Adrenal venous sampling should be performed before adrenalectomy in primary aldosteronism?
Primary aldosteronism (PA) is the most frequent form of endocrine hypertension. The identification of the subtype of PA is fundamental to distinguish between subtypes that benefit from surgery and subtypes that should be treated pharmacologically with mineralocorticoid receptor antagonists. CT scanning is the most sensitive imaging technique for the identification of adrenal nodules but lacks sensitivity and specificity. Also posture test and other clinical criteria of high probability of APA have shown to be unreliable in distinguishing between PA subtypes. Adrenal vein sampling (AVS) is considered the only reliable technique that allows the clinician to define the patients that should undergo unilateral adrenalectomy. During AVS, blood is collected from the inferior vena cava, from a peripheral vein and from both adrenal veins and aldosterone and cortisol are measured in each sample. The cortisol concentration in the samples are a measure of the adequacy of the adrenal vein cannulation. There is no agreement on which criteria should be used for considering a successful cannulation of the adrenal veins and for considering the aldosterone secretion lateralized and therefore, to suggest adrenalectomy. We suggest to use restrictive criteria, especially for demonstrating the correct cannulation of the adrenal veins. Monitoring of cortisol during the catheterization procedure allows any improperly collected adrenal samples to be immediately re-collected. We recently reported a quick and reliable cortisol assay performed in the operating room during the AVS, allowing the radiologist further attempts at cannulation until cortisol measurements demonstrate the success of the sampling. The recently published Guidelines of the Endocrine Society suggest that AVS should be performed in all patients in whom the adrenalectomy is considered. In fact adrenal vein sampling is the only reliable technique that allows the differentiation between PA subtypes and therefore, it should always be performed in patients who are potential candidates for surgery.