwent AVS, 58 (57%) lateralized and 44 (43%) did not. Among the 60 low K patients, 37 (62%) lateralized, while 23 (38%) did not. In contrast, 21 of 42 nl K patients (50%) lateralized. Of the 60 patients with low K, 31(51.7%) underwent adrenalectomy, compared to 17 of the 42 (40.5%) patients with nl K who underwent adrenalectomy. For the 48 patients that underwent adrenalectomy, the post-adrenalectomy pathology revealed adrenal cortical adenomas in 34 patients (71%), while 14 patients (29%) had other pathologies, including adrenal cortical adenoma with background hyperplasia, multifocal hyperplasia, or adrenal micronodules. Of the 31 low K patients that underwent adrenalectomy, 21 had adrenal cortical adenomas, 9 had adenomas with hyperplasia, and 1 had multifocal hyperplasia. Among the 16 nl K patients, 13 had adrenal cortical adenomas, 1 had adenoma with hyperplasia, 1 had micronodules, and 1 had multifocal hyperplasia. In low K patients, blood pressure meds decreased from 3.1 to 1.7 (-1.4) post-adrenalectomy. In nl K patients, it decreased from 3.4 to 2.0 (-1.4). Summary: Hypokalemia is common on the day of AVS and if lateralization occurs hypokalemia does not decrease the likelihood of clinical benefit from an adrenalectomy.Hypokalemia is more common with aldosterone-producing adenomas and complex adrenal pathology.Lateralization, regardless of the potassium, predicts a reduction in blood pressure medications required after adrenalectomy.Hypokalemia on the day of AVS does not indicate a greater reduction in blood pressure medications post adrenalectomy compared to normal potassium. Conclusion: Hypokalemia immediately prior to AVS does not seem to affect lateralization rates and AVS can proceed with mild hypokalemia. Patients with hypokalemia immediately prior to AVS are more likely to have an aldosterone-producing adenoma. If lateralization occurs, patients are likely to have a similar reduction in blood pressure medications whether they have hypokalemia or not. Presentation: Monday, July 14, 2025