Clinical outcomes of primary aldosteronism based on lateralization index and contralateral suppression index after adrenal venous sampling in real-world practice: a retrospective cohort study

Adrenal Vein Sampling for Primary Aldosteronism: Recommendations From the Australian and New Zealand Working Group

Adrenal vein sampling (AVS) is the current recommended procedure for identifying unilateral subtypes of primary aldosteronism (PA), which are amenable to surgery with the potential for cure. AVS is a technically challenging procedure usually undertaken by interventional radiologists at tertiary centres. However, there are numerous variations in AVS protocols relating to patient preparation, sampling techniques and interpretation which may impact the success of AVS and patient care. To reduce practice variations, improve the success rates of AVS and optimise patient outcomes, we established an Australian and New Zealand AVS Working Group and developed evidence-based expert consensus recommendations for the preparation, performance and interpretation of AVS. These recommendations can be used by all healthcare professionals in a multidisciplinary team who look after the diagnosis and management of PA.

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.

Unilaterally Selective Adrenal Vein Sampling for Identification of Surgically Curable Primary Aldosteronism

BACKGROUND

Adrenal venous sampling is recommended for the identification of unilateral surgically curable primary aldosteronism but is often clinically useless, owing to failed bilateral adrenal vein cannulation.

OBJECTIVES

To investigate if only unilaterally selective adrenal vein sampling studies can allow the identification of the responsible adrenal.

METHODS

Among 1625 patients consecutively submitted to adrenal vein sampling in tertiary referral centers, we selected those with selective adrenal vein sampling results in at least one side; we used surgically cured unilateral primary aldosteronism as gold reference. The accuracy of different values of the relative aldosterone secretion index (RASI), which estimates the amount of aldosterone produced in each adrenal gland corrected for catheterization selectivity, was examined.

RESULTS

We found prominent differences in RASI values distribution between patients with and without unilateral primary aldosteronism. The diagnostic accuracy of RASI values estimated by the area under receiver operating characteristic curves was 0.714 and 0.855, respectively, in the responsible and the contralateral side; RASI values >2.55 and ≤0.96 on the former and the latter side furnished the highest accuracy for detection of surgically cured unilateral primary aldosteronism. Moreover, in the patients without unilateral primary aldosteronism, only 20% and 16% had RASI values ≤0.96 and >2.55.

CONCLUSIONS

With the strength of a large real-life data set and use of the gold reference entailing an unambiguous diagnosis of unilateral primary aldosteronism, these results indicate the feasibility of identifying unilateral primary aldosteronism using unilaterally selective adrenal vein sampling results.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01234220.

Intraprocedural cortisol testing improves adrenal vein cannulation success and diagnostic accuracy in assessment of primary aldosteronism, in a medium throughput centre

Primary aldosteronism is the most common cause of secondary hypertension. Identifying individuals who have unilateral secretion from aldosterone secreting adenomas allows adrenalectomy. Surgical treatment when feasible may be superior to medical management with improved cardiovascular outcomes and reduced medication dependence. Adrenal vein sampling (AVS) is required to biochemically lateralise aldosterone secretion prior to adrenalectomy. However, diagnostic success of AVS is variable and can be poor even at tertiary centres; failure is largely due to unsuccessful adrenal vein cannulation. Intra-procedural rapid semiquantitative cortisol testing (RCT) identifies correct catheter placement in real time. We compared diagnostic success rates of AVS before and after the introduction of intraprocedural cortisol testing at the Royal Adelaide Hospital-a medium throughput tertiary centre (average 6.2 procedures a year over the last 8 years). We observed an increase in success rate from 63% to 94%. Intraprocedural cortisol testing also led to a net financial saving of ~$100 AUD per procedure. RCT is likely to be cost effective if pre-RCT success rate is less than 78%. Procedure time and number of samples collected, however, were increased with RCT. This suggests that intraprocedural cortisol testing will improve success in low to medium throughput centres and may make AVS feasible in less specialised centres.

Integration of clinical parameters and CT-based radiomics improves machine learning assisted subtyping of primary hyperaldosteronism

Objectives

The aim of this study was to investigate an integrated diagnostics approach for prediction of the source of aldosterone overproduction in primary hyperaldosteronism (PA).

Methods

269 patients from the prospective German Conn Registry with PA were included in this study. After segmentation of adrenal glands in native CT images, radiomic features were calculated. The study population consisted of a training (n = 215) and a validation (n = 54) cohort. The k = 25 best radiomic features, selected using maximum-relevance minimum-redundancy (MRMR) feature selection, were used to train a baseline random forest model to predict the result of AVS from imaging alone. In a second step, clinical parameters were integrated. Model performance was assessed via area under the receiver operating characteristic curve (ROC AUC). Permutation feature importance was used to assess the predictive value of selected features.

Results

Radiomics features alone allowed only for moderate discrimination of the location of aldosterone overproduction with a ROC AUC of 0.57 for unilateral left (UL), 0.61 for unilateral right (UR), and 0.50 for bilateral (BI) aldosterone overproduction (total 0.56, 95% CI: 0.45-0.65). Integration of clinical parameters into the model substantially improved ROC AUC values (0.61 UL, 0.68 UR, and 0.73 for BI, total 0.67, 95% CI: 0.57-0.77). According to permutation feature importance, lowest potassium value at baseline and saline infusion test (SIT) were the two most important features.

Conclusion

Integration of clinical parameters into a radiomics machine learning model improves prediction of the source of aldosterone overproduction and subtyping in patients with PA.

Primary Aldosteronism and Drug Resistant Hypertension: A "Chicken-Egg" Story

Drug-resistant arterial hypertension (RH) is a major risk factor for cardiovascular disease, often due to overlooked underlying causes. Identification of such causes poses significant clinical challenges. In this setting, primary aldosteronism (PA) is a frequent cause of RH and its prevalence in RH patients is likely higher than 20%.The pathophysiological link between PA and the development and maintenance of RH involves target organ damage and the cellular and extracellular effects of aldosterone excess that promote pro-inflammatory and pro-fibrotic changes in the kidney and vasculature.The feasibility of adrenal vein sampling in PA patients with RH, and the clinical benefit achieved by adrenalectomy, further emphasize the need to implement systematic screening for this common form of secondary hypertension in the management of a high-risk population as RH patients.: We herein review the current knowledge of the factors that contribute to the RH phenotype with a focus on PA and discuss the issues regarding the screening for PA in this setting and the therapeutic approaches (surgical and medical) aimed at resolving RH caused by PA.

Prognostic value of contralateral suppression on kidney function after surgery in patients with primary aldosteronism

BACKGROUND AND OBJECTIVE

Adrenalectomy for primary aldosteronism (PA) has been associated with decreased kidney function after surgery. It has been proposed that elimination of excess aldosterone unmasks an underlying failure of the kidney function. Contralateral suppression (CLS) is considered a marker of aldosterone excess and disease severity, and the purpose of this study was to assess the hypothesis that CLS would predict change in kidney function after adrenalectomy in patients with PA.

DESIGN AND PATIENTS

Patients with PA referred for adrenal venous sampling (AVS) between May 2011 and August 2021 and who were subsequently offered surgical or medical treatment were eligible for the current study.

RESULTS

A total of 138 patients were included and after AVS 85/138 (61.6%) underwent adrenalectomy while 53/138 (38.4%) were treated with MR-antagonists. In surgically treated patients the estimated glomerular filtration rate (eGFR) was reduced by 11.5 (SD: 18.5) compared to a reduction of 5.9 (SD: 11.5) in medically treated patients (p = .04). Among surgically treated patients, 59/85 (69.4%) were classified as having CLS. After adrenalectomy, patients with CLS had a mean reduction in eGFR of 17.5 (SD: 17.6) compared to an increase of 1.8 (SD: 12.8) in patients without CLS (p < .001). The association between CLS and change in kidney function remained unchanged in multivariate analysis. Post-surgery, 16/59 (27.1%) patients with CLS developed hyperkalemia compared to 2/26 (7.7%) in patients without CLS (p = .04).

CONCLUSION

This retrospective study found that CLS was a strong and independent predictor of a marked reduction of eGFR and an increased risk of hyperkalemia after adrenalectomy in patients with PA.

Prognostic value of contralateral suppression for remission after surgery in patients with primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is the most common cause of endocrine hypertension and adrenalectomy is the firstline treatment for unilateral PA. Suppression of aldosterone secretion of the nondominant adrenal gland at adrenal venous sampling (AVS), that is, contralateral suppression (CLS) has been suggested as a marker of disease severity. However, whether factors such as CLS, age, gender or comorbidities are associated with remission after surgery is controversial. The objective of this study is to investigate the prognostic value of CLS, age, gender, aldosterone-to-renin ratio, antihypertensives and comorbidities for clinical and biochemical remission following unilateral adrenalectomy in patients with PA.

DESIGN AND PATIENTS

A retrospective study of patients with PA referred for AVS at Rigshospitalet from May 2011 to September 2020, who subsequently underwent adrenalectomy. Clinical remission was defined according to the PA surgical outcome criteria, whereas complete biochemical remission was defined as normalization of hypokalaemia without potassium substitution.

RESULTS

Eighty-four patients were available for analysis of primary outcome. Among patients with CLS, 28/58 (48.3%) obtained complete clinical remission after surgery compared with 10/26 (38.5%) without CLS (p = .40). Complete biochemical remission was obtained in 55/58 (94.8%) of patients with CLS compared with 25/28 (89.3%) without CLS (p = .44). Female gender and lower number of antihypertensives at baseline were associated with higher odds for complete clinical remission, whereas none of the investigated variables were associated with biochemical remission.

CONCLUSION

CLS was not significantly associated with complete clinical or biochemical remission in this cohort. Our results confirmed that female gender and lower number of antihypertensives were predictors of clinical remission.

Indices of ACTH-stimulated adrenal venous sampling as predictors of postsurgical outcomes in primary aldosteronism

OBJECTIVE

This study aimed to investigate the impact of indices of adrenal venous sampling (AVS) on postsurgical outcomes in patients with primary aldosteronism (PA).

DESIGN AND PATIENTS

This retrospective study determined biochemical and clinical outcomes based on ACTH-stimulated AVS parameters (lateralisation index [LI], contralateral ratio [CLR], and ipsilateral ratio [ILR]) in 251 patients with PA at 3 months after surgery.

RESULTS

Modified complete biochemical success was achieved in 8 of 12 (66.7%) patients with LI = 3-4, 39 of 47 (83.0%) with LI = 4-10, and 155 of 169 (91.7%) with LI ≥ 10 (p = .004 for trend). Modified complete biochemical success was achieved in 29 of 38 (76.3%) patients with CLR ≥ 1 and ILR ≤ 2, 73 of 86 (84.9%) with CLR = 0.25-1 and ILR > 2, and 100 of 104 (96.2%) with CLR < 0.25 and ILR > 2 (p = .001 for trend). After adjusting for confounders, modified complete biochemical success was associated with an LI ≥ 10 (odds ratio [OR] = 6.32; 95% confidence interval [CI] = 1.33-29.93) using LI = 3-4 as a reference and combined CLR < 0.25 and ILR > 2 (OR = 11.49; 95% confidence interval [CI] = 2.49-53.01) using combined CLR ≥ 1 and ILR ≤ 2 as a reference. Using combined CLR ≥ 1 and ILR ≤ 2 as a reference, complete clinical success was associated with combined CLR < 0.25 and ILR > 2 (OR = 3.10; 95% CI = 1.03-9.28) and combined CLR = 0.25-1 and ILR > 2 (OR = 4.92; 95% CI = 1.64-14.76).

CONCLUSION

LI ≥ 10 may be appropriate for achieving biochemical success. With ILR > 2, CLR < 0.25, and CLR < 1 may be appropriate for achieving biochemical and clinical success, respectively.

Primary Aldosteronism Presenting with Hypertension Five Days after Delivery: A Case Report and Literature Review

A 35-year-old Japanese woman with no history of hypertension developed hypertension 5 days after normal delivery. Endocrinological and radiological examinations indicated primary aldosteronism (PA) and a 1.4-cm left adrenal tumor. The patient underwent laparoscopic adrenalectomy, and a diagnosis of aldosterone-producing adenoma was confirmed immunohistochemically. Her plasma aldosterone concentration and blood pressure normalized. Cases of PA presenting with hypertension in the postpartum period have been reported. This case suggests that PA should be considered in women with postpartum hypertension, especially in those with blood pressure that suddenly increases shortly after delivery, even if they were normotensive before and throughout pregnancy.

Morphologically Normal-Appearing Adrenal Glands as a Prevalent Source of Aldosterone Production in Primary Aldosteronism

BACKGROUND

Normal-appearing adrenal glands on cross-sectional imaging may still be the source of aldosterone production in primary aldosteronism (PA).

METHODS

We evaluated the prevalence of aldosterone production among morphologically normal-appearing adrenal glands and the impact of this phenomenon on interpretations of localization studies and treatment decisions. We performed a retrospective cohort study of PA patients with at least 1 normal adrenal gland and reanalyzed contemporary studies to assess interpretations of imaging and adrenal venous sampling (AVS) at the individual patient and adrenal levels.

RESULTS

Among 243 patients, 43 (18%) had bilateral normal-appearing adrenals and 200 (82%) had a unilateral normal-appearing adrenal, for a total of 286 normal-appearing adrenal glands. 38% of these normal-appearing adrenal glands were a source of aldosteronism on AVS, resulting in discordance between imaging and AVS findings in 31% of patients. Most patients with lateralizing PA underwent curative unilateral treatment (80%); however, curative treatment was pursued in 92% of patients who had concordant imaging-AVS results but in only 38% who had discordant results (P < 0.05). In young patients, imaging-AVS discordance was detected in 32% of those under 45 years and 21% of those under 35 years. Among 20 contemporary studies (including 4,904 patients and 6,934 normal-appearing adrenal glands), up to 64% of normal-appearing adrenals were a source of aldosteronism resulting in 31% of patients having discordant results.

CONCLUSIONS

Morphologically normal-appearing adrenal glands are commonly the source of aldosterone production in PA, even among young patients. The lack of awareness of this issue may result in inappropriate treatment recommendations.

Adrenal Venous Sampling for Subtype Diagnosis of Primary Hyperaldosteronism

Adrenal venous sampling (AVS) is the key procedure for lateralization of primary hyperaldosteronism (PA) before surgery. Identification of the adrenal veins using computed tomography (CT) and intraoperative cortisol assay facilitates the success of catheterization. Although administration of adrenocorticotropic hormone (ACTH) has benefits such as improving the success rate, some unilateral cases could be falsely diagnosed as bilateral. Selectivity index of 5 with ACTH stimulation to assess the selectivity of catheterization and lateralization index (LI) >4 with ACTH stimulation for unilateral diagnosis is used in many centers. Co-secretion of cortisol from the tumor potentially affects the lateralization by the LI. Patients aged <35 years with hypokalemia, marked aldosterone excess, and unilateral adrenal nodule on CT have a higher probability of unilateral disease. Patients with normokalemia, mild aldosterone excess, and no adrenal tumor on CT have a higher probability of bilateral disease. Although no methods have 100% specificity for subtype diagnosis that would allow bypassing AVS, prediction of the subtype should be considered when recommending AVS to patients. Methodological standardization and strict indication improve diagnostic quality of AVS. Development of non-invasive imaging and biochemical markers will drive a paradigm shift in the clinical practice of PA.

Characteristics of a Novel ATP2B3 K416_F418delinsN Mutation in a Classical Aldosterone-Producing Adenoma

Simple Summary

The ATP2B3 channel mutation is a rare cause of primary aldosteronism (PA). ATP2B3 gene mutation leads to the dysfunction of calcium channel that pumps calcium ion out of the cell and accumulates intracellular calcium signal to stimulate aldosterone synthesis. In the present study, we found a novel somatic ATP2B3 K416_F418delinsN mutation in a PA patient, and proved its functionality by demonstrating aldosterone hyper-function in the mutant-transfected adrenal cell-line. The ATP2B3 K416_F418delinsN mutation resulted from the deletion from nucleotides 1248 to 1253. The translated amino acid sequence from 416 to 418 as lysine-phenylalanine-phenylalanine was deleted and an asparagine was inserted due to the merging of residual nucleotide sequences.

Abstract

In patients with primary aldosteronism (PA), the prevalence of ATP2B3 mutation is rare. The aim of this study is to report a novel ATP2B3 mutation in a PA patient. Based on our tissue bank of aldosterone-producing adenomas (APA), we identified a novel somatic ATP2B3 K416_F418delinsN mutation. The affected individual was a 53 year-old man with a 4 year history of hypertension. Computed tomography (CT) showed bilateral adrenal masses of 1.6 (left) and 0.5 cm (right) in size. An adrenal venous sampling (AVS) showed a lateralization index (LI) of 2.2 and a contralateral suppression index (CLS) of 0.12; indicating left functional predominance. After a left unilateral adrenalectomy, he achieved partial biochemical and hypertension–remission. This classical adenoma harbored a novel ATP2B3 K416_F418delinsN somatic mutation, which is a deletion from nucleotides 1248 to 1253. The translated amino acid sequence from 416 to 418, reading as lysine-phenylalanine-phenylalanine, was deleted; however, an asparagine was inserted due to merging of residual nucleotide sequences. The CYP11B2 immunohistochemistry staining demonstrated strong immunoreactivity in this classical adenoma. The ATP2B3 K416_F418delinsN mutation is a functional mutation in APA, since HAC15 cells, a human adrenal cell line, transfected with the mutant gene showed increased CYP11B2 expression and aldosterone production.

Adrenal vein sampling: technique and protocol, a systematic review

Primary aldosteronism is the leading cause of secondary hypertension worldwide. Its deleterious effects outstrip those due to blood pressure elevation alone. An essential part of the work-up of a patient with primary aldosteronism is determining if aldosterone production is unilateral or bilateral. With the former, surgery offers a potential cure and better overall outcomes. Adrenal vein sampling is considered the most reliable method to determine whether production is unilateral or bilateral. Sampling may be non-diagnostic when the vein cannot be properly cannulated. But with proper knowledge and experience as well as the utilization of certain techniques, procedure success can be high. Multiple protocols exist; their rationale and drawbacks are reviewed here. This article will give the reader an overview of techniques for improving procedural success as well as background, rationale and evidence to guide one in choosing the appropriate procedural and interpretation protocol.