Clinical risk factors of postoperative hyperkalemia after adrenalectomy in patients with aldosterone-producing adenoma.

OBJECTIVE Unilateral adrenalectomy is the first-line treatment for aldosterone-producing adenomas (APA). Hyperkalemia after adrenalectomy because of contralateral zona glomerulosa insufficiency has been reported. We investigated clinical risk factors to predict postoperative hyperkalemia in patients with APA undergoing adrenalectomy. DESIGN AND METHODS This study was conducted by retrospectively reviewing medical records from 2000 to 2012 at Seoul National University Hospital and two other tertiary centers. Data from 124 patients who underwent adrenalectomy were included. Hyperkalemia was defined as serum potassium >5.5 mmol/l. Clinical preoperative risk factors included age, blood pressure, plasma renin activity (PRA), plasma aldosterone concentration (PAC), serum potassium, serum creatinine, glomerular filtration rate (GFR), the mass size on pathology, and mineralocorticoid receptor (MR) antagonist use. RESULTS Out of 124 patients, 13 (10.5%) developed postoperative hyperkalemia. The incidences of transient and persistent hyperkalemia were 3.2 and 7.3% respectively. Preoperative PRA and PAC were not significantly different in postoperative hyperkalemic patients compared with normokalemic patients. Patients with persistent hyperkalemia were older, had a longer duration of hypertension, larger mass size on pathology, and lower GFR (all P<0.05). The incidence of postoperative hyperkalemia was not different between MR antagonist users and non-users. CONCLUSION Older age (≥53 years), longer duration of hypertension (≥9.5 years), larger mass size on pathology (≥1.95 cm), and impaired preoperative renal function (GFR <58.2 ml/min) were associated with prolonged postoperative hyperkalemia in patients with APA. MR antagonist use did not prevent postoperative hyperkalemia.