Arterial stiffness and blood pressure improvement in aldosterone-producing adenoma harboring KCNJ5 mutations after adrenalectomy

Cardiovascular Outcomes of KCNJ5 Mutated Aldosterone-Producing Adenoma: A Systematic Review

BACKGROUND

While clinical features of KCNJ5-mutated aldosterone-producing adenoma (APA) have been reported, evidence of its clinical outcomes is lacking. We aimed to synthesize available literature about the associations between KCNJ5 mutation with cardiovascular and metabolic outcomes among patients with APA.

METHODS

In this systematic review of observational studies, MEDLINE and Embase were searched through August 2022. Two independent authors screened the search results and extracted data from eligible observational studies investigating cardiovascular or metabolic outcomes between KCNJ5-mutated APAs and KCNJ5-non-mutated APAs. Risk of Bias In Non-randomized Studies of Interventions was used to assess the quality of the included studies.

RESULTS

A total of 573 titles/abstracts were screened and after the expert opinion of the literature, full text was read in 20 titles/abstracts, of which 12 studies were included. Across 3 studies comparing the baseline or change in the cardiac function between KCNJ5-mutated APAs and KCNJ5-non-mutated APAs, all studies reported the association between impaired cardiac functions and KCNJ5 mutation status. Among 6 studies evaluating the cure of hypertension after surgery, all studies showed that KCNJ5 mutation was significantly associated with the cure of hypertension. In quality assessment, 7 studies were at serious risk of bias, while the remaining studies were at moderate risk of bias.

CONCLUSIONS

This systematic review provided evidence of the significant association between KCNJ5 mutation and unfavorable cardiovascular outcomes in patients with primary aldosteronism. Further research is needed to improve the quality of evidence on this topic and elucidate the underlying mechanisms of the potential burden of KCNJ5 mutation.

Comparisons of risk factors for post-treatment renal dysfunction between the two major subtypes of primary aldosteronism

OBJECTIVE

Aldosterone-producing adenoma (APA) and bilateral idiopathic hyperaldosteronism (IHA) are the most common subtypes of primary aldosteronism (PA), and the PA subtype dictates the treatment options. This study aimed to identify predictors of declined estimated glomerular filtration rate (eGFR) following each treatment in patients with APA and IHA.

METHODS

We retrospectively investigated 45 patients with APA who had undergone adrenalectomy (ADX) and 37 patients with IHA who had received treatment with a mineralocorticoid receptor antagonist (MRA) to identify pre-treatment risk factors for eGFR decline during the post-treatment follow-up period.

RESULTS

Patients with APA who underwent ADX exhibited higher eGFR declines than patients with IHA treated with MRA at the 6-month post-treatment evaluation point. A high preoperative plasma aldosterone concentration (PAC) in patients with APA and a high body mass index (BMI) in patients with IHA were identified as independent predictors of higher eGFR decline at 6 months post-treatment (β=0.42 and β=0.36, respectively). In patients with APA, the cutoff PAC to best predict a 20% decrease in eGFR following ADX, as determined by receiver operating characteristic analysis, was 524 pg/mL. In patients with IHA, the cutoff BMI to best predict a 10% decrease in eGFR following MRA administration was 25.3 kg/m2. In addition, lower preoperative flow-mediated vasodilation was associated with eGFR decline after ADX in patients with APA.

CONCLUSIONS

Greater attention should be given to the above-mentioned risk factors to prevent renal impairment following each treatment in patients with both APA and IHA.

Implication of MR Activity in Posttreatment Arterial Stiffness Reversal in Patients With Primary Aldosteronism

CONTEXT

Primary aldosteronism (PA) patients have a higher degree of arterial stiffness, which can be reversed after adrenalectomy.

OBJECTIVE

We aimed to compare the reversal of arterial stiffness between surgically and medically treated PA patients and to identify the predictors of effective medical treatment.

METHODS

We prospectively enrolled 445 PA patients and collected data on baseline clinical characteristics, biochemistry, blood pressure, and pulse wave velocity (PWV) before treatment and 12 months after treatment. In the mineralocorticoid receptor antagonist (MRA)-treated patients, the relationship between the change in PWV after 1 year (ΔPWV) and posttreatment renin activity was explored using the restricted cubic spline (RCS) method.

RESULTS

Of the 445 enrolled PA patients, 255 received adrenalectomy (group 1) and 190 received MRAs. In the RCS model, posttreatment plasma renin activity (PRA) 1.5 ng/mL/h was the best cutoff value. Therefore, we divided the MRA-treated patients into 2 groups: those with suppressed PRA (< 1.5 ng/mL/h, group 2), and those with unsuppressed PRA (≥ 1.5 ng/mL/h, group 3). Only group 1 and group 3 patients had a statistically significant improvement in PWV after treatment (both P < .001), whereas no significant improvement was noted in group 2 after treatment (P = .151). In analysis of variance and post hoc analysis, group 2 had a significantly lower ΔPWV than group 1 (P = .007) and group 3 (P = .031). Multivariable regression analysis of the MRA-treated PA patients identified log-transformed posttreatment PRA, age, and baseline PWV as independent factors correlated with ΔPWV.

CONCLUSION

The reversal of arterial stiffness was found in PA patients receiving adrenalectomy and in medically treated PA patients with unsuppressed PRA.

Cardiovascular and metabolic characters of KCNJ5 somatic mutations in primary aldosteronism

BACKGROUND

Primary aldosteronism (PA) is the leading cause of curable endocrine hypertension, which is associated with a higher risk of cardiovascular and metabolic insults compared to essential hypertension. Aldosterone-producing adenoma (APA) is a major cause of PA, which can be treated with adrenalectomy. Somatic mutations are the main pathogenesis of aldosterone overproduction in APA, of which KCNJ5 somatic mutations are most common, especially in Asian countries. This article aimed to review the literature on the impacts of KCNJ5 somatic mutations on systemic organ damage.

EVIDENCE ACQUISITION

PubMed literature research using keywords combination, including "aldosterone-producing adenoma," "somatic mutations," "KCNJ5," "organ damage," "cardiovascular," "diastolic function," "metabolic syndrome," "autonomous cortisol secretion," etc.

RESULTS

APA patients with KCNJ5 somatic mutations are generally younger, female, have higher aldosterone levels, lower potassium levels, larger tumor size, and higher hypertension cure rate after adrenalectomy. This review focuses on the cardiovascular and metabolic aspects of KCNJ5 somatic mutations in APA patients, including left ventricular remodeling and diastolic function, abdominal aortic thickness and calcification, arterial stiffness, metabolic syndrome, abdominal adipose tissue, and correlation with autonomous cortisol secretion. Furthermore, we discuss modalities to differentiate the types of mutations before surgery.

CONCLUSION

KCNJ5 somatic mutations in patients with APA had higher left ventricular mass (LVM), more impaired diastolic function, thicker aortic wall, lower incidence of metabolic syndrome, and possibly a lower incidence of concurrent autonomous cortisol secretion, but better improvement in LVM, diastolic function, arterial stiffness, and aortic wall thickness after adrenalectomy compared to patients without KCNJ5 mutations.

Heart-Ankle Pulse Wave Velocity Is Superior to Brachial-Ankle Pulse Wave Velocity in Detecting Aldosterone-Induced Arterial Stiffness

Primary aldosteronism (PA) is associated with higher arterial stiffness compared to essential hypertension (EH). However, few studies have compared different pulse wave velocity (PWV) parameters to detect aldosterone-induced arterial stiffness. In this study, we aimed to compare the sensitivity in detecting aldosterone-induced arterial stiffness between brachial-ankle PWV (baPWV) and heart-ankle PWV (haPWV). We prospectively enrolled 1006 PA patients and 983 EH patients. Detailed medical history, basic biochemistry data and two PWV measurements (baPWV and haPWV) were collected in both groups. We performed analysis on the original cohort and two propensity score matching (PSM) models (model 1 adjusted for age and sex; model 2 adjusted for age, sex, systolic and diastolic blood pressure). The DeLong test was used to compare areas under receiver operating characteristic curves (AUCs) between baPWV and haPWV to predict PA. In all models, the PA patients had significantly higher baPWV compared to the EH patients. The AUC of haPWV was greater than that of baPWV. In conclusion, haPWV seems to be a better PWV parameter than baPWV in detecting aldosterone-induced arterial stiffness.

KCNJ5 Somatic Mutations in Aldosterone-Producing Adenoma Are Associated with a Greater Recovery of Arterial Stiffness

Simple Summary

Primary aldosteronism (PA) is the most common form of secondary hypertension and induces various cardiovascular injuries. Aldosterone-producing adenoma (APA) is one of the major forms of PA. The occurrence of APA is closely correlated with somatic mutations, including KCNJ5. We described here the impact of KCNJ5 somatic mutations on arterial stiffness excluding the influence of age, sex, and blood pressure status. We found KCNJ5 mutation carriers had similar arterial stiffness before surgery, but greater improvement of arterial stiffness after adrenalectomy compared with non-carriers. Hence, APA patients with KCNJ5 mutations had a greater improvement in arterial stiffness after adrenalectomy than those without mutations.

Abstract

Primary aldosteronism is the most common form of secondary hypertension and induces various cardiovascular injuries. In aldosterone-producing adenoma (APA), the impact of KCNJ5 somatic mutations on arterial stiffness excluding the influence of confounding factors is uncertain. We enrolled 213 APA patients who were scheduled to undergo adrenalectomy. KCNJ5 gene sequencing of APA was performed. After propensity score matching (PSM) for age, sex, body mass index, blood pressure, number of hypertensive medications, and hypertension duration, there were 66 patients in each group with and without KCNJ5 mutations. The mutation carriers had a higher aldosterone level and lower log transformed brachial–ankle pulse wave velocity (baPWV) than the non-carriers before PSM, but no difference in log baPWV after PSM. One year after adrenalectomy, the mutation carriers had greater decreases in log plasma aldosterone concentration, log aldosterone–renin activity ratio, and log baPWV than the non-carriers after PSM. Only the mutation carriers had a significant decrease in log baPWV after surgery both before and after PSM. KCNJ5 mutations were not correlated with baseline baPWV after PSM but were significantly correlated with ∆baPWV after surgery both before and after PSM. Conclusively, APA patients with KCNJ5 mutations had a greater regression in arterial stiffness after adrenalectomy than those without mutations.

Clinical impacts of endothelium-dependent flow-mediated vasodilation assessment on primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is divided into two major subtypes, aldosterone-producing adenoma (APA) and bilateral idiopathic hyperplasia (IHA) and is associated with a higher risk of cardiovascular events. However, the nature of vascular function in PA patients remains to be determined. The aim of this study was to determine the vascular function and investigate the implications of vascular function assessments in the patients.

METHODS

Flow-mediated dilation (FMD), as an index of endothelial function, and cardio-ankle vascular index (CAVI), as an index of arterial stiffness, were retrospectively compared between 42 patients with APA, 37 patients with IHA, and 42 patients with essential hypertension (EH). These values were also compared with background factors, KCNJ5 mutation and clinical outcome in terms of blood pressure reduction after adrenalectomy in the APA group.

RESULTS

FMD was significantly lower in the APA group (4.8 ± 2.1%) and IHA group (4.1 ± 1.9%) than in the EH group (5.7 ± 2.1%). CAVI did not differ significantly among groups. Although no significant correlations were seen between FMD and background factors in the IHA group, FMD correlated negatively with BMI and plasma aldosterone concentration in the APA group (rs = -0.313, rs = -0.342, respectively). KCNJ5 mutational status was not associated with FMD value. High FMD was associated with blood pressure normalization after adrenalectomy in the APA group.

CONCLUSIONS

Patients with PA displayed impaired endothelial function. Complete clinical success after adrenalectomy was associated with preserved endothelial function. This study provides a better understanding of FMD assessment in patients with PA.

Brachial-Ankle Pulse Wave Velocity as a Novel Modality for Detecting Early Diabetic Nephropathy in Type 2 Diabetes Patients

Brachial-ankle pulse wave velocity (baPWV) has been shown to correlate with a host of disorders associated with arterial stiffness. Type 2 diabetes is associated with the involvement of both small vessels and large vessels. Studies on the relevance of baPWV to early diabetic nephropathy are scarce. This retrospective observational case-control study enrolled 120 patients with type 2 diabetes from our medical records. We classified patients into two groups depending on the magnitude of albuminuria: 60 patients with microalbuminuria were classified as the early diabetic nephropathy group (EDN group) and 60 patients without albuminuria were classified as the diabetes without nephropathy group (DWN group). An additional 30 nondiabetic age- and sex-matched controls were also enrolled. Data regarding the lipid profile, blood pressure, baPWV, high-sensitivity C reactive protein (hs-CRP) level, anthropometric measurements, urine albumin/creatinine ratio (UACR), serum creatinine level, and glycemic control indices (i.e., fasting plasma glucose (FPG), postprandial glucose (PPG), and glycosylated hemoglobin (hemoglobin A1c, HbA1c)) were recorded for all enrolled participants. baPWV was significantly higher in the EDN group than in the DWN group. Moreover, baPWV was positively correlated with age, duration of diabetes, obesity, poor glycemic control, and high serum levels of triglycerides (TG), hs-CRP, creatinine, and uric acid as well as a high UACR (all P < 0.01). A significant negative correlation was found between baPWV and high-density lipoprotein levels (P < 0.05). Multivariate regression analysis showed that the hs-CRP level and duration of diabetes most strongly influenced baPWV. baPWV may be a convenient, noninvasive, and reproducible method for detecting early diabetic nephropathy.

Hyperaldosteronism: How Current Concepts Are Transforming the Diagnostic and Therapeutic Paradigm

Nearly seven decades have elapsed since the clinical and biochemical features of primary hyperaldosteronism (PA) were described by Conn. PA is now widely recognized as the most common form of secondary hypertension. PA has a strong correlation with cardiovascular disease and failure to recognize and/or properly diagnose this condition has profound health consequences. With proper identification and management, PA has the potential to be surgically cured in a proportion of affected individuals. The diagnostic pursuit for PA is not a simplistic endeavor, particularly because an enhanced understanding of the disease process is continually redefining the diagnostic and treatment algorithm. These new concepts have emerged in all areas of this clinical condition, including identification, diagnosis, and treatment. Here, we review the recent advances in this field and summarize the effect these advances have on both diagnostic and therapeutic modalities.

Adrenalectomy Completely Cured Hypertension in Patients With Familial Hyperaldosteronism Type I Who Had Somatic KCNJ5 Mutation

CONTEXT

Familial hyperaldosteronism type I (FH-I) or glucocorticoid-remediable aldosteronism (GRA) is caused by unequal crossing over of the steroid 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes. Somatic KCNJ5 mutations have not been reported in patients with GRA; therefore, the appropriate treatment and prognosis of such concurrent cases remain unknown.

CASE DESCRIPTION

Two siblings of a Taiwanese family with GRA were found to have adrenal adenomas and somatic KCNJ5 mutations. Complete clinical cure was achieved after unilateral adrenalectomy. Furthermore, the conversion site of the chimeric gene was identified by direct sequencing.

CONCLUSIONS

We report the coexistence of a somatic KCNJ5 mutation and GRA. Patients with GRA whose blood pressure management develops resistance to glucocorticoid treatment could therefore benefit from a lateralization test. The promising outcomes after unilateral adrenalectomy presented in this report offer new perspectives for further research into various PA subtypes.

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.

Adrenalectomy Improves the Long-Term Risk of End-Stage Renal Disease and Mortality of Primary Aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is a common cause of secondary hypertension, and the long-term effect of excess aldosterone on kidney function is unknown.

PATIENTS AND METHODS

We used a longitudinal population database from the Taiwan National Health Insurance system and applied a validated algorithm to identify patients with PA diagnosed between 1997 and 2009.

RESULTS

There were 2699 patients with PA recruited, of whom 761 patients with an aldosterone-producing adenoma (APA) were identified. The incidence rate of end-stage renal disease (ESRD) was 3% in patients with PA after targeted treatments and 5.2 years of follow-up, which was comparable to the rate in controls with essential hypertension (EH). However, after taking mortality as a competing risk, we found a significantly lower incidence of ESRD when comparing patients with PA vs EH [subdistribution hazard ratio (sHR), 0.38; P = 0.007] and patients with APA vs EH (sHR 0.55; P = 0.021) after adrenalectomy; however, we did not see similar results in groups with mineralocorticoid receptor antagonist (MRA)‒treated PA vs EH. There was also a significantly lower incidence of mortality in groups with PA and APA who underwent adrenalectomy than among EH controls (P < 0.001).

CONCLUSION

Regarding incident ESRD, patients with PA were comparable to their EH counterparts after treatment. After adrenalectomy, patients with APA had better long-term outcomes regarding progression to ESRD and mortality than hypertensive controls, but MRA treatments did not significantly affect outcome.

Higher Screening Aldosterone to Renin Ratio in Primary Aldosteronism Patients with Diabetes Mellitus

Accumulated evidence has shown that low renin hypertension is common in patients with diabetic nephropathy. However, the performance of aldosterone to renin ratio (ARR) in primary aldosteronism (PA) patients with diabetes has not been well validated. Here, we report the performance of screening ARR in PA patients with diabetes. The study enrolled consecutive patients and they underwent ARR testing at screening. Then the diagnosis of PA was confirmed from the Taiwan Primary Aldosteronism Investigation registration dataset. Generalized additive model smoothing plot was used to validate the performance of screening ARR in PA patients with or without diabetes. During this study period, 844 PA patients were confirmed and 136 (16.0%) among them had diabetes. Other 816 patients were diagnosed with essential hypertension and used as the control group and 89 (10.9%) among them had diabetes. PA patients with diabetes were older and had a longer duration of hypertensive latency, higher systolic blood pressure and lower glomerular filtration rate than those PA patients without diabetes. The cut-off value of ARR in the generalized additive model predicting PA was 65 ng/dL per ng/mL/h in diabetic patients, while 45 ng/dL per ng/mL/h in non-diabetic patients. There was a considerable prevalence of diabetes among PA patients, which might be capable of interfering with the conventional screening test. The best cut-off value of ARR, more than 65 ng/dL per ng/mL/h in PA patients with diabetes, was higher than those without diabetes.

Comparative Genomics and Transcriptome Profiling in Primary Aldosteronism

Primary aldosteronism is the most common form of endocrine hypertension with a prevalence of 6% in the general population with hypertension. The genetic basis of the four familial forms of primary aldosteronism (familial hyperaldosteronism FH types I–IV) and the majority of sporadic unilateral aldosterone-producing adenomas has now been resolved. Familial forms of hyperaldosteronism are, however, rare. The sporadic forms of the disease prevail and these are usually caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Aldosterone-producing adenomas frequently carry a causative somatic mutation in either of a number of genes with the KCNJ5 gene, encoding an inwardly rectifying potassium channel, a recurrent target harboring mutations at a prevalence of more than 40% worldwide. Other than genetic variations, gene expression profiling of aldosterone-producing adenomas has shed light on the genes and intracellular signalling pathways that may play a role in the pathogenesis and pathophysiology of these tumors.