Intraindividual Variability of Aldosterone Concentrations in Primary Aldosteronism: Implications for Case Detection

Clinical Management of Primary Aldosteronism: An Update

Despite carrying an excess risk of cardiovascular events, primary aldosteronism (PA) is a commonly overlooked secondary form of arterial hypertension. An increased awareness of its high prevalence and broader screening strategies are urgently needed to improve its detection rate and allow early diagnosis and targeted treatment. For patients with unilateral PA, these measures can correct hyperaldosteronism and ensure cure of hypertension, even when resistant to drug treatment, thus preventing adverse cardiovascular events. Among these, atrial fibrillation is the most common, but left ventricular hypertrophy, stroke, chronic kidney disease, and myocardial infarction also occur more often than in patients with hypertension and no PA. Young patients, who have higher chances of being cured long term, and high-risk patients, such as those with stage III or resistant hypertension, are those who will benefit most from an early diagnosis of PA. Therefore, the implementation of strategies to detect PA by a simplified diagnostic algorithm is necessary. In the patients who seek for surgical cure, adrenal vein sampling is key for the identification of unilateral PA and the achievement of optimal outcomes. Unfortunately, being technically demanding and poorly available, adrenal vein sampling represents the bottleneck in the workup of PA. Considering the novel knowledge generated in the past 5 years in many studies, particularly in the AVIS-2 study (Adrenal Vein Sampling International Study-2), based on 4 decades of experience at our center and on the last guidelines, we herein provide an update on the management of PA with recommendations for drug treatment and strategies to avoid adrenal vein sampling wherever it is poorly, or not, available.

The Spectrum of Dysregulated Aldosterone Production: An International Human Physiology Study

CONTEXT

Primary aldosteronism is a form of low-renin hypertension characterized by dysregulated aldosterone production.

OBJECTIVE

To investigate the contributions of renin-independent aldosteronism and ACTH-mediated aldosteronism in individuals with a low-renin phenotype representing the entire continuum of blood pressure.

DESIGN/PARTICIPANTS

Human physiology study of 348 participants with a low-renin phenotype with severe and/or resistant hypertension, hypertension with hypokalemia, elevated blood pressure and stage I/II hypertension, and normal blood pressure.

SETTING

4 international centers.

INTERVENTIONS/MAIN OUTCOME MEASURES

The saline suppression test (SST) to quantify the magnitude of renin-independent aldosteronism; dexamethasone suppression and ACTH-stimulation tests to quantify the magnitude of ACTH-mediated aldosteronism; adrenal venous sampling to determine lateralization.

RESULTS

There was a continuum of nonsuppressible and renin-independent aldosterone production following SST that paralleled the magnitude of the blood pressure continuum and transcended conventional diagnostic thresholds. In parallel, there was a full continuum of ACTH-mediated aldosteronism wherein post-SST aldosterone levels were strongly correlated with ACTH-stimulated aldosterone production (r = 0.75, P < .0001) and nonsuppressible aldosterone production postdexamethasone (r = 0.40, P < .0001). Beyond participants who met the criteria for primary aldosteronism (post-SST aldosterone of ≥10 ng/dL or ≥277 pmol/L), the continuum of nonsuppressible and renin-independent aldosterone production persisted below this diagnostic threshold, wherein 15% still had lateralizing aldosteronism amenable to surgical adrenalectomy and the remainder were treated with mineralocorticoid receptor antagonists.

CONCLUSION

In the context of a low-renin phenotype, there is a continuum of primary aldosteronism and dysregulated aldosterone production that is prominently influenced by ACTH. A large proportion of individuals with low renin may benefit from aldosterone-directed therapy.

Effects of sodium intake, age, gender, blood sampling time on distribution of plasma aldosterone, renin activity, deoxycorticosterone, cortisol, cortisone, and 24 h urinary aldosterone levels in normotensive individuals based on LC-MS/MS

PURPOSE

This study aims to analyze the distribution of plasma aldosterone, renin activity, deoxycorticosterone (DOC), cortisol, cortisone, and 24 h urinary aldosterone (24 h-uAld) levels based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.

MATERIALS AND METHODS

Plasma and 24 h urine were collected from 129 healthy volunteers in Northeast China. The effect of sodium intake, age, gender, blood sampling time on plasma aldosterone concentration (PAC), plasma renin activity (PRA), PAC to PRA ratio (ARR), DOC, cortisol, cortisone, cortisol to cortisone ratio, and 24 h-uAld were investigated by nonparametric test, multiple linear regression and Harris-Boyd's standard deviate test.

RESULTS

There was no significant difference observed in 24 h-uAld, PAC (AM), PRA(AM), ARR (AM), DOC (AM), cortisol (AM), cortisone (AM), and cortisol to cortisone (AM) between high and low sodium intake group. Significant differences were observed between morning and afternoon sampling groups in terms of PAC, ARR, DOC, cortisol, and cortisone. Reference intervals (RIs) of 24 h-uAld, PAC (AM) were recommended to be partitioned by gender. RI of PRA was recommended age stratification.

CONCLUSION

We recommend that the same reference interval could be used regardless of sodium intake. Gender is the main influence factor for 24 h-uAld, PAC, and ARR. Age is key influence factor for PRA.

Challenges in Diagnosing and Managing the Spectrum of Primary Aldosteronism

Primary aldosteronism, characterized by the dysregulated production of aldosterone from 1 or both adrenal glands, is the most common endocrine cause of hypertension. It confers a high risk of cardiovascular, renal, and metabolic complications that can be ameliorated with targeted medical therapy or surgery. Diagnosis can be achieved with a positive screening test (elevated aldosterone to renin ratio) followed by confirmatory testing (saline, captopril, fludrocortisone, or oral salt challenges) and subtyping (adrenal imaging and adrenal vein sampling). However, the diagnostic pathway may be complicated by interfering medications, intraindividual variations, and concurrent autonomous cortisol secretion. Furthermore, once diagnosed, careful follow-up is needed to ensure that treatment targets are reached and adverse effects, or even recurrence, are promptly addressed. These challenges will be illustrated in a series of case studies drawn from our endocrine hypertension clinic. We will offer guidance on strategies to facilitate an accurate and timely diagnosis of primary aldosteronism together with a discussion of treatment targets which should be achieved for optimal patient outcomes.

Laboratory Testing for Endocrine Hypertension: Current and Future Perspectives

BACKGROUND

Secondary hypertension (SH) is a form of high blood pressure caused by an identifiable underlying condition. Although, it accounts for a small fraction of the overall hypertensive population, detection and management of SH is of utmost importance, because SH phenotypes carry a high cardiovascular risk and can possibly be cured by timely treatment.

CONTENT

This review focuses on the endocrine causes of SH, such as primary aldosteronism, Cushing syndrome, thyroid disease, pheochromocytoma and paraganglioma, acromegaly, and rare monogenic forms. It discusses current biomarkers, analytical methods, and diagnostic strategies, highlighting advantages and limitations of each approach. It also explores the emerging -omics technologies that can provide a comprehensive and multidimensional assessment of SH and its underlying mechanisms.

SUMMARY

Endocrine SH is a heterogeneous and complex condition that requires proper screening and confirmatory tests to avoid diagnostic delays and improve patient outcomes. Careful biomarker interpretation is essential due to potential interferences, variability, and method-dependent differences. Liquid chromatography-tandem mass spectrometry is a superior method for measuring low-concentration hormones and metabolites involved in SH, but it requires expertise. Omics approaches have great potential to identify novel biomarkers, pathways, and targets for SH diagnosis and treatment, especially considering its multifactorial nature.

A novel LC-MS/MS-based assay for the simultaneous quantification of aldosterone-related steroids in human urine

OBJECTIVES

Primary aldosteronism is the most common cause of endocrine hypertension and is associated with significant cardiovascular morbidities. The diagnostic workup depends on determinations of plasma aldosterone and renin which are highly variable and associated with false-positive and false-negative results. Quantification of aldosterone in 24 h urine may provide more reliable results, but the methodology is not well established. We aimed to establish an assay for urinary aldosterone and related steroids with suitability for clinical routine implementation.

METHODS

Here, we report on the development and validation of a quantitative LC-MS/MS method for six urinary steroids: aldosterone, cortisol, 18-hydroxycorticosterone, 18-hydroxycortisol, 18-oxocortisol, tetrahydroaldosterone. After enzymatic deconjugation, total steroids were extracted using SepPak tC18 plates and quantified in positive electrospray ionization mode on a QTRAP 6500+ mass spectrometer.

RESULTS

Excellent linearity was demonstrated with R2>0.998 for all analytes. Extraction recoveries were 89.8-98.4 % and intra- and inter-day coefficients of variations were <6.4 and <9.0 %, establishing superb precision. Patients with primary aldosteronism (n=10) had higher mean 24 h excretions of aldosterone-related metabolites than normotensive volunteers (n=20): 3.91 (95 % CI 2.27-5.55) vs. 1.92 (1.16-2.68) µmol/mol for aldosterone/creatinine, 2.57 (1.49-3.66) vs. 0.79 (0.48-1.10) µmol/mol for 18-hydroxycorticosterone/creatinine, 37.4 (13.59-61.2) vs. 11.61 (10.24-12.98) µmol/mol for 18-hydroxycortisol/creatinine, 1.56 (0.34-2.78) vs. 0.13 (0.09-0.17) µmol/mol for 18-oxocortisol/creatinine, and 21.5 (13.4-29.6) vs. 7.21 (4.88-9.54) µmol/mol for tetrahydroaldosterone/creatinine.

CONCLUSIONS

The reported assay is robust and suitable for routine clinical use. First results in patient samples, though promising, require clinical validation in a larger sample set.

Hyperaldosteronism Screening and Findings From a Large Diverse Population With Resistant Hypertension Within an Integrated Health System

INTRODUCTION

Hyperaldosteronism (HA) is a common cause of secondary hypertension and may contribute to resistant hypertension (RH). The authors sought to determine and characterize HA screening, positivity rates, and mineralocorticoid receptor antagonist (MRA) use among patients with RH.

METHODS

A cross-sectional study was performed within Kaiser Permanente Southern California (7/1/2012-6/30/2017). Using contemporary criteria, RH was defined as blood pressure uncontrolled (≥ 130/80) on ≥ 3 medications or requiring ≥ 4 antihypertensive medications. The primary outcome was screening rate for HA defined as any aldosterone and plasma renin activity measurement. Secondary outcomes were HA screen positive rates and MRA use among all patients with RH. Multivariable logistic regression analysis was used to estimate odds ratio (with 95% confidence intervals) for factors associated with HA screening and for patients that screened positive.

RESULTS

Among 102,480 patients identified as RH, 1977 (1.9%) were screened for HA and 727 (36.8%) screened positive for HA. MRA use was 6.5% among all patients with RH (22.5% among screened, 31.2% among screened positive). Black race, potassium < 4, bicarbonate > 29, chronic kidney disease, obstructive sleep apnea, and systolic blood pressure were associated with HA screening, but only Black race (1.55 [1.20-2.01]), potassium (1.82 [1.48-2.24]), bicarbonate levels (1.39 [1.10-1.75]), and diastolic blood pressure (1.15 [1.03-1.29]) were associated with positive screenings.

CONCLUSION

The authors' findings demonstrate low screening rates for HA among patients with difficult-to-control hypertension yet a high positivity rate among those screened. Factors associated with screening did not always correlate with screening positive. Screening and targeted use of MRA may lead to improved blood pressure control and outcomes among patients with RH.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Aldosterone-to-renin ratio (ARR) as a screening tool for primary aldosteronism (PA)

The aldosterone-to-renin ratio (ARR) is the standard screening test for primary aldosteronism (PA). Because of the poor reproducibility of the ARR, repeat testing is recommended if the result is not compatible with the clinical condition. Various methods to measure renin are used in different hospitals in Taiwan, and the ARR cutoff values also differ among laboratories. The Task Force of Taiwan PA recommend using plasma renin activity (PRA) to calculate ARR instead of direct renin concentration (DRC) unless PRA is unavailable, because PRA is widely used in international guidelines and most studies.

Adrenal Vein Sampling: Does the Location of the Non-adrenal Venous Sample Matter?

PURPOSE

Adrenal vein sampling (AVS) is used to lateralise and differentiate unilateral from bilateral aldosterone production in primary aldosteronism. The adrenal venous samples are standardised to a peripheral or low inferior vena cava (IVC) sample and compared. It is unknown whether the location of the non-adrenal sample affects the results. This study compares AVS results standardised to the low IVC and right external iliac vein (REIV).

METHODS

Patients who underwent AVS between March 2021 and May 2023 were included. All procedures were undertaken by a single operator (AA). Demographic data and AVS results were collected from patients' electronic records. Catheterisation success and lateralisation were assessed using both low IVC and REIV samples. Equivalence test was used to compare the cortisol and aldosterone levels.

RESULTS

Eighty-one patients, (M: F = 38:43), aged between 29 and 74 were included. Bilateral successful adrenal vein cannulation was achieved in 79/81 (97.5%) cases. The mean cortisol levels from the REIV were statistically equivalent although there was a small and not biologically significant difference from the low IVC (respective geometric means 183 nmol/l vs. 185 nmol/l, p = 0.015). This small difference in cortisol may be due to accessory adrenal venous drainage into the IVC. The aldosterone and aldosterone/cortisol ratios were statistically equivalent. There was no discordance in selectivity or lateralisation when the IVC or REIV measurements were used.

CONCLUSION

The IVC and REIV samples may be used interchangeably during AVS.

Subclinical Primary Aldosteronism and Cardiovascular Health: A Population-Based Cohort Study

BACKGROUND

Primary aldosteronism, characterized by overt renin-independent aldosterone production, is a common but underrecognized form of hypertension and cardiovascular disease. Growing evidence suggests that milder and subclinical forms of primary aldosteronism are highly prevalent, yet their contribution to cardiovascular disease is not well characterized.

METHODS

This prospective study included 1284 participants between the ages of 40 and 69 years from the randomly sampled population-based CARTaGENE cohort (Québec, Canada). Regression models were used to analyze associations of aldosterone, renin, and the aldosterone-to-renin ratio with the following measures of cardiovascular health: arterial stiffness, assessed by central blood pressure (BP) and pulse wave velocity; adverse cardiac remodeling, captured by cardiac magnetic resonance imaging, including indexed maximum left atrial volume, left ventricular mass index, left ventricular remodeling index, and left ventricular hypertrophy; and incident hypertension.

RESULTS

The mean (SD) age of participants was 54 (8) years and 51% were men. The mean (SD) systolic and diastolic BP were 123 (15) and 72 (10) mm Hg, respectively. At baseline, 736 participants (57%) had normal BP and 548 (43%) had hypertension. Higher aldosterone-to-renin ratio, indicative of renin-independent aldosteronism (ie, subclinical primary aldosteronism), was associated with increased arterial stiffness, including increased central BP and pulse wave velocity, along with adverse cardiac remodeling, including increased indexed maximum left atrial volume, left ventricular mass index, and left ventricular remodeling index (all P<0.05). Higher aldosterone-to-renin ratio was also associated with higher odds of left ventricular hypertrophy (odds ratio, 1.32 [95% CI, 1.002-1.73]) and higher odds of developing incident hypertension (odds ratio, 1.29 [95% CI, 1.03-1.62]). All the associations were consistent when assessing participants with normal BP in isolation and were independent of brachial BP.

CONCLUSIONS

Independent of brachial BP, a biochemical phenotype of subclinical primary aldosteronism is negatively associated with cardiovascular health, including greater arterial stiffness, adverse cardiac remodeling, and incident hypertension.

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

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

Practical recommendations for antihypertensive therapy during the primary aldosteronism screening test

BACKGROUND

The aldosterone-to-renin activity ratio (ARR) is recommended as a screening test for primary aldosteronism (PA). The use of antihypertensive medication is one of the most important factors to take into account when interpreting the ARR.

OBJECTIVES

The goal of this study was to compare the effect of various antihypertensive drug classes on biochemical testing and provide practical recommendations for antihypertensive medication regimens in patients suspected of having PA.

METHODS

We retrospectively investigated 4218 hypertensive patients who underwent PA detection between January 2020 and February 2023. Finally, 25 patients with essential hypertension (EH) and 39 with PA were involved. The enrolled EH patients were selected from EH patients with at least two screening tests with interfering medication changes for at least 4 weeks.

RESULTS

A total of 2/18 (11.1%) EH patients had opposite screening results after angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs), dihydropyridine-calcium channel blockers (DHP-CCBs) and diuretics were withdrawn. A total of 3/3 (100%) of the patients were initially screened as positive but had results that tested negative after β-blockers withdrawal. A total of 3/39 (7.7%) PA patients were misdiagnosed with EH with drug effects. Only plasma renin activity was markedly reduced after antihypertensive medication washout (P = 0.0173).

CONCLUSIONS

Not every patient receiving β-blockers, ACEIs, ARBs and DHP-CCBs with negative reports needed withdrawal or switching antihypertensive drugs. We recommend that patients be left on a regimen that includes β-blockers, ACEIs, ARBs, DHP-CCBs and spironolactone when determining the ARR during the initial test.

Who and How Should We Screen for Primary Aldosteronism?

There are mounting data that at least 30% of hypertensives who are appropriately screened have primary aldosteronism (PA), rather than the commonly reported figure of 5% to 10%. Second, there are similar data that undertreated patients with PA have a 3-fold higher risk profile than essential hypertensives with the same blood pressure levels. Third, clinicians managing hypertension measure success as sustainable lowering of blood pressure; untreated hypertensive patients with PA are thus in double jeopardy. Finally, and crucially, fewer than 1% of patients with hypertension are ever screened-let alone investigated-for PA. Accordingly, for "Who should we screen?" the answer is simple-all patients with hypertension. For "How they should be screened?" the answer is also simple-add spironolactone 25 mg/day for 4 weeks and measure the blood pressure response. In established hypertension, a fall of <10 mm Hg means PA is unlikely; above 12 mm Hg PA, it is probable. Newly presenting hypertension is much the same-hold off on first-order antihypertensive(s) and prescribe spironolactone 25 mg/day for 4 weeks. If blood pressure falls into the normal range, continue; if it does not, prescribe a standard antihypertensive. It is likely that the above protocols-a first start, amenable to refinement-will find additional hypertensives with unilateral PA; it is probable that the overwhelming majority will have bilateral disease. What this means is that we have a major public health issue on our hands: how can this be the case?

A novel clinical-imaging nomogram for predicting primary aldosteronism in patients with hypertension

This study aimed to develop and validate the accuracy of a clinical-imaging index nomogram in predicting primary aldosteronism (PA) in patients with hypertension. This case-control study enrolled 404 hypertension patients in the First Affiliated Hospital of Nanjing Medical University, China, from April 2017 to September 2021. The patients were randomly divided into the training set (n = 283, 70%) and the validation set (n = 121, 30%). Univariate and multivariate logistic regression analyses were performed to identify independent predictors of PA, which were then used construct a nomogram. The receiver operating characteristic (ROC) curve and calibration plot were drawn to assess the predictive value. The accuracies of our nomogram and other known prediction models were compared using decision curve analyses (DCA). Four significant variables (history of hypokalemia [OR = 2.684, 95% CI: 1.281-5.623, P < 0.001], typical imaging feature [OR = 2.316, 95% CI: 1.166-4.601, P = 0.003], 24 h urine potassium [OR = 0.956, 95% CI: 0.932-0.980, P < 0.001], plasma renin activity [PRA] [OR = 1.423, 95% CI: 1.161-1.744, P < 0.001]) in the multivariate logistic regression analysis were sifted out, and used to build the nomogram. The predictive nomogram yielded an AUC of 0.890 (95% CI, 0.853-0.927) in the training set and 0.860 (95% CI, 0.793-0.927) in the validation set. Predicted and actual probability of PA matched well in the nomogram. Moreover, the DCA showed that the nomogram gained a net benefit in clinical practice in predicting PA when the threshold value was set between 0.1 and 1.0. Our four-variable nomogram was accurate in predicting PA patients and might be introduced into clinical management.

Redefining primary hyperaldosteronism as "The Syndrome of Inappropriate Aldosterone Secretion (SIALDS)": A common but unrecognized cause of hypertension

The current screening and diagnostic recommendations for detecting Primary Hyperaldosteronism (PHA) focus on diagnosing the more severe and overt instances of renin-independent aldosterone production. However, milder forms of autonomous aldosterone secretion have been demonstrated to exist below the diagnostic thresholds of current PHA guidelines, and associate with clinically relevant cardiovascular risk. PHAencompasses a spectrum of renin independent aldosterone production, progressing from a subclinical state in normotensives to a full-blown clinical syndrome representing the resistant hypertension population. The authors propose the Syndrome of Inappropriately Elevated Aldosterone Secretion (SIALDS) concept as a potential new paradigm for understanding and diagnosing PHA and expanded diagnostic approach to improve early detection even in well-controlled hypertension. The authors also delve into the impact of treatments, including mineralocorticoid receptor antagonists and emerging aldosterone synthase inhibitors. Furthermore, The authors outline future research directions, proposing clinical trials to investigate the long-term identification and treatment outcomes of SIALDS.

Primary Aldosteronism Prevalence - An Unfolding Story

Primary aldosteronism (PA) is characterized by dysregulated, renin-independent aldosterone excess. Long perceived as rare, PA has emerged as one of the most common causes of secondary hypertension. Failure to recognize and treat PA results in cardiovascular and renal complications, through processes mediated by both direct target tissue insults and indirectly, by hypertension. PA spans a continuum of dysregulated aldosterone secretion, which is typically recognized in late stages after treatment-resistant hypertension and cardiovascular and/or renal complications develop. Determining the precise disease burden remains challenging due to heterogeneity in testing, arbitrary thresholds, and populations studied. This review summarizes the reports on PA prevalence among the general population and in specific high-risk subgroups, highlighting the impact of rigid versus permissive criteria on PA prevalence perception.

Biochemical Evaluation by Confirmatory Tests after Unilateral Adrenalectomy for Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. Unilateral PA can be cured using unilateral adrenalectomy (Adx). PA surgery outcome (PASO) criteria, which include clinical and biochemical outcomes, have been proposed to evaluate PA cure after Adx. However, clinical outcomes are often inconsistent with biochemical outcomes. In addition, although confirmatory tests are included as endpoints of biochemical outcomes in the PASO criteria, their clinical usefulness has not yet been established. We evaluated clinical parameters and confirmatory test results before and after Adx in 16 patients with PA and assessed the usefulness of the confirmatory tests. The following were the clinical outcomes after Adx: 37.5% complete success, 62.5% partial success, and 0% absent success. The ratio of biochemical complete success was as follows: 69% aldosterone/renin ratio and basal plasma aldosterone concentration, 19% as assessed by the captopril challenge test, 47% as assessed by the saline infusion test, 30% as assessed by the furosemide upright test, and 100% urine aldosterone. Of these, biochemical complete success was judged in four cases by aldosterone/renin ratio and basal plasma aldosterone concentration, one case by captopril challenge test, five cases by saline infusion test, and one case by furosemide upright test. Although clinical outcomes and urine aldosterone levels improved after Adx, confirmatory tests failed to improve in some cases. The current criteria are not considered useful for biochemical evaluation after Adx. To determine whether additional treatment with mineralocorticoid receptor antagonists is required, more accurate biochemical criteria should be established after Adx.

Accuracy of Gallium-68 Pentixafor Positron Emission Tomography-Computed Tomography for Subtyping Diagnosis of Primary Aldosteronism

IMPORTANCE

Adrenal vein sampling (AVS) is the recommended procedure for subtyping primary aldosteronism (PA) as unilateral PA (UPA) or bilateral PA (BPA), with different treatment needed for each: adrenalectomy for UPA and medication for BPA. However, AVS is invasive and technically difficult, and how to subtype PA noninvasively is currently a great challenge.

OBJECTIVE

To evaluate the accuracy of gallium-68 pentixafor positron emission tomography-computed tomography (PET-CT) in subtyping PA using AVS as a reference standard.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted at a tertiary hospital in China among patients diagnosed with PA. Enrollment was started in November 2021, with follow-up ending in May 2022.

EXPOSURES

: Patients were recruited to undergo gallium-68 pentixafor PET-CT and AVS.

MAIN OUTCOMES AND MEASURES

Maximum standardized uptake value (SUVmax) of each adrenal gland during PET-CT was measured to calculate the lateralization index of SUVmax. Area under the receiver operating characteristic curve (AUROC), specificity, and sensitivity were used to analyze the accuracy of the lateralization index based on SUVmax for subtyping PA.

RESULTS

Among 100 patients with PA who completed the study (47 female [47.0%] and 53 male [53.0%]; median [IQR] age, 49 [38-56] years), 43 individuals had UPA and 57 individuals had BPA. Aldosterone-cortisol ratio (Spearman ρ = 0.26; P < .001) in adrenal veins was positively correlated with SUVmax of adrenal glands at 10 minutes during PET-CT. Using lateralization index based on SUVmax at 10 minutes to identify UPA, the AUROC was 0.90 (95% CI, 0.83-0.97). A cutoff value for lateralization index based on SUVmax at 10 minutes set at 1.65 conferred a specificity of 1.00 (95% CI, 0.94-1.00) and sensitivity of 0.77 (95% CI, 0.61-0.88). The diagnostic concordance rate of PET-CT and AVS was 90 patients (90.0%) compared with 54 patients (54.0%) between traditional CT and AVS.

CONCLUSIONS AND RELEVANCE

This study found good diagnostic accuracy of gallium-68 pentixafor PET-CT in differentiating UPA from BPA. These findings suggest that gallium-68 pentixafor PET-CT may be used to avoid invasive AVS in some patients with PA.

Impact of Conducting Adrenal Venous Sampling in the Morning Versus Afternoon in Primary Aldosteronism

Context

Adrenal venous sampling (AVS) is the gold standard technique for subtype differentiation of primary aldosteronism (PA) and to obtain aldosterone and cortisol measurements; however, their secretion patterns show fluctuations during the day.

Objective

We aimed to examine the effects of AVS timing on AVS results.

Methods

This multicenter, retrospective, observational study included a total of 753 patients who were diagnosed with PA and underwent AVS in 4 centers in Japan. Among them, 504 and 249 patients underwent AVS in the morning (AM-AVS) and in the afternoon (PM-AVS), respectively. The outcome measures were the impact of AVS timing and hormone fluctuations in a day on AVS results.

Results

There were no differences in the success rate of AVS, diagnostic rate of disease type, or frequency of discrepancy in PA subtypes between the AM-AVS and PM-AVS groups. Regarding patients with unilateral PA, aldosterone concentrations in adrenal venous blood did not differ between the 2 groups on the dominant or nondominant side. Conversely, regarding patients with bilateral PA, aldosterone concentrations in adrenal venous blood were significantly higher in the AM-AVS than in the PM-AVS group.

Conclusions

The timing of AVS did not seem to have a significant impact on subtype diagnosis. The aldosterone levels in adrenal venous blood were significantly higher in patients with bilateral PA in the AM-AVS group, but there was no such difference between patients with unilateral PA in the AM-AVS and PM-AVS groups. Each subtype may have a different hormone secretion pattern in a day.

Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism

CONTEXT

The plasma aldosterone concentration (PAC), renin, and aldosterone-to-renin ratio (ARR) are used to screen for primary aldosteronism (PA). Substantial intra-individual variability of PAC and ARR using plasma renin activity in the context of usual antihypertensive therapy has been described, but there is no data on ARR variability calculated using direct renin concentration (DRC).

OBJECTIVE

To describe the intra-individual variability of PAC, DRC, and ARR in the absence of interfering medications in patients with and without PA.

DESIGN

Retrospective cohort study.

PATIENTS

Hypertensive patients referred for investigation of PA, with at least 2 ARR measurements while off interfering medications.

SETTING

Endocrine hypertension service of a tertiary center, from May 2017 to July 2021.

MAIN OUTCOME MEASURES

PAC, DRC, and ARR variability was calculated as coefficient of variation (CV) and percent difference (PD).

RESULTS

Analysis of 223 patients (55% female, median age 52 years), including 162 with confirmed PA, demonstrated high variability with a sample CV of 22-25% in the PAC and sample CV of 41% to 42% in the DRC and ARR in both the PA and non-PA groups. The degree of variability was substantially higher than the assays' analytical CV. Sixty-two patients (38%) with PA had at least one ARR below 70 pmol/L:mU/L (2.4 ng/dL:mU/L), a cut-off for first-line screening of PA.

CONCLUSIONS

Significant intra-individual variability in PAC, DRC, and hence ARR occurs in a large proportion of patients being investigated for PA. These findings support the need for at least 2 ARR before PA is excluded or further investigated.

Primary Aldosteronism: State-of-the-Art Review

We are witnessing a revolution in our understanding of primary aldosteronism (PA). In the past 2 decades, we have learned that PA is a highly prevalent syndrome that is largely attributable to pathogenic somatic mutations, that contributes to cardiovascular, metabolic, and kidney disease, and that when recognized, can be adequately treated with widely available mineralocorticoid receptor antagonists and/or surgical adrenalectomy. Unfortunately, PA is rarely diagnosed, or adequately treated, mainly because of a lack of awareness and education. Most clinicians still possess an outdated understanding of PA; from primary care physicians to hypertension specialists, there is an urgent need to redefine and reintroduce PA to clinicians with a modern and practical approach. In this state-of-the-art review, we provide readers with the most updated knowledge on the pathogenesis, prevalence, diagnosis, and treatment of PA. In particular, we underscore the public health importance of promptly recognizing and treating PA and provide pragmatic solutions to modify clinical practices to achieve this.

Intraindividual variability of serum aldosterone and its implication for primary aldosteronism screening

CONTEXT

Primary aldosteronism (PA) screening relies on an elevated aldosterone to renin ratio with a minimum aldosterone level, which varies from 10 to 15 ng/dL (277 to 415.5 pmol/L) using immunoassay.

AIM

To evaluate intraindividual coefficient of variation (CV) of aldosterone and aldosterone to direct renin concentration ratio (A/DRC) and its impact on PA screening.

METHODS

A total of 671 aldosterone and DRC measurements were performed by the same chemiluminescence assays in a large cohort of 216 patients with confirmed PA and at least two screenings.

RESULTS

The median intraindividual CV of aldosterone and A/DRC was 26.8% and 26.7%. Almost 40% of the patients had at least one aldosterone level <15 ng/dL, 19.9% had at least two aldosterone levels <15 ng/dL and 16.2% had mean aldosterone levels <15 ng/dL. A lower cut-off of 10 ng/dL was associated with false negative rates for PA screening of 14.3% for a single aldosterone measurement, 4.6% for two aldosterone measurements and only 2.3% for mean aldosterone levels. Considering the minimum aldosterone, true positive rate of aldosterone thresholds was 85.7% for 10 ng/dL and 61.6% for 15 ng/dL. An A/DRC >2 ng/dL/µIU/mL had a true positive rate for PA diagnosis of 94.4% and 98.4% when based on one or two assessments, respectively. CV of aldosterone and A/DRC were not affected by sex, use of interfering anti-hypertensive medications, PA lateralization, hypokalemia, age and number of hormone measurements.

CONCLUSION

Aldosterone concentrations had a high CV in PA patients, which results in an elevated rate of false negative test in a single screening for PA. Therefore, PA screening should be based in at least two screenings with concomitant aldosterone and renin measurements.

Variability of aldosterone, renin and the aldosterone-to-renin ratio in hypertensive patients without primary aldosteronism

OBJECTIVES

The aldosterone-to-renin ratio (ARR) is commonly used in the screening of primary aldosteronism. However, limited information is available with regard to the intra-patient variability in this ratio. Our objective is to determine whether ARR measurements are reliably consistent over both the short- and long-term.

METHODS

We assessed the short-term variability of the aldosterone-to-renin ratio in 116 unmedicated, essential hypertensive participants who had two blood samples taken in the morning of the same day for measurement of aldosterone and active plasma renin concentration. Long-term variability was studied in 22 unmedicated, essential hypertensive participants who had two blood samples taken approximately 1 year apart. All samples were taken under highly standardized conditions.

RESULTS

Our data show that renin, aldosterone and the aldosterone-to-renin ratio show marked variations, both when measured on the same day and when assessed at a longer interval. The ARR becomes increasingly variable as its mean value increases. Its degree of variability is similar in both the short-term and the long-term.

CONCLUSIONS

Based on our findings, we conclude that the aldosterone-to-renin has acceptable short-term variability in the lower ranges, but increasingly dubious reliability as aldosterone-to-renin values rise. Thus, in a clinical context, great caution should be taken in interpreting point-measurements of moderate to high aldosterone-to-renin ratio values.

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.

Aldosterone in chronic kidney disease and renal outcomes

AIMS

Randomized controlled trials have demonstrated the efficacy of mineralocorticoid receptor (MR) antagonism in delaying chronic kidney disease (CKD) progression in diabetes; however, they have not investigated the role of aldosterone or whether these beneficial effects could be achieved in individuals without diabetes.

METHODS AND RESULTS

The association between serum aldosterone concentrations and kidney disease progression was investigated among 3680 participants in the Chronic Renal Insufficiency Cohort. The primary outcome was CKD progression [defined as the composite of 50% decline in estimated glomerular filtration rate (eGFR) or end-stage kidney disease, whichever occurred first]. The associations between serum aldosterone and kidney disease outcomes were assessed using Cox proportional hazard models. At baseline, higher aldosterone concentrations were associated with a lower eGFR, lower serum potassium, greater urinary potassium, and protein excretion. Over a median follow-up of 9.6 years, 1412 participants developed CKD progression. In adjusted models, each doubling of serum aldosterone was associated with a 11% increased risk of CKD progression [hazard ratio (HR) 1.11, 95% confidence interval (CI) 1.04-1.18]. Individuals with the highest quartile of serum aldosterone had a 45% increased risk of CKD progression (HR 1.45, 95% CI 1.22-1.73) compared with the lowest quartile. The risk for CKD progression was similar regardless of whether patients had concomitant diabetes (P-interaction = 0.10).

CONCLUSION

Higher serum aldosterone levels among individuals with CKD are independently associated with an increased risk for kidney disease progression, irrespective of concomitant diabetes. These findings provide mechanistic support for MR antagonists in delaying CKD progression and suggest that they may also have a role in those without diabetes.

Analytical evaluation and bioclinical validation of new aldosterone and renin immunoassays

OBJECTIVES

Aldosterone and renin determinations play an important role in the etiological diagnosis of secondary hypertension. The analytical performances of new aldosterone and renin immunoassays on the Lumipulse G600II^® system (Fujierbio) were investigated and compared with those of the iSYS^® system (IDS) on patients concerned by medical investigations in a context of suspected or proven Primary aldosteronism.

METHODS

By using the Lumipulse^® G Aldosterone and Renin assays we performed imprecision study, linearity and method comparison (n=107). Accuracy of this new renin assay was tested using the International Standard (WHO IS 68/356). We also assessed the equivalence of the different samples types (n=29).

RESULTS

The imprecision evaluation showed all CVs <3% and <6% for Lumipulse^® G Aldosterone and Renin assays respectively. The linearity was excellent over the clinical range and the comparison with the iSYS^® assays (n=79) showed a strong correlation (R²=1) despite a slight tendency to underestimation (bias of -17.53 pg/mL or 48.56 pmol/L for aldosterone and -15.395 pg/mL for renin). Moreover, the contingency studies based on diagnostic criteria showed that Lumipulse^® G results lead to the same clinical diagnosis that iSYS^® results. A clear correlation was obtained between EDTA and heparin plasma as well as with the serum for all range of measures.

CONCLUSIONS

The Lumipulse^® G Aldosterone and Renin assays present performances compatible with a routine use in medical laboratories. The precise quantification in the low range can be of interest in some clinical contexts especially standing/laying tests. However, the standardisation against the WHO International Standard Renin would be advisable.

Cardiac Structure and Function Across the Spectrum of Aldosteronism: the Atherosclerosis Risk in Communities Study

BACKGROUND

Aldosterone production and mineralocorticoid receptor activation are implicated in myocardial fibrosis and cardiovascular events.

METHODS

Cardiac structure and function were assessed in 4547 participants without prevalent heart failure (HF) in the ARIC study (Atherosclerosis Risk in Communities), with echocardiography, aldosterone, and plasma renin activity measurement (2011-2013). Subjects were characterized by plasma renin activity as suppressed (≤0.5 ng/mL per hour) or unsuppressed (>0.5 ng/mL per hour). Cross-sectional relationships with cardiac structure and function, and longitudinal relationships with outcomes (HF hospitalization; HF and all-cause death; HF, death, myocardial infarction, and stroke; and incident atrial fibrillation) were assessed. Models were adjusted for demographic and anthropometric characteristics and additively, for blood pressure and antihypertensives.

RESULTS

Evidence of primary aldosteronism physiology was prevalent (11.6% with positive screen) and associated with echocardiographic parameters. Renin suppression was associated with greater left ventricular mass, left ventricular volumes, and left atrial volume index, and a lower E/A ratio (adjusted P<0.001 for all). Higher aldosterone was associated with greater left ventricular mass and lower global longitudinal strain and lateral E'. The highest tertile of aldosterone was associated with a hazard ratio of 1.37 (95% CI, 1.06-1.77; 5.5-year follow-up) for incident atrial fibrillation relative to the lowest. Renin suppression was associated with HF (hazard ratio, 1.34 [95% CI, 1.05-1.72]; 7.3-year follow-up), although these relationships did not remain statistically significant after additional adjustment for hypertension.

CONCLUSIONS

Renin suppression and aldosterone excess, consistent with primary aldosteronism pathophysiology, were associated with cardiac structural and functional alterations and may represent an early target for mitigation of fibrosis with mineralocorticoid receptor antagonists.

Recalibrating Interpretations of Aldosterone Assays Across the Physiologic Range: Immunoassay and Liquid Chromatography-Tandem Mass Spectrometry Measurements Under Multiple Controlled Conditions

Context

Clinicians frequently rely on aldosterone thresholds derived from older immunoassays to diagnose primary aldosteronism. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is increasingly widespread and reported to yield lower aldosterone concentrations.

Objective

Given the health impact of incorrect interpretations of aldosterone levels, we compared measurements using LC-MS/MS and immunoassay across the full range of aldosterone physiology by evaluating distinct regulation by angiotensin II and adrenocorticotropin (ACTH).

Methods

Normotensive volunteers underwent prospective characterization of aldosterone production by immunoassay and LC-MS/MS during 4 conditions (n = 188): oral sodium suppression and restriction (to assess angiotensin II-mediated aldosterone production) and dexamethasone suppression and cosyntropin stimulation (to assess ACTH-mediated aldosterone production).

Results

Serum aldosterone concentrations by LC-MS/MS and immunoassay had a correlation of 0.69 (P < .001), with good agreement (intraclass correlation 0.76; 95% CI 0.52-0.87). Aldosterone was lower by LC-MS/MS than immunoassay (median 10.5 [3.8, 21.9] vs 19.6 [9.5, 28.0] ng/dL; P < .001), with an average difference of 37.2%. The most notable discrepancy was in the clinically discriminatory range <20 ng/dL: 9.9 (7.1, 13.8) ng/dL using immunoassay corresponded to 5.5 (1.4, 8.9) ng/dL by LC-MS/MS (P < .001). Following oral sodium suppression, the aldosterone-to-renin ratio was 4-fold higher using immunoassay (27.2 [19.7, 62.4] vs 6.4 [3.5, 19.1] ng/dL per ng/mL/hour; P < .001).

Conclusion

Aldosterone measurements are substantially lower by LC-MS/MS than immunoassay across the full physiologic range, especially when aldosterone levels were less than 20 ng/dL. These findings highlight the need to recalibrate diagnostic interpretations when measuring aldosterone via LC-MS/MS and provide insights into potential biologic causes of assay differences.

Performance of the aldosterone-to-renin ratio as a screening test for primary aldosteronism in primary care

Primary aldosteronism (PA) is the most common and potentially curable form of secondary hypertension, affecting 5-10% of primary care patients with hypertension. Primary care physicians have an important role in initiating the screening for PA in patients with hypertension and referring to a specialist service depending on the screening test results. The currently recommended screening test for PA is the plasma aldosterone-to-renin ratio (ARR). Test results are influenced by medications so careful patient preparation is required including adjusting existing antihypertensive medications to avoid diagnostic errors. A range of laboratory method-dependent ARR thresholds are used for the screening of PA around the world. Periodic clinical audits and case reviews by clinicians and the laboratory may help refine the local thresholds. Patients with an abnormally elevated ARR should be referred to a specialist for confirmatory testing while patients with a high pre-test probability but a normal ARR could have a repeat test in view of the within-individual variability. Despite the heterogenous ARR thresholds, measuring the ARR is still more likely to detect PA than not screening at all.

Prevalence of primary aldosteronism in type 2 diabetes mellitus and hypertension: A prospective study from Western India

OBJECTIVE

Type 2 diabetes mellitus (T2DM) and hypertension commonly coexist; however, underlying primary aldosteronism (PA) can lead to worsening of hypertension, glycemia and cardiovascular risk. We aim to screen patients with T2DM and hypertension for PA by conducting a prospective monocentric study from Western India, which included adults with T2DM and hypertension from the outpatient diabetes clinic.

DESIGN

Prospective study.

PATIENTS AND MEASUREMENTS

Patients with an aldosterone renin ratio of ≥1.6 ng/dl/µIU/ml with plasma aldosterone concentration (PAC) ≥ 10 ng/dl were considered to be positive on a screening test. A PAC ≥ 6 ng/dl on seated saline suppression test (SST) was used to confirm the diagnosis of PA.

RESULTS

Four hundred and eighty-six patients were included in this study. Seventy-six (15.6%, 95% confidence interval [CI]: 12.7%-19.1%) patients had a positive screening test with positive confirmatory test in 20 of the 36 (55.5%, 95% CI: 39.3%-71.7%) screen-positive patients who underwent SST. Patients with positive screening test had a higher proportion of females (65.8% vs. 50%; p = .011), frequent history of hypertensive crises (21.1% vs. 8%; p = .001), uncontrolled blood pressure (51.3% vs. 34.6%; p = .006), diagnosis of hypertension before diabetes (32.9% vs. 21.7%; p = .035) and higher systolic (137.6 ± 6.9 vs. 131.2 ± 17.8 mmHg; p = .004) and diastolic (85.3 ± 11.1 vs. 81.7 ± 10.7 mmHg; p = .007) blood pressures. Patients with positive confirmatory test had longer duration of diabetes (108 [60-162] vs. 42 [24-87] months; p = .012), hypertension (84 [42-153] vs. 36 [15-81] months; p = .038) and higher creatinine (1.16 [1.02-1.42] vs. 0.95 [0.84-1.12] mg/dl; p = .021).

CONCLUSIONS

PA is prevalent (at least 4.1%) in Asian Indian patients with T2DM and hypertension. Further studies are needed to assess the cost-effectiveness of routine screening.

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.

Primary Aldosteronism: Where Are We Now? Where to From Here?

Primary aldosteronism, the most common secondary form of hypertension, is thought to be present in ≈5% to 10% of hypertensive adults. However, recent studies indicate that its prevalence may be at least 3-fold higher based on the identification of renin-independent (autonomous) aldosterone production that is not suppressible with dietary sodium loading in a large fraction of adults with primary hypertension. Currently, the screening rate for primary aldosteronism in adults with primary hypertension is <1%. This review summarizes current thinking about primary aldosteronism from the standpoint of 3 key questions: Where are we now? Where to from here? So how do we get there?

Pathophysiology and histopathology of primary aldosteronism

Primary aldosteronism (PA) can be sporadic or familial and classified into unilateral and bilateral forms. Sporadic PA predominates with excessive aldosterone production usually arising from a unilateral aldosterone-producing adenoma (APA) or bilateral adrenocortical hyperplasia. Familial PA is rare and caused by germline variants, that partly correspond to somatic alterations in APAs. Classification into unilateral and bilateral PA determines the treatment approach but does not accurately mirror disease pathology. Some evidence indicates a disease continuum ranging from balanced aldosterone production from each adrenal to extreme asymmetrical bilateral aldosterone production. Nonetheless, surgical removal of the overactive adrenal in unilateral PA achieves highly successful outcomes and almost all patients are biochemically cured of their aldosteronism.

Primary Aldosteronism, Aldosterone, and Extracellular Vesicles

Primary aldosteronism (PA) is an endocrine related condition leading to arterial hypertension due to inappropriately high and unregulated aldosterone concentration. Recently, a broad spectrum of PA has been recognized, which brings new challenges associated with early identification of this condition that affect renal epithelial and extrarenal tissues. Reports have shown the potential role of extracellular vesicles (EVs) and EV cargo as novel and complementary biomarkers in diagnosis and prognosis of PA. In vivo and in vitro studies have identified specific EV surface antigens, EV-proteins, and EV microRNAs that can be useful to develop novel diagnostic algorithms to detect, confirm, or follow up the PA. Moreover, the study of EVs in the field of PA provides further insight in the pathophysiological mechanism of the PA disease.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Circulating microRNAs as Diagnostic Markers in Primary Aldosteronism

Simple Summary

Many patients remain at increased risk of primary aldosteronism (PA) and its consequences due to the difficulty of accurate diagnosis. MicroRNAs circulating in the bloodstream are emerging as biomarkers for disease, particularly specific forms of cancer. In this review article, we argue that they may also have a role in the diagnosis of PA, if observed changes in the microRNA profile of PA tissue are reflected in circulating microRNAs, which can be sampled and analysed readily in a clinical setting. However, for various practical reasons, studies of potential diagnostic circulating microRNAs have often proved difficult to reproduce consistently. We describe these problems and how they might be overcome using, as an example, our design of the circulating microRNA arm of the ongoing ENS@T-HT project, which is intended to confirm whether circulating microRNAs can serve as biomarkers for PA.

Abstract

Primary aldosteronism (PA) is a common and highly treatable condition, usually resulting from adrenocortical tumorous growth or hyperplasia. PA is currently underdiagnosed owing to its complex and protracted diagnostic procedures. A simplified biomarker-based test would be highly valuable in reducing cardiovascular morbidity and mortality. Circulating microRNAs are emerging as potential biomarkers for a number of conditions due to their stability and accessibility. PA is known to alter microRNA expression in adrenocortical tissue; if these changes or their effects are mirrored in the circulating miRNA profile, then this could be exploited by a diagnostic test. However, the reproducibility of studies to identify biomarker-circulating microRNAs has proved difficult for other conditions due to a series of technical challenges. Therefore, any studies seeking to definitively identify circulating microRNA biomarkers of PA must address this in their design. To this end, we are currently conducting the circulating microRNA arm of the ongoing ENS@T-HT study. In this review article, we present evidence to support the utility of circulating microRNAs as PA biomarkers, describe the practical challenges to this approach and, using ENS@T-HT as an example, discuss how these might be overcome.

Anatomical Variations of the Left Adrenal Vein Encountered During Venous Sampling

PURPOSE

To identify anatomical variations in the left adrenal vein (LAV) and to evaluate the role of preprocedural contrast-enhanced computed tomography (CT) planning.

METHODS

The length of the left adrenal central vein (LACV), the vessel that receives blood from all tributaries of the left adrenal gland, was measured using venograms of patients who had undergone adrenal venous sampling (AVS) for the diagnosis of primary aldosteronism between October 2017 and December 2019. The anatomical variants of the LAV were described and classified. Contrast-enhanced CT was used to evaluate the detection rate of the following: (a) confluence of the left inferior phrenic vein and the LAV and (b) the last tributary flowing into the LAV.

RESULTS

In total, 311 patients (143 men, 168 women; mean age: 49.3 years ± 11.0) were enrolled. Of them, 9 (2.9%) patients had anatomical variants lacking a LACV. In patients with a LACV (n = 302), the venographic LACV length was 9.0 mm ± 3.9 (<1 mm in 9 patients). The detection rate of the confluence of the left inferior phrenic vein and LAV, as determined using contrast-enhanced CT, was high (96.2%), whereas that of the last tributary flowing into the LAV was low (0.8%). In 4 of 18 patients with short or absent LACV, the variant was visualized using contrast-enhanced CT.

CONCLUSIONS

In some patients, the LACV is absent or short, which is an anatomical variation. Understanding venographic anatomical variations can help avoid misleading results resulting from a suboptimal sampling site in AVS. For some subtypes, contrast-enhanced CT may also help in planning the AVS procedure.

Performance of the Aldosterone to Renin Ratio as a Screening Test for Primary Aldosteronism

CONTEXT

The aldosterone to renin ratio (ARR) is the guideline-recommended screening test for primary aldosteronism. However, there are limited data in regard to the diagnostic performance of the ARR.

OBJECTIVE

To evaluate the sensitivity and specificity of the ARR as a screening test for primary aldosteronism.

METHODS

We searched the MEDLINE, Embase, and Cochrane databases until February 2020. Observational studies assessing ARR diagnostic performance as a screening test for primary aldosteronism were selected. To limit verification bias, only studies where dynamic confirmatory testing was implemented as a reference standard regardless of the ARR result were included. Study-level data were extracted and risk of bias and applicability were assessed using the QUADAS-2 tool.

RESULTS

Ten studies, involving a total of 4110 participants, were included. Potential risk of bias related to patient selection was common and present in half of the included studies. The population base, ARR positivity threshold, laboratory assay, and reference standard for confirmatory testing varied substantially between studies. The reported ARR sensitivity and specificity varied widely with sensitivity ranging from 10% to 100% and specificity ranging from 70% to 100%. Notably, 3 of the 10 studies reported an ARR sensitivity of <50%, suggesting a limited ability of the ARR to adequately identify patients with primary aldosteronism.

CONCLUSIONS

ARR performance varied widely based on patient population and diagnostic criteria, especially with respect to sensitivity. Therefore, no single ARR threshold for interpretation could be recommended. Limitations in accuracy and reliability of the ARR must be recognized in order to appropriately inform clinical decision-making.

Primary Aldosteronism: a Continuum from Normotension to Hypertension

PURPOSE OF REVIEW

Primary aldosteronism (PA) is the most common cause of secondary hypertension. Emerging evidence suggests that PA is associated with cardiovascular, metabolic, and renal complications, that likely develop insidiously, due to prolonged inappropriate mineralocorticoid receptor activation. In this review, we discuss the expanding clinical and pathological spectrum of PA.

RECENT FINDINGS

Clinical and molecular studies conducted over the recent years reveal that PA traverses a series of contiguous stages. Pre-clinical, but hormonally overt PA has been identified in patients with normal blood pressure, and such patients harbor an increased risk of developing hypertension. Similarly, genetic and histopathological advancements have exposed a spectrum of PA pathology that corresponds to a continuum that spans from pre-clinical stages to florid PA. PA evolves from pre-hypertensive stages to resistant hypertension, along with serious cardiovascular and renal consequences. Early recognition of PA and targeted therapy will be essential for cardiovascular morbidity and mortality prevention in a large number of patients.

New findings bearing on the prevention, detection and management of high blood pressure

PURPOSE OF REVIEW

Hypertension is the foremost risk factor for cardiovascular disease (CVD) and death. This review highlights recent findings that apply to the prevention, detection, and management of high blood pressure (BP), in the context of the 2017 American College of Cardiology/American Heart Association BP guideline.

RECENT FINDINGS

Several new findings on the association of BP measurement with CVD outcomes are now available. (1) Beginning with a systolic BP (SBP) as low as 90 mm Hg, coronary artery calcium deposition and the risk of incident atherosclerotic CVD (ASCVD) increased in stepwise fashion with increasing SBP levels within the normal range in adults at low risk for ASCVD. (2) Isolated diastolic hypertension was not associated with ASCVD, heart failure, or chronic kidney disease. (3) Nocturnal BP appeared to be better associated with CVD outcomes than office or daytime BP. (4) In a head-to-head comparison, home BP monitoring had higher reliability and predictive value than office or ambulatory BP to detect left ventricular hypertrophy, an intermediate form of hypertension-related target organ damage. In addition, new information indicates that autonomous aldosterone production is present in a substantially larger percentage of adults with hypertension than previously recognized. Finally, intensive BP lowering is associated with a significant reduction in the incidence of mild cognitive impairment, a precursor of dementia.

SUMMARY

Ongoing research has made significant progress in the prevention, detection, and management of high BP, clarifying, amplifying, and/or supporting the 2017 ACC/AHA BP guideline recommendations.

Relationship Between the Aldosterone-to-Renin Ratio and Blood Pressure in Young Adults: A Longitudinal Study

[Figure: see text].

The Effect of Antihypertensive Medications on Testing for Primary Aldosteronism

Primary aldosteronism (PA) is a potentially curable form of secondary hypertension caused by excessive renin-independent aldosterone secretion, leading to increased target organ damage and cardiovascular morbidity and mortality. The diagnosis of PA requires measuring renin and aldosterone to calculate the aldosterone-to-renin ratio, followed by confirmatory tests to demonstrate renin-independent aldosterone secretion and/or PA subtype differentiation. Various antihypertensive drug classes interfere with the renin-angiotensin-aldosterone axis and hence evaluation for PA should ideally be performed off-drugs. This is, however, often precluded by the risks related to suboptimal control of blood pressure and serum potassium level in the evaluation period. In the present review, we summarized the evidence regarding the effect of various antihypertensive drug classes on biochemical testing for PA, and critically appraised the issue whether and which antihypertensive medications should be withdrawn or, conversely, might be continued in patients evaluated for PA. The least interfering drugs are calcium antagonists, alpha-blockers, hydralazine, and possibly moxonidine. If necessary, the testing may also be attempted during treatment with beta-blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers but renin and aldosterone measurements must be interpreted in the context of known effects of these drugs on these parameters. Views are evolving on the feasibility of testing during treatment with mineralocorticoid receptor antagonists, as these drugs are now increasingly considered acceptable in specific patient subsets, particularly in those with severe hypokalemia and/or poor blood pressure control on alternative treatment.

Assessment of Anti-Hypertensive Drug Adherence by Serial Aldosterone-To-Renin Ratio Measurement

Reduced or absent compliance to anti-hypertensive treatment is a major obstacle to the achievement of blood pressure target in patients with arterial hypertension. Current available methods for therapeutic adherence assessment display low accuracy, limited applicability in clinical practice and/or high costs. We designed a prospective study to evaluate the accuracy of serial measurement of ARR to assess the therapeutic compliance to RAAS inhibitors. We prospectively enrolled 80 subjects: 40 patients with arterial hypertension and 40 normotensive controls. The ARR was evaluated at baseline and 2 and 8 week after initiation of a RAAS inhibitor in patients with hypertension, and at baseline and 2 weeks for the control group. Adherence to the prescribed therapy was confirmed by therapeutic drug monitoring. We observed a significant increase of renin levels and reduction of aldosterone levels after RAAS inhibitors initiation, with consequent reduction of ARR. Delta ARR (ΔARR), defined as relative change in ARR before and after treatment initiation, provided high accuracy for determination of therapeutic compliance, with an AUC of 0.900 at 2 weeks and 0.886 at 8 weeks. A cut-off of −48% of ΔARR provided 90% sensitivity and 75% specificity, at 2 and 8 weeks. In conclusion, the measurement of ΔARR is a powerful test, cheap and widely available to accurately identify the non-adherence to RAAS inhibitors treatment. Herein we propose the implementation of ΔARR in clinical practice through a multi-step flow-chart for the management of patients with uncontrolled blood pressure, with identification of those suspected of non-adherence, reserving therapeutic drug monitoring for non-adherence confirmation.