Diagnostic procedures for primary aldosteronism

Primary aldosteronism (PA) affects 5% to 10% of all patients with arterial hypertension and is mainly caused by either aldosterone producing adenoma or by idiopathic hyperaldosteronism due to bilateral adrenal hyperplasia. Patients with PA demonstrate a significantly increased risk of cardiovascular and renal disease when compared to patients with essential hypertension. However, PA can effectively be treated underlining the importance of screening for and diagnosing of PA. Measurement of the aldosterone to renin ratio (ARR) should be performed as a screening test. Patients with an elevated ARR should undergo confirmatory testing for PA, which generally aims to evaluate whether elevated aldosterone levels are suppressible by salt and volume loading or ACE inhibitor therapy. In patients with PA, subtype classification is important to identify patients who are eligible for surgical adrenalectomy (unilateral disease) and to differentiate them from patients with bilateral disease who should be treated with mineralocorticoid receptor antagonists. Adrenal imaging using computed tomography is the first step in subtype classification. Adrenal venous sampling is the preferred method to differentiate between unilateral and bilateral disease, but the posture test can also be useful in selected patients. The present review provides a brief overview of the diagnostic procedures for PA. Nevertheless, we acknowledge that the diagnostic accuracy of screening and confirmation tests for PA is at present insufficiently validated and further studies are required.