Utility of Repeat Sampling in Bilateral Aldosterone Suppression During Adrenal Vein Sampling for Primary Aldosteronism

Primary aldosteronism (PA) is the most common form of secondary hypertension. Accurate subtyping of PA is essential to identify unilateral disease, as adrenalectomy improves outcomes. Subtyping PA requires adrenal vein sampling (AVS), which is technically challenging and results from AVS may not always be conclusive. We present a case of a 37-year-old man with PA whose AVS studies were inconclusive due to apparent bilateral aldosterone suppression (ABAS). As a result, our patient was misdiagnosed as having bilateral PA and medically managed until a repeat AVS showed lateralization to the right adrenal gland. ABAS is an underrecognized phenomenon that may confound the subtyping of PA. We recommend repeating AVS in such cases and discuss strategies to minimize ABAS.

Duplicated adrenal veins in primary aldosteronism misdiagnosed with ectopic aldosteronoma due to apparent bilateral aldosterone suppression

BACKGROUND

Primary aldosteronism (PA) is considered the number one aetiology for secondary hypertension. Apart from confirmatory tests and localisation of PA determined by computed tomography (CT), adrenal venous sampling (AVS) is used to define whether aldosterone hypersecretion occurs inside one or both adrenal glands. However, even correctly-performed AVS may lead to undiagnostic results such as apparent bilateral adrenal suppression (apparent bilateral aldosterone suppression), in which the adrenal aldosterone-to-cortisol ratios (AC ratios) are decreased bilaterally compared to the peripheral blood sample, with several causes contributing to it.

CASE DESCRIPTION

Here, we describe the case of a 48-year-old man who was referred to our department for further investigation with a history of refractory hypertension, hypokalaemia, and aortic dissection. His hypertension and hypokalaemia were initially attributed to ectopic aldosteronoma due to his adrenal CT scan and AVS results. However, the correct diagnosis of an adenoma with duplicated right adrenal veins (duplicated adrenal veins) due to apparent bilateral aldosterone suppression was confirmed during surgery.

CONCLUSION

AVS is the gold standard accepted for PA subtyping, but sometimes when apparent bilateral aldosterone suppression is present, it can give ambiguous results. Duplicated right adrenal veins, may impact results, thus, AVS may not accurately provide evidence of unilateral hypersecretion for all PA patients. Repeat AVS or adrenal surgery can provide worthwhile diagnostic conclusions.