SUN-233 Prevalence and Outcome of Persistent Renin Suppression after Unilateral Adrenalectomy in Patients with Primary Aldosteronism

Abstract Disclosure: I. Stüfchen: None. J. R.O.L. Schweizer: None. F. Völter: None. S. Zopp: None. P. Zimmermann: None. T. Williams: None. M. Reincke: None. Background: Suppressed plasma renin concentrations (PRC) in medically treated patients with primary aldosteronism (PA) are associated with a worse cardiometabolic outcome. Consequently, normalization of PRC is a criterion for biochemical response to medical therapy. This study investigates the prevalence and outcome of persistent renin suppression after adrenalectomy in patients with unilateral PA. Methods: We included 77 patients that underwent adrenalectomy for PA and evaluated postoperative renin recovery. Patients were divided into tertials based on their renin concentration approximately six months after adrenalectomy (first follow-up). We compared histopathology using CYP11B2 staining according to histopathology of primary aldosteronism consensus (HISTALDO), biochemical and clinical outcomes according to the Primary Aldosteronism Surgical Outcome (PASO) criteria and improvement of comorbidities and end-organ damage at short- and long-term follow-up ranging from six months to three years postoperatively. Results: Renin concentrations were <8mU/l, between 8 and 16mU/l, or >16mU/l at first follow-up in the respective groups. Patients with renin concentrations <8mU/l had twice as often non-classical histopathology (multiple aldosterone-producing nodules, aldosterone-producing micronodules and aldosterone-producing diffuse hyperplasia) as the other two groups together (8/26 (30.8%) vs. 1/25 (4%) vs. 3/26 (11.5%); p=0.024) and less frequently complete biochemical remission at their first follow-up, defined by the normalization of aldosterone-to-renin ratio and correction of hypokalemia (p<0.01). Clinical outcome assessed by improvement in arterial hypertension and reduction in antihypertensive drugs, long-term biochemical outcome, and improvement in end-organ damage and comorbidities did not differ in between the three groups. Conclusions: In our study, suppressed renin concentrations <8mU/l occurred in approximately 30% of PA patients six months after adrenalectomy. Despite a worse short-term biochemical outcome, long-term biochemical and clinical outcomes, including comorbidities and end-organ damage, do not appear to be associated with postoperative renin concentrations. Presentation: Sunday, July 13, 2025