Primary Aldosteronism: Diagnosis and Management

Cardiovascular Remodeling in Chronic Mineralocorticoid Excess

Primary hyperaldosteronism typically leads to resistant hypertension, hypokalemia, and metabolic alkalosis. Excess aldosterone secretion by the adrenal glands may lead to heart failure with preserved ejection fraction. Potassium-sparing diuretics and aldosterone antagonists directed to lower excess aldosterone levels may help treat the associated heart failure and lead to control of blood pressure, resulting in improved outcomes. We report a case of a 55-year-old male with poorly controlled hypertension and newly symptomatic heart failure with preserved ejection fraction in the setting of excess aldosterone activity and an adrenal adenoma suggesting primary aldosteronism-induced diastolic heart failure. The biochemical evaluation revealed elevated plasma aldosterone concentrations with low plasma renin activity, diuretic-induced hypokalemia, and metabolic alkalosis. A progressively enlarging left adrenal adenoma was found on abdominal imaging along with resistant hypertension despite the use of multiple antihypertensive medications. Medical management targeted to lower excess aldosterone levels with the use of aldosterone antagonists helped us achieve better blood pressure control and resolution of symptoms of diastolic dysfunction. Treating the underlying pathology helped us improve overt heart failure and may suggest that goal-directed therapy towards the inciting factors may potentially lead to a path to reverse the heart failure symptoms clinically.

Close Call From a Sweet Twist: A Case of Licorice-Induced Torsades De Pointes

Torsades de pointes (TdP) is a life-threatening cardiac arrhythmia that can result from QT interval prolongation, sometimes secondary to medication adverse effects and electrolyte derangements. We present a 95-year-old Hispanic male with advanced chronic kidney disease (CKD) that was evaluated for dizziness and progressive weakness. The diagnosis of severe symptomatic hypokalemia and QT prolongation was made, and the patient was admitted for telemetry monitoring and aggressive intravenous electrolyte replacements. While under observation, the patient experienced syncope due to ventricular tachycardia (VT) with episodes of torsades de pointes. Due to refractory potassium depletion and hypertension, workup for hyperaldosteronism revealed renal potassium wasting, inappropriately normal plasma renin levels, and almost undetectable aldosterone levels. Careful analysis revealed the excessive chronic daily ingestion of licorice-containing candy twists and tea, which may cause pseudohyperaldosteronism. Licorice is a commonly used natural product that is available in many forms. It is sometimes used as a natural supplement and as a sweetener that can be widely found in many food products. Excessive ingestion can lead to apparent mineralocorticoid excess, reduced plasma potassium, sodium retention, hypertension, and metabolic alkalosis. Hypokalemia can be severe in some patients and lead to fatal cardiac arrhythmias such as ventricular tachycardia and torsades de pointes. Careful analysis is essential in cases of refractive hypokalemia and renal potassium wasting, especially in elderly patients with underlying renovascular disease.

Aldosterone Suppresses Endothelial Mitochondria through Mineralocorticoid Receptor/Mitochondrial Reactive Oxygen Species Pathway

Excessive aldosterone secretion causes endothelial dysfunction, vascular inflammation, and vascular fibrosis in patients with primary aldosteronism (PA). Endothelial function is closely related to endothelial mitochondria. However, the effects of elevated aldosterone levels on endothelial mitochondria remain unclear. In this study, we used primary cultured human umbilical vein endothelial cells (HUVECs) to investigate the effects of aldosterone on endothelial mitochondria. Mineralocorticoid receptor (MR) small interfering (si)RNA or glucocorticoid receptor (GR) siRNA were used to confirm the pathway by which aldosterone exerts its effects on the mitochondria of HUVECs. The results showed that excess aldosterone suppressed mitochondrial DNA copy numbers, anti-mitochondrial protein, and SOD2 protein expression in a dose- and time-dependent manner. These effects were attenuated by treatment with MR siRNA, but not with GR siRNA. Furthermore, it was attenuated by treatment with a mitochondria-targeted antioxidant (Mito-TEMPO, associated with mitochondrial reactive oxygen species (ROS) production), but not N-acetyl-L-cysteine (associated with cytosolic ROS production), which suggests that the process was through the mitochondrial ROS pathway, but not the cytosolic ROS pathway. In conclusion, aldosterone excess suppressed endothelial mitochondria through the MR/mitochondrial ROS pathway.

Clinical characteristics of concurrent primary aldosteronism and renal artery stenosis: A retrospective case-control study

Background: Rare cases of concurrent primary aldosteronism (PA) and renal artery stenosis (RAS) have been reported. Methods: In this retrospective case-control study, we selected a cohort of 10 PA with RAS patients and a control group of 20 PA without RAS patients from January 1, 2006, to January 1, 2016.  Results: All patients presented with refractory hypertension, and a nonstatistically significant trend toward lower mean serum potassium was seen in the PA with RAS group (p =.07). PA with RAS patients had lower mean orthostatic aldosterone-to-renin ratios (38.4 ± 41.4 ng dL^-1/ng mL^-1 h^-1 vs. 87.4.4 ± 38.4 ng dL^-1/ng mL^-1 h^-1, respectively; p < .01) and a higher false-negative rate (50% vs. 15%, respectively; p < .05) compared with controls. All misdiagnosed patients had the diagnosis of PA confirmed when we revaluated the repeated screening and confirmative tests because of residual hypertension or hypokalemia after successful revascularization of renal artery stenosis.  Conclusions: PA is easily missed in patients with RAS because of the high false-negative rate for screening tests. RAS patients with residual hypertension after successful renal angioplasty should be monitored for coexisting PA. Reevaluation of screening and confirmatory tests is helpful in establishing the correct diagnoses.

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.

Endothelial Dysfunction in Primary Aldosteronism

Primary aldosteronism (PA) is characterized by excess production of aldosterone from the adrenal glands and is the most common and treatable cause of secondary hypertension. Aldosterone is a mineralocorticoid hormone that participates in the regulation of electrolyte balance, blood pressure, and tissue remodeling. The excess of aldosterone caused by PA results in an increase in cardiovascular and cerebrovascular complications, including coronary artery disease, myocardial infarction, stroke, transient ischemic attack, and even arrhythmia and heart failure. Endothelial dysfunction is a well-established fundamental cause of cardiovascular diseases and also a predictor of worse clinical outcomes. Accumulating evidence indicates that aldosterone plays an important role in the initiation and progression of endothelial dysfunction. Several mechanisms have been shown to contribute to aldosterone-induced endothelial dysfunction, including aldosterone-mediated vascular tone dysfunction, aldosterone- and endothelium-mediated vascular inflammation, aldosterone-related atherosclerosis, and vascular remodeling. These mechanisms are activated by aldosterone through genomic and nongenomic pathways in mineralocorticoid receptor-dependent and independent manners. In addition, other cells have also been shown to participate in these mechanisms. The complex interactions among endothelium, inflammatory cells, vascular smooth muscle cells and fibroblasts are crucial for aldosterone-mediated endothelial dysregulation. In this review, we discuss the association between aldosterone and endothelial function and the complex mechanisms from a molecular aspect. Furthermore, we also review current clinical research of endothelial dysfunction in patients with PA.

A case of primary aldosteronism with resistant hypertension successfully treated by unilateral adrenalectomy after unsuccessful classification of subtype in adrenal venous sampling

Despite being an established method to identify the unilateral subtype of primary aldosteronism with an indication of adrenalectomy, adrenal venous sampling sometimes fails primarily due to unsuccessful cannulation to adrenal veins. In such cases, the analysis of clinical findings might help to identify the indication of surgery.

Aldosterone induces left ventricular subclinical systolic dysfunction: a strain imaging study

BACKGROUND

Primary aldosteronism is associated with a higher incidence of left ventricular (LV) hypertrophy and diastolic dysfunction than essential hypertension. However, systolic function via endocardial measurements is similar between patients with primary aldosteronism and essential hypertension. Speckle-tracking echocardiography is a sensitive tool which can detect subclinical impairments in systolic function. The aim of this study was to investigate aldosterone-induced subclinical impairments in systolic function.

METHODS

We prospectively enrolled patients with primary aldosteronism and essential hypertension and analyzed their clinical data, biochemical data, and echocardiographic parameters, including myocardial strain [global longitudinal strain (GLS)].

RESULTS

Thirty-six patients with primary aldosteronism and 31 patients with essential hypertension were enrolled for analysis. The patients with primary aldosteronism had significantly lower serum potassium levels, lower plasma renin activity, higher aldosterone-to-renin ratio (ARR), and higher 24-h urinary aldosterone levels than patients with essential hypertension. With regards to echocardiographic parameters, the patients with primary aldosteronism had a thicker ventricular wall and higher LV mass index than those with essential hypertension. Most importantly, we found significant degradation of GLS in the patients with primary aldosteronism compared with those with essential hypertension (-17.84 ± 2.36 vs. -20.13 ± 2.32, P < 0.001). In correlation analysis, GLS was significantly correlated with serum potassium level, LV mass index, log-transformed plasma renin activity, log-transformed ARR, and log-transformed 24-h urinary aldosterone levels (all P < 0.05). Multivariate linear regression analysis further identified log-transformed ARR (β = 0.771, 95% confidence interval: 0.011-1.530, P = 0.047), and log-transformed 24-h urinary aldosterone level (β = 1.765, 95% confidence interval: 0.01-3.529, P = 0.050) as independent factors correlated with GLS.

CONCLUSION

Patients with primary aldosteronism have a lower magnitude of GLS than patients with essential hypertension, suggesting that aldosterone induces a subclinical decline in LV systolic function.

Primary Aldosteronism and Cerebrovascular Diseases

As diagnostic techniques have advanced, primary aldosteronism (PA) has emerged as the most common cause of secondary hypertension. The excess of aldosterone caused by PA resulted in not only cardiovascular complications, including coronary artery disease, myocardial infarction, arrhythmia, and heart failure, but also cerebrovascular complications, such as stroke and transient ischemic attack. Moreover, PA is associated more closely with these conditions than is essential hypertension. In this review, we present up-to-date findings on the association between PA and cerebrovascular diseases.

Liddle syndrome misdiagnosed as primary aldosteronism resulting from a novel frameshift mutation of SCNN1B

Liddle syndrome (LS), a monogenetic autosomal dominant disorder, is mainly characterized by early-onset hypertension and hypokalemia. Clinically, misdiagnosis or missing diagnosis is common, since clinical phenotypes of LS are variable and nonspecific. We report a family with misdiagnosis of primary aldosteronism (PA), but identify as LS with a pathogenic frameshift mutation of the epithelial sodium channel (ENaC) β subunit. DNA samples were collected from a 32-year-old proband and 31 other relatives in the same family. A designed panel including 41 genes associated with monogenic hypertension was screened using next-generation sequencing. The best candidate disease-causing variants were verified by Sanger sequencing. Genetic analysis of the proband revealed a novel frameshift mutation c.1838delC (p.Pro613Glnfs*675) in exon 13 of SCNN1B. This heterozygous mutation involved the deletion of a cytosine from a string of three consecutive cytosines located at codons 612 to 613 and resulted in deletion of the crucial PY motif and elongation of the β-ENaC protein. The identical mutation was also found in 12 affected family members. Amiloride was effective in alleviating LS for patients. There were no SCNN1A or SCNN1G mutations in this family. Our study emphasizes the importance of considering LS in the differential diagnosis of early-onset hypertension. The identification of a novel frameshift mutation of SCNN1B enriches the genetic spectrum of LS and has allowed treatment of this affected family to prevent severe complications.

Primary aldosteronism with nonlocalizing imaging

BACKGROUND

Unilateral primary aldosteronism is surgically curable. The goal of this study was to examine outcomes based on preoperative imaging findings.

METHODS

We performed a retrospective analysis of patients with primary aldosteronism who underwent adrenal vein sampling. Patients were classified by imaging as localized (unilateral adrenal mass) or nonlocalized (no mass/bilateral masses). Outcomes were assessed as complete, partial, or absent clinical success.

RESULTS

Of 446 patients, 74.9% were localized. There were no significant demographic or biochemical differences between groups; however the imaged tumor size was larger (median 1.3 vs 1.2 cm, P = .038), and rates of lateralizing adrenal vein sampling were higher (79.0% vs 62.2%, P < .001) in the localized group. Of 289 patients who underwent adrenalectomy, adenoma was the most common finding in both groups (79.7% vs 80.3% respectively, P = .447), but median tumor size was larger in localized patients (1.5 vs 1.0 cm, P < .001). Equivalent rates of partial (94.6% vs 91.7%, P = .456) and complete (8.7% vs 9.8%, P = .801) clinical success were observed. At long-term follow-up, nonlocalized patients experienced partial reversal of clinical improvement.

CONCLUSION

Primary aldosteronism patients with nonlocalizing imaging but lateralizing adrenal vein sampling benefit from adrenalectomy. Regardless of imaging findings, adrenal vein sampling is indicated to determine whether patients may be surgically curable.