Diagnosis of Surgically-Treatable Forms of Primary Aldosteronism

Primary aldosteronism (PA) is a common form of endocrine hypertension in which aldosterone production is inappropriate and at least partially autonomous of the renin-angiotensin system. Recent studies using the plasma aldosterone/plasma renin activity (PRA) ratio (ARR) as a screening test for both hypokalaemic and normokalaemic hypertensives have reported a high prevalence of this disease, with PA accounting for up to 12% of hypertensive patients. Therefore, PA is considered the most common identifiable, specifically treatable and potentially curable form of hypertension. Of particular interest is the identification of the different subtypes of PA, since some of them benefit from surgical treatment, whereas others require medical treatment with mineralocorticoid receptor antagonists. Herein, we review the diagnostic strategies used to identify surgically-treatable forms of PA, i.e. those forms that display unilateral secretion of aldosterone and benefit from unilateral adrenalectomy. In particular, we compare the different imaging strategies, the role of hormonal tests and the indication and interpretation of adrenal venous sampling.