Spironolactone improves endothelial and cardiac autonomic function in non heart failure hemodialysis patients

Mineralocorticoid Receptor Antagonist versus Placebo in a Patient With End-Stage Kidney Disease Under Renal Replacement Therapy: A Systematic Review and Meta-Analysis

ABSTRACT

The number of patients living with chronic kidney diseases is increasing, and so are the patients with end-stage renal disease (ESRD) undergoing renal replacement therapy. Although there is a common understanding that these patients face higher risks of fatal or nonfatal cardiovascular and cerebrovascular events, and mineralocorticoid receptor antagonists (MRAs) have been an essential pillar in managing heart failure, their use in this subset of patients has been overshadowed because of concerns of hyperkalemia. Patients with ESRD under renal replacement therapy have often been excluded from landmark trials. This meta-analysis was conducted based on the PRISMA guideline after registering the protocol with PROSPERO (CRD42024499835). A database search included articles until April 2024, and relevant data were extracted from the included studies. Analysis was done using RevMan web (version 5.4). A total of 15 studies among 1086 studies were included in the final analysis. Our meta-analysis revealed MRA significantly reduced all-cause mortality (odds ratio (OR) 0.35, confidence interval (CI), 0.23-0.54) and cardiovascular mortality (OR 0.37, 0.21-0.65). With some possible increase in the risk of hyperkalemia (OR 1.56, CI, 1.01-2.42), with no discernible difference in the occurrence of stroke (OR 0.57, CI, 0.25-1.28) or myocardial infarction (OR 0.63, CI, 0.08-4.72). The utilization of MRA in patients with ESRD under dialysis is linked to improved mortality outcomes, albeit with slight concerns for hyperkalemia. Although current evidence leans toward MRA usage, prospective randomized controlled trials involving a broader patient cohort are essential to establish robust guidance for MRA application in this subset of patients.

Effects of spironolactone on intradialytic hypertension: a multicentre, double-blind, randomized, crossover study

Background

Intradialytic hypertension (IDH) is associated with an increase in hospitalization and mortality. Several studies have shown that spironolactone reduces pre-dialysis blood pressure. However, none evaluated its effect on IDH. This study aims to evaluate the effects of spironolactone on IDH.

Methods

A 24-week, two-treatment, four-period, multicentre, double-blind, randomized, crossover study was conducted in stable maintenance haemodialysis (HD) patients who experienced IDH in >30% of their sessions during the past 3 months. Each participant was randomly assigned to one of four treatment sequences. In each intervention period, patients received a single dose of 50 mg spironolactone or a placebo 30 minutes before undergoing HD for 4 weeks according to their preassigned sequence, separated by a 2-week washout period. The primary outcome was an incidence of IDH.

Results

A total of 49 eligible patients were recruited with a total of 1211 dialysis sessions. The mean age was 54 ± 14 years and the mean systolic and diastolic blood pressures (SBP and DBP) were 145 ± 15 and 75 ± 10 mmHg, respectively. All patients had hypertension. The average number of antihypertensive drugs was 3.5 ± 1.4. Spironolactone reduced the incidence of IDH compared with placebo (57% versus 69%, P for treatment effect < .001). Patients receiving spironolactone had lower peak intradialytic SBP (161 ± 14 versus 165 ± 13 mmHg, P = .003), mean intradialytic SBP (149 ± 13 versus 152 ± 12 mmHg, P = .01) and post-dialysis SBP (152 ± 15 versus 157 ± 14 mmHg, P < .001) than placebo.

Conclusion

In maintenance HD patients who had frequent IDH, a pre-dialysis 50-mg spironolactone administration significantly decreased the incidence of IDH.

Trial registration

Thai Clinical Trial Registry, reference number TCTR20200604013.

Clinical Properties and Non-Clinical Testing of Mineralocorticoid Receptor Antagonists in In Vitro Cell Models

Mineralocorticoid receptor antagonists (MRAs) are one of the renin-angiotensin-aldosterone system inhibitors widely used in clinical practice. While spironolactone and eplerenone have a long-standing profile in clinical medicine, finerenone is a novel agent within the MRA class. It has a higher specificity for mineralocorticoid receptors, eliciting less pronounced adverse effects. Although approved for clinical use in patients with chronic kidney disease and heart failure, intensive non-clinical research aims to further elucidate its mechanism of action, including dose-related selectivity. Within the field, animal models remain the gold standard for non-clinical testing of drug pharmacological and toxicological properties. Their role, however, has been challenged by recent advances in in vitro models, mainly through sophisticated analytical tools and developments in data analysis. Currently, in vitro models are gaining momentum as possible platforms for advanced pharmacological and pathophysiological studies. This article focuses on past, current, and possibly future in vitro cell models research with clinically relevant MRAs.

Collagen turnover is associated with cardiovascular autonomic and peripheral neuropathy in type 1 diabetes: novel pathophysiological mechanism?

BACKGROUND

Diabetic cardiovascular autonomic neuropathy (CAN) and distal symmetrical polyneuropathy (DSPN) are severe diabetic complications. Collagen type VI (COL6) and III (COL3) have been associated with nerve function. We investigated if markers of COL6 formation (PRO-C6) and COL3 degradation (C3M) were associated with neuropathy in people with type 1 diabetes (T1D).

METHODS

In a cross-sectional study including 300 people with T1D, serum and urine PRO-C6 and C3M were obtained. CAN was assessed by cardiovascular reflex tests: heart rate response to deep breathing (E/I ratio), to standing (30/15 ratio) and to the Valsalva maneuver (VM). Two or three pathological CARTs constituted CAN. DSPN was assessed by biothesiometry. Symmetrical vibration sensation threshold above 25 V constituted DSPN.

RESULTS

Participants were (mean (SD)) 55.7 (9.3) years, 51% were males, diabetes duration was 40.0 (8.9) years, HbA1c was 63 (11 mmol/mol, (median (IQR)) serum PRO-C6 was 7.8 (6.2;11.0) ng/ml and C3M 8.3 (7.1;10.0) ng/ml. CAN and DSPN were diagnosed in 34% and 43% of participants, respectively. In models adjusted for relevant confounders a doubling of serum PRO-C6, was significantly associated with odds ratio > 2 for CAN and > 1 for DSPN, respectively. Significance was retained after additional adjustments for eGFR only for CAN. Higher serum C3M was associated with presence of CAN, but not after adjustment for eGFR. C3M was not associated with DSPN. Urine PRO-C6 analyses indicated similar associations.

CONCLUSIONS

Results show previously undescribed associations between markers of collagen turnover and risk of CAN and to a lesser degree DSPN in T1D.

Endothelial Cell Dysfunction and Increased Cardiovascular Risk in Patients With Chronic Kidney Disease

The endothelium is considered to be the gatekeeper of the vessel wall, maintaining and regulating vascular integrity. In patients with chronic kidney disease, protective endothelial cell functions are impaired due to the proinflammatory, prothrombotic and uremic environment caused by the decline in kidney function, adding to the increase in cardiovascular complications in this vulnerable patient population. In this review, we discuss endothelial cell functioning in healthy conditions and the contribution of endothelial cell dysfunction to cardiovascular disease. Further, we summarize the phenotypic changes of the endothelium in chronic kidney disease patients and the relation of endothelial cell dysfunction to cardiovascular risk in chronic kidney disease. We also review the mechanisms that underlie endothelial changes in chronic kidney disease and consider potential pharmacological interventions that can ameliorate endothelial health.

Safety and Efficacy of Spironolactone in Dialysis-Dependent Patients: Meta-Analysis of Randomized Controlled Trials

Background

Patients with end-stage renal disease (ESRD) are characterized with high risk of heart failure. Although mineralocorticoid receptor antagonists have beneficial effect on relieving cardiac fibrosis and, thus, reduce the incidence of cardiovascular disease and cardiac death, the therapeutic benefits and adverse effects are still controversial. We conducted a meta-analysis to measure the safety and efficacy of spironolactone in patients undergoing dialysis.

Methods

A systematic search for randomized controlled trials (RCTs) was performed in PubMed, Embase, and Cochrane databases. Primary outcomes included changes in all-cause mortality (ACM), serum potassium concentration, incidence of hyperkalemia and gynecomastia (GYN). Secondary outcomes included changes in blood pressure (BP), left ventricular mass index (LVMI) and left ventricular ejection fraction (LVEF). Subgroup analysis and sensitivity analysis were further conducted. This research was registered with PROSPERO (International Prospective Register of Systematic Reviews; No. CRD42021287493).

Results

Fifteen RCTs with 1,258 patients were enrolled in this pooled-analysis. Spironolactone treatment significantly decreased ACM (RR = 0.42, P < 0.0001), CCV (RR = 0.54, P = 0.008) and LVMI (MD = −6.28, P = 0.002), also increased occurrence of GYN (RR = 4.36, P = 0.0005). However, LVEF (MD = 2.63, P = 0.05), systolic BP (MD = −4.61, P = 0.14) and diastolic BP (MD = −0.12, P = 0.94) did not change between two groups after treatment. Although serum potassium concentration was increased (MD = 0.22, P < 0.0001) after spironolactone supplement, the risk of hyperkalemia remained unchanged (RR = 1.21, P = 0.31). Further subgroup analysis found more obvious advantageous as well as disadvantageous effects in Asian subjects than European or American ones. Also, with more than 9 months of treatment duration, patients achieved more favorable influence than shorter duration.

Conclusions

These results highlight the therapeutic effects of spironolactone on cardiovascular indexes, including ACM, CCV, and LVMI. However, the unignorable increase of GYN incidence and serum potassium level indicate that close monitor in dialysis-dependent patients, especially Asian patients, is essential.

Εndothelial and microvascular function in CKD: Evaluation methods and associations with outcomes

BACKGROUND

Cardiovascular disease is the major cause of morbidity and mortality in patients with chronic kidney disease (CKD). Endothelial dysfunction, the hallmark of atherosclerosis, is suggested to be involved pathogenetically in cardiovascular and renal disease progression in these patients.

METHODS

This is a narrative review presenting the techniques and markers used for assessment of microvascular and endothelial function in patients with CKD and discussing findings of the relevant studies on the associations of endothelial dysfunction with co-morbid conditions and outcomes in this population.

RESULTS

Venous Occlusion Plethysmography was the first method to evaluate microvascular function; subsequently, several relevant techniques have been developed and used in patients with CKD, including brachial Flow-Mediated Dilatation, and more recently, Near-Infrared Spectroscopy and Laser Speckle Contrast Analysis. Furthermore, several circulating biomarkers are commonly used in clinical research. Studies assessing endothelial function using the above techniques and biomarkers suggest that endothelial dysfunction occurs early in CKD and contributes to the target organ damage, cardiovascular events, death and progression towards end-stage kidney disease.

CONCLUSIONS

Older and newer functional methods and several biomarkers have assessed endothelial dysfunction in CKD; accumulated evidence supports an association of endothelial dysfunction with outcomes. Future research with new, non-invasive and easily applicable methods could further delineate the role of endothelial dysfunction on cardiovascular and renal disease progression in patients with CKD.

Mineralocorticoid Receptor Antagonist Use in Heart Failure With Reduced Ejection Fraction and End-Stage Renal Disease Patients on Dialysis: A Literature Review

Mineralocorticoid receptor antagonists (MRAs) are known to have a proven mortality benefit in heart failure with reduced ejection fraction (HFrEF) without kidney disease. As patients with end-stage renal disease (ESRD) requiring either peritoneal dialysis or hemodialysis were excluded in clinical trials of HFrEF, the data are scant on the appropriate use of MRAs in this population. The unknown efficacy, along with concerns of adverse effects such as hyperkalemia, has limited the willingness of clinicians to consider using MRAs in these patients. However, it is unclear whether the risk of hyperkalemia is present if a patient is oliguric or anuric. Current guidelines recommend against the use of MRAs in patients with chronic kidney disease, but do not address the use of MRAs in patients requiring dialysis. This article will review the epidemiology of heart failure in ESRD, the pathophysiological derangements of the renin-angiotensin-aldosterone system in patients with kidney disease, and the results from case series and trials of the use of MRAs in ESRD with HFrEF. Although limited to several small trials using MRAs in peritoneal and hemodialysis patients with or without HFrEF, the current literature appears to show the potential for clinical benefits with little risk.

Effects of spironolactone on extrasystoles and heart rate variability in haemodialysis patients: a randomised crossover trial

BACKGROUND

Spironolactone treatment reduces mortality in haemodialysis (HD) patients. The objective of this study was to evaluate if spironolactone affects cardiac electric activity in this population.

METHODS

Participants were randomised to start with spironolactone 50 mg daily or observation (12 weeks) with subsequent washout (6 weeks) and crossover to the other intervention (12 weeks). Long-term electrocardiograms were recorded and assessed with blinding to treatment. The primary outcome was premature ventricular complexes (PVC), and secondary outcomes were atrial premature contractions (APC) and heart rate variability (HRV).

RESULTS

Thirty participants were recruited, and data for 16 participants were included in the analysis. Treatment was associated with an increase in PVCs by 9.7 [95% confidence interval (CI): 1.5 to 18] h^-1. HRV time-domain variables increased during treatment, the standard deviation of all beat-to-beat intervals by 18 (95% CI: 3.3 to 32) milliseconds (ms) and the standard deviation of the averages of beat-to-beat intervals in all 5-min segments of the entire recording by 16 (95% CI: 1.5 to 30) ms. There were no significant differences in other variables.

CONCLUSION

Spironolactone treatment increases PVCs in HD, indicating a possible proarrhythmic effect. However, improved cardiac autonomic function, as indicated by an increased HRV, may contribute to the survival benefit from spironolactone treatment in HD patients.

Assessment of Endothelial and Microvascular Function in CKD: Older and Newer Techniques, Associated Risk Factors, and Relations with Outcomes

BACKGROUND

Endothelium is the inner cellular lining of the vessels that modulates multiple biological processes including vasomotor tone, permeability, inflammatory responses, hemostasis, and angiogenesis. Endothelial dysfunction, the basis of atherosclerosis, is characterized by an imbalance between endothelium-derived relaxing factors and endothelium-derived contracting factors.

SUMMARY

Starting from the semi-invasive venous occlusion plethysmography, several functional techniques have been developed to evaluate microvascular function and subsequently used in patients with CKD. Flow-mediated dilatation of the forearm is considered to be the "gold standard," while in the last years, novel, noninvasive methods such as laser speckle contrast imaging and near-infrared spectroscopy are scarcely used. Moreover, several circulating biomarkers of endothelial function have been used in studies in CKD patients. This review summarizes available functional methods and biochemical markers for the assessment of endothelial and microvascular function in CKD and discusses existing evidence on their associations with comorbid conditions and outcomes in this population. Key Messages: Accumulated evidence suggests that endothelial dysfunction occurs early in CKD and is associated with target organ damage, progression of renal injury, cardiovascular events, and mortality. Novel methods evaluating microvascular function can offer a detailed, real-time assessment of underlying phenomena and should be increasingly used to shed more light on the role of endothelial dysfunction on cardiovascular and renal disease progression in CKD.

The Crosstalk between Calcium Ions and Aldosterone Contributes to Inflammation, Apoptosis, and Calcification of VSMC via the AIF-1/NF-κB Pathway in Uremia

Vascular calcification is a major complication of maintenance hemodialysis patients. Studies have confirmed that calcification mainly occurs in the vascular smooth muscle cells (VSMC) of the vascular media. However, the exact pathogenesis of VSMC calcification is still unknown. This study shows that the crosstalk between calcium and aldosterone via the allograft inflammatory factor 1 (AIF-1) pathway contributes to calcium homeostasis and VSMC calcification, which is a novel mechanism of vascular calcification in uremia. In vivo results showed that the level of aldosterone and inflammatory factors increased in calcified arteries, whereas no significant changes were observed in peripheral blood. However, the expression of inflammatory factors markedly increased in the peripheral blood of uremic rats without aortic calcification and gradually returned to normal levels with aggravation of aortic calcification. In vitro results showed that there was an interaction between calcium ions and aldosterone in macrophages or VSMC. Calcium induced aldosterone synthesis, and in turn, aldosterone also triggered intracellular calcium content upregulation in macrophages or VSMC. Furthermore, activated macrophages induced inflammation, apoptosis, and calcification of VSMC. Activated VSMC also imparted a similar effect on untreated VSMC. Finally, AIF-1 enhanced aldosterone- or calcium-induced VSMC calcification, and NF-κB inhibitors inhibited the effect of AIF-1 on VSMC. These in vivo and in vitro results suggest that the crosstalk between calcium ions and aldosterone plays an important role in VSMC calcification in uremia via the AIF-1/NF-κB pathway. Local calcified VSMC induced the same pathological process in surrounding VSMC, thereby contributing to calcium homeostasis and accelerating vascular calcification.

Hyperkalemia and Acute Kidney Injury with Spironolactone Use Among Patients with Heart Failure

OBJECTIVE

To quantify the risk of hyperkalemia and acute kidney injury (AKI) when spironolactone use is added on to loop diuretic use among patients with heart failure, and to evaluate whether the risk is modified by level of kidney function.

METHODS

We identified 17,110 patients with heart failure treated with loop diuretics between January 1, 2004, and December 31, 2016 within the Geisinger Health System. We estimated the incidence of hyperkalemia and AKI associated with spironolactone initiation, and used target trial emulation methods to minimize confounding by indication.

RESULTS

During a mean follow-up of 134 mo, 3229 of 17,110 patients (18.9%) initiated spironolactone. Incidence rates of hyperkalemia and AKI in patients using spironolactone with a loop diuretic were 2.9 and 10.1 events per 1000 person-months, respectively. In propensity score-matched analyses, spironolactone initiation was associated with higher hyperkalemia and AKI risk compared with loop alone (hazard ratio, 1.69; 95% CI, 1.35 to 2.10; P<.001, and hazard ratio, 1.12; 95% CI, 1.00 to 1.26; P=.04, respectively). There were no differences in the relative risk of either outcome associated with spironolactone by level of kidney function.

CONCLUSION

The addition of spironolactone to loop diuretics in patients with heart failure was associated with higher risk of hyperkalemia and AKI; these risks must be weighed against the potential benefits of spironolactone.

Diagnosis and treatment of myocardial infarction in patient with end - stage renal disease on chronic hemodialysis

This review represents different aspects of myocardial infarction in patient with end - stage renal disease on chronic hemodialysis. We discuss difficulties in diagnosis, optimal method of coronary revascularization, timing of hemodialysis session, medical therapy, as well as epidemiology and prognosis. There are no unambiguous answers to these problems because patients with end - stage renal disease were excluded from most of the studies.

Effect of spironolactone for 1 yr on endothelial function and vascular inflammation biomarkers in renal transplant recipients

Kidney transplantation is associated with increased cardiovascular risk. Endothelial dysfunction and vascular inflammation contribute to negative outcome. In experimental models, mineralocorticoid receptor antagonists improved endothelial function and reduced inflammation. The present study tested the hypothesis that the mineralocorticoid receptor antagonist spironolactone improves endothelial function and reduces vascular inflammation in renal transplant patients. Eighty prevalent renal transplant patients from an ongoing, double-blind randomized placebo-controlled trial were included. Paired plasma samples before and after 1 yr of treatment (n = 39 in the spironolactone-treated group and 41 in the placebo-treated group) were used to determine markers of endothelial dysfunction (nitrite, nitrate, cGMP, arginine, citrulline, ornithine, asymmetric dimethylarginine, symmetric dimethylarginine, N^G-monomethyl-l-arginine, von Willebrand factor, tissue-type plasminogen activator antigen, and plasminogen activator inhibitor 1 antigen) and markers of inflammation (intercellular adhesion molecule, vascular adhesion molecule, high-sensitivity C-reactive protein, and serum amyloid protein A). The median time since the transplantation was 4.6 (0.12-22.3) yr in the spironolactone-treated group and 2.1 (0.17-13.9) yr in the placebo-treated group (P > 0.05). Spironolactone increased plasma aldosterone (P < 0.001) and K⁺ (P < 0.001). Blood pressure did not change significantly. No significant differences were detected between groups in any of the measured markers of endothelial dysfunction or inflammation except in the subgroup analysis of patients with diabetes, where spironolactone decreased nitrite compared with placebo. In this study, mineralocorticoid receptor antagonism did not improve biomarkers of endothelial dysfunction or vascular inflammation in prevalent renal transplant patients. Further studies are needed to evaluate the potential beneficial effect of early or late mineralocorticoid receptor antagonism on vascular outcomes in renal transplant patients.

A randomized controlled trial of the effect of spironolactone on left ventricular mass in hemodialysis patients

Mineralocorticoid receptor antagonists have beneficial effects on left ventricular remodeling, cardiac fibrosis, and arrhythmia in heart failure, but efficacy and safety in dialysis patients is less clear. We evaluated the effect of spironolactone on left ventricular mass (LVM), an independent predictor of all-cause and cardiovascular mortality, in hemodialysis patients. In this placebo-controlled, parallel-group trial, 97 hemodialysis patients (23% female; mean age 60.3 years) were randomized to spironolactone 50 mg once daily (n=50) or placebo (n=47). The primary efficacy endpoint was change in LVM index (LVMi) from baseline to 40 weeks as determined by cardiac magnetic resonance imaging. Safety endpoints were development of hyperkalemia and change in residual renal function. There was no significant change in LVMi in participants randomized to spironolactone compared to placebo (-2.86±11.87 vs. 0.41±10.84 g/m²). There was also no difference in the secondary outcomes of mean 24-hour systolic or diastolic ambulatory blood pressure, left ventricular ejection fraction, 6-minute walk test distance, or New York Heart Association functional class. Moderate hyperkalemia (pre-dialysis potassium levels of 6.0-6.5 mmol/L) was more frequent with spironolactone treatment (155 vs. 80 events), but severe hyperkalemia (≥6.5 mmol/L) was not (14 vs. 24 events). Changes in residual urine volume and measured glomerular filtration rate did not differ between groups. There were no deaths in the spironolactone group and 4 deaths in the placebo group. Thus, treatment with 50 mg spironolactone did not change left ventricular mass index, cardiac function, or blood pressure in hemodialysis patients. Spironolactone increased the frequency of moderate hyperkalemia, but did not increase severe hyperkalemia.

Mineralocorticoid Receptor Blockade in End-Stage Renal Disease

PURPOSE OF REVIEW

The purpose of this study was to summarize recent findings about cardiovascular benefits and safety of aldosterone blockade in patients with end-stage renal disease (ESRD).

RECENT FINDINGS

It is now well recognized that aldosterone's deleterious cardiovascular impact is not limited to its pressor effect arising from an increase in sodium reabsorption in the kidneys. Aldosterone has also been shown to increase blood pressure by a direct activation of the sympathetic nervous system, to cause endothelial and vascular smooth muscle cell dysfunction, myocardial remodeling and fibrosis, and to have pro-arrhythmogenic actions in the heart. These unconventional extra-renal effects of aldosterone make its blockade feasible and potentially beneficial for patients with ESRD. Accumulating data support the idea that aldosterone antagonism leads to a better blood pressure control, reduction in left ventricular (LV) mass, improved LV function, and reduced all-cause and cardiovascular mortality in ESRD patients. Reassuringly, rates of major adverse events, especially, significant hyperkalemia-the most feared adverse consequence-were low with careful patient selection and monitoring.

Aldosterone antagonist therapy and its relationship with inflammation, fibrosis, thrombosis, mineral-bone disorder and cardiovascular complications in peritoneal dialysis (PD) patients

Background

High aldosterone level may contribute to pathogenesis of hypertension, vessels damage and cardiovascular system deterioration in chronic kidney disease patients. Besides its classical action via mineralocorticoid receptor, aldosterone is also involved in cell growth, inflammation, oxidative stress, endothelial dysfunction and exerts fibroproliferative effects. The aim of the study was to assess whether aldosterone antagonist treatment may influence serum level of inflammatory, fibrosis, thrombosis and mineral-bone metabolism markers in peritoneal dialysis (PD) patients and blood pressure, aortic stiffness, echocardiographic indices after 12 months of treatment.

Methods

Twenty-two patients on PD were assigned to spironolactone treatment in dose of 50 mg daily during 12 months. Fifteen PD patients were assigned to control group. Echocardiographic indices, PVW, SBP, DBP (mean values from ABPM) and biochemical parameters such as: aldosterone, osteopontin, IL-6, selectin-P, TGF-β, PTH, MMP-2 were performed at the beginning and after 12 months in spironolactone and control group.

Results

There were no statistically significant differences in echocardiographic indices, PWV, BP (ABPM readings) and biochemical markers: MMP-2, serum aldosterone, TGF-β, IL-6, selectin-P, PTH level after 12 months of spironolactone treatment. There was statistically significant rise in osteopontin level after 12 months of spironolactone treatment. Episodes of life-threatening hyperkalemia were not reported.

Conclusions

Aldosterone antagonists use in PD patients seems to be safe. Longer duration or higher dosage of spironolactone seems to be more effective in improving cardiovascular system status in PD patients. Further studies are required to determine relationship between mineralocorticoid receptor blockade and mineral-bone disturbances in PD patients.

Forearm Resistance-Vessel Dilatation Function During Reactive Hyperemia in Patients With Resistant Hypertension

BACKGROUND

Forearm blood flow (FBF) measured during reactive hyperemia by venous-occlusion plethysmography assesses resistance-vessel dilatation function but has never been investigated in resistant hypertension. The aim was to evaluate the independent correlates of forearm resistance-vessel function parameters in resistant hypertensives.

METHODS

In a cross-sectional study, 274 resistant hypertensives performed 24-hour ambulatory blood pressure (BP) monitoring, 2D-echocardiography, aortic pulse wave velocity, and venous-occlusion plethysmography with baseline and hyperemic FBF and vascular resistance measurements. A subsample of 103 patients also performed ultrasonographic brachial artery endothelial function examination. Independent correlates of baseline and hyperemic vascular parameters were assessed by multiple linear regressions.

RESULTS

Median (interquartile range) baseline FBF was 3.1 (2.4-4.0) ml/min/100ml of tissue, and during hyperemia mean FBF rose to 7.0 (5.2-9.4) ml/min/100ml of tissue. Baseline FBF and resistance were independently associated with left ventricular mass index (partial correlations -0.14 and 0.13, respectively), whereas hyperemic parameters were independently associated with body mass index (BMI) (inversely for FBF, partial correlation: -0.18 to -0.21) and with the nocturnal BP fall (directly for FBF, partial correlation: 0.12-0.15), after adjustments for age, sex, mean arterial pressure, and baseline vascular parameters. In a separate analysis, a larger brachial artery diameter was associated with higher hyperemic FBF, but there were no associations between resistance-vessel and conduit-vessel dilatation function parameters.

CONCLUSION

In patients with resistant hypertension, left ventricular mass was the only correlate of baseline FBF and resistance, whereas higher BMI and lower nocturnal BP fall were independently associated with lower FBF and higher resistance during reactive hyperemia.

Effects of mineralocorticoid receptor antagonists on left ventricular mass in chronic kidney disease patients: a systematic review and meta-analysis

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) are used widely in treatment of heart failure, but their effects on cardiovascular complications and mortality of chronic kidney disease (CKD) are not well known. Thus, we aim to assess such therapeutic effects of MRAs on CKD.

METHODS

Electronic literature published in any language until Dec 31, 2015, was systematically searched on PubMed, Embase, and Cochrane Central Register of Controlled Trials. Primary outcome was left ventricular mass (LVM) or LVM index (LVMI), and secondary outcome was all-cause mortality and major adverse cardiovascular events (MACEs). Results of continuous outcomes were pooled using mean difference (MD) and standard mean difference (SMD). Risk ratios (RRs) with 95 % confidence intervals (CIs) were pooled using a random- or fixed-effects model.

RESULTS

Totally 12 studies (6 randomized controlled trials with 1003 participants) involving 4935 patients were included. MRA treatment versus non-MRA treatment resulted in a significant change of 0.93 SMD (standard mean difference) in LVM (LVMI), a significant reduction of 22 % in all-cause mortality, a significant reduction of incidence of MACEs (RR 0.65, P = 0.001), significantly higher prevalence rates of hyperkalemia (>5.5 mmol/L), but no significant change in prevalence rates of severe hyperkalemia (>6.0 mmol/L).

CONCLUSION

MRA benefits CKD patients in terms of LVMI, all-cause mortality, and MACEs with no incidence of severe hyperkalemia. Nevertheless, the real effects of MRAs on cardiovascular events and mortality as well as their safety in CKD patients should be identified by further studies with prospective and large-sample clinical trials.

Long-Term Effects of Low-Dose Spironolactone on Chronic Dialysis Patients: A Randomized Placebo-Controlled Study

The purpose of this 2-year multicentric, randomized, placebo-controlled study was to evaluate the long-term effects and adverse effects of spironolactone on chronic dialysis patients. A total of 253 non-heart failure dialysis patients with end-stage renal disease were randomly assigned to 2-year treatment with spironolactone (25 mg once daily, n=125) or a matching placebo (n=128) as add-on therapy. The primary outcome was a composite of death from cardiocerebrovascular (CCV) events, aborted cardiac arrest, and sudden cardiac death, and the secondary outcome was death from all causes. Other CCV-related indexes such as left ventricular mass index, left ventricular ejection fraction, heart rate variability, vascular endothelial function, and blood pressure-lowering effect were analyzed for patients who completed the whole 2-year follow-up study. Sociodemographic, clinical, and relevant laboratory data were also collected. During the 2-year follow-up, the primary outcome occurred less frequently in the spironolactone group vs the control group (7.2% vs 18.0%; adjusted hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.26-0.78). Death from CCV events occurred in 4.0% of patients in the spironolactone group and in 11.7% of patients in the control group. Neither aborted cardiac arrest nor sudden cardiac death was significantly reduced by spironolactone treatment. The secondary outcome occurred less frequently in the spironolactone group vs the control group (9.6% vs 19.5%; adjusted HR, 0.52; 95% CI, 0.29-0.94). Other CCV-related indexes except for heart rate variability were significantly improved. This study demonstrates that use of low-dose spironolactone in non-heart failure dialysis patients can effectively reduce the risks of both CCV morbidity and mortality with few side effects. Moreover, the beneficial effect was mediated through improving the endothelial function or reducing left ventricular size independent of blood pressure changes, rather than mediation through changes in salt or potassium handling in the kidney.

Aldosterone blockade in CKD: emphasis on pharmacology

Besides its epithelial effect on sodium retention and potassium excretion in the distal tubule, aldosterone promotes inflammation and fibrosis in the heart, kidneys, and blood vessels. As glomerular filtration rate falls, aldosterone is inappropriately elevated relative to extracellular fluid expansion. In addition, studies in CKD patients on angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and/or direct renin inhibitors have shown that aldosterone levels paradoxically rise in approximately 30% to 40% of patients on these renin-angiotensin system-blocking drugs. Hence, there is interest in using mineralocorticoid receptor blockers that directly target the inflammatory and fibrotic effects of aldosterone in CKD patients. This interest, however, is tempered by a number of unresolved issues, including the safety of using such drugs in advanced CKD and ESRD populations, and the potential for differences in drug efficacy according to race and ethnicity of patient populations. A better understanding of mineralocorticoid receptor blocker pharmacology should help inform future research directions and clinical practice decisions as to how best to use these agents in CKD.

Impact of aldosterone on osteoinductive signaling and vascular calcification

Vascular calcification is frequently found already in early stages of chronic kidney disease (CKD) patients and is associated with high cardiovascular risk. The process of vascular calcification is not considered a passive phenomenon but involves, at least in part, phenotypical transformation of vascular smooth muscle cells (VSMCs). Following exposure to excessive extracellular phosphate concentrations, VSMCs undergo a reprogramming into osteo-/chondroblast-like cells. Such 'vascular osteoinduction' is characterized by expression of osteogenic transcription factors and triggered by increased phosphate concentrations. A key role in this process is assigned to cellular phosphate transporters, most notably the type III sodium-dependent phosphate transporter Pit1. Pit1 expression is stimulated by mineralocorticoid receptor activation. Therefore, aldosterone participates in the phenotypical transformation of VSMCs. In preclinical models, aldosterone antagonism reduces vascular osteoinduction. Patients with CKD suffer from hyperphosphatemia predisposing to vascular osteogenic transformation, potentially further fostered by concomitant hyperaldosteronism. Clearly, additional research is required to define the role of aldosterone in the regulation of osteogenic signaling and the consecutive vascular calcification in CKD, but more generally also other diseases associated with excessive vascular calcification and even in individuals without overt disease.

Aldosterone blockade in chronic kidney disease

Although blockade of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers has become standard therapy for chronic kidney disease (CKD), renewed interest in the role of aldosterone in mediating the injuries and progressive insults of CKD has highlighted the potential role of treatments targeting the mineralocorticoid receptor (MR). Although salt restriction is an important component of mitigating the profibrotic effects of MR activation, a growing body of literature has shown that MR antagonists, spironolactone and eplerenone, can reduce proteinuria and blood pressure in patients at all stages of CKD. These agents carry a risk of hyperkalemia, but this risk likely can be predicted based on baseline renal function and mitigated using dietary modifications and adjustments of concomitant medications. Data on hard outcomes, such as progression to end-stage renal disease and overall mortality, still are lacking in patients with CKD.