Effects of Mineralocorticoid and AT1 Receptor Antagonism on The Aldosterone-Renin Ratio In Primary Aldosteronism—the EMIRA Study

Abstract

Context The withdrawal of mineralocorticoid-receptor antagonist (MRA) and renin-angiotensin system blockers recommended in current guidelines for case detection of primary aldosteronism (PA) can worsen hypokalemia and control of high blood pressure (BP) values. Objective To investigate if aldosterone/renin ratio (ARR) values were affected by the MRA 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 vein sampling (AVS). Interventions Patients were treated for one-month treatment with canrenone (50-100 mg orally), and a further month with canrenone plus olmesartan (10-20 mg orally). Canrenone and olmesartan were up-titrated over the first two weeks until BP values and hypokalemia were controlled. Patients with unilateral PA were adrenalectomized; those with bilateral PA were treated medically. Main Outcome Measures BP, plasma levels of sodium and potassium, renin, and aldosterone. Results Canrenone neither lowered plasma aldosterone nor did raise renin, thus leaving the high ARR and true positive rate unaffected. Addition of the angiotensin type 1 receptor blocker raised renin and slightly lowered aldosterone, thus reducing the ARR and increasing the false negative rate. Conclusions At doses that effectively controlled serum potassium and BP values, canrenone did not preclude an accurate diagnosis in patients with PA. Addition of the angiotensin type 1 receptor blocker olmesartan slightly raised the false negative rate. Hence, MRA did not seem to endanger the accuracy of the diagnosis of PA.