Endocrine Abstracts

Background: Low plasma aldosterone after adrenalectomy due to aldosterone-producing adenoma (APA) and postoperative hypoaldosteronism recovery have been well described. However, prospective time course comparing simultaneously aldosterone and renin levels is still lacking.

Aim: We prospectively studied clinical and biochemical findings emphasizing aldosterone and renin levels, in a cohort of patients with APA who underwent adrenalectomy in a single tertiary center.

Patients and Methods: Of 38 patients diagnosed with primary aldosteronism (PA) from 2016-2019, eighteen patients were diagnosed with APA (11M,7F)and underwent unilateral adrenalectomy. Among them, five were excluded by lost or short follow up, kidney disease, cortisol co-secretion, and aldosterone secreting carcinoma. Blood pressure and antihypertensive requirement as well asserum potassium, aldosterone and direct renin (DRC)concentrations were evaluated before and after 1, 3, 5, 7, 15, 30, 60, 90, 120, 180, 270 and 360 days of adrenalectomy. Aldosterone and DRC postoperative recovery was arbitrary defined as ≥ 5 ng/dl and ≥ 5 mU/l, respectively.

Results: Hypertension was diagnosed at the mean age of 32 years (range 17–52). PA diagnosis was performed with a delay of sixteen years (25–64). The majority of patients had hypokalemia (83%). Post-operatively, median systolic and diastolic blood pressure decreased from 149 to 129 mmHg (P = 0.01) and from 91.6 to 81.6 mmHg (P = 0.04), respectively. Anti-hypertensive daily requirement was decreased and 16% of patients were normotensive with no medications. Median potassium levels increased from 2.8 to 4.7 mmol/l (P < 0.0001). The median aldosterone and DRC at diagnosis and at last follow up after surgery were 41 vs 5.5 ng/dl and 2 vs 9.1 mU/l (P < 0.0001).

Renin recovery was observed at median of 15 days (range 3-720) and aldosterone recovery at median of 120 days (5–720). The median difference between renin to aldosterone recovery was 52 days (2–263). In 77% of the patients the renin recovered earlier than aldosterone while in 23% they recoveredsimultaneously. No association was observed between these hormones recovery and age at diagnosis, time of disease, or potassium serum. However, patients with higher aldosterone levels at diagnosis (> 41 ng/dl) presented later renin (>15 days; P = 0.03) and aldosterone (>120 days; P = 0.008) recovery.

Conclusion: This is the first report, using a prospective protocol, comparing simultaneouslythe short and long-term time-course of aldosterone and renin levels recovery in APA after adrenalectomy. In spite of early renin recovery in most patients, the hypoaldosteronism remained elongated indicating that renin deficiency is not the main cause of postoperative hypoaldosteronism in patients with APA.