Primary aldosteronism: Diagnosis and therapy

Abstract

Primary aldosteronism (PA) is the most common cause of endocrine hypertension with an estimated prevalence of 5% among patients with arterial hypertension. PA is characterized by inadequately high aldosterone secretion from one or both adrenal glands. Diagnosis and therapy of PA is indicated because patients with PA have, compared to patients with essential arterial hypertension, even at the same blood pressure, a significantly higher cardiovascular risk, that can be effectively treated by specific therapy. Therefore, the Endocrine Society guidelines recommend broad screening for PA among hypertensive patients. The determination of the aldosterone-to-renin ratio (ARR) is the recommended screening test for PA. In the case of an elevated ARR, a confirmatory test (e. g. i. v. saline infusion test), should be performed. If PA is biochemically confirmed, subtype classification, i. e. differentiation between unilateral (aldosterone producing adenoma) and bilateral aldosterone hypersecretion (bilateral adrenal hyperplasia), is important because unilateral diseases can be treated by adrenal surgery whereas bilateral diseases are treated by drugs, e. g. mineralocorticoid receptor blockers. In addition to an adrenal computed tomography (CT), guidelines recommend adrenal venous sampling (i. e. blood collection for hormone measurement from the right and left adrenal vein) for subtype determination. Recent study results, however, suggest that CT based subtype classification and therapy of PA results in similar outcome when compared to adrenal venous sampling-based procedures. It is of concern that the recommendations of the guidelines for a wide PA screening in approximately every second patient with arterial hypertension is not implemented in routine clinical practice. Therefore, currently the vast majority of patients suffering from PA remains undiagnosed and untreated.