Adrenal Venous Sampling

Determination of adrenal hypersecretion in primary Aldosteronism without aldosterone-production adenomas

BACKGROUND

Primary aldosteronism (PA) is highly prevalent in hypertensive population. Adrenal vein sampling (AVS) is the only procedure to assess adrenal aldosterone hypersecretion in PA. PA patients without aldosterone-producing adenomas (APA) frequently have unilateral aldosterone hypersecretion (UAH). These patients could bear inappropriate adrenalectomy without AVS. This study aims to identify which clinical characteristics should be recommended to perform AVS in these PA patients.

METHODS

This study was performed from January 2018 to July 2019 at a center for hypertension and metabolic diseases. Adrenal computed tomography (CT) scan, biochemical evaluation, and AVS were performed.

RESULTS

Total 141 patients were included in this study. Aldosterone to renin ratio (ARR) after confirmatory test is highly associated with adrenal laterality. The specificity of ARR > 10 (ng/dL)/(mU/L) after confirmatory test is 100%. After confirmatory test, patients with ARR > 10 (ng/dL)/(mU/L) had higher plasma aldosterone concentration and incidences of ischemic heart diseases and renal damage(p < 0.05).

CONCLUSIONS

After confirmatory tests, ARR > 10 (ng/dL)/(mU/L) indicates adrenal laterality, with increasingly cardiorenal damage in PA patients without APA. Thus, AVS should be recommended in these patients before surgery.

TRIAL REGISTRATION

NCT03398785 , Date of Registration: December 24, 2017.

Computed tomography image fusion, Coaxial guidewire technique, Fast intraprocedural cortisol testing technique improves success rate and decreases radiation exposure, procedure time, and contrast use for adrenal vein sampling

BACKGROUND

Adrenal vein sampling (AVS) is recommended for discriminating patients with unilateral primary aldosteronism from bilateral disease. However, it is a technically demanding procedure that is markedly underused. We developed a computed tomography image fusion, coaxial guidewire technique, fast intraprocedural cortisol testing (CCF) technique to improve AVS success rate, which combines CT image fusion, coaxial guidewire technique, and fast intraprocedural cortisol testing.

OBJECTIVE

To evaluate the effectiveness and safety of the AVS--CCF technique.

METHODS

We retrospectively evaluated 105 patients who undervent AVS from June 2016 to October 2020. There were 51 patients in the AVS--CCF group and 54 patients in the AVS group. We compared two groups with technical success rate, procedure time, radiation exposure, volume of contrast medium, and complications (adrenal vein rupture, dissection, infarction, or thrombosis; intraglandular or periadrenal hematoma; and contrast-induced nephropathy).

RESULTS

The technical success rate was higher for AVS--CCF than for AVS without CCF (98 vs. 83.3% for bilateral adrenal veins, P = 0.016). AVS--CCF was associated with a shorter procedure time (63.6 ± 24.6 vs. 94.8 ± 40.8 min, P < 0.001), shorter fluoroscopy time (15.6 ± 12.6 vs. 20.4 ± 15.0 min, P = 0.043), and lower contrast medium volume (25.10 ± 21.82 vs. 44.1 ± 31.0 ml, P < 0.001). There were no significant differences between groups with respect to the time for cannulating the left or right adrenal vein or the peak skin radiation dose. Adrenal vein rupture occurred in 14 patients and intraglandular hematoma in 1 patient.

CONCLUSION

The CCF technique during AVS not only contributed to improved technical success rates but also associated with decreased procedure time, radiation exposure, and contrast medium volume.

Aldosterone-potassium ratio predicts primary aldosteronism subtype

OBJECTIVE

Prediction models have been developed to predict either unilateral or bilateral primary aldosteronism, and these have not been validated externally. We aimed to develop a simplified score to predict both subtypes and validate this externally.

METHODS

Our development cohort was taken from 165 patients who underwent adrenal vein sampling (AVS) in two Asian tertiary centres. Unilateral disease was determined using both AVS and postoperative outcome. Multivariable analysis was used to construct prediction models. We validated our tool in a European cohort of 97 patients enrolled in the SPARTACUS trial who underwent AVS. Previously published prediction models were also tested in our cohorts.

RESULTS

Backward stepwise logistic regression analysis yielded a final tool using baseline aldosterone-to-lowest-potassium ratio (APR, ng/dl/mmol/l), with an area under receiver-operating characteristic curve of 0.80 (95% CI 0.70-0.89). In the Asian development cohort, probability of bilateral disease was 90.0% (with APR <5) and probability of unilateral disease was 91.4% (with APR >15). Similar results were seen in the European validation cohort. Combining both cohorts, probability of bilateral disease was 76.7% (with APR <5), and probability for unilateral was 91.7% (with APR >15). Other models had similar predictive ability but required more variables, and were less sensitive for identifying bilateral PA.

CONCLUSION

The novel aldosterone-to-lowest-potassium ratio is a convenient score to guide clinicians and patients of various ethnicities on the probability of primary aldosteronism subtype. Using APR to identify patients more likely to benefit from AVS may be a cost-effective strategy to manage this common condition.

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.

Approach to the Patient with Primary Aldosteronism: Utility and Limitations of Adrenal Vein Sampling

Several studies over the past 3 decades document a higher prevalence of primary aldosteronism (PA) among hypertensive patients than generally presumed. PA exists as a spectrum from mild to severe aldosterone excess. Although a variety of PA subtypes exist, the 2 most common are aldosterone-producing adenomas (APAs) and bilateral hyperaldosteronism (BHA). The distinction is important, because APA-and other subtypes, with aldosterone production mostly from 1 adrenal-can be cured surgically, and BHA should be treated medically with mineralocorticoid-receptor antagonists (MRAs). The major shortcomings in the tailored management of patients with possible PA are the low rates of screening for case identification and the expensive and technically challenging imaging and interventional procedures required to distinguish APA from BHA, especially adrenal vein sampling (AVS). When AVS identifies an APA and allows the patient to be cured surgically, the procedure is of great value. In contrast, the patient with BHA is treated with MRA whether AVS is performed or not. Consequently, it is prudent to gauge how likely it is to benefit from imaging and AVS in each case prior to embarking on these studies. The explosion of information about PA in the past decade, including predictors of APA and of surgical benefit, are useful in limiting the evaluation for some patients with a positive PA screening test. This article will review our suggestions for approaching these patients in a pragmatic style, recognizing the limitations to even the best resources and facilities.

Association of Adrenal Venous Sampling With Outcomes in Primary Aldosteronism for Unilateral Adenomas

Importance

Adrenal venous sampling is recommended prior to adrenalectomy for all patients with hyperaldosteronism; however, cross-sectional imaging resolution continues to improve, while the procedure remains invasive and technically difficult. Therefore, certain patients may benefit from advancing straight to surgery.

Objective

To determine whether clinical and biochemical resolution varied for patients with primary aldosteronism with unilateral adenomas who underwent adrenal venous sampling vs those who proceeded to surgery based on imaging alone.

Design, Setting, and Participants

Retrospective, international cohort study of patients treated at 3 tertiary medical centers from 2004 to 2019, with a median follow-up of approximately 6 months. A total of 217 patients were consecutively enrolled. Exclusion criteria consisted of unknown postoperative serum aldosterone level and imaging inconsistent with unilateral adenoma with a normal contralateral gland. A total of 125 patients were included in the analysis. Data were analyzed between October 2019 and July 2020.

Exposures

Adrenal venous sampling performed preoperatively.

Main Outcomes and Measures

The primary outcome measurements were the clinical and biochemical success rates of surgery for the cure of hyperaldosteronism secondary to aldosterone-producing adenoma.

Results

A total of 125 patients were included (45 cross-sectional imaging with adrenal venous sampling and 80 imaging only). The mean (SD) age of the study participants was 50.2 (10.6) years and the cohort was 42.4% female (n = 53). Of those patients for whom race or ethnicity were reported (n = 80), most were White (72.5%). Adrenal venous sampling failure rate was 16.7%, and the imaging concordance rate was 100%. Relevant preoperative variables were similar between groups, except ambulatory systolic blood pressure, which was higher in the imaging-only group (150 mm Hg; interquartile range [IQR], 140-172 mm Hg vs 143 mm Hg, IQR, 130-158 mm Hg; P = .03). Resolution of autonomous aldosterone secretion was attained in 98.8% of imaging-only patients and 95.6% of adrenal venous sampling patients (P = .26). There was no difference in complete clinical success (43.6% [n = 34] vs 42.2% [n = 19]) or partial clinical success (47.4% [n = 37] vs 51.1% [n = 23]; P = .87) between groups. Complete biochemical resolution was similar as well (75.9% [n = 41] vs 84.4% [n = 27]; P = .35). There was no difference in clinical or biochemical cure rates when stratified by age, although complete clinical success rates downtrended in the older cohorts, and sample sizes were small.

Conclusions and Relevance

Given the improved sensitivity of cross-sectional imaging in detection of adrenal tumors, adrenal venous sampling may be selectively performed in appropriate patients with clearly visualized unilateral adenomas without affecting outcomes. This may facilitate increased access to surgical cure for aldosterone-producing adenomas and will decrease the incidence of morbidities associated with the procedure.

Feasibility and effectiveness of a single-catheter approach for adrenal vein sampling in patients with primary aldosteronism

BACKGROUND

Adrenal vein sampling (AVS) is the preferred method for subtyping patients with primary aldosteronism, while the procedure is technically challenging. This study evaluated the feasibility and effectiveness of a single-catheter approach for AVS.

METHODS

A retrospective analysis of 106 consecutive patients who underwent AVS was performed to determine the procedural success and complication rates. Bilateral AVS procedures were performed using a single 5-Fr Tiger catheter with repeated manual reshaping.

RESULTS

We successfully advanced the catheter into the bilateral adrenal veins of all patients and reached a 90.6% procedural success rate of AVS. The procedural period was 33.0 ± 8.2 min, the fluoroscopy period was 5.8 ± 1.7 min, and the diagnostic contrast used was 17.3 ± 5.5 ml. Only one patient (0.9%) had a hematoma at the femoral puncture site. No other complications were observed. The operation period gradually shortened as the cumulative number of operations increased. The number of procedures required to overcome the learning curve was about 33 cases.

CONCLUSIONS

The single-catheter approach is feasible and effective for AVS. Moreover, this approach required a relatively short learning curve for an inexperienced trainee.

Adrenalectomy for Primary Aldosteronism: Significant Variability in Work-Up Strategies and Low Guideline Adherence in Worldwide Daily Clinical Practice

BACKGROUND

Various diagnostic tests are available to establish the primary aldosteronism (PA) diagnosis and to determine the disease laterality. Combined with the controversies in the literature, unawareness of guidelines and technical demands and high costs of some of these diagnostics, this could lead to significant differences in work-up strategies worldwide. Therefore, we investigated the work-up before surgery for PA in daily clinical practice within a multicenter study.

METHODS

Patients who underwent unilateral adrenalectomy for PA within 16 centers in Europe, Canada, Australia and the USA between 2010 and 2016 were included. We did not exclude patients based on the performed diagnostic tests during work-up to make our data representative for current clinical practice. Adherence to the Endocrine Society Guideline and variables associated with not performing adrenal venous sampling (AVS) were analyzed.

RESULTS

In total, 435 patients were eligible. An aldosterone-to-renin ratio, confirmatory test, computed tomography (CT), magnetic resonance imaging and AVS were performed in 82.9%, 32.9%, 86.9%, 17.0% and 65.3% of patients, respectively. A complete work-up, as recommended by the guideline, was performed in 13.1% of patients. Bilateral disease or normal adrenal anatomy on CT (OR 16.19; CI 3.50-74.99), smaller tumor size on CT (OR 0.06; CI 0.04-0.08) and presence of hypokalemia (OR 2.00; CI 1.19-3.32) were independently associated with performing AVS.

CONCLUSIONS

This study is the first to examine the daily clinical practice work-up of PA within a worldwide cohort of surgical patients. The results demonstrate significant variability in work-up strategies and low adherence to The Endocrine Society guideline.

Functional Characteristic and Significance of Aldosterone-Producing Cell Clusters in Primary Aldosteronism and Age-Related Hypertension

Primary aldosteronism (PA) is one of the most frequent curable forms of secondary hypertension. It can be caused by the overproduction of aldosterone in one or both adrenal glands. The most common subtypes of PA are unilateral aldosterone over-production due to aldosterone-producing adenomas (APA) or bilateral aldosterone over-production due to bilateral hyperaldosteronism (BHA). Utilizing the immunohistochemical (IHC) detection of aldosterone synthase (CYP11B2) has allowed the identification of aldosterone-producing cell clusters (APCCs) with unique focal localization positive for CYP11B2 expression in the subcapsular portion of the human adult adrenal cortex. The presence of CYP11B2 supports that synthesis of aldosterone can occur in these cell clusters and therefore might contribute to hyperaldosteronism. However, the significance of the steroidogenic properties of APCCs especially in regards to PA remains unclear. Herein, we review the available evidence on the presence of APCCs in normal adrenals and adrenal tissues adjacent to APAs, their aldosterone-stimulating somatic gene mutations, and their accumulation during the ageing process; raising the possibility that APCCs may play a role in the development of PA and age-related hypertension.

Update: Selective adrenal venous sampling (AVS) - Indication, technique, and significance

BACKGROUND

 Primary aldosteronism (PA) is the most common detectable cause of secondary hypertension. The majority of patients have either an adrenal aldosterone-producing adenoma (APA) or bilateral adrenal hyperplasia (BAH) demanding different therapeutic approaches. Screening tests and imaging cannot reliably distinguish between a unilateral or bilateral PA.

METHODS

 This review article gives an overview concerning etiology, diagnostics, and therapeutic options of PA, and reviews the indication, the technique, and relevance of selective adrenal venous sampling (AVS) in the context of the current literature and the authors' experience.

RESULTS

 AVS can verify or exclude a unilaterally dominated secretion with a high success rate. Patients with PA and a unilateral APA can be treated curatively by adrenalectomy.

CONCLUSIONS

 AVS is an established diagnostic examination for differentiation of unilateral from bilateral adrenal disease in patients with PA.

KEY POINTS

· Selective adrenal venous sampling (AVS) is a safe, reliable, and minimally invasive method to detect a unilateral or bilateral adrenal adrenal gland disease.. · Verification of lateralization by AVS has direct therapeutic relevance for patients with primary aldosteronism (PA).. · AVS can be performed with low radiation exposure, without contrast medium, and with a high success rate when performed by an experienced interventional radiologist..

CITATION FORMAT

· Loberg C, Antoch G, Stegbauer J et al. Update: Selective adrenal venous sampling (AVS) - Indication, technique, and significance. Fortschr Röntgenstr 2021; 193: 658 - 666.

131I-6β-iodomethyl-19-norcholesterol adrenal scintigraphy as an alternative to adrenal venous sampling in differentiating aldosterone-producing adenoma from bilateral idiopathic hyperaldosteronism

OBJECTIVE

To assess the correlation value between adrenal venous sampling (AVS) and I-6β-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy in differentiating aldosterone-producing adenoma (APA) from bilateral idiopathic hyperaldosteronism (BHA), and the use of NP-59 scintigraphy as an alternative to AVS.

METHODS

Overall, 29 patients with APA or BHA who underwent AVS and dexamethasone-suppression NP-59 scintigraphy were included between 2010 and 2017. The correlation value between AVS and dexamethasone-suppression NP-59 scintigraphy was assessed using each lateralisation index (LIAVS and LI1NP-59). Tumour presence and size were evaluated using computed tomography. The sensitivity and specificity of dexamethasone-suppression NP-59 scintigraphy for APA according to each lateralisation index threshold were calculated.

RESULTS

Of 29 patients, 12 presented with APA and 17 with BHA according to AVS. The correlation value between LIAVS and LI1NP-59 was 0.63 (P < 0.001). If the cut-off points were 2.55 and 1.80 in all cases, the sensitivity and specificity were 0.33 and 1.00 as well as 0.58 and 0.94, respectively. In adrenal microtumours (maximum diameter ≤10 mm), no cases revealed a cut-off point of >1.8. However, in adrenal macrotumours (maximum diameter >10 mm), the cut-off point of 2.55 represented the best compromise (sensitivity: 0.44; specificity: 1.00).

CONCLUSION

NP-59 scintigraphy can be used as an alternative to AVS if there is a strong lateralisation on NP-59 scintigraphy and adrenal macrotumours observed on the computed tomography when AVS is technically challenging, particularly in the right adrenal vein cannulation, and if contraindications, such as allergy to contrast materials and renal failure, are observed.

Adrenal vein sampling: External validation of multinomial regression modelling and left adrenal vein-to-peripheral vein ratio to predict lateralization index without right adrenal vein sampling

BACKGROUND

Adrenal vein sampling (AVS) failure is mainly due to right adrenal vein unavailability. Multinomial regression modelling (MRM) and left adrenal vein-to-peripheral vein ratio (LAV/PV) were proposed to predict the lateralization index without the right AVS.

OBJECTIVE

To assess external validity of MRM and LAV/PV to predict lateralization index when right adrenal vein sampling is missing.

DESIGN

Diagnostic retrospective study.

PATIENTS

Development and validation cohorts included AVS of 174 and 122 patients, respectively, from 2 different centres.

MEASUREMENTS

Development and validation cohort data were used, respectively, for calibration and for validation of MRM and LAV/PV to predict the lateralization index without the right adrenal vein sampling. Sensitivity and specificity of MRM and LAV/PV were compared between both centres at different pre-established specificity thresholds based on receiver operating characteristic curves generated from the development cohort data.

RESULTS

At a specificity threshold of 95% set in the development cohort, specificity values exceeded 90% (range, 90.6%-98.8%) for all verified MRM and LAV/PV models in the validation cohort. Corresponding sensitivities for MRM and LAV/PV, respectively, range from 54.1% to 83.7% and 32.8% to 88.4% for the development cohort compared to 33.3%-87.5% and 2.8%-79.2% for the validation cohort. Overall, diagnostic accuracy of both methods was higher to detect right (82.8%-93.5%) than left (70.2%-80.6%) lateralization index status in both centres.

CONCLUSIONS

Minimal changes in specificity from development to validation cohorts validate the use of MRM and LAV/PV to predict the lateralization index when the right AVS is missing. Both methods had better accuracy for right than left lateralization detection.

The diagnostic accuracy of adjusted unconventional indices for adrenal vein sampling in the diagnosis of primary aldosteronism subtypes

OBJECTIVE

Simple unconventional indices did not demonstrate a satisfactory accuracy for diagnosing unilateral primary aldosteronism when adrenal vein sampling is not bilaterally selective. This study aimed to evaluate the reliability of clinical/imaging-corrected unconventional indices for adrenal vein sampling in predicting unilateral primary aldosteronism.

METHODS

Data of all consecutive patients with primary aldosteronism subtyped with adrenal vein sampling, referred to two Italian centers, were analyzed retrospectively. All patients with proved unilateral aldosterone hypersecretion underwent adrenalectomy.

RESULTS

Unilateral disease was diagnosed in 58 cases (54.2%) and idiopathic hyperaldosteronism in 49 individuals (45.8%). The monoadrenal index (aldosterone-to-cortisol ratio in the adrenal vein) showed high accuracy in predicting ipsilateral disease and moderate accuracy in predicting contralateral aldosterone hypersecretion. The monolateral index (aldosterone-to-cortisol ratio in the adrenal vein vs. peripheral blood) revealed moderate accuracy in predicting ipsilateral disease and high accuracy in predicting contralateral aldosterone hypersecretion. Lesion side- and hypokalemia-corrected ROC curves for these unconventional indices revealed a significant improvement in the reliability of predicting ipsilateral/contralateral disease, reaching high accuracy in all models. For an immediate clinical application of our results, the adjusted cut-offs were calculated, according to the Youden's criterion and to a pre-established specificity of 95%, for all possible combinations of lesion side at imaging and presence/absence of hypokalemia.

CONCLUSION

This study demonstrated the high diagnostic accuracy of clinical-/imaging-corrected unconventional indices for adrenal vein sampling in the diagnosis of primary aldosteronism subtypes and suggests the use of these adjusted indices to select patients for adrenalectomy when adrenal vein sampling is not bilaterally selective.

Treatment of primary hyperaldosteronism

Primary aldosteronism is associated with higher cardiovascular and renal morbidity and mortality than essential hypertension in age- and sex-matched patients with the same degree of blood pressure elevation. Therefore, it is essential to establish a specific treatment to avoid the deleterious effects of aldosterone excess. Although adrenalectomy is generally considered the treatment of choice in cases of primary aldosteronism due to unilateral disease, several aspects and circumstances should be taken into account that may make medical treatment more appropriate. Among them, in this review we mention the limited experience and efficacy, and the potential risks of adrenal vein sampling; the risks and low efficacy of adrenalectomy; the high safety and efficacy of medical treatment and some special situations such as primary aldosteronism during pregnancy, in patients of advanced age or hereditary forms of primary aldosteronism, in which medical treatment is considered especially indicated as the first line therapy. The main studies comparing medical and surgical treatment in primary aldosteronism are also discussed.

The role of adrenal venous sampling and computed tomography in the management of primary aldosteronism

BACKGROUND

The role of adrenal venous sampling (AVS) has been challenged by some recent evidence. This study aimed to compare the role of AVS and computed tomography (CT) in the management of primary aldosteronism.

METHODS

Patients who underwent unilateral adrenalectomy for primary aldosteronism at a single center between January 2015 and December 2018 were included, and postoperative outcomes of the patients who underwent surgery based on CT (n = 195) or AVS (n = 40) were compared. The data of all the patients who underwent AVS successfully (n = 75) during this period were also collected and analyzed.

RESULTS

There were no significant differences between the CT-guided and AVS-guided adrenalectomies in most of the postoperative outcomes, and the proportion of patients achieving cure of hypokalemia (CT vs. AVS, 98.3 vs. 96.4%) and alleviation of hypertension (89.2 vs. 92.9%) were similar between the two groups. However, since the baseline characteristics of the two groups were not identical, the AVS-guided group showed greater improvement in postoperative hypokalemia and greater reduction in the number of antihypertensive medications than the CT-guided group. In addition, for the 75 patients who underwent AVS successfully, the concordance rate between CT abnormalities and AVS lateralization was 60.0% in total, and 22.7% patients changed treatment plans according to the AVS results.

CONCLUSION

Although the clinical outcomes were not significantly different between the CT-guided and AVS-guided group, the AVS-guided group seemed to benefit more from the surgery, and a considerable number of patients with primary aldosteronism would have received inappropriate treatment if they did not undergo AVS.

Adrenal vein sampling for primary aldosteronism: a 15-year national referral center experience

Background

Adrenal vein sampling (AVS) is essential for diagnostics of primary aldosteronism, distinguishing unilateral from bilateral disease and determining treatment options. We reviewed the performance of AVS for primary aldosteronism at our center during first 15 years, comparing the initial period to the period after the introduction of a dedicated radiologist. Additionally, AVS outcomes were checked against CT findings and the proportion of operated patients with proven unilateral disease was estimated.

Patients and methods

A retrospective cross-sectional study conducted at the national endocrine referral center included all patients with primary aldosteronism who underwent AVS after its introduction in 2004 until the end of 2018. AVS was performed sequentially during Synacthen infusion. When the ratio of cortisol concentrations from adrenal vein and inferior vena cava was at least 5, AVS was considered successful.

Results

Data from 235 patients were examined (168 men; age 32–73, median 56 years; BMI 18–48, median 30.4 kg/ m²). Average number of annual AVS procedures increased from 7 in the 2004–2011 period to 29 in the 2012–2018 period (p < 0.001). AVS had to be repeated in 10% of procedures; it was successful in 77% of procedures and 86% of patients. The proportion of patients with successful AVS (92% in 2012–2018 vs. 66% in 2004–2011, p < 0.001) and of successful AVS procedures (82% vs. 61%, p < 0.001) was statistically significantly higher in the recent period.

Conclusions

Number of AVS procedures and success rate at our center increased over time. Introduction of a dedicated radiologist and technical advance expanded and improved the AVS practice.

Bilateral Aldosterone Suppression in Patients With Right Unilateral Primary Aldosteronism and Review of the Literature

Introduction

Adrenal vein sampling (AVS) identifies unilateral primary aldosteronism but may occasionally show paradoxically low aldosterone–cortisol ratios bilaterally. Postulated reasons include venous anomalies, fluctuating aldosterone secretion, or superselective cannulation. We report our findings in patients who underwent repeat AVS and reviewed the current literature.

Methods

We performed a retrospective observational study of patients undergoing AVS in an experienced high-volume tertiary center over a 5-year period.

Results

From 2015 to 2019, 61 patients underwent sequential cosyntropin-stimulated AVS and all had bilateral successful cannulation (100%). Four of 61 (6.6%) patients had bilaterally low aldosterone–cortisol ratios. Three patients underwent repeat AVS, with all 3 cases demonstrating right-sided lateralization and cure of disease postadrenalectomy. Right-sided disease was also more common in other reports. This may be due to inadvertent superselective cannulation of the short right adrenal vein, resulting in sampling of the adjacent normal gland. Cortisol results cannot detect this problem. In 1 patient, computed tomography venography excluded any accessory right adrenal veins. In another patient, repeat bilateral simultaneous unstimulated AVS was done, and measurements of metanephrines aided in accurately identifying right-sided lateralization.

Conclusion

In addition to technical difficulties in cannulating the right adrenal vein, we also have to avoid performing superselective cannulation inadvertently. In cases of inconclusive AVS, repeat sampling may identify patients with potentially curable unilateral primary aldosteronism. The role of corticotropin stimulation and metanephrines measurements during repeat AVS requires further study.

Improved Visualization and Identification of the Right Adrenal Vein in 70-kVp Contrast-Enhanced Computed Tomography

OBJECTIVE

The aim of this study was to assess the utility of 70-kilovoltage-peak (kVp) contrast-enhanced computed tomography (CECT) for visualization and identification of the right adrenal vein (RAV) in comparison with that of conventional 120-kVp CECT.

METHODS

This retrospective study included patients who underwent adrenal venous sampling with concurrent biphasic 120-kVp (120-kVp group, n = 43) or 70-kVp (70-kVp group, n = 47) CECT. Signal-to-noise ratios, contrast-to-noise ratios, longitudinal lengths, conspicuity scores, RAV detection rates, and size-specific dose estimates were compared between the 2 groups.

RESULTS

In comparison with the 120-kVp group, the 70-kVp group had significantly higher signal-to-noise and contrast-to-noise ratios (P < 0.001-P = 0.033), greater longitudinal lengths (P < 0.001-P = 0.002), superior conspicuity scores for the RAV (P < 0.001), higher RAV detection rates (P = 0.015-P = 0.033), and lower size-specific dose estimates (P < 0.001).

CONCLUSIONS

Seventy-kilovoltage-peak CECT has advantages over conventional 120-kVp CECT and is potentially useful for noninvasive assessment of the precise anatomy of the RAV.

Can incomplete adrenal venous sampling data be used in predicting the subtype of primary aldosteronism?

BACKGROUND

Adrenal venous sampling (AVS) is the gold standard for preoperative differentiation between unilateral and bilateral primary aldosteronism (PA). However, results are sometimes vitiated by failing to access the right adrenal vein.

MATERIALS AND METHODS

The present study assumed that clinical decisions can be made with incomplete AVS data, by comparing aldosterone/cortisol (A/C) ratio in both left and right adrenal veins with that in the inferior vena cava (LAV/IVC and RAV/IVC). Receiver operation characteristic (ROC) curve and scatterplot were used to certify the upper and lower cutoffs and to analyze the significance of discrimination. One hundred and sixty patients diagnosed with PA from April 2017 to June 2018 underwent AVS in the Urology Department of West China Hospital, Chengdu, China. One hundred and eleven with complete AVS data were divided into 3 groups: left-sided (N=40), right-sided (N=29) and bilateral (N=42). We also collected patients from September 2018 to April 2019 in our department as validation cohort to test our hypothesis.

RESULTS

On the basis of LAV/IVC, RAV/IVC and diagnostic category, upper cutoff was 1.14 (50% sensitivity and 100% specificity) and lower cutoff 0.07 (27.5% sensitivity and 100% specificity) for LAV/IVC, and 1.04 (55% sensitivity and 100% specificity) and 0.08 (40% sensitivity and 100% specificity), respectively, for RAV/IVC.

CONCLUSION

The diagnostic model in this study contributes to clinical decision-making in patients with only partial PA with incomplete AVS data.

Steroid Profiling and Immunohistochemistry for Subtyping and Outcome Prediction in Primary Aldosteronism-a Review

PURPOSE OF REVIEW

Steroid profiling and immunohistochemistry are both promising new tools used to improve diagnostic accuracy in the work-up of primary aldosteronism (PA) and to predict treatment outcomes. Herein, we review the recent literature and present an outlook to the future of diagnostics and therapeutic decision-making in patients with PA.

RECENT FINDING

PA is the most common endocrine cause of arterial hypertension and unilateral forms of the disease are potentially curable by surgical resection of the overactive adrenal. Recent studies have shown that adrenal steroid profiling by liquid chromatography-tandem mass spectrometry (LC-MS/MS) can be helpful for subtyping unilateral and bilateral forms of PA, classifying patients with a unilateral aldosterone-producing adenoma (APA) according to the presence of driver mutations of aldosterone production in APAs, and potentially predicting the outcomes of surgical treatment for unilateral PA. Following adrenalectomy, immunohistochemistry of aldosterone synthase (CYP11B2) in resected adrenals is a new tool to analyze "functional" histopathology and may be an indicator of biochemical outcomes after surgery. Biochemical and clinical outcomes of therapy in PA vary widely among patients. Peripheral venous steroid profiling at baseline could improve diagnostic accuracy and help in surgical decision-making in cases of a suspected APA; results of "functional" histopathology could help determine which patients are likely to need close post-surgical follow-up for persistent aldosteronism.

Clinical Outcomes of 1625 Patients With Primary Aldosteronism Subtyped With Adrenal Vein Sampling

We sought to measure the clinical benefits of adrenal venous sampling (AVS), a test recommended by guidelines for primary aldosteronism (PA) patients seeking surgical cure, in a large registry of PA patients submitted to AVS. Data of 1625 consecutive patients submitted to AVS in 19 tertiary referral centers located in Asia, Australia, Europe, and North America were collected in a large multicenter international registry. The primary end points were the rate of bilateral success, ascertained lateralization of PA, adrenalectomy, and of cured arterial hypertension among AVS-guided and non AVS-guided adrenalectomy patients. AVS was successful in 80.1% of all cases but allowed identification of unilateral PA in only 45.5% by the criteria in use at each center. Adrenalectomy was performed in 41.8% of all patients and cured arterial hypertension in 19.6% of the patients, 2-fold more frequently in women than men (P<0.001). When AVS-guided, surgery provided a higher rate of cure of hypertension than when non-AVS-guided (40.0% versus 30.5%; P=0.027). Compared with surgical cases, patients treated medically needed more antihypertensive medications (P<0.001) and exhibited a higher rate of persistent hypokalemia requiring potassium supplementation (4.9% versus 2.3%; P<0.01). The low rate of adrenalectomy and cure of hypertension in PA patients seeking surgical cure indicates suboptimal AVS use, possibly related to issues in patient selection, technical success, and AVS data interpretation. Given the better outcomes of AVS-guided adrenalectomy, these results call for actions to improve the diagnostic use of this test that is necessary for detection of surgical PA candidates. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT01234220.

Adrenal Venous Sampling in Primary Aldosteronism: The Usefulness of Contralateral Suppression Index

Adrenal venous sampling (AVS) is the gold standard test to differentiate the unilateral from the bilateral form in patients with primary aldosteronism (PA) although it may be a difficult procedure, especially the successful cannulation of the right adrenal vein. In this report, we describe a 49-year-old female patient diagnosed with PA, after investigating resistant hypertension and refractory hypokalemia. Abdominal computed tomography scan revealed a 2.5 cm adenoma on the right adrenal vein. AVS was performed under cosyntropin infusion. Aldosterone and cortisol concentrations were obtained from the right and left adrenal veins and inferior vena cava (IVC). Cortisol on each adrenal vein divided by cortisol on IVC confirmed successful cannulation of the left side only, which makes it impossible to calculate the lateralization index (LI). From the data on the left adrenal vein and IVC, the aldosterone-to-cortisol ratio divided by the IVC aldosterone-to-cortisol ratio was less than 1.0, suggesting that the left adrenal vein was suppressed with the excess aldosterone originating from the contralateral side (contralateral suppression index (CSI)). Right adrenalectomy was performed; postoperative hypoaldosteronism was confirmed. This report highlights the importance of CSI obtained in AVS when technical difficulties occur making it impossible to obtain LI, which is most commonly used to decide between surgical and clinical management of PA.

Diagnostic value of adrenal iodine-131 6-beta-iodomethyl-19-norcholesterol scintigraphy for primary aldosteronism: a retrospective study at a medical center in North Taiwan

BACKGROUND

Primary aldosteronism (PA) is a common cause of secondary hypertension. Among the many leading causes of PA, the two most frequent are, bilateral adrenal hyperplasia (BAH) and aldosterone-producing adenomas (APA). Since a solitary APA may be cured surgically, but BAH needs lifelong pharmacologic therapy, confirmation is mandatory before surgery. We herein sought to determine the diagnostic value of iodine-131 6-beta-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy to distinguish BAH from APA.

PATIENTS AND METHODS

Patients clinically suspected of PA from March 2000 to October 2016 were retrospectively analyzed. A total of 145 patients, including 74 postunilateral adrenalectomy and seven postradiofrequency ablation for adrenal mass, were reviewed. All patients received NP-59 adrenal scintigraphy prior to surgery. The accuracy of the NP-59 adrenal scintigraphy was confirmed by the pathologic findings and postoperative outcomes.

RESULTS

Among 81 patients receiving interventional procedures for adrenal mass, adenoma was eventually diagnosed in 72 patients according to their pathologic results, with 60 unilaterally and seven bilaterally localized lesions by NP-59 scintigraphy; nevertheless, there were five negative findings initially. The sensitivity, specificity, and positive predictive value of NP-59 scintigraphy for APA detection were therefore 83.3, 44.4, and 92.3%, respectively. Moreover, single-photon emission computed tomography/computed tomography scan increased the sensitivity and specificity, but not the positive predictive value (85.0, 60.0, and 89.5%) of NP-59 scintigraphy in this study.

CONCLUSION

NP-59 adrenal scintigraphy is a useful imaging test to detect APA. Lateralization by this modality prior to surgical intervention may reduce the need for such invasive procedures as adrenal venous sampling.

THE POTENTIAL CLINICAL APPLICATION OF A LOWER BILATERAL ADRENAL LIMB WIDTH RATIO (L/RW) IN PATIENTS WITH BILATERAL PRIMARY HYPERALDOSTERONISM

Objective: This study investigated the characteristics of the adrenal limbs of primary aldosteronism (PA) patients and evaluated the value of the adrenal limb width measurement for the differentiation of unilateral PA from bilateral PA. Methods: A total of 122 PA patients (93 unilateral PA, ages ranged from 23 to 72 years; 29 bilateral PA, ages ranged from 30 to 68 years) who had undergone successful adrenal venous sampling (AVS) and adrenal gland computed tomography (CT) scan were retrospectively included. The maximum width of each adrenal gland limb (normal area on CT images) was measured, the left adrenal limb width to right adrenal limb width ratio (L/Rw) was calculated, and its potential value in the differentiation of unilateral PA and bilateral PA was analyzed. Results: The mean widths of the left adrenal limbs and the right adrenal limbs were 0.52 ± 0.10 cm and 0.43 ± 0.09 cm in unilateral PA patients, versus 0.52 ± 0.10 cm and 0.49 ± 0.12 cm in bilateral PA patients. The L/Rw ratio was 1.22 ± 0.24 in unilateral PA patients and 1.11 ± 0.23 in bilateral PA patients (P<.05). In the subgroup of PA patients over 55 years of age, compared with AVS, the sensitivity and specificity of the L/Rw ratio at 1.06 for subtype classification were 75% and 82%, respectively. Conclusion: A lower L/Rw ratio, referring to the ratio of the left adrenal limb width to the right adrenal limb width, may be a predictor of bilateral PA, especially in PA patients over 55 years of age. Abbreviations: APA = aldosterone-producing adenoma; AVS = adrenal venous sampling; BAH = bilateral adrenal hyperplasia; BMI = body mass index; CT = computed tomography; L/Rw = ratio of left adrenal limb width to right adrenal limb width; PA = primary aldosteronism.

Influence of Adrenal Venous Sampling on Management in Patients with Primary Aldosteronism Independent of Lateralization on Cross-Sectional Imaging

BACKGROUND

Patients with primary aldosteronism undergo imaging of the adrenal glands after confirmation of the disease. Adrenal venous sampling (AVS) is a useful adjunct to imaging, and advocates believe that AVS should be performed before surgical management. Others argue that patients with unilateral lesions on imaging do not require AVS. Although AVS accuracy has been established, few studies have evaluated how AVS alters management. Our study aimed to determine how AVS affected management of these patients.

STUDY DESIGN

Patient data were collected retrospectively from the electronic medical records at a single institution. Patients aged 18 years or older who underwent AVS with successful adrenal vein cannulation from 2007 to 2016 were included. The laterality of AVS was compared with laterality of preprocedural imaging for each patient. The management plan before AVS was determined by laterality on preprocedural imaging. The primary outcomes were management of primary aldosteronism, change in management compared with the plan before AVS, and antihypertensive medication use after therapy.

RESULTS

Seventy-four patients had successful adrenal venous cannulation. Thirty-three (44.6%) patients had AVS lateralization that was concordant with preprocedural imaging. Forty-one (55.4%) patients had AVS lateralization that was non-concordant with preprocedural imaging. There was a change in management in 29 (39.2%) patients.

CONCLUSIONS

Adrenal venous sampling can delineate the source of aldosterone hypersecretion, and often this is not concordant with cross-sectional imaging. We found that many patients avoided a potentially non-curative operation due to AVS. Adrenal venous sampling frequently alters the management of aldosteronomas and should be highly considered in patients before surgical intervention.

Effect of a notch at the distal end of a microcatheter on vein deformation in segmental adrenal venous sampling: a preliminary study using computational fluid dynamics

This study aimed to evaluate the effect of a notch at the distal end of a microcatheter on vein deformation in segmental adrenal venous sampling. A three-dimensional fluid-structure interaction simulation was performed using commercial finite element software. A computational model of a vein with a catheter inserted into it was constructed. The outer and inner diameters of the vein were 0.9 mm and 0.6 mm, respectively, whereas those of the catheter were 0.6 mm and 0.5 mm, respectively. The velocity of the blood flow at the outlet was 85 mm/s. The pressure at the inlet was 0 Pa. The mesh consisted of approximately 660,000 elements. The effect of the number (0-4) and shape (no notch, 1/4 circular, 1/3 circular, semicircular, 2/3 circlecircular, and 3/4 circular) of the notches at the distal end of the microcatheter on the vein deformation when a suction pressure was applied was evaluated. The venous wall displacement was the smallest with the one-notch catheter, followed by the four-notch catheter, and was the smallest with the catheter having 1/4-circular notches, followed by the one with 1/3-circular notches. In conclusion, microcatheters having one notch and 1/4-circular notches reduce vein deformation and lead to successful segmental adrenal venous sampling. Graphical abstract Comparing catheters having different notch shapes.

Success rate of adrenal venous sampling and predictors for success: a retrospective study

Purpose

To report the success rate of adrenal venous sampling (AVS) and identify the predictors for procedural success.

Material and methods

Sixty-four patients (18 men and 46 women) with a mean ± SD age of 50 ± 11.8 years (range 28-69 years) diagnosed as primary hyperaldosteronism, and who underwent AVS from January 2009 to December 2016, were retrospectively reviewed. In our institution, the initial period to perform the AVS was set from 2009 to 2013, and the post-initial period was defined as procedures performed after 2013. Successful sampling was determined when the ratio of cortisol from the adrenal vein to the level of cortisol in the inferior vena cava ≥ 5. The procedural success and subject factors between success and failure were analysed. A p value < 0.05 was considered statistically significant.

Results

The success rate of bilateral AVS was 71.9%. The success rates of right and left AVS were 76.6% and 90.6%, respectively. Male patients were more likely to succeed than female patients (adjusted odds ratio [aOR], 9.83; 95% confidence interval [CI], 1.14-85.14; p = 0.009). In our institution, the procedure performed in the post-initial period also succeeded more often compared to the initial period (aOR, 5.05; 95% CI, 1.2-21.16; p = 0.017). No other factors were associated with the success rate in this study.

Conclusions

The success rate of bilateral AVS in our institution was rather high. Male gender and procedure performed in the post-initial period were significant predictive factors for a successful procedure.

Diagnosis and treatment of primary aldosteronism: practical clinical perspectives

Primary aldosteronism (PA), the most common form of secondary hypertension, can be either surgically cured or treated with targeted pharmacotherapy. PA is frequently undiagnosed and untreated, leading to aldosterone-specific cardiovascular morbidity and nephrotoxicity. Thus, clinicians should perform case detection testing for PA at least once in all patients with hypertension. Confirmatory testing is indicated in most patients with positive case detection testing results. The next step is to determine whether patients with confirmed PA have a disease that can be cured with surgery or whether it should be treated medically; this step is guided by computed tomography scan of the adrenal glands and adrenal venous sampling. With appropriate surgical expertise, laparoscopic unilateral adrenalectomy is safe, efficient and curative in patients with unilateral adrenal disease. In patients who have bilateral aldosterone hypersecretion, the optimal management is a low-sodium diet and lifelong treatment with a mineralocorticoid receptor antagonist administered at a dosage to maintain a high-normal serum potassium concentration without the aid of oral potassium supplements.

Steroid Profiling as an Additional Tool to Confirm One-Sided Hormone Overproduction in Primary Aldosteronism: A Case Report

Primary aldosteronism (PA) is the leading cause of secondary hypertension. The source of aldosterone hypersecretion is often due to a unilateral aldosterone-producing adenoma, and unilateral laparoscopic adrenalectomy is recommended in such patients. Before surgery, confirmation of unilateral hypersecretion is necessary. This is optimally performed by adrenal venous sampling (AVS). However, AVS is not always successful e.g., due to difficulties in the cannulation of the right adrenal vein. Here we present the case of a 53-year-old female patient with primary aldosteronism, a left-sided adrenal mass and an inconspicuous right adrenal. AVS was performed, but cannulation of the right adrenal vein failed. Therefore, aldosterone hypersecretion also of the right adrenal could not be excluded despite higher aldosterone concentrations in the left renal and adrenal vein. To increase the certainty that the left sided adrenal mass was the source of aldosterone hypersecretion, steroid profiling was performed in a sample from the inferior vena cava. This revealed markedly elevated levels of 18-oxocortisol, 18-hydroxycortisol, 11-deoxycorticosterone, and 11-deoxycortisol, a steroid profile that strongly suggested that the left sided adrenal mass was an aldosterone producing adenoma, most likely due to a somatic KCNJ5 mutation. Following unilateral adrenalectomy, CYP11B2 immunohistochemistry, and genetics analysis of the resected adrenal confirmed a solitary aldosterone-producing adenoma with intense aldosterone synthase expression, which harbored a previously described KCNJ5 Phe154Cys mutation. Biochemical and clinical cure was confirmed 6 months postoperatively.

Development of [18F]FAMTO: A novel fluorine-18 labelled positron emission tomography (PET) radiotracer for imaging CYP11B1 and CYP11B2 enzymes in adrenal glands

INTRODUCTION

Primary aldosteronism accounts for 6-15% of hypertension cases, the single biggest contributor to global morbidity and mortality. Whilst ~50% of these patients have unilateral aldosterone-producing adenomas, only a minority of these have curative surgery as the current diagnosis of unilateral disease is poor. Carbon-11 radiolabelled metomidate ([11C]MTO) is a positron emission tomography (PET) radiotracer able to selectively identify CYP11B1/2 expressing adrenocortical lesions of the adrenal gland. However, the use of [11C]MTO is limited to PET centres equipped with on-site cyclotrons due to its short half-life of 20.4 min. Radiolabelling a fluorometomidate derivative with fluorine-18 (radioactive half life 109.8 min) in the para-aromatic position ([18F]FAMTO) has the potential to overcome this disadvantage and allow it to be transported to non-cyclotron-based imaging centres.

METHODS

Two strategies for the one-step radio-synthesis of [18F]FAMTO were developed. [18F]FAMTO was obtained via radiofluorination via use of sulfonium salt (1) and boronic ester (2) precursors. [18F]FAMTO was evaluated in vitro by autoradiography of pig adrenal tissues and in vivo by determining its biodistribution in rodents. Rat plasma and urine were analysed to determine [18F]FAMTO metabolites.

RESULTS

[18F]FAMTO is obtained from sulfonium salt (1) and boronic ester (2) precursors in 7% and 32% non-isolated radiochemical yield (RCY), respectively. Formulated [18F]FAMTO was obtained with >99% radiochemical and enantiomeric purity with a synthesis time of 140 min from the trapping of [18F]fluoride ion on an anion-exchange resin (QMA cartridge). In vitro autoradiography of [18F]FAMTO demonstrated exquisite specific binding in CYP11B-rich pig adrenal glands. In vivo [18F]FAMTO rapidly accumulates in adrenal glands. Liver uptake was about 34% of that in the adrenals and all other organs were <12% of the adrenal uptake at 60 min post-injection. Metabolite analysis showed 13% unchanged [18F]FAMTO in blood at 10 min post-administration and rapid urinary excretion. In vitro assays in human blood showed a free fraction of 37.5%.

CONCLUSIONS

[18F]FAMTO, a new 18F-labelled analogue of metomidate, was successfully synthesised. In vitro and in vivo characterization demonstrated high selectivity towards aldosterone-producing enzymes (CYP11B1 and CYP11B2), supporting the potential of this radiotracer for human investigation.

Adrenal venous sampling: the learning curve of a single interventionalist with 282 consecutive procedures

PURPOSE

Primary aldosteronism (PA) is a common cause of secondary hypertension. Adrenal venous sampling (AVS) is the gold standard for assessing laterality of PA, which is of paramount importance to decide adequate treatment. AVS is a technically complicated procedure with success rates ranging between 30% and 96%. The aim of this study was to investigate the success rate of AVS over time, performed by a single interventionalist.

METHODS

This was a retrospective study based on consecutive AVS procedures performed by a single operator between September 2005 and June 2016. Data on serum concentrations of aldosterone and cortisol from right and left adrenal vein, inferior vena cava, and peripheral vein were collected and selectivity index (SI) calculated. Successful AVS was defined as SI > 5.

RESULTS

In total, 282 AVS procedures were performed on 269 patients, 168 men (62%) and 101 women (38%), with a mean age of 55±11 years (range, 26-78 years). Out of 282 AVS procedures, 259 were successful, giving an overall success rate of 92%. The most common reason for failure was inability to localize the right adrenal vein (n=16; 76%). The success rates were 63%, 82%, and 94% during the first, second, and third years, respectively. During the last 8 years the success rate was 95%, and on average 27 procedures were performed annually.

CONCLUSION

Satisfactory AVS success rate was achieved after approximately 36 procedures and satisfactory success rate was maintained by performing approximately 27 procedures annually. AVS should be limited to few operators that perform sufficiently large number of procedures to achieve, and maintain, satisfactory AVS success rate.

Radiation exposure of adrenal vein sampling: a German Multicenter Study

OBJECTIVE

Adrenal vein sampling (AVS) represents the current diagnostic standard for subtype differentiation in primary aldosteronism (PA). However, AVS has its drawbacks. It is invasive, expensive, requires an experienced interventional radiologist and comes with radiation exposure. However, exact radiation exposure of patients undergoing AVS has never been examined.

DESIGN AND METHODS

We retrospectively analyzed radiation exposure of 656 AVS performed between 1999 and 2017 at four university hospitals. The primary outcomes were dose area product (DAP) and fluoroscopy time (FT). Consecutively the effective dose (ED) was approximately calculated.

RESULTS

Median DAP was found to be 32.5 Gy*cm2 (0.3–3181) and FT 18 min (0.3–184). The calculated ED was 6.4 mSv (0.1–636). Remarkably, values between participating centers highly varied: Median DAP ranged from 16 to 147 Gy*cm2, FT from 16 to 27 min, and ED from 3.2 to 29 mSv. As main reason for this variation, differences regarding AVS protocols between centers could be identified, such as number of sampling locations, frames per second and the use of digital subtraction angiographies.

CONCLUSIONS

This first systematic assessment of radiation exposure in AVS not only shows fairly high values for patients, but also states notable differences among the centers. Thus, we not only recommend taking into account the risk of radiation exposure, when referring patients to undergo AVS, but also to establish improved standard operating procedures to prevent unnecessary radiation exposure.

Saline suppression test parameters may predict bilateral subtypes of primary aldosteronism

BACKGROUND

The saline suppression test (SST) serves to confirm the diagnosis of primary aldosteronism (PA) whilst adrenal vein sampling (AVS) is used to determine whether the aldosterone hypersecretion is unilateral or bilateral. An accurate prediction of bilateral PA based on SST results could reduce the need for AVS.

AIM

We sought to identify SST parameters that reliably predict bilateral PA.

METHODS

The results from 121 patients undergoing SSTs at Monash Health from January 2010 to January 2018 including screening blood tests, imaging, AVS and histopathology results were evaluated. Patients were subtyped into unilateral or bilateral PA based on AVS and surgical outcomes.

RESULTS

Of 113 patients with confirmed PA, 33 had unilateral disease whilst 42 had bilateral disease. In those with bilateral disease, plasma aldosterone concentration (PAC) was significantly lower post-SST, together with a significant fall in the aldosterone-renin ratio (ARR). The combination of PAC < 300 pmol/L and a reduction in ARR post-SST provided 96.8% specificity in predicting bilateral disease. Eighteen of 39 patients (49%) with bilateral PA could have avoided AVS using these criteria.

CONCLUSION

A combination of PAC < 300 pmol/L and a lower ARR post-SST could reliably predict bilateral PA. An independent cohort will be needed to validate these findings.

Factors Associated with Resolution of Hypertension after Adrenalectomy in Patients with Primary Aldosteronism

BACKGROUND

The aim of this study was to investigate the factors associated with resolution of hypertension after adrenalectomy in patients with primary aldosteronism. A secondary aim was to describe our use of the contralateral ratio in adrenal venous sampling (AVS) in the setting of suboptimal successful cannulation rates.

METHODS

A retrospective review of patients who underwent AVS followed by unilateral adrenalectomy for primary aldosteronism was performed.

RESULTS

Complete resolution of hypertension and hypokalemia was seen in 17 of 40 patients (42.5%), while a clinical improvement in hypertension was seen in 38 of 40 (95%). Shorter duration of hypertension, mean aldosteronoma resolution score (ARS), and a high ARS of 3 to 5 were associated with resolution of hypertension after adrenalectomy (P=0.02, P=0.02, and P=0.004, respectively). Of the individual components of ARS, only a duration of hypertension of ≤6 years was associated with resolution of hypertension after adrenalectomy (P=0.03).

CONCLUSION

A shorter duration of hypertension was significantly associated with resolution of hypertension after adrenalectomy in patients with primary aldosteronism.

C-Arm Computed Tomography-Assisted Adrenal Venous Sampling Improved Right Adrenal Vein Cannulation and Sampling Quality in Primary Aldosteronism

BACKGROUND

Adrenal venous sampling (AVS) is a gold standard for subtype classification of primary aldosteronism (PA). However, this procedure has a high failure rate because of the anatomical difficulties in accessing the right adrenal vein. We investigated whether C-arm computed tomography-assisted AVS (C-AVS) could improve the success rate of adrenal sampling.

METHODS

A total of 156 patients, diagnosed with PA who underwent AVS from May 2004 through April 2017, were included. Based on the medical records, we retrospectively compared the overall, left, and right catheterization success rates of adrenal veins during the periods without C-AVS (2004 to 2010, n=32) and with C-AVS (2011 to 2016, n=124). The primary outcome was adequate bilateral sampling defined as a selectivity index (SI) >5.

RESULTS

With C-AVS, the rates of adequate bilateral AVS increased from 40.6% to 88.7% (P<0.001), with substantial decreases in failure rates (43.7% to 0.8%, P<0.001). There were significant increases in adequate sampling rates from right (43.7% to 91.9%, P<0.001) and left adrenal veins (53.1% to 95.9%, P<0.001) as well as decreases in catheterization failure from right adrenal vein (9.3% to 0.0%, P<0.001). Net improvement of SI on right side remained significant after adjustment for left side (adjusted SI, 1.1 to 9.0; P=0.038). C-AVS was an independent predictor of adequate bilateral sampling in the multivariate model (odds ratio, 9.01; P<0.001).

CONCLUSION

C-AVS improved the overall success rate of AVS, possibly as a result of better catheterization of right adrenal vein.

Niche point-of-care endocrine testing - Reviews of intraoperative parathyroid hormone and cortisol monitoring

Point-of-care (POC) testing, which provides quick test results in near-patient settings with easy-to-use devices, has grown continually in recent decades. Among near-patient and on-site tests, rapid intraoperative and intra-procedural assays are used to quickly deliver critical information and thereby improve patient outcomes. Rapid intraoperative parathyroid hormone (ioPTH) monitoring measures postoperative reduction of parathyroid hormone (PTH) to predict surgical outcome in patients with primary hyperparathyroidism, and therefore contributes to the change of parathyroidectomy to a minimally invasive procedure. In this review, recent progress in applying ioPTH monitoring to patients with secondary and tertiary hyperparathyroidism and other testing areas is discussed. In-suite cortisol monitoring facilitates the use of adrenal vein sampling (AVS) for the differential diagnosis of primary aldosteronism and adrenocorticotropic hormone (ACTH)-independent Cushing syndrome. In clinical and psychological research settings, POC testing is also useful for rapidly assessing cortisol in plasma and saliva samples as a biomarker of stress. Careful resource utilization and coordination among stakeholders help to determine the best approach for implementing cost-effective POC testing. Technical advances in integrating appropriate biosensors with microfluidics-based devices hold promise for future real-time POC cortisol monitoring.

Targeting CXCR4 (CXC Chemokine Receptor Type 4) for Molecular Imaging of Aldosterone-Producing Adenoma

Primary aldosteronism is the most frequent cause of secondary hypertension and is associated with increased morbidity and mortality compared with hypertensive controls. The central diagnostic challenge is the differentiation between bilateral and unilateral disease, which determines treatment options. Bilateral adrenal venous sampling, currently recommended for differential diagnosis, is an invasive procedure with several drawbacks, making it desirable to develop novel noninvasive diagnostic tools. When investigating the expression pattern of chemokine receptors by quantitative real-time polymerase chain reaction and immunohistochemistry, we observed high expression of CXCR4 (CXC chemokine receptor type 4) in aldosterone-producing tissue in normal adrenals, adjacent adrenal cortex from adrenocortical adenomas, and in aldosterone-producing adenomas (APA), correlating strongly with the expression of CYP11B2 (aldosterone synthase). In contrast, CXCR4 was not detected in the majority of nonfunctioning adenomas that are frequently found coincidently. The specific CXCR4 ligand 68Ga-pentixafor has recently been established as radiotracer for molecular imaging of CXCR4 expression and showed strong and specific binding to cryosections of APAs in our study. We further investigated 9 patients with primary aldosteronism because of APA by 68Ga-pentixafor-positron emission tomography. The tracer uptake was significantly higher on the side of increased adrenocortical aldosterone secretion in patients with APAs compared with patients investigated by 68Ga-pentixafor-positron emission tomography for other causes. Molecular imaging of aldosterone-producing tissue by a CXCR4-specific ligand may, therefore, be a highly promising tool for noninvasive characterization of patients with APAs.

Subtype prediction of primary aldosteronism by combining aldosterone concentrations in the left adrenal vein and inferior vena cava: a multicenter collaborative study on adrenal venous sampling

Subtype diagnosis of primary aldosteronism (PA) by adrenal vein sampling (AVS) is recommended as a mandatory step for indicating adrenal surgery. It is a technically demanding procedure, especially in the right adrenal vein. The aim of the study was to predict the subtype diagnosis in the absence of values from the right AVS. From the databases of nine centers (WAVES-J), 308 patients with PA who underwent successful AVS were studied. Based on the ipsilateral ratio (IR) (aldosterone/cortisol ratio of the left adrenal vein [A/C_{left AV}] / aldosterone/cortisol ratio of the inferior vena cava [A/C_IVC]), the patients were divided into two groups: the patients with IR ≥ 1.0 (n = 262) and those with IR < 1.0 (n = 46). In patients with IR > 1.0, the A/C_{left AV} was significantly higher in patients with the left unilateral subtype than in patients with the bilateral subtype. Receiver operating characteristic (ROC) curve analysis revealed that an A/C_{left AV} cutoff >68 showed 70.8% sensitivity and 93.5% specificity for the left unilateral subtype. On the other hand, in patients with IR < 1.0, the A/C_{left AV} was significantly lower in patients with the right unilateral subtype. ROC analysis revealed that an A/C_{left AV} cutoff <9 showed 86.7% sensitivity and 75.0% specificity for the right unilateral subtype. Hence, the combination of the IR and A/C ratio in the left adrenal vein is useful for predicting the subtype. The present results provide important information for patients with PA in whom AVS was unsuccessful in the right adrenal vein.

Adrenal venous sampling for primary aldosteronism: laboratory medicine best practice

Primary aldosteronism (PA) is the most common form of secondary hypertension and is critical to identify because when caused by an aldosterone-producing adenoma (APA) or another unilateral form, it is potentially curable, and even when caused by bilateral disease, antihypertensives more specific to PA treatment can be employed (ie, aldosterone antagonists). Identification of unilateral forms is not generally accomplished with imaging because APAs may be small and elude detection, and coincidental identification of a non-functioning incidentaloma contralateral to an APA may lead to removal of an incorrect gland. For this reason, the method of choice for identifying unilateral forms of PA is selective adrenal venous sampling (AVS) followed by aldosterone and cortisol analysis on collected samples. This procedure is technically difficult from a radiological standpoint and, from the laboratory perspective, is fraught with opportunities for preanalytical, analytical and postanalytical error. We review the process of AVS collection, analysis and reporting. Suggestions are made for patient preparation, specimen labelling practices and nomenclature, analytical dilution protocols, which numerical results to report, and the necessary subsequent calculations. We also identify and explain frequent sources of confusion in the aldosterone and cortisol results and provide an example of tabular reporting to facilitate interpretation and communication between laboratorian, radiologist and clinician.

Management of primary aldosteronism in patients with adrenal hemorrhage following adrenal vein sampling: A brief review with illustrative cases

The authors describe the clinical investigation of two cases of primary aldosteronism with adrenal hemorrhage (AH) following adrenal vein sampling. A literature review was conducted regarding the medical management of primary aldosteronism in patients with AH following adrenal vein sampling. Guidelines on the management of primary aldosteronism with AH following adrenal vein sampling are lacking. The two patients were followed with serial imaging to document resolution of AH and treated medically with excellent blood pressure response. Resolution of AH was achieved, but a repeat adrenal vein sampling was deferred given the increased morbidity risk associated with a repeat procedure.

11-Deoxycortisol may be superior to cortisol in confirming a successful adrenal vein catheterization without cosyntropin: a pilot study

AIM

We aimed to compare the performance of nine adrenal steroids in confirming the correct catheter position during adrenal venous sampling (AVS) without cosyntropin in patients with primary hyperaldosteronism.

MATERIALS & METHODS

A successful adrenal vein catheterization without cosyntropin was defined as the ratio of steroids from adrenal to peripheral veins being >3:1. AVS samples from four patients with primary hyperaldosteronism were analyzed.

RESULTS

Compared with the mean ratio of cortisol without cosyntropin, the ratios of 11-deoxycortisol (p = 0.008), dehydroepiandrosterone (p = 0.01) and androstenedione (p = 0.008) were significantly higher. None of the ratios (n = 8) of cortisol from adrenal to peripheral veins exceeded 3:1, while all ratios of 11-deoxycortisol (p < 0.001) were >3.

CONCLUSION

Cosyntropin infusion during AVS may not be necessary if 11-deoxycortisol is used to confirm catheter position.

Subtype Diagnosis of Primary Aldosteronism: Is Adrenal Vein Sampling Always Necessary?

Aldosterone producing adenoma and bilateral adrenal hyperplasia are the two most common subtypes of primary aldosteronism (PA) that require targeted and distinct therapeutic approaches: unilateral adrenalectomy or lifelong medical therapy with mineralocorticoid receptor antagonists. According to the 2016 Endocrine Society Guideline, adrenal venous sampling (AVS) is the gold standard test to distinguish between unilateral and bilateral aldosterone overproduction and therefore, to safely refer patients with PA to surgery. Despite significant advances in the optimization of the AVS procedure and the interpretation of hormonal data, a standardized protocol across centers is still lacking. Alternative methods are sought to either localize an aldosterone producing adenoma or to predict the presence of unilateral disease and thereby substantially reduce the number of patients with PA who proceed to AVS. In this review, we summarize the recent advances in subtyping PA for the diagnosis of unilateral and bilateral disease. We focus on the developments in the AVS procedure, the interpretation criteria, and comparisons of the performance of AVS with the alternative methods that are currently available.