Standardizing the Seated Saline Suppression Test for Primary Aldosteronism

BACKGROUND: Primary aldosteronism is the most common secondary endocrine form of hypertension. Specific treatment directly against aldosterone excess improves control of (and may cure) hypertension and reduces long-term cardiovascular and renal morbidity in patients with primary aldosteronism. Optimal treatment is guided by the results of adrenal venous sampling, with unilateral adrenalectomy being the preferred management for those with lateralizing forms and medical treatment with a mineralocorticoid antagonist for those with bilateral forms. Seated saline suppression testing, being highly specific for primary aldosteronism, provides a means of confirming the diagnosis and, being highly sensitive for lateralizing primary aldosteronism, allows selection of patients most likely to benefit from adrenal venous sampling and spares those with a negative seated saline suppression testing from having to undergo this invasive and expensive procedure. Recent studies, however, have reported poor performance of the seated saline suppression testing, probably in part due to deviation from published procedural methodology, including inappropriate patient selection, failure to render patients' potassium replete by the time of the test, or failure to commence the saline infusion on time. METHODS, RESULTS, AND CONCLUSIONS: This has prompted the development of a clear and comprehensive standard operating protocol for seated saline suppression testing so that high-quality test results can be more readily attained and usefully applied both for interpreting research studies and for clinical decision-making.