Post-saline infusion test aldosterone levels indicate severity and outcome in primary aldosteronism

Differences in target organ damage between captopril challenge test-defined definitive-positive and borderline-range groups among patients with primary aldosteronism

The new Japanese guidelines for primary aldosteronism introduce a category in the judgment of functional confirmatory tests that is called the "borderline range," which is rare in the other international guidelines. The clinical characteristics of this borderline group are not yet understood. To investigate whether this borderline group has any significant differences in terms of target organ damage, we used data from a Japanese nationwide registry (JPAS-II) of individuals with primary aldosteronism or essential hypertension to compare the borderline group with the definitive-positive group and the negative group. We analyzed the cases of 1785 patients based on their captopril-challenge test results. Since the JPAS-II database contains plasma aldosterone concentration values obtained based on both radioimmunoassay (n = 1555) and chemiluminescent enzyme immunoassay (n = 230) principles, we converted these values to their equivalents as if measured by chemiluminescent enzyme immunoassay and conducted all analyses under the simulated condition. Multicovariate-adjusted models revealed significant prevalance odds ratios for chronic kidney disease (2.01, 95% confidence interval: 1.13 to 3.61), electrocardiographic abnormalities (1.66, 95% confidence interval: 1.16 to 2.37). No significant difference was observed between the borderline and negative groups in these assessments (odds ratio [95% confidence interval] for chronic kidney disease: 0.73 [0.26 to 2.02] and electrocardiographic abnormalities: 1.01 [0.60 to 1.70]). We confirmed that the prevalence of target organ damage increases linearly as the aldosterone-to-renin ratio rises following the captopril challenge test. These results provide material to consider regarding the significance of the provisionally established borderline group.

Analysis of clinical and biochemical characteristics and left ventricular hypertrophy in patients with indeterminate saline infusion test results

Introduction

The clinical biochemical characteristics and target organ damage (TOD) in patients with plasma aldosterone concentrations (PAC) ranging from 50 to 100 ng/L after a saline infusion test (SIT) have not been fully studied.

Methods

A total of 611 hypertensive patients with an elevated aldosterone-to-renin ratio (ARR) who underwent a supine SIT at Henan Provincial People's Hospital were enrolled. The patients were divided into three groups according to their post-SIT PAC: <50 ng/L (control group), 50-100 ng/L (indeterminate post-SIT results group), and >100 ng/L (PA group). The clinical and biochemical characteristics and TOD of the three groups were compared. The correlation of the post-SIT PAC with left ventricular mass index (LVMI) was assessed via regression analysis.

Results

The indeterminate post-SIT results group had the youngest patients and the shortest duration of hypertension. The prevalence of renal impairment (RI) and left ventricular hypertrophy (LVH) was lower than that in the PA group (P<0.05), but there was no statistically significant difference from the control group (P>0.05). After adjustment for confounders, the risk of developing carotid plaque was greater in the indeterminate post-SIT results group than in the control group (OR 1.73, 95% CI: 1.11, 2.69), and the prevalence of RI and LVH tended to increase with increasing post-SIT PAC levels. In multiple regression analyses, LVMI was significantly correlated with post-SIT PAC (P<0.05), but the basal PAC, plasma renin activity, and ARR did not significantly correlate with LVMI (P>0.05).

Conclusion

A post-SIT PAC of 50-100 ng/L may be indicative of an early form of PA, and it may serve as an independent predictor of LVH, which could be related to the level of autonomously secreted aldosterone.

Diagnosis and management of primary hyperaldosteronism in patients with hypertension: a practical approach endorsed by the British and Irish Hypertension Society

Alongside the lack of homogeneity among international guidelines and consensus documents on primary hyperaldosteronism, the National UK guidelines on hypertension do not provide extensive recommendations regarding the diagnosis and management of this condition. Local guidelines vary from area to area, and this is reflected in the current clinical practice in the UK. In an attempt to provide support to the clinicians involved in the screening of subjects with hypertension and clinical management of suspected cases of primary hyperaldosteronism the following document has been prepared on the behalf of the BIHS Guidelines and Information Service Standing Committee. Through remote video conferences, the authors of this document reviewed an initial draft which was then circulated among the BIHS Executive members for feedback. A survey among members of the BIHS was carried out in 2022 to assess screening strategies and clinical management of primary hyperaldosteronism in the different regions of the UK. Feedback and results of the survey were then discussed and incorporated in the final document which was approved by the panel after consensus was achieved considering critical review of existing literature and expert opinions. Grading of recommendations was not performed in light of the limited available data from properly designed randomized controlled trials.

Validation of Existing Clinical Prediction Tools for Primary Aldosteronism Subtyping

The new clinical prediction score (SCORE) has been recently proposed for primary aldosteronism (PA) subtyping prior to adrenal vein sampling (AVS). This study aimed to compare that SCORE with previously published scores and their validation using a cohort of patients at our center who had had positive SIT confirming PA and had been diagnosed with either bilateral PA according to AVS or unilateral PA if biochemically cured after an adrenalectomy. Final diagnoses were used to evaluate the diagnostic performance of the proposed clinical prediction tools. Only Kamemura's model (with a maximum score of 4 points) and Kobayashi's score (with a maximum score of 12 points) reached 100% reliability for prediction of bilateral PA; however, with sensitivity of only 3%. On the other hand, the values of SCORE = 3 (with sensitivity of 48%), the SPACE score ≥18 (with sensitivity of 35%), the Kobayashi's score ≤2 (with sensitivity of 28%), and the Kocjan's score = 3 (with sensitivity of 28%) were able to predict unilateral PA with 100% probability. Furthermore, Umakoshi's and Young's models both reached 100% reliability for a unilateral PA with score = 4 and both predictive factors together respectively; however, the sensitivity was lower compared with previous models; 4% and 14%, respectively. None of the clinical prediction tools applied to our cohort predicted unilateral and bilateral subtypes together with the expected high diagnostic performance, and therefore can only be used for precisely defined cases.

Are We Only Detecting the Tip of the Iceberg? A Nationwide Study on Primary Aldosteronism with up to 8-Year Follow-up

BACKGROUND

Long-term follow-up studies on primary aldosteronism (PA) are lacking.

OBJECTIVE

We aim to review results of diagnostic procedures and histopathology for patients diagnosed during 2012-2016 in Iceland, compare unilateral (UD) and bilateral disease (BD) and assess treatment response.

METHODS

Thirty-two patients aged 28-88 were diagnosed and treated according to guidelines.

RESULTS

The majority had BD. Everyone needed potassium supplementation at case detection. We saw a reduction in systolic blood pressure (p < .001, both groups), antihypertensive agents (p = .002 UD and p = .04 BD) and potassium supplementation (p < .001, both groups).

CONCLUSION

Similar treatment response was seen in both subgroups. Ratio of hypokalemia and number of cases indicates severe PA underdiagnosis in Iceland.

Assessment of performance of stratum-specific likelihood ratios of the aldosteronoma resolution score for predicting hypertension cure after adrenalectomy for primary aldosteronism: a systematic review and meta-analysis

The Aldosteronoma Resolution Score (ARS) is the most studied scoring system for predicting the high likelihood of hypertension cure after adrenalectomy for unilateral primary aldosteronism (PA). However, the ARS's accuracy in PA patients worldwide is uncertain. We aimed to perform a meta-analysis of the accuracy, discrimination, and calibration of the ARS using stratum-specific likelihood ratios (SSLR) by organizing available data from cohort studies. We searched PubMed, Embase (Ovid), the Cochrane CENTRAL, Web of Science to November 2021 according to PRISMA statement. The quality assessment used adapted TRIPOD and PROBAST criteria. Thirteen studies comprising 2158 PA patients from North America (43%), Europe (32%), Asia (22%), and other continents, were included. The pooled estimate of the area under the receiver operating characteristic curve for all studies was 0.77 (95% CI: 0.73-0.81), and the ratio of the observed to expected complete resolution of hypertension (CRH) for all studies was 0.9 (95% CI: 0.8-1.0). The summary estimates of the SSLR for all studies were 0.31, 0.89, and 3.1, for the low (ARS 0-1), medium (ARS 2-3), and high-likelihood group (ARS 4-5) of CRH, respectively. However, substantial heterogeneity existed among studies. Follow-up period, and adrenalectomy AVS (adrenal vein sampling)-guided served as potential sources of heterogeneity for quantitative studies, which were measurement and reference standard for qualitative studies selection. In conclusion, in patients with unilateral PA, the ARS is currently an accurate prediction tool, the easiest and cheapest, for identifying long-term high likelihood of CRH after adrenalectomy, particularly when the adrenalectomy is AVS-guided.

Adrenal Venous Sampling Could Be Omitted before Surgery in Patients with Conn’s Adenoma Confirmed by Computed Tomography and Higher Normal Aldosterone Concentration after Saline Infusion Test

Purpose: Adrenal venous sampling (AVS) performed to distinguish unilateral and bilateral primary aldosteronism (PA) is invasive and poorly standardized. This study aimed to identify non-invasive characteristics that can select the patients with unilateral PA who could bypass AVS before surgery. Methods: A single-center study collected a total of 450 patients with PA. Development and validation cohorts included 242 and 208 patients. The AVS was successful in 150 and 138 patients from the cohorts, and the unilateral PA was found in 96 and 94 patients, respectively. Clinical factors independently associated with lateralized AVS in multivariable logistic regression were used to construct a unilateral PA prediction score (SCORE). Results: The proposed SCORE was calculated as a sum of the prevalence of adrenal nodule on computed tomography (2 points) and plasma/serum aldosterone concentration ≥ 165 ng/L after the saline infusion test (SIT) (1 point). Importantly, the SCORE = 3 points identified 48% of unilateral PA patients with a specificity of 100% in the development cohort. The zero rate of false-positive classifications was preserved with the same cut-off value in the validation cohort. Conclusions: AVS could be omitted before surgery in patients with typical Conn´s adenoma provided the aldosterone concentration ≥ 165 ng/L after the SIT.

Validation of three novel clinical prediction tools for primary aldosteronism subtyping

The 20-point clinical prediction SPACE score, the aldosterone-to-lowest potassium ratio (APR), aldosterone concentration (AC) and the AC relative reduction rate after saline infusion test (SIT) have recently been proposed for primary aldosteronism (PA) subtyping prior to adrenal vein sampling (AVS). To validate those claims, we performed a retrospective cross-sectional study that included all patients at our center who had positive SIT to confirm PA and were diagnosed with either bilateral disease (BPA) according to AVS or with lateralized disease (LPA) if biochemically cured after adrenalectomy from November 2004 to the end of 2019. Final diagnoses were used to evaluate the diagnostic performance of proposed clinical prediction tools. Our cohort included 144 patients (40 females), aged 32-72 years (mean 54 years); 59 with LPA and 85 with BPA. The originally suggested SPACE score ≤8 and SPACE score >16 rules yielded about 80% positive predictive value (PPV) for BPA and LPA, respectively. Multivariate analyses with the predictors constituting the SPACE score highlighted post-SIT AC as the most important predictor of PA subtype for our cohort. APR-based tool of <5 for BPA and >15 for LPA yielded about 75% PPV for LPA and BPA. The proposed post-SIT AC <8.79 ng/dL criterion yielded 41% sensitivity and 90% specificity, while the relative post-SIT AC reduction rate of >33.8% criterion yielded 80% sensitivity and 51% specificity for BPA prediction. The application of any of the validated clinical prediction tools to our cohort did not predict the PA subtype with the high diagnostic performance originally reported.

Urinary sodium potassium ratio is associated with clinical success after adrenalectomy in patients with unilateral primary aldosteronism

Background

The urinary sodium potassium (NaK) ratio is associated with dietary sodium and potassium intake and blood pressure, and it also reflects the activity of aldosterone. Herein we evaluated the value of the urinary NaK ratio in predicting the surgical outcomes of patients with unilateral primary aldosteronism (uPA).

Methods

This non-concurrent prospective cohort study was conducted from 2011 to 2017 and included 241 uPA patients who had undergone adrenalectomy. Predictors of successful clinical outcomes were analyzed using logistic regression.

Results

Among the 241 uPA patients, 197 (81.7%) achieved clinical complete or partial success. A urinary sodium potassium ratio <3 (odds ratio (OR): 2.5; 95% confidence interval (CI): 1.2-5.4; p = 0.015), body mass index <25 kg/m² (OR: 2.82; 95% CI: 1.31-6.06; p = 0.008), renin <1 ng/mL/h (OR: 2.51; 95% CI: 1.01-6.21; p = 0.047) and mean preoperative blood pressure >115 mmHg (OR: 5.02; 95% CI: 2.10-11.97; p < 0.001) could predict clinical success after adrenalectomy. Furthermore, higher pre-treatment plasma aldosterone (OR: 1.014; 95% CI 1.005-1.024; p = 0.002) or lower serum potassium (OR: 0.523; 95% CI: 0.328-0.836; p = 0.007) were correlated with lower urinary NaK ratio (<3), and log urinary NaK ratio was positively correlated with serum C-reactive protein (β value 2.326; 95% CI 0.029-4.623; p = 0.047).

Conclusions

uPA patients with a lower urinary NaK ratio, due to high plasma aldosterone and low serum potassium concentrations, were more likely to have clinical success after adrenalectomy. uPA patients with a higher urinary NaK ratio were associated with more severe inflammatory status, and possibly more resistant hypertension post-operatively.

Comparison of the shortened and standard saline infusion tests for primary aldosteronism diagnostics

The saline infusion test (SIT) is widely used to confirm PA, but some patients may not tolerate the standard loading volume of 2 L saline over 4 h. The shortened SIT, loading only 1 L saline over 2 h, is suggested to be useful and would be more acceptable if the diagnostic utility of the shortened SIT is comparable to that of the standard SIT. We compared the diagnostic values of the plasma aldosterone concentration after 2 h of 1 L saline loading (2 h PAC) and that after 4 h of 2 L saline loading (4 h PAC) for the prediction of unilateral aldosterone hypersecretion and postoperative outcome. This retrospective, single-center study involved 555 PA-suspected patients who underwent SIT, 153 patients with adrenal vein sampling (AVS) results, and 37 patients with a 1-year postoperative evaluation. To detect the Japanese cutoff of 4 h PAC > 60 pg/mL, a 2-h PAC Youden Index at 66 pg/mL showed 91% sensitivity and 75% specificity. For unilateral aldosterone hypersecretion, the sensitivity and specificity of 2 h PAC were not inferior to those of 4 h PAC by Markov chain Monte Carlo (MCMC) methods. The sensitivity and specificity of 2 h PAC for postoperative reduction of anti-hypertensive drugs were also not inferior to those of 4 h PAC. Although using the 2 h PAC > 66 pg/mL cutoff may increase false positives for PA diagnosis, the shortened SIT, possibly using a cutoff value higher than 66 pg/mL, may be as useful as the standard SIT for selecting PA patients for AVS and to predict postoperative outcomes with reduced burden on patients.

The 2020 Italian Society of Arterial Hypertension (SIIA) practical guidelines for the management of primary aldosteronism

Background and aim

Considering the amount of novel knowledge generated in the last five years, a team of experienced hypertensionlogists was assembled to furnish updated clinical practice guidelines for the management of primary aldosteronism.

Methods

To identify the most relevant studies, the authors utilized a systematic literature review in international databases by applying the PICO strategy, and then they were required to make use of only those meeting predefined quality criteria. For studies of diagnostic tests, only those that fulfilled the Standards for Reporting of Diagnostic Accuracy recommendations were considered.

Results

Each section was jointly prepared by at least two co-authors, who provided Class of Recommendation and Level of Evidence following the American Heart Association methodology. The guidelines were sponsored by the Italian Society of Arterial Hypertension and underwent two rounds of revision, eventually reexamined by an External Committee. They were presented and thoroughly discussed in two face-to-face meetings with all co-authors and then presented on occasion of the 36th Italian Society of Arterial Hypertension meeting in order to gather further feedbacks by all members. The text amended according to these feedbacks was subjected to a further peer review.

Conclusions

After this process, substantial updated information was generated, which could simplify the diagnosis of primary aldosteronism and assist practicing physicians in optimizing treatment and follow-up of patients with one of the most common curable causes of arterial hypertension.

Mild primary aldosteronism (PA) followed by overt PA are possibly the most common forms of low renin hypertension: a single-center retrospective study

Low renin hypertension (LRH) is a common condition in hypertensive patients, and mainly includes primary aldosteronism (PA) and low renin essential hypertension. To investigate the distributions and clinical manifestations of the main LRH forms, we reviewed 1267 hypertensive patients who underwent assessment for plasma renin activity (PRA) and plasma aldosterone concentration (PAC) by standardized protocols in our specialized center. LRH was defined as PRA < 1.0 ng/mL/h. A saline infusion test (SIT) was performed when LRH patients showed positive screening results for PA. The main LRH forms were defined as follows: post-SIT PAC > 10 ng/dL as 'overt PA', post-SIT PAC 5-10 ng/dL as 'mild PA', and post-SIT PAC < 5 ng/dL or negative screening results as 'non-PA'. Overall, 760 patients were defined as LRH, with 160 classified as overt PA, 268 as mild PA, and 332 as non-PA. The total proportion of PA amounted to 56.3% with 21.0% overt PA and 35.3% mild PA. Compared with the mild PA, patients with overt PA had higher systolic and diastolic blood pressures, lower serum potassium, higher urine potassium excretion, more frequent incidence of stage 3 hypertension, hypokalemia, diabetes mellitus, and classical unilateral adenoma on computerized tomography (P < 0.05). PA including overt and mild forms is indeed a major form of LRH. Clinical manifestations in mild PA are less severe than those in overt PA. Nevertheless, mild PA is more prevalent than overt PA in LRH and should be recognized.

Seated saline infusion test in predicting subtype diagnosis of primary aldosteronism

CONTEXT

Although saline infusion test is widely used as a confirmatory test for primary aldosteronism (PA), it is reportedly less sensitive in patients in whom aldosterone is responsive to the upright position by performing it in recumbent position. Based on a single-centre experience, seated saline infusion test (SSIT) has been reported to be highly sensitive and superior to recumbent testing in identifying both unilateral and bilateral forms of PA. However, due to limited participants number, the utility of SSIT needs to be validated in other series.

OBJECTIVE

This study aimed to evaluate the accuracy of SSIT in determining the PA subtypes compared with adrenocorticotropic hormone stimulation test under dexamethasone suppression (Dex-AT).

PATIENTS AND SETTING

Sixty-four patients with PA who underwent both SSIT and Dex-AT were included. Subtype diagnosis of PA was determined by adrenal venous sampling (AVS) (16 unilateral and 48 bilateral forms).

MAIN OUTCOME MEASURE

Plasma aldosterone concentrations (PACs) were measured after SSIT and Dex-AT.

RESULTS

The area under the receiver operating characteristic (ROC) curve for diagnosing unilateral PA was greater in SSIT than that in Dex-AT (0.907 vs. 0.755; P = .023). ROC curve analysis predicted optimal cut-off PACs of 13.1 ng/dL (sensitivity, 93.8%; specificity, 79.2%) for SSIT and 34.2 ng/dL (sensitivity, 75.0%; specificity, 68.8%) for Dex-AT.

CONCLUSIONS

Seated saline infusion test has superior accuracy in subtype diagnosis of PA compared with Dex-AT. SSIT can be a sensitive test for determining patients who require AVS prior to surgery.

Plasma Aldosterone After Seated Saline Infusion Test Outperforms Captopril Test at Predicting Clinical Outcomes After Adrenalectomy for Primary Aldosteronism

OBJECTIVE

The saline infusion test (SIT) and the captopril test (CT) are widely used as confirmatory tests for primary aldosteronism (PA). We hypothesized that post-SIT and post-CT plasma aldosterone concentrations (PAC) indicate the severity of aldosterone-producing adenoma (APA) and might predict clinical outcome.

METHODS

We recruited 216 patients with APA in the Taiwan Primary Aldosteronism Investigation (TAIPAI) registry who received both seated SIT and CT as confirmatory tests. The data of 143 patients who underwent adrenalectomy with complete follow-up after diagnosis were included in the final analysis. We determined the proportion of patients achieving clinical success in accordance with the Primary Aldosteronism Surgical Outcome consensus. Logistic regression analysis was conducted to identify preoperative factors associated with cure of hypertension.

RESULTS

Complete clinical success was achieved in 48 (33.6%) patients and partial clinical success in 59 (41.2%) patients; absent clinical success was seen in 36 (25.2%) of 143 patients. Post-SIT PAC but not post-CT PAC was independently associated with clinical outcome. Higher levels of post-SIT PAC had a higher likelihood of clinical benefit (complete plus partial clinical success; odds ratio = 1.04 per ng/dl increase, 95% confidence interval = 1.01, 1.06; P = 0.004). Patients with post-SIT PAC > 25 ng/dl were more likely to have a favorable clinical outcome after adrenalectomy. This cutoff value translated into a positive predictive value of 86.0%.

CONCLUSIONS

We suggest that post-SIT PAC is a better predictor than post-CT PAC for clinical success in PA post adrenalectomy.

Downregulated Serum 14, 15-Epoxyeicosatrienoic Acid Is Associated With Abdominal Aortic Calcification in Patients With Primary Aldosteronism

Patients with primary aldosteronism (PA) have increased risk of target-organ damage, among which vascular calcification is an important indicator of cardiovascular mortality. 14, 15-Epoxyeicosatrienoic acid (14, 15-EET) has been shown to have beneficial effects in vascular remodeling. However, whether 14, 15-EET associates with vascular calcification in PA is unknown. Thus, we aimed to investigate the association between 14, 15-EET and abdominal aortic calcification (AAC) in patients with PA. Sixty-nine patients with PA and 69 controls with essential hypertension, matched for age, sex, and blood pressure, were studied. 14, 15-Dihydroxyeicosatrienoic acid (14, 15-DHET), the inactive metabolite from 14, 15-EET, was estimated to reflect serum 14, 15-EET levels. AAC was assessed by computed tomographic scanning. Compared with matched controls, the AAC prevalence was almost 1-fold higher in patients with PA (27 [39.1%] versus 14 [20.3%]; P=0.023), accompanied by significantly higher serum 14, 15-DHET levels (7.18±4.98 versus 3.50±2.07 ng/mL; P<0.001). Plasma aldosterone concentration was positively associated with 14, 15-DHET (β=0.444; P<0.001). Multivariable logistic analysis revealed that lower 14, 15-DHET was an independent risk factor for AAC in PA (odds ratio, 1.371; 95% confidence interval, 1.145-1.640; P<0.001), especially in young patients with mild hypertension and normal body mass index. In conclusion, PA patients exibited more severe AAC, accompanied by higher serum 14, 15-DHET levels. On the contrary, decreased 14, 15-EET was significantly associated with AAC prevalence in PA patients, especially in those at low cardiovascular risk.

Saline Infusion Test highly associated with the incidence of cardio- and cerebrovascular events in primary aldosteronism

Primary aldosteronism (PA) is caused by excess secretion of aldosterone and is an independent risk factor for cardio-cerebro-vascular (CCV) events. The goal of treatment of PA should include prevention of CCV events. A definitive diagnosis of PA is established by confirmatory tests [saline infusion test (SIT), furosemide upright test (FUT) and captopril challenge test (CCT)]. However, there is no information on whether the hormone levels measured by these confirmatory tests are associated with CCV events. The aim of this retrospective study was to elucidate the relationship between the results of the above confirmatory tests and prevalence of CCV disease in patients with PA. The study subjects were 292 PA patients who were assessed for past history of CCV events at the time of diagnosis of PA. CCV events were significantly higher in patients with positive than negative SIT (12.8% vs. 3.3%, p=0.04). There were no differences in the incidences of CCV events between patients with positive and negative CCT and FUT (CCT: 11.0% vs. 3.9%, p=0.13, FUT: 6.1% vs. 5.7%, p=0.93). Our results demonstrated a higher incidence of CCV disease in PA SIT-positive patients compared to those with negative test. SIT is a potentially useful test not only for the diagnosis of PA but also assessment of the risk of CCV events.

Suppression of Aldosterone Secretion After Recumbent Saline Infusion Does Not Exclude Lateralized Primary Aldosteronism

Guidelines recommend suppression tests such as the saline infusion test (SIT) to ascertain the diagnosis of primary aldosteronism (PA) in patients with a high aldosterone:renin ratio. However, suppression tests have only been evaluated in small retrospective series, and some experts consider that they are not helpful for the diagnosis of PA. In this study, we evaluated whether low post-SIT aldosterone concentrations do exclude lateralized PA. Between February 2009 and December 2013, 199 patients diagnosed with PA on the basis of 2 elevated aldosterone:renin ratio results and a high basal plasma or urinary aldosterone level or high post-SIT aldosterone level had a selective adrenal venous sampling. We used a selectivity index of 2 and a lateralization index of 4 to interpret the adrenal venous sampling results. Baseline characteristics of the patients were the following (percent or median): men 63%, 48 years old, office blood pressure 142/88 mm Hg, serum potassium 3.4 mmol/L, aldosterone:renin ratio 113 pmol/mU, plasma aldosterone concentration 588 pmol/L. The proportion of patients with lateralized adrenal venous sampling was 12 of 41 (29%) among those with post-SIT aldosterone <139 pmol/L (5 ng/dL) and 38 of 104 (37%) among those with post-SIT aldosterone <277 pmol/L (10 ng/dL). Post-SIT aldosterone levels were not associated with the blood pressure outcome of adrenalectomy. A low post-SIT aldosterone level cannot rule out lateralized PA, even with a low threshold (139 pmol/L). Adrenal venous sampling should be considered for patients who are eligible for surgery with elevated basal aldosterone levels even if they have low aldosterone concentrations after recumbent saline suppression testing.

Clinical validation for the aldosterone-to-renin ratio and aldosterone suppression testing using simultaneous fully automated chemiluminescence immunoassays

BACKGROUND

As larger numbers of hypertensive patients are screened for primary aldosteronism with the aldosterone-to-renin ratio (ARR), automated analyzers present a practical solution for many laboratories. We report the method-specific ARR cutoff determined with direct, automated chemiluminescence immunoassays allowing the simultaneous measurement of plasma aldosterone concentrations (PACs) and plasma renin concentrations (PRCs).

METHODS

Method comparisons to commonly employed assays and tandem mass spectrometry were undertaken. Patients were previously diagnosed based on the local ARR cutoff of 1.2 (ng/dl)/(μIU/ml) in samples collected in upright seated position. Lack of aldosterone suppression in response to salt load to less than 5 ng/dl confirmed primary aldosteronism. For the new assays, the optimal ARR cutoff was established in 152 patients with essential hypertension, 93 with primary aldosteronism and 147 normotensive patients. Aldosterone suppression was assessed in 73 essential hypertensive and 46 primary aldosteronism patients.

RESULTS

PAC and PRC were significantly correlated to values determined with currently available methods (P < 0.001). In patients with primary aldosteronism, patients with essential hypertension and controls, mean (95% confidence interval) PAC was 28.4 (25.4-31.8), 6.4 (5.9-6.9) and 6.2 (5.6-6.9) ng/dl, respectively. In the same groups, PRC was 6.6 (5.6-7.7), 12.9 (11.2-14.8) and 26.5 (22.2-31.5) μIU/ml. An ARR cutoff of 1.12 provided 98.9% sensitivity and 78.9% specificity. Employing the new assay aldosterone suppression confirmed the diagnosis of primary aldosteronism and essential hypertension using the cutoff of 5 ng/dl.

CONCLUSION

Our data demonstrate that the new assays present a convenient alternative for the measurement of PAC and PRC on a single automated analyzer. Availability of these simultaneous assays should facilitate screening and diagnosis of primary aldosteronism.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Glucose Metabolism in Primary Aldosteronism

In recent years, an increasing number of studies have revealed deleterious effects of aldosterone via the mineralocorticoid receptor (MR). Especially in patients with primary aldosteronism (PA) a significant higher estimated risk of developing cardiovascular comorbidities and comortalities compared to essential hypertensives was reported. As diabetes mellitus and the metabolic syndrome are one of the major contributors to cardiovascular morbidity and mortality their connection to aldosterone excess became a focus of research in PA patients. Several studies assessed the effect of PA on glucose metabolism, the prevalence of diabetes mellitus, and the effect of PA treatment on both revealing different results. Therefore, we performed an extensive literature research. This review focuses on the current knowledge of the connection between aldosterone excess, glucose homeostasis, and diabetes mellitus in patients with PA. We have highlighted this topic from a pro and contra perspective followed by a summarizing concluding remark. Additionally, we have briefly reviewed the data on possible underlying mechanisms and indicated future considerations on the possible impact of cortisol co-secretion in PA.