The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline

Inflammation and Fibrosis in Perirenal Adipose Tissue of Patients With Aldosterone-Producing Adenoma

The prevalence of primary aldosteronism is much higher than previously thought. Recent studies have shown that primary aldosteronism is related to a higher risk of cardiovascular events. However, the underlying mechanism is not yet clear. Here we investigate the characteristics, including inflammation, fibrosis, and adipokine expression, of adipose tissues from different deposits in patients with aldosterone-producing adenoma (APA). Inflammation and fibrosis changes were evaluated in perirenal and subcutaneous adipose tissues obtained from patients with APA (n = 16), normotension (NT; n = 10), and essential hypertension (EH; n = 5) undergoing laparoscopic surgery. We also evaluated the effect of aldosterone in isolated human perirenal adipose tissue stromal vascular fraction (SVF) cells and investigated the effect of aldosterone in mouse 3T3-L1 and brown preadipocytes. Compared with the EH group, significantly higher levels of interleukin-6 (IL-6) and tumor necrosis factor-α messenger RNA (mRNA) and protein were observed in perirenal adipose tissue of patients with APA. Expression of genes related to fibrosis and adipogenesis in perirenal adipose tissue was notably higher in patients with APA than in patients with NT and EH. Aldosterone significantly induced IL-6 and fibrosis gene mRNA expression in differentiated SVF cells. Aldosterone treatment enhanced mRNA expression of genes associated with inflammation and fibrosis and stimulated differentiation of 3T3-L1 and brown preadipocytes. In conclusion, these data indicate that high aldosterone in patients with APA may induce perirenal adipose tissue dysfunction and lead to inflammation and fibrosis, which may be involved in the high risk of cardiovascular events observed in patients with primary aldosteronism.

Cardiovascular events and target organ damage in primary aldosteronism compared with essential hypertension: a systematic review and meta-analysis

BACKGROUND

There is conflicting evidence, relying on heterogeneous studies, as to whether aldosterone excess is responsible for an increased risk of cardiovascular and cerebrovascular complications in patients with primary aldosteronism. We aimed to assess the association between primary aldosteronism and adverse cardiac and cerebrovascular events, target organ damage, diabetes, and metabolic syndrome, compared with the association of essential hypertension and these cardiovascular and end organ events, by integrating results of previous studies.

METHODS

We did a meta-analysis of prospective and retrospective observational studies that compared patients with primary aldosteronism and essential hypertension, to analyse the association between primary aldosteronism and stroke, coronary artery disease (as co-primary endpoints), atrial fibrillation and heart failure, target organ damage, metabolic syndrome, and diabetes (as secondary endpoints). We searched MEDLINE and Cochrane Library for articles published up to Feb 28, 2017, with no start date restriction. Eligible studies compared patients with primary aldosteronism with patients with essential hypertension (as a control group) and reported on the clinical events or endpoints of interest. We also compared primary aldosteronism subtypes, aldosterone-producing adenoma, and bilateral adrenal hyperplasia.

FINDINGS

We identified 31 studies including 3838 patients with primary aldosteronism and 9284 patients with essential hypertension. After a median of 8·8 years (IQR 6·2-10·7) from the diagnosis of hypertension, compared with patients with essential hypertension, patients with primary aldosteronism had an increased risk of stroke (odds ratio [OR] 2·58, 95% CI 1·93-3·45), coronary artery disease (1·77, 1·10-2·83), atrial fibrillation (3·52, 2·06-5·99), and heart failure (2·05, 1·11-3·78). These results were consistent for patients with aldosterone-producing adenoma and bilateral adrenal hyperplasia, with no difference between these subgroups. Similarly, primary aldosteronism increased the risk of diabetes (OR 1·33, 95% CI 1·01-1·74), metabolic syndrome (1·53, 1·22-1·91), and left ventricular hypertrophy (2·29, 1·65-3·17).

INTERPRETATION

Diagnosing primary aldosteronism in the early stages of disease, with early initiation of specific treatment, is important because affected patients display an increased cardiovascular risk compared with patients with essential hypertension.

FUNDING

None.

Cardiometabolic outcomes and mortality in medically treated primary aldosteronism: a retrospective cohort study

BACKGROUND

Mineralocorticoid receptor (MR) antagonists are the recommended medical therapy for primary aldosteronism. Whether this recommendation effectively reduces cardiometabolic risk is not well understood. We aimed to investigate the risk of incident cardiovascular events in patients with primary aldosteronism treated with MR antagonists compared with patients with essential hypertension.

METHODS

We did a cohort study using patients from a research registry from Brigham and Women's Hospital, Massachusetts General Hospital, and their affiliated partner hospitals. We identified patients with primary aldosteronism using International Classification of Disease, 9th and 10th Revision codes, who were assessed between the years 1991-2016 and were at least 18 years of age. We excluded patients who underwent surgical adrenalectomy, had a previous cardiovascular event, were not treated with MR antagonists, or had no follow-up visits after study entry. From the same registry, we identified a population with essential hypertension that was frequency matched by decade of age at study entry. We extracted patient cohort data and collated it into a de-identified database. The primary outcome was an incident cardiovascular event, defined as a composite of incident myocardial infarction or coronary revascularisation, hospital admission with congestive heart failure, or stroke, which was assessed using adjusted Cox regression models. Secondary outcomes were the individual components of the composite cardiovascular outcome, as well as incident atrial fibrillation, incident diabetes, and death.

FINDINGS

We identified 602 eligible patients with primary aldosteronism treated with MR antagonists and 41 853 age-matched patients with essential hypertension from the registry. The two groups of patients had comparable cardiovascular risk profiles and blood pressure throughout the study. The incidence of cardiovascular events was higher in patients with primary aldosteronism on MR antagonists than in patients with essential hypertension (56·3 [95% CI 48·8-64·7] vs 26·6 [26·1-27·2] events per 1000 person-years, adjusted hazard ratio 1·91 [95% CI 1·63-2·25]; adjusted 10-year cumulative incidence difference 14·1 [95% CI 10·1-18·0] excess events per 100 people). Patients with primary aldosteronism also had higher adjusted risks for incident mortality (hazard ratio [HR] 1·34 [95% CI 1·06-1·71]), diabetes (1·26 [1·01-1·57]), and atrial fibrillation (1·93 [1·54-2·42]). Compared with essential hypertension, the excess risk for cardiovascular events and mortality was limited to patients with primary aldosteronism whose renin activity remained suppressed (<1 μg/L per h) on MR antagonists (adjusted HR [2·83 [95% CI 2·11-3·80], and 1·79 [1·14-2·80], respectively) whereas patients who were treated with higher MR antagonist doses and had unsuppressed renin (≥1 μg/L per h) had no significant excess risk.

INTERPRETATION

The current practice of MR antagonist therapy in primary aldosteronism is associated with significantly higher risk for incident cardiometabolic events and death, independent of blood pressure control, than for patients with essential hypertension. Titration of MR antagonist therapy to raise renin might mitigate this excess risk.

FUNDING

US National Institutes of Health.

Complete remission of hypertension in a hemodialysis patient after adrenalectomy for primary aldosteronism and renal transplantation

A 64-year-old man was admitted to our hospital for the hormonal evaluation of a right adrenal adenoma. He had been diagnosed with severe proteinuria and hypertension, and antihypertensive treatment was started at the age of 60. His renal function gradually declined, and hemodialysis was begun at the age of 64. Since his blood pressure was uncontrollable and resistant to antihypertensive treatment, an endocrinological examination was performed for an incidental right adrenal mass detected by computed tomography. The results of screening, including captopril challenge and an adrenocorticotropin stimulation test for primary aldosteronism, and adrenal venous sampling suggested excessive aldosterone secretion from the right adrenal gland. Adrenalectomy was performed; his blood pressure decreased and became well-controlled with a reduced antihypertensive regimen. Furthermore, he received renal transplantation which resulted in normalization of his serum potassium level, improvement of renal function and hormonal levels such as plasma renin activity and aldosterone concentration, and satisfactory blood pressure without any antihypertensive medications. This case is extremely important to demonstrate the effects of adrenalectomy for primary aldosteronism in a hemodialysis patient. It is possible that adrenalectomy may be a useful treatment for primary aldosteronism even in patients undergoing hemodialysis. Careful long-term follow-up of our case and investigations of the efficacy of adrenalectomy in similar cases are needed to address this issue.

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.

Double hit! A unique case of resistant hypertension

A middle-aged woman with obesity, hyperlipidaemia and diet-controlled diabetes was referred for resistant hypertension. Her blood pressure (BP) was uncontrolled on five medications, including a diuretic. Physical exam revealed a systolic ejection murmur, and ECHO demonstrated moderate hypertrophy. Laboratory examination revealed elevated aldosterone level (20.7 ng/dL) and elevated aldosterone:renin ratio (41.4 (ng/dL)/(ng/mL/h)), meeting criteria for primary aldosteronism (PA), and confirmed by saline infusion testing. CT scan of the adrenals was non-localising. Adrenal venous sampling confirmed bilateral idiopathic adrenal hyperplasia. Concurrent primary hyperparathyroidism was demonstrated by elevated calcium and parathyroid hormone levels and localised by sestamibi scan. Idiopathic adrenal hyperplasia was treated medically with spironolactone. Her BP remained elevated until postparathyroidectomy. Evidence shows that a hyperfunctioning parathyroid gland may contribute to maintaining hyperaldosteronism in PA making this bidirectional link unique. The significance of this case is in the potential for further understanding of the pathophysiology of common causes of secondary hypertension.

Genetic Causes of Functional Adrenocortical Adenomas

Aldosterone and cortisol, the main mineralocorticoid and glucocorticoid hormones in humans, are produced in the adrenal cortex, which is composed of three concentric zones with specific functional characteristics. Adrenocortical adenomas (ACAs) can lead to the autonomous secretion of aldosterone responsible for primary aldosteronism, the most frequent form of secondary arterial hypertension. In the case of cortisol production, ACAs lead to overt or subclinical Cushing syndrome. Genetic analysis driven by next-generation sequencing technology has enabled the discovery, during the past 7 years, of the genetic causes of a large subset of ACAs. In particular, somatic mutations in genes regulating intracellular ionic homeostasis and membrane potential have been identified in aldosterone-producing adenomas. These mutations all promote increased intracellular calcium concentrations, with activation of calcium signaling, the main trigger for aldosterone production. In cortisol-producing adenomas, recurrent somatic mutations in PRKACA (coding for the cyclic adenosine monophosphate-dependent protein kinase catalytic subunit α) affect cyclic adenosine monophosphate-dependent protein kinase A signaling, leading to activation of cortisol biosynthesis. In addition to these specific pathways, the Wnt/β-catenin pathway appears to play an important role in adrenal tumorigenesis, because β-catenin mutations have been identified in both aldosterone- and cortisol-producing adenomas. This, together with different intermediate states of aldosterone and cortisol cosecretion, raises the possibility that the two conditions share a certain degree of genetic susceptibility. Alternatively, different hits might be responsible for the diseases, with one hit leading to adrenocortical cell proliferation and nodule formation and the second specifying the hormonal secretory pattern.

Discordance between imaging and immunohistochemistry in unilateral primary aldosteronism

OBJECTIVE

Correct subtyping of primary aldosteronism (PA) is essential for good surgical outcomes. Adrenal vein sampling (AVS) and/or computed tomography (CT) are used for PA subclassification. Clinical and/or biochemical improvement after surgery, however, is not always achieved in patients with presumed unilateral PA. We aimed to identify the pitfalls in PA subclassification leading to surgical treatment failures.

PATIENTS AND DESIGN

We retrospectively studied 208 patients who underwent adrenal vein sampling (AVS) for PA subclassification in a tertiary referral centre, between January 2009 and August 2016. Simultaneous bilateral AVS was performed before and after cosyntropin administration. We implemented immunohistochemistry for aldosterone synthase (CYP11B2) and 17α-hydroxylase/17,20 lyase (CYP17A1) in adrenal glands resected from patients without improvement of PA after surgical treatment and from those with limitations in AVS interpretation.

RESULTS

Of 55 patients who underwent adrenalectomy, three (5.5%) had no improvement of PA. All three patients underwent partial adrenalectomy to remove a CT-detected nodule present on the same side with AVS lateralization. Immunohistochemistry revealed a CYP11B2-negative nodule in both cases available. All patients who underwent total adrenalectomy based on AVS lateralization benefitted from surgery, including three patients with unilateral unsuccessful AVS and aldosterone suppression in the catheterized side vs inferior vena cava.

CONCLUSIONS

Radiographically identified adrenal nodules are not always a source of PA, even when ipsilateral with AVS lateralization. These data caution against reliance on imaging findings, either alone or in conjunction with AVS, to guide surgery for PA.

Mouse Models of Primary Aldosteronism: From Physiology to Pathophysiology

Primary aldosteronism (PA) is a common form of endocrine hypertension that is characterized by the excessive production of aldosterone relative to suppressed plasma renin levels. PA is usually caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Somatic mutations have been identified in several genes that encode ion pumps and channels that may explain the aldosterone excess in over half of aldosterone-producing adenomas, whereas the pathophysiology of bilateral adrenal hyperplasia is largely unknown. A number of mouse models of hyperaldosteronism have been described that recreate some features of the human disorder, although none replicate the genetic basis of human PA. Animal models that reproduce the genotype-phenotype associations of human PA are required to establish the functional mechanisms that underlie the endocrine autonomy and deregulated cell growth of the affected adrenal and for preclinical studies of novel therapeutics. Herein, we discuss the differences in adrenal physiology across species and describe the genetically modified mouse models of PA that have been developed to date.

Histopathological and genetic characterization of aldosterone-producing adenomas with concurrent subclinical cortisol hypersecretion: a case series

PURPOSE

Aldosterone-producing adenomas with concurrent subclinical cortisol hypersecretion are reported in an increasing number of patients. Five aldosterone-producing adenomas from patients with primary aldosteronism and subclinical hypercortisolism were examined.

THE AIMS OF OUR STUDY WERE

(1) to analyze pathological features and immunohistochemical expression of CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase) in these tumors; (2) to investigate somatic mutations involved in adrenal steroid hypersecretion and/or tumor growth.

METHODS

Archival micro-dissected paraffin-embedded slides from tumor specimens were used for histological and molecular studies. Immunohistochemistry was performed using monoclonal anti-CYP11B1 and anti-CYP11B2 antibodies. Cellular composition was determined by examining for known features of zona fasciculata and zona glomerulosa, and immunoreactivity for CYP11B1 and CYP11B2 by McCarty H-score. Spot regions for mutations in KCNJ5, ATP1A1, ATP2B3, CACNA1D, PRKACA, and CTNNB1 gene sequences were evaluated.

RESULTS

Four APAs showed a predominant (≥50%) zona fasciculata-like cell pattern: one tumor had CYP11B1 H-score = 150, no detectable CYP11B2 expression, and harbored a PRKACA p.Leu206Arg mutation (that we have reported previously elsewhere), one had no CYP11B1 expression, CYP11B2 H-score = 40, and no mutations; the remaining two adenomas had high CYP11B1 H-score (160 and 240, respectively) and low CYP11B2 H-score (30 and 15, respectively), with the latter harboring a CTNNB1 p.Ser45Phe activating mutation. One of five aldosterone-producing adenomas had a predominant zona glomerulosa-like pattern, CYP11B1 H-score = 15, CYP11B2 H-score = 180, and no mutations.

CONCLUSIONS

The majority of aldosterone-producing adenomas with concurrent subclinical cortisol hypersecretion were composed mainly of zona fasciculata-like cells, while CYP11B1 and CYP11B2 immunostaining demonstrated clear heterogeneity. In a subset of cases, different somatic mutations may be involved in hormone excess and tumor formation.

Generating method-specific Reference Ranges - A harmonious outcome?

OBJECTIVES

When laboratory Reference Ranges (RR) do not reflect analytical methodology, result interpretation can cause misclassification of patients and inappropriate management. This can be mitigated by determining and implementing method-specific RRs, which was the main objective of this study.

DESIGN AND METHODS

Serum was obtained from healthy volunteers (Male + Female, n > 120) attending hospital health-check sessions during June and July 2011. Pseudo-anonymised aliquots were stored (at - 70 °C) prior t° analysis on Abbott ARCHITECT c16000 chemistry and i2000SR immunoassay analysers. Data were stratified by gender where appropriate. Outliers were excluded statistically (Tukey method) to generate non-parametric RRs (2.5th + 97.5th percentiles). RRs were compared to those quoted by Abbott and UK Pathology Harmony (PH) where possible. For 7 selected tests, RRs were verified using a data mining approach.

RESULTS

For chemistry tests (n = 23), Upper or Lower Reference Limits (LRL or URL) were > 20% different from Abbott ranges in 25% of tests (11% from PH ranges) but in 38% for immunoassay tests (n = 13). RRs (mmol/L) for sodium (138-144), potassium (3.8-4.9) and chloride (102-110) were considerably narrower than PH ranges (133-146, 3.5-5.0 and 95-108, respectively). The gender difference for ferritin (M: 29-441, F: 8-193 ng/mL) was more pronounced than reported by Abbott (M: 22-275, F: 5-204 ng/mL). Verification studies showed good agreement for chemistry tests (mean [SD] difference = 0.4% [1.2%]) but less so for immunoassay tests (27% [29%]), particularly for TSH (LRL).

CONCLUSION

Where resource permits, we advocate using method-specific RRs in preference to other sources, particularly where method bias and lack of standardisation limits RR transferability and harmonisation.

Subtyping of primary aldosteronism with adrenal vein sampling: Hormone- and side-specific effects of cosyntropin and metoclopramide

BACKGROUND

Cosyntropin and metoclopramide can affect the subtyping of primary aldosteronism when used with adrenal vein sampling by exerting hormone- and side-specific effects on cortisol and aldosterone secretion. We investigated how these stimuli affect the selectivity index, the relative aldosterone secretion index, and the lateralization index in consecutive primary aldosteronism patients submitted to adrenal vein sampling.

METHODS

We recruited 171 patients; of these, 149 underwent adrenal vein sampling before and after stimulation with cosyntropin (250 µg intravenous bolus, n= 53, 73% with an aldosterone-producing adenoma) or with metoclopramide (10 mg intravenous bolus, n= 96, 65% aldosterone-producing adenoma), and 32 with an aldosterone-producing adenoma were investigated for the relative gene expression of dopamine, melanocortin 2, and 5-hydroxytryptamine (serotonin) 4 receptor with microarrays. Cosyntropin increased the selectivity index similarly on both sides; metoclopramide did not. Cosyntropin decreased relative aldosterone secretion index on the aldosterone-producing adenoma side but not contralaterally. Metoclopramide did not affect the selectivity index, but increased the relative aldosterone secretion index similarly on both sides. Because of these changes, cosyntropin decreased the lateralization index, while metoclopramide did not affect it. The relative gene expression of melanocortin 2, albeit heterogeneous across tumors, was 35% less (P<.0001) in aldosterone-producing adenoma than in the normal adrenal cortex, while dopamine receptor D2 and 5-hydroxytryptamine (serotonin) 4 receptors did not differ between tissues.

CONCLUSION

Cosyntropin, while facilitating ascertainment of selectivity, lessens the lateralization, likely because of a blunted melanocortin 2 expression in aldosterone-producing adenoma. The similar expression of dopamine and 5-hydroxytryptamine (serotonin) 4 receptors in aldosterone-producing adenoma and the normal adrenal cortex can explain why metoclopramide increased the relative aldosterone secretion index on both sides and, therefore, failed to increase the lateralization index.

Aldosterone-Producing Cell Clusters in Normal and Pathological States

Primary aldosteronism (PA) significantly increases the risk of cardiovascular complications, and early diagnosis and targeted treatment based on its pathophysiology is warranted. Next-generation sequencing (NGS) has revealed recurrent somatic mutations in aldosterone-driving genes in aldosterone-producing adenoma (APA). By applying CYP11B2 (aldosterone synthase) immunohistochemistry and NGS to adrenal glands from normal subjects and PA patients, we and others have shown that CYP11B2-positive cells make small clusters, termed aldosterone-producing cell clusters (APCC), beneath the adrenal capsule, and that APCC harbor somatic mutations in genes mutated in APA. We have shown that APCC are increased in CT-negative PA adrenals, while others showed potential progression from APCC to micro APA through mutations. These results suggest that APCC are a key factor for understanding the origin of PA, and further investigation on the relation between APCC and PA is highly needed.

Functional plurihormonal adrenal oncocytoma: case report and literature review

We present a 27-year-old woman with an adrenal oncocytoma. This is a very rare entity. We provide a review of the clinical, biochemical and pathological features of cases reported in the literature.

Confirmatory Tests for the Diagnosis of Primary Aldosteronism: A Prospective Diagnostic Accuracy Study

The diagnosis of primary aldosteronism typically requires at least one confirmatory test. The fludrocortisone suppression test is generally accepted as a reliable confirmatory test, but it is cumbersome. Evidence from accuracy studies of the saline infusion test (SIT) and the captopril challenge test (CCT) has provided conflicting results. This prospective study aimed to evaluate the diagnostic accuracy of the SIT and CCT using fludrocortisone suppression test as the reference standard. One hundred thirty-five patients diagnosed with primary aldosteronism and 101 patients diagnosed with essential hypertension who completed the 3 confirmatory tests were included for the diagnostic accuracy analysis. The areas under the receiver-operator characteristics curves of the CCT and SIT were 0.96 (95% confidence interval [CI], 0.92-0.98) and 0.96 (95% CI, 0.92-0.98), respectively, using post-test plasma aldosterone concentration (PAC) for diagnosis. However, the areas under the receiver-operator characteristics curves of the CCT decreased to 0.71 (95% CI, 0.65-0.77) when the PAC suppression percentage was used to diagnose primary aldosteronism. The optimal cutoff of PAC post-CCT was set at 11 ng/dL, resulting in a sensitivity of 0.90 (95% CI, 0.84-0.95) and a specificity of 0.90 (95% CI, 0.83-0.95), which were not significantly different from those of SIT (with PAC post-SIT set at 8 ng/dL, sensitivity: 0.85 [95% CI, 0.78-0.91], P=0.192; specificity: 0.92 [95% CI, 0.85-0.97], P=0.551). In conclusion, both CCT and SIT are accurate alternatives to the more complex fludrocortisone suppression test. Because CCT is safe and much easier to perform, it may serve as a more feasible alternative. When interpreting the results of CCT, PAC post-CCT is highly recommended.

A case report of hyponatremia after surgery for Conn's adenoma

Primary aldosteronism (PA), also known as Conn's syndrome, is a frequent cause of secondary hypertension. If PA is due to a documented unilateral adrenal adenoma, adrenalectomy is the treatment of choice. Endocrine Society guidelines suggest monitoring potassium after adrenalectomy, while there is no mention of sodium disorders after surgery. Here we report the case of a patient with Conn's syndrome who developed hyponatremia after surgery. This was an unexpected event in the course of the treatment, which sheds light on the fact that low levels of aldosterone strongly influence sodium concentration, and advises clinicians to monitor sodium after adrenalectomy.

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.

The Spectrum of Subclinical Primary Aldosteronism and Incident Hypertension: A Cohort Study

BACKGROUND

Primary aldosteronism is recognized as a severe form of renin-independent aldosteronism that results in excessive mineralocorticoid receptor (MR) activation.

OBJECTIVE

To investigate whether a spectrum of subclinical renin-independent aldosteronism that increases risk for hypertension exists among normotensive persons.

DESIGN

Cohort study.

SETTING

National community-based study.

PARTICIPANTS

850 untreated normotensive participants in MESA (Multi-Ethnic Study of Atherosclerosis) with measurements of serum aldosterone and plasma renin activity (PRA).

MEASUREMENTS

Longitudinal analyses investigated whether aldosterone concentrations, in the context of physiologic PRA phenotypes (suppressed, ≤0.50 µg/L per hour; indeterminate, 0.51 to 0.99 µg/L per hour; unsuppressed, ≥1.0 µg/L per hour), were associated with incident hypertension (defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or initiation of antihypertensive medications). Cross-sectional analyses investigated associations between aldosterone and MR activity, assessed via serum potassium and urinary fractional excretion of potassium.

RESULTS

A suppressed renin phenotype was associated with a higher rate of incident hypertension than other PRA phenotypes (incidence rates per 1000 person-years of follow-up: suppressed renin phenotype, 85.4 events [95% CI, 73.4 to 99.3 events]; indeterminate renin phenotype, 53.3 events [CI, 42.8 to 66.4 events]; unsuppressed renin phenotype, 54.5 events [CI, 41.8 to 71.0 events]). With renin suppression, higher aldosterone concentrations were independently associated with an increased risk for incident hypertension, whereas no association between aldosterone and hypertension was seen when renin was not suppressed. Higher aldosterone concentrations were associated with lower serum potassium and higher urinary excretion of potassium, but only when renin was suppressed.

LIMITATION

Sodium and potassium were measured several years before renin and aldosterone.

CONCLUSION

Suppression of renin and higher aldosterone concentrations in the context of this renin suppression are associated with an increased risk for hypertension and possibly also with increased MR activity. These findings suggest a clinically relevant spectrum of subclinical primary aldosteronism (renin-independent aldosteronism) in normotension.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Calneuron 1 Increased Ca2+ in the Endoplasmic Reticulum and Aldosterone Production in Aldosterone-Producing Adenoma

Aldosterone production is initiated by angiotensin II stimulation and activation of intracellular Ca²⁺ signaling. In aldosterone-producing adenoma (APA) cells, the activation of intracellular Ca²⁺ signaling is independent of the renin-angiotensin-aldosterone systems. The purpose of our study was to clarify molecular mechanisms of aldosterone production related to Ca²⁺ signaling. Transcriptome analysis revealed that the CALN1 gene encoding calneuron 1 had the strongest correlation with CYP11B2 (aldosterone synthase) among genes encoding Ca²⁺-binding proteins in APA. CALN1 modulation and synthetic or fluorescent compounds were used for functional studies in human adrenocortical carcinoma (HAC15) cells. CALN1 expression was 4.4-fold higher in APAs than nonfunctioning adrenocortical adenomas. CALN1 expression colocalized with CYP11B2 expression as investigated using immunohistochemistry in APA and zona glomerulosa of male rats fed by a low-salt diet. CALN1 expression was detected in the endoplasmic reticulum (ER) by using GFP-fused CALN1, CellLight ER-RFP, and the corresponding antibodies. CALN1-overexpressing HAC15 cells showed increased Ca²⁺ in the ER and cytosol fluorescence-based studies. Aldosterone production was potentiated in HAC15 cells by CALN1 expression, and dose-responsive inhibition with TMB-8 showed that CALN1-mediated Ca²⁺ storage in ER involved sarcoendoplasmic reticulum calcium transport ATPase. The silencing of CALN1 decreased Ca²⁺ in ER, and abrogated angiotensin II- or KCNJ5 T158A-mediated aldosterone production in HAC15 cells. Increased CALN1 expression in APA was associated with elevated Ca²⁺ storage in ER and aldosterone overproduction. Suppression of CALN1 expression prevented angiotensin II- or KCNJ5 T158A-mediated aldosterone production in HAC15 cells, suggesting that CALN1 is a potential therapeutic target for excess aldosterone production.

The Potential Role of Primary Care in Case Detection/Screening of Primary Aldosteronism

Endocrine hypertension, particularly primary aldosteronism (PA), was previously considered to account for less than 1% of all hypertension and was suspected only when patients presented with spontaneous hypokalemia. However, the last 20 years of PA research has now clearly shown that PA is not a rarity, but rather, may account for up to 13% of unselected hypertensive individuals and between 10% and 20% of those with resistant hypertension. Most of these patients do not have spontaneous hypokalemia. The population prevalence of PA likely far exceeds actual detection rates in routine clinical care. As PA represents one of the most common, potentially reversible causes of hypertension, and is associated with significant cardiovascular complications over the long term, it is clear that a pragmatic strategy for targeted case detection in primary care is needed.

Coexistence of Primary Hyperaldosteronism and Graves' Disease, a Rare Combination of Endocrine Disorders: Is It beyond a Coincidence-A Case Report and Review of the Literature

BACKGROUND

Primary hyperaldosteronism is a known cause for secondary hypertension. In addition to its effect on blood pressure, aldosterone exhibits proinflammatory actions and plays a role in immunomodulation/development of autoimmunity. Recent researches also suggest significant thyroid dysfunction among patients with hyperaldosteronism, but exact causal relationship is not established. Autoimmune hyperthyroidism (Graves' disease) and primary hyperaldosteronism rarely coexist but underlying mechanisms associating the two are still unclear.

CASE PRESENTATION

A 32-year-old Sri Lankan female was evaluated for new onset hypertension in association with hypokalemia. She also had features of hyperthyroidism together with high TSH receptor antibodies suggestive of Graves' disease. On evaluation of persistent hypokalemia and hypertension, primary hyperaldosteronism due to right-sided adrenal adenoma was diagnosed. She was rendered euthyroid with antithyroid drugs followed by right-sided adrenalectomy. Antithyroid drugs were continued up to 12 months, after which the patient entered remission of Graves' disease.

CONCLUSION

Autoimmune hyperthyroidism and primary hyperaldosteronism rarely coexist and this case report adds to the limited number of cases documented in the literature. Underlying mechanism associating the two is still unclear but possibilities of autoimmune mechanisms and autoantibodies warrant further evaluation and research.

Prognostic Factors of Adrenocortical Carcinoma: An Analysis of the Surveillance Epidemiology and End Results (SEER) Database

Objective: To define the prognostic factors associated with overall survival (OS) and cancer-specific survival (CSS) for adrenocortical carcinoma (ACC). Patients and Methods: We used the Surveillance, Epidemiology and End Results (SEER) database (1973-2014) to identify ACC patients. Correlated variables, including age, sex, race, tumor laterality, marital status at diagnosis, treatment of primary site, lymph node dissection, radiation therapy, chemotherapy, tumor size and tumor stage, were extracted. Univariate and multivariate Cox regression were used to define the prognostic factors. Harrell’s concordance index (C index) was calculated to evaluate the discrimination ability for the prognostic predictive models. Results: There were 749 ACC patients identified from the database. The overall median survival time was 22 (95%CI, 18-25) months. In multivariate analysis, age, treatment, chemotherapy and tumor stage were independent risk factors for both overall and cancer-specific survival. Tumor stage had a dominant effect on the cancer prognosis. Additionally, the ENSAT stage had better discrimination than the AJCC stage group in different predictive models. Conclusion: Our study shows that age, treatment of primary site, chemotherapy and tumor stage were prognostic factors for overall and cancer-specific mortality in ACC patients. Among these factors, tumor stage had a dominant effect. The ENSAT stage was more discriminative than the 7th AJCC stage group. Further multi-center prospective validation is still needed to confirm these outcomes.

Diagnosing and Managing Primary Aldosteronism in Hypertensive Patients: a Case-Based Approach

Primary aldosteronism with a prevalence of 8 % of hypertension and 20 % of pharmacologically resistant hypertension is the most common secondary cause of hypertension. Yet, the diagnosis is missed in the vast majority of patients. Current clinical practice guidelines recommend screening for primary aldosteronism in patients with sustained elevation of blood pressure (BP) ≥150/100 mmHg if possible prior to initiation of antihypertensive therapy, and in patients with resistant hypertension, spontaneous or diuretic-induced hypokalemia, adrenal incidentaloma, obstructive sleep apnea, a family history of early onset of hypertension or cerebrovascular accident <age 40, and first-degree relatives of patients with primary aldosteronism. Clinical and laboratory methods of screening, confirmatory testing, subtype classification, and medical and surgical management are systematically reviewed and illustrated with a clinical case.

Hypertension outcomes of adrenalectomy in patients with primary aldosteronism: a systematic review and meta-analysis

BACKGROUND

The hypertension cure rate of unilateral adrenalectomy in primary aldosteronism (PA) patients varies widely in existing studies.

METHODS

We conducted an observational meta-analysis to summarize the pooled hypertension cure rate of unilateral adrenalectomy in PA patients. Comprehensive electronic searches of PubMed, Embase, Cochrane, China National Knowledge Internet (CNKI), WanFang, SinoMed and Chongqing VIP databases were performed from initial state to May 20, 2016. We manually selected eligible studies from references in accordance with the inclusion criteria. The pooled hypertension cure rate of unilateral adrenalectomy in PA patients was calculated using the DerSimonian-Laird method to produce a random-effects model.

RESULTS

Forty-three studies comprising approximately 4000 PA patients were included. The pooled hypertension cure rate was 50.6% (95% CI: 42.9-58.2%) for unilateral adrenalectomy in PA. Subgroup analyses showed that the hypertension cure rate was 61.3% (95% CI: 49.4-73.3%) in Chinese studies and 43.7% (95% CI: 38.0-49.4%) for other countries. Furthermore, the hypertension cure rate at 6-month follow-up was 53.3% (95% CI: 36.0-70.5%) and 49.6% (95% CI: 40.9-58.3%) for follow-up exceeding 6 months. The pooled hypertension cure rate was 50.9% (95% CI: 40.5-61.3%) from 2001 to 2010 and 50.2% (95% CI: 39.0-61.5%) from 2011 to 2016.

CONCLUSIONS

The hypertension cure rate for unilateral adrenalectomy in PA is not optimal. Large clinical trials are required to verify the utility of potential preoperative predictors in developing a novel and effective prediction model.

Diagnosis and management of primary aldosteronism

Primary aldosteronism (PA) is the most common form of secondary hypertension (HTN), with an estimated prevalence of 4% of hypertensive patients in primary care and around 10% of referred patients. Patients with PA have higher cardiovascular morbidity and mortality than age- and sex-matched patients with essential HTN and the same degree of blood pressure elevation. PA is characterized by an autonomous aldosterone production causing sodium retention, plasma renin supression, HTN, cardiovascular damage, and increased potassium excretion, leading to variable degrees of hypokalemia. Aldosterone-producing adenomas (APAs) account for around 40% and idiopathic hyperaldosteronism for around 60% of PA cases. The aldosterone-to-renin ratio is the most sensitive screening test for PA. There are several confirmatory tests and the current literature does not identify a "gold standard" confirmatory test for PA. In our institution, we recommend starting case confirmation with the furosemide test. After case confirmation, all patients with PA should undergo adrenal CT as the initial study in subtype testing to exclude adrenocortical carcinoma. Bilateral adrenal vein sampling (AVS) is the gold standard method to define the PA subtype, but it is not indicated in all cases. An experienced radiologist must perform AVS. Unilateral laparoscopic adrenalectomy is the preferential treatment for patients with APAs, and bilateral hyperplasia should be treated with mineralocorticoid antagonist (spironolactone or eplerenone). Cardiovascular morbidity caused by aldosterone excess can be decreased by either unilateral adrenalectomy or mineralocorticoid antagonist. In this review, we address the most relevant issues regarding PA screening, case confirmation, subtype classification, and treatment.

Spironolactone in cardiovascular disease: an expanding universe?

Spironolactone has been marketed for over half a century as a ‘potassium-sparing diuretic’, used primarily in patients with ascites. With the realization that primary aldosteronism is the most common (5-13%) form of secondary hypertension, it has become widely used as a mineralocorticoid receptor antagonist. More recently, in the wake of the RALES trial, spironolactone in addition to standard therapy has been shown to be very beneficial in heart failure with a reduced ejection fraction. Despite the failure of the TOPCAT trial, spironolactone is being increasingly used in diastolic heart failure (i.e. with a preserved ejection fraction). The third currently accepted role for spironolactone is in hypertension resistant to three conventional antihypertensives including a diuretic, where it has been proven to be effective, in contra-distinction to renal artery denervation. Finally, brief consideration will be given to ‘areas in waiting’ – pulmonary hypertension/fibrosis, cancer – where spironolactone may play very useful roles.

Adrenal GIPR expression and chromosome 19q13 microduplications in GIP-dependent Cushing's syndrome

GIP-dependent Cushing's syndrome is caused by ectopic expression of glucose-dependent insulinotropic polypeptide receptor (GIPR) in cortisol-producing adrenal adenomas or in bilateral macronodular adrenal hyperplasias. Molecular mechanisms leading to ectopic GIPR expression in adrenal tissue are not known. Here we performed molecular analyses on adrenocortical adenomas and bilateral macronodular adrenal hyperplasias obtained from 14 patients with GIP-dependent adrenal Cushing's syndrome and one patient with GIP-dependent aldosteronism. GIPR expression in all adenoma and hyperplasia samples occurred through transcriptional activation of a single allele of the GIPR gene. While no abnormality was detected in proximal GIPR promoter methylation, we identified somatic duplications in chromosome region 19q13.32 containing the GIPR locus in the adrenocortical lesions derived from 3 patients. In 2 adenoma samples, the duplicated 19q13.32 region was rearranged with other chromosome regions, whereas a single tissue sample with hyperplasia had a 19q duplication only. We demonstrated that juxtaposition with cis-acting regulatory sequences such as glucocorticoid response elements in the newly identified genomic environment drives abnormal expression of the translocated GIPR allele in adenoma cells. Altogether, our results provide insight into the molecular pathogenesis of GIP-dependent Cushing's syndrome, occurring through monoallelic transcriptional activation of GIPR driven in some adrenal lesions by structural variations.

Increased urinary excretion of the epithelial Na channel activator prostasin in patients with primary aldosteronism

OBJECTIVES

Prostasin is a glycosylphosphatidylinositol-anchored serine protease that is released in urine and is involved in epithelial Na channel activation. A direct association between urinary prostasin (u-prostasin) concentration and activation of the aldosterone-driven pathway has been suggested; however, in previous studies on primary aldosteronism, a semiquantitative evaluation, rather than a precise quantification, of prostasin was performed. We aim to investigate if u-prostasin concentrations are higher in patients with primary aldosteronism than in patients with essential hypertension and whether u-prostasin measurements could be a useful marker for diagnosing primary aldosteronism in hypertensive patients.

METHODS

A total of 62 primary aldosteronism and 56 essential hypertension patients were enrolled. Biochemical and hormonal parameters were measured by applying routine laboratory methods, and u-prostasin levels were assessed by ELISA.

RESULTS

Primary aldosteronism patients had higher u-prostasin levels than did essential hypertension patients. Prostasin levels were positively correlated with the aldosterone-to-renin ratio and inversely correlated with plasma K and urinary Na levels. In the highest concentration quartile, u-prostasin levels were associated with a several-fold higher probability of primary aldosteronism diagnosis in hypertensive patients. Receiver operating characteristic curve analysis showed that prostasin was specific but poorly sensitive as a diagnostic marker for primary aldosteronism.

CONCLUSIONS

The study shows that an elevated u-prostasin concentration in humans is a specific marker for primary aldosteronism, which involves the classical model of epithelial Na channel activation. There was no statistically significant difference in prostasin concentrations among patients with different primary aldosteronism subtypes. Studies with a larger series of patients are necessary to clarify the clinical usefulness of the prostasin assay.

Favorable surgical outcomes of aldosterone-producing adenoma based on lateralization by CT imaging and hypokalemia: a non-AVS-based strategy

PURPOSE

To test the efficacy of a strategy based on CT imaging and clinical characteristics on lateralizing origin of excess aldosterone secretion in primary aldosteronism.

PATIENTS AND METHODS

Consecutive patients with diagnosed primary hyperaldosteronism from June 2006 to July 2012 in our center underwent adrenal surgeries without pre-operational adrenal venous sampling (AVS) if all the three criteria were met: (1) round- or oval-shaped occupational lesion of low density after contrast enhancement with diameter >1 cm on CT scan was located in one adrenal gland; (2) unequivocally normal contralateral adrenal gland; (3) serum potassium level lower than 3.5 mmol/L. Subjects who had received operation were taken into analysis and follow-ups.

RESULTS

One hundred and twenty-five patients fulfilled the criteria and were recruited into our research. One hundred and twenty-two operated patients (97.6%) experienced complete resolution of hypokalemia as well as resolution or improvement in hypertension with reduction in antihypertensive medication, while 3 patients (2.4%) failed to obtain normal kalemia and continued on spironolactone therapy. At a median of 65-month (range 21-93) follow-up of these 122 subjects, 27 patients dropped out (22.1%). The 95 responding patients reported no episodes of paralysis or confirmed hypokalemia or any supplementation of potassium. Multivariate linear correlation analysis showed that plasma potassium level was correlated inversely with tumor diameter (r = -0.258, 95% CI -0.076, -0.514, p = 0.037) and basal plasma aldosterone level (r = -0.251, 95% CI -0.040, -0.464, p = 0.042).

CONCLUSIONS

Most patients with typical unilateral adrenal macroadenomas, normal contralateral glands and hypokalemia could attain favorable surgical therapeutic outcomes without pre-operational AVS lateralization.

A Novel Method: Super-selective Adrenal Venous Sampling

Primary aldosteronism (PA) and subclinical Cushing's syndrome (SCS) are conditions in which the adrenal glands autonomously produce excessive amounts of aldosterone and cortisol, respectively. The conventional adrenal venous sampling (cAVS) method collects blood samples from both adrenal central veins and is useful for identifying the laterality of excess hormone production in a unilateral lesion(s), as documented in PA cases. In cAVS, plasma cortisol concentrations (PCCs) are used to normalize plasma aldosterone concentrations (PACs). A novel "super-selective" adrenal venous sampling (ssAVS) method was developed using a micro-catheter, which collects blood samples from adrenal tributary veins (TVs). PACs in ssAVS samples do not require PCC normalization because samples contain a limited amount of systemic venous blood, if any. The ssAVS method enabled segmental lesion(s) to be detected in both adrenal glands, which may be treated by bilateral adrenalectomy, thereby sparing lesion-free segment(s). Right and left adrenals typically have three TVs each, i.e., the superior, lateral, and inferior TVs in the right adrenal as well as the superior-median, superior-lateral, and lateral TVs in the left adrenal. In the ssAVS method, specific parent catheters and a technique to handle them are required, and have been described herein. Furthermore, ssAVS results from three cases of PA are presented: bilateral aldosterone-producing adenoma (APA) (Case #1), left APA and right possible cortisol-producing adenoma causing SCS (Case #2), and idiopathic hyperaldosteronism in which bilateral adrenal segments produced excessive amounts of aldosterone (Case #3). The ssAVS method is not difficult for expert angiographers, and, thus, is recommended worldwide to treat PA cases for which cAVS does not represent a viable surgical treatment option.

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.

Genetic mechanisms of human hypertension and their implications for blood pressure physiology

Hypertension, or elevated blood pressure, constitutes a major public health burden that affects more than 1 billion people worldwide and contributes to ~9 million deaths annually. Hereditary factors are thought to contribute to up to 50% of interindividual blood pressure variability. Blood pressure in the general population approximately shows a normal distribution and is thought to be a polygenic trait. In rare cases, early-onset hypertension or hypotension are inherited as Mendelian traits. The identification of the underlying Mendelian genes and variants has contributed to our understanding of the physiology of blood pressure regulation, emphasizing renal salt handling and the renin angiotensin aldosterone system as players in the determination of blood pressure. Genome-wide association studies (GWAS) have revealed more than 100 variants that are associated with blood pressure, typically with small effect sizes, which cumulatively explain ~3.5% of blood pressure trait variability. Several GWAS associations point to a role of the vasculature in the pathogenesis of hypertension. Despite these advances, the majority of the genetic contributors to blood pressure regulation are currently unknown; whether large-scale exome or genome sequencing studies will unravel these factors remains to be determined.

Adrenal Imaging

Cross-sectional imaging can make a specific diagnosis in lesions, such as myelolipomas, cysts, and hemorrhage, and is often sufficient to distinguish benign from malignant adrenal processes. CT and MRI are useful studies to identify pheochromocytomas and cortisol-secreting or androgen-secreting tumors. In patients with primary aldosteronism, adrenal venous sampling remains the most accurate localizing study and should be performed in all patients older than 35. Radiolabeled isotope studies serve as second-line diagnostic tests for malignant adrenal tumors, primary or metastatic, as well as for pheochromocytoma. Nuclear imaging studies should follow a robust hormonal diagnosis and be correlated with findings on cross-sectional imaging.

Prevalence of primary aldosteronism among patients with type 2 diabetes

CONTEXT

Diabetes and hypertension coexist in 40%-60% of individuals with type 2 diabetes. The coexistence of these two conditions is associated with increased risk of retinopathy, nephropathy and cardiovascular disease.

OBJECTIVE

To investigate the prevalence of primary aldosteronism (PA) in a general cohort of persons with type 2 diabetes.

DESIGN

Cross-sectional study involving six diabetes outpatient clinics in Sweden.

PATIENTS

were enrolled individuals with type 2 diabetes between February 2008 and December 2013.

MEASUREMENTS

Plasma aldosterone concentrations (PAC pmol/L) and direct renin concentrations (DRC mIU/L) were measured. Patients with increased aldosterone renin ratios (ARR) >65 were further evaluated for PA.

RESULTS

Of 578 consecutively screened patients with type 2 diabetes, 27 were treated with mineralocorticoid receptor antagonists (MRA) and potassium-sparing diuretics not further evaluated. Among the remaining 551 patients, 38 had increased ARR, including 22 who were clinically indicated for PA tests and 16 who were not further evaluated due to severe comorbidities and old age. There were five (0.93%) patients with confirmed PA after computerized tomography and adrenal venous sampling. Patients with PA had higher systolic blood pressure (P=.032) and lower potassium levels (P=.027) than those without PA. No significant association was found between plasma aldosterone and diabetic complications.

CONCLUSIONS

The prevalence of PA in an unselected cohort of patients with type 2 diabetes is relatively low, and measures of plasma aldosterone are not strong risk factors for micro- and macrovascular diabetic complications.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

CTNNB1 Mutation in Aldosterone Producing Adenoma

Discoveries of somatic mutations permit the recognition of subtypes of aldosterone-producing adenomas (APAs) with distinct clinical presentations and pathological features. Catenin β1 (CTNNB1) mutation in APAs has been recently described and discussed in the literature. However, significant knowledge gaps still remain regarding the prevalence, clinical characteristics, pathophysiology, and outcomes in APA patients harboring CTNNB1 mutations. Aberrant activation of the Wnt/β-catenin signaling pathway will further modulate tumorigenesis. We also discuss the recent knowledge of CTNNB1 mutation in adrenal adenomas.