Adrenal venous sampling in primary hyperaldosteronism: correlation of hormone indices and collimated C-arm CT findings

Strategies for subtyping primary aldosteronism

Adrenal venous sampling (AVS) is a crucial method for the lateralization of primary aldosteronism (PA). It is advised to halt the use of the patient's antihypertensive medications and correct hypokalemia prior to undergoing AVS. Hospitals equipped to conduct AVS should establish their own diagnostic criteria based on current guidelines. If the patient's antihypertensive medications cannot be discontinued, AVS can be performed as long as the serum renin level is suppressed. The Task Force of Taiwan PA recommends using a combination of adrenocorticotropic hormone stimulation, quick cortisol assay, and C-arm cone-beam computed tomography to maximize the success of AVS and minimize errors by using the simultaneous sampling technique. If AVS is not successful, an NP-59 (131 I-6-β-iodomethyl-19-norcholesterol) scan can be used as an alternative method to lateralize PA. We depicted the details of the lateralization procedures (mainly AVS, and alternatively NP-59) and their tips and tricks for confirmed PA patients who would consider to undergo surgical treatment (unilateral adrenalectomy) if the subtyping shows unilateral disease.

Adrenal Vein Sampling: Does the Location of the Non-adrenal Venous Sample Matter?

PURPOSE

Adrenal vein sampling (AVS) is used to lateralise and differentiate unilateral from bilateral aldosterone production in primary aldosteronism. The adrenal venous samples are standardised to a peripheral or low inferior vena cava (IVC) sample and compared. It is unknown whether the location of the non-adrenal sample affects the results. This study compares AVS results standardised to the low IVC and right external iliac vein (REIV).

METHODS

Patients who underwent AVS between March 2021 and May 2023 were included. All procedures were undertaken by a single operator (AA). Demographic data and AVS results were collected from patients' electronic records. Catheterisation success and lateralisation were assessed using both low IVC and REIV samples. Equivalence test was used to compare the cortisol and aldosterone levels.

RESULTS

Eighty-one patients, (M: F = 38:43), aged between 29 and 74 were included. Bilateral successful adrenal vein cannulation was achieved in 79/81 (97.5%) cases. The mean cortisol levels from the REIV were statistically equivalent although there was a small and not biologically significant difference from the low IVC (respective geometric means 183 nmol/l vs. 185 nmol/l, p = 0.015). This small difference in cortisol may be due to accessory adrenal venous drainage into the IVC. The aldosterone and aldosterone/cortisol ratios were statistically equivalent. There was no discordance in selectivity or lateralisation when the IVC or REIV measurements were used.

CONCLUSION

The IVC and REIV samples may be used interchangeably during AVS.

RAS-challenge as a first-look test for detection of primary aldosteronism in patients with treatment-resistant hypertension

PURPOSE

Primary aldosteronism (PA), characterised by low-renin hypertension, confers a high cardiovascular risk and is the most common cause of secondary hypertension, with an increased prevalence in patients with treatment-resistant hypertension. However, it is estimated that only a small percentage of affected patients are identified in routine clinical practice. Inhibitors of the renin-angiotensin system cause an increase in renin levels in patients with intact aldosterone regulation, and inadequate low renin with concurrent RAS inhibition (RASi) may therefore indicate PA, which could serve as a first look screening test for selection for formal work-up.

METHODS

We analysed patients between 2016-2018 with treatment-resistant hypertension who had inadequate low renin in the presence of RASi (i. e. at risk for PA) and who were offered systematic work-up with adrenal vein sampling (AVS).

RESULTS

A total of 26 pts were included in the study (age 54.8 ± 11, male 65%). Mean office blood pressure (BP) was 154/95 mmHg on 4.5 antihypertensive drug classes. AVS had a high technical success rate (96%) and demonstrated unilateral disease in the majority of patients (57%), most of which (77%) were undetected by cross-sectional imaging.

CONCLUSION

In patients with resistant hypertension, low renin in the presence of RASi is a strong indicator for autonomous aldosterone secretion. It may serve as an on-medication screening test for PA to select for formal PA work up.

Cone-beam computed tomography is not a mandatory procedure in adrenal venous sampling for primary hyperaldosteronism

Objectives

To investigate the necessity of cone-beam computed tomography (CBCT) in adrenal venous sampling (AVS).

Methods

This retrospective study included 120 consecutive patients with primary hyperaldosteronism who underwent AVS. Based on the learning curve of the interventional radiologists, the patients were divided into the learning (n = 36) and proficiency (n = 84) groups chronologically. Based on the imaging pattern of the right adrenal vein (RAV), the patients were divided into the typical (n = 36) and atypical (n = 84) groups. The success rate, radiation dose, and sampling time were compared among the entire study population and each subgroup.

Results

A total of 69 patients underwent CBCT, whereas 51 patients did not. The overall success rate was 85.8%, and no difference was noted between patients with and without CBCT (P = 0.347). However, radiation dose (P = 0.018) and sampling time (P = 0.001) were significantly higher in patients who underwent CBCT than in patients who did not. In learning group, CBCT improved success rate from 62.5 to 96.4% (P = 0.028), whereas it was not found in the proficiency group (P = 0.693). Additionally, success rate in patients with an atypical RAV imaging pattern was significantly higher when CBCT was used than when it was not used (P = 0.041), whereas no difference was noted in patients with typical RAV imaging pattern (P = 0.511).

Conclusion

For physicians not very experienced doing AVS, there is a clear significant improvement in success rate when CBCT is used. However, CBCT only has minimal benefit for experienced operators, meanwhile CBCT may take an extra time and increase the radiation dose during AVS.

Adrenal venous sampling in the diagnostic workup of primary aldosteronism

Primary aldosteronism (PA) is the primary cause of secondary hypertension. The prevalence of PA has probably been underestimated in the past and recent studies suggest that PA could be present in up to 10% of patients suffering from hypertension. Aldosterone excess in PA can be caused by unilateral adrenal disease, usually adrenal adenoma, or bilateral adrenal hyperplasia. Differentiation between unilateral and bilateral disease is clinically important as the former can effectively be treated by removal of the affected adrenal. CT or MRI cannot reliably distinguish unilateral from bilateral disease. Therefore, adrenal vein sampling (AVS) is an important step of the diagnostic work-up in patients with PA. Current guidelines recommend PA in virtually all patients with biochemically diagnosed PA who would undergo adrenal surgery if unilateral PA was diagnosed. In this narrative review, we give an overview of the current technique used for AVS with a focus on the experience with this technique at the University Hospital Basel, Switzerland.