Adrenal Venous Sampling: Where Do We Stand?

Selective venous sampling for secondary hypertension

Selective venous sampling (SVS), an invasive radiographic procedure that depends on contrast media, holds a unique role in diagnosing and guiding the treatment of certain types of secondary hypertension, particularly in patients who may be candidates for curative surgery. The adrenal venous sampling (AVS), in particular, is established as the gold standard for localizing and subtyping primary aldosteronism (PA). Throughout decades of clinical practice, AVS could be applied not only to PA but also to other endocrine diseases, such as adrenal Cushing syndrome (ACS) and Pheochromocytomas (PCCs). Notably, the application of AVS in ACS and PCCs remains less recognized compared to PA, with the low success rate of catheterization, the controversy of results interpretation, and the absence of a standardized protocol. Additionally, the AVS procedure necessitates enhancements to boost its success rate, with several helpful but imperfect methods emerging, yet continued exploration remains essential. We also observed renal venous sampling (RVS), an operation akin to AVS in principle, serves as an effective means of diagnosing renin-dependent hypertension, aiding in the identification of precise sources of renin excess and helping the selection of surgical candidates with renin angiotensin aldosterone system (RAAS) abnormal activation. Nonetheless, further basic and clinical research is needed. Selective venous sampling (SVS) can be used in identifying cases of secondary hypertension that are curable by surgical intervention. Adrenal venous sampling (AVS) and aldosterone measurement for classificatory diagnosis of primary aldosteronism (PA) are established worldwide. While its primary application is for PA, AVS also holds the potential for diagnosing other endocrine disorders, including adrenal Cushing's syndrome (ACS) and pheochromocytomas (PCCs) through the measurements of cortisol and catecholamine respectively. In addition, renal venous sampling and renin measurement can help to diagnose renovascular hypertension and reninoma.

Epidemiology and diagnosis of primary aldosteronism. What have we learned from the SPAIN-ALDO registry?

PURPOSE

To summarize the available data on the prevalence, clinical repercussion, and diagnosis of primary aldosteronism (PA) and to discuss the SPAIN-ALDO registry's findings, which is the largest PA patient registry in Spain.

METHODS

A comprehensive review of the literature focused on the prevalence, clinical presentation and diagnosis of PA was performed.

RESULTS

PA is the most common cause of secondary arterial hypertension. In addition, PA patients have a higher cardio-metabolic risk than patients with essential arterial hypertension matched by age, sex, and blood pressure levels. However, despite its high prevalence and associated metabolic and cardiovascular complications, PA remains largely under-recognized, with less than 2% of people in at-risk populations ever tested. The diagnostic investigation is a multistep process, including screening, confirmatory testing, and subtype differentiation of unilateral from bilateral PA forms. Data from the SPAIN-ALDO registry have shed light on the cardiometabolic impact of PA and about the limitations in the PA diagnosis of these patients in Spain.

CONCLUSIONS

The most common cause of secondary hypertension is PA. One of the most challenging aspects of the diagnosis is the differentiation between unilateral and bilateral PA because adrenal venous sampling is a difficult procedure that should be performed in experienced centers. Data from the SPAIN-ALDO registry have provided important information on the nationwide management of this pathology.

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.

Treating Primary Aldosteronism-Induced Hypertension: Novel Approaches and Future Outlooks

Primary aldosteronism (PA) is the most common cause of secondary hypertension and is associated with increased morbidity and mortality when compared with blood pressure-matched cases of primary hypertension. Current limitations in patient care stem from delayed recognition of the condition, limited access to key diagnostic procedures, and lack of a definitive therapy option for nonsurgical candidates. However, several recent advances have the potential to address these barriers to optimal care. From a diagnostic perspective, machine-learning algorithms have shown promise in the prediction of PA subtypes, while the development of noninvasive alternatives to adrenal vein sampling (including molecular positron emission tomography imaging) has made accurate localization of functioning adrenal nodules possible. In parallel, more selective approaches to targeting the causative aldosterone-producing adrenal adenoma/nodule (APA/APN) have emerged with the advent of partial adrenalectomy or precision ablation. Additionally, the development of novel pharmacological agents may help to mitigate off-target effects of aldosterone and improve clinical efficacy and outcomes. Here, we consider how each of these innovations might change our approach to the patient with PA, to allow more tailored investigation and treatment plans, with corresponding improvement in clinical outcomes and resource utilization, for this highly prevalent disorder.

Advances in the molecular imaging of primary aldosteronism

Primary aldosteronism (PA) is the most common cause of secondary hypertension. It predisposes to adverse outcomes such as nephrotoxicity and cardiovascular damage, which are mediated by direct harm from hypertension to the target organs. Accurate subtype diagnosis and localization are crucial elements in choosing the type of treatment for PA in clinical practice since the dominant side of aldosterone secretion in PA affects subsequent treatment options. The gold standard for diagnosing PA subtypes, adrenal venous sampling (AVS), requires specialized expertise, the invasive nature of the procedure and high costs, all of which delay the effective treatment of PA. Nuclide molecular imaging is non-invasive and has wider applications in the diagnosis and treatment of PA. This review aims to provide a summary of the application of radionuclide imaging in the diagnosis, treatment management and prognostic assessment of 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.

Improving the Visualization of the Adrenal Veins Using Virtual Monoenergetic Images from Dual-Energy Computed Tomography before Adrenal Venous Sampling

(1) Background: This study explored the optimal energy level in advanced virtual monoenergetic images (VMI+) from dual-energy computed tomography angiography (DE-CTA) for adrenal veins visualization before adrenal venous sampling (AVS). (2) Methods: Thirty-nine patients were included in this prospective single-center study. The CT value, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in both adrenal veins and abdominal solid organs and were then compared between VMI+ within the range of 40-80 kiloelectron volt (keV). The visualization rate of the adrenal veins and the overall image quality of solid organs were subjectively compared among different keV VMI+. The AVS success rate was recorded for 20 patients. (3) Results: For the adrenal veins, 40 keV VMI+ had the peak CT value, noise and CNR (p < 0.05). Subjectively, the visualization rate was the highest at 40 keV (100% for the right adrenal vein, and 97.4% for the left adrenal vein) (p < 0.05). For solid organs, the CT value, noise and CNR at 50 keV were lower than those at 40 keV (p < 0.05), but the SNR was similar between 40 keV and 50 keV. The overall subjective image quality of solid organs at 50 keV was the best (p < 0.05). The AVS success rate was 95%. (4) Conclusions: For VMI+, 40 keV was the preferential energy level to obtain a high visualization rate of the adrenal veins and a high success rate of AVS, while 50 keV was the favorable energy level for the depiction of abdominal organs.

The Therapeutic Intensity Score as Predictor of Clinical Outcomes after Total and Partial Adrenalectomy for Unilateral Primary Aldosteronism: Results of a Multicentric Series

BACKGROUND

To evaluate the ability of therapeutic intensity score (TIS) in predicting the clinical outcomes of partial (PA) and total adrenalectomy (TA) for UPA.

METHODS

Between 2011 and 2022, a four-center adrenalectomy dataset was queried for "unilateral adrenal mass" and "UPA" (n = 90). Preoperative TIS of each antihypertensive medication were individually calculated and merged to create a single, cumulative variable. Probability of complete clinical, partial, and absent pooled success rates according to TIS were assessed for the overall cohort by Kaplan-Meier. Cox analyses were used to identify predictors of complete clinical and partial/absent success, respectively. For all analyses, a two-sided p < 0.05 was considered significant.

RESULTS

At a median follow-up of 42 months (IQR 27-54) complete partial, and absent clinical success were observed in 60%, 17.7%, and 22.3%, respectively. On Kaplan-Meier analysis, TIS < 1 predicted higher complete success rates (p < 0.001), while TIS ≥ 1 was predictor of either partial and absent clinical success (p = 0.008). On multivariable analysis, TIS < 1 (HR 0.25; 95% CI 0.11-0.57; p = 0.001) and adenoma size (HR 1.11; 95% CI 1-1.23; p = 0.0049) were independent predictors of complete clinical success, while TIS ≥ 1 (HR 2.84; 95% CI 1.32-6.1; p = 0.007) was the only independent predictor of absent clinical success.

CONCLUSIONS

TIS score and adenoma size may help to identify patients who are likely to be at risk of persistent hypertension after surgery.

Influence of cortisol cosecretion on non-ACTH-stimulated adrenal venous sampling in primary aldosteronism: a retrospective cohort study

OBJECTIVE

Cortisol measurements are essential for the interpretation of adrenal venous samplings (AVS) in primary aldosteronism (PA). Cortisol cosecretion may influence AVS indices. We aimed to investigate whether cortisol cosecretion affects non-adrenocorticotrophic hormone (ACTH)-stimulated AVS results.

DESIGN

Retrospective cohort study at a tertiary referral center.

METHODS

We analyzed 278 PA patients who underwent non-ACTH-stimulated AVS and had undergone at least a 1-mg dexamethasone suppression test (DST). Subsets underwent additional late-night salivary cortisol (LSC) and/or 24-h urinary free cortisol (UFC) measurements. Patients were studied from 2013 to 2020 with follow-up data of 6 months following adrenalectomy or mineralocorticoid antagonist therapy initiation. We analyzed AVS parameters including adrenal vein aldosterone/cortisol ratios, selectivity, lateralization (LI) and contralateral suppression indices and post-operative ACTH-stimulation. We classified outcomes according to the primary aldosteronism surgical outcome (PASO) criteria.

RESULTS

Among the patients, 18.9% had a pathological DST result (1.9-5 µg/dL: n = 44 (15.8%); >5 µg/dL: n = 8 (2.9%)). Comparison of AVS results stratified according to the 1-mg DST (≤1.8 vs >1.8 µg/dL: P = 0.499; ≤1.8 vs 1.8 ≤ 5 vs >5 µg/dL: P = 0.811) showed no difference. Lateralized cases with post DST serum cortisol values > 5 µg/dL had lower LI (≤1.8 µg/dL: 11.11 (5.36; 26.76) vs 1.9-5 µg/dL: 11.76 (4.9; 31.88) vs >5 µg/dL: 2.58 (1.67; 3.3); P = 0.008). PASO outcome was not different according to cortisol cosecretion.

CONCLUSIONS

Marked cortisol cosecretion has the potential to influence non-ACTH-stimulated AVS results. While this could result in falsely classified lateralized cases as bilateral, further analysis of substitutes for cortisol are required to unmask effects on clinical outcome.

Adrenal venous sampling in primary aldosteronism: Experience of a Spanish multicentric study (Results from the SPAIN-ALDO Register)

OBJECTIVE

The aim of this study was to evaluate the rate of adrenal venous sampling (AVS) performance in patients with primary aldosteronism (PA), the main reasons for its non-performance, and the success and complications rate of this procedure in Spain. Moreover, the concordance between CT/MRI and AVS for PA subtyping was evaluated.

METHODS

A retrospective multicenter study of PA patient follow-up in 20 Spanish tertiary hospitals between 2018-2021 was performed (SPAIN-ALDO Register).

RESULTS

Of the 440 patients with PA included in the study, 153 underwent AVS (34.8%). The main reasons for not performing AVS were: patient rejection to the procedure, low catheterization rate in the center and unilateral disease based on CT/MRI. The overall success rate was 44.4% (the left adrenal vein was properly canulated in 77.8% and the right adrenal vein in 48.4%). Only 3 patients experienced minor complications. In the 45 patients with unilateral disease according to AVS, CT/MRI indicated bilateral disease or normal adrenal glands in 17. In the 23 patients with bilateral disease, CT/MRI indicated unilateral disease in 14. However, no significant differences were observed in biochemical response (P = 0.051) and hypertension resolution (P = 0.150) between patients who underwent surgery based on CT/MRI results and those who underwent surgery based on AVS results.

CONCLUSION

In our setting, AVS is still an underused technique in patients with PA. The low experience and success rate in AVS partially justify these results. More training for providers and patients needs to be done to include appropriate well performed AVS in the diagnosis algorithm of 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.

Surgical Quality, Antihypertensive Therapy, and Electrolyte Balance: A Novel Trifecta to Assess Long-Term Outcomes of Adrenal Surgery for Unilateral Primary Aldosteronism

BACKGROUND

To propose a trifecta that summarizes endpoints and predicts their maintenance after adrenalectomy (n = 90) for unilateral primary aldosteronism (UPA).

METHODS

Trifecta was defined as coexistence of: ≥50% antihypertensive therapeutic intensity score reduction (∆TIS), no hypokalemia at 3 months, and no Clavien grade 2-5. Logistic regression was used to identify predictors of trifecta. Probability of clinical, biochemical, and simultaneous success according to trifecta were assessed by Kaplan-Meier. Cox regression was used to identify predictors of long-term clinical, biochemical, and simultaneous success. For all analyses, a two-sided p < 0.05 was considered significant.

RESULTS

Simultaneous success rate was 50%. On multivariable analysis, TIS was an independent predictor of trifecta achievement (HR 3.28; 95% CI 1.07-10.9; p = 0.03). At Kaplan-Meier, trifecta predicted higher success for all endpoints (each p < 0.03). On multivariable Cox analysis, adenoma size (AS) ≥6 cm and trifecta were independent predictors of biochemical (AS: HR 2.87; 95% CI 1.53-5.36; trifecta: HR 2.1; 95% CI 1.13-3.90; each p < 0.02) and simultaneous success (AS: HR 3.81; 95% CI 1.68-8.65; trifecta: HR 4.29; 95% CI 2.08-8.86; each p < 0.01), while trifecta was an independent predictor of complete clinical success (HR 2.84; 95% CI 1.45-5.58; p < 0.01).

CONCLUSIONS

Trifecta and AS are independent predictors of either long-term complete clinical, biochemical, or combined success after adrenalectomy for UPA.

Adrenal Vein Sampling in Primary Aldosteronism: A Pictorial Essay for Optimal Left-Side Sampling

Primary aldosteronism (PA) is a curable cause of hypertension. Recent studies have revealed that the actual prevalence of PA is higher than previously recognized. Adrenal vein sampling (AVS) is an essential diagnostic procedure for revealing the cause of PA and determining the treatment plan. The success of AVS is confirmed by comparing cortisol levels between the samples from each adrenal vein and peripheral vein. The failure rate of the procedure is reported to be high in the right adrenal vein, which is directly connected to the inferior vena cava, while that in the left adrenal vein is relatively low; however, this has rarely been reported. In this review, we introduce and analyze cases of failure in left adrenal vein sampling.

Diagnosis of primary hyperaldosteronism

Primary aldosteronism (PA) is the most common cause of secondary arterial hypertension. Moreover, it is associated with a higher cardio-metabolic risk than the observed in patients with essential arterial hypertension (EHT). Therefore, a high index of clinical suspicion for PA is mandatory. If an elevated aldosterone/renin ratio is confirmed, confirmatory tests should be performed, with the exception in those patients with florid PA, with, with spontaneous hypokalaemia, plasma aldosterone > 20 ng/dL and suppressed renin, in whom this step would not be strictly necessary. Intravenous saline infusion test or captopril test are the commonly used confirmatory tests. The last step in the diagnosis of PA is the localization study, being the computerized axial tomography (CT) of the adrenal glands the initial test of choice, and adrenal venous sampling (AVS), the definitive localization test in most cases. This review summarizes the available data about the diagnosis of PA, from screening to confirmatory study and localization.

Adrenal Vein Sampling in a Patient With Primary Hyperaldosteronism and Severe Contrast Allergy

We report on a case of a 50-year-old female patient with primary hyperaldosteronism, in whom adrenal venous sampling was required to differentiate between unilateral and bilateral disease. Because of a history of severe allergy to iodinated contrast media, premedication with glucocorticoids was indicated. Exogenous glucocorticoids, however, can affect measurements of serum cortisol. To avoid this potential confounding effects on the cortisol assay, we decided to use dexamethasone instead of prednisolone or hydrocortisone. A high-dose adrenocorticotropin (ACTH) stimulation test with the simultaneous use of dexamethasone revealed an adequate adrenal cortisol response. ACTH-stimulated adrenal venous sampling showed reliable results, which provided a solid basis for further clinical decision-making.