Effects of mineralocorticoid and AT1 receptor antagonism on the aldosterone-renin ratio in primary aldosteronism-the EMIRA study

Abstract

Context: While current guidelines recommend the withdrawal of mineralocorticoid receptorantagonist (MRA) and renin-angiotensin system blockers for the screening and detection of primaryaldosteronism (PA), this can worsen hypokalemia and control of high blood pressure (BP) values.Objective: To investigate whether aldosterone/renin ratio (ARR) values were affected by theMRA canrenone and/or by canrenone plus olmesartan treatment in patients with PA.Design: Within-patient study.Setting: The European Society of Hypertension center of excellence at the University of Padua.Patients: Consecutive patients with an unambiguous diagnosis of PA subtyped by adrenal veinsampling.Interventions: Patients were treated for 1 month with canrenone (50-100 mg orally), andfor an additional month with canrenone plus olmesartan (10-20 mg orally). Canrenone andolmesartan were up-titrated over the first 2 weeks until BP values and hypokalemia werecontrolled. Patients with unilateral PA were adrenalectomized; those with bilateral PA weretreated medically.Main Outcome Measures: BP, plasma levels of sodium and potassium, renin and aldosterone.Results: Canrenone neither lowered plasma aldosterone nor increased renin; thus, the high ARRand true positive rate remained unaffected. Addition of the angiotensin type 1 receptor blockerraised renin and slightly lowered aldosterone, which reduced the ARR and increased the falsenegative rate.Conclusions: At doses that effectively controlled serum potassium and BP values, canrenonedid not preclude an accurate diagnosis in patients with PA. Addition of the angiotensin type 1receptor blocker olmesartan slightly raised the false negative rate. Hence, MRA did not seem toendanger the accuracy of the diagnosis of PA.