Appropriate timing for a biochemical evaluation after adrenalectomy for unilateral aldosterone-producing adenoma

Context: The oversecretion of plasma aldosterone by unilateral aldosterone-producing adenoma (APA) can be cured by adrenalectomy. However, the time needed for the endocrine environment to normalize remains unclear. Objective: To clarify adequate timing for a biochemical evaluation in unilateral APA patients after adrenalectomy. Design and patients: A total of 166 unilateral APA patients were retrospectively reviewed. We evaluated the plasma aldosterone concentration (PAC) (pg/mL), active renin concentration (ARC) (pg/mL), aldosterone-renin ratio (ARR; PAC/ARC), serum potassium concentration and estimated glomerular filtration rate (eGFR) at 1, 3 and 6 postoperation months (POM). Results: PAC was significantly lower at 1POM than at presurgery (presurgery; 407.2, 1 POM; 90.0 pg/mL, P <.001). ARC did not increase from baseline at 1POM, but significantly increased at 3POM (presurgery; 4.43, 1POM; 4.87, 3POM; 11.3 pg/mL, P <.001). ARR significantly decreased at 1POM (presurgery; 146.9, 1 POM; 26.3, P <.001) although ARC did not increase at 1POM. Among the 34 patients who had hypokalaemia presurgery, it was resolved in 28 (82%) at 1POM and in all (100%) at 3POM. The biochemical outcomes at 1POM were 131 (79%) complete, 20 (12%) partial and 15 (9%) absent successes, while at 3POM, 147 (89%) were complete, 9 (5%) partial and 10 (6%) absent. Twenty-three (14%) patients were reclassified into different biochemical outcomes between 1 and 3POM, whereas only 5 (3%) changed between 3 and 6POM. Conclusion: The appropriate timing for a biochemical evaluation of unilateral APA patients treated with laparoscopic adrenalectomy appears to be 3 months or more after surgery.