Diagnostic Approach for Primary Aldosteronism in Resistant Hypertension

Understanding the Current Clinical Picture

The European Society of Cardiology suggests that patients with resistant hypertension (uncontrolled despite multiple medications including ARB, calcium channel blocker, diuretics, beta blockers, and eplerenone) should undergo confirmatory testing for primary aldosteronism if the aldosterone-to-renin ratio (ARR) is elevated >111 1, 3
The elevated ARR >111 strongly suggests primary aldosteronism, which is present in up to 20% of patients with resistant hypertension, according to the European Heart Journal 4

The European Society of Cardiology recommends that mineralocorticoid receptor antagonists (eplerenone) should be withdrawn at least 4 weeks before confirmatory testing, if possible 2
Other interfering medications that should be discontinued when feasible include beta-blockers, ARBs, and diuretics, as they can cause false positives or negatives in confirmatory tests 1, 5
If medications cannot be safely discontinued, the European Society of Cardiology suggests that testing can still proceed with careful interpretation of results in the context of current medications 5, 3

The European Heart Journal recommends an intravenous saline suppression test or oral salt-loading test as confirmatory tests for primary aldosteronism 1, 2
The intravenous saline suppression test involves administration of 2L of 0.9% saline over 4 hours with measurement of aldosterone before and after, while the oral salt loading test involves a high sodium diet with 24-hour urine collection for aldosterone 2

Adrenal imaging with high-resolution CT or MRI can identify potential adenomas, and adrenal venous sampling (AVS) can distinguish between unilateral and bilateral disease, especially in patients >40 years old 4, 2

The European Society of Cardiology emphasizes the importance of ensuring normal serum potassium before testing, as hypokalemia can suppress aldosterone production and lead to false-negative results 2
The European Heart Journal recommends assessing sodium intake before testing, as it affects the ARR interpretation 1, 2
False positives can occur in low-renin states even without truly elevated aldosterone levels, highlighting the need for confirmatory testing 2, 4

If primary aldosteronism is confirmed and subtyped, the European Society of Cardiology recommends considering laparoscopic adrenalectomy for unilateral aldosterone-producing adenoma, and optimizing medical therapy with mineralocorticoid receptor antagonists for bilateral adrenal hyperplasia 2