Primary aldosteronism in hypertensive patients: clinical implications and target therapy

Global and regional prevalence and cardiovascular risk of primary aldosteronism: a systematic review and meta-analysis

BACKGROUND

An updated understanding of global prevalence of primary aldosteronism (PA) is essential for the development of primary prevention and management strategies for PA. We aimed to provide update global and regional prevalence of PA and to evaluate cardiovascular risk of PA compared to essential hypertension (EH).

METHODS

We systematically searched PubMed, Web of Science, and Embase for studies on the prevalence of PA or cardiovascular risk of PA published up to July 31, 2022 for this meta-analysis. Global prevalence of PA was calculated using random-effects inverse-variance models and cardiovascular risk of PA was estimated using random-effects models.

RESULTS

We identified 39 articles for meta-analysis of PA prevalence, and 13 articles were included in the meta-analysis of cardiovascular risk. Global prevalence of PA was 9.4% (95% CI: 8.3-10.5), with a higher prevalence in males than in females. Prevalence of PA was higher in the South-East Asia than in other regions, and higher in lower middle-income countries than in other economic levels, with greater country-specific differences. Compared with EH, PA had an increased risk of coronary artery disease (OR=1.88, 95% CI: 1.41-2.50), stroke (OR=2.50, 95% CI: 2.08-3.02), heart failure (OR=2.06, 95% CI: 1.33-3.19), and atrial fibrillation (OR=3.17, 95% CI: 2.09-4.80).

CONCLUSION

The management of the increasing number of patients with PA and its associated burden of cardiovascular disease is likely to place increasing pressure on health systems. Early detection of PA is essential to reduce the associated burden, especially in areas where the assessment of PA has not received sufficient attention.

High Prevalence of Primary Aldosteronism in Patients with Type 2 Diabetes Mellitus and Hypertension

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. The prevalence of hypertension is higher in patients with diabetes mellitus-2 (DM-2). Following the limited existing data, we prospectively investigated the prevalence of aldosterone excess either as autonomous secretion (PA) or as a hyper-response to stress in hypertensive patients with DM-2 (HDM-2). A total of 137 HDM-2 patients and 61 non-diabetics with essential hypertension who served as controls (EH-C) underwent a combined, overnight diagnostic test, the Dexamethasone–captopril–valsartan test (DCVT) used for the diagnosis of PA and an ultralow dose (0.3 μg) ACTH stimulation test to identify an exaggerated aldosterone response to ACTH stimulation. Twenty-three normotensive individuals served as controls (NC) to define the normal response of aldosterone (ALD) and aldosterone-to-renin ratio (ARR) to the ultralow dose ACTH test. Using post-DCVTALD and ARR from the EH-C, and post-ACTH peak ALD and ARR from the NC, 47 (34.3%) HDM-2 patients were found to have PA, whereas 6 (10.4%) HDM-2 patients without PA (DCVT-negative) exhibited an exaggerated aldosterone response to stress—a prevalence much higher than ever reported. Treatment with mineralocorticoid receptor antagonists (MRAs) induced a significant and permanent reduction of BP in all HDM-2 patients. Early diagnosis and targeted treatment of PA is crucial to prevent any aggravating effect on chronic diabetic complications.

Autonomous Aldosterone Secretion as a Subclinical Form of Primary Aldosteronism: Pathogenesis and Clinical Significance

In recent years, a substantial prevalence of primary aldosteronism (PA) has been demonstrated in both normotensive and mildly hypertensive cohorts. Consequently, a classic presentation of the syndrome, i. e. moderate-to-severe and resistant hypertension with concomitant hypokalemia, should be considered a tip-of-the-iceberg phenotype of a wide PA spectrum. Its entire range encompasses the non-classic clinical forms of mild hypertension and prehypertension but also several biochemical presentations, including patients who meet PA screening and confirmation test criteria, as well as those with either of them and those with other parameters indicating mineralocorticoid excess. In the current review, research insights on the pathogenetic background and clinical significance of autonomous aldosterone secretion (AAS) are presented, which is defined as a constellation of either: 1) normotension, normokalemia, a positive PA screening (high aldosterone-to-renin ratio) and/or confirmation test, or 2) hypertension, normokalemia and a positive PA screening but negative confirmation test. For this purpose, a literature search of the PubMed database was conducted. Advances in immunohistochemistry and genetic sequencing of isolated adrenal cells are provided as probable morphologic basis of the wide range of aldosterone secretion autonomy. Also, the role of corticotropin as an aldosterone secretagogue is discussed. To date, clinical studies depict consequences of subclinical PA phenotypes, such as increased mortality and risk of developing hypertension, impaired arterial and kidney function, association with metabolic syndrome and age, as well as osteoporosis.

Prevalence of Primary Aldosteronism Across the Stages of Hypertension Based on a New Combined Overnight Test

Primary aldosteronism (PA) is the most common endocrine cause of arterial hypertension. Despite the increasing incidence of hypertension worldwide, the true prevalence of PA in hypertension was only recently recognized. The objective of the work was to estimate the prevalence of PA in patients at different stages of hypertension based on a newly developed screening-diagnostic overnight test. This is a prospective study with hypertensive patients (n=265) at stage I (n=100), II (n=88), and III (n=77) of hypertension. A group of 103 patients with essential hypertension without PA was used as controls. PA diagnosis was based on a combined screening-diagnostic overnight test, the Dexamethasone-Captopril-Valsartan Test (DCVT) that evaluates aldosterone secretion after pharmaceutical blockade of angiotensin-II and adrenocorticotropic hormone. DCVT was performed in all participants independently of the basal aldosterone to renin ratio (ARR). The calculated upper normal limits for post-DCVT aldosterone levels [3 ng/dl (85 pmol/l)] and post-DCVT ARR [0.32 ng/dl/μU/ml (9 pmol/IU)] from controls, were applied together to establish PA diagnosis. Using these criteria PA was confirmed in 80 of 265 (30%) hypertensives. The prevalence of PA was: 21% (21/100) in stage I, 33% (29/88) in stage II, and 39% (30/77) in stage III. Serum K⁺ levels were negatively correlated and urinary K⁺ was positively correlated in PA patients with post-DCVT ARR (r=-0.349, p <0.01, and r=0.27, p <0.05 respectively). In conclusion, DCVT revealed that PA is a highly prevalent cause of hypertension. DCVT could be employed as a diagnostic tool in all subjects with arterial hypertension of unknown cause.

Surgical treatment outcome of primary aldosteronism assessed using new modified diagnostic tests

PURPOSE

Primary aldosteronism (PA) is the most frequent type of endocrine hypertension. In our previous studies, we introduced two modified diagnostic tests for PA, the post-dexamethasone saline infusion test (DSIT) and the overnight dexamethasone, captopril, and valsartan test (DCVT). In this study, we aimed to validate both tests in respect to the biochemical and clinical response of a cohort of hypertensive patients in pre- and post-surgical setting.

METHODS

We retrospectively studied 41 hypertensive patients (16 males), with a median (IQR, range) age of 50 (16, 35-74) years and positive histology for adrenal adenoma. Preoperatively, all patients had a single adenoma on CT and a diagnosis of PA with either DSIT or DCVT. The defined daily dose (DDD) of hypertensive drugs was assessed pre- and postoperatively. DSIT or DCVT and basal ARR were reassessed postoperatively.

RESULTS

Two of the 41 patients failed to suppress aldosterone post-surgery, leading to a post-adrenalectomy biochemical cure rate of 95%, while blood pressure was improved in 36 patients, leading to a clinical cure rate of 88% as assessed by the DDD methodology.

CONCLUSIONS

The present study was a proof-of-concept process to validate two modified diagnostic tests for PA in clinical practice. These tests, used to diagnose a group of patients with PA, successfully assessed their biochemical cure post-adrenalectomy at rates similar to those reported in the literature.

Five Reasons for the Failure to Diagnose Aldosterone Excess in Hypertension

Primary hyperaldosteronism (PA) is a well-known cause of hypertension although its exact prevalence amongst patients with apparent essential hypertension has been a matter of debate. A number of recent studies have suggested that mild forms of PA may be relatively common taking into consideration factors that were previously either overestimated or ignored when developing diagnostic tests of PA and when applying these tests into normotensive individuals. The performance characteristics and diagnostic accuracy of such tests are substantially increased when the adrenocorticotrophin effect, inappropriate potassium levels and their application in carefully selected normotensive individuals are considered. In the present review, we critically analyze these issues and provide evidence that several, particularly mild, forms of PA can be effectively identified exhibiting potentially important clinical implications.

Salt intake in mineralocorticoid receptor antagonist-treated primary aldosteronism: foe or ally?

Mild hyperkalemia is a common side effect of mineralocorticoid receptor antagonist (MRA) treatment of patients with primary aldosteronism (PA), which can be worsened by instructions to minimize salt intake. Our objective was to evaluate the effect of salt consumption on serum potassium levels and mean, mean minimal, and mean maximal systolic and diastolic blood pressure (BP) in MRA-treated hyperkalemic PA patients under relative salt restriction. Seventeen consecutive mildly hyperkalemic MRA-treated PA patients aged 66.3 ± 8.37 years were recruited. Body mass index (BMI) and BP were assessed, and serum and 24-h urinary sodium and potassium levels, plasma renin, and serum aldosterone were measured, while patients followed a relatively salt-restricted diet, after 1 month of controlled salt supplementation (usual salt-restricted diet plus 4 g salt/day) and after 6 months on instructions for free dietary salt consumption. Baseline salt consumption was additionally evaluated in two more patient groups (normotensive subjects and normokalemic MRA-treated PA patients). One month of controlled salt supplementation (24-h urine sodium (median, min, max): 195.2 (120.30-275.20) vs 110.13 (34.30-139.20) mEq/day, p < 0.001) resulted in increased kaliuresis (62.25 (40.69-97.0) vs 54.0 (23.28-79.60) mEq/day, p = 0.001) and a decrease of serum potassium (5.2 (5-5.70) vs 4.6 (3.8-5.1) mEq/L, p < 0.001), while serum sodium (139 (133-141) vs 1 39 (135-144) mEq/L) and mean systolic (130 (105-141 vs. 130 (106-141) mmHg) and diastolic (76 (53-85) vs75 (53-84) mmHg) BP remained stable. These findings were unchanged after 6 months of free salt consumption. BMI remained constant, while plasma renin and serum aldosterone decreased following salt repletion. Adequate salt consumption attenuates MRA-induced hyperkalemia in relatively salt-restricted PA patients without affecting BP or BMI.

CaF2 nanoparticles as peroxidase mimics for rapid and sensitive detection of aldosterone

In this work, CaF₂ nanoparticles were successfully synthesized by a simple direct precipitation method and firstly used as a peroxidase mimics for rapid and high sensitive colorimetric detection of aldosterone. The CaF₂ nanoparticles were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). The CaF₂ nanoparticles can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue product oxidized TMB (oxTMB) in the presence of H₂O₂ and this peroxidase-like activity of CaF₂ is found out to follow Michaelis-Menten kinetics. Experiments showed that the catalytic mechanism of CaF₂ nanoparticles was attributed to that it could result in the decomposition of H₂O₂ to produce hydroxyl radicals (•OH). The absorbance change value of the reaction system was linear with the aldosterone concentration in the range of 2.0-40.0 nM, and the detection limit was 0.6 nM. Moreover, the developed method was applied to detect aldosterone in human serum samples. It provides a new platform for enzyme functional simulation and analytical sensing research.

Loss of secretin results in systemic and pulmonary hypertension with cardiopulmonary pathologies in mice

More than 1 billion people globally are suffering from hypertension, which is a long-term incurable medical condition that can further lead to dangerous complications and death if left untreated. In earlier studies, the brain-gut peptide secretin (SCT) was found to be able to control blood pressure by its cardiovascular and pulmonary effects. For example, serum SCT in patients with congestive heart failure was one-third of the normal level. These observations strongly suggest that SCT has a causal role in blood pressure control, and in this report, we used constitutive SCT knockout (SCT^−/−) mice and control C57BL/6N mice to investigate differences in the morphology, function, underlying mechanisms and response to SCT treatment. We found that SCT^−/− mice suffer from systemic and pulmonary hypertension with increased fibrosis in the lungs and heart. Small airway remodelling and pulmonary inflammation were also found in SCT^−/− mice. Serum NO and VEGF levels were reduced and plasma aldosterone levels were increased in SCT^−/− mice. Elevated cardiac aldosterone and decreased VEGF in the lungs were observed in the SCT^−/− mice. More interestingly, SCT replacement in SCT^−/− mice could prevent the development of heart and lung pathologies compared to the untreated group. Taken together, we comprehensively demonstrated the critical role of SCT in the cardiovascular and pulmonary systems and provide new insight into the potential role of SCT in the pathological development of cardiopulmonary and cardiovascular diseases.

Case detection in primary aldosteronism: high-diagnostic value of the aldosterone-to-renin ratio when performed under standardized conditions

OBJECTIVE

The aldosterone-to-renin ratio is widely used and is the recommended screening modality for primary aldosteronism by the Endocrine Society Guideline. However, studies on its diagnostic accuracy have been inconsistent, which is mainly because of methodological limitations. We set out to evaluate this diagnostic value by using a highly standardized study protocol, which is in line with the Endocrine Society Guideline recommendations regarding indications for screening, testing conditions and reference standards in daily clinical practice.

METHODS

In this prospective study, 233 consecutive patients referred to the University Medical Center Utrecht with difficult-to-control hypertension were enrolled. In addition to aldosterone-to-renin ratio measurements, all patients underwent a saline infusion test as a reference standard. A plasma aldosterone concentration greater than 280 pmol/l after saline infusion was considered diagnostic for aldosteronism and the plasma renin activity was assessed to exclude patients with secondary aldosteronism from the final primary aldosteronism diagnosis.

RESULTS

Correlation of the aldosterone-to-renin ratio (cut-off >5) with primary aldosteronism diagnosis showed 16 true positive, 29 false positive, 188 true negative and 0 false negative aldosterone-to-renin ratios, resulting in a sensitivity of 100% (CI 75.9-100), specificity of 86.7% (CI 81.2-90.7), positive-predictive value of 35.6% (CI 22.3-51.3) and negative-predictive value of 100% (CI 97.5-100.0). The corresponding area under the curve was 0.933 (CI 0.900-0.966).

CONCLUSION

These findings show that the aldosterone-to-renin ratio is a good screening modality for primary aldosteronism and is without a high risk of missing a primary aldosteronism diagnosis whenever performed under well standardized conditions.

Renal Innervation in Resistant Hypertension: A Review of Pathophysiology and Renal Denervation as Potential Treatment

Background

Advances in treatment and increased awareness have improved the prognosis for many patients with hypertension (HTN). Resistant hypertension (RH) refers to a subset of hypertensive individuals who fail to achieve a desired blood pressure (BP) despite concurrent use of 3 different classes antihypertensive agents, one being a diuretic, and proper lifestyle changes. The prevalence and prognosis of RH are unclear owing to its heterogeneous etiologies, risk factors, and secondary comorbidities. Previous research has provided evidence that increased renal sympathetic nerve activity (RSNA) within the renal artery contributes to RH development. Renal denervation (RDN) is a procedure that attempts to ameliorate the effects of heightened RSNA via ablation renal sympathetic fibers. BP reductions associated with RDN may be attributed to decreased norepinephrine spillover, restoration of natriuresis, increasing renal blood flow, and lowering plasma renin activity. Early clinical trials perpetuated positive results, and enthusiasm grew exponentially. However, recent clinical trials have called into question RDN's efficacy. Numerous limitations must be addressed to discern the true effectiveness of RDN as a therapeutic option for RH.

Objective

We aimed to review the current understanding of RH, the anatomy of renal arteries, physiology of RH on renal arteries, anatomical pathways of the sympathetic involved in RH, RDN as a treatment option, and all relevant clinical trials treating RH with RDN.

Methods

We piloted a MEDLINE^® database search of literature extending from 1980 to 2017, with emphasis on the previous five years, combining keywords such as “resistant hypertension” and 
“renal denervation.”

Conclusion

A plethora of information is available regarding heightened RSNA leading to RH. RDN as a possible treatment option has shown a range of results. Reconciling RDN's true efficacy requires future trials to increased sites of nerve ablation, standardized protocol, increased anatomical understanding per individual basis, stricter guidelines regarding study design, increased operator experience, and integrating the use of a multielectrode catheter.

A new highly sensitive and specific overnight combined screening and diagnostic test for primary aldosteronism

CONTEXT

Primary aldosteronism (PA) is the most common cause of endocrine hypertension that is diagnosed following a two-step process: an initial screening test, based on the serum aldosterone-to-renin ratio (ARR), followed by a relatively laborious and time-consuming confirmatory test to document autonomous aldosterone (ALD) secretion.

OBJECTIVE

The aim of this study is to develop a simple overnight test for the early and definite diagnosis of PA.

PATIENTS AND METHODS

Totally, 148 hypertensive patients underwent a fludrocortisone-dexamethasone suppression test (FDST) and the new overnight diagnostic test (DCVT) using pharmaceutical RAAS (renin-angiotensin-aldosterone system) blockade with dexamethasone, captopril and valsartan.

RESULTS

Of the 148 patients, 45 were diagnosed as having PA and they all normalized their elevated blood pressure (BP) after administration of spironolactone or eplerenone. The remaining 103 patients were considered as having essential hypertension and served as controls. Using ROC analysis, the estimated sensitivity and specificity were 91 and 100%, respectively, for the post-FDST ARR, whereas 98% and 89% and 100% and 82% for the post-DCVT ARR and post-DCVT ALD, respectively, with selected cutoffs of 0.32ng/dL/μU/mL and 3ng/dL respectively. However, considering these cutoffs simultaneously, the estimated sensitivity and specificity were 98 and 100% respectively. Applying these cutoffs, the diagnosis of PA was confirmed in 44 (98%) of the 45 patients who were considered to have the disease.

CONCLUSIONS

In this study, a highly sensitive and specific, low-cost, rapid, safe, and easy-to-perform diagnostic test (DCVT) for PA is described, which could be utilized on an outpatient basis potentially substituting conventional laborious testing.

Cellular Pathophysiology of an Adrenal Adenoma-Associated Mutant of the Plasma Membrane Ca(2+)-ATPase ATP2B3

Adrenal aldosterone-producing adenomas (APAs) are a main cause for primary aldosteronism leading to arterial hypertension. Physiologically, aldosterone production in the adrenal gland is stimulated by angiotensin II and high extracellular potassium. These stimuli lead to a depolarization of the plasma membrane and, as a consequence, an increase of intracellular Ca(2+). Mutations of the plasma membrane Ca(2+)-ATPase ATP2B3 have been found in APAs with a prevalence of 0.6%-3.1%. Here, we investigated the effects of the APA-associated ATP2B3(Leu425_Val426del) mutation in adrenocortical NCI-H295R and human embryonic kidney (HEK-293) cells. Ca(2+) measurements revealed a higher basal Ca(2+) level in cells expressing the mutant ATP2B3. This rise in intracellular Ca(2+) was even more pronounced under conditions with high extracellular Ca(2+) pointing to an increased Ca(2+) influx associated with the mutated protein. Furthermore, cells with the mutant ATP2B3 appeared to have a reduced capacity to export Ca(2+) suggesting a loss of the physiological pump function. Surprisingly, expression of the mutant ATP2B3 caused a Na(+)-dependent inward current that strongly depolarized the plasma membrane and compromised the cytosolic cation composition. In parallel to these findings, mRNA expression of the cytochrome P450, family 11, subfamily B, polypeptide 2 (aldosterone synthase) was substantially increased and aldosterone production was enhanced in cells overexpressing mutant ATP2B3. In summary, the APA-associated ATP2B3(Leu425_Val426del) mutant promotes aldosterone production by at least 2 different mechanisms: 1) a reduced Ca(2+) export due to the loss of the physiological pump function; and 2) an increased Ca(2+) influx due to opening of depolarization-activated Ca(2+) channels as well as a possible Ca(2+) leak through the mutated pump.

The Potential of ACTH in the Genesis of Primary Aldosteronism

Aldosterone is a homeostatic hormone, rising in volume depletion, sodium deficiency, and potassium loading, in response to angiotensin11 and elevation of plasma potassium. Pathophysiologically, in primary aldosteronism (PA) aldosterone levels are inappropriate for the patient's sodium and potassium status, and thus outside the normal feedback loop. ACTH is equivalent with A11 and [K(+)] in elevating aldosterone: its effects differ from those of the other secretagogues in four ways. First, it is not sustained; second, it raises aldosterone and cortisol secretion with equal potency; third, it is outside the normal feedback loops, reflecting the epithelial action of aldosterone; and finally its possible role in driving inappropriate aldosterone secretion (aka PA) is not widely recognized. Thirty years ago, it was shown that on a fixed sodium intake of 175 meq/day 36 of 100 unselected hypertensives, in whom PA has been excluded on contemporary criteria, had 24 h urinary aldosterone levels above the upper limit of normotensive controls. More recently, the dexamethasone enhanced fludrocortisone suppression test (FDST) showed 29% of unselected hypertensives to have plasma aldosterone concentrations above the upper limit of normotensive controls. In subjects negative for PA on the FDST, 27% were extremely hyper-responsive to ultra-low dose ACTH infusion; the remaining 73% showed minimal aldosterone elevation, as did normotensive controls: all three groups had negligible cortisol responses. On treadmill testing, no differences were found between groups in (minimally altered) ACTH and cortisol levels: hyper-responders to ultra-low ACTH, however, showed a major elevation in PAC. The implications of these studies, when validated, are substantial for PA, in that approximately half of hypertensive patients appear to show inappropriate aldosterone levels for their sodium status. The physiological role(s) of ACTH as an acute aldosterone secretagogue, and the mechanisms whereby its continuous secretion is curtailed, remain to be established.

Role of ACTH and Other Hormones in the Regulation of Aldosterone Production in Primary Aldosteronism

The major physiological regulators of aldosterone production from the adrenal zona glomerulosa are potassium and angiotensin II; other acute regulators include adrenocorticotropic hormone (ACTH) and serotonin. Their interactions with G-protein coupled hormone receptors activate cAMP/PKA pathway thereby regulating intracellular calcium flux and CYP11B2 transcription, which is the specific steroidogenic enzyme of aldosterone synthesis. In primary aldosteronism (PA), the increased production of aldosterone and resultant relative hypervolemia inhibits the renin and angiotensin system; aldosterone secretion is mostly independent from the suppressed renin-angiotensin system, but is not autonomous, as it is regulated by a diversity of other ligands of various eutopic or ectopic receptors, in addition to activation of calcium flux resulting from mutations of various ion channels. Among the abnormalities in various hormone receptors, an overexpression of the melanocortin type 2 receptor (MC2R) could be responsible for aldosterone hypersecretion in aldosteronomas. An exaggerated increase in plasma aldosterone concentration (PAC) is found in patients with PA secondary either to unilateral aldosteronomas or bilateral adrenal hyperplasia (BAH) following acute ACTH administration compared to normal individuals. A diurnal increase in PAC in early morning and its suppression by dexamethasone confirms the increased role of endogenous ACTH as an important aldosterone secretagogue in PA. Screening using a combination of dexamethasone and fludrocortisone test reveals a higher prevalence of PA in hypertensive populations compared to the aldosterone to renin ratio. The variable level of MC2R overexpression in each aldosteronomas or in the adjacent zona glomerulosa hyperplasia may explain the inconsistent results of adrenal vein sampling between basal levels and post ACTH administration in the determination of source of aldosterone excess. In the rare cases of glucocorticoid remediable aldosteronism, a chimeric CYP11B2 becomes regulated by ACTH activating its chimeric CYP11B1 promoter of aldosterone synthase in bilateral adrenal fasciculate-like hyperplasia. This review will focus on the role of ACTH on excess aldosterone secretion in PA with particular focus on the aberrant expression of MC2R in comparison with other aberrant ligands and their GPCRs in this frequent pathology.

Stress-induced Aldosterone Hyper-Secretion in a Substantial Subset of Patients With Essential Hypertension

CONTEXT

Aldosterone (ALD) secretion is regulated mainly by angiotensin II, K(+), and adrenocorticotropic hormone (ACTH). Mineralocorticoid receptor antagonists (MRAs) have effectively been used for the treatment of patients with hypertension who do not have primary aldosteronism (PA).

OBJECTIVE

We tested whether chronic stress-related ACTH-mediated ALD hypersecretion and/or zona glomerulosa hypersensitivity could be implicated in the pathogenesis of essential hypertension (ESHT).

PATIENTS AND METHODS

One hundred thirteen hypertensives without PA and 61 normotensive controls underwent an ultralow-dose (0.03-μg) ACTH stimulation and a treadmill test. Patients with ALD hyper-response according to the cutoffs obtained from controls received treatment with MRAs and underwent genomic DNA testing for the presence of the CYP11B1/CYP11B2 chimeric gene and KCNJ5 gene mutations. A control group of 22 patients with simple ESHT received treatment with MRAs.

RESULTS

Based on the cutoffs of ALD and aldosterone-to-renin ratio (ARR) post-ACTH stimulation obtained from controls, 30 patients (27%) exhibited an ALD but not cortisol (F) hyper-response (HYPER group). This group had no difference in basal ACTH/renin (REN) concentrations compared with controls and the 83 patients with hypertension (73%) without an ALD hyper-response to ACTH stimulation. Patients in the HYPER group demonstrated significantly higher ALD concentrations, ARR, and ALD/ACTH ratio (AAR) in the treadmill test. Treatment with MRAs alone produced normalization of blood pressure in these patients whereas patients with hypertension with neither PA nor ALD hyper-response to ACTH stimulation who served as a control group failed to lower blood pressure. Also, two novel germline heterozygous KCNJ5 mutations were detected in the HYPER group.

CONCLUSIONS

A number of patients with hypertension without PA show ACTH-dependent ALD hyper-secretion and benefit from treatment with MRAs. This could be related to chronic stress via ACTH hyper secretion and/or gene-mutations increasing the zona glomerulosa responsiveness to excitatory stimuli.

Progress in aldosteronism: a review of the prevalence of primary aldosteronism in pre-hypertension and hypertension

Primary aldosteronism (PA) secondary to excessive and/or autonomous aldosterone secretion from the renin-angiotensin system accounts for ∼10% of cases of hypertension and is primarily caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenomas (APAs). Although the diagnosis has traditionally been supported by low serum potassium levels, normokalaemic and even normotensive forms of PA have been identified expanding further the clinical phenotype. Moreover, recent evidence has shown that serum aldosterone correlates with increased blood pressure (BP) in the general population and even moderately raised aldosterone levels are linked to increased cardiovascular morbidity and mortality. In addition, aldosterone antagonists are effective in BP control even in patients without evidence of dysregulated aldosterone secretion. These findings indicate a higher prevalence of aldosterone excess among hypertensive patients than previously considered that could be attributed to disease heterogeneity, aldosterone level fluctuations related to an ACTH effect or inadequate sensitivity of current diagnostic means to identify apparent aldosterone excess. In addition, functioning aberrant receptors expressed in the adrenal tissue have been found in a subset of PA cases that could also be related to its pathogenesis. Recently a number of specific genetic alterations, mainly involving ion homeostasis across the membrane of zona glomerulosa, have been detected in ∼50% of patients with APAs. Although specific genotype/phenotype correlations have not been clearly identified, differential expression of these genetic alterations could also account for the wide clinical phenotype, variations in disease prevalence and performance of diagnostic tests. In the present review, we critically analyse the current means used to diagnose PA along with the role that ACTH, aberrant receptor expression and genetic alterations may exert, and provide evidence for an increased prevalence of aldosterone dysregulation in patients with essential hypertension and pre-hypertension.