Are catecholamine-derived indexes in adrenal venous sampling useful for judging selectivity and laterality in patients with primary aldosteronism?

Utility of Epinephrine Levels in Determining Adrenal Vein Cannulation During Adrenal Venous Sampling for Primary Aldosteronism

OBJECTIVE

In patients with primary aldosteronism, adrenal venous sampling (AVS) is performed to determine the presence of unilateral or bilateral adrenal disease. During AVS, verification of catheter positioning within the left adrenal vein (AV) and the right AV by comparison of AV and inferior vena cava (IVC) cortisol levels can be variable. The objective of this study was to determine the utility of AV epinephrine levels in assessing successful AV cannulation.

METHODS

This was a single institution, retrospective review of patients who underwent AVS with cosyntropin stimulation for primary aldosteronism between 2009 and 2018. Successful cannulation of the AV was defined by an AV/IVC cortisol ratio selectivity index (SI) ≥3:1. Epinephrine thresholds to predict catheter placement in the AV were determined using logistic regression. The calculated epinephrine thresholds were compared with previously published thresholds.

RESULTS

AVS was performed on 101 consecutive patients and, based on the SI, successful cannulation of the left AV and right AV occurred in 98 (97%) and 91(90%) patients, respectively. The calculated optimal epinephrine threshold to predict AV cannulation was 364 pg/mL (sensitivity, 92.1%; specificity, 94.6%) and the calculated optimal AV/IVC epinephrine ratio threshold was 27.4, (sensitivity, 92.1%; specificity, 91.3%). Among the 14 patients with failed AV cannulation, 3 patients would have been considered to have successful AVS using AV epinephrine levels >364 pg/mL and AV/IVC epinephrine ratio >27.4 thresholds.

CONCLUSION

Obtaining 2 right AV samples routinely as well as AV and IVC epinephrine levels during AVS could prevent unnecessary repeat AVS in patients with failed AV cannulation based on cortisol-based SI <3:1.

Does concomitant autonomous adrenal cortisol overproduction have the potential to confound the interpretation of adrenal venous sampling in primary aldosteronism?

OBJECTIVE

Demonstration of unilateral aldosterone production by adrenal venous sampling (AVS) is required to select appropriate candidates for adrenalectomy in patients with primary aldosteronism (PA). During AVS, aldosterone and cortisol levels are measured to assess successful cannulation and lateralization. In patients with aldosterone-producing adenoma (APA), concurrent autonomous cortisol secretion might confound AVS results.

DESIGN AND PATIENTS

We retrospectively examined results in eight patients with cortisol-producing adenoma (CPA), but without PA, who underwent AVS.

RESULTS

In all eight, cortisol was higher on the CPA side than contralateral (CL) (median 6·7-fold [range 2·4-27·2]; P = 0·012]). By cortisol criteria, CL catheter placement would have been labelled inadequate in six despite adrenal venous aldosterone levels markedly higher than peripheral (41·6-fold [7·2-510·5]; P < 0·001), suggesting successful cannulation. In all eight, adrenal venous aldosterone/cortisol (A/C) ratios on the CL side were indicative of increased aldosterone production (≥2 times peripheral), but in only three patients on the CPA side (difference CL side 44·5-fold [6·0-109·0] vs CPA side 1·65-fold [1·0-23·0]; P = 0·017). A/C ratios were higher on the CL vs the CPA side in seven (20·0-fold [4·7-76·0]).

CONCLUSION

These results in patients with CPA suggest that in patients with APA, concurrent autonomous unilateral cortisol hypersecretion could confound AVS accuracy by increasing cortisol levels (reducing A/C ratio) on the CPA side, while reducing levels (increasing A/C ratio and suggesting failed cannulation) on the CL side. Misclassification of PA subtype or repeat AVS could result, underscoring the importance of adequately assessing cortisol production prior to AVS and the need to consider alternatives.

Primary aldosteronism: challenges in diagnosis and management

Primary aldosteronism (PA) is the main cause of endocrine hypertension, present in approximately 10% of hypertensive patients; about one-third is secondary to aldosterone-producing adenomas. Cardiovascular and renal morbidity are out of proportion to the degree of hypertension. Physicians have compelling rationale to correctly identify and treat PA. Physicians are challenged with patient selection for screening with the aldosterone/renin ratio (ARR), interpretation of ARR, and selecting a confirmatory test. Adrenal vein sampling is performed for subtype differentiation. The treatment depends on the disease subtype and results in control of hypertension and reversal of associated excess morbidity.

Hyperaldosteronism: diagnosis, lateralization, and treatment

Primary hyperaldosteronism is an important and commonly unrecognized secondary cause of hypertension. This article provides an overview of the current literature with respect to screening, diagnosis, and lateralization. Selection and outcomes of medical and surgical treatment are discussed.