Intraprocedural Cortisol Testing During Adrenal Vein Sampling for Primary Aldosteronism: Weighing the Benefits and Limitations

Primary aldosteronism (PA) is characterized by renin-independent aldosterone secretion from one or both adrenal glands leading to inappropriate mineralocorticoid receptor (MR) activation and blood pressure elevation. While still woefully underdiagnosed PA is increasingly recognized as the most common yet modifiable form of secondary hypertension. Modern-day prevalence studies demonstrate that 10%–20% of all cases of hypertension are attributable to PA, including a direct association between hypertension severity and PA prevalence. Notably, PA leads to a disproportionately higher risk for cardiovascular, metabolic, and kidney disease compared with essential hypertension, even independent of blood pressure. In the process of evaluating a patient with PA, a key determination to make is whether the source of aldosterone excess lateralizes to one adrenal gland or not. This distinction will guide whether the recommended treatment will involve surgical adrenalectomy (lateralizing PA) or lifelong MR antagonist therapy (nonlateralizing PA). Importantly, a number of observational studies have demonstrated substantially improved long-term health outcomes with adrenalectomy compared with MR antagonist therapy in lateralizing PA. Determination of disease lateralization, and thereby candidacy for adrenalectomy, is a 2-step process including adrenal protocol CT or MRI along with adrenal vein sampling (AVS). CT/MRI alone is generally insufficient to determine disease lateralization as it may produce misleading results,11 and AVS (considered the current “gold standard” for PA lateralization) is typically required prior to proceeding with adrenalectomy.