Aldosterone suppression on contralateral adrenal during adrenal vein sampling does not predict blood pressure response after adrenalectomy

Multifocal, Asymmetric Bilateral Primary Aldosteronism Cannot be Excluded by Strong Adrenal Vein Sampling Lateralization: An International Retrospective Cohort Study

BACKGROUND

Primary aldosteronism (PA) has been broadly dichotomized into unilateral and bilateral forms. Adrenal vein sampling (AVS) lateralization indices (LI) ≥2 to 4 are the standard-of-care to recommend unilateral adrenalectomy for presumed unilateral PA. We aimed to assess the rates and characteristics of residual PA after AVS-guided adrenalectomy.

METHODS

We conducted an international, retrospective, cohort study of patients with PA from 7 referral centers who underwent unilateral adrenalectomy based on LI≥4 on baseline and/or cosyntropin-stimulated AVS. Aldosterone synthase (CYP11B2) immunohistochemistry and next generation sequencing were performed on available formalin-fixed paraffin-embedded adrenal tissue.

RESULTS

The cohort included 283 patients who underwent AVS-guided adrenalectomy, followed for a median of 326 days postoperatively. Lack of PA cure was observed in 16% of consecutive patients, and in 22 patients with lateralized PA on both baseline and cosyntropin-stimulated AVS. Among patients with residual PA postoperatively, 73% had multiple CYP11B2 positive areas within the resected adrenal tissue (versus 23% in those cured), wherein CACNA1D mutations were most prevalent (63% versus 33% in those cured). In adjusted regression models, independent predictors of postoperative residual PA included Black versus White race (odds ratio, 5.10 [95% CI, 1.45-17.86]), AVS lateralization only at baseline (odds ratio, 8.93 [95% CI 3.00-26.32] versus both at baseline and after cosyntropin stimulation), and CT-AVS disagreement (odds ratio, 2.75 [95% CI, 1.20-6.31]).

CONCLUSIONS

Multifocal, asymmetrical bilateral PA is relatively common, and it cannot be excluded by robust AVS lateralization. Long-term postoperative monitoring should be routinely pursued, to identify residual PA and afford timely initiation of targeted medical therapy.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01234220.

Role of Adrenal Vein Sampling in Guiding Surgical Decision in Primary Aldosteronism

Adrenal vein sampling (AVS) is recommended for subtyping primary aldosteronism (PA) to identify lateralized or bilateral sources of aldosterone excess, allowing for better decision-making in regard to medical or surgical management on a case-by-case basis. To date, no consensus exists on protocols to be used during AVS, especially concerning sampling techniques, the timing of sampling, and whether or not to use adrenocorticotropic hormone (ACTH) stimulation. Interpretation criteria for selectivity, lateralization, and contralateral suppression vary from one expert center to another, with some favoring strict cut-offs to others being more permissive. Clinical and biochemical post-operative outcomes can also be influenced by AVS criteria utilized to indicate surgical therapy.In this review, we reanalyze studies on AVS highlighting the recent pathological findings of frequent micronodular hyperplasia adjacent to a dominant aldosteronoma (APA) overlapping with bilateral idiopathic hyperaldosteronism (IHA) etiologies, as opposed to the less frequent unilateral single aldosteronoma. The variable expression of melanocortin type 2 receptors in the nodules and hyperplasia may explain the frequent discordance in lateralization ratios between unstimulated and ACTH- stimulated samples. We conclude that aldosterone values collected during simultaneous bilateral sampling, both at baseline and post-ACTH stimulation, are required to adequately evaluate selectivity, lateralization, and contralateral suppression during AVS, to better identify all patients with PA that can benefit from a surgical indication. Recommended cut-offs for each ratio are also presented.

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.

Primary aldosteronism - a multidimensional syndrome

Primary aldosteronism is a common cause of hypertension and is a risk factor for cardiovascular and renal morbidity and mortality, via mechanisms mediated by both hypertension and direct insults to target organs. Despite its high prevalence and associated complications, primary aldosteronism remains largely under-recognized, with less than 2% of people in at-risk populations ever tested. Fundamental progress made over the past decade has transformed our understanding of the pathogenesis of primary aldosteronism and of its clinical phenotypes. The dichotomous paradigm of primary aldosteronism diagnosis and subtyping is being redefined into a multidimensional spectrum of disease, which spans subclinical stages to florid primary aldosteronism, and from single-focal or multifocal to diffuse aldosterone-producing areas, which can affect one or both adrenal glands. This Review discusses how redefining the primary aldosteronism syndrome as a multidimensional spectrum will affect the approach to the diagnosis and subtyping of primary aldosteronism.

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.

High Prevalence of Autonomous Aldosterone Production in Hypertension: How to Identify and Treat It

PURPOSE OF REVIEW

Primary aldosteronism (PA) affects millions of individuals worldwide. When unrecognized, PA leads to cardiovascular and renal complications via mechanisms independent from those mediated by hypertension. In this review, we emphasize the importance of PA screening in at-risk populations, and we provide options for customized PA therapy, with consideration for a variety of clinical care settings.

RECENT FINDINGS

Compelling evidence puts PA at the forefront of secondary hypertension etiologies. Cardiovascular and renal damage likely begins in early stages of renin-independent aldosterone excess. PA must be considered not only in patients with resistant hypertension or hypokalemia, but also when hypertension is associated with obstructive sleep apnea or atrial fibrillation, or in those with early-onset hypertension. Screening with plasma aldosterone and renin is widely accessible, and targeted PA therapy can successfully circumvent the excess cardiorenal risk relative to equivalent primary hypertension. Identifying and treating PA in early stages provide opportunities for personalized hypertension therapy in a large number of patients. Additionally, early targeted therapy of PA is essential for pivoting the care of such patients from reactive to preventive of cardiovascular and renal morbidity and mortality.

Diagnosis and treatment of primary aldosteronism

Primary aldosteronism is a common cause of secondary hypertension associated with excess cardiovascular morbidities. Primary aldosteronism is underdiagnosed because it does not have a specific, easily identifiable feature and clinicians can be poorly aware of the disease. The diagnostic investigation is a multistep process of screening, confirmatory testing, and subtype differentiation of unilateral from bilateral forms for therapeutic management. Adrenal venous sampling is key for reliable subtype identification, but can be bypassed in patients with specific characteristics. For unilateral disease, surgery offers the possibility of cure, with total laparoscopic unilateral adrenalectomy being the treatment of choice. Bilateral forms are treated mainly with mineralocorticoid receptor antagonists. The goals of treatment are to normalise both blood pressure and excessive aldosterone production, and the primary aims are to reduce associated comorbidities, improve quality of life, and reduce mortality. Prompt diagnosis of primary aldosteronism and the use of targeted treatment strategies mitigate aldosterone-specific target organ damage and with appropriate patient management outcomes can be excellent. Advances in molecular histopathology challenge the traditional concept of primary aldosteronism as a binary disease, caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Somatic mutations drive autonomous aldosterone production in most adenomas. Many of these same mutations have been identified in nodular lesions adjacent to an aldosterone-producing adenoma and in patients with bilateral disease. In addition, germline mutations cause rare familial forms of aldosteronism (familial hyperaldosteronism types 1-4). Genetic testing for inherited forms in suspected cases of familial hyperaldosteronism avoids the burdensome diagnostic investigation in positive patients. In this Review, we discuss advances and future management approaches in the diagnosis of primary aldosteronism.

Contralateral Suppression Index Does Not Predict Clinical Cure in Patients Undergoing Surgery for Primary Aldosteronism

BACKGROUND

Adrenal venous sampling (AVS) is recommended before adrenalectomy for patients with primary aldosteronism (PA) over 35 years old. The literature examining contralateral suppression (CoS) on AVS in predicting surgical outcomes is conflicting. We examined the presence of CoS in patients who underwent adrenalectomy while adjusting for clinical and biochemical factors associated with a clinical cure of hypertension (ccHTN).

METHODS

We performed a retrospective review of patients with successful AVS who underwent unilateral adrenalectomy for PA at a quaternary referral center. Patients were excluded if they had overt cortisol co-secretion, or inadequate follow-up. We first evaluated the aldosterone resolution score (ARS) in predicting ccHTN in our cohort. Next, the receiver-operator characteristic analysis (ROC) was used to determine the optimal contralateral suppression index (CSI) cutoff to define CoS. We performed univariable and multivariable analyses of factors associated with ccHTN. The primary outcome was ccHTN defined as blood pressure less than 140/90 mmHg, and off blood pressure medications.

RESULTS

Of the 102 patients on bivariable analysis, age, sex, duration of HTN, number of medications, preoperative systolic blood pressure, and creatinine level were associated with ccHTN. ROC analysis of ARS had an AUC of 0.850 (p < 0.001). On multivariable analysis, only ARS remained associated with ccHTN (OR 3.40, 95% CI 1.20-9.61, p = 0.021). CSI was not significantly associated with ccHTN on ROC, bivariable, or multivariable analyses.

CONCLUSION

The presence of CoS was not useful in predicting ccHTN following unilateral adrenalectomy for PA in our cohort. After adjusting for clinical and biochemical factors, ARS remains a useful predictor for ccHTN.

Contralateral Suppression at Adrenal Venous Sampling Is Associated with Renal Impairment Following Adrenalectomy for Unilateral Primary Aldosteronism

BACKGROUND

Adrenal venous sampling (AVS) is performed to distinguish the subtype of primary aldosteronism (PA). The clinical implication of contralateral suppression (CS; aldosterone/cortisolnondominant<aldosterone/cortisolperipheral) at AVS remains unclear. We aimed to investigate the clinical significance of CS and its impact on postoperative outcomes after unilateral adrenalectomy.

METHODS

In this retrospective observational multi-center study, we analyzed PA patients who underwent both successful adrenocorticotropin hormone-stimulated AVS and unilateral adrenalectomy. Successful cannulation was defined as the selectivity index (cortisoladrenal/cortisolperipheral) ≥3. Clinical and biochemical outcomes after unilateral adrenalectomy were evaluated based on the international Primary Aldosteronism Surgical Outcome consensus.

RESULTS

Among 263 patients analyzed, 247 had CS (93.9%). Patients with CS had lower serum potassium levels, higher plasma aldosterone concentration, higher aldosterone-to-renin ratio (ARR), and larger adenoma size than those without CS. Those with CS showed significantly higher lateralization index than those without CS (P<0.001). Although postoperative blood pressure and ARR significantly decreased in those with CS, clinical and biochemical outcomes were comparable in both groups. When the cut-off value of age was determined using receiver operating characteristic (ROC) analysis, patients aged ≥50 years old with contralateral suppression index (CSI; the ratio between aldosterone/cortisolnondominant and aldosterone/cortisolperipheral) ≤0.26 had greater odds ratio (6.43; 95% confidence interval, 1.30 to 31.69) of incident chronic kidney disease than those aged <50 years with CSI >0.26 after adjusting for other factors.

CONCLUSION

CS may not predict postoperative clinical and biochemical outcomes in subjects with unilateral aldosterone excess, but it is associated with postsurgical deterioration of renal function in subjects over 50 years with CSI ≤0.26.

Steroidogenic Activity in Unresected Adrenals Associated With Surgical Outcomes in Primary Aldosteronism

[Figure: see text].

Primary aldosteronism subtyping in the setting of partially successful adrenal vein sampling

BACKGROUND AND AIMS

Frequent failure of adrenal vein (AV) cannulation is a major obstacle to the universal use of adrenal vein sampling (AVS) for subtyping primary aldosteronism (PA). This study aimed to confirm and modify the value of a previously reported AVS parameter for PA subtyping in the case of cannulation failure on one side.

METHODS

Successfully catheterized AVS studies in 157 patients (121 patients as a derivation cohort and 36 patients as a validation cohort) from two tertiary hospitals were retrospectively reviewed. The AV/inferior vena cava (IVC) index was defined by dividing the aldosterone/cortisol ratio (ACR) of AV by the ACR of the IVC. Cutoff values for lateralized PA were obtained from two methods: scatterplots and the values corresponding to Youden's index in receiver operating characteristic (ROC) curves, on the assumption of catheterization failure on one side.

RESULTS

Due to multiple samplings in a single AVS procedure, 252 left AV/IVC ratios (LIRs) and 272 right AV/IVC ratios (RIRs) were calculated. Scatterplot cutoffs of LIR >5.4 or <0.5 predicted unilateral PA with a sensitivity of 42.1% and a specificity of 98.6%. Scatterplot cutoffs of RIR <0.5 or >7.0 showed a sensitivity of 55.1% and a specificity of 98.6%. ROC curve cutoffs of LIR ⩽0.8 or >3.1 predicted unilateral PA with a sensitivity of 82.5% and a specificity of 69.6%. ROC curve cutoffs of RIR ⩽0.8 or >3.9 resulted in 87.4% sensitivity and 80.7% specificity.

CONCLUSION

In the case of unilateral AVS failure, the AV/IVC index may help in diagnosing PA subtype.

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.

Utility of adrenocorticotropic hormone in adrenal vein sampling despite the occurrence of discordant lateralization

BACKGROUND

Adrenal vein sampling (AVS) is crucial for accurate lateralization of aldosterone excess but it is technically challenging due to the difficulty of adrenal vein cannulation. The use of adrenocorticotropic hormone (ACTH) to improve cannulation success is controversial and can lead to discordant lateralization outcomes.

OBJECTIVE

To evaluate the utility of ACTH in two centres with different levels of AVS expertise and formulate a strategy for interpreting discordant results.

DESIGN

A retrospective cross-sectional analysis of AVS results and postoperative patient outcomes.

SETTING

Two large tertiary hospitals with harmonized AVS protocols where adrenal venous samples are collected both before and after ACTH stimulation.

MEASUREMENTS

Cannulation success (measured by selectivity index, SI), lateralization (measured by lateralization index, LI) and postoperative biochemical cure.

RESULTS

Number of AVS procedures judged to have successful bilateral adrenal vein cannulation increased from 53% pre- to 73% post-ACTH. The increase in cannulation success was significantly higher in centre where AVS was performed by multiple radiologists with a lower basal success rate. In both centres, the proportion of cases deemed to display lateralization significantly decreased with the use of ACTH (70% pre- to 52% post-ACTH). Based on postoperative outcomes of patients with discordant results who underwent unilateral adrenalectomy, the combination of LI >3 pre-ACTH and LI >2 post-ACTH was predictive of a biochemical cure.

CONCLUSION

Adrenocorticotropic hormone can increase the rate of cannulation success during AVS at the expense of reduced lateralization. The criteria for lateralization should be carefully determined based on local data when ACTH is used.

Subtype diagnosis, treatment, complications and outcomes of primary aldosteronism and future direction of research: a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension

: Primary aldosteronism is a frequent cause of secondary hypertension requiring a specific pharmacological treatment with mineralocorticoid receptor antagonist or with unilateral adrenalectomy. These treatments have shown to reduce the excess of cardiovascular risk characteristically associated with this disease. In part I of this consensus, we discussed the procedures for the diagnosis of primary aldosteronism. In the present part II, we address the strategies for the differential diagnosis of primary aldosteronism subtypes and therapy. We also discuss the evaluation of outcomes and provide suggestions for follow-up as well as cardiovascular and metabolic complications specifically associated with primary aldosteronism. Finally, we analyse the principal gaps of knowledge and future challenges for research in this field.

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

BACKGROUND

We investigated whether the contralateral suppression index in aldosterone-producing adrenal adenoma could be used as a diagnostic criterion when catheterization in either right or left adrenal vein fails or when a discrepancy in the adrenal vein sampling (AVS) results and imaging findings occurs in the real-world practice.

METHODS

We retrospectively reviewed 48 patients who had resistant hypertension (HTN) or hypokalemia with a biochemical diagnosis of primary aldosteronism and who underwent AVS from January 2009 to June 2017 at a tertiary referral hospital. Selection index (SI), lateralization index (LI), and contralateral suppression index (CSI) were calculated based on AVS results and the final clinical outcomes were evaluated.

RESULTS

The catheterization of both adrenal veins was successful in 43 of 48 (89.6%) patients. The lateralization based only on LI was performed in 23 out of 43 (53.5%) patients. When CSI and LI were combined in decision making, the concordance between adrenal computed tomography scan and AVS for unilateral lesion improved from 59.3% (19/32) to 75.0% (24/32). CSI also correlated well with unilateral adrenal disease in the catheterization failure group. The final outcomes of HTN were better in the contralateral suppression group.

CONCLUSION

CSI combined with LI could be a supplementary diagnostic tool in patients with non-lateralization or catheterization failure and predict the clinical outcomes of HTN in patients with primary aldosteronism.

Controversies and advances in adrenal venous sampling in the diagnostic workup of primary aldosteronism

Adrenal venous sampling (AVS) is a key part of the diagnostic workup of primary aldosteronism, distinguishing unilateral from bilateral disease and determining treatment options. Although AVS is a well-established procedure, many aspects remain controversial, including optimal patient selection for the procedure and exactly how AVS is performed and interpreted. Despite the controversies, a growing body of evidence supports the use of AVS in most patients with primary aldosteronism, though some specific patient groups may be able to forego AVS and proceed directly to treatment. Although AVS remains a difficult procedure, success rates may be improved with the use of advanced CT imaging techniques and/or rapid cortisol assays. New advances in nuclear imaging and steroid profiling may also offer alternatives or adjuncts to AVS in the future.

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.

Primary aldosteronism subtype discordance between computed tomography and adrenal venous sampling

The primary aldosteronism (PA) subtype is usually confirmed by CT and adrenal venous sampling (AVS). However, the subtype diagnosis by AVS is not necessarily consistent with the subtype diagnosis by CT. Patients with PA who show bilateral lesions (normal-appearing adrenals or bilateral adrenal nodules) on CT but unilateral disease on AVS are often found. The aim of this study was to evaluate whether patients with PA subtype discordance between CT and AVS obtain benefits from unilateral adrenalectomy. We retrospectively analyzed 362 consecutive patients with PA who underwent both CT and adrenocorticotropic hormone-unstimulated AVS at Kanazawa University Hospital. Surgical outcomes for unilateral PA were evaluated according to the criteria of the Primary Aldosteronism Surgical Outcome study. In our study, the success rate of AVS in patients with bilateral lesions on CT was 89% (191/214). Furthermore, the discordance rate between CT and AVS in patients with bilateral lesions on CT was 39% (74/191). After surgery, patients with bilateral lesions on CT but unilateral disease on AVS (n = 17) had a lower complete biochemical success rate than those with unilateral lesions on CT and ipsilateral disease on AVS (n = 30) (41% vs. 80%, p = 0.01), but clinical and biochemical benefits (the complete and partial success combined) were not significantly different between them (76% vs. 93% (p = 0.11) and 70% vs. 90% (p = 0.10), respectively). In conclusion, patients with bilateral lesions on CT but unilateral disease on AVS benefited from surgery, and AVS should be performed for patients who pursue surgical management when the CT findings suggest bilateral lesions.

Surgical outcomes of laparoscopic adrenalectomy for primary hyperaldosteronism: 20 years of experience in a single institution

Purpose

Recently, posterior retroperitoneoscopic adrenalectomy (PRA) has been reported to have some advantages over laparoscopic transperitoneal adrenalectomy (LTA). The objectives of this study were to report our experience over 12 years with laparoscopic adrenalectomy for primary hyperaldosteronism (PHA) and to examine surgical outcomes of PRA compared with LTA in patients with PHA.

Methods

The medical records of 527 patients who underwent minimally invasive adrenalectomy, including LTA or PRA, from January 2006 until May 2017 were reviewed at Severance Hospital (Seoul, Korea). Clinicopathologic characteristics and surgical outcomes of 146 patients with PHA who underwent LTA (19 patients) or PRA (127 patients) were analyzed retrospectively by complete chart review.

Results

The overall rates of biochemical and clinical cure were 91.1% and 93.1%, respectively. The mean operation time of the PRA group was significantly shorter than that of the LTA group (72.3 ± 24.1 minutes vs. 115.7 ± 69.7 minutes, P = 0.015). The length of hospital stay in the PRA group was significantly shorter than in the LTA group (3.5 ± 1.3 days vs. 4.2 ± 1.6 days, P = 0.029), and the first meal after surgery came earlier in the PRA group (0.3 ± 0.5 days vs. 0.6 ± 0.5 days, P = 0.049). The number of pain-killers used was also significantly smaller in the PRA group (2.3 ± 2.1 vs. 4.3 ± 2.3, P < 0.001).

Conclusion

PRA offers an alternative or likely superior method for treatment of small adrenal diseases such as PHA, with improved surgical outcomes.

11 C-Metomidate PET/CT is a useful adjunct for lateralization of primary aldosteronism in routine clinical practice

OBJECTIVE

To describe clinical practice experience of ¹¹ C-Metomidate PET/CT as an adjunct to adrenal vein sampling (AVS) in the lateralization of aldosterone-producing adenomas (APA) in primary aldosteronism (PA).

CONTEXT

Accurate lateralization of APA in the setting of PA offers the potential for surgical cure and improved long-term cardiovascular outcomes. Challenges associated with AVS, the current gold standard lateralization modality, mean that only a small proportion of potentially eligible patients currently make it through to surgery. This has prompted consideration of alternative strategies for lateralization, including the application of novel molecular PET tracers such as ¹¹ C-Metomidate.

DESIGN

Clinical Service Evaluation/Retrospective audit.

PATIENTS

Fifteen individuals with a confirmed diagnosis of PA, undergoing lateralization with ¹¹ C-Metomidate PET/CT prior to final clinical decision on surgical vs medical management.

MEASUREMENTS

All patients underwent screening aldosterone renin ratio (ARR), followed by confirmatory testing with the seated saline infusion test, according to Endocrine Society Clinical Practice Guidelines. Adrenal glands were imaged using dedicated adrenal CT. ¹¹ C-Metomidate PET/CT was undertaken due to equivocal or failed AVS. Management outcomes were assessed by longitudinal measurement of blood pressure, ARR, number of hypertensive medications following adrenalectomy or institution of medical therapy.

RESULTS

We describe the individual lateralization and clinical outcomes for 15 patients with PA.

CONCLUSION

¹¹ C-Metomidate PET/CT in conjunction with adrenal CT and AVS provided useful information which aided clinical decision-making for PA within a multidisciplinary hypertension clinic.

Adrenal venous sampling with or without adrenocorticotropic hormone stimulation: A meta-analysis

CONTEXT

Adrenal venous sampling (AVS) with or without adrenocorticotropic hormone (ACTH) stimulation is the test of choice to identify patients with a surgically curable subtype of primary aldosteronism (PA). Whether AVS with ACTH stimulation is more effective than AVS without ACTH stimulation remains controversial.

OBJECTIVE

To compare the effectiveness of AVS with ACTH stimulation and AVS without ACTH stimulation in patients with PA.

METHODS

The Cochrane Library, PubMed, Embase, and Web of Science databases were searched to identify relevant articles. All cohort studies comparing the 2 techniques (AVS with ACTH stimulation and AVS without ACTH stimulation in patient with PA) were included in the analysis.

RESULTS

A total of 14 studies met the inclusion criteria, and they were analyzed. AVS with ACTH stimulation did not significantly reduce the number of incorrect lateralization more than AVS without ACTH stimulation in patients with PA [OR: 0.76, 95% confidence interval (CI): 0.36, 1.59; P=0.47]. AVS with ACTH stimulation significantly reduced the number of unsuccessful cannulations of both adrenal veins more than AVS without ACTH stimulation in patients with PA (OR: 0.26, 95% CI: 0.17, 0.40; P<0.00001). For subgroup analyses, it also significantly reduced the number of unsuccessful cannulations of left adrenal vein and right adrenal vein (OR: 0.14, 95% CI: 0.06, 0.33; P<0.00001 and OR: 0.30, 95% CI: 0.12, 0.71; P=0.007, respectively).

CONCLUSION

AVS with ACTH stimulation can significantly reduce the number of unsuccessful cannulations, without significantly reducing the number of incorrect lateralization. Further studies are still needed to verify these findings.

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.

Contralateral suppression of aldosterone at adrenal venous sampling predicts hyperkalemia following adrenalectomy for primary aldosteronism

BACKGROUND

We aimed to determine whether a greater degree of contralateral suppression of aldosterone secretion at adrenal venous sampling predicted the development of postoperative hyperkalemia after unilateral adrenalectomy for primary aldosteronism.

METHODS

A retrospective analysis of patients undergoing unilateral adrenalectomy for primary aldosteronism between 2004-2015 was performed. Clinical and biochemical parameters of patients who developed hyperkalemia (≥5.2 mmol/L) after unilateral adreanlectomy were compared with those who remained normokalemic. The contralateral suppression index was defined as the aldosterone-to-cortisol ratio from the nondominant adrenal vein divided by the aldosterone-to-cortisol ratio from the external iliac vein.

RESULTS

Of 192 patients who met criteria for inclusion, 12 (6.3%) developed hyperkalemia (median serum potassium 5.5 mmol/L, range 5.2-6.2 mmol/L), with a median time to onset of 13.5 days (range 7-55 days). Five patients had transiently increased serum potassium concentrations that normalized spontaneously. Four patients received mineralocorticoid replacement therapy with fludrocortisone. On univariate analysis, hyperkalemic patients had slightly greater preoperative serum creatinine levels (1.2 vs 1.0 mg/dL, P = .01), higher postoperative creatinine (1.3 vs 1.0 mg/dL, P = .02), lesser median contralateral suppression index (0.14 vs 0.27, P = .03), and larger adenomas (1.9 vs 1.4 cm, P = .02). On multivariable logistic regression, the contralateral suppression index remained the only significant predictor of postoperative hyperkalemia (P = .04) with an optimal cut-off of <0.47.

CONCLUSION

Hyperkalemia after unilateral adrenalectomy for primary aldosteronism is uncommon and usually transient, but may require mineralocorticoid supplementation. Patients with a contralateral suppression index of <0.47 require meticulous follow-up and monitoring of serum potassium concentrations after unilateral adrenalectomy.

Body mass index and contralateral ratio predict outcome following unilateral adrenalectomy in primary aldosteronism

The effect of unilateral adrenalectomy on blood pressure (BP) outcome in primary aldosteronism (PA) is diverse. Therefore, we sought to investigate the preoperative factors contributing to postoperative BP outcome. Data for 96 PA patients who underwent unilateral adrenalectomy at our institution from January 2000 to February 2015 were retrospectively collected. Based on postoperative BP after a 12-month follow-up period, the patients were categorized into two groups: cured (C) (<140/90 mm Hg with no antihypertensive drug) and not cured (NC) (if not normotensive). Patient demographics, blood and urine data, data of loading tests and adrenal vein sampling were evaluated. In all, 46 patients were categorized as C and 50 patients as NC. There were significantly more males in the NC group. Age, body mass index (BMI), number of antihypertensive drugs prescribed, serum uric acid concentration and contralateral ratio (CR) after adrenocorticotropic hormone stimulation were significantly higher in the NC group. In the multivariate model, BMI and CR significantly correlated with resolution outcome. The optimal cutoff values were 23.3 kg m^-2 for BMI and 0.5 for CR, and when both parameters were used as predictors, the most optimal cutoff values for BMI and CR were 25.2 kg m^-2 and 0.1, respectively. BMI and CR significantly correlated with BP outcome after adrenalectomy. To our knowledge, this is the first report to show that in addition to BMI, CR is a factor in postoperative BP outcome and to determine the optimal cutoff values of BMI and CR and calculate their sensitivities and specificities.

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.

Prevalence and Clinical Manifestations of Primary Aldosteronism Encountered in Primary Care Practice

BACKGROUND

Despite being widely recognized as the most common form of secondary hypertension, among the general hypertensive population the true prevalence of primary aldosteronism (PA) and its main subtypes, aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH), remains a matter of debate.

OBJECTIVES

This study sought to determine the prevalence and clinical phenotype of PA in a large cohort of unselected patients with hypertension, consecutively referred to our hypertension unit, by 19 general practitioners from Torino, Italy.

METHODS

Following withdrawal from all interfering medications, patients were screened for PA using the ratio of serum aldosterone to plasma renin activity. PA was diagnosed according to Endocrine Society guidelines. The diagnosis was confirmed or excluded by an intravenous saline infusion test or captopril challenge test and subtype differentiation was performed by adrenal computed tomography scanning and adrenal vein sampling, using strict criteria to define successful cannulation and lateralization of aldosterone production.

RESULTS

A total of 1,672 primary care patients with hypertension (569 newly diagnosed and 1,103 patients already diagnosed with arterial hypertension) were included in the study. A total of 99 patients (5.9%) were diagnosed with PA and conclusive subtype differentiation by adrenal vein sampling was made in 91 patients (27 patients with an APA and 64 patients with BAH). The overall prevalence of PA increased with the severity of hypertension, from 3.9% in stage 1 hypertension to 11.8% in stage 3 hypertension. Patients with PA more frequently displayed target organ damage and cardiovascular events compared with those without PA, independent of confounding variables.

CONCLUSIONS

Our results demonstrated that PA is a frequent cause of secondary hypertension, even in the general population of patients with hypertension, and indicates that most of these patients should be screened for PA.

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.

Primary Aldosteronism as a Risk Factor for Vertebral Fracture

CONTEXT

Some observational studies have revealed an association between excessive aldosterone levels and reduced bone mineral density (BMD). However, whether patients with primary aldosteronism (PA) are at higher risk of fracture than healthy individuals remains unclear.

OBJECTIVE

This study aimed to clarify whether PA represents a risk factor for vertebral fracture (VF).

DESIGN AND PATIENTS

We enrolled 56 patients with PA and 56 age- and sex-matched healthy individuals. Serum and urinary biological parameters, BMD, and presence of VFs were evaluated in both groups. We compared parameters between PA and control participants and performed multiple logistic regression analyses after adjustments for variables.

RESULTS

Patients with PA showed higher systolic and diastolic blood pressure, higher hemoglobin A1c (HbA1c) and triglycerides, higher urinary calcium-to-creatinine ratio, and lower high-density lipoprotein cholesterol than controls (P < 0.05, each). Prevalence of VFs was significantly higher in patients with PA (44.6%) than in controls (23.2%, P < 0.05). Patients with PA showed severe fracture more frequently than controls. Multivariate logistic regression analyses adjusted for age, sex, and body mass index identified PA as being associated with the presence of VFs (odds ratio, 3.13; 95% confidence interval, 1.30 to 7.51; P < 0.05). This association remained statistically significant after further adjustment for systolic and diastolic blood pressure, HbA1c, triglycerides, and high-density lipoprotein cholesterol but not after adjustment for calcium-to-creatinine ratio and BMD.

CONCLUSIONS

We identified PA as a risk factor for VF, independent of blood pressure, HbA1c, and lipid profile. Fracture severity was significantly higher in patients with PA than in age- and sex-matched controls.

A Case of Adrenal Vein Sampling in Primary Aldosteronism With Homolateral Suppression

Context:

Adrenal venous sampling (AVS) is regarded as the gold standard for diagnosis of primary aldosteronism (PA) subtypes, although some authors have questioned its diagnostic accuracy and highlighted the lack of standardized procedure protocols and interpretation criteria for AVS. In particular, the usefulness of cosyntropin stimulation and benefit of superselective adrenal vein catheterization have been hotly debated.

Objective:

We report a case that highlights the potential pitfalls of superselective sampling and demonstrates a negligible effect of cosyntropin stimulation on aldosterone secretion in nonadenomatous adrenal tissue when an aldosterone-producing adenoma (APA) is present.

Intervention and Results:

A 38-year-old man with PA and a single right macroadenoma underwent AVS at our center. The procedure was performed both under basal conditions and during cosyntropin stimulation. Right adrenal vein angiography demonstrated two branches of the main adrenal vein trunk, one draining the nodule and one draining the right adrenal gland. Hormonal assays confirmed adrenal origin of left-sided and all right-sided samples, and were consistent with lateralization on the right side, with suppression of aldosterone secretion in the left adrenal gland and in the nonadenomatous right adrenal tissue. Cosyntropin-stimulated AVS results were similar to those of the unstimulated procedure.

Conclusions:

Cosyntropin stimulation does not significantly affect aldosterone secretion from nonadenomatous adrenal tissue when an APA is present and can therefore be used during AVS for PA. Superselective AVS should be performed with caution and interpreted by expert clinicians.

New Advances in the Diagnostic Workup of Primary Aldosteronism

Primary aldosteronism is an important and common cause of hypertension that carries a high burden of morbidity. Outcomes, however, are excellent if diagnosed and treated appropriately. The diagnostic workup for primary aldosteronism is complex and comprises three steps: (1) screening, (2) confirmatory testing, and (3) subtype differentiation. In this review, we discuss recent advances in the diagnostic workup for primary aldosteronism. The development of accurate mass spectroscopy-based assays for measuring aldosterone will lead to improved confidence in all diagnostic aspects involving measurement of aldosterone, and accurate measurement of angiotensin II may soon advance us beyond the measurement of renin. We now have a greater understanding of hormonal influences on the aldosterone/renin ratio, which are particularly important when screening premenopausal women or those taking estrogen-containing preparations. Confirmatory testing is important, but there are limitations to the commonly used methods that have recently become more apparent, with new approaches offering a way forward. Adrenal venous sampling (AVS) is a challenging procedure but is important for deciding on treatment options. Success rates may be improved by the use of Synacthen stimulation and of rapid intraprocedural measurement of cortisol. Better understanding of AVS interpretation criteria allows improved prognostication and aids treatment decisions. The use of labeled metomidate positron emission tomography computed tomography scanning may also offer an alternative to AVS in some units. Although the diagnostic approach to patients with primary aldosteronism remains a complex multistep process in which attention to detail is important, recent advances will improve patient care and outcomes.

Does ACTH improve the diagnostic performance of adrenal vein sampling for subtyping primary aldosteronism?

OBJECTIVE

Adrenal vein sampling (AVS) is used for determining treatment options for primary aldosteronism (PA), but is a difficult procedure. Adrenocorticotropic hormone (ACTH) infusion or bolus has been reported to improve AVS success rates by increasing cortisol secretion, but effects on lateralization are controversial. We therefore assessed the effects of ACTH in regard to AVS success and lateralization in our unit, after a change in protocol to ACTH-stimulated AVS.

SETTING

AVS was performed after overnight recumbency in patients with PA confirmed by fludrocortisone suppression testing. Bilateral sequential sampling was performed before and after an intravenous bolus of 250 mcg of ACTH. Lateralization was defined as an aldosterone/cortisol ratio in one adrenal vein at least twice peripheral, combined with a contralateral adrenal ratio no higher than peripheral (contralateral suppression).

RESULTS

In 47 AVS procedures, the median adrenal/peripheral cortisol gradient increased on the left (11·6 vs 18·2 μg/100 ml, P < 0·001) and right (15·6 vs 31·5 μg/100 ml, P < 0·001) after ACTH. A total of 34 of 47 studies were diagnostic pre-ACTH (six failing because of low aldosterone levels bilaterally and seven failing to cannulate one or both sides) vs 44 of 47 (P = 0·011) studies diagnostic post-ACTH (failure to cannulate one or both sides in 3). Concordance between diagnostic studies pre- and post-ACTH was 91%, but two bilateral cases became unilateral after ACTH and one unilateral case before ACTH was bilateral afterwards.

CONCLUSIONS

ACTH improved cortisol gradients and aldosterone secretion, resulting in a reduction in the proportion of nondiagnostic studies. There was a low proportion of discordance between pre- and post-ACTH diagnoses, the significance of which is unclear.

Primary Aldosteronism: Changing Definitions and New Concepts of Physiology and Pathophysiology Both Inside and Outside the Kidney

In the 60 years that have passed since the discovery of the mineralocorticoid hormone aldosterone, much has been learned about its synthesis (both adrenal and extra-adrenal), regulation (by renin-angiotensin II, potassium, adrenocorticotrophin, and other factors), and effects (on both epithelial and nonepithelial tissues). Once thought to be rare, primary aldosteronism (PA, in which aldosterone secretion by the adrenal is excessive and autonomous of its principal regulator, angiotensin II) is now known to be the most common specifically treatable and potentially curable form of hypertension, with most patients lacking the clinical feature of hypokalemia, the presence of which was previously considered to be necessary to warrant further efforts towards confirming a diagnosis of PA. This, and the appreciation that aldosterone excess leads to adverse cardiovascular, renal, central nervous, and psychological effects, that are at least partly independent of its effects on blood pressure, have had a profound influence on raising clinical and research interest in PA. Such research on patients with PA has, in turn, furthered knowledge regarding aldosterone synthesis, regulation, and effects. This review summarizes current progress in our understanding of the physiology of aldosterone, and towards defining the causes (including genetic bases), epidemiology, outcomes, and clinical approaches to diagnostic workup (including screening, diagnostic confirmation, and subtype differentiation) and treatment of PA.

Hyperaldosteronism: How to Discriminate Among Different Disease Forms?

Primary aldosteronism (PA), characterized by the inappropriate and abnormal adrenal secretion of aldosterone, is the most common cause of secondary hypertension. PA has been shown to increase cardiovasular and cerebrovascular risks in comparison with essential hypertension. PA is a multi-faceted disease, which comprises unilateral forms, benefitting from surgical treatment, and bilateral forms, which are the best managed medically. PA is more frequently sporadic, but in some cases, it displays a familial transmission pattern. For these reasons, it is important to diagnose PA early on and correctly distinguish and manage its different forms. In this review, we analyze the different forms of PA, with attention on the diagnostic pathway and the genetics of the disease.

Basal and Post-ACTH Aldosterone and Its Ratios Are Useful During Adrenal Vein Sampling in Primary Aldosteronism

CONTEXT

Adrenal vein sampling (AVS) is required to identify a lateralized or bilateral aldosterone source in primary aldosteronism.

OBJECTIVES

Our objectives were to compare basal and post-ACTH selectivity ratio (SR) and lateralization ratio (LR) and to determine the prevalence of basal contralateral suppression and its effect on surgical outcome.

PATIENTS AND INTERVENTION

Bilateral simultaneous adrenal vein samples were obtained before and after a 250-μg bolus of ACTH. Analyses were conducted on 171 technically successful AVS and on the subgroup of 66 operated patients with evaluable outcome data.

RESULTS

ACTH increased selectivity on both sides from 66.7% in basal samples (SR ≥ 2) to 91.8% poststimulation (SR ≥ 5). A discordance of lateralization between basal (LR ≥ 2) and post-ACTH (LR ≥ 4) values was observed in 28% of cases, which were mostly lateralized cases basally that became bilateral post-ACTH. Basal CL suppression is present in only 30% using absolute ratio of aldosterone between the opposite (nondominant) adrenal vein and the peripheral vein AOPP/AP below 1.5 vs in 77% using aldosterone/cortisol ratio (A/C)OPP/(A/C)P below 1.5. The absence of CL suppression was associated with a lower rate of response to adrenalectomy in terms of clinical and biochemical parameters with difference in clinical cure (55% vs 13% P = .0003) and overall cure (35% vs 9%, P = .0084) using AOPP/AP, but not when using (A/C)OPP/(A/C)P.

CONCLUSIONS

Stimulation with ACTH is useful to improve selectivity of AVS but can frequently modify interpretation of lateralization. Basal ratios are as important as post-ACTH ratios to set an indication of adrenalectomy. AOPP/AP is superior to (A/C)OPP/(A/C)P to assess contralateral suppression. Infrequent CL suppression reveals frequent occurrence of contralateral hyperplasia in lateralized cases and helps predict postoperative outcomes.

A NEW CLINICAL PREDICTION CRITERION ACCURATELY DETERMINES A SUBSET OF PATIENTS WITH BILATERAL PRIMARY ALDOSTERONISM BEFORE ADRENAL VENOUS SAMPLING

OBJECTIVE

Adrenal venous sampling (AVS) is the only available method to distinguish bilateral from unilateral primary aldosteronism (PA). AVS has several drawbacks, so it is reasonable to avoid this procedure when the results would not affect clinical management. Our objective was to identify a clinical criterion that can reliably predict nonlateralized AVS as a surrogate for bilateral PA that is not treated surgically.

METHODS

A retrospective diagnostic cross-sectional study conducted at Slovenian national endocrine referral center included 69 consecutive patients (mean age 56 ± 8 years, 21 females) with PA who underwent AVS. PA was confirmed with the saline infusion test (SIT). AVS was performed sequentially during continuous adrenocorticotrophic hormone (ACTH) infusion. The main outcome measures were variables associated with nonlateralized AVS to derive a clinical prediction rule.

RESULTS

Sixty-seven (97%) patients had a successful AVS and were included in the statistical analysis. A total of 39 (58%) patients had nonlateralized AVS. The combined criterion of serum potassium ≥3.5 mmol/L, post-SIT aldosterone <18 ng/dL, and either no or bilateral tumor found on computed tomography (CT) imaging had perfect estimated specificity (and thus 100% positive predictive value) for bilateral PA, saving an estimated 16% of the patients (11/67) from unnecessary AVS. The best overall classification accuracy (50/67 = 75%) was achieved using the post-SIT aldosterone level <18 ng/dL alone, which yielded 74% sensitivity and 75% specificity for predicting nonlateralized AVS.

CONCLUSIONS

Our clinical prediction criterion appears to accurately determine a subset of patients with bilateral PA who could avoid unnecessary AVS and immediately commence with medical treatment.

Subtype Diagnosis of Primary Aldosteronism: Approach to Different Clinical Scenarios

Identification and management of patients with primary aldosteronism are of utmost importance because it is a frequent cause of endocrine hypertension, and affected patients display an increase of cardio- and cerebro-vascular events, compared to essential hypertensives. Distinction of primary aldosteronism subtypes is of particular relevance to allocate the patients to the appropriate treatment, represented by mineralocorticoid receptor antagonists for bilateral forms and unilateral adrenalectomy for patients with unilateral aldosterone secretion. Subtype differentiation of confirmed hyperaldosteronism comprises adrenal CT scanning and adrenal venous sampling. In this review, we will discuss different clinical scenarios where execution, interpretation of adrenal vein sampling and subsequent patient management might be challenging, providing the clinician with useful information to help the interpretation of controversial procedures.

Clinical Management and Outcomes of Adrenal Hemorrhage Following Adrenal Vein Sampling in Primary Aldosteronism

Aldosterone-producing adenoma and bilateral adrenal hyperplasia account for >90% of all primary aldosteronism cases. Distinguishing between bilateral and unilateral disease is of fundamental importance because it allows targeted therapy. Adrenal vein sampling (AVS) is the only reliable means to preoperatively differentiate between unilateral and bilateral subtypes. A rare but serious complication of AVS is an adrenal hemorrhage (AH). We retrospectively examined in detail 24 cases of AH during AVS in 6 different referral hypertension centers. AH more often affected the right adrenal (n=18) than the left (n=5, P<0.001); 1 bilateral. Median duration of experience of the radiologist in AVS at the time of AH was 5.0 years (0.6-7.8) and AH occurred with both highly experienced (>10 years) and less experienced radiologists. Of 9 patients who suffered AH in the gland contralateral to an aldosterone-producing adenoma and who underwent complete (n=6) or partial (n=3) unilateral adrenalectomy, only one required long-term corticosteroid replacement for adrenal insufficiency. No reduction in blood pressure or biochemical resolution of primary aldosteronism occurred in any of those patients who experienced AH in the gland ipsilateral to an aldosterone-producing adenoma (n=6) or who had bilateral adrenal hyperplasia (n=9). No patient required invasive treatments to control bleeding or blood transfusion. In conclusion, AH usually has a positive outcome causing either no or minor effects on adrenal function, and AVS should remain the best approach to primary aldosteronism subtype differentiation.

Importance of contralateral aldosterone suppression during adrenal vein sampling in the subtype evaluation of primary aldosteronism

OBJECTIVES

Adrenal vein sampling (AVS) is the standard criterion for the subtype diagnosis in primary aldosteronism (PA). Although lateralized index (LI) ≥4 after cosyntropin stimulation is the commonly recommended cut-off for unilateral aldosterone hypersecretion, many of the referral centres in the world use LI cut-off of <4 without sufficient evidence for its diagnostic accuracy.

AIM

The aim of the study was to establish the diagnostic significance of contralateral (CL) aldosterone suppression for the subtype diagnosis in patients with LI <4 in AVS.

DESIGN AND PATIENTS

A retrospective multicentre study was conducted in Japan. Of 124 PA patients subjected to unilateral adrenalectomy after successful AVS with cosyntropin administration, 29 patients with LI < 4 were included in the study. The patients were divided into Group A with CL suppression (n = 16) and Group B (n = 13) without CL suppression. Three outcome indices were assessed after 6 months postoperatively: normalization/significant improvement of hypertension, normalization of the aldosterone to renin ratio (ARR) and normalization of hypokalaemia.

RESULTS

The normalization/significant improvement of hypertension was 81% in Group A and 54% in Group B (P = 0·2). The normalization of ARR was 100% in Group A and 46% in Group B (P = 0·004). Hypokalaemia was normalized in all patients of both groups. The overall cure rate of PA based on meeting all the three criteria was 81% in Group A and 31% in Group B (P = 0·01).

CONCLUSIONS

In patients with PA, where the LI is <4 on AVS, CL suppression of aldosterone is an accurate predictor of a unilateral source of aldosterone excess. CL suppression data should be interpreted in conjunction with computed tomographic adrenal imaging findings to guide surgical management.

Is there a role for segmental adrenal venous sampling and adrenal sparing surgery in patients with primary aldosteronism?

OBJECTIVE AND DESIGN

Adrenal venous sampling (AVS) is critical to determine the subtype of primary aldosteronism (PA). Central AVS (C-AVS)--that is, the collection of effluents from bilateral adrenal central veins (CV)--sometimes does not allow differentiation between bilateral aldosterone-producing adenomas (APA) and idiopathic hyperaldosteronism. To establish the best treatment course, we have developed segmental AVS (S-AVS); that is, we collect effluents from the tributaries of CV to determine the intra-adrenal sources of aldosterone overproduction. We then evaluated the clinical utility of this novel approach in the diagnosis and treatment of PA.

METHODS

We performed C-AVS and/or S-AVS in 297 PA patients and assessed the accuracy of diagnosis based on the results of C-AVS (n=138, 46.5%) and S-AVS (n=159, 53.5%) by comparison with those of clinicopathological evaluation of resected specimens.

RESULTS

S-AVS demonstrated both elevated and attenuated secretion of aldosterone from APA and non-tumorous segments, respectively, in patients with bilateral APA and recurrent APA. These findings were completely confirmed by detailed histopathological examination after surgery. S-AVS, but not C-AVS, also served to identify APA located distal from the CV.

CONCLUSIONS

Compared to C-AVS, S-AVS served to identify APA in some patients, and its use should expand the pool of patients eligible for adrenal sparing surgery through the identification of unaffected segments, despite the fact that S-AVS requires more expertise and time. Especially, this new technique could enormously benefit patients with bilateral or recurrent APA because of the preservation of non-tumorous glandular tissue.

Immunohistochemical, genetic and clinical characterization of sporadic aldosterone-producing adenomas

Adrenal glands removed for unilateral primary aldosteronism (PA) display marked histological heterogeneity. Recently reported somatic mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D can partially account for these differences. In this study we aimed at combining phenotypic and genotypic characteristics, integrating genetic and immunohistochemistry correlates in sporadic PA. Seventy-one adrenal glands have been included in the study and analyzed for mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D. Histological examination and immunohistochemical staining for CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase) were performed on aldosterone-producing adenomas (APAs) and adjacent adrenal cortex. In our cohort, the final histopathological diagnosis was multinodular hyperplasia in 22.5% of the patients and single nodule in 77.5%. Forty-five percent of the removed adrenals displayed extra-APA CYP11B2-positive cell nests (B2-CN). Among adrenal vein sampling parameters the suppression of contralateral adrenal was more frequent and the lateralization index was higher in the subgroup of patients without extra-APA B2-CN compared to the subgroup with extra-APA B2-CN. KCNJ5-mutated APAs were composed mainly of zona fasciculata-like cells with high expression of CYP11B1, while ATP1A1, ATP2B3 and CACNA1D-mutated APAs presented more frequently a zona-glomerulosa-like phenotype with high expression of CYP11B2. We observed a significant inverse correlation between CYP11B2 expression and the size of the nodules and, if CYP11B2 expression was corrected for tumor volume, a significant correlation with plasma aldosterone and aldosterone to renin ratio. Our findings indicate that combination of genotyping and immunohistochemistry improves the final histopathological diagnosis between single nodule and multinodular hyperplasia of the assessed adrenals.

Defining contralateral adrenal suppression in primary aldosteronism: implications for diagnosis and outcome

OBJECTIVE

Unilateral primary aldosteronism (PA) should have a contralaterally normal and therefore suppressed adrenal zona glomerulosa. However, there is no validated definition of adrenal suppression. We created two biochemical hypotheses of adrenal suppression based upon measurements taken during adrenal vein sampling (AVS) to determine whether either proved useful for interpretation of AVS or prediction of hypertension outcome in operated cases.

DESIGN

Retrospective database analysis.

PATIENTS

Ninety-nine cases of PA from a tertiary hypertension unit.

MEASUREMENTS

Hypothesis 1 was the proportional suppression of the uninvolved/lowest adrenal(aldo/cortisol) to IVC(aldo/cortisol) ratio pre- and post cosyntropin. Hypothesis 2 was the absolute decrease in the uninvolved adrenal(aldo/cortisol) ratio after cortrosyn injection. ROC analysis performed using lateralization and hypertension resolution as the outcomes of interest.

RESULTS

Hypothesis 1 proved highly predictive of lateralization with a ROC AUC of 0.958, P < 0.0001, giving adrenal(aldo/cortisol):IVC(aldo/cortisol) <1.4 as the optimized criterion (sensitivity 90%, specificity 94%). For blood pressure outcomes in the surgical subgroup (n = 52), hypertension resolution was most commonly seen among subjects with adrenal suppression by both definitions although there was significant overlap with subjects requiring ongoing medication.

CONCLUSIONS

Post cosyntropin suppression of the uninvolved adrenal-to-IVC ratio is a highly useful definition of adrenal suppression that accurately predicts unilateral PA. This may be particularly useful in a case where AVS fails to catheterize one of the adrenal veins but suppression is seen on the other side. Adrenal suppression may also predict blood pressure outcome, however, a much larger PA database is likely necessary to determine the relative contribution of this predictor.

Issues in the Diagnosis and Treatment of Primary Aldosteronism

Primary aldosteronism (PA) is associated with a high rate of cardio- and cerebrovascular complications and metabolic alterations. PA is also recognized as the most frequent, although often unrecognized, secondary form of hypertension. Guidelines have been released to assist clinicians in the diagnostic work-up and subtype differentiation of PA. In this review we discuss and compare the available guidelines in the context of our professional experience and evaluate diagnostic and therapeutic aspects that are still a matter of debate.