BACKGROUND The pre-operative use of mineralocorticoid receptor antagonists (MRA) in patients with unilateral forms of primary aldosteronism (PA) is not consistent. Postoperative hyperkalaemia after adrenalectomy for PA management has been reported in up to 16% of patients (1,2). It is unclear whether pre-operative MRA can optimise peri-operative blood pressure and potassium control, and reduce the incidence of postoperative hyperkalaemia.
OBJECTIVE This study aimed to investigate the effect of pre-operative MRA on peri-operative blood pressure and potassium concentration, and the incidence of postoperative hyperkalaemia in patients undergoing unilateral adrenalectomy for the treatment of PA.
METHODS In this retrospective cohort study, a total of 96 patients with unilateral PA from a tertiary endocrine surgery database were included for analysis. Seventy-three patients (‘MRA’ group) received pre-operative MRA while 23 patients (‘No-MRA’ group) did not. The main outcome measures included the incidence of postoperative hyperkalaemia within 2 years after adrenalectomy, in addition to blood pressure and serum potassium concentration just prior to surgery.
RESULTS Spironolactone, an MRA, was administered at a median dose of 75mg for four months pre-operatively. The prevalence of postoperative hyperkalaemia was significantly higher in the ‘No-MRA’ group at 2-4 weeks after surgery, compared to the ‘MRA’ group (35% vs 11%, p=0.014, Figure 1). Logistic regression found the use of MRA to significantly predict a lower incidence of postoperative hyperkalaemia after adjusting for age, sex, baseline aldosterone-to-renin ratio and potassium concentration (b=-2.029, p=0.012). Prior to surgery, patients in the ‘MRA’ group had normalised blood pressure and potassium concentration with fewer antihypertensive medications and no potassium supplements.
CONCLUSION Pre-operative MRA use was associated with optimal perioperative blood pressure and normalised serum potassium in addition to a lower incidence of postoperative hyperkalaemia. MRA should be considered standard treatment for patients awaiting surgery for PA.